Article

Use of tannins to enhance the functional properties of protein based films

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

In this study, three tannins from different sources have been used (from white peel grape (W), red peel grape (R) and from oak bark (O)) to obtain active films based on proteins (caseinate and gelatin) on the basis of their natural origin and potential antioxidant and antimicrobial activity. Films were obtained in two different ways: monolayer films, by homogeneously blending the tannins with the proteins and bilayer films, by coating the previously obtained protein film with the different tannin solutions. The microstructural, physicochemical characterisation as well as the antioxidant and antimicrobial activities of the films were analysed. The interactions developed between tannins and protein matrices determined the physico-chemical properties of the films. Significant changes were only observed in tannin-caseinate films, due to the establishment of hydrogen bonding and hydrophobic interactions, especially when using the tannin with the greatest phenolic content (W). Thus, the W tannin caseinate based films turned thicker, with markedly improved (p < 0.05) water solubility and WVP values and became mechanically stiffer and less stretchable. All of the films incorporating tannins exhibited remarkable antioxidant and antimicrobial activities against E.Coli and L. innocua, being the bilayer films containing W tannin the ones exhibiting the best antioxidant and antimicrobial activity against both bacteria (5 log of reduction), due to the greater availability of the active component when incorporated as a bilayer.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Tea polyphenols contain catechins, mono-and digallates, theaflavin, flavones, tannins, anthocyanins and phenolic acid and demonstrate high antioxidant and antimicrobial properties [162][163][164]. Tannins can be obtained from wood, leaves, stems and seeds [165]. Cocoa beans and green algae are good sources of procyanidins, catechins and its compounds [166,167]. ...
... Individual plant compounds are actively used to improve the physico-chemical, structural-mechanical, barrier and organoleptic properties of biopolymer films as well as enrich them in active properties-antimicrobial and antioxidant ( Table 1). The film thickness increased with the addition of individual plant compounds, which is explained by the higher content of solids in the packaging material [165,187,189]. Interestingly, addition of monolaurin and eugenol to zein film led to the reduction in thickness due to the surfactive properties of monolaurin and good distribution in the FFS. ...
... The surface and structure of the films were different depending on the binding or crosslinking and distribution of the active components. Some films had cracks and voids [165,182,183], while others were smooth and even [186,188]. MC was reduced in active films [165,188]. ...
Article
Full-text available
The global trend towards conscious consumption plays an important role in consumer preferences regarding both the composition and quality of food and packaging materials, including sustainable ones. The development of biodegradable active packaging materials could reduce both the negative impact on the environment due to a decrease in the use of oil-based plastics and the amount of synthetic preservatives. This review discusses relevant functional additives for improving the bioactivity of biopolymer-based films. Addition of plant, microbial, animal and organic nanoparticles into bio-based films is discussed. Changes in mechanical, transparency, water and oxygen barrier properties are reviewed. Since microbial and oxidative deterioration are the main causes of food spoilage, antimicrobial and antioxidant properties of natural additives are discussed, including perspective ones for the development of biodegradable active packaging.
... It is well known that phenolic compounds such as tannins have a significant binding affinity to proteins and that these interactions can result in different structural modifications. These can modify the final properties of protein-based products, such as water repellence (Cano, Andres, Chiralt, & González-Martinez, 2020). The binding is dependent on the type of protein and the diverse structures of the phenolic compounds (Jakobek, 2015). ...
... Furthermore, solubility, colour retention, extract release during immersion and antioxidant activity of the released extracts, along with the colour change capacity of the films to external direct and indirect pH stimuli, were examined. To the best of our knowledge, limited studies (Cano et al., 2020) have been reported on the utilisation of tannins for both the modification of proteins such as gelatin films as well as the development of gelatin-based active and/or intelligent packaging systems. ...
... This was related to more phenolic compounds in the latter extract, as seen in Fig. 1 e and f, and Table S1. The antioxidant properties of the extracts, especially SeedT, showed that these compounds could be used for antioxidant (active) film development (Cano et al., 2020;Riahi, Priyadarshi, Rhim, & Bagheri, 2021). ...
Article
Full-text available
To achieve sustainability in the wine industry, by-products from winery operations are being diverted from waste streams and turned into beneficial use. Grape seed tannin (SeedT) and skin tannin (SkinT) extracts were used to modify the properties of gelatin films, and to prepare active/intelligent films. The SeedT extract showed a higher phenolic content (~ 440 mg gallic acid (GA)/g extract) and antioxidant inhibition (~ 20 %) than the SkinT extract (14 mg GA/g extract, 2 % antioxidant inhibition), while both extracts presented colour variations with an increase of solution pH. The addition of extracts into the gelatin formulation resulted in coloured and transparent films with lower wettability (water contact angle increased up to 92°) and higher UV-light absorbance (secondary antioxidant function) properties. The films were capable of releasing tannins by up to 20 % which led to antioxidant inhibition values of up to 13 % (primary antioxidant function). The addition of SkinT tannins into the films provided the films with a pH indicator ability (intelligent function).
... Indeed, extract quality, extraction rate, final cost, extraction yield, consumer, and environmental protection are some determining factors in choosing the more useful technology for recovering polyphenolic compounds [24]. Another challenge is to prevent climate change caused by the emission of heat from different industries [25]. Hence, there is a growing demand for novel extraction methods with less solvent consumption, shorter time, and higher extraction yield [7]. Recently, many sustainable technologies such as microwave [26], ultrasound [27], cold plasma [28], pulsed electric field [29], pressurized liquid [30], and ohmic technology [31] have been utilized in the pre-treatment and extraction process of polyphenols. ...
... In this respect, Ghareaghajlou et al. (2021) reported that anthocyanins isolated from red cabbage represent the color in a broad range of pH values compared to anthocyanins recovered from other natural sources. Furthermore, polyphenols are used as components of smart packaging [25]. For instance, anthocyanins, catechins, theaflavins, etc., have pH-sensitive properties, and when they are used in food packaging, they show different colors in different pH solutions. ...
Article
Full-text available
Even though food by-products have many negative financial and environmental impacts, they contain a considerable quantity of precious bioactive compounds such as polyphenols. The recovery of these compounds from food wastes could diminish their adverse effects in different aspects. For doing this, various nonthermal and conventional methods are used. Since conventional extraction methods may cause plenty of problems, due to their heat production and extreme need for energy and solvent, many novel technologies such as microwave, ultrasound, cold plasma, pulsed electric field, pressurized liquid, and ohmic heating technology have been regarded as alternatives assisting the extraction process. This paper highlights the competence of mild technologies in the recovery of polyphenols from food by-products, the effect of these technologies on polyphenol oxidase, and the application of the recovered polyphenols in the food industry.
... In another segment of the food industry, phenolic compounds are used as components of smart/bioactive packaging [116][117][118]. For example, anthocyanins have been used as indicators of fish freshness [117] and as anti-lipidic peroxidation agents in olive oil packing [116]. ...
... For example, anthocyanins have been used as indicators of fish freshness [117] and as anti-lipidic peroxidation agents in olive oil packing [116]. Also, tannin-protein-based edible films have shown antioxidant activity and antimicrobial activity against Escherichia coli and Listeria innocua [118]. ...
Article
Full-text available
Experimental studies have provided convincing evidence that food bioactive compounds (FBCs) have a positive biological impact on human health, exerting protective effects against non-communicable diseases (NCD) including cancer and cardiovascular (CVDs), metabolic, and neurodegenerative disorders (NDDs). These benefits have been associated with the presence of secondary metabolites, namely polyphenols, glucosinolates, carotenoids, terpenoids, alkaloids, saponins, vitamins, and fibres, among others, derived from their antioxidant, antiatherogenic, anti-inflammatory, antimicrobial, antithrombotic, cardioprotective, and vasodilator properties. Polyphenols as one of the most abundant classes of bioactive compounds present in plant-based foods emerge as a promising approach for the development of efficacious preventive agents against NCDs with reduced side effects. The aim of this review is to present comprehensive and deep insights into the potential of polyphenols, from their chemical structure classification and biosynthesis to preventive effects on NCDs, namely cancer, CVDs, and NDDS. The challenge of polyphenols bioavailability and bioaccessibility will be explored in addition to useful industrial and environmental applications. Advanced and emerging extraction techniques will be highlighted and the high-resolution analytical techniques used for FBCs characterization, identification, and quantification will be considered.
... In this context, phenolic compounds produced from plant extracts, especially tannins, are being studied as prospective components for incorporation into polymer matrices to make food packaging bioactive films (Cano et al. 2020). Tannin is a major polyphenolic secondary metabolite widely distributed in the forestry sector and is found mainly in bark, stems, seeds, roots, buds, and leaves (Giovando et al. 2019;Tomak and Gonultas 2018). ...
Article
Full-text available
Tannin is a major polyphenolic secondary metabolite widely distributed in the forestry sector and can be added to polymer matrices to manufacture bioactive films for food packaging. Tannins have functional properties as antioxidants, antibacterial, and anti-inflammatories. Tannins are classified into two types, namely condensed tannins and hydrolyzable tannins. Tannins have been used primarily in food, wood, leather, pharmaceutical, and other industries. In the food industry, tannins are used to develop food packaging, preservation, and the function of the food industry. Tannin molecules have the advantage of combining with polymers or polymer surfaces, for example, synthetic polymers, biopolymers, and micro- and nano-sized fibers, which will form new products whose physical and chemical properties increase in functional properties because of the presence of hydrophilic and nucleophilic groups. Combining tannins with a polymer can be done by one-step reactive extrusion, layer by layer, dynamic vulcanization, acetylation, and in situ extraction methods. This paper describes general information about tannins, followed by applications using tannins, tannin-based hybrid materials, and methods of combining tannins with a polymer for food packaging purposes. Keywords: active packaging, bioactive film, polymer, secondary metabolite, tannins
... However, they are present in a huge variety of vegetables (Table 8.2). Tannins also have important applications in packaging, since they allow the production of protein-based biofilms with antimicrobial activity against Escherichia coli and Listeria innocua (Cano et al., 2020). Besides, they are historical ingredients in the textile sector since they can be used as natural dyes or mordants. ...
