Proceedings of the National Academy of Sciences, 2006
Lactic acid-producing bacteria are associated with various plant and animal niches and play a key... more Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.
A dipeptidase with prolinase activity from Lactobacillus helveticus CNRZ32, which was designated ... more A dipeptidase with prolinase activity from Lactobacillus helveticus CNRZ32, which was designated PepR, was purified to gel electrophoretic homogeneity and characterized. The NH2-terminal amino acid sequence of the purified protein had 96% identity to the deduced NH2-terminal amino acid sequence of the pepR gene, which was previously designated pepPN, from L. helveticus CNRZ32. The purified enzyme hydrolyzed Pro-Met, Thr-Leu, and Ser-Phe as well as dipeptides containing neutral, nonpolar amino acid residues at the amino terminus. Purified PepR was determined to have a molecular mass of 125 kDa with subunits of 33 kDa. The isoelectric point of the enzyme was determined to be 4.5. The optimal reaction conditions, as determined with Pro-Leu as substrate, were pH 6.0 to 6.5 and 45 to 50 degrees C. The purified PepR had a Km of 4.9 to 5.2 mM and a Vmax of 260 to 270 mumol of protein per min/mg at pH 6.5 and 37 degrees C. The activity of purified PepR was inhibited by Zn2+ but not by other...
Abstract Listeria innocua (ATCC 33090) was treated with 1 ml/100 ml (pH = 2.58) or 0.5 ml/100 ml ... more Abstract Listeria innocua (ATCC 33090) was treated with 1 ml/100 ml (pH = 2.58) or 0.5 ml/100 ml (pH = 2.77) acetic acid in 0.9 g/100 ml saline or in tryptic soy broth with 0.6 g/100 ml yeast extract (TSBYE) containing 1 ml/100 ml acetic acid (pH = 4.13) for up to 63 h at 37 °C. Survival curves for acid treated cells had biphasic shapes which indicated that subpopulations of L. innocua had different levels of sensitivity to acetic acid. Fourier transform infrared (FT-IR) spectra (1800–900 cm −1 ) showed changes in bands for proteins, lipids, DNA/RNA, and carbohydrates occurred between the control (no acid added, at 0 h) and 51 h treatment (pH = 4.13, TSBYE with 1 ml/100 ml acetic acid), indicative of structural damage to cell walls including teichoic acid moieties, cell membranes, DNA/RNA, and to cytoplasmic proteins. Two multivariate statistical methods (principal component analysis (PCA) and partial least squares discriminant regression (PLSR) were applied. These methods successfully classified spectra of bacteria treated at selected time intervals (control, 3 h, 9 h, 21 h and 51 h) indicating the potential FT-IR spectroscopy has for detecting organic acid stress for Listeria spp.
Abstract Colorimetric nanosensors for monitoring food quality and shelf life providea an exciting... more Abstract Colorimetric nanosensors for monitoring food quality and shelf life providea an exciting development with obvious economic benefits. In this study, a colorimetric sensor based on silicon dioxide (SiO2) nanoparticles and Schiff's reagent to detect volatile organic compounds (VOCs) generated by the growth of spoilage bacteria in pasteurized whole milk stored at 7, 13, 15, and 19 °C was developed. Volatile organic compounds formed from microbial growth were detected using solid-phase microextraction (SPME) and gas chromatography. Volatile organic compounds levels were correlated with microbial growth (aerobic plate counts) and color change throughout the shelf-life period. Color changes due to VOCs generated by spoilage bacteria were detected at all storage temperatures except 7 °C. Nanosensor response correlated well with microbial growth in milk. Milk spoilage occurred at 32, 60, and 84 h at 19, 15, and 13 °C, respectively and could be detected colorimetrically. Color change, recorded as total color difference (ΔE) for the nanosensor, correlated well with aerobic plate counts (5.0–7.0 log10 CFU/mL) in milk (R2 = 0.81–0.96). This colorimetric sensor could be incorporated into food packaging to predict remaining shelf-life benefitting consumers as well as manufacturers and retailers and reducing food loss.
Probiotics and antimicrobial proteins, Jan 12, 2018
Longevity of probiotic is the main concern for getting maximum benefits when added in food produc... more Longevity of probiotic is the main concern for getting maximum benefits when added in food product. Bifidobacterium, a probiotic, tends to lose its viability during gastrointestinal track (GIT) transit and storage of food. Their viability can be enhanced through microencapsulation technology. In this study, Bifidobacterium bifidum (B. bifidum) ATCC 35914 was encapsulated by using two experimental plans. In the first plan, chitosan (CH) at 0.6, 0.8, and 1.0% and sodium alginate (SA) at 4, 5, and 6% were used. Based on encapsulation efficiency, 6% sodium alginate and 0.8% chitosan were selected for single coating of the bacteria, and the resulting micro beads were double coated with different concentrations (5, 7.5, and 10%) of whey protein concentrate (WPC) in the second plan. Encapsulation efficiency and GIT tolerance were determined by incubating the micro beads in simulated gastrointestinal juices (SIJ) at variable pH and exposure times, and their release (liberation of bacterial ...
Pathogens exposed to agricultural production environments are subject to multiple stresses that m... more Pathogens exposed to agricultural production environments are subject to multiple stresses that may alter their survival under subsequent stress conditions. The objective of this study was to examine heat and starvation stress response of Escherichia coli O157:H7 strains isolated from agricultural matrices. Seven E. coli O157:H7 isolates from different agricultural matrices—soil, compost, irrigation water, and sheep manure—were selected, and two ATCC strains were used as controls. The E. coli O157:H7 isolates were exposed to heat stress (56°C in 0.1% peptone water for up to 1 h) and starvation (in phosphate-buffered saline at 37°C for 15 days), and their survival was examined. GInaFiT freeware tool was used to perform regression analyses of the surviving populations. The Weibull model was identified as the most appropriate model for response of the isolates to heat stress, whereas the biphasic survival curves during starvation were fitted using the double Weibull model, indicating t...
Kefir is a fermented dairy beverage produced by the actions of the microflora encased in the &... more Kefir is a fermented dairy beverage produced by the actions of the microflora encased in the "kefir grain" on the carbohydrates in the milk. Containing many bacterial species already known for their probiotic properties, it has long been popular in Eastern Europe for its purported health benefits, where it is routinely administered to patients in hospitals and recommended for infants and the infirm. It is beginning to gain a foothold in the USA as a healthy probiotic beverage, mostly as an artisanal beverage, home fermented from shared grains, but also recently as a commercial product commanding shelf space in retail establishments. This is similar to the status of yogurts in the 1970s when yogurt was the new healthy product. Scientific studies into these reported benefits are being conducted into these health benefits, many with promising results, though not all of the studies have been conclusive. Our review provides an overview of kefir's structure, microbial profile, production, and probiotic properties. Our review also discusses alternative uses of kefir, kefir grains, and kefiran (the soluble polysaccharide produced by the organisms in kefir grains). Their utility in wound therapy, food additives, leavening agents, and other non-beverage uses is being studied with promising results.
ABSTRACT This study determined specificities of aminopeptidase N (PepN), endopeptidase E (PepE), ... more ABSTRACT This study determined specificities of aminopeptidase N (PepN), endopeptidase E (PepE), endopeptidase O (PepO), endopeptidase O2 (PepO2), and endopeptidase O3 (PepO3), from Lactobacillus helveticus WSU19 on the αs1-CN f1-23 peptide, formed by residual chymosin during cheese ripening. Cell-free extracts (CFEs) were prepared from Escherichia coli DH5α derivatives expressing peptidase genes of Lb. helveticus WSU19. The αs1-CN f1-23 peptide was digested by CFEs under cheese ripening conditions. Degradation pattern was analyzed qualitatively using MALDI-TOF mass spectrometry. PepN exhibited activity on αs1-CN f1-23 only in the presence of an endopeptidase, particularly PepO-like endopeptidases. PepO, PepO2, and PepO3 cleaved αs1-CN f1-23 predominantly at Glu14–Val15, forming the bitter peptide αs1-CN f1-14. PepE cleaved αs1-CN f1-23 primarily at Lys3–His4, suggesting a role for PepE in degrading bitter peptides from the N-terminus of αs1-CN f1-23. Combinations of PepE/PepO and PepE/PepO2 were determined to have the potential to decrease the accumulation of αs1-CN f1-14.
Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin ga... more Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin gallate (EGCG), 50 and 250 ppm w/w) and green tea powder (1% and 20% w/w of gelatin) were tested for tensile strength, elastic modulus, and elongation, and oxygen and water vapor transmission rates, in vitro antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and effect on stabilizing cod-liver oil held under mild thermal abuse conditions. Cod-liver oil overlaid with films was stored at 40 °C for 20 d and analyzed for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Antioxidant activity was retained in films containing green tea powder, but was reduced (P < 0.05) in EGCG films (20 d, 23 °C). Water vapor transmission rate of the films incorporated with antioxidants did not change significantly (P > 0.05), but the oxygen transmission rate for films with 50 ppm EGCG and 20% green tea powder was significant (P < 0.05). Other physical properties varied with antioxidant incorporation. The TBARS and PV of control oil increased from 0.05 ± 0.01 to 4.71 ± 0.30 g MDA/kg oil and from 3.6 ± 0.2 to 178.3 ± 24.5 millieq peroxides/kg oil, respectively, after 20 d. For cod-liver oil covered with control or antioxidant-containing films, TBARS remained below 0.37 g MDA/kg oil and PV below 7 millieq peroxides/kg oil. Incorporation of antioxidants to the films did not reduce oil oxidation (P > 0.05) at the levels tested and this was confirmed by activation energy calculations. The rate of oil oxidation was more dependent upon the inherent oxygen barrier property of the films than the presence of antioxidants. This research has the potential to enhance the utilization of fish skins, a valuable food processing by-product, as edible films with natural antioxidants to extend the shelf life of foods. The film physical properties and barrier to oxygen and water are investigated.
Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin ga... more Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin gallate (EGCG), 50 and 250 ppm w/w) and green tea powder (1% and 20% w/w of gelatin) were tested for tensile strength, elastic modulus, and elongation, and oxygen and water vapor transmission rates, in vitro antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and effect on stabilizing cod-liver oil held under mild thermal abuse conditions. Cod-liver oil overlaid with films was stored at 40 °C for 20 d and analyzed for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Antioxidant activity was retained in films containing green tea powder, but was reduced (P < 0.05) in EGCG films (20 d, 23 °C). Water vapor transmission rate of the films incorporated with antioxidants did not change significantly (P > 0.05), but the oxygen transmission rate for films with 50 ppm EGCG and 20% green tea powder was significant (P < 0.05). Other physical properties varied with antioxidant incorporation. The TBARS and PV of control oil increased from 0.05 ± 0.01 to 4.71 ± 0.30 g MDA/kg oil and from 3.6 ± 0.2 to 178.3 ± 24.5 millieq peroxides/kg oil, respectively, after 20 d. For cod-liver oil covered with control or antioxidant-containing films, TBARS remained below 0.37 g MDA/kg oil and PV below 7 millieq peroxides/kg oil. Incorporation of antioxidants to the films did not reduce oil oxidation (P > 0.05) at the levels tested and this was confirmed by activation energy calculations. The rate of oil oxidation was more dependent upon the inherent oxygen barrier property of the films than the presence of antioxidants. This research has the potential to enhance the utilization of fish skins, a valuable food processing by-product, as edible films with natural antioxidants to extend the shelf life of foods. The film physical properties and barrier to oxygen and water are investigated.
Proceedings of the National Academy of Sciences, 2006
Lactic acid-producing bacteria are associated with various plant and animal niches and play a key... more Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.
A dipeptidase with prolinase activity from Lactobacillus helveticus CNRZ32, which was designated ... more A dipeptidase with prolinase activity from Lactobacillus helveticus CNRZ32, which was designated PepR, was purified to gel electrophoretic homogeneity and characterized. The NH2-terminal amino acid sequence of the purified protein had 96% identity to the deduced NH2-terminal amino acid sequence of the pepR gene, which was previously designated pepPN, from L. helveticus CNRZ32. The purified enzyme hydrolyzed Pro-Met, Thr-Leu, and Ser-Phe as well as dipeptides containing neutral, nonpolar amino acid residues at the amino terminus. Purified PepR was determined to have a molecular mass of 125 kDa with subunits of 33 kDa. The isoelectric point of the enzyme was determined to be 4.5. The optimal reaction conditions, as determined with Pro-Leu as substrate, were pH 6.0 to 6.5 and 45 to 50 degrees C. The purified PepR had a Km of 4.9 to 5.2 mM and a Vmax of 260 to 270 mumol of protein per min/mg at pH 6.5 and 37 degrees C. The activity of purified PepR was inhibited by Zn2+ but not by other...
Abstract Listeria innocua (ATCC 33090) was treated with 1 ml/100 ml (pH = 2.58) or 0.5 ml/100 ml ... more Abstract Listeria innocua (ATCC 33090) was treated with 1 ml/100 ml (pH = 2.58) or 0.5 ml/100 ml (pH = 2.77) acetic acid in 0.9 g/100 ml saline or in tryptic soy broth with 0.6 g/100 ml yeast extract (TSBYE) containing 1 ml/100 ml acetic acid (pH = 4.13) for up to 63 h at 37 °C. Survival curves for acid treated cells had biphasic shapes which indicated that subpopulations of L. innocua had different levels of sensitivity to acetic acid. Fourier transform infrared (FT-IR) spectra (1800–900 cm −1 ) showed changes in bands for proteins, lipids, DNA/RNA, and carbohydrates occurred between the control (no acid added, at 0 h) and 51 h treatment (pH = 4.13, TSBYE with 1 ml/100 ml acetic acid), indicative of structural damage to cell walls including teichoic acid moieties, cell membranes, DNA/RNA, and to cytoplasmic proteins. Two multivariate statistical methods (principal component analysis (PCA) and partial least squares discriminant regression (PLSR) were applied. These methods successfully classified spectra of bacteria treated at selected time intervals (control, 3 h, 9 h, 21 h and 51 h) indicating the potential FT-IR spectroscopy has for detecting organic acid stress for Listeria spp.
Abstract Colorimetric nanosensors for monitoring food quality and shelf life providea an exciting... more Abstract Colorimetric nanosensors for monitoring food quality and shelf life providea an exciting development with obvious economic benefits. In this study, a colorimetric sensor based on silicon dioxide (SiO2) nanoparticles and Schiff's reagent to detect volatile organic compounds (VOCs) generated by the growth of spoilage bacteria in pasteurized whole milk stored at 7, 13, 15, and 19 °C was developed. Volatile organic compounds formed from microbial growth were detected using solid-phase microextraction (SPME) and gas chromatography. Volatile organic compounds levels were correlated with microbial growth (aerobic plate counts) and color change throughout the shelf-life period. Color changes due to VOCs generated by spoilage bacteria were detected at all storage temperatures except 7 °C. Nanosensor response correlated well with microbial growth in milk. Milk spoilage occurred at 32, 60, and 84 h at 19, 15, and 13 °C, respectively and could be detected colorimetrically. Color change, recorded as total color difference (ΔE) for the nanosensor, correlated well with aerobic plate counts (5.0–7.0 log10 CFU/mL) in milk (R2 = 0.81–0.96). This colorimetric sensor could be incorporated into food packaging to predict remaining shelf-life benefitting consumers as well as manufacturers and retailers and reducing food loss.
Probiotics and antimicrobial proteins, Jan 12, 2018
Longevity of probiotic is the main concern for getting maximum benefits when added in food produc... more Longevity of probiotic is the main concern for getting maximum benefits when added in food product. Bifidobacterium, a probiotic, tends to lose its viability during gastrointestinal track (GIT) transit and storage of food. Their viability can be enhanced through microencapsulation technology. In this study, Bifidobacterium bifidum (B. bifidum) ATCC 35914 was encapsulated by using two experimental plans. In the first plan, chitosan (CH) at 0.6, 0.8, and 1.0% and sodium alginate (SA) at 4, 5, and 6% were used. Based on encapsulation efficiency, 6% sodium alginate and 0.8% chitosan were selected for single coating of the bacteria, and the resulting micro beads were double coated with different concentrations (5, 7.5, and 10%) of whey protein concentrate (WPC) in the second plan. Encapsulation efficiency and GIT tolerance were determined by incubating the micro beads in simulated gastrointestinal juices (SIJ) at variable pH and exposure times, and their release (liberation of bacterial ...
Pathogens exposed to agricultural production environments are subject to multiple stresses that m... more Pathogens exposed to agricultural production environments are subject to multiple stresses that may alter their survival under subsequent stress conditions. The objective of this study was to examine heat and starvation stress response of Escherichia coli O157:H7 strains isolated from agricultural matrices. Seven E. coli O157:H7 isolates from different agricultural matrices—soil, compost, irrigation water, and sheep manure—were selected, and two ATCC strains were used as controls. The E. coli O157:H7 isolates were exposed to heat stress (56°C in 0.1% peptone water for up to 1 h) and starvation (in phosphate-buffered saline at 37°C for 15 days), and their survival was examined. GInaFiT freeware tool was used to perform regression analyses of the surviving populations. The Weibull model was identified as the most appropriate model for response of the isolates to heat stress, whereas the biphasic survival curves during starvation were fitted using the double Weibull model, indicating t...
Kefir is a fermented dairy beverage produced by the actions of the microflora encased in the &... more Kefir is a fermented dairy beverage produced by the actions of the microflora encased in the "kefir grain" on the carbohydrates in the milk. Containing many bacterial species already known for their probiotic properties, it has long been popular in Eastern Europe for its purported health benefits, where it is routinely administered to patients in hospitals and recommended for infants and the infirm. It is beginning to gain a foothold in the USA as a healthy probiotic beverage, mostly as an artisanal beverage, home fermented from shared grains, but also recently as a commercial product commanding shelf space in retail establishments. This is similar to the status of yogurts in the 1970s when yogurt was the new healthy product. Scientific studies into these reported benefits are being conducted into these health benefits, many with promising results, though not all of the studies have been conclusive. Our review provides an overview of kefir's structure, microbial profile, production, and probiotic properties. Our review also discusses alternative uses of kefir, kefir grains, and kefiran (the soluble polysaccharide produced by the organisms in kefir grains). Their utility in wound therapy, food additives, leavening agents, and other non-beverage uses is being studied with promising results.
ABSTRACT This study determined specificities of aminopeptidase N (PepN), endopeptidase E (PepE), ... more ABSTRACT This study determined specificities of aminopeptidase N (PepN), endopeptidase E (PepE), endopeptidase O (PepO), endopeptidase O2 (PepO2), and endopeptidase O3 (PepO3), from Lactobacillus helveticus WSU19 on the αs1-CN f1-23 peptide, formed by residual chymosin during cheese ripening. Cell-free extracts (CFEs) were prepared from Escherichia coli DH5α derivatives expressing peptidase genes of Lb. helveticus WSU19. The αs1-CN f1-23 peptide was digested by CFEs under cheese ripening conditions. Degradation pattern was analyzed qualitatively using MALDI-TOF mass spectrometry. PepN exhibited activity on αs1-CN f1-23 only in the presence of an endopeptidase, particularly PepO-like endopeptidases. PepO, PepO2, and PepO3 cleaved αs1-CN f1-23 predominantly at Glu14–Val15, forming the bitter peptide αs1-CN f1-14. PepE cleaved αs1-CN f1-23 primarily at Lys3–His4, suggesting a role for PepE in degrading bitter peptides from the N-terminus of αs1-CN f1-23. Combinations of PepE/PepO and PepE/PepO2 were determined to have the potential to decrease the accumulation of αs1-CN f1-14.
Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin ga... more Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin gallate (EGCG), 50 and 250 ppm w/w) and green tea powder (1% and 20% w/w of gelatin) were tested for tensile strength, elastic modulus, and elongation, and oxygen and water vapor transmission rates, in vitro antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and effect on stabilizing cod-liver oil held under mild thermal abuse conditions. Cod-liver oil overlaid with films was stored at 40 °C for 20 d and analyzed for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Antioxidant activity was retained in films containing green tea powder, but was reduced (P < 0.05) in EGCG films (20 d, 23 °C). Water vapor transmission rate of the films incorporated with antioxidants did not change significantly (P > 0.05), but the oxygen transmission rate for films with 50 ppm EGCG and 20% green tea powder was significant (P < 0.05). Other physical properties varied with antioxidant incorporation. The TBARS and PV of control oil increased from 0.05 ± 0.01 to 4.71 ± 0.30 g MDA/kg oil and from 3.6 ± 0.2 to 178.3 ± 24.5 millieq peroxides/kg oil, respectively, after 20 d. For cod-liver oil covered with control or antioxidant-containing films, TBARS remained below 0.37 g MDA/kg oil and PV below 7 millieq peroxides/kg oil. Incorporation of antioxidants to the films did not reduce oil oxidation (P > 0.05) at the levels tested and this was confirmed by activation energy calculations. The rate of oil oxidation was more dependent upon the inherent oxygen barrier property of the films than the presence of antioxidants. This research has the potential to enhance the utilization of fish skins, a valuable food processing by-product, as edible films with natural antioxidants to extend the shelf life of foods. The film physical properties and barrier to oxygen and water are investigated.
Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin ga... more Trout-skin (Oncorhynchus mykiss) gelatin-based films containing antioxidants (epigallocatechin gallate (EGCG), 50 and 250 ppm w/w) and green tea powder (1% and 20% w/w of gelatin) were tested for tensile strength, elastic modulus, and elongation, and oxygen and water vapor transmission rates, in vitro antioxidant activity using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and effect on stabilizing cod-liver oil held under mild thermal abuse conditions. Cod-liver oil overlaid with films was stored at 40 °C for 20 d and analyzed for peroxide value (PV) and thiobarbituric acid reactive substances (TBARS). Antioxidant activity was retained in films containing green tea powder, but was reduced (P < 0.05) in EGCG films (20 d, 23 °C). Water vapor transmission rate of the films incorporated with antioxidants did not change significantly (P > 0.05), but the oxygen transmission rate for films with 50 ppm EGCG and 20% green tea powder was significant (P < 0.05). Other physical properties varied with antioxidant incorporation. The TBARS and PV of control oil increased from 0.05 ± 0.01 to 4.71 ± 0.30 g MDA/kg oil and from 3.6 ± 0.2 to 178.3 ± 24.5 millieq peroxides/kg oil, respectively, after 20 d. For cod-liver oil covered with control or antioxidant-containing films, TBARS remained below 0.37 g MDA/kg oil and PV below 7 millieq peroxides/kg oil. Incorporