Article

Effect of Coatings of Silver Nanoparticles and Gum Arabic on Physicochemical and Microbial Properties of Green Bell Pepper ( C apsicum annuum ): Effect of Nanosilver and Gum Arabic Coatings on Bell Pepper

Article

Effect of Coatings of Silver Nanoparticles and Gum Arabic on Physicochemical and Microbial Properties of Green Bell Pepper ( C apsicum annuum ): Effect of Nanosilver and Gum Arabic Coatings on Bell Pepper

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Abstract

The main objective of this work was to study the effects of gum Arabic and silver nanoparticles on the quality of green bell peppers during 21 days of storage. Gum Arabic in aqueous solution of 10%, silver nanoparticles and silver nanoparticles–gum Arabic solution blend, coatings were formed directly on the surface of green bell peppers (Capsicum annuum) and were placed in incubators at 7 and 20C with a relative humidity of about 85%. Fruit quality was evaluated by weight loss, firmness retention, ascorbic acid content, surface color development and microbial decay. Gum Arabic coating presented lower ascorbic acid degradation, weight loss and textural damage but did not affect total aerobic count. Silver nanoparticles hindered microbial decay while did not prevent ascorbic acid decomposition, weight loss and firmness loss. Gum Arabic combined with silver nanoparticles significantly hindered microorganisms' growth and physicochemical losses and showed the best performance for enhancing the shelf life of green bell peppers.Practical ApplicationsThis study indicated that gum Arabic coating hinders water loss, texture softening and vitamin C decomposition, and silver nanoparticles have antimicrobial effects; thus, combination of these two materials results in development of a coating, which improves the nutritional value and marketability of green bell peppers.

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... Earlier, 2 Journal of Food Quality tomatoes coated with gum arabic and kept at 20 ∘ C up to 20 days showed improved quality without production of any spoilage or off-flavors [19]; meanwhile, gum arabic coating in sweet cherries delayed the ripening process and off-flavor development [20]. In another study, gum arabic coating reduced textural damage and decay of green bell pepper [21], whereas gum arabic in combination with silver nanoparticles inhibited microbial growth and increased shelf life of green bell peppers [22]. A recent report showed that gum arabic along with calcium chloride enhanced low temperature tolerance in mango by improving the antioxidant defense system and reducing oxidative damage of mango fruit [23]. ...
... Previously, gum arabic application maintained higher ascorbic acid content in tomato slices [50]. Our results are also in agreement with the findings of Hedayati and Niakousari [22] who reported that gum arabic significantly reduced loss in ascorbic acid contents in green bell pepper. Moreover, the linear increase in pH might be ascribed to biochemical, structural, and physiological alterations taking place during respiration. ...
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... Green bell peppers are perishable products and their keeping quality is relatively low. The main physiological factors that negatively affect the postharvest quality of pepper are pathological factors, water loss and chilling injury (Hedayati and Niakousari, 2015) There are many methods commonly used for bell pepper physical quality inspection: grading machine based on imaging and near infra red which can grade bell peppers based on their size, color, shape and their biological properties including cultivar, season, maturity level and geographical origin . As well as for nutritional monitoring of green pepper during storage: quantification of total acidity, total soluble solid content, protein content, proline content, catalase activity, peroxidase activity, total antioxidant activity, chlorophyll content and capsaicin content (Patel N. et al., 2019) those methods somehow having disadvantages of being destructive, time consuming and expensive. ...
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... They reported that using a combination of active coating with PP bags prolonged the shelf-life of carrots for about 70 days compared with 4 days for the uncoated samples. In another study, Hedayati et al. [66] investigated the efficiency of AgNPs dispersed in gum arabic-based coating to extend the shelf-life of green bell peppers. After 21 days of storage at both tested temperatures 7 °C and 20 °C, the coating significantly inhibited the growth of aerobic microorganisms when compared to uncoated samples. ...
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... Se han empleado diversas estrategias de envasado para prolongar la vida de anaquel de algunos tipos de chiles del género Capsicum annuum. Entre estas estrategias se han implementado recubrimientos de ácido giberélico, goma arábiga, quitosano o envasados en atmósferas modificadas (Chitravathi, Kallepalli, Chauhan & Kizhakkedath, 2020;Hedayati & Niakousari, 2015;Hernández-López, Ventura-Aguilar, Correa-Pacheco, Bautista-Baños & Barrera-Necha, 2020;Panigrahi, Gheewala, Patel, Patel & Gantait, 2017;Singh, Giri & Kotwaliwale, 2014;Xing et al., 2011). Sin embargo, la mayoría de los agricultores, transportistas y consumidores no pueden pagar los costos de mantenimiento de las instalaciones de almacenamiento atmosférico controlado o implementar el empleo de recubrimientos o películas comestibles, por lo que es necesario desarrollar sistemas económicos y viables para 2021 https://doi.org/10.22201/fesz.23958723e.2021.365 ...
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... 346 Hedayati et al prepared surfactantcoated nanoparticles (gum Arabic containing silver nanoparticles and a nonionic surfactant (glyceryl monostearate [ Figure 1]). 347 They reported that coating green bell pepper with this product protected the antioxidant (vitamin C) in the green bell pepper from dehydration and microbial spoilage and maintained marketable quality even after 21-days of storage. Since silver nanoparticles need to be in a dispersed state to exert their antibacterial effect, the approach of coating their surface with a non-ionic surfactant and dispersing them in a system is widely used. ...
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... Fruit post-harvest: edible coatings of 10% Gum Arabic signifi cantly delayed changes in fi rmness, weight, soluble solids, ascorbic acid, titratable acidity, percentage decay and colour development of tomato during 20 days storage (Asgar et al., 2013). Gum Arabic in aqueous solution of 10% combined with silver nanoparticles signifi cantly hindered the growth of microorganisms and physicochemical losses, and showed the best performance for enhancing the shelf life of green bell peppers (Hedayati and Niakousari, 2015). Application of GA 10% coating combined with CA 3% might be a simple and eff ective technique for preserving mango fruit quality during low temperature storage (Ghulam et al., 2015). ...
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This paper presents a simple method that shows how digital imaging and software analysis can be combined for color measurement. The results showed that L∗, a∗ and b∗ values from Hunter colorimeter and the digital imaging method had appropriate correlation with R2 of greater than 0.98, however color values obtained from digital imaging method can be used only to monitor the trend of color changes and relative comparison and there is a noticeable difference between L∗, a∗ and b∗ from digital imaging and values of Hunterlab colorimeter. By using equations presented in this paper, L∗, a∗ and b∗ values obtained from digital imaging method can be successfully converted to Hunterlab color values. Changes in color of Mazafati date during ripening by hot acetic acid solution were monitored by use of this method. L∗, a∗, and b∗ values of the samples decreased during ripening.
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Quality of bell peppers after harvest is largely influenced by water loss from the fruit. The objective of this study was to determine the effect of fruit fresh weight, size, and stage of ripeness on the rate of water loss and permeance to water vapor. Fruit diameter was correlated with fresh weight, and surface area was associated with fresh weight and diameter. Fruit surface area decreased logarithmically with increases in fruit size, with smaller fruit showing larger changes in surface area than larger fruit. Mean water loss rate for individual fruit and permeance to water vapor declined with increases in fruit size and as fruit ripeness progressed. Fruit surface area/fresh weight ratio and rate of water loss were both highest in immature fruit and showed no differences between mature green and red fruit. In mature fruit, permeance to water vapor for the skin and calyx were 29 µmol m−2 s−1 kPa−1 and 398 µmol m−2 s−1 kPa−1, respectively. About 26% of the water loss in mature fruit occurred through the calyx. There was a decline in firmness, water loss rate, and permeance to water vapor of the fruit with increasing fruit water loss during storage. Copyright © 2006 Society of Chemical Industry
Article
Branchlets of broccoli (Brassica oleracea L.) were used to examine ethylene-stimulated chlorophyll catabolism. Branchlets treated with: 1) air (CK); 2) 1 LL–1 1-methylcyclopropene (1-MCP) for 14 hr at 20 C; 3) 1000 LL–1 ethylene (C2H4) for 5 hr at 20 C; or 4) 1-MCP then C2H4, were stored in the dark at 20 C for up to 3 d. Chlorophyll (Chl) content and branchlet hue angle decreased during the storage period and 1-MCP treatment delayed this change. Chl degradation in broccoli was accelerated by exposure to C2H4, especially for Chl a. Prior treatment with 1-MCP prevented degreening stimulated by C2H4. Lipoxygenase activity was not altered by any of the treatments, however, 1-MCP with or without ethylene resulted in reduced activity of chlorophyllase (Chlase) and peroxidase (POD). Exposure to C2H4 stimulated Chlase activity and extended the duration of high POD activity. Treatment with 1-MCP followed by C2H4 resulted in reduced POD activity and delayed the increase in Chlase activity. The results suggest chlorophyll in broccoli can be degraded via the POD – hydrogen peroxide system. Exposure to C2H4 enhances activity of Chlase and extends the duration of high POD activity, and these responses may accelerate degreening. Treatment with 1-MCP delays yellowing of broccoli, an effect that may be due to the 1-MCP-induced reduction in POD and Chlase activities.
Article
Silver nanoparticles (AgNP) are among the fastest growing product categories in the nanotechnology industry. Despite the importance of AgNP in consumer products and clinical applications, relatively little is known regarding AgNP toxicity and its associated risks. We investigated the effects of AgNP on gene expression in the mouse brain using Affymetrix Mouse Genome Arrays. C57BL/6 mice were exposed to AgNP (geometric mean diameter, 22.18±1.72nm; 1.91×107 particles/cm3) for 6h/day, 5days/week using the nose-only exposure system for 2weeks. Total RNA isolated from the cerebrum and cerebellum was subjected to hybridization. From over 39,000 probe sets, 468 genes in the cerebrum and 952 genes in the cerebellum were identified as AgNP-responsive (one-way analysis of variance; p<0.05). The largest groups of gene products affected by AgNP exposure included 73 genes in the cerebrum and 144 genes in the cerebellum. AgNP exposure modulated the expression of several genes associated with motor neuron disorders, neurodegenerative disease, and immune cell function, indicating potential neurotoxicity and immunotoxicity associated with AgNP exposure. Real-time PCR data for five genes analyzed from whole blood showed good correlation with the observed changes in the brain. Following rigorous validation and substantiation, these genes may assist in the development of surrogate markers for AgNP exposure and/or toxicity. KeywordsBrain-Inhalation-Mice-Microarray-Silver nanoparticles-Toxicity-EHS-Nanomedicine
Article
Effect of chitosan–oil coating on qualitative properties of sweet pepper (Capsicum annuum L.) stored at 8 °C for 35 days was investigated. The chitosan–oil coating treatment exhibited the best control effect on decay (below 5%). At the end of storage, samples treated with chitosan-oil coatings maintained good sensory acceptability, whereas the sensory quality of control samples became unacceptable. The higher activities of scavenger antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), in treated peppers at the 35th day should be contributed to the chitosan–oil coating. Malondialdehyde (MDA) and electrolyte leakage contents in chitosan–oil-coated peppers were increased but were still lower than in control samples. Atomic force microscopy images showed that the surface of sweet pepper without coating treatment was rougher than that of peppers treated with chitosan–oil coating. Our study suggests that chitosan–oil coating might be a promising candidate for enhancing the keeping quality of sweet peppers.
Article
Edible coatings of varying composition were applied on fresh apricots and green peppers. The water and vitamin C losses of these coated fresh foods were followed and compared with those of uncoated ones. The main components of the coating were methyl cellulose (MC) and polyethylene glycol (PEG). Stearic acid (SA) and ascorbic acid (AA) or citric acid (CA) were added to the coating formulation to control the barrier properties toward water and oxygen. It was found that coatings of any composition studied lower the water loss rate of fresh apricots and green peppers. Coating formulation of MC–PEG–SA was the most effective in reducing the water loss. Inclusion of AA or CA in the coating formulation as antioxidants lowered the vitamin C loss.
Article
A novel non-ionic surfactant nanoemulsion designated 8N8 has been tested for its biocidal activity. One percent 8N8 produced effective bactericidal activity against Bacillus cereus, Bacillus subtilis, Haemophilus influenzae, Neisseria gonorrhoeae, Streptococcus pneumoniae, and Vibrio cholerae in 15 minutes. In contrast, most enteric Gram-negative bacteria were resistant to 8N8. One percent 8N8 was also virucidal within 15 minutes for all tested enveloped viruses, including Herpes simplex type 1, influenza A and vaccinia viruses. One percent 8N8 also demonstrated fungistatic activity on Candida albicans. The rapid and non-specific inactivation of vegetative bacteria and enveloped viruses, in addition to its fungistatic activity and low toxicity in experimental animals, makes 8N8 a potential candidate for use as a topical biocidal agent.
Article
Gum arabic, an exudate from Acacia trees, has a unique combination of excellent emulsifying properties and low solution viscosity. These properties make gum arabic very useful in several industries but especially in the food industry where it is used as a flavor encapsulator and stabilizer of citrus oil emulsion concentrates in soft drinks. Gum arabic is a mixture of principally polysaccharides and proteoglycans, the latter being arabinogalactan proteins (AGPs). Gum arabic also contains trace levels of lipids. Our hypothesis is that these lipids are attached to the gum arabic AGPs as glycosylphosphatidylinositol (GPI) lipids, as found in rose and other AGPs, and that these lipids make important contributions to the emulsifying activity of gum arabic. To test this hypothesis, chemical treatments expected to cleave GPI lipid anchors have been applied to gum arabic, and the resulting effects on structure and emulsifying activity have been examined. Treatment of gum arabic with nitrous acid resulted in diminished emulsifying activity, loss of some glucosamine and nitrogen, but very little effect on the principal carbohydrate composition. Treatment with 50% aqueous HF at 0 °C resulted in diminished emulsion properties but also significant loss of arabinosyl residues. The approximately 1–3% subfraction of gum arabic components that adsorb at the surface of oil droplets has higher abundance of GPI linker components, much higher relative lipid content, much higher nitrogen content, and somewhat higher emulsifying action than the whole gum. These results are consistent with roles of both lipid and protein in the emulsifying activity of the gum.
Article
Silver nanoparticles have been formed in fluff pulp and nanostructured Lyocell fibres by immersion in silver nitrate, and a subsequent transformation of the adsorbed silver ions into elementary silver nanoparticles by physical (thermal/UV) or chemical (sodium borohydride) methods. Microscopy revealed that nanoparticles generated by physical methods were regular in shape and efficiently dispersed, while the chemical reduction produced highly aggregated nanoparticles. Nanoparticle size has been found relevant to guarantee high antimicrobial activity, being the samples with big aggregated silver nanoparticles almost inefficient. Indeed a satisfactory correlation between silver ion release and the antimicrobial efficiency against Escherichia coli and Staphylococcus aureus could be confirmed, and furthermore, the highest concentrations tested were efficient to reduce the microbial load in poultry exudates. This work demonstrates that especially designed absorbent materials could be optimised to preserve aseptic conditions during manipulation, leading to feasible applications of a silver based nanotechnology in food technology.
Article
Edible coatings can provide an additional protective coating for fresh products and can also give the same effect as modified atmosphere storage in modifying internal gas composition. Recently, several edible coatings for preserving fruits such as oranges, apples, and grapefruits were successfully applied. But, in some cases, edible coatings were not successful. In fact, fruit quality was worse. The success of edible coatings for fresh products totally depends on the control of internal gas composition. This article is designed to help develop a systematic means of selecting edible coatings to maximize quality and shelf life of fresh fruits and vegetables. Methods will be introduced to select edible coatings based on their gas permeation properties relative to controlling internal gas composition of target products.
Article
The principal physiological factors that negatively impact pepper fruit during shipment and storage and subsequent marketing are water loss and chilling injury. The current study evaluated the effect of harvest methodology on postharvest water loss from sweet bell pepper fruit and the potential relationship between water loss and chilling injury in cold-stored fruit. The influence of cultivar, epicuticular wax, and AOX gene expression on water loss and chilling injury were examined. Our results demonstrated that the degree of water loss in pepper fruit is subject to effects of genotype and pre- and postharvest environments as evidenced by year to year variation in fruit storage attributes. A comparison of pepper fruit harvest methods, wherein peduncles were either torn or cut, showed that harvest method had little effect on percent water loss. Observations on fruit water loss in relation to fruit size suggested that fruit cuticles are the primary barrier to water loss. A clear relationship between epicuticular wax content and fruit water loss was not evident. Cultivars varied in their susceptibility to chilling injury and fruit water loss was positively correlated with the severity of chilling injury. No correlation was found between endogenous AOX transcript levels and cultivar-specific susceptibility to chilling injury. The results illustrate the difficulty of identifying indices correlated with water loss that could be used to develop or identify cultivars with improved storability. We did, however, find that there are significant differences in storage attributes of pepper cultivars and that routine screening for water loss and chilling injury are advantageous for selection of cultivars most suitable for cold-storage.
Article
The aim of this study was to evaluate the effects of a bio-based coating containing silver-montmorillonite nanoparticles combined with modified-atmosphere packaging (MAP) on microbial and sensory quality decay of Fior di latte cheese. Different concentrations of silver nanoparticles (0.25, 0.50, and 1.00 mg/mL) were dispersed in a sodium alginic acid solution (8% wt/vol) before coating the cheese. Modified-atmosphere packaging was made up of 30% CO(2), 5% O(2), and 65% N(2). The combination of silver-based nanocomposite coating and MAP enhanced Fior di latte cheese shelf life. In particular, product stored in the traditional packaging showed a shelf life of about 3 d, whereas coated cheese stored under MAP reached a shelf life of more than 5 d, regardless of the concentration of silver nanoparticles. The synergistic effects between antimicrobial nanoparticles and initial headspace conditions in the package could allow diffusion of dairy products beyond the local area.
Article
To investigate the mechanism of inhibition of silver ions on microorganisms, two strains of bacteria, namely Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), were treated with AgNO(3) and studied using combined electron microscopy and X-ray microanalysis. Similar morphological changes occurred in both E. coli and S. aureus cells after Ag(+) treatment. The cytoplasm membrane detached from the cell wall. A remarkable electron-light region appeared in the center of the cells, which contained condensed deoxyribonucleic acid (DNA) molecules. There are many small electron-dense granules either surrounding the cell wall or depositing inside the cells. The existence of elements of silver and sulfur in the electron-dense granules and cytoplasm detected by X-ray microanalysis suggested the antibacterial mechanism of silver: DNA lost its replication ability and the protein became inactivated after Ag(+) treatment. The slighter morphological changes of S. aureus compared with E. coli recommended a defense system of S. aureus against the inhibitory effects of Ag(+) ions.
Article
Inhibition of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes by grape seed extract (ActiVin) and pine bark extract (Pycnogenol) and the effect of these natural extracts on the oxidative stability of raw ground beef were studied. In an agar dilution test, the MICs of ActiVin and Pycnogenol were determined to be 4.0 mg/ml for 4.43 log CFU per plate of E. coli O157:H7 and 4.0 mg/ml for 4.38 log CFU per plate of L. monocytogenes. In an inhibition curve test, populations of E. coli O157:H7, Salmonella Typhimurium, and L. monocytogenes fell to below the detection limit (10 CFU/ml) after 16 h of incubation. The numbers of E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium declined by 1.08, 1.24, and 1.33 log CFU/g, respectively, in raw ground beef treated with 1% Pycnogenol after 9 days of refrigerated storage. ActiVin (1%) and oleoresin rosemary (1%) resulted in an approximately 1-log CFU/g reduction in the populations of all three pathogens after 9 days. The addition of 1% ActiVin and Pycnogenol contributed to the maintenance of an acidic pH of 5.80 and 5.58, respectively, in raw ground beef. Compared to the control, all treatments increased in L* (lightness), with the exception of ActiVin. ActiVin and oleoresin rosemary had the highest a* (redness) and b* (yellowness) values, respectively. ActiVin most effectively retarded lipid oxidation, followed by Pycnogenol. The results suggest that these natural extracts have potential to be used with other preservative methods to reduce pathogenic numbers, lipid oxidation, and color degradation in ground beef.
Article
The development of new edible coatings with improved functionality and performance for fresh and minimally processed fruits is one of the challenges of the post harvest industry. In the past few years, research efforts have focused on the design of new eco-friendly coatings based on biodegradable polymers, which not only reduce the requirements of packaging but also lead to the conversion of by-products of the food industry into value added film-forming components. This work reviews the different coating formulations and applications available at present, as well as the main results of the most recent investigations carried out on the topic. Traditionally, edible coatings have been used as a barrier to minimize water loss and delay the natural senescence of coated fruits through selective permeability to gases. However, the new generation of edible coatings is being especially designed to allow the incorporation and/or controlled release of antioxidants, vitamins, nutraceuticals, and natural antimicrobial agents by means of the application of promising technologies such as nanoencapsulation and the layer-by-layer assembly.
Official Methods of Analysis
AOAC. 2000. Official Methods of Analysis, 16th Ed., Association of Official Analytical Chemists, Washington, DC.
Genomics-based screening of differentially expressed genes in the brains of mice exposed to silver nanoparticles via inhalation Edible coating effects on postharvest quality of green bell peppers
  • H Y Choi
  • J U Jung
  • E J Yin
  • H Q Kwon
  • J T Kim
  • J E Im
  • H T Cho
  • M H Kim
  • J H Kim
  • B H Lerdthanangkul
LEE, H.Y., CHOI, J.U., JUNG, E.J., YIN, H.Q., KWON, J.T., KIM, J.E., IM, H.T., CHO, M.H., KIM, J.H., KIM, H.Y. and LEE, B.H. 2010. Genomics-based screening of differentially expressed genes in the brains of mice exposed to silver nanoparticles via inhalation. J. Nanopart. Res. 12, 1567–1578. LERDTHANANGKUL, S. and KROCTHA, J.M. 1996. Edible coating effects on postharvest quality of green bell peppers. J. Food Sci. 61, 176–179.
Edible coating effects on postharvest quality of green bell peppers
  • S Lerdthanangkul
  • J M Kroctha
LERDTHANANGKUL, S. and KROCTHA, J.M. 1996. Edible coating effects on postharvest quality of green bell peppers. J. Food Sci. 61, 176-179.