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Analysis of the inhibition of food spoilage yeasts by vanillin
Abstract
The antimicrobial potential of vanillin, the major component of vanilla flavour, was examined against the growth of three yeasts associated with food spoilage, Saccharomyces cerevisiae, Zygosaccharomyces bailii and Zygosaccharomyces rouxii. Minimum inhibitory concentration (MIC) values of 21, 20 and 13 mM vanillin were determined for the three yeast strains, respectively. The observed inhibition was found to be biostatic. During fermentation, the bioconversion of sub-MIC levels of vanillin in the culture medium was demonstrated. The major bioconversion product was identified as vanillyl alcohol, however low levels of vanillic acid were also detected. Neither the vanillyl alcohol nor the vanillic acid was found to be antagonistic to yeast cell growth. The results indicate the importance of the aldehyde moiety in the vanillin structure regarding its antimicrobial activity and that the bioconversion of vanillin could be advantageous for the yeasts, but only at levels below MIC. These bioconversion activities, presumably catalysed by non-specific dehydrogenases, were shown to be expressed constitutively. It was observed that increased vanillin concentrations inhibited its own bioconversion suggesting that the activity required intact cells with metabolic capacity.
... Experiments have been performed with some spoilage yeasts as well. For instance, vanillin and grape phenolics such as pterostilbene, resveratrol, luteolin, p-coumaric acid and ferulic acid were investigated against the planktonic growth of S. cerevisiae, Z. bailii, Z. rouxii and other wine-related yeasts [28][29][30]. Phenolics from essential oils and foods, e.g., coumarins, curcumin and pyrogallol, as well as various plant polyphenolic extracts have been shown to be effective against yeast biofilms [9,19]. However, antimicrobial properties of many phenolic compounds, especially their effect on adhesion, are still unexplored in this group of microorganisms. ...
... Namely, they were identified in grape, apple and pitahaya residue samples after enzyme extraction and showed antimicrobial and antibiofilm activities against food-related bacteria [27,31]. The other compounds tested proved to be effective antimicrobial agents in other studies [28,32,33]. extract peptone dextrose (YPD) medium containing 4 g/L glucose (Biolab, Budapest, Hungary), 4 g/L peptone (Sigma-Aldrich, Munich, Germany) and 2 g/L yeast extract (Biolab, Budapest, Hungary). ...
... Namely, they were identified in grape, apple and pitahaya residue samples after enzyme extraction and showed antimicrobial and antibiofilm activities against food-related bacteria [27,31]. The other compounds tested proved to be effective antimicrobial agents in other studies [28,32,33]. ...
Phenolic compounds are natural substances that can be obtained from plants. Many of them are potent growth inhibitors of foodborne pathogenic microorganisms, however, phenolic activities against spoilage yeasts are rarely studied. In this study, planktonic and biofilm growth, and the adhesion capacity of Pichia anomala, Saccharomyces cerevisiae, Schizosaccharomyces pombe and Debaryomyces hansenii spoilage yeasts were investigated in the presence of hydroxybenzoic acid, hydroxycinnamic acid, stilbene, flavonoid and phenolic aldehyde compounds. The results showed significant anti-yeast properties for many phenolics. Among the tested molecules, cinnamic acid and vanillin exhibited the highest antimicrobial activity with minimum inhibitory concentration (MIC) values from 500 µg/mL to 2 mg/mL. Quercetin, (−)-epicatechin, resveratrol, 4-hydroxybenzaldehyde, p-coumaric acid and ferulic acid were also efficient growth inhibitors for certain yeasts with a MIC of 2 mg/mL. The D. hansenii, P. anomala and S. pombe biofilms were the most sensitive to the phenolics, while the S. cerevisiae biofilm was quite resistant against the activity of the compounds. Fluorescence microscopy revealed disrupted biofilm matrix on glass surfaces in the presence of certain phenolics. Highest antiadhesion activity was registered for cinnamic acid with inhibition effects between 48% and 91%. The active phenolics can be natural interventions against food-contaminating yeasts in future preservative developments.
... Therefore, high concentrations of vanillin in zein films are not necessary to exert antimicrobial action against S. cerevisiae. The optimal concentration of vanillin to be loaded corresponds to 10% w/w compared to zein, i.e., 6 mm, comparable to that observed in the work of Fitzgerald et al. (2003), in which inhibition of ≈50% of the yeast was achieved by working with a pure vanillin concentration of 5 mM. [48] In the work of Ngarmsak et al. (2006), it was shown that vanillin concentrations of <7 mm were able to completely inhibit yeast grown on fresh mango pieces. ...
... The optimal concentration of vanillin to be loaded corresponds to 10% w/w compared to zein, i.e., 6 mm, comparable to that observed in the work of Fitzgerald et al. (2003), in which inhibition of ≈50% of the yeast was achieved by working with a pure vanillin concentration of 5 mM. [48] In the work of Ngarmsak et al. (2006), it was shown that vanillin concentrations of <7 mm were able to completely inhibit yeast grown on fresh mango pieces. [49] Furthermore, Rupasinghe et al. (2006), observed that at vanillin concentra- tions of 6 mm, a 73% reduction can also be achieved against E. coli. ...
Electrospinning is a much‐explored technique in the membrane fabrication field, particularly in active food packaging. Despite the widespread use of this technique, there remains a significant gap in the literature regarding the actual economic evaluation of the viability of biomaterials compared to traditional plastics. This study seeks to fill this gap by developing electrospun, vanillin‐loaded zein membranes to evaluate their efficacy in terms of antimicrobial activity, biodegradability, and economic viability. From a sustainability perspective, the newly developed membranes show an impressive ability to inhibit yeast growth by 75%, with complete degradation observed in only 7 days. This underscores their potential to mitigate environmental impact and promote environmentally friendly packaging solutions to reduce both plastic waste and food loss while maintaining safety and quality. However, the economic sustainability of these membranes is still an open challenge. It becomes clear that the main bottleneck does not lie in the innovative production technology, but rather in the prices of raw materials, particularly natural additives. This underscores the need for supportive measures from institutions to incentivize the transition to sustainable packaging alternatives and the importance of the full circularity concept. This work shows that achieving the European goal of zero plastic waste requires concrete efforts.
... Introduction 4-Hydroxy-3-methoxybenzoic acid, commonly known as vanillic acid, is a widely used flavoring agent known for its creamy and sweet fragrance. 1 It is usually found in crystal or powder form, appearing either yellow or white. Vanillic acid is a bioactive compound and a natural antioxidant, exhibiting good pharmacological activity. ...
... 5 Recent studies have shown that bioconversion, catalytic, and enzymatic processes can produce vanillic acid from veratric acid, vanillin, ferulic acid, and coniferyl alcohol. 1,[6][7][8][9] Despite their potential, these studies face challenges such as low product concentrations, poor pH resistance impacting microbe health resulting in poor product quality, and slow fermentation rates. They also face difficulties in purifying the vanillic acids from wastewater streams and fermentation broth. ...
The aim of this study was to extract vanillic acid from an aqueous solution through reactive extraction. Vanillic acid is utilized in the food and beverage industry as a flavoring agent. Tri-n-butyl phosphate (TBP) served as the reactive extractant, while natural oils like sesame oil and groundnut oil acted as diluents. The recovery of vanillic acid from fermentation broth or wastewater poses challenges due to toxicity concerns. However, employing natural solvents in the extraction process can significantly reduce toxicity. Various parameters, such as extraction efficiency, loading ratio, distribution coefficient, and equilibrium complexation constant, were determined to evaluate the extent of extraction achieved. Groundnut oil emerged as more effective than sesame oil as a diluent, exhibiting a maximum distribution coefficient of 13.31 and an extraction efficiency of 93.01 % at 5.27 mmol L–1 of acid concentration and 40 % v/v of TBP. Additionally, the number of theoretical stages required for the reactive extraction system was calculated, resulting in five stages for groundnut oil and four stages for sesame oil.
... Its smell is renowned for being sweet and creamy, which is one reason it is generally used as a flavouring agent. 1 It occurs naturally in foods such as grapes, cereal grains, cherries, soy beans, guava and vanilla beans (Vanilla planifolia). 2 Other sources include herbs such as Machilus yaoshansis, Polygonum perfoliatum L., Iodes cirrhosa and Angelica sinensis. ...
... Numerous studies published recently contend that bioconversion, catalytic and enzymatic oxidation can produce VA from veratric acid, vanillin, ferulic acid and coniferyl alcohol. 1,[16][17][18][19] Although these studies appear to offer a viable approach for producing VA, they do have a multitude of shortcomings and challenges that must be solved if they are to compete on the global market. Their drawbacks include poor product concentration, acid pH resistance, slowed fermentation rates, and difficulties with purifying and separating VA from the wastewater streams or fermentation broth. ...
BACKGROUND
Vanillic acid, an aromatic carboxylic acid and a derivative of vanillin, is used as an additive in consumer goods for its aroma. Previously, most vanillic acid was produced through a petrochemical route, but as a consequence of stringent environmental policies, it is now produced by the biotransformation of ferulic acid. Vanillic acid is also found in the wastewater streams of paper‐pulp industries and olive‐oil mills. So, recovering vanillic acid from fermentation broth, either during bioproduction or from a wastewater stream, while minimizing toxicity, is a difficult task. In order to reduce the toxicity substantially, bio‐based solvents such as sunflower, mustard and rice bran oils were employed as diluents along with tri‐n‐butyl phosphate (TBP) as extractant in order to recover vanillic acid by reactive extraction.
RESULTS
The extraction performance was elucidated using terms such as distribution ratio, extraction efficiency, loading ratio and equilibrium complexation constant for different extractant–diluent combinations. The highest extraction efficiency and distribution ratio for the different solvents were in the following order: TBP + sunflower‐oil (72.02%–92.47%; 2.57–12.29) > TBP + rice bran‐oil (65.56%–90.55%; 1.90–9.58) > TBP + mustard‐oil(64.03%–89.87%; 1.78–8.87). The theoretical number of stages was determined as 4 to achieve a targeted extraction efficiency of 90%; these predictions were borne out experimentally.
CONCLUSION
In this study, vanillic acid was recovered from the aqueous phase using tri‐n‐butyl phosphate in sustainable, environmentally friendly, bio‐based solvents such as rice bran oil, sunflower oil and mustard oil. © 2024 Society of Chemical Industry (SCI).
... Recently, our group has reported the grafting of vanillin derivative polymer on PET surfaces for antibacterial activity [33]. Vanillin extracted from vanilla beans is well known to exhibit bacteriostatic activity against a wide range of bacteria [34,35]. Unfortunately, as mentioned previously, as many essential oils, vanillin exhibits high antibacterial performances against Gram-positive strains, but limited activity against Gram-negative strains. ...
... In contrast with the more potent phenolic antimicrobial compounds such as carvacrol or thymol that are bactericidal [66,67], literature describes a bacteriostatic inhibitory action of vanillin. Fitzgerald and al. [34] investigated extensively the effect of vanillin on the cytoplasmic membrane of bacteria and conclude that antimicrobial activity of vanillin results in the dissipation of ion gradients between the cell and the external environment and the inhibition of respiration. Moreover, they observed that antimicrobial activity of vanillin was found to be dependent of the nature of the cytoplasmic membrane. ...
This paper reports a strategy for the elaboration of highly performing antibacterial PET surfaces according to an eco-friendly photoinduced process. Modified PET surfaces were elaborated through the grafting of a three dimensional (3D) biopolymer derived from vanillin with antibacterial activity. Biobased polymer grafting was performed through a grafting-from photopolymerization approach initiated from a photoinitiator compound preliminary functionalized onto PET surface. Antibacterial activity of the elaborated materials was tested against Gram-positive (Rhodococcus wratislaviensis and Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) strains. Antibacterial activity of the biopolymer covalently linked onto PET surface was observed for all tested bacterial strains. Antibacterial effect of vanillin derivative coated onto PET material was combined with a multi-scale roughness induced through the grafting process giving antifouling behaviour to the material. Besides, to improve antibacterial activity of the modified material, biobased network was used as binding sites for photoembedding of antimicrobial silver nanoparticles. The hybrid material showed excellent antibacterial properties against Gram-positive and Gram-negative tested cells. The enhancement of material antibacterial activity against this wide range of pathogens resulted of a combination of different effects: the antibacterial activity of coated vanillin derivative and nanosilver combined with a surface nanostructuration imparting antifouling properties.
Grafting of biobased polymer network loaded with nanosilver onto PET material was characterized at various stages of the modification by UV–vis spectroscopy, water contact angle measurements, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The surface topography was studied by atomic force microscopy (AFM).
... 216 The toxicity of vanillin could be due to the aldehyde moiety and/or vanillin's hydrophobicity, which have been linked to its antimicrobial properties. 218 Aldehydes are good electrophiles and could form reaction products with biological compounds such as lipids, proteins and nucleic acids. 219 Vanillin has been studied for its role in controlling food spoilage, inhibiting the growth of yeasts with the minimum inhibitory concentration (MIC) as low as 13 mM. ...
... 219 Vanillin has been studied for its role in controlling food spoilage, inhibiting the growth of yeasts with the minimum inhibitory concentration (MIC) as low as 13 mM. 218 Meanwhile, the inhibitory concentration, IC50-24h of vanillin in E. coli is 3 mM. 219 It has been reported that aromatic aldehydes in general may be toxic to R. jostii RHA1 213 and the same could possibly be applied to our strain of Rhodococcus. ...
There has been much recent interest in using ionic liquids for processing
lignocellulosic biomass. While cellulose has an acknowledged application in
generating biofuels, it would be valuable to use the abundant lignin present as well.
Rhodococcus has been reported previously to degrade lignin. Therefore, it is
attractive to consider a scheme in which an ionic liquid is also used to enhance the
microbial breakdown of lignin (bioligninolysis). By using vanillic acid as model
compound (Chapter 3), results showed that Rhodococcus UKMP-5M is able to
degrade vanillic acid as a sole carbon source at 10mM concentration to give the
highest growth rate. An oxygen-dependent reaction degrades vanillic acid into
protocatechuic acid and formate in a previously undescribed metabolic pathway.
In Chapter 4, GC-MS demonstrated guaiacol as the major product of lignin
degradation and the lignin degradation assay indicates that the treatment of lignin
with ionic liquids assist the lignin degradation despite some ionic liquids showing a
toxicity effect on the cells. Toxicological studies (Chapter 5) demonstrated different
ionic liquids show varying toxicity to the bacteria. By using classical disk diffusion test
in screening 16 different ionic liquids, it was revealed that the toxicity is correlated
with the size of the ionic alkyl chain; however, the carbon atom count, not the
structure or the distribution of those atoms in the cation, correlates directly with the
toxicity. The strongest link was discovered with pH effects rather than with structure
in the toxicity of acidic ionic liquids. We also propose that the octanol-water partition
coefficient (Kow) has the controlling impact on the toxicity of ionic liquids. Bacterial
growth curves exhibited three different trends: a complete inhibition, an increase in
toxicity with an increase of ionic liquid concentration and the extension of the lag
phase due to bacterial adaptation.
This study established that Rhodococcus UKMP-5M could adapt and grow in
the presence of ionic liquids with 1-ethyl-3-methylimidazolium acetate, [Emim][OAc]
as the most promising candidate in designing an ionic liquid-facilitated system of
bioligninolysis.
... Although the mechanisms are still unclear, the authors showed that growth of the lactic acid bacterium OEnococcus oeni was enhanced in the presence of vanillin. Fungal species, on the other hand, can be inhibited by high concentrations of vanillin (Fitzgerald et al., 2003), and possibly for that reason, often possess the capability to convert vanillin into other phenolic derivatives like vanillyl alcohol (Fitzgerald et al., 2003). In this study, vanillin was found to be extracted from the wood, as shown by the relatively high vanillin concentrations in the negative controls, while vanillin concentrations in the jars with the synthetic microbial community were much lower, suggesting a microbial conversion of this compound. ...
... Although the mechanisms are still unclear, the authors showed that growth of the lactic acid bacterium OEnococcus oeni was enhanced in the presence of vanillin. Fungal species, on the other hand, can be inhibited by high concentrations of vanillin (Fitzgerald et al., 2003), and possibly for that reason, often possess the capability to convert vanillin into other phenolic derivatives like vanillyl alcohol (Fitzgerald et al., 2003). In this study, vanillin was found to be extracted from the wood, as shown by the relatively high vanillin concentrations in the negative controls, while vanillin concentrations in the jars with the synthetic microbial community were much lower, suggesting a microbial conversion of this compound. ...
Sour beers produced by barrel-aging of conventionally fermented beers are becoming increasingly popular. However, as the intricate interactions between the wood, the microbes and the beer are still unclear, wood maturation often leads to inconsistent end products with undesired sensory properties. Previous research on industrial barrel-aging of beer suggests that beer parameters like the ethanol content and bitterness play an important role in the microbial community composition and beer chemistry, but their exact impact still remains to be investigated. In this study, an experimentally tractable lab-scale system based on an in-vitro community of four key bacteria (Acetobacter malorum, Gluconobacter oxydans, Lactobacillus brevis and Pediococcus damnosus) and four key yeasts (Brettanomyces bruxellensis, Candida friedrichii, Pichia membranifaciens and Saccharomyces cerevisiae) that are consistently associated with barrel-aging of beer, was used to test the hypotheses that beer ethanol and bitterness impact microbial community composition and beer chemistry. Experiments were performed using different levels of ethanol (5.2 v/v%, 8 v/v% and 11 v/v%) and bitterness (13 ppm, 35 ppm and 170 ppm iso-α-acids), and beers were matured for 60 days. Samples were taken after 0, 10, 20, 30 and 60 days to monitor population densities and beer chemistry. Results revealed that all treatments and the maturation time significantly affected the microbial community composition and beer chemistry. More specifically, the ethanol treatments obstructed growth of L. brevis and G. oxydans and delayed fungal growth. The iso-α-acid treatments hindered growth of L. brevis and stimulated growth of P. membranifaciens, while the other strains remained unaffected. Beer chemistry was found to be affected by higher ethanol levels, which led to an increased extraction of wood-derived compounds. Furthermore, the distinct microbial communities also induced changes in the chemical composition of the beer samples, leading to concentration differences in beer- and wood-derived compounds like 4-ethyl guaiacol, 4-ethyl phenol, cis-oak lactone, vanillin, furfural and 5-methyl furfural. Altogether, our results indicate that wood-aging of beer is affected by biotic and abiotic parameters, influencing the quality of the final product. Additionally, this work provides a new, cost-effective approach to study the production of barrel-aged beers based on a simplified microbial community model.
... Besides its industrial and food application this compound has been the subject of several scientific investigations in the last years, such as the identification of antioxidant properties [10] , antimicrobial activity [11] [12] [13] , as well as antibiotic [14] [15] and anticancer actions [16] . Conversely, vanillin may also induce oxidative stress in yeast cells [17] . ...
The study describes the effect of vanillin derivative on the activity of aryl esterase in vitro. After that, the Estimated effectiveness of the enzyme aryl esterase, troponin T, and lipids. The research included the collection of 120 blood samples distributed to 60 blood samples of healthy people as a control group and 60 blood samples of patients with atherosclerosis who were diagnosed under the supervision of specialized doctors at Salah Eddin General Hospital / Catheterization Unit. Results showed that the vanillin derivative has an invigorating effect on the activity of aryl esterase, and that the degree of enzyme activation increases with the increase in the concentration of the derivative, while there was lower with a probability level (P≤ 0.0006) in the activity of aryl esterase from the serum of patients with atherosclerosis in addition, a significant increase at the probability level ( P ≤ 0.001) in the level of total cholesterol, triglycerides, LDL-C and VLDL-C, while there was decrease at the probability level (P ≤ 0.0004) in the level of HDL-C. Keywords: Aryl esterase, Vanillin derivative, Lipids, Atherosclerosis.
... Notably, in addition to their aromatic properties, these compounds have demonstrated antimicrobial activity (Fitzgerald et al., 2003). Vanillin, for instance, has been shown to inhibit the growth of bacteria and fungi such as Escherichia coli and Saccharomyces cerevisiae, and to exert cytotoxic effects on mammalian cells (Adeboye et al., 2014;Bezerra et al., 2016;Cheng et al., 2007). ...
Flavors and fragrances are essential for product quality, yet they are highly susceptible to contamination due to high moisture content and rich nutrients. This study investigates microbial growth, pH changes, volatile compound dynamics, and microbial community changes during the storage of flavors and fragrances. Results indicate that total viable counts (TVC) remained stable for the first three days but increased rapidly afterward, exceeding the acceptable limit of 5 log CFU/mL by day 7. The pH levels initially rose slightly, followed by a steady decline, which indicates spoilage progression. Gas chromatography–mass spectrometry (GC–MS) analysis revealed significant degradation of key aromatic compounds, such as 5-hydroxymethylfurfural (5-HMF), vanillin, and its derivative ethyl vanillin. Whole genome shotgun (WGS) sequencing demonstrated a marked increase in microbial community richness and diversity as storage progressed, with a notable shift in composition. Early storage stages were dominated by fungal species from the Ascomycota phylum, while later stages saw a rise in spoilage-associated bacteria, particularly from the Firmicutes and Proteobacteria phyla. Throughout the storage process, Zygosaccharomyces and its dominant species, Zygosaccharomyces bailii, remained prevalent, though their average relative abundance decreased from 81.26 to 32.29%. In addition, the bacterial species Oceanobacillus sojae and Niallia nealsonii showed significant increases in relative abundance, suggesting that bacteria were one of the key contributors to the spoilage of flavors and fragrances. Functional analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database indicated a shift in metabolic pathways within the microbial community, with heightened metabolic activity correlating with spoilage. These findings provide valuable insights for improving storage methods and quality control of flavors and fragrances.
... Vanillin is chemically explained as 4-hydroxy-3-methoxybenzaldehyde and a famous ingredient widely used in food products, cosmetics and drugs (Anklam et al. 1997). It has been defined as a flavoring compound, but it is also known for having antioxidant properties and for inhibiting yeasts and molds (Fitzgerald et al. 2003). Recent studies highlighted vanillin as a natural food preservative with antioxidants and antimicrobial properties. ...
Environmentally friendly technologies with regard to reducing the usage of commercial synthetic waxes are required for maintaining the quality of mandarin fruits during the post-harvest period. In this study, novel biocoatings that serve as a natural alternative to synthetic waxes were developed for obtaining sustained shelf life of freshly harvested mandarins. The effect of natamycin and vanillin as natural antimicrobial compounds on the post-harvest quality of mandarins were investigated by means of alginate-based edible coating. Alginate coating (1% w/v) formulations including 0.5% vanillin, 1.0% vanillin, 0.025% natamycin, 0.05% natamycin and without vanillin or natamycin were applied and compared with uncoated fruit as control. Weight loss, color change, fruit firmness, yeast and mold counts were examined over 21 days at 25 °C. Quality changes in mandarins such as losses of weight, color and softening changes were significantly delayed with alginate coatings. Brightness on the surfaces of fruits was improved by alginate coating layers. Fruit firmness decreased with storage time in control samples, while the firmness in coated samples remained relatively constant or increased. Moreover, yeast and mold counts considerably decreased (1.52 log cfu/g) for fruits coated with alginate coating incorporating 1% vanillin. Extension of the post-harvest storage of mandarin fruits could be performed by using alginate coating incorporating vanillin as an alternative to synthetic waxes.
... It is possible a small amount of vanillin was lost during manufacture or due to its slow release, as evidenced by the fact that nanofibers with added vanillin had a lesser inhibitory impact compared to pure vanillin powder. According to Fitzgerald et al. (2004), the MIC values for E. coli, L. monocytogenes, and L. plantarum were 15, 15, and 75 mg/mL, respectively [84]. While the conclusions of this study align with our results, there are differences in the MIC of vanillin, which can be attributed to variations in strains and testing techniques. ...
In this study, we successfully fabricated vanillin (VAN) incorporated poly (ethylene oxide) (PEO) and whey protein isolate (WPI) nanofibers and optimized the preparation conditions. The nanofibers were prepared at different percentages of PEO/WPI/VAN, and the characterization techniques of XRD, FTIR, FESEM, and DSC were employed to analyze the samples. Additionally, mechanical properties, and physicochemical were measured to identify the critical factors for nanofiber optimization. The best parameters observed at a PEO 10%: WPI 3% ratio of 80:20, producing narrower and smoother fibers (average diameter of 264.07 nm; additionally, the addition of VAN to the optimal PEO/WPI ratio (80:20) decreased fiber diameter. Furthermore, vanillin was incorporated into the optimized PEO/WPI nanofibers at concentrations of 1MIC (10 mg/mL) and 2MIC (20 mg/mL) to evaluate their antioxidant and antibacterial abilities before and after electrospinning. In summery, these findings suggest that the PEO/WPI nanofibers, with the addition of VAN, hold potential as a promising platform for future applications in the food and drug industries. Further research can build upon these findings to explore the specific functionalities and applications of these nanofibers in greater detail.
... The authors attributed the antifungal activity of the OPE to the aldehyde moiety in the vanillin. Additionally, vanillin was reported to pose a remarkable antimicrobial activity against (Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Zygosaccharomyces rouxii (Fitzgerald, 2003). ...
Olive pomace from an olive mill was collected in December 2021. Proximate analysis revealed that the major constituents of the pomace were fiber (60.85 %) and fat (11.91%). Extraction of the olive pomace by methanol provided a higher yield, phenolic content, and free radical scavenging ability than the ethanol extract, but the latter was used due to its lower toxicity level as the extract is used in foods. The extract contained high concentrations of phenolic compounds, particularly syringic, p-coumaric, vanillin, and caffeic acid which accounted for ~80% of the total phenolic content. When the olive pomace extract (OPE) was used (0.08%) in pasteurized white cheese (PWC), the counts of mesophilic aerobes were significantly reduced to 3.62 log10 CFU/g after 30d of storage at 5°C compared to the control (4.04 log10CFU/g) after the same storage period. The corresponding values for LAB were 3.38 log10 CFU/g and 3.79 log10 CFU/g, respectively. The yeasts and molds were eliminated from the cheese for 14d at all of the tested OPE concentrations (0.01% to 0.08%). Fortification of cheese with OPE alleviated the increase in titrable acidity in cheese during storage, but the fortified cheese exhibited sensory attributes similar to those of the control cheese. It can thus be concluded that fortification of PWC with OPE improves the chemical and microbial attributes of the cheese
... Vanillyl alcohol is considered as one of the most studied lignin-derived monomeric phenolic compounds, which is further oxidized to vanillin, an aroma molecule with wide application in industry. [7][8][9] In addition, reactive groups in vanillin can be functionalized easily, and thus, vanillin is also an interesting building block. 10,11 Various groups have developed synthetic catalytic protocols for the oxidation of vanillyl alcohol to vanillin. ...
In the modern era, sustainable development for the production of fine chemicals from abundant biomass by utilizing various chemical transformations has become a strong trend of research in the scientific community. This may provide a sustainable alternative to petrochemicals as the major source of fine chemicals. Lignin is an alternative major source of monomeric phenolic compounds, and the syntheses of fine chemicals by oxidising lignin-based monomeric phenolics are gaining serious attention. For instance, biomass derived vanillin or vanillyl alcohol can be oxidized to vanillic acid which has been employed as a new building block for the syntheses of various value-added products. In this context, an air-stable iron(ii) complex has been synthesized and utilized as an excellent base-metal catalyst for the selective oxidation of vanillyl alcohol to vanillic acid. We used hydrogen peroxide and tert-butyl hydroperoxide as green oxidants. These peroxidative oxidations of vanillyl alcohol to vanillic acid were performed in metal-free type-III deep eutectic solvents as green and sustainable reaction media. After the first set of oxidation reactions, the catalyst and the reaction medium were recycled five times without any noticeable change in catalytic performance. The CHEM21 green metrics toolkit was also used to examine the sustainable and green features of the optimized oxidation protocol for the conversion of vanillyl alcohol to vanillic acid. Low E-factors (4.65) suggest waste minimized sustainable oxidations of vanillyl alcohol to vanillic acid. Finally, vanillic acid was used as a starting material for the syntheses of several fine chemicals with various (potential) applications such as flavorants, odorants, surfactants and bio-based plasticizers.
... De la Croix was the first to note that the secondary metabolites, particularly the EO vapours, had antibacterial properties (Boyle, 1955). Since then, several biological activities, including insecticidal (Kim et al, 2003), antifungal (Fitzgerald et al, 2003) antibacterial (Oussalah et al, 2007) and antiviral (Schnitzler et al, 2007) activities, have been reported to be shown by EOs and their phytoconstituents. Most vegetable seeds, including perilla and sunflower seeds, include heterocyclic chemicals like pyrazine, which are essential to the flavour and quality of the products. ...
Fruits are an abundant source of minerals and nutrients. High nutritional value and easy-to-consume property have increased its demand. In a way to fulfil this need, farmers have increased production, thus making it available for consumers in various regions. This distribution of fruits to various regions deals with many associated problems like deterioration and spoilage. In a way, the common practices that are being used are stored at low temperatures, preservation with chemicals, and many more. Recently, edible coating has emerged as a promising preservation technique to combat the above-mentioned problems. Edible coating stands for coating fruits with bioactive compounds which maintains the nutritional characteristics of fruit and also enhances the shelf life. The property of edible coating to control moisture loss, solute movement, gas exchange, and oxidation makes it most suitable to use. Preservation is uplifted by maintaining the nutritional and physicochemical properties of fruits with the effectiveness of essential oils. The essential oil contains antioxidant, antimicrobial, flavor, and probiotic properties. The utilization of essential oil in the edible coating has increased the property of coating. This review includes the process of extraction, potential benefits and applications of essential oils in food industry.
... Vanillin comprises different functional groups, such as aldehyde, hydroxyl, and ether attached to an aromatic ring. The aldehyde group of the vanillin structure is thought to play an important role in the inhibitory activity against fungi by causing cell membrane disruption [20]. Furthermore, inhibition of DNA, RNA, and protein synthesis [21], glucose uptake [22], and enzyme activities [23,24] have also been mentioned. ...
An oral obturator is a prosthesis used for a variety of dental conditions to help patients regain their abilities after trauma, surgeries, or having congenital defects. It is commonly made from polymethyl methacrylate (PMMA) resin. Despite that, this resin appliance can give rise to a condition for microbial adhesion and colonization on the resin surface itself and the mucosa beneath. This can place patients at a greater risk of infection. Oral infections caused by Candida species are found to be more common, particularly in immunologically compromised patients and those with other conditions in the oral cavity that often include oral prosthetic appliances. Obturator resin incorporated with vanillin has been produced and shown to have antimicrobial properties against some bacteria and yeasts. The purpose of this study was to determine the adhesion of candida to vanillin incorporated obturator resin. The auto-polymerized resin samples (Orthocryl® EQ, Dentaurum, Germany) were prepared with different concentrations of vanillin incorporation (0.1%, 0.5%, and 1% vanillin w/w). All samples were coated with sterile saliva and incubated at 37 °C for 60 min. The adhesion assay was done with four species of candida (C. albicans ATCC 10231, C. krusei ATCC 14243, C. glabrata ATCC 15126, and C. tropicalis ATCC 1369). The resin samples were placed in a 24-well plate containing 10⁷ CFU/mL of candidal suspension and incubated in a shaking incubator (120 r/min) at 37°C for 2 h for candidal adhesion. Non-adherent cells were removed by washing with phosphate buffer saline (PBS) solution. The remaining adherent cells on the obturator resin surface were quantified by the WST Microbial Cell Counting Kit (Dojindo Molecular Technologies, USA). The Kruskal-Wallis test, followed by Dunn’s method, was applied for statistical analysis. The results showed that the addition of 0.5% and 1% w/w vanillin to oral obturator PMMA resin could significantly reduce the adhesion of all Candida species except that of C. krusei, for which a reduction effect was observed at 1 % vanillin. The percentage reduction of candidal adhesion on obturator resin varies from 9% to 35%, which was highest on C. albicans, followed by C. glabrata (24%), and C. tropicalis (21%). No reduction effect was observed at 0.1% vanillin on all Candida species. In conclusion, vanillin-incorporated oral obturator resin displayed a reducing effect on the adhesion of all tested Candida species. C. albicans was the most susceptible species, while C. krusei was the most resistant. The mechanisms of action could possibly be the aldehyde group of the vanillin structure that causes cell membrane damage, interferes with DNA, RNA, and protein synthesis, as well as enzyme activities within the yeast cell. This newly developed PMMA resin could be valuable for the prevention or as an adjunctive treatment for controlling oral candidal infection among patients who use oral obturators.
... The essential leaf oils have a strong flavor and volatile molecules with intense antioxidant activity (Mimica et al., 2003), antifungal (Fitzgerald, Stratford, & Narbad, 2003), and antibacterial ( (Olofsson, Hultqvist, Hellgren, & Holmdahl, 2014). Hexadecanoic acid is well-known for its antiinflammatory properties (Aparna et al., 2012) and cytotoxic potential (Yeo et al., 2016). ...
In Asia, mulberry has long been used to treat various infectious and internal ailments as a traditional medication. The compounds found in it have the potential to improve human health. Because there is no approved and defined evaluation procedure, it has not been formally or scientifically recognized. As a result of these investigations, a new frontier in traditional Chinese medicine has opened up, with the possibility of modernization, for the interaction between active components of mulberry and their biological activities. These studies have used current biotechnological technologies. For ages, mulberry has been used as an herbal remedy in Asia to cure various diseases and internal disorders. It has a high concentration of bioactive chemicals that benefit human health. The most abundant phenolic components extracted from white mulberry leaves are flavonoids (Kuwanons, Moracinflavans, Moragrols, and Morkotins), phenolic acids, alkaloids, and so forth. Flavonoids, benzofurans, chalcones, and alkaloids have been discovered to have cytotoxic effects on human cancer cell lines. There is growing evidence that mulberry fruits can potentially prevent cancer and other aging‐related disorders due to their high concentration of bioactive polyphenolic‐rich compounds and macro and micronutrients. Anthocyanins are rapidly absorbed after eating, arriving in the plasmalemma within 15–50 min and entirely removed after 6–8 hr. Due to a lack of an approved and consistent technique for its examination, it has yet to be formally or scientifically recognized. The mulberry plant is commercially grown for silkworm rearing, and less attention is paid to its bioactive molecules, which have a lot of applications in human health. This review paper discusses the phenolic compounds of white mulberry and black mulberry in detail concerning their role in cancer prevention.
... [11] Vanillin's anti-microbial properties against yeasts and other microorganisms have been evaluated. [12,13] However, no research has been performed to check the efficacy of this plant on the oral micro-environment, making the use of Vanilla planifolia in dentistry unexplored. Literature search revealed no studies that evaluated the effect of this plant on dental caries or dental pain. ...
Introduction:
Over the past century, several antibiotics have been discovered and used to treat various microbial diseases. However, over the past few decades, with the emergence of anti-microbial resistant strains of microbiomes, it has become increasingly necessary to discover and develop alternative anti-microbial agents. Herbal formulations have shown promising results in the past decade. However, many herbal formulations remain unexplored. The present study aims to explore the anti-microbial properties of a newly prepared Vanilla planifolia extract.
Methodology:
Vanilla planifolia leaves were collected, shade-dried, and then powdered. The powdered leaves of Vanilla planifolia (100 gm) were extracted by the cold percolation method with 300 ml ethanol at room temperature for 72 hours. The extracts were then tested for its constituent anti-microbial activity by the agar well method and disk diffusion method against different commonly found oral micro-biomes. The zones of inhibition were noted and measured, and the results were derived. Statistical analysis was performed using the Student t-test (P <_ 0.001). Based on the statistical analysis, conclusions were drawn.
Results:
The ethanolic extracts of Vanilla planifolia on the agar plates showed considerable anti-microbial activity in both the test methods against Staphylococcus aureus, Streptococcus mutans, and Enterococcus. However, no effect was found against Candida albicans. There was no significant difference in the results obtained by the two test methods (P >_ 0.001).
Conclusions:
This experimental study presents a medicinal plant, an orchid Vanilla planifolia, which demonstrates the presence of essential anti-microbial agents in it, making it a potent, potential dental biomaterial with a positive and benefitting effect on the oral micro-environment.
... Vanillin is a phenolic compound that has been widely used as a food ingredient and flavoring agent worldwide. It is also used as a flavor enhancer in various food items 11 , as a food preservative 8 , pharmaceuticals, medical, agriculture, cosmetics and various industries 20 . It has been obtained traditionally from cured seed pods of Vanilla planifolia, Vanilla tahitensis, Vanilla pompona (natural vanillin) and petrochemicals. ...
Natural aromatic compounds are in growing demand in the food and pharmaceutical market. Due to limited sources for natural aroma compounds, there is an increasing interest in developing different sources for vanillin and another aromatic aldehydes. Some microbial species have been reported to produce aromatic aldehyde as an intermediate product in the degradation pathway of phenylpropanoids. The present work was carried out to isolate microbial species, capable of transforming isoeugenol to vanillin and its metabolites. Bacillus firmus strain JAA1 isolated from soil sample was found to transform isoeugenol into vanillin. The ability to produce vanillin from isoeugenol as substrate was screened through resting cells. The bacterial strain possessed the tolerance to grow in presence of isoeugenol as the sole carbon source. The bioconversion of isoeugenol to vanillin by the strain Bacillus firmus JAA1 was detected in the growing culture and its metabolite was detected through gas chromatography mass spectroscopy.
... Contemporary research has proposed a number of pharmaceutical benefits of vanilla (for example, in fighting cancer [69][70][71] ). Furthermore, like many herbs and spices, vanillin has been shown to help preserve food by inhibiting the activity of food spoilage yeasts, thus functioning as a highly effective antimicrobial agent 72,73 (note that vanilla is considered a spice 74 ). In the thirteenth century, Aztecs mixed cured vanilla pods with copal to scent their temples during sacred rituals, while the green bean was used medicinally (for example, to treat venomous insect bites and heal wounds 27 ). ...
Our food choices and consumption behaviours are often influenced by odour hedonics, especially in the case of those orthonasally experienced aromas (that is, those odours that are food-related). The origins of odour hedonics remain one of the most intriguing puzzles in olfactory science and, over the years, several fundamentally different accounts have been put forwards to try and explain the varying hedonic responses that people have to a wide range of odorants. Associative learning, innate and molecular accounts of odour pleasantness have all been suggested. Here the origins of the hedonic response to vanilla, which is one of the most liked smells cross-culturally, are explored. The history of vanilla’s use in food and medicine is outlined, with a focus on its neurocognitive appeal. While vanilla is one of the most widely liked aromas, it is also rated as smelling sweet to most people. Food scientists are becoming increasingly interested in the possibility that such ‘sweet smells’ could be used to help maintain the sweetness of commercial food products while, at the same time, reducing the use of calorific sweeteners. Such an approach is likely to be facilitated by the low cost of artificial vanilla flavouring (when compared with the high and fluctuating price of natural vanilla pods). Hedonic responses to food odour may be rooted in evolution, associated learning or the physiochemical structure of odorants. Here, vanilla is used to study these mechanisms in an effort to understand why some flavours are universally liked and how that might be advanced in food science.
... In addition, it can be used as a precursor in synthesizing other flavorings, as previously stated. In the flavoring industry, synthetic vanillin is a solution of pure vanillin, usually derived from synthetic sources [79][80][81][82]. Due to the extreme shortage and high price of bioderived vanillin extract, the synthetic production methodology has largely taken over as the preferred production method. ...
Bio-based feedstock utilization for the green manufacturing of valuable organic compounds is reckoned as a crucial goal to be achieved by the global scientific communities in this century to encourage sustainable business while saving the fixed stock of fossil fuels. Vanillin is a key aromatic flavoring compound extensively used in the food and cosmetic industries. Around 12,000 tons of vanillin are widely consumed in a year, and less than 1% of it is obtained from vanilla beans through the costly extraction process. Extensive scrutiny of the existing literature shows that vanillin can be produced bio-technologically from several sources. Currently, the production of vanillin from lignin is enticing because it caters to the supply of renewable aromatics in nature. However, the scaled-up applications of the biological routes are limited owing to the slow process, the requirement for precise process control, the risk of product inhibition and degradation, bacterial strain selection, and a complex downstream purification. These challenges highlight the need for vanillin synthesis through an alternate eco-friendly combined biological–chemical route. This review gives an insight into the development of a novel membrane-integrated photo-microreactor system for converting lignocellulosic biomass to vanillin and downstream purification, which appears to be the most promising bio-chemical, environmentally friendly, and cost-effective choice. The status quo of lignin extraction, purification, recovery, and techno-economic assessment for scale-up are also discussed thoroughly, enabling researchers to comprehend the possible lignocellulosic agro-biomass material conversion methodologies for the production of valuable aromatic compounds.
... Bloem et al. [25] showed that Oenococcus oeni was not able to convert vanillic acid into vanillin. Micro-organisms, such as yeast, are also able to metabolize vanillin to vanillic acid or vanillyl alcohol by oxidoreductase enzymes [26]. Phelps and Young [27] demonstrated that the plant phenolic compounds ferulic and syringic acid were readily degraded by consortia of bacteria from this site under methanogenic, sulfidogenic, and denitrifying conditions. ...
The literature reports that the consumption of common buckwheat (Fagopyrum esculentum Moench), exactly the polyphenols it contains, is associated with a wide spectrum of health benefits. Therefore, the determination of the bioaccessibility of phenolic acids and flavonoids from buckwheat biscuits formulated from liquid-state fermented flours (BBF) by selected lactic acid bacteria (LAB) after gastrointestinal digestion was addressed in this study. Bioaccessibility could be defined as the fraction of a compound that is released from the food matrix in the gastrointestinal lumen and used for intestinal absorption. The bioaccessibility of eight phenolic acids (protocatechuic, vanillic, syringic ferulic, caffeic, sinapic, p-coumaric, and t-cinnamic) and six flavonoids (epicatechin, vitexin, orientin, apigenin, kaempferol, and luteolin) were provided for BBF and BBC (buckwheat biscuits prepared from fermented and unfermented flours, respectively). The bioaccessibility indexes (BI) indicated the high bioaccessibility of phenolic acids and improved bioaccessibility of flavonoids from BBF. Moreover, the data provide evidence for the suitability of selected LAB strains to be used as natural sour agents for further bakery product development rich in phenolic acids and flavonoids with LAB-dependent bioaccessibility.
... Dorman and Deans (2000) investigated the bactericidal potentials of eugenol against twenty five pathogenic bacteria and it was observed that only one strain was resistant (Dorman and Deans, 2000). Phenylpropene, vanillin, inhibits bacteria and yeasts also a range of mycelial inhibition was observed in toxigenic molds (Fitzgerald et al., 2003(Fitzgerald et al., , 2004(Fitzgerald et al., , 2005Rupasinghe et al., 2006;Hyldgaard et al., 2012). ...
The unending needs and demands for chemical free preservatives in food industry are on the increase due to the facts that diseases like cancer and complications from oxidative stress have been linked to the xenobiotics we eat in foods as preservatives. There is need for safe means of preserving our foods without side effects and that is why the world needs bio-preservative in all forms to augment both the nutritional properties and shelf life of food products. Bio-preservatives like bacteriocins produced from organisms with GRAS status, essential oils, vinegar, herbs/spices and sugar/salt reviewed in this work have shown credible antimicrobial properties against spoilage/food borne pathogenic and toxigenic microorganisms thus served as good bio-preservative agents suitable for a dispensation yearning for green solution areas of food improvement and preservation. This review provides an overview of the importance of bio-preservatives in food safety and nutritional augmentation needed in food industry as a whole.
... The vanilla pods are widely used in foods and beverages (approximately 60%), perfumes and cosmetics (approximately 33%), and pharmaceuticals (approximately 7%) (Priefert et al. 2001) without potential risks to human health. Vanillin has showed antimicrobial activity against molds and yeasts such as Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Aspergillus sojae, wood decay fungi, and bacteria such as Mycobacterium smegmatis, Aspergillus oryzae (Fitzgerald et al. 2003;Friedman et al. 2003;Ihssen et al. 2014). The antifungal activity of vanillin against wood decay fungi indicates its potential usage for wood protection. ...
The improvement of wood decay resistance is more inclined to eco-friendly methods such as the application of natural products, but the low durability of some natural products as wood preservatives limits their applications. In this study, vanillin catalyzed by laccase was grafted into poplar wood to increase wood decay resistance and can remain in wood for longer period. The reaction system of vanillin, ABTS, laccase and phosphate buffer solution was impregnated into poplar wood using vacuum-pressure method, and reacted at 40 °C for 6 h. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR) were used to confirm the grafting reaction actually occurring during the process. The decay resistance, leaching resistance and mechanical strength of grafted wood were evaluated. Energy-dispersive X-ray (EDX) mapping was used to characterize the vanillin distribution. The results indicated that vanillin grafted poplar wood had good decay resistance, leaching resistance and higher strength. The mass loss of grafted poplar wood exposed to white-rot fungi [Trametes versicolor (L. ex Fr.) Quél.] and brown-rot fungi [Gloeophyllum trabeum (Pers.: Fr.) Murr.] decreased from original 46 and 13% to 9 and 4%, respectively, even after leaching. The modulus of rupture (MOR) and modulus of elasticity (MOE) of the grafted poplar were 11 and 26% stronger than original poplar wood. Vanillin was found in wood cell wall. It was actually esterified onto wood catalyzed by the laccase.
... The anti-bacterial activity of D. hamiltonii was also evaluated by Devi and Latha [48], who obtained an inhibitory effect against different bacterial strain, viz., E. coli, K. pneumoniae, S. typhi, P. mirabilis, V. cholerae, S. sonnie, Serritias species, S. aureus, and B. subtilis by the disc diffusion method. Fitzgerald et al. [49] identified the activity of 2H4MB against both Gram-positive and Gram-negative bacteria. Saradha and Bharti [50] evaluated the anti-bacterial efficiency of various solvents leaf and tuberous root of D. nervosa by using the agar well diffusion method against the five bacterial strains. ...
The steno-endemic species from the genus Decalepis are facing a high level of threat due to destructive wild harvesting. The genus claimed its paramount importance to mankind due to its unique tuberous root characteristics and exhibits a wide range of biological and medicinal properties, and is used in pharmaceutical and food industries. Plants of this genus are endemic to limited areas of peninsular India, such as the Eastern and Western Ghats, and according to the International Union for Conservation of Nature (IUCN), species from the genus Decalepis are considered globally critically endangered. The genus comprises of five species namely Decalepis hamiltonii Wight & Arn., Decalepis arayalpathra (J. Joseph & V. Chandras.) Venter, Decalepis salicifolia (Bedd. ex Hook. f.) Venter, Decalepis nervosa (Wight & Arn.) Venter, and D. khasiana (Kurz) Ionta ex Kambale. All the species of the genus Decalepis are being used by the tribal people and also in traditional Indian and Chinese medicine. International trade for this plant is also increasing, resulting in overharvesting. The traditional method of propagation, viz., seed germination and vegetative, are limited and jeopardizes the species population, whereas plant tissue culture provides the opportunity for extensive production of the plant in vitro without sacrificing their natural habitats. This review is aimed to systematize the up-to-date facts related to the Genus Decalepis with the exploration of their geographic distribution, chemical profile, pharmacology, biological activities, micropropagation, somatic embryogenesis, synthetic seed, and genetic transformation.
... Vanillic acid is a phenolic compound and one of the main micropollutants commonly present in agro-industrial wastewaters [4][5][6][7]. Nevertheless, it is also known because of its valuable use as a fragrance [8]; as an additive, flavoring, and coloring agent [8,9]; and a medical product [10,11]. In the literature, there are several techniques for vanillic acid recovery such as distillation, extractive separation, crystallization, electrodialysis, and ion exchange [12]. ...
The management of agricultural waste is an important issue related to environment protection, as the inappropriate disposal of this waste yields negative effects on the environment. Proper management of industrial effluents is totally aligned with sustainable development goal (SDG) number six “clean water and sanitation”, as well as partially related to other several SDG. In this work, two agricultural waste materials were used for vanillic acid recovery from wastewater. In this scenario, vanillic acid could be considered as both an organic pollutant present in several industrial effluents and a high added-value product when isolated. Therefore, its removal from wastewaters, as well as its recovery and isolation, are very interesting from environmental and economical points of view. Peanut and pistachio shells were studied as no-cost and readily accessible potential adsorbents for the removal and recovery of vanillic acid from aqueous solutions. The evolution of equilibrium isotherms of vanillic acid on both biosorbents was investigated. Three isotherm models (Langmuir, Freundlich, and Temkin) were tested to fit the experimental equilibrium data and compared. The Langmuir model provided the best correlation for vanillic acid biosorption onto both peanut and pistachio shells. Finally, the negative values of ΔG indicated that the biosorption process was spontaneous and thermodynamically favorable for both agricultural waste materials. Accordingly, peanut and pistachio shells were shown to be very efficient low-cost adsorbents, and a promising alternative for vanillic acid recovery from industrial wastewaters.
... EOs are widely used in various countries as food preservatives and medicine, cosmetics and perfumes. EOs and their phytoconstituents have been reported to exert a broad spectrum of biological activities (such as antifungal, insecticidal, antibacterial, and antiviral) (Fitzgerald, 2003;Schnitzler et al., 2007). Research delving into the application of EOs as antimicrobial agents has increased due to their wide spectrum of activities and the property of being GRAS (generally recognized as safe) with natural origins (Nedorostova et al., 2009). ...
Bacteriocins are ribosomally synthesized peptides to inhibit food spoilage bacteria, which are widely used as a kind of food biopreservation. The role of bacteriocins in therapeutics and food industries has received increasing attention across a number of disciplines in recent years. Despite their advantages as alternative therapeutics over existing strategies, the application of bacteriocins suffers from shortcomings such as the high isolation and purification cost, narrow spectrum of activity, low stability and solubility and easy enzymatic degradation. Previous studies have studied the synergistic or additive effects of bacteriocins when used in combination with other hurdles including physics, chemicals, and microbes. These combined treatments reduce the adverse effects of chemical additives, extending the shelf life of food products while guaranteeing food quality. This review highlights the advantages and disadvantages of bacteriocins in food preservation. It then reviews the combined effect and mechanism of different hurdles and bacteriocins in enhancing food preservation in detail. The combination of bacterioncins and other hurdles provide potential approaches for maintaining food quality and food safety.
... If 1 : 1 mixture of acetonitrile/water (entry 20) and methanol/water (entry 21: 75%) were used, 61 (entry 20) and 75% (entry 21) conversions to vanillin were obtained, respectively. In all the previous cases (entries [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], the organic solvents (ethanol, acetone, THF, acetonitrile, and methanol) are highly miscible with water and generally good conversions were noted. The following oxidations (entries 22-25) of vanillyl alcohol were performed in mixtures (1 : 1) of organic solvents (ethyl acetate, DCM, toluene, hexane), which are not miscible with water. ...
The need of sustainable development in the modern era has driven the transformation of biomass for the production of fine chemicals into a strong trend of research. The aerobic oxidation of lignin-derived monomeric phenolics for the synthesis of various value-added products has attracted significant attention of the scientific community. In particular, enormous research interest has been devoted to the aerobic oxidation of vanillyl alcohol to vanillin, which is an important aroma chemical with wide applications. Four copper(ii) complexes were synthesized for this purpose. The coordination of the Schiff base ligand L1 containing pendant thioether arm with copper(ii) perchlorate and copper(ii) chloride yielded homoleptic complex 1a and dinuclear complex 2a, respectively. Similar coordination of the NNS amine ligand L2 with copper(ii) perchlorate and copper(ii) chloride resulted in the formation of homoleptic complex 1b and mononuclear complex 2b, respectively. All four air stable complexes were tested for the aerobic oxidation of vanillyl alcohol to vanillin at ambient conditions in the presence of a catalytic amount of the TEMPO radical. Mononuclear complex 2b displayed the best catalytic activity. Species 2b is highly selective for the conversion of vanillyl alcohol to vanillin in various green solvent mixtures. Catalyst 2b is highly recyclable and did not show any reduction of catalytic activity after three cycles. Finally, the green and sustainable credentials of various catalytic protocols under various reaction conditions were compared with the help of CHEM21 green metrics toolkit. A plausible catalytic pathway is proposed based on the published reports and experimental evidences.
... It is also evident that their ability to preferentially partition from water to membrane structures and penetrate the membrane are important factors that have a bearing on the sensitivity or resistance of exposed cells [45][46][47] . Fitzgerald et al. 50 found that the antimicrobial functionality was due to aldehyde groups in essential oils components and inactivation of decarboxylase enzymes in the cell. The nonphenolic components are also potent antimicrobials and have activity against a wide range of microorganisms. ...
This study focuses on the variation of the contents, chemical profiling and biological activities among fresh and dried leaves essential oils of Olea europaea L. Chemlali cultivar. The essential oils (EO) of the fresh and shade dried leaves of O. europaea were obtained by hydro-distillation and analyzed by gas chromatography-mass spectrometry. Antimicrobial activities were assessed by the evaluation of MICs and MCCs standards. Both oils showed significant quantitative and qualitative differences in their chemical composition. Indeed, 25 and 47 components were identified in the fresh and shade dried leaves essential oils, respectively. The fresh leaves essential oils were dominated by α-farnesene (17.85 %) and β-maaliene (17.16 %) while n-hexadecanoic acid (7.44% ) was the major component of shade dried leaves essential oils. Moderate antioxidant activity was shown for both essential oils. The essential oils of dried leaves exhibited higher antimicrobial activity with MICs values ranging between 1 and 2 mL L⁻¹ and MFCs ranging between 1 and 4 mL L⁻¹, whereas the MBCs of oils of fresh leaves ranged between 3.25 and 26 mL L⁻¹, and MFCs ranged between 3.25 and 6.5 mL L⁻¹. The detected reduction in the viability of standard bacteria, higher than 5 log units within a contact time of 5 min, was obtained by 0.75 % (v/v) dried and 1.25 % (v/v) fresh leaves essential oils. Concentrations of 3 % (v/v) dried and 6 % (v/v) fresh leaves essential oils resulted in a reduction in viability higher than 4 log units for the standard fungi, within a contact time of 5 min.
... It is widely known for its creamy fragrance. As a result, it is generally used as a flavouring or scent additive [1]. It has the appearance of white/ yellow powder or crystals. ...
Lactic acid is a carboxylic acid that is important due to its applications in various industries like pharmaceutical, cosmetics, chemicals, and food industries. It can be used for the production of ethanol, acrylic polymers, and propylene glycol. However, lactic acid extraction from downstream is a major challenge, hence an attempt was made to recover the acid by liquid-liquid extraction from the aqueous stream. In this paper, the extraction of lactic acid from the water stream was done using rice bran, sesame, and mustard oil. The experimental data were defined in different parameters viz. distribution coefficient (KD) and extraction efficiency (η) at 298.15 1 K. The distribution coefficient and extraction efficiency were found as follows: Sesame oil (0.28, 22.37%) > Rice Bran oil (0.19, 16.66%) > Mustard oil (0.13, 12.16%).
... Remarkably, the six model phenolic compounds (ferulic acid, vanillin, vanillic acid, ρ-hydroxybenzoic acid, syringaldehyde, and ρ-coumaric acid) and polyphenolic compounds tannin were not detected; however, the concentration of the total soluble phenolic compounds was approximately 2150.37 mg L −1 (the concentrations of monophenolic and polyphenolic compounds were 1024.65 and 1125.72 mg L −1 , respectively.) in the RHSAH group (Table 2). It has been reported that the biodegradation or bioconversion of phenolic compounds is mainly involved in redox reactions catalyzed by reductase dependent on cofactor NADH, 26 and dicarboxylic reaction catalyzed by phenolic acid decarboxylase, 27,28 which can convert phenolic compound to relatively low toxic compounds to microorganisms and increase the phenolic compound tolerance. However, we determined that the total phenolic compound concentration was significantly consistent during the process of fermentation by strain M523 and M183 in RHSAHFM (Supporting Information, Table S1), which illustrated that the mutant strain M523 has a high phenolic compound tolerance. ...
BACKGROUND
Monascus pigments (MPs) produced by the genus Monascus, have been utilized for more than 2000 years in the food industry. In the present study, by submerged batch‐fermentation (SBF), we were able to obtain a mutant strain with a high tolerance of inhibitory compounds generated from rice husk hydrolysate, allowing the production of MPs.
RESULTS
The mutant strain, M. Purpureus M523 with high rice husk hydrolysate tolerance was obtained using the atmospheric and room temperature plasma (ARTP) screening system, producing 39.48 U mL⁻¹ extracellular total MPs (yellow and orange MPs), using non‐detoxified rice husk diluted sulfuric acid hydrolysate (RHSAH) as the carbon source in SBF. Extracellular MPs (exMPs) production was enhanced to 72.1 and 80.7 U mL⁻¹ in supplemented SBF (SSBF) and immobilized fermentation (IF) using non‐detoxified RHSAH, with productivities of 0.16 and 0.37 U mL⁻¹ h⁻¹, respectively. In addition, our findings revealed that despite having a high RHSAH tolerance, the mutant strain was unable to degrade phenolic compounds. Furthermore, we discovered that inhibitory compounds, including furfural (Fur) and 5′‐hydroxymethyl furfural (5′‐HMF), not only inhibit MP biosynthesis, but also regulate the conversion of pigment components.
CONCLUSION
The low‐cost agricultural by‐product, rice husk, can serve as an efficient substitute for MP production with high productivity via IF by Monascus spp. © 2021 Society of Chemical Industry.
... The metabolism of vanillin and its derivatives by microorganisms, especially bacteria, has been well studied [11]. Vanillin is toxic in low concentrations for many microorganisms and therefore the ability to degrade vanillin is essential for microorganisms that live in natural habitats or are used in industrial processes where vanillin is present in significant amounts [12,13]. Several vanillin metabolic pathways have been described in microorganisms [11]. ...
Background
The aromatic compounds vanillin and vanillic acid are important fragrances used in the food, beverage, cosmetic and pharmaceutical industries. Currently, most aromatic compounds used in products are chemically synthesized, while only a small percentage is extracted from natural sources. The metabolism of vanillin and vanillic acid has been studied for decades in microorganisms and many studies have been conducted that showed that both can be produced from ferulic acid using bacteria. In contrast, the degradation of vanillin and vanillic acid by fungi is poorly studied and no genes involved in this metabolic pathway have been identified. In this study, we aimed to clarify this metabolic pathway in Aspergillus niger and identify the genes involved.
Results
Using whole-genome transcriptome data, four genes involved in vanillin and vanillic acid metabolism were identified. These include vanillin dehydrogenase (vdhA), vanillic acid hydroxylase (vhyA), and two genes encoding novel enzymes, which function as methoxyhydroquinone 1,2-dioxygenase (mhdA) and 4-oxo-monomethyl adipate esterase (omeA). Deletion of these genes in A. niger confirmed their role in aromatic metabolism and the enzymatic activities of these enzymes were verified. In addition, we demonstrated that mhdA and vhyA deletion mutants can be used as fungal cell factories for the accumulation of vanillic acid and methoxyhydroquinone from guaiacyl lignin units and related aromatic compounds.
Conclusions
This study provides new insights into the fungal aromatic metabolic pathways involved in the degradation of guaiacyl units and related aromatic compounds. The identification of the involved genes unlocks new potential for engineering aromatic compound-producing fungal cell factories.
... Its content can be quantified by conventional methods such as ultraviolet-visible spectrophotometry, chromatography, and electrophoresis. Besides its use as a safe, natural food additive with multiple functions, vanillin can be used as a plant growth promoter, fungicide, lubricant defoamer, and an important intermediate for some synthetic drugs (Fitzgerald et al., 2003;Huang et al., 2020;Ngarmsak et al., 2006;Remaud and Akoka, 2017;Stroescu et al., 2015;Zhao et al., 2018). Moreover, it has been confirmed that the level of active antioxidant substances in the blood increases with vanillin concentration when orally administered to mice, indicating possible effects on daily health care (Tai et al., 2011). ...
Vanillin is a natural antimicrobial agent; however, there are few reports on its antifungal effect on postharvest pathogenic fungi. This study aimed to investigate the in vivo and in vitro antifungal activities of vanillin against gray mold (caused by B. cinerea) and black rot (caused by A. alternata) of cherry tomato fruit and to explain its possible mechanism of action. Vanillin strongly inhibits Botrytis cinerea and Alternaria alternata mycelial growth, spore germination, and germ tube elongation in a concentration-dependent manner (P<0.05). In vivo experiments showed that 4000 mg L⁻¹ vanillin treatment inhibited cherry tomato gray mold and black rot occurrence. Besides, intercellular electrolytes, soluble proteins, and soluble sugars leakage indicated that 50 or 100 mg L⁻¹ vanillin treatment increased Botrytis cinerea and Alternaria alternata membrane permeability. The increase of malondialdehyde and hydrogen peroxide contents confirmed that 50 or 100 mg L⁻¹ vanillin treatment damages the pathogen membranes. Importantly, vanillin treatment inhibited the pathogenicity-related enzyme activities of the two pathogens to reduce their infection ability, among them PL enzyme activity in A. alternata was most inhibited, reducing by 94.7 % at 6 h treated with 100 mg L⁻¹ vanillin. The hyphae morphology of the two pathogens changed, the mycelia were severely damaged, and the hyphae surface was deformed, shrunk, or even broken after 100 mg L⁻¹ vanillin treatment. In summary, vanillin had a substantial inhibitory effect on postharvest gray mold and black rot in cherry tomato fruit. Therefore, vanillin can be an effective alternative to prevent and control cherry tomato postharvest diseases
... One of the best-known aromatic compounds is vanillin (4-hydroxy-3-methoxybenzoic acid) that is used for its sweet and appealing aroma. In addition, vanillin has antimicrobial activities and can be used as preservative (Fitzgerald et al., 2003(Fitzgerald et al., , 2004Fig. 6 Metabolism of vanillin and vanillic acid in fungi. ...
Aromatic compounds have multiple applications and are used in food and beverages, cosmetics, perfumes, plastics, pharmaceuticals, etc. Aromatic compounds are found everywhere and the degradation of aromatic compounds is essential for microorganism to survive in their environment since many of these compounds are toxic. The study of aromatic metabolism is important for the development of biotechnological processes that can give rise of new or valuable compounds. In this article examples of aromatic compounds degraded by fungi are given.
... The high amount of bioactive compounds in the seeds contributed to its high DPPH (62-72%), ABTS (0.026-0.072 mmol/g), and FRAP (0.15-0.68 mmol Fe 2+ /g) abilities, which were proven by the strong correlation between total phenolic content with DPPH and FRAP (r = 0.965 and r = 0.951, respectively) [54]. Moreover, the high flavor and volatile compounds in the leaf EOs could offer antioxidant [137], antifungal [138] and antibacterial [139] effects in medicine when utilized as a flavorer, fragrance enhancer, antimicrobial agent, and food preservative for pulses, grains, cereals, fruits, and vegetables in the food industry [140]. Meanwhile, M. alba seed oil could be a good source of tocopherol and essential fatty acids, especially linoleic acid, an omega-6 PUFA usable as a blood-vessel cleaner to decrease serum cholesterol and inhibit arterial thrombosis formation [141]. ...
Morus alba L. (M. alba) is a highly adaptable plant that is extensively incorporated in many traditional and Ayurveda medications. Various parts of the plant, such as leaves, fruits, and seeds, possess nutritional and medicinal value. M. alba has abundant phytochemicals, including phenolic acids, flavonoids, flavonols, anthocyanins, macronutrients, vitamins, minerals, and volatile aromatic compounds, indicating its excellent pharmacological abilities. M. alba also contains high nutraceutical values for protein, carbohydrates, fiber, organic acids, vitamins, and minerals, as well as a low lipid value. However, despite its excellent biological properties and nutritional value, M. alba has not been fully considered as a potential functional food ingredient. Therefore, this review reports on the nutrients and bioactive compounds available in M. alba leaves, fruit, and seeds; its nutraceutical properties, functional properties as an ingredient in foodstuffs, and a microencapsulation technique to enhance polyphenol stability. Finally, as scaling up to a bigger production plant is needed to accommodate industrial demand, the study and limitation on an M. alba upscaling process is reviewed.
... Vanillin was selected in this study as it is the main component of natural vanilla, which is among the most important and popular flavoring substances used in food industries, confectionery products, and also used as a perfume (Anuradha, Shyamala, & Naidu, 2013;Walton, Narbad, Faulds, & Williamson, 2000). Vanillin also displays antioxidant properties (Zhao, Sun, et al., 2017), anticarcinogenic effects (Durant & Karran, 2003), antimutagenic property (Bythrow, 2005), and antimicrobial properties, so it has a food preservative effect (Fitzgerald, Stratford, & Narbad, 2003). The vanillin flavor intensity can be greatly affected by many factors such as moisture, temperature, pH value (Frenkel & Havkin Frenkel, 2006;Kan et al., 2017). ...
This study aimed to investigate 4D changes in colors and flavors of 3D-printed healthy food products in response to an external or internal pH stimulus. The formulations obtained by 3D printing of multi-smart materials, comprised of the combination of red cabbage juice, vanillin powder, potato starch and different fruit juices were used. 3D printing ability of red cabbage juice and vanillin powder affected by different potato starch concentrations was first studied. Then, changes in color, texture, flavor (by E-nose) and taste (by E-tongue) induced by the stimulus were determined. Results revealed that the color of the 3D-printed product changed from blue (control sample) to red, purple, violet, blue, blue-green, and green-yellow colors when sprayed with pH solutions of 2, 3-4, 5-6, 7, 8-9, and 10, respectively. In addition, clear differences in aroma and taste profiles among pH samples were detected. Moreover, dried 4D product samples exhibited color and anthocyanins stability when stored in ambient temperature for three weeks. This study is important for manufacturing new healthy 3D-printed food products with desired and attractive sensory characteristics, which can be particularly significant to people with poor appetite.
Over the years, bacterial infections have become a threat to global health and the economy. In response to this, there has been the development of various antibacterial drugs. Increased use of such antibacterial drugs has resulted in the genetic drift within the microbial body, leading to the development of multi-drug-resistant strains (MDR) and anti-microbial-resistance strains (AMR), or super bacteria. Therefore, it is required to address this problem by developing a suitable alternative to eliminate such antibiotic resistive species and also by designing nanomaterial assisted antibiotic loading mechanisms. For which material science has come up with the gradual development of effective nanostructures such as zeolitic imidazolium framework-8 (ZIF-8), a sub-class of ZIF-metal organic framework (MOF), which has rooted as an operative antibacterial alternative because of its metal reservoir, higher surface area, tunable pore size, strong thermal stability, and biocompatibility. This review summarizes the current advancements of ZIF-8, different synthesis strategies, and their modification with different metals, metal oxides, noble metals, polymers, and antibiotics to enhance their performance towards antibacterial action on Gram-stained bacteria (positive and negative). This article also highlights some strategies to improve the antibacterial effect while acting synergistically. In addition to this, there is a prospect of future research direction of ZIF-8 based nanomaterials towards different antibacterial assays.
Graphical Abstract
The process of preprocessing techniques such as acid and alkali pretreatment in lignocellulosic industry generates substantial solid residues and lignocellulosic pretreatment wastewater (LPW) containing glucose, xylose and toxic byproducts. In this study, furfural and vanillin were selected as model toxic byproducts. Kurthia huakuii as potential strain could tolerate to high concentrations of inhibitors. The results indicated that vanillin exhibited a higher inhibitory effect on K. huakuii (3.95 % inhibition rate at 1 g/L than furfural (0.45 %). However, 0.5 g/L vanillin promoted the bacterial growth (−2.35 % inhibition rate). Interestingly, the combination of furfural and vanillin exhibited antagonistic effects on bacterial growth (Q<0.85). Furfural and vanillin could be bio-transformed into less toxic molecules (furfuryl alcohol, furoic acid, vanillyl alcohol, and vanillic acid) by K. huakuii, and inhibitor degradation rate could be promoted by expression of antioxidant enzymes. This study provides important insights into how bacteria detoxify inhibitors in LPW, potentially enhancing resource utilization.
Vanillin, a highly regarded flavor compound, has earned widespread recognition for its natural and aromatic qualities, piquing substantial interest in the scientific community. This comprehensive review delves deeply into the intricate world of vanillin synthesis, encompassing a wide spectrum of methodologies, including enzymatic, microbial, and immobilized systems. This investigation provides a thorough analysis of the precursors of vanillin and also offers a comprehensive overview of its transformation through these diverse processes, making it an invaluable resource for researchers and enthusiasts alike. The elucidation of different substrates such as ferulic acid, eugenol, veratraldehyde, vanillic acid, glucovanillin, and C6–C3 phenylpropanoids adds a layer of depth and insight to the understanding of vanillin synthesis. Moreover, this comprehensive review explores the multifaceted applications of vanillin within the food industry. While commonly known as a flavoring agent, vanillin transcends this role by finding extensive use in food preservation and food packaging. The review meticulously examines the remarkable preservative properties of vanillin, providing a profound understanding of its crucial role in the culinary and food science sectors, thus making it an indispensable reference for professionals and researchers in these domains.
The oils that are essential are highly concentrated herbal extracts from extremely significant botanicals. Popularly these oils are used in complementary and substitute medicine. The oil is usually extracted from flowers, leaves, roots, and added parts of plants. The antimicrobial activity of essential oils and their components has been studied for a very long time. Essential oils are produced from a complex combination of unstable atoms that are delivered by the optional digestion of sweet-smelling and medicinal plants and can be produced by various techniques, including distillation or microwaves. The huge number of studies on the antimicrobial action of essential oils has permitted the logical acknowledgment of these mixtures on the control of a wide scope of microbial microorganisms. The advances made on the examination of the method of activity of essential oils against bacterial cell targets give us new points of view to battle constant and antimicrobial safe bacterial microorganisms.
هدف البحث وفي اول دراسة من نوعها في مجال تكنولوجيا انتاج البيض وذلك من خلال استخدام مستويات مختلفة لنوعين من النكهات الغذائية في العليقة هي الفانيلا والبرتقال فضلا عن تحسين بعض الصفات الانتاجية للسمان الياباني. اجري البحث الحقلي في كلية الزراعة في ابو غريب / جامعة بغداد للمدة من 23 / 9 / 2016 ولغاية 30 / 12 /2016 . إذ تم تربية اناث طائر السمان الياباني بعمر 30 يوم في اقفاص . واستخدام نوعين من النكهات الغذائية الصناعية(نكهة الفانيلا و نكهة البرتقال) بهيئة مسحوق اسباني المنشأ. تم شرائها من الاسواق التجارية الواقعة في منطقة الشورجة / بغداد. وتم تقسيم المعاملات الى خمسة معاملات بواقع مكررين لكل المعاملة : الاولى: معاملة السيطرة (بدون اضافة). الثانية : اضافة 1% نكهة الفانيلا الى العليقة. الثالثة: اضافة 0.5% نكهة فانيلا الى العليقة . الرابعة: اضافة 1% نكهة البرتقال الى العليقة . الخامسة: اضافة 0.5% نكهة البرتقال الى العليقة . إذ بينت نتائج التحليل الاحصائي للصفات الانتاجية وجود فروق عند مستوى معنوية (P<0.01) والتي بينت تفوق كلا المعاملتين الثانية والخامسة وتلتها المعاملة الثالثة والرابعة في حين سجلت المعاملة الاولى اوطئ القيم في صفات نسبة انتاج البيض ومعدل وزن البيضة وانتاج البيض التراكمي وكتلة البيض المنتج وكفاءة التحويل الغذائي خلال الفترات الثلاثة الاخيرة من الدراسة. نستنتج امكانية اضافة نسب 0.5 او 1 % من المنكهات الغذائية التجارية للعلف لتحسن عدد كبير من الصفات الانتاجية للسمان الياباني.
Vanillin is a potent growth-inhibiting factor in Saccharomyces cerevisiae during lignocellulose biorefineries. Here, a haploid gene-deletion library was screened to search for vanillin-tolerant mutants and explain the possible tolerance mechanisms. Twenty-two deletion mutants were identified. The deleted genes in these mutants were involved in phosphate and inositol polyphosphate metabolism and intracellular sterol transport. Activation of the phosphate signaling pathway is not conducive to yeast against the pressure of vanillin. Furthermore, the findings indicate the role of inositol polyphosphates in altering vanillin tolerance by regulating phosphate metabolism. Meanwhile, reducing the transport of sterols from the plasma membrane enhanced tolerance to vanillin. In the presence of vanillin, the representative yeast deletions, pho84Δ and lam3Δ, showed good growth performance and promoted rapid ethanol production. Overall, this study identifies robust yeast strain alternatives for ethanol fermentation of cellulose and provides guidance for further genomic reconstruction of yeast strains.
Background
Volatile oils and their constituents have been considered as major bioactive natural compounds due to their wide therapeutic and biological activities in the field of pharmaceuticals in human healthcare. However, due to their poor solubility, their applications are limited. Inclusion complexation of volatile oils and their volatile constituents with cyclodextrins has emerged as a promising approach for the improvement of aqueous solubility, bioavailability, and stability.
Objective
The present review summarizes various research investigations highlighting the complexation of volatile oils and their constituents with cyclodextrins and their derivatives. Additionally, we present the glimpses of patents published between 1998-2021to highlight the significance of inclusion of volatile oil in cyclodextrins.
Methods
The selection of articles for the current review was carried out by using keywords ‘Cyclodextrin’, ‘Essential oil’, ‘Inclusion Complex’, ‘Encapsulation’ and ‘Essential oils/ volatile oils constituents’ in certain specific databases such as Elsevier (Science direct), Pubmed Medical subject headings (MeSH) and Medline.
Result
199 studies published were included in the review. Invitro and invivo studies revealed the efficacy of EOs and their VCs complexed with various types of CD when compared to free forms.
Conclusion
This review shows the impact of cyclodextrin complexation on the solubility, bioavailability, stability, and biological activities of volatile oils and their constituents.
Vanillin ― a bioactive substance to interfere various biological activities ― is reportedly able to mitigate fouling in a membrane bioreactor (MBR). However, impact of continuous dose of vanillin on treatment performance and microbial activities in MBR are still unknown. In this study, effects of vanillin on production of extracellular polymeric substances (EPS) and microbial community was investigated in lab-scale MBR under continuous dose of vanillin. Vanillin dose remarkably reduced membrane fouling in accordance with less development of cake layer. It was probably because bulk sludge contained more hydrophilic components and became less adhesive by lower abundance of Xanthomonadaceae and Chitonophagaceae, which are known to produce viscous EPS and hydrophobic lipopolysaccharides. In addition, filtration resistance of cake layer was probably reduced by less contents of SMP and LB-EPS due to inhibition of Flavobacterium and Xanthomonadaceae, which are biofilm forming bacteria and EPS producers. These results suggest that interference to microbial activity by continuous dose of vanillin alters characteristics of sludge EPS, thus effectively mitigate biofouling in MBR.
Vanillin is used as a flavor ingredient in a diverse range of food categories and is known to inhibit microbial fermentation. In this study, we found that vanillin improved the hydrophobic organic solvent tolerance of Escherichia coli and showed that the AcrAB-TolC efflux pump is implicated in that tolerance. The expression level of the pump was enhanced by the addition of vanillin. AcrAB-TolC efflux pump expression is known to be regulated by transcription activators such as MarA, SoxS, and Rob. Among these three transcription factors, marA transcription was significantly elevated by the addition of vanillin. We found that the AcrAB-TolC efflux pump is involved also in vanillin tolerance. The ΔacrB mutant was more sensitive to vanillin than the parent strain. A complementation test revealed that the introduction of the acrB gene recovered the vanillin tolerance of the ΔacrB mutant.
Equilibrium mole fraction solubility of vanillin in nine aqueous-ethanolic mixtures, as well as in neat water and neat ethanol, was determined at seven temperatures from T = 293.15 to T = 323.15 K. Vanillin solubility in these mixtures was adequately correlated with several well-known correlation models with the mean percentage deviations of 5.9 to 18.3%. Respective apparent thermodynamic functions, i.e. Gibbs energy, enthalpy, and entropy, for the dissolution, mixing and solvation processes, were computed using the van’t Hoff and Gibbs equations. The enthalpy–entropy relationship for vanillin was non-linear in the plot of enthalpy vs. Gibbs energy of dissolution with positive slopes from neat water to the mixture of w1 = 0.10 and the interval 0.50 < w1 < 0.90 but negative in the interval 0.10 < w1 < 0.50 and from w1 = 0.90 to neat ethanol. Accordingly, in the first cases the vanillin transfer from more polar to less polar solvent systems is enthalpy-driven but entropy-driven for the last ones. Moreover, by means of the inverse Kirkwood-Buff integrals is observed that vanillin is preferentially solvated by water molecules in water-rich mixtures but preferentially solvated by ethanol molecules in mixtures of 0.23 < x1 < 1.00.
To address the serious threat of bacterial infection to public health, great efforts have been devoted to the development of antimicrobial agents for inhibiting bacterial growth, preventing biofilm formation, and sterilization. Very recently, metal-organic frameworks (MOFs) have emerged as promising materials for various antimicrobial applications owing to their different functions including the controlled/stimulated decomposition of components with bactericidal activity, strong interactions with bacterial membranes, and formation of photogenerated reactive oxygen species (ROS) as well as high loading and sustained releasing capacities for other antimicrobial materials. This review focuses on recent advances in the design, synthesis, and antimicrobial applications of MOF-based materials, which are classified by their roles as component-releasing (metal ions, ligands, or both), photocatalytic, and chelation antimicrobial agents as well as carriers or/and synergistic antimicrobial agents of other functional materials (antibiotics, enzymes, metals/metal oxides, carbon materials, etc.). The constituents, fundamental antimicrobial mechanisms, and evaluation of antimicrobial activities of these materials are highlighted to present the design principles of efficient MOF-based antimicrobial materials. The prospects and challenges in this research field are proposed.
Soil microbial production of indolic and phenolic compounds derived from aromatic amino acids is regarded as an important factor in plant development. Plant growth was promoted upon the addition of L-tryptophan (Trp) to soil (Frankenberger et al. 1990; Frankenberger and Arshad 1991a,b). Environmental fluctuations cause increased Trp contents in soil and regulate the microbial production of indole-3-acetic acid (auxin), of its storage product indole-3-ethanol, and of anthranilic acid from the precursor Trp (Lebuhn et al. 1994). Microbial auxin and indole-3-ethanol exert auxin-phytohormone effects on plants (Martin et al. 1989; Müller et al. 1989; Selvadurai et al. 1991). Auxin also seems to control the induction of plant resistance mechanisms (Jouanneau et al. 1991).
A simple presence-absence test for detection of small numbers of osmotolerant yeasts in foods was developed. Yeast extract glucose 50 broth [consisting of 0.5% (w/w) yeast extract and 50% (w/w) glucose] was used as enrichment medium and was incubated with agitation at 30°C. The detection was done by (a) microscope and (b) streaking 0.03 ml of enrichment culture on selective yeast extract glucose 50 agar and incubation at 30°C for 5–7 d. If no yeast cells were observed under the microscope within 10 d of incubation, the product sample was judged as “free from osmotolerant yeasts.” In accordance with this method 28 strains of osmotolerant yeasts were isolated from 27 spoiled high-sugar products. Twenty-four strains were identified as Zygosaccharomyces rouxii, 2 Zygosaccharomyces bailii and 1 each as Torulaspora delbrueckii and Debaryomyces hansenii.
Yogurt samples purchased from a dairy industry, retail outlets, and hawkers in Lagos, Nigeria, were plated on potato dextrose agar containing 100 μg of chloramphenicol/ml and found to contain Candida lusitaniae, C krusei, C rugosa, Kluveromyces fragilis, and Saccharomyces cerevisiae as the primary yeast contaminants. Sixty-seven percent of the samples had yeast counts in the range of 104–106 cfu/ml. C. lusitaniae, K. fragilis and C. krusei had the highest counts and occurrence of 65, 48 and 51%, respectively, in 100 random yogurt samples. C. lusitaniae attained the highest count in yogurts stored at 10°C and C. krusei in those at 30°C.
Ninety percent of the samples had less than 10 coliforms or staphylococci per ml, whereas 20% had over 103 psychrotrophic bacteria per ml. Molds of Aspergillus sp. and Neurospora sp. were isolated mainly from the strawberry-fluid yogurt. The starter cultures, Lactobacillus bulgaricus and Streptococcus thermophilus, were present in the ratio of 1:1 and reached maximum growth levels of 107 to 108 cfu/ml after 4 to 8 d of storage at 10°C, whereas the yeast continued to increase beyond this level by the 12th day. The extent of contamination observed suggests high initial contamination level and improper refrigeration of yogurts marketed.
Populations and frequency of occurrence of yeasts in frozen apple, cherry, grape, orange, and pineapple juice concentrates were determined. Total yeast populations ranged from log10 < 1.00 to 5.41 CFU/ml of diluted (1:4) concentrate and increased to 2.42–7.34 CFU/ml after 24 h of incubation at 25°C. One hundred fifty-four isolates from 33 samples of fruit juice concentrates represented 21 species and 12 genera. The most frequently isolated species were Saccharomyces cerevisiae (24.7% of isolates), Candida stellata (22.1%), and Zygosaccharomyces rouxii (14.3%), followed by, in decreasing order of frequency, Torulaspora delbrueckii, Rhodotorula mucilaginosa, Issatchenkia orientalis, Hanseniaspora occidentalis, Lodderomyces elongisporus, Kluyveromyces thermotolerans, Hanseniaspora guilliermondii, Candida glabrata, and Pichia anomala, each representing 3–8% of isolates. Candida magnoliae, Candida maltosa, Candida parapsilosis, Candida tropicalis, Clavispora lusitaniae, Cryptococcus humicolus, C. laurentii, Pichia membranaefaciens, and Sporidiobolus salmonicolor were represented by single isolates. Populations in various samples consisted of 24–100% S. cerevisiae, 52–100% C. stellata, and 3–56% for Z. rouxii. S. cerevisiae and Z. rouxii were isolated, respectively, from five and four types of fruit concentrates investigated. This may be the first observation of this high frequency of C. stellata in juice concentrates.
The wide range of extremely effective naturally occurring antimicrobial systems include those derived from animals (e.g., enzymes such as lysozyme and lactoperoxidase; other proteins such as lactoferrin, lactoferricin, ovotransferrin, and serum transferrins; small peptides such as histatins and magainins; and the immune system), those derived from plants (e.g., phytoalexins, low- molecular-weight components of herbs and spices; phenolics such as oleuropein; and essential oils) and those derived from microorganisms (e.g., bacteriocins such as nisin and pediocin). An increasing number of such natural systems is being deliberately utilized for food preservation, or being explored for such use. The future potential is substantial, particularly as the efficacy of these systems is demonstrated in additive or synergistic combinations with some of the other antimicrobial factors that we can employ to improve the safety and shelf stability of foods. While "naturalness" alone is not necessarily a sufficient objective for these developments, the use of natural inhibitors as components of systems that can together enhance the effectiveness of preservation, with advantages in product quality and safety, justifies pursuit. Copyright ©, International Association of Milk, Food and Environmental Sanitarians.
The water and ethanol extracts of several commercially available spices were examined for their inhibitory action on the decarboxylase activity of a crude extract of Enterobacter aerogenes. The water extracts had a negligible effect on histidine decarboxylase activity, except for water extract of cloves which reduced the activity by about 40%. However, the ethanol extracts had a rather higher inhibitory action upon histidine, lysine, and ornithine decarboxylases. Of the spices used, cloves, cinnamon, sage, nutmeg, and allspice were very effective in inhibiting the decarboxylases. Among the components of those spices, cinnamaldehyde and eugenol were found to be effective inhibitors.
The viable counts of Salmonella typhimurium on nutrient agar (NA) decreased upon the addition of either the essential oil of thyme or its constituent thymol, especially under anaerobic conditions. Antagonistic effects of thymol against Staphylococcus aureus were also greater under anaerobic conditions. In contrast to the phenolic constituents of the oil, thymol and carvacrol, the chemically related terpenes p ‐cymene and y ‐terpinene had no antagonistic effects against Salm. typhimurium.
The addition of Desferal to NA counteracted the antibacterial effects of both thyme oil and thymol. No support was obtained, however, for a possible role of iron in the oxygen‐related antibacterial action of the thyme oil and thymol or for the observed effect of Desferal. In the presence of thymol, the viable counts of Salm. typhimurium obtained on a minimal medium (MM) were lower than those obtained on NA. Addition of bovine serum albumin (BSA) neutralized the antibacterial action of thymol. It is suggested that the effects of BSA or Desferal are due to their ability to bind phenolic compounds through their amino and hydroxylamine groups, respectively, thus preventing complexation reactions between the oil phenolic constituents and bacterial membrane proteins. This hypothesis is supported by the marked decrease in the viable counts of Salm. typhimurium caused by either thyme oil or thymol when the pH of the medium was changed from 6.5 to 5.5 or the concentration of Tween 80 in the medium was reduced.
Refrigerated ready-to-eat foods are becoming increasingly popular but are often vulnerable to contamination and subsequent growth by psychrotrophic foodborne pathogens. Consequently, there is a need for additional methods to assure the safety of these foods. Beef slices prepared from roasted whole sirloin tips were used in the study. Nine plant extracts were evaluated for ability to inhibit the growth of two psychrotrophic pathogens (Aeromonas hydrophila and Listeria monocytogenes) in refrigerated cooked beef. Results indicated that only eugenol (clove extract) and pimento extract significantly inhibited the growth of A. hydrophila and L. monocytogenes. However, L. monocytogenes was not as sensitive as was A. hydrophila to both treatments, especially to pimento extracts. These results suggest that plant extracts might be useful as an antimicrobial in cooked ready-to-eat meat.
The individual and combined effects of potassium sorbate and vanillin concentrations on the growth of Penicillium digitatum, P. glabrum, and P. italicum in potato dextrose agar adjusted to water activity 0.98 and pH 3.5 were evaluated. Inhibitory concentrations of potassium sorbate varied from 150 ppm for P. digitatum to 700 ppm for P. glabrum, and for vanillin from 1,100 ppm for P. digitatum and P. italicum and 1,300 ppm for P. glabrum. Fractional inhibitory concentration (FIC) isobolograms show curves deviated to the left of the additive line. Calculated FIC index varied from 0.60 to 0.84. FIC index as well as FIC isobolograms show synergistic effects on mold inhibition when vanillin and potassium sorbate are applied in combination.
Preservative agents are required to ensure that manufactured foods remain safe and unspoiled. In this review, we will discuss the mode of action of both chemical and biological (nature-derived) preservatives and the stress response mechanisms induced by these compounds in microorganisms of concern to the food industry. We will discuss the challenges that food manufacturers face with respect to the assurance of food safety and the prevention of spoilage. Following this, chemical preservatives will be discussed, in particular, weak organic acids such as sorbic and benzoic acid which are widely used in preservation. Furthermore. the mechanisms of microbial inactivation with hydrogen peroxide mediated systems and chelators such as citric acid and EDTA and their potential use in preservation will be covered. We will then address the potential of naturally occurring "preservatives". Of the antimicrobial compounds present in nature, first to be discussed will be the nonproteinaceous compounds often present in herbs and spices and we will speculate on the stress response(s) that microorganisms may elicit to these natural compounds. Next to be addressed will be compounds that attack cell walls and membranes, for example, peptides, proteins and lytic enzymes. In discussing the resistance mechanisms against membrane and wall perturbation, the extensive knowledge of stress responses against osmotic stress and temperature stress will be refered to. Finally, in the concluding paragraphs, options for combination preservation systems are evaluated.
Overview, A.S. Naidu Lacto-Antimicrobials Lactoferrin. A.S. Naidu Lactoperoxidase, A.S. Naidu Lactoglobulins, E.F. Bostwick, J. Steijins, and S. Braun Lactolipids, M. Lampe and C. Isaacs Ovo-Antimicrobials Lysozymes, J.N. Losso, S. Nakai, and E.A. Charter Ovotransferrin, H.R. Ibrahim Ovoglobulin IgY, J.S. Sim, H.H. Sunwoo, and E.N. Lee Avidin, Y. Mine Phyto-Antimicrobials Phyto-phenols, P.M., Davidson and A.S. Naidu Saponins, W.A. Oleszek Flavonoids, A.S. Naidu, W.R. Bidlack, and A.T. Crecelius Thiosulfinates, B.B. Whitmore and A.S. Naidu Catechins, L.R. Juneja, T. Okubo, and P. Hung Glucosinolates, B.B. Whitmore and A.S. Naidu Agar, A.S. Naidu Bacto-Antimicrobials Probiotics, A.S. Naidu and R.A. Clemens Nisin, L.V. Thomas, M.R. Clarkson, and J. Delves-Broughton Pediocin, B. Ray and K. Miller Reuterin, M.G. El-Ziney, J. Debevere, and M.Jakobsen Sakacin, F. Leroy and L. De Vuyst Acid-Antimicrobials Lactic Acid, J-C. Bogeart and A.S. Naidu Sorbic Acid, J.N. Sofos Acetic Acid, D.L. Marshall, L.N. Cotton, and F.A. Bal'a Citric Acid, R.K. Sharma Milieu-Antimicrobials Sodium Chloride, R. Ravishankar and V.K. Juneja Polyphosphates, A. Prakash Chloro-cides, N. Khanna and A.S. Naidu Ozone, M. Muthukumarappin, F. Halaweish, and A.S. Naidu Appendix (Abbreviations and Symbols) Index
Biological reactions of oxidoreduction are catalyzed by special types of enzymes, the oxidoreductases, which require different cofactors. In our laboratories, we are looking for a special way to specifically reduce some compounds in inexpensive reactors. Bearing this in mind, we have studied the reduction of vanillin to vanillyl alcohol by Saccharomyces cerevisiae. Saccharomyces cerevisiae, when grown in liquid media containing carbon and nitrogen sources and vanillin, reduces this aromatic aldehyde to the corresponding alcohol, vanillyl alcohol. The identification of vanillyl alcohol has been obtained by HPLC, GCMS, RMN, and IR spectrophotometry, on purified culture media (liquid-liquid extraction). The bioconversion was optimal at 30 degree C, pH 3, in complete liquid media, with or without oxygen. An anaerobic immobilized cell reactor was set up for 150 h; cells were immobilized by inclusion in alginate beads; productivity of these reactors attained 200 g vanillyl alcohol per m**3 per day.
The effect of selected phenolic compounds on the membrane-bound ATPase activity of two strains of Staphylococcus aureus was studied. These phenolic compounds were: butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ), propyl gallate (PG), p-coumaric, ferulic, caffeic acids, methyl paraben and propyl paraben. Cytoplasmic membrane-bound ATPase activity was measured in the presence of 0, 150, 300, 600 and 1200 μg ml−1 of each phenolic compound. Among all the compounds studied, only BHA was found to significantly stimulate the activity of the enzyme. In contrast, some of the compounds were found to significantly inhibit the activity of the enzyme as was the case of TBHQ, PG, p-coumaric acid, ferulic acid and caffeic acid. The remaining compounds did not influence the activity of the ATPase at any of the concentrations tested. Strain LP ATPase as stimulated less by BHA and inhibited to a greater extent by TBHQ and PG than was the enzyme from strain A100. In contrast, LP ATPase was less inhibited by p-coumaric acid and not affected by either ferulic or caffeic acid.
The effects of incubation temperature (10–30°C), pH (3.0–4.0) and vanillin concentration (350–1200ppm) on the growth ofAspergillus flavus, Aspergillus niger, Aspergillus ochraceusandAspergillus parasiticuswere evaluated using potato–dextrose agar adjusted to water activity (aw) 0.98. The radial growth rates after a lag period followed zero-order kinetics with constants that varied from 0 (no growth) to 0.63mmh−1. The lag period depended on vanillin concentration, pH and incubation temperature. The germination time and the radial growth rates were significantly affected by the three studied variables (P
Preservative agents are required to ensure that manufactured foods remain safe and unspoiled. In this review, we will discuss the mode of action of both chemical and biological (nature-derived) preservatives and the stress response mechanisms induced by these compounds in microorganisms of concern to the food industry. We will discuss the challenges that food manufacturers face with respect to the assurance of food safety and the prevention of spoilage. Following this, chemical preservatives will be discussed, in particular, weak organic acids such as sorbic and benzoic acid which are widely used in preservation. Furthermore, the mechanisms of microbial inactivation with hydrogen peroxide mediated systems and chelators such as citric acid and EDTA and their potential use in preservation will be covered. We will then address the potential of naturally occurring “preservatives”. Of the antimicrobial compounds present in nature, first to be discussed will be the nonproteinaceous compounds often present in herbs and spices and we will speculate on the stress response(s) that microorganisms may elicit to these natural compounds. Next to be addressed will be compounds that attack cell walls and membranes, for example, peptides, proteins and lytic enzymes. In discussing the resistance mechanisms against membrane and wall perturbation, the extensive knowledge of stress responses against osmotic stress and temperature stress will be refered to. Finally, in the concluding paragraphs, options for combination preservation systems are evaluated.
Ethanol production, respiration, and sporulation of yeasts as effected by essential oils and oleoresins of allspice, cinnamon, clove, garlic, onion, oregano, savory, and thyme were investigated. Essential oils of allspice, cinnamon, and clove had little or no effect on ethanol production by Sacchraromyces cerevisiae. Oils of onion, oregano, savory, and thyme delayed and/or reduced the production of ethanol. Overall, essential oils effectively suppressed ethanol production by Hansenula anomala. At the highest concentrations tested (500 μg/ml), only cinnamon, clove, garlic and thyme oleoresins substantially delayed and/or reduced ethanol production by S. cerevisiae. Most of the essential oils (100 μm/ml) impaired the respiratory activity of S. cerevisiae as evidenced by a reduction in CO2 production. Thyme oleoresin was the strongest inhibitor. Allspice and garlic oils impaired sporulation by H. anomala. All oils delayed sporulation of Lodderomyces elongisporus).
Separation of the lignin component of wood from the cellulose presents an opportunity to access various interesting products from the lignin fragments. The lignin represents availability of a sizable renewable resource. Vanillin, or 3-methoxy-4-hydroxybenzaldehyde, is one of a series of related substituted aromatic flavor constituents, and represents one of the potentially profitable possibilities. Vanillin production from the lignin-containing waste liquor obtained from acid sulfite pulping of wood began in North America in the mid 1930's. By 1981 one plant at Thorold, Ontario produced 60% of the contemporary world supply of vanillin. The process also simultaneously decreased the organic loading of the aqueous waste streams of the pulping process. Today, however, whilst vanillin production from lignin is still practiced in Norway and a few other areas, all North American facilities using this process have closed, primarily for environmental reasons. New North American vanillin plants use petrochemical raw materials. An innovation is needed to help overcome the environmental problems of this process before vanillin production from lignin is likely to resume here. Current interest in the promotion of chemicals production from renewable raw materials reinforces the incentive to do this. Keywords (Audience): General Public
Of 21 food flavoring compounds tested against 39–40 organisms, 10 were ineffective at 1,000 ppm or 10 mM either at pH 6 or 8 and by either surface plating or in broth. The 11 effective compounds were d- and l-carvone, diacetyl, ethyl vanillin, eugenol, maltol, menthol, phenylacetic acid, phenylacetal-dehyde, 2,3-pentanedione and vanillin; with diacetyl and eugenol being the most effective. All were more effective at pH 6 than at pH 8. With the exception of maltol and phenylacetic acid, each was generally more effective against fungi than bacteria with the lactic acid bacteria being the most resistant. At pH 5.5 and 5°C, diacetyl was inhibitory to Pseudomonas fluorescens and P. geniculata at < 10 ppm. The findings suggest that compounds used in acid foods, ostensibly as flavoring agents, may exert antimicrobial effects when considered in context with all parameters of growth.
Brettanomyces anomalus is shown here to metabolise p-coumaric, caffeic and ferulic acid to 4-vinyl and 4-ethyl derivatives. We also demonstrate the transformation of vanillin to both vanillyl alcohol and vanillic acid by this yeast. The results presented here show the production of these compounds during the fermentation of this organism and also the effects of these and other simple phenolic compounds on the growth of the organism. The products were analysed and their identities were determined by TLC, HPLC and by mass spectrometry.
Vanillin is probably the most widely used flavouring agent for sweet foods such as biscuits, desserts, ice cream etc. It has been argued, however, that vanillin is used not only as a flavouring ingredient but also to mask undesirable off-flavours developed during storage by products susceptible to oxidative degradation.
This paper shows that vanillin not only adds its pleasant flavour note, but also acts as an antioxidant in complex foods containing polyunsaturated fatty acids. It is shown that the keeping quality of precooked dried cereal flakes was considerably increased by the addition of 0·01–0·5% (on a dry matter basis) of vanillin.
The utilization of vanillin was studied as a natural antimicrobial in a combined technology for producing a shelf-stable strawberry purée. Mild heat treatment (blanching) was combined with addition of 3,000 ppm vanillin and 500 ppm ascorbic acid and adjustment of water activity (aw) to 0.95 and pH to 3.0. This prevented growth of both native and inoculated flora for ≥60 days storage at room temperature.
The combined effects of pH (3.0–4.0) and vanillin concentration (500–1,000 ppm) on the growth of Aspergillus flavus, A. niger, A. ochraceus and A. parasiticus were evaluated in potato-dextrose agar adjusted to a water activity 0.98. Mold germination time and radial growth rates (RGR) were significantly affected by the variables (p<0.05). For equal concentration of the antimicrobial the reduction in pH had important effects lowering the RGR. The lag time increased as vanillin concentration increased and pH decreased. The inverse lag times of each mold could be described by second order polynomials.
One of the next challenges in the use of biocatalysts (enzyme or microbial cells) is the upgrading of biological reactions of oxidoreduction. The oxidoreductases need cofactors that must be regenerated. Practical experience shows that this is most readily achieved by using living cells of microorganisms.
Living cells ofSaccharomyces cerevisiae are able to bioconvert vanillin to vanillyl alcohol (1). By working with a two-phase reactor (dodecanol—feeding medium) it has been possible to use higher vanillin concentrations without inhibiting the bioconversion (2).
Several parameters, such as, volume ratio of aqueous over organic phase, pH, vanillin concentration seem to influence the bioconversion greatly. Bearing this is mind, two-phase reactors have been set up. Productivities exceeded 5000 g/m3/d.
On the other hand,Saccharomyces cerevisiae mutants have been selected as vanillyl alcohol hyperproducers: vanillyl alcohol productivity of the best selected mutant is twice as high as wild-type strain productivity. Their specific behavior has been studied.
The inhibitory effects of various concentrations of natural vanillin on the growth of Aspergillus flavus, A. niger, A. ochraceus and A. parasiticus in laboratory media and five fruit (apple, banana, mango, papaya and pineapple)-based agars at pH 3·5 and water activity (aw) 0·98 were studied. The most resistant mould to the conditions studied was A. niger, followed by A. parasiticus, A. flavus and A. ochraceus. For each mould the increase in vanillin concentration and the type of fruit used in agar preparation significantly (P < 0·05) affected the radial growth rate. The vanillin inhibitory concentrations were in general lower than 2000 ppm. The inoculated moulds grew faster and in higher vanillin concentrations on mango and banana fruit-based agars. The lower inhibitory effect of vanillin in mango and banana agar was attributed at least partially to their fat and/or protein content.
Carvacrol, (+)-carvone, thymol, and trans-cinnamaldehyde were tested for their inhibitory activity against Escherichia coli O157:H7 and Salmonella typhimurium. In addition, their toxicity to Photobacterium leiognathi was determined, utilizing a bioluminescence assay. Their effects on the cell surface were investigated by measuring the uptake of 1-N-phenylnaphthylamine (NPN), by measuring their sensitization of bacterial suspensions toward detergents and lysozyme, and by analyzing material released from cells upon treatment by these agents. Carvacrol, thymol, and trans-cinnamaldehyde inhibited E. coli and S. typhimurium at 1-3 mM, whereas (+)-carvone was less inhibitory. trans-Cinnamaldehyde was the most inhibitory component toward P. leiognathi. Carvacrol and thymol disintegrated the outer membrane and released outer membrane-associated material from the cells to the external medium; such release by (+)-carvone or trans-cinnamaldehyde was negligible. Of the tested components, carvacrol and thymol decreased the intracellular ATP pool off. coli and also increased extracellular ATP, indicating disruptive action on the cytoplasmic membrane.
The effect of vanillin and essential oil of mint on the growth of different strains of food spoilage yeasts in laboratory media and fruit purées was studied. Growth of Saccharomyces cerevisiae, Zygosaccharomyces rouxii, Debaryomyces hansenii and Z. bailii was inhibited in culture media and apple purée containing 2000 ppm of vanillin for 40 days storage at 27 degrees C and a(w) 0.99 or 0.95. But 3000 ppm of the spice were not effective to inhibit Z. bailii growth in banana purée. Growth of yeasts was not affected by 100 ppm of essential oil of mint.
Carvacrol, a natural plant constituent occurring in oregano and thyme, was investigated for its bactericidal effect towards the food-borne pathogen Bacillus cereus. Carvacrol showed a dose-related growth inhibition of B. cereus. At concentration of 0.75 mmol l-1 and above, total inhibition of the growth was observed. Below this concentration, carvacrol extended the lag-phase, reduced the specific growth rate and reduced the maximum population density. Incubation for 40 min in the presence of 0.75-3 mmol l-1 carvacrol decreased the number of viable cells of B. cereus exponentially. Spores were found to be approximately 2-3 fold less sensitive to carvacrol than vegetative cells. Bacillus cereus cells showed reduced susceptibility towards carvacrol at pH 7.0 compared with different values between pH 4.5 and 8.5. The culture and exposure temperatures had a significant influence on the survival of vegetative cells. The highest death rate of cells was observed at an exposure temperature of 30 degrees C. Membrane fluidity was found to be an important factor influencing the bactericidal activity of carvacrol.
Carvacrol, a naturally occurring compound mainly present in the essential oil fraction of oregano and thyme, was studied for its effect on bioenergetic parameters of vegetative cells of the food-borne pathogen Bacillus cereus. Incubation for 30 min in the presence of 1 to 3 mM carvacrol reduced the viable cell numbers exponentially. Carvacrol (2 mM) significantly depleted the intracellular ATP pool to values close to 0 within 7 min. No proportional increase of the extracellular ATP pool was observed. Depletion of the internal ATP pool was associated with a change of the membrane potential (Deltapsi). At concentrations of 0.01 mM carvacrol and above, a significant reduction of Deltapsi was observed, leading to full dissipation of Deltapsi at concentrations of 0.15 mM and higher. Finally, an increase of the permeability of the cytoplasmic membrane for protons and potassium ions was observed (at 0.25 and 1 mM carvacrol, respectively). From this study, it could be concluded that carvacrol interacts with the membranes of B. cereus by changing its permeability for cations like H(+) and K(+). The dissipation of ion gradients leads to impairment of essential processes in the cell and finally to cell death.
Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. Since about 20 years the intelligent application of hurdle technology became more prevalent, because the principles of major preservative factors for foods (e.g., temperature, pH, a(w), Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behaviour of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multitarget food preservation emerged. In the present contribution a brief introduction is given on the potential hurdles for foods, the hurdle effect, and the hurdle technology. However, emphasis is placed on the homeostasis, metabolic exhaustion, and stress reactions of microorganisms related to hurdle technology, and the prospects of the future goal of a multitarget preservation of foods.
Antimicrobials occurring nat-urally in foods
- L R Beuchat
- D A Golden
Beuchat, L.R., Golden, D.A., 1989. Antimicrobials occurring nat-urally in foods. Food Technol. 43, 134 – 142.