... But the additive eventually migrates out of the films. Tannins are occasionally added to improve some properties of casein (increase in antioxidant and antimicrobial activities and decrease in water solubility, vapor permeability, and stretchability) (Cano et al., 2020). ...
Article
Full-text available
Biobased natural polymers, including polymers of natural origin such as casein, are growing rapidly in the light of the environmental pollution caused by many mass‐produced commercial synthetic polymers. Although casein has interesting intrinsic properties, especially for the food industry, numerous chemical reactions have been carried out to broaden the range of its properties, most of them preserving casein's nontoxicity and biodegradability. New conjugates and graft copolymers have been developed especially by Maillard reaction of the amine functions of the casein backbone with the aldehyde functions of sugars, polysaccharides, or other molecules. Carried out with dialdehydes, these reactions lead to the cross‐linking of casein giving three‐dimensional polymers. Acylation and polymerization of various monomers initiated by amine functions are also described. Other reactions, far less numerous, involve alcohol and carboxylic acid functions in casein. This review provides an overview of casein‐based conjugates and graft copolymers, their properties, and potential applications.
... The quantification of TPC was performed according to the methodology described by Cano [31] with some modifications. Ten microliters of the sample were added to a semi-micro cuvette of a spectrophotometer, followed by 750 µL of distilled water. ...
Article
Full-text available
Grape seeds are an excellent source of flavonoids and tannins with powerful antioxidant properties. However, the astringency of tannins limits their direct incorporation into food. To overcome this challenge, we investigated the encapsulation of grape seed tannins within nanoliposomes formed by ultrasound cycling. We characterized the nanoliposomes’ physicochemical properties, including encapsulation efficiency, antioxidant activity, stability, microstructure, and rheological properties. Our findings reveal that the nanoliposomes exhibited excellent stability under refrigerated conditions for up to 90 days with a mean particle size of 228 ± 26 nm, a polydispersity index of 0.598 ± 0.087, and a zeta potential of −41.6 ± 1.30 mV, maintaining a spherical multilamellar microstructure. Moreover, they displayed high antioxidant activity, with encapsulation efficiencies of 79% for epicatechin and 90% for catechin. This innovative approach demonstrates the potential of using ultrasound-assisted nanoliposome encapsulation to directly incorporate grape seed tannins into food matrices, providing a sustainable and efficient method for enhancing their bioavailability and functionality.
... Byaruhanga et al. [64] thermally cross-linked the wet kafirin by microwave-heating and found that the maximum tensile strength of the resulting film increases by 39%, the elongation at break decreases by 37%, and the film becomes firmer with reduced plasticity. In recent years, tannin as a natural cross-linking agent has been widely studied in improving the mechanical properties of prolamin-based films [65][66][67][68]. Tannin is a secondary metabolite of plants and has strong complexation with proteins. ...
Article
Full-text available
Foods are susceptible to deterioration and sour due to external environmental influences during production and storage. Coating can form a layer of physical barrier on the surface of foods to achieve the purpose of food preservation. Because of its good barrier properties and biocompatibility, prolamin-based film has been valued as a new green and environment-friendly material in the application of food preservation. Single prolamin-based film has weaknesses of poor toughness and stability, and it is necessary to select appropriate modification methods to improve the performance of film according to the application requirements. The practical application effect of film is not only affected by the raw materials and the properties of the film itself, but also affected by the selection of preparation methods and processing techniques of film-forming liquid. In this review, the properties and selection of prolamins, the forming mechanisms and processes of prolamin-based coatings, the coating techniques, and the modifications of prolamin-based coatings were systematically introduced from the perspective of food coating applications. Moreover, the defects and deficiencies in the research and development of prolamin-based coatings were also reviewed in order to provide a reference for the follow-up research on the application of prolamin-based coatings in food preservation.
... Plants produce secondary metabolites including saponins, flavonoids, and tannins that are thought to be toxic to microbes. Tannins have antibacterial potential due to their basic character, which may allow VASAIT 1435 them to react with enzymes and proteins which leads in the disruption of cell membrane, thereby being considered as bactericidal by cessation of some metabolic activities (Cano et al., 2020). Acetone extract exhibited less antibacterial activity as compared to ethanol extract. ...
... In recent times, to meet the consumer various demands toward extending food shelf life and health concern of packaging materials in the food industry, the function of films has increased beyond the basic protection of foods, the development of active packaging by adding antioxidants and antibacterial agents is being focused (Bhargava, Sharanagat, Mor, & Kumar, 2020). Tannic acid (TA) as a natural origin bioactive substance is of particular interest in enhancing function properties of food packaging due to its antimicrobial and antioxidant capacity (Cano, Andres, Chiralt, & Gonzalez-Martinez, 2020) through many phenolic hydroxyl groups is easy to form intermolecular interactions with the functional groups of biopolymers, so it can work as a crosslinking agent improving the microstructure and enhance the mechanical properties, barrier properties, and antioxidant properties of the complex films. Furthermore, several studies reported that TA-Fe III nanocomposites (TF) constructed from the coordination interaction of Fe III ions and TA exhibited excellent photothermal properties and antibacterial ability, they are excellent candidates of good biocompatibility for food antibacterial packaging. ...
Article
As the demand for food quality and safety continues to rise, antimicrobial active packaging materials with good mechanical and barrier properties have received urgent attention from the food industry. In this study, three types of Ag/tannic acid-Fe III ion nanocomposites (TFA) were synthesized using an in-situ method and incorporated into a chitosan/gelatin/polyvinyl alcohol complex film (CF) to produce multifunctional and highly cross-linked active films. The impact of TFA prepared through three different methods on the microstructure and functional properties of the CF were investigated. The structure of the TFA-loaded films was investigated to confirm the strong intermolecular interactions between the polymers and TFA. The TFA established multidi-mensional physical interactions and cross-linked the polymers, thereby enhancing the mechanical properties of the CF and providing excellent antioxidant activity and photothermal effects. Under 808 nm near-infrared laser irradiation, the TFA-loaded films displayed potent antibacterial performance against both S. aureus and E. coli bacteria. This study demonstrated that the nanocomposite prepared via ascorbic acid reduction (TFAV) given the highest comprehensive performance rating to the film. It can be utilized not only for conventional food packaging but also as a continuous sterilization strategy for meat products storage due to its photothermal anti-bacterial functionality.
... However, this ranking may vary depending on the dielectric constant and chemical structure of the organic solvent (Cheok et al., 2012), as well as the specific chemical properties of the plant phytochemicals being extracted. Aqueous solutions have also been proposed as optimal extraction solvents for tannins due to the pronounced tendency of water-soluble tannin-protein complexes to form (Cano et al., 2020). ...
Article
Full-text available
Seaweeds, serving as valuable natural sources of phenolic compounds (PCs), offer various health benefits like antioxidant, anti‐inflammatory properties, and potential anticancer effects. The efficient extraction of PCs from seaweed is essential to harness their further applications. This study compares the effectiveness of different solvents (ethanol, methanol, water, acetone, and ethyl acetate) for extracting PCs from four seaweed species: Ascophyllum sp., Fucus sp., Ecklonia sp., and Sargassum sp. Among them, the ethanol extract of Sargassum sp. had the highest content of total phenolics (25.33 ± 1.45 mg GAE/g) and demonstrated potent scavenging activity against the 2,2‐diphenyl‐1‐picrylhydrazyl radical (33.65 ± 0.03 mg TE/g) and phosphomolybdate reduction (52.98 ± 0.47 mg TE/g). Ecklonia sp. had the highest content of total flavonoids (0.40 ± 0.02 mg QE/g) in its methanol extract, whereas its ethyl acetate extract contained the highest content of total condensed tannins (8.09 ± 0.12 mg CE/g). Fucus sp. demonstrated relatively strong antioxidant activity, with methanolic extracts exhibiting a scavenging ability against 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical (54.41 ± 0.24 mg TE/g) and water extracts showing ferric‐reducing antioxidant power of 36.24 ± 0.06 mg TE/g. Likewise, liquid chromatography–mass spectrometry identified 61 individual PCs, including 17 phenolic acids, 32 flavonoids, and 12 other polyphenols. Ecklonia sp., particularly in the ethanol extract, exhibited the most diverse composition. These findings underscore the importance of selecting appropriate solvents based on the specific seaweed species and desired compounds, further providing valuable guidance in the pharmaceutical, nutraceutical, and cosmetic industries. Practical Application The PCs, which are secondary metabolites present in terrestrial plants and marine organisms, have garnered considerable attention due to their potential health advantages and diverse biological effects. Using various organic/inorganic solvents during the extraction process makes it possible to selectively isolate different types of PCs from seaweed species. The distinct polarity and solubility properties of each solvent enable the extraction of specific compounds, facilitating a comprehensive assessment of the phenolic composition found in the seaweed samples and guiding industrial production.
... For the quantification of total phenols, expressed as gallic acid [µg/mL], the methodology described by Cano et al. (2020) was used with some modifications [41]. Briefly, 1 mL of 1 mg/mL TS or TLS (redispersed after centrifugation) was added to a 15 mL conical tube. ...
Article
Full-text available
The central nervous system (CNS) is particularly vulnerable to oxidative stress and inflammation, which affect neuronal function and survival. Nowadays, there is great interest in the development of antioxidant and anti-inflammatory compounds extracted from natural products, as potential strategies to reduce the oxidative/inflammatory environment within the CNS and then preserve neuronal integrity and brain function. However, an important limitation of natural antioxidant formulations (mainly polyphenols) is their reduced in vivo bioavailability. The biological compatible delivery system containing polyphenols may serve as a novel compound for these antioxidant formulations. Accordingly, in the present study, we used liposomes as carriers for grape tannins, and we tested their ability to prevent neuronal oxidative stress and inflammation. Cultured catecholaminergic neurons (CAD) were used to establish the potential of lipid-encapsulated grape tannins (TLS) to prevent neuronal oxidative stress and inflammation following an oxidative insult. TLS rescued cell survival after H2O2 treatment (59.4 ± 8.8% vs. 90.4 ± 5.6% H2O2 vs. TLS+ H2O2; p < 0.05) and reduced intracellular ROS levels by ~38% (p < 0.05), despite displaying negligible antioxidant activity in solution. Additionally, TLS treatment dramatically reduced proinflammatory cytokines’ mRNA expression after H2O2 treatment (TNF-α: 400.3 ± 1.7 vs. 7.9 ± 1.9-fold; IL-1β: 423.4 ± 1.3 vs. 12.7 ± 2.6-fold; p < 0.05; H2O2 vs. TLS+ H2O2, respectively), without affecting pro/antioxidant biomarker expression, suggesting that liposomes efficiently delivered tannins inside neurons and promoted cell survival. In conclusion, we propose that lipid-encapsulated grape tannins could be an efficient tool to promote antioxidant/inflammatory cell defense.
... It has a molecular weight of about 500 to 3000 Da [96] and is found in all parts of the plant, including bark, wood, leaves, fruit, and roots. One of their molecular activities is combining with proteins through non-specific forces such as hydrogen bonding and hydrophobic effects [97]. ...
Article
Biofilms are communities of microorganisms that can be harmful and/or beneficial, depending on location and cell content. Since in most cases (such as the formation of biofilms in laboratory/medicinal equipment, water pipes, high humidity-placed structures, and the food packaging machinery) these bacterial and fungal communities are troublesome, researchers in various fields are trying to find a promising strategy to destroy or slow down their formation. In general, anti-biofilm strategies are divided into the plant-based and non-plant categories, with the latter including nanoparticles, bacteriophages, enzymes, surfactants, active peptides and free fatty acids. In most cases, using a single strategy will not be sufficient to eliminate biofilm, and consequently, two or more strategies will inevitably be used to deal with this unwanted phenomenon. According to the analysis of potential biofilm inhibition strategies, the best option for the food industry would be the use of hydrolase enzymes and peptides extracted from natural sources. This article represents a systematic review of the previous efforts made in these directions.
... As seen in Figure 3 and Table 3, after the addition of loads in both the blend and composite methodologies, DPPH rates increased, displaying a slightly higher capacity to eliminate radicals than the control films. Such difference can be attributed to the high compatibility of the additives in the protein matrix, favoring the antioxidant activity of the medium (Zadeh et al., 2018;Cano et al., 2020;Mohanan et al., 2018). The loads of biomolecules added to the SPI samples (films A and B), are groups of phenolic compounds soluble in water that present antioxidant activity. ...
Article
Full-text available
In the present study, soy protein isolate (SPI) multifunctional bioplastics were prepared by casting, with the addition of tannins extracted from Stryphnodendron adstringens and kraft lignin. The films were obtained through biopolymer composites and blends method, prepared at three pHs (8.5, 9.5 and 10.5) and characterized by thermochemical studies, Fourier-transform infrared spectroscopy, scanning electron microscopy, water vapor permeability (WVP), antioxidant activity, water contact angle, surface energy, wettability, and mechanical tests. The composites presented better results when compared to the blend and control films, respectively, in the polarity, hydrophobicity, WVP and especially in the antioxidant activity tests. Nevertheless, no significant difference between the samples was noticed in the thermochemical and spectroscopic studies. The results presented the potential of the composites to produce SPI biopolymers with tannins and kraft lignin, leading to the development of multifunctional materials as an alternative for sustainable packaging.
... studied. It was revealed that the highest inhibition was noticed on surfaces of sliced meat in thyme essential oils incorporated with wheyprotein films. Furthermore, for the whey-protein films containing significant doses of essential oils, there was a considerable drop in the total viable bacterial population during storage. (Badr et al,. 2014). (Cano et al,. 2020) I n r e v i e w ...
... The addition of natural extract and/or nanomaterials into single film can inhibit Gram-positive bacteria in the range of 0.8-27.49 mm and 1.4-17.5 mm for Gram-negative bacteria (Cano et al., 2020;Lee et al., 2020). Meanwhile, the blended films with those mentioned additives reported an excellent inhibitory effect for Gram-positive bacteria in range 10.18-99.59 ...
Article
This review aims to provide a clear description of the compatibility between the main biopolymer matrix and the reinforcing components in manufacturing active and intelligent packaging film. The incorporation of natural extracts and/or nanomaterial improved the mechanical and barrier performance by increasing the cohesiveness of the biopolymer matrix. Meanwhile, the colour changes were due to the alteration of pH attributed to the pH-sensitivity of the bioactive compounds. This showed the great potential of the additives as a sensor for monitoring the real-time freshness of food products. High inhibitory effect for both Gram-positive and Gram-negative bacteria as well as the escalation of scavenging ability also presented a positive effect on antimicrobial and antioxidant properties of the packaging film. Hence, natural extract and/or nanomaterial showed promising additives in corresponding to the positive influences on sensing ability as well as the functional properties of the active and intelligent packaging film.
... [104] Different usage in food industries as bioactive packaging agents, for example, anthocyanin (fish freshness indicators) anti-lipidic peroxidation agents (olive oil packing), [105] and tannin edible films (proteinbased) have an antioxidative and antimicrobial effect on Listeria innocua and Escherichia coli. [106] Tannin water treatment is an active example of phenolic therapy, which functioned as an absorbent that can complex with protein and metal ions to eliminate the water pollutants (surfactants, heavy metals, pharmaceutical compounds, and dyes). Considering the sudden changes in consumers' demand for natural and healthy products over synthetic additives, polyphenol compounds have become more recognized in food industries. ...
Article
Full-text available
Consumers demand for functional foods and nutraceutical is increasing owing to their health endorsing properties. Natural bioactive compounds are getting attention due to their health promoting potential. In addition, the extraction of these bioactive compounds is a significant industrial and technological perspectives. These bioactive moieties can be extracted via various conventional and modern methods. For instance; solid-phase extraction, solid-phase micro-extraction, and liquid-liquid extraction are considered as traditional/conventional methods. In contrast, modern eco-innovative methods for extraction such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pulsed electric field (PEF), supercritical fluid extraction (SFE), instant controlled pressure drop (DIC), etc. are more economical and environment friendly. Additionally, these are ever-increasing demands of energy-efficient methods for the recovery of valuable compounds. Moreover, these methods produced less wastewater and hazardous substances. Conclusively, this review highlighted the conventional and modern extraction technologies and the role of these eco-innovative technologies in achieving the goal of a sustainable food system.
... The red arrow in Fig. 7 presents the diameter of the inhibition zone against (a) Staphylococcus aureus (SA) and (b) Escherichia coli (EC). This result confirms that gambir's bioactive compounds (such as flavonoids, tannin, and saponins), which can damage the plasma cell membrane leading to loss of intracellular components and consequent death of bacteria, remain effective when embedded in a BC film [25,60,61]. ...
Article
This work characterized bacterial cellulose (BC)/Uncaria gambir (G) biocomposite film prepared with ultrasonication treatment. Films were prepared from BC powder suspensions in distilled water without and with various loadings (0.05 g, 0.1 g, 0.2 g, 2 g) of G powder then treated using an ultrasonic probe at 1000 W for one hour. The results revealed that the ultrasonication treatment of the suspension greatly increased tensile strength (TS), elongation at break (EB), and toughness (TN) of a BC film by 3097%, 644%, and 32,600%, respectively, compared to non-sonicated BC film. After adding 0.05 g G into the sonicated BC powder suspension, TS, EB, and TN of the biocomposite film were improved to 105.6 MPa, 14.3%, and 8.7 MJ/m³, respectively. The addition of the G increased in antimicrobial activity of the film. This study indicates that biocomposite film is potentially useful for nanopaper production with good antimicrobial and high tensile properties.
... Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Shigella dysenteriae) [95]. Tannins inhibit extracellular enzymes, influence on microbial metabolism, and permeate the cytoplasmic membrane as antimicrobial mechanisms against microorganisms [96]. Nevertheless, they have some harmful effects, for example, reduce the digestibility of the nutrient, and possess antinutritional, mutagenic, and carcinogenic activities [94]. ...
... Caffeic and gallic acids can be used in chitosan-based biofilms to inhibit the growth of Bacillus subtilis and Staphylococcus aureus and enhance the film's oxygen and vapor permeability [260]. ...
Article
Full-text available
The modern linear agricultural production system allows the production of large quantities of food for an ever-growing population. However, it leads to large quantities of agricultural waste either being disposed of or treated for the purpose of reintroduction into the production chain with a new use. Various approaches in food waste management were explored to achieve social benefits and applications. The extraction of natural bioactive molecules (such as fibers and antioxidants) through innovative technologies represents a means of obtaining value-added products and an excellent measure to reduce the environmental impact. Cosmetic, pharmaceutical, and nutraceutical industries can use natural bioactive molecules as supplements and the food industry as feed and food additives. The bioactivities of phytochemicals contained in biowaste, their potential economic impact, and analytical procedures that allow their recovery are summarized in this study. Our results showed that although the recovery of bioactive molecules represents a sustainable means of achieving both waste reduction and resource utilization, further research is needed to optimize the valuable process for industrial-scale recovery.
... The combination of polyethyleneimine and metal ions with soy protein isolate improved the mechanical and antibacterial properties of packaging material (Li, Ye, et al., 2019). Protein (caseinate and gelatin) based films were incorporated with tannins to get active packaging material having antioxidant and antibacterial properties against E. coli and L. innocua (Cano, Andres, Chiralt, & González-Martinez, 2020). Nano multilayer coating methods are effectively used for shelf-life extension of fresh fruits and vegetables using layer by layer deposition of biopolymers (Arnon-Rips & Poverenov, 2018). ...
Article
Full-text available
The development of biopolymer-based functional colloids has potential application in the food sector for the fabrication of food products to fit in the current and future trends in this field. Protein is one of the most abundant biopolymers which can be used to synthesize innovative food ingredients due to their functional properties. Various functional colloids such as micro and nano complexes, molecular conjugates, edible films, hydrogels, oleogels, Pickering emulsions, etc. Can be prepared by proteins and their interactions with other biopolymers. Functional colloids have several applications such as stabilization of food, targeted delivery of bioactive compounds, preservation of food by edible coating and replacement of trans fatty acids as well as controlled solubilization of lipid in gastrointestinal fluids. In this review paper, recent studies on the different types of protein-based functional colloids and their applications in the food sector have been discussed.
... However, the use of biopolymers for the development of biobased packaging materials on industrial level is limited due to their weak mechanical strength and barrier properties compared to plastic materials (Tang et al., 2012). For this reason, natural polymers were frequently blended with other synthetic polymers or chemically modified with the purpose of enabling their applications in food packaging (Zubair and Ullah, 2019;Cano et al., 2020). ...
Article
Full-text available
Plastics materials used for food packaging are recalcitrant, leading to a growing global environmental problem, which arouses the attention of environmental protection departments in many countries. Therefore, to meet the increasing demand for sustainable and environment‐friendly consumer products, it is necessary for the food industry to develop natural antibacterial materials for food preservation. This review summarizes the common biodegradable natural antimicrobial agents and their applications in food preservation; as well as an overview of five commonly used biodegradable protein‐based polymers, such as zein, soy protein isolate, gelatin and whey protein, with special emphasis on the advantages of protein‐based biopolymers and their applications in food packaging industry.
... Gelatin is one of the most studied biopolymers for active edible packaging. As summarized in Table 3 different studies have evaluated the effect of incorporating essential oils [102][103][104][105][106], probiotic microorganisms [10,107,108], particles reinforcements [109][110][111][112][113][114][115][116][117], or used as a blend with other biopolymers [96,[118][119][120][121][122][123] into gelatin films. The addition of rice flour increased the WVP of films while the solubility decreased. ...
Article
Full-text available
Biodegradable polymers are non-toxic, environmentally friendly biopolymers with considerable mechanical and barrier properties that can be degraded in industrial or home composting conditions. These biopolymers can be generated from sustainable natural sources or from the agricultural and animal processing co-products and wastes. Animals processing co-products are low value, underutilized, non-meat components that are generally generated from meat processing or slaughterhouse such as hide, blood, some offal etc. These are often converted into low-value products such as animal feed or in some cases disposed of as waste. Collagen, gelatin, keratin, myofibrillar proteins, and chitosan are the major value-added biopolymers obtained from the processing of animal’s products. While these have many applications in food and pharmaceutical industries, a significant amount is underutilized and therefore hold potential for use in the generation of bioplastics. This review summarizes the research progress on the utilization of meat processing co-products to fabricate biodegradable polymers with the main focus on food industry applications. In addition, the factors affecting the application of biodegradable polymers in the packaging sector, their current industrial status, and regulations are also discussed.
... Collagen degradation was more efficient when Hamamelis virginiana tincture was used for 24 and 48 h, and it is a considerable indication, since the healing action of tannins that are present in the leaves of Hamamelis virginiana, is based on the precipitation of proteins on the epithelial surface, thereby forming a film, and this protection helps in healing through decreasing the permeability and exudation of the wound 27 . ...
Article
Full-text available
Objective: In this study, we aimed to determine the action of the tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris on tissues. For this, we investigated the histological sections of fixed skin tissue of Wistar rats for the changes in collagen and elastic fibers, epithelial cells, conjunctive cells, epidermal attachments, pigments, and granules using the optical microscopy technique. Since in the literature and published articles, the use of in vivo models, such as Wistar rats, is predominant to evaluate the healing action of herbal medicines. Methods: The tinctures of Hamamelis virginiana, Maytenus ilicifolia, and Casearia sylvestris, and ethanol 70% (blank) were used. The tinctures were obtained at 10% (w/v) through percolation using 70% ethanol (v/v) as the extraction liquid. This study was conducted in duplicate for each tincture and different incubation times (4, 24, and 48 h) at 37 °C in an oven. The slides used in this study (Wistar rat skin) were previously processed at the histology laboratory since the waste material was donated to conduct this experiment. The Research Ethics Committee approved the use of animals of the Life Sciences Center of the Pontifical Catholic University of Campinas (PUC-CAMPINAS) under the protocol approval number 367/08. Before initiating the staining process, the slides were removed from the oven, and the tincture deposited on the slides was removed. Weigert staining was performed subsequently. For semi-quantitative analysis, the histological sections were carefully observed, and the number of collagen and elastic fibers was evaluated based on the following scale: (+) normal fiber presence, (−) slight decrease, (− −) moderate decrease, and (− − −) intense decrease. The images were digitally captured to obtain the results using a photomicroscope. Results: The degradation of collagen fibers was best evidenced upon using Hamamelis virginiana tincture, which is concordant with the existing reports in the literature on its healing action via the precipitation of dermal proteins. Maytenus ilicifolia and Casearia sylvestris tinctures exhibited low proteolytic capacity as they only caused degradation of elastic fibers that are more delicate and very different from collagen in their constitution. Therefore, the application of the latter two as healing agents (which acts through precipitating proteins) is limited. Conclusions: This experimental histological model using the optical microscopy technique exhibits the advantage of agility and high efficiency as a simple and powerful approach.
... Other compounds present in food matrices can also influence the phase behavior in protein-polysaccharide systems. For example, phenolic compounds widely found in plant extracts can interact with proteins and carbohydrates through hydrogen bonds, hydrophobic interactions and electrostatic forces [12,13]. ...
Article
Aqueous two-phase system (ATPS) is a technique used for the separation of biopolymers in two aqueous phases. Some combinations of biopolymers can form a water-in-water (W/W) emulsion due to steric exclusion and thermodynamic incompatibility between these biopolymers under some specific conditions. In this work, the formation of W/W emulsions composed of sodium caseinate (SCN) and locust bean gum (LBG) was evaluated, using NaCl or yerba mate extract as the driving force for the phase separation, which was described by phase's diagrams. Phase diagrams are like fingerprints of ATPS systems, which demonstrate the specific conditions to develop separate phases. Phase diagrams of the two systems show that at the same concentrations of protein and carbohydrate, the addition of NaCl or extract induced the separation of the compounds differently. Salt promotes phase separation by steric exclusion, each phase being rich in one of the polymers. Since extract may also induce other effects, such as the formation of a SCN-extract-LBG complex, migration of LBG to the SCN-rich phase was promoted, modifying the characteristics of the tie lines in the phase diagrams. However, it was feasible to separate the protein in systems containing concentrated phenolic extract, whose incorporation is relevant considering its antioxidant activity.
... Furthermore, tannins from different sources (white peel grape, red peel grape, from oak bark, guava leaves etc.) have also proved to have antimicrobial activity. The addition of tannin make the package less soluble [76]. ...
Article
Full-text available
Food packaging is an area of interest not just for food producers or food marketing, but also for consumers who are more and more aware about the fact that food packaging has a great impact on food product quality and on the environment. The most used materials for the packaging of food are plastic, glass, metal, and paper. Still, over time edible films have become widely used for a variety of different products and different food categories such as meat products, vegetables, or dairy products. For example, proteins are excellent materials used for obtaining edible or non-edible coatings and films. The scope of this review is to overview the literature on protein utilization in food packages and edible packages, their functionalization, antioxidant, antimicrobial and antifungal activities, and economic perspectives. Different vegetable (corn, soy, mung bean, pea, grass pea, wild and Pasankalla quinoa, bitter vetch) and animal (whey, casein, keratin, collagen, gelatin, surimi, egg white) protein sources are discussed. Mechanical properties, thickness, moisture content, water vapor permeability, sensorial properties, and suitability for the environment also have a significant impact on protein-based packages utilization.
... The tannins from oak bark, red peel grape and white peel grape was used with the proteins in order determine the antimicrobial activity. The inhibitory activity of Escherichia coli and Listeria innocua was found in this study when the proteins was incorporated with the plants extracts while no inhibitory was found in the pure protein (Cano et al., 2020). The tannin can also be obtained using crude rice straw by separation and purification method to obtain tannin . ...
Article
Full-text available
This work aims to investigate the antimicrobial properties of colorimetric film using different types of anthocyanins on different types of microorganisms such as Escherichia coli, Staphylococcus aureus, Bacillus cereus, Listeria innocua, Pseudomonas aeruginosa and other types of microorganisms. Most of colorimetric film with addition of anthocyanins exhibits the antimicrobial properties which could prolong the shelf life of food products. Moreover, the methods to extract anthocyanins using different kinds solvent such as ethanol, methanol, tetrahydrofuran and others solvent also been studied. Finally, the effect of colorimetric films such as colour changes to monitor the freshness on different kinds of food products also been reported.
... 37 Tannins interact with proteins through hydrogen bonding or noncovalent bonds; this property was explored to develop protein-based biofilms with tannins that have antioxidant and antimicrobial activity against Escherichia coli and Listeria innocua. 38 ...
Article
Phenolic compounds are natural bioactive molecules found mainly in plant tissues that have shown interesting bioactivities, such as antioxidant, antimicrobial, anti-inflammatory, and antiproliferative activities, among others, which has led to great interest in their use by several industries. However, despite the large number of scientific studies on this topic, some issues still need to be studied and solved, such as the understanding of the main actions of these compounds in organisms. Besides their large potential applicability in industry, phenolic compounds still face some issues making it necessary to develop strategies to improve bioavailability, sustainable technologies of extraction and refinement, and stability procedures to increase the range of applicability. This review focuses on the most recent advances in the applications of phenolic compounds in different technological and medicinal areas. In addition, techniques to improve their sustainable resourcing, stability and bioavailability will be presented and discussed.
Article
Full-text available
Food phenolic compounds (PCs) and proteins interact and react via non-covalent and covalent routes to form phenolic compound–protein (PCP) complexes and conjugates. In the last decade, increasing research has focused on protein modification based on these interactions in various food systems. This review provides the mechanism of PCP complexation and conjugation and relevant analytical techniques for detection and quantification purposes. Moreover, key functional properties of PCP complexes and conjugates, including solubility, emulsifying property, antioxidant activity, thermal stability, anti-microbial activity and digestibility, are discussed. The applications of the complexes and conjugates as novel encapsulants to stabilise bioactive but sensitive as novel food ingredients are also overviewed. It is worth noting that the correlation between PCP complexation and conjugation and these functional properties are not fully understood. There is still research paucity exploring the applications of PCP complexes and conjugates as promising encapsulants. Future research is required to advance the science in this area and facilitate application.
Article
Current trends show a greater demand for packaging that maintains food free of pathogens (bacteria, fungi, and virus species). The most encouraging strategies imply the addition of active reagents as antimicrobial and radical scavenger components. Wood extractive structures show high potential as antimicrobial and antioxidant agents, mainly due to their phenolic structure. Their addition leads to enhanced antioxidant activity and reduces microbial growth. Terpenoid and phenol compounds potentially reduce free radical formation, avoiding oxidative stress. Alkaloids, phenols, flavonoids, and triterpenoids act on gram-negative antimicrobial activity groups. This review describes the potential of wood-based extractives in food primary active packaging, the methods of obtaining and purification, and the advantages and limitations of their applications.
Article
Full-text available
Strawberry (Fragaria x ananassa Duch.) is a highly perishable fruit whose characteristics make it susceptible to developing microorganisms. Plant extracts have been studied as an alternative to pesticides to control spoilage microorganisms, responding to the expectation of the population seeking a healthier way of life. The fungus Botrytis cinerea is a facultative pathogen of vegetables, which can affect all stages of the development of several fruits, such as the strawberry, where it causes gray rot. Trichilia catigua (catuaba), Paullinia cupana (guarana), Stryphnodendron barbatiman (barbatimão), and Caesalpinia peltophoroides (sibipiruna) are planted in the Brazilian flora and have demonstrated pharmacological properties in their extracts. This work aimed to treat strawberries with a biodegradable film containing extracts of these species to evaluate strawberry conservation. There were notable distinctions in mass loss between the extract-treated and control samples. The pH, total acidity (TA), and soluble solids parameters exhibited consistently significant means across both sets of samples. Luminosity increased over the course of days in the color parameters, with the exception of strawberries coated with guarana. The red color showed greater intensity, except for those coated with barbatimão extract. Considering the results, it is possible to conclude that the coatings used can become an alternative to enhance the conservation of strawberries.
Article
In the current study, the bioactive compounds such as total phenols, flavonoids, hydrolyzable tannins, and gallic acid were extracted from the bark of Swietenia macrophylla using four different solvents such as ethanol, methanol, acetone, and water. Among them, acetone exhibited the highest contents of bioactive compounds. To optimize the extraction process, a statistical approach was adopted using the central composite design (CCD) of response surface methodology (RSM). The five parameters at five different levels were chosen in the design of the experiments. A total of 32 experimental runs given by the design were fitted into the second-order regression model equation. The analysis of the model shows the best fit of the experimental data with an R2 of 0.9971 and a model F-value of 191.73. The optimal conditions of acetone concentration (56 %), the volume of acetone (22 mL), agitation speed (173 rpm), extraction temperature (31 °C), and extraction time (28 h) were noted from desirability function and showed a 2.0-fold increase in the contents of bioactive compounds when compared to unoptimized conditions. Further, the antimicrobial activity of 5 % (w/v) extract was tested against two-gram positive strains Bacillus sp, and Staphylococcus aureus, and two-gram negative strains Escherichia coli, and S. marcescens. The extract exhibited the 21 mm and 18 mm clear zone of diameter with 5 mm standard disc against the gram-positive strains tested whereas no clear zone was found against gram-negative strains. Finally, the antioxidant property was electrochemically analyzed using cyclic voltammetry and Differential pulse voltammetry, which confirmed the presence of multiple antioxidants in the extract.
Article
Full-text available
Whey and casein proteins, in particular, have shown considerable promise in replacing fossil-based plastics in a variety of food applications, such as for O2 susceptible foods, thereby, rendering milk proteins certainly one of the most quality-assured biopolymers in the packaging discipline. Properties like excellent gas barrier properties, proficiency to develop self-supporting films, adequate availability, and superb biodegradability have aroused great attention toward whey and other milk proteins in recent years. High thermal stability, non-toxicity, the ability to form strong inter cross-links, and micelle formation, all these attributes make it a suitable material for outstanding biodegradability. The unique structural and functional properties of milk proteins make them a suitable candidate for tailoring novel active package techniques for satisfying the needs of the food and nutraceutical industries. Milk proteins, especially whey proteins, serve as excellent carriers of various ingredients which are incorporated in films/coatings to strengthen barrier properties and enhance functional properties viz. antioxidant and antimicrobial. In this review, the latest techniques pertaining to the conceptualization of active package models/ systems using milk proteins have been discussed. Physical and other functional properties of milk protein-based active packaging systems are also reviewed. This review provides an overview of recent applications of milk protein-sourced active edible packages in the food packaging business.
Chapter
Biopolymers are degradable materials obtained from renewable sources that have been studied as promissory alternatives to substitute partially or completely food packaging based on synthetic polymers. Several biopolymers such as carbohydrates, proteins, and lipids have been studied in the last years, aiming for food packaging applications. Before commercial application, it is necessary to understand the physicochemical properties of biopolymer-based materials such as gas barrier (H 2 O, O 2 , and CO 2 ), mechanical properties (elastic modulus, tensile strength, and elongation at break), thermal stability, and chemical properties related to the interaction with foods. Biopolymers are biodegradable materials and have low cost; however, films and coatings manufactured with these macromolecules have poor barrier and mechanical properties, limiting their food packaging applications. In the last years, several researchers have aimed to improve the physicochemical properties of biopolymer-based materials. In this sense, this chapter aimed to review the state of the art regarding the use of biopolymers as matrix to manufacture films and coatings with potential applications in the food sector.
Article
To develop strong and tough bio-based composite films as replacements for synthetic polymer films is challenging. Based on the strong adhesion of the comb-like structure of geckos’ feet or pressure-sensitive resins on substrates, a comb-like polymer-aminated dialdehyde starch (A-DAS) was designed and prepared from polyamide polyamine polymer and dialdehyde starch via a Schiff-based reaction, and then combined with soy protein isolate (SPI) to develop a protein-based film. The comb-like A-DAS exhibited strong adhesion with SPI molecules by forming multiple hydrogen bonds, which created a noncovalent network that improved both the strength and toughness of the resultant film. The results showed that after integrating A-DAS (SPI:A-DAS weight ratio of 2:1), the tensile strength of the film dramatically increased by 1072.2% to 25.09 MPa, which is markedly better than that of other reported protein-based films. The toughness of the SPI/A-DAS film increased to 16.74 MJ/m³. Notably, the modified film could block 100% of the ultraviolet transmittance (<400 nm) owing to the imine group in A-DAS. This strategy offers a simple and effective way to construct strong and tough composite materials with ultraviolet-barrier performance, indicating potential applications in tissue engineering, hydrogels, and coating modification.
Article
Full-text available
Food is one of the key elements for survival of human beings. Preservation and quality assurance of food is necessary to meet the food demand in current era. Food protection is important at every step including pre-harvest, post-harvest, transportation, storage room and market shelves to get the good quality with enhanced shelf life. This review covers food packaging at pre-harvest and post-harvest level, types of food packaging (including active, intelligent and smart food packaging) and how to improve the antioxidant and antimicrobial properties of food using active food packaging. Nanotechnology is one the advanced technologies serving in food preservation, detailed advancements in nanotechnology based food packaging have also been summarized in this review. Overall, this review covers recent advances in food packaging including pre-harvest, post-harvest, intelligent, smart, active, and multifunctional food packaging.
Article
Three tannin extracts from different sources (white peel grape (W), red peel grape (R) and oak bark (O)) have been used to obtain active films based on different polysaccharides: chitosan (CH), methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC). Tannin-rich films were obtained by casting as monolayers (by blending all the components) and as bilayers (one polysaccharide layer plus one tannin layer applied as a coating). Microstructural and physicochemical properties (water solubility, water vapour permeability, mechanical and optical properties), as well as the antioxidant and antimicrobial activities of the films, were analysed. Tannins, regardless of their origin, acted as crosslinking agents when incorporated into CH or MC films due to the establishment of specific associations, mainly hydrogen bonds and hydrophobic interactions. Thus, these tannin-rich films turned less water soluble, mechanically stiffer and less stretchable. In contrast, tannins provoke precipitation in the HPMC film-forming solutions and the application of tannins onto the HPMC film surface gave rise to a weakened network due to the local precipitation of HPMC-tannin complexes. The greatest antioxidant capacity was found in both mono and bilayer tannin-rich MC based films in different food simulants, in line with a tannin release from the polymer matrix. The MC bilayer films also exhibited a bacteriostatic activity against both E.Coli and L. innocua. So, MC films with tannins could represent a good alternative as active coatings or packaging material so as to prevent the occurrence of oxidative reactions in sensitive food products or to control bacterial growth.
Article
The recent awareness of food safety has increased the attractiveness of natural polymer packaging film. However, the weak physicochemical properties have greatly restricted their practical applications. Therefore, in this work, gelatin was crosslinked by dialdehyde glucomannan, and tannic acid was introduced to enhance the properties of the gelatin-based films. The heat treatment enhanced the covalent crosslinking between dialdehyde glucomannan and gelatin. The tannic acid introduction resulted in darkened color, and enhanced UV blocking property and thermal stability of the films. And the novel gelatin films showed smooth surface and cross-section, enhanced mechanical properties, and reduced water vapor permeability. In addition, the enhanced crosslinking eliminated the increased swelling caused by tannic acid. More notably, the films contained a distinct antioxidant capacity and a significant inhibitory effect on S. aureus. This study demonstrated that tannic acid and the enhanced covalent crosslinking could synergistically improve the properties of the gelatin films for food packaging.
Article
Aim of this study was the development of an active packaging based on whey proteins (WP) functionalized with Pecan nut shell extract (PNSE). To this purpose, aqueous solutions of WP, PNSE and glycerol were mixed and characterized, whereas corresponding films were prepared by casting. Zeta-potential measurement revealed that the film forming solutions were stable, and the particle size was reduced further to the incorporation of PNSE, as a result of tannins-WP interactions. Films were handleable and homogeneous, and PNSE was able to improve their mechanical and barrier properties. PNSE-containing films inhibited the growth of the foodborne bacteria Enterococcus faecalis and Salmonella enterica subsp. enterica ser. Typhimurium. Ferric reducing/antioxidant power assay clearly highlighted the ability of PNSE to impart antioxidant properties to the films. Finally, simulated digestion experiments showed a significant lowering of the proteolysis rate in the presence of PNSE, although 40 % of the protein was still digested after 60 min incubation. Overall, these results put the basis for a possible use of PNSE functionalized WP-based films as new environmentally friendly candidates for increasing the shelf-life of foods.
Article
The development of high-performance and sustainable bio-adhesive materials has attracted significant research attention in recent years. However, producing high-performance biopolymer materials with desirable mechanical and antibacterial properties remains a challenge. Herein, a mussel-mimetic strategy is reported to fabricate a soy protein (SP)-based composite film via aqueous co-assembly of 3-aminophenylboronic acid-functionalized cellulose nanofibril ([email protected]) and hyperbranched polyester (HPE). The water-soluble HPE with numerous hydroxyl end groups was synthesized by using a facile and green method. Through enhanced dynamic covalent interactions and intermolecular sacrificial hydrogen bonds, the incorporated [email protected] hybrids with conjugated cis-diols strongly interact and entangle with biopolymer chains in the hyperbranched network. As a result of multiple synergistic cross-linking, the toughness and strength of the SP/HPE/[email protected] film increase by 574% and 346% to 10.05 MJ/m³ and 14.23 MPa, respectively. Additionally, the film offers excellent antibacterial activity, flame retardance, and thermal stability. This sustainable approach should open new avenues for the design and development of biomimetic plant-derived functional materials in biomass adhesive and active packaging.
Article
Full-text available
Functionalization of protein-based materials by incorporation of organic and inorganic compounds has emerged as an active research area due to their improved properties and diversified applications. The present review provides an overview of the functionalization of protein-based materials by incorporating TiO 2 nanoparticles. Their effects on technological (mechanical, thermal, adsorptive, gas-barrier, and water-related) and functional (antimicrobial, photodegradation, ultraviolet (UV)-protective, wound-healing, and biocompatibility) properties are also discussed. In general, protein-TiO 2 hybrid materials are biodegradable and exhibit improved tensile strength, elasticity, thermal stability, oxygen and water resistance in a TiO 2 concentration-dependent response. Nonetheless, they showed enhanced antimicrobial and UV-protective effects with good biocompatibility on different cell lines. The main applications of protein-TiO 2 are focused on the development of eco-friendly and active packaging materials, biomedical (tissue engineering, bone regeneration, biosensors, implantable human motion devices, and wound-healing membranes), food preservation (meat, fruits, and fish oil), pharmaceutical (empty capsule shell), environmental remediation (removal and degradation of diverse water pollutants), anti-corrosion, and textiles. According to the evidence, protein-TiO 2 hybrid composites exhibited potential applications; however, standardized protocols for their preparation are needed for industrial-scale implementation.
Article
Full-text available
In this work, active films based on starch and PVA (S:PVA ratio of 2:1) were developed by incorporating neem (NO) and oregano essential oils (OEO). First, a screening of the antifungal effectiveness of different natural extracts (echinacea, horsetail extract, liquid smoke and neem seed oil) against two fungus (P. expansum and A. niger) was carried out. The effect of NO and OEO incorporation on the films’ physical and antimicrobial properties was analyzed. Only composite films containing OEO exhibited antibacterial and antifungal activity. Antibacterial activity occurred at low OEO concentration (6.7%), while antifungal effect required higher doses of OEO in the films. Incorporation of oils did not notably affect the water sorption capacity and water vapor barrier properties of S-PVA films, but reduced their transparency and gloss, especially at the highest concentrations. The mechanical response of the S-PVA films was also negatively affected by oil incorporation but this was only relevant at the highest oil ratio (22%). S-PVA films with 6.7% of OEO exhibited the best physical properties, without significant differences with respect to the S-PVA matrix, while exhibiting antibacterial activity. Thus, the use of OEO as a natural antimicrobial incorporated into starch-PVA films represents a good and novel alternative in food packaging applications.
Article
Full-text available
Grape pomace is a potential source of natural antioxidant and antimicrobial agents. Phenolic compounds, antioxidant, and antibacterial properties of pomace extracts from four Virginia-grown grape varieties were investigated. White grape pomaces had higher (P < 0.05) solvent extraction yield than red varieties. Concentrations of total phenolic (TPC), total flavonoid (TFC), total anthocyanin (TAC), tannins, condensed tannins (CT), as well as antioxidant capacities (DPPH• and ABTS•+free radical scavenging) differed (P < 0.05) among four pomace extracts. ABTS•+ scavenging capacity was positively correlated with TPC, TFC, tannins, and CT (P < 0.05), whereas DPPH• capacity was positively correlated with TAC (P < 0.05). Nine flavonoid compounds were identified, of which catechin and epicatechin were the two most abundant. Antibacterial activity was observed against Listeria monocytogenes ATCC 7644 and Staphylococcus aureus ATCC 29213, but not against Escherichia coli O157:H7 ATCC 3510 and Salmonella typhimurium ATCC 14028. L. monocytogenes was more susceptible than S. aureus.
Article
Full-text available
Compounds of pharmacological interest (tannins) were isolated from the plant species, Solanum trilobatum Linn and assayed against the bacteria, Staphylococcus aureus, Streptococcus pyrogens, Salmonella typhi, Pseudomonas aeruginosa, Proteus vulgaris and Escherichia coli using agar diffusion method. Tannins exhibited antibacterial activities against all the tested microorganisms. S.aureus was the most resistant to tannins isolated from the plant material followed by Streptococcus pyrogens, Salmonella typhi, Escherichia coli, Proteus vulgari and Pseudomonas aeruginosa. Minimum inhibitory concentration of the tannins ranged between 1.0 and 2.0 mg/ml while the minimum bactericidal concentration ranged between 1.5 and 2.0 mg/ml.
Article
Full-text available
The binding of tannin fraction to protein fractions isolated from broad bean seeds was studied by precipitating potential and fluorescence quenching methods. The tannin fraction with high proanthocyanidins content was isolated from broad bean coats. Storage proteins of broad bean, 11S, 7S, and 2S, were isolated from broad bean cotyledons and purified. Gelatin, BSA, as well as broad bean 2S and 7S protein fractions exhibited similar shape of curves illustrating the effect of pH on protein precipitation and were precipitated by broad bean tannin fraction over the wide range of pH. For pea proteins isolate and 11S fraction of broad bean proteins, quite different effect of pH was observed. The relationships between the amount of protein–polyphenols complex precipitated and the content of tannin fraction were linear and characterized by high squared correlation coefficients ranging from 0.9613 to 0.9938. Among the protein fractions isolated from broad bean seeds, the highest precipitating potential was noted for 11S fraction, followed by 7S and 2S fractions and amounted to 1.63, 1.34, and 0.87, respectively. To characterize the association of proteins with phenolic compounds yielding formation of soluble complexes, fluorescence spectroscopy was applied. Similarly, the most extensive fluorescence quenching was observed in the case of 11S protein fraction. KeywordsBroad bean–Coat tannin fraction–Storage proteins–Phenolics–proteins interaction–Fluorescence quenching
Article
Full-text available
Antimicrobial films were prepared by incorporating different concentrations of tea tree essential oil (TTO) into chitosan (CH) films. Film-forming dispersions (FFD) were characterized in terms of rheological properties, particle size distribution and ζ-potential. In order to study the impact of the incorporation of TTO into the CH matrix, the water vapour permeability (WVP), mechanical and optical properties of the dry films were evaluated. The properties of the films were related with their microstructure, which was observed by SEM. Furthermore, the antimicrobial effectiveness of CH–TTO composite films against Listeria monocytogenes and Penicillium italicum was studied.
Article
Full-text available
The success of chemotherapy lies in the continuous search for new drugs to counter the challenge posed by resistant strains. Methanol extracts of six plant species traditionally used in Indian folklore medicine for the treatment of various bacterial and fungal infections were investigated for in vitro antimicrobial activity against pathogens namely Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger by disc diffusion method. Methanol extracts of Eugenia jambolana and Cassia auriculata showed the highest toxicity against all the bacteria. The plant extracts showed antibacterial activity but not antifungal activity against any of the fungi used. Minimum inhibitory concentration (MIC) assay were determined for these two extracts against bacteria. E. jambolana revealed the highest antimicrobial activity at a minimum oncentration (0.75 mg/ml) against S. aureus. The phytochemical analysis carried out revealed the presence of coumarins, flavanoids, glycosides, phenols, tannins, saponins and steroids. Alkaloids were not detected from any of the plant extracts under study. The resultsprovide justification for the use of the plants in folk medicine to treat various infectious diseases.
Article
Full-text available
Astringency is a sensation in the mouth used in judging the quality of red wine. The rough, dry, and puckering sensation called astringency is the result of an interaction between tannins and saliva proteins, mainly proline-rich proteins (PRP), which leads to the formation and precipitation of a complex. A dry and rough sensation is then perceived in the mouth. To get an insight into astringency at the molecular level we investigated: (i) An efficient and iterative method for 4-8 procyanidin synthesis, which gives rise to all possible 4-8 procyanidins up to the tetramer with total control of degree of oligomerization and stereochemistry. (ii) The 3D-structural preferences, which take into account their internal movements, using 2D NMR and molecular modeling. (iii) The self-association process in water or hydroalcoholic solutions using diffusion NMR spectroscopy that gives the active proportion of tannins able to fix proteins. (iv) A comprehensive description of the PRP-procyanidin complex formation to get information about stoichiometry, binding site localization, and affinity constants for different procyanidins. The data collected suggest that the interactions are controlled by both procyanidin conformational and colloidal state preferences. All these results provide new insights into the molecular interpretation of tannin astringency.
Article
Full-text available
El término tanino se acuñó históricamente por el uso empírico que se daba a algunos extractos vegetales para el proceso de tanaje o conversión de las pieles de animales en cuero desde hace más de cien años. El desarrollo de las modernas técnicas instrumentales para la elucidación estructural de sustancias orgánicas, permitió el inicio científico en el área de polifenoles vegetales, término sugerido por el doctor Edwin Haslam en lugar de taninos. En esta revisión se discuten algunos hechos históricos, definiciones, técnicas de aislamiento y elucidación estructural, clasificación y aplicaciones de estos compuestos, desde la curtiembre hasta la industria alimenticia.
Article
Full-text available
The antibacterial activities of 10 different plant polyphenols were evaluated by comparing their minimum inhibitory concentrations (MICs) against several food-borne pathogenic bacteria, Staphylococcus aureus (20 strains), some serotypes of the genus Salmonella (26 strains), Escherichia coli (23 strains), and some species of the genus Vibrio (27 strains). The polyphenols examined were epigallocatechin (1), epigallocatechin-3-O-gallate (2), punicalagin (3), tannic acid (4), castalagin (5), prodelphinidin (6), geraniin (7), procyanidins (8), a theaflavin mixture of black tea (9), and green tea polyphenols treated with loquat polyphenol oxidase (10). The average MICs of all polyphenols against S. aureus and the genus Vibrio (192+/-91 and 162+/-165 microg/ml, respectively) were much lower than the values against the genus Salmonella and E. coli (795+/-590 and 1519+/-949 microg/ml, respectively) (p<0.01). The coefficient of variation of the MICs of all polyphenols against S. aureus was the least and that against the genus Vibrio was the greatest. The mean MICs of each plant polyphenol against S. aureus (98-389 microg/ml) and the genus Vibrio (68-488 microg/ml) were similar. The relatively lower mean MIC values of 1, 2, 5, and 6 suggest the importance of 3,4,5-trihydroxyphenyl groups in antibacterial activity.
Article
Whey proteins were modified by reaction with selected phenolic compounds (ferulic‐, chlorogenic‐, caffeic‐ and gallic acid) and related substances (quinic acid and p‐quinone) as well as with extracts from coffee, tea, potato and pear at pH 9. The derivatives formed were characterized in terms of their physicochemical and digestion properties. The derivatization was accompanied by a reaction at the lysine and tryptophan side chains, whereby their content was decreased in comparison to that in the control whey proteins. Moreover, the solubility of the derivatives decreased over a broad pH range and the derivatization influenced the hydrophobe–hydrophile character of the whey proteins. The isoelectric points were shifted to lower pH values in the order of reactivity as follows: gallic acid > p‐quinone > caffeic acid > chlorogenic acid. The other derivatives showed no or few changes compared to the control whey proteins. The formation of high molecular fractions was documented with SDS‐PAGE. Especially the derivatives of chlorogenic‐, caffeic‐, gallic acid and p‐quinone showed an increase in molecular weight of β‐lactoglobulin fraction from 18 300 to 20 000 Da. A dimer formation in molecular range 40 000 was also registered. MALDI‐TOF‐MS was applied to characterize the binding of the individual phenolic compounds or their oxidation products to the whey protein fractions, α‐lactalbumin and β‐lactoglobulin. In vitro experiments showed that the digestion of the derivatized whey proteins with the enzymes of the gastrointestinal tract (trypsin, chymotrypsin, pepsin and pancreatin) was adversely effected. Similar results with regard to physicochemical characterization and digestion properties of the whey proteins treated with the applied extracts from plant beverages, fruit and vegetable were also documented. Coffee and tee were comparatively the most reactive extracts.
Article
The kinetic behaviour of polyphenols common in fruits as free radical scavengers was studied using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH•). After addi‐tion of different standard concentrations to DPPH· (0·025 g litre⁻¹), the percentage of remaining DPPH• was determined at different times from the absorbances at 515 nm. The percentage remaining DPPH• against reaction time followed a multiplicative model equation: ln [DPPHREM•]=b ln t+ln a. The slopes of these equations may be useful parameters to define the antioxidant capacity. The steeper the slope, the lower the amount of antioxidant necessary to decrease by 50% the initial DPPH• concentration (EC50). This parameter, EC50, is widely used to measure antioxidant power, but it does not takes into account the reaction time. Time needed to reach the steady state to the concentration corresponding at EC50 (TEC50) was calculated, and antiradical efficiency (AE) was proposed as a new parameter to characterise the antioxidant compounds where AE=1/EC50TEC50. It was shown that AE is more discriminatory than EC50. AE values are more useful because they also take into account the reaction time. The results have shown that the order of the AE (×10⁻³) in the compounds tested was: ascorbic acid (11·44)>caffeic acid (2·75)⩾gallic acid (2·62)>tannic acid (0·57)⩾DL‐α‐tocopherol (0·52)>rutin (0·21)⩾quercetin (0·19)>ferulic acid (0·12)⩾3‐tert‐butyl‐4‐hydroxyanisole, BHA (0·10)>resveratrol (0·05). © 1998 SCI.
Article
Depending on their structure, tannins are known to strongly complex proteins and alter their functionality. This study aimed to determine effect of polymeric condensed tannins from sorghum (proanthocyanidins, PA), versus tannic acid (hydrolysable tannins) on rheological properties and stability of wheat gluten films and foams; monomeric catechin was used for comparison. Gluten films were solution-cast and assessed for tensile strength, aqueous solubility, and stability to protease hydrolysis. Wheat flour batter and isolated gliadins, glutenins, and starch viscosity and stability at room temp and under cook-cool cycles were assessed. PA-treated film, but not tannic acid or catechin films, showed increased (p < 0.05) tensile strength (2.2X vs control), and decreased aqueous solubility and protease degradation at pH 2.0, suggesting PA extensively cross-linked gluten. Both PA and tannic acid dramatically improved batter stability vs control and catechin (8% vs 38% separation at 60 min), although PA was more effective over 4 h. Surprisingly, in a cook-cool cycle, PA, but not tannic acid, dramatically increased peak and final paste viscosity (53% and 35%, respectively, vs control). Using isolated flour components, this was found to be largely due to PA uniquely cross-linking denatured gliadin fraction during the heating cycle, likely through hydrophobic interactions with exposed hydrophobic amino acid residues. Our findings indicate that differences in tannin conformation lead to different gluten protein binding mechanisms, which can be uniquely used to expand gluten functionality. The sorghum derived polymeric PA interact more strongly with gluten proteins than tannic acid.
Article
The objective of this work is to optimize a new method of grape pomace application in food industries, based on the microwave-assisted extraction of phenolic compounds followed by their encapsulation by spray drying. Mixtures of maltodextrin and milk proteins were used as wall materials. An expected integrated mean-squared error (EIMSE) optimal design was applied to determine the effects of inlet air temperature, ratio of core to wall material, and drying air flow rate on encapsulation efficiency and yield. Characterization of powder properties was accomplished to determine if successful development of the product was achieved. Mathematical models were developed to describe the relationship between the operating and response variables. In this case of yield, the inclusion of a new independent variable, the outlet air temperature, improved the predictive ability of the model. Moreover, a good correlation was found between the product yield and the amount that the droplet temperature has exceeded its glass transition temperature. The optimum values of encapsulation efficiency (92.49%) and yield (37.28%) were predicted. Furthermore, the antioxidant capacity and stability of the crude and the encapsulated extract were evaluated during storage at accelerated conditions.
Article
Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression moulding, incorporating or not cinnamaldehyde in the PLA layer. Films were characterized as to their microstructure and barrier, tensile and optical properties, as well as thermal behaviour, X-Ray diffraction pattern and FTIR spectra. Bilayers using semicrystalline PLA, instead of starch, were also analysed for comparison purposes. Despite the lower ratio of cast PLA sheet in the bilayer assembly (about 1/3 of the film thickness), a great improvement in tensile and water vapour barrier properties was achieved with respect to the net starch films, the films maintaining high transparency and oxygen permeability as low as starch films. When cinnamaldehyde was included in the cast PLA sheet, films became thinner due to the losses of the volatile active during processing, but the improvement in barrier properties was maintained, with lower mechanical resistance. Thermal analyses revealed diffusion of cinnamaldehyde or low molecular weight compounds from cast PLA layer to the adhered sheets (starch or semicrystalline PLA) which contributed to plasticizing the amorphous regions and affected crystallization pattern of PLA, as also revealed by the X-Ray diffraction patterns. The obtained results offer an interesting option to obtain high barrier-highly resistant active films from thermoplastic starch and amorphous PLA, including cinnamaldehyde as active compound.
Article
The effects of gelatins used as fining agents on the amount and nature of polyphenols removed from wine were studied. A red wine was treated with differently hydrolysed gelatins. Polyphenols were analyzed by fractogel chromatography followed by reversed-phase HPLC preceded by thiolysis for condensed tannins. The phenolic composition and content of wine were not significantly affected by gelatin fining treatments. Nevertheless, the polyphenols precipitated were characteristic. Gelatins preferentially removed high molecular weight galloylated proanthocyanidols. Proanthocyanidin precipitation was quite similar for all the gelatins examined except for the largest molecular weight protein which precipitated lower amount of proanthocyanidins with an additional selectivity for epigallocatechin-rich tannins.
Article
The influence of the amylose:amylopectin ratio on the properties of pea, potato and cassava starch films and the effect of the incorporation of rice bran of two different particle sizes were studied. The structural, mechanical, optical and barrier properties of the films were analyzed after 1 and 5 weeks. The high content of amylose gave rise to stiffer, more resistant to fracture, but less stretchable films, with lower oxygen permeability and greater water binding capacity. Although no changes in the water vapour permeability values of the films were observed during storage, their oxygen permeability decreased. Throughout storage, films became stiffer, more resistant to break, but less stretchable. Rice bran with the smallest particles improved the elastic modulus of the films, especially in high amylose content films, but reduced the film stretchability and its barrier properties, due to the enhancement of the water binding capacity and the introduction of discontinuities.
Article
The effect of sodium caseinate addition on corn starch films was studied in terms of microstructural, mechanical, optical and water and oxygen barrier properties and the changes they underwent during their 5 weeks' storage under controlled conditions. The influence of the polymer mixture on the degree of crystallization of the films was also analysed. The following starch: protein ratios were considered. 100:0, 75:50, 50:50 and 0:100. SEM Microstructure analysis revealed the compatibility of both hydrocolloids since no phase separation was observed. The addition of sodium caseinate to the starch films provided films that were less stiff and resistant to fracture but more flexible and deformable than pure starch films, with similar water vapour permeability values. The films became more permeable to oxygen as their sodium caseinate content increased in line with the higher permeability values of the protein film. Incorporating sodium caseinate to starch films provoked a slight increase in transparency, but a loss of gloss, which also decreased in composite films during storage. The re-arrangement of polymer chains during storage caused a loss of mechanical resistance, stretchability and gloss in composite films.
Article
New trends in edible films focus on the improvement of their functionality through the incorporation of active compounds, such as antimicrobial or antioxidant agents. Resveratrol is a natural antioxidant found in a variety of plant species, such as grapes, and could be used for minimizing or preventing lipid oxidation in food products, retarding the formation of oxidation products, maintaining nutritional quality and prolonging the food shelf life. The aim of this work was to develop and characterize two different polymeric composite films (made with chitosan (CH) and methylcellulose (MC)) containing different amounts of resveratrol. This compound could be incorporated efficiently into both films, but provoke structural changes in the matrices, which became less stretchable (65–70% reduction of deformation at break at the greatest resveratrol content) and resistant to fracture (26 and 54% reduction of tensile at break for MC and CH, respectively, at the greatest resveratrol content) more opaque (significant reduction of the internal transmittance) and less glossy (about 60–65% reduction of gloss at the greatest resveratrol content). Film barrier properties were hardly improved by the presence of resveratrol; water vapour and oxygen permeability tend to slightly decrease when resveratrol was incorporated into both polymers. Composite films showed antioxidant activity, which was proportional to the resveratrol concentration in the film. None of the films showed antimicrobial activity against Penicillium italicum and Botrytis cinerea. Thus, these films could be applied to food products which are sensitive to oxidative processes to prolong their shelf life.
Article
Edible films, based on sodium caseinate containing three different concentrations of ferulic acid or α-tocopherol (20, 40 and 60mg/g sodium caseinate), were obtained in order to evaluate the effect of these compounds on properties of the caseinate matrices. Special emphasis was placed on their effect on the films’ oxygen barrier properties, which are decisive in the prevention of the oxidation of foods containing lipids. Films were characterized as to their tensile, optical and surface properties as well as their barrier properties to water vapor, oxygen and aroma compounds (n-hexanal and n-hexanol). Ferulic acid was more efficient at reducing oxygen and n-hexanal permeability than α-tocopherol. Although ferulic acid slightly increased the stiffness of films at low concentration, in general, both antioxidants slightly reduce mechanical resistance, water vapor permeability, gloss and transparency of the films.
Article
Walnut (Juglans regia L.) kernels have important amounts of phenolic compounds. The objectives of the work were twofold: (a) to extract the phenolic fraction from hulls and walnut flour, and to examine its antioxidant capacity and (b) to evaluate the effect of hull removal on solubility of protein fractions from walnut flour. In accordance with their higher total phenolic content, hull extracts had stronger antioxidant activity than had flour extracts. The presence of phenolic compounds decreased protein solubility in walnut flour obtained from whole kernels. Dehulling of kernels significantly improved protein recovery but this result was strongly affected by the solvent system employed. Proteins from whole kernels, especially those extracted with water and NaCl solution, had a reduced solubility, indicating that phenolics bind to proteins when they are dispersed in aqueous media at neutral pH. The results are discussed in the light of the different complex-forming mechanisms that bind phenolics to proteins.
Article
Nanospheres were produced by molecular assembly between tannin and gelatin because of the synergistic interaction of the hydrophobic effect and hydrogen bonding. The factors that influenced the production of nanospheres, such as sample concentration, mass ratio between tannin and gelatin, reaction temperature, pH, and reaction time, were studied. Moreover, the nanospheres were analyzed and characterized by a particle size analyzer, UV–vis spectrophotometer, and TEM. It was concluded that the critical point was important for the assembled nanospheres. The tannin/protein mass ratio should be lower than the critical point. The concentration of tannin should be confined to a relatively low level. The proper range of the reaction temperatures was usually between 10°C and 50°C. It was steady for nanospheres assembled when the pH value of the gelatin solution was within ±1 IEP of the gelatin. After the reaction had gone on for more than 48 h, the assembled nanospheres became stable. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3125–3130, 2006
Article
Edible active films based on sodium caseinate (SC) and calcium caseinate (CC) plasticized with glycerol (G) at three different concentrations and carvacrol (CRV) as active agent were prepared by solvent casting. Transparent films were obtained and their surfaces were analysed by optical microscopy and scanning electron microscopy (SEM). The influence of the addition of three different plasticizer concentrations was studied by determining tensile properties, while Fourier transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to evaluate the structural and thermal behavior of such films. The addition of glycerol resulted in a reduction in the elastic modulus and tensile strength, while some increase in the elongation at break was observed. In general terms, SC films showed flexibility higher than the corresponding CC counterparts. In addition, the presence of carvacrol caused further improvements in ductile properties suggesting the presence of stronger interactions between the protein matrix and glycerol, as it was also observed in thermal degradation studies. FTIR spectra of all films showed the characteristic bands and peaks corresponding to proteins as well as to primary and secondary alcohols. In summary, the best results regarding mechanical and structural properties for caseinates-based films containing carvacrol were found for the formulations with high glycerol concentrations.
Article
The kinetic behaviour of polyphenols common in fruits as free radical scavengers was studied using 2,2-diphenyl-1-picrylhydrazyl (DPPH•). After addi-tion of different standard concentrations to DPPH· (0·025 g litre−1), the percentage of remaining DPPH• was determined at different times from the absorbances at 515 nm. The percentage remaining DPPH• against reaction time followed a multiplicative model equation: ln [DPPHREM•]=b ln t+ln a. The slopes of these equations may be useful parameters to define the antioxidant capacity. The steeper the slope, the lower the amount of antioxidant necessary to decrease by 50% the initial DPPH• concentration (EC50). This parameter, EC50, is widely used to measure antioxidant power, but it does not takes into account the reaction time. Time needed to reach the steady state to the concentration corresponding at EC50 (TEC50) was calculated, and antiradical efficiency (AE) was proposed as a new parameter to characterise the antioxidant compounds where AE=1/EC50TEC50. It was shown that AE is more discriminatory than EC50. AE values are more useful because they also take into account the reaction time. The results have shown that the order of the AE (×10−3) in the compounds tested was: ascorbic acid (11·44)>caffeic acid (2·75)⩾gallic acid (2·62)>tannic acid (0·57)⩾DL-α-tocopherol (0·52)>rutin (0·21)⩾quercetin (0·19)>ferulic acid (0·12)⩾3-tert-butyl-4-hydroxyanisole, BHA (0·10)>resveratrol (0·05). © 1998 SCI.
Article
Green tea contains a high percentage of polyphenols, which are potent antioxidant and antimicrobial agents. However, interactions between polyphenols and food components may decrease their potential benefits. The aim of the study was to evaluate whether the antioxidant and antimicrobial capacities of different Argentinean green tea varieties could be affected by whey proteins. The results showed some degree of masking in the antioxidant and antimicrobial activity of green tea infusions when whey proteins are present. The degree of inhibition of antioxidant activity in each variety did not depend on the polyphenol concentration, indicating the importance of the particular polyphenol composition of each variety. The CH 410 variety exhibited the best performance as antioxidant and antimicrobial, even in the presence of whey proteins. The antimicrobial effects in the presence of whey proteins correlated with the polyphenol content of the green tea infusions and increased with the reduction of whey protein concentration. The antimicrobial effectiveness was similar within a pH range from 4.0 to 7.0, allowing its application to a wide group of foods.
Article
The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
Article
Antimicrobial films were prepared by incorporating different concentrations of sodium lactate (Na lactate), potassium sorbate (K sorbate) and nisin into sorbitol-plasticized sodium caseinate (SC) films. The impact of antimicrobial compounds on the water sorption, water vapor barrier properties and thermo-mechanical behavior of SC films was investigated. Furthermore, their antimicrobial effectiveness against Listeria monocytogenes was studied as a function of antimicrobial concentration. The water content and water vapor permeability (WVP) of SC films increased with increasing Na lactate and K sorbate concentration, with Na lactate-containing SC films showing higher capacity to absorb moisture and greater WVP values than the films containing K sorbate. On the other hand, nisin addition did not cause significant changes in the water uptake and WVP of SC films. The incorporation of Na lactate and K sorbate affected in different way the glass transition temperature (Tg defined as tan δ peak) of antimicrobial SC films, with Na lactate increasing and the K sorbate depressing the Tg of the system. The addition of increasing Na lactate and K sorbate concentration resulted in reduction of Young modulus (E) and maximum tensile strength (σmax) and increasing of elongation at break (% EB) suggesting that both antimicrobials acted as plasticizers for the SC films. Nisin-containing SC films were the most effective in reducing growth of L. monocytogenes, followed by K sorbate-impregnated SC films, whereas films containing Na lactate were slightly effective in this respect and only at the higher concentration (40% w/w film dry basis). The results indicated that for effective applications of antimicrobial coatings in foods, sufficient knowledge is required not only on the independent properties of the coating film and the antimicrobial compound but also on their interactions.
Article
Film-forming emulsions were formulated with sodium caseinate and two essential oils (cinnamon or ginger) and films were obtained by casting. At the low oil proportion being tested (maximum ratio protein:oil 1:0.100), the lipid did not affect the mechanical behaviour of the protein films. The water vapour permeability was slightly reduced by both oils. Cinnamon oil greatly affected the optical properties of the films. Ginger oil resulted in lipid droplet aggregation observable by Scanning Electron Microscopy in dried films, surface irregularities and gloss decrease. Neither of the oils improved the ability of sodium caseinate films to act as protection against lipid oxidation, despite the fact that, in a spectrophotometric method, isolated cinnamon oil proved to be very a strong antioxidant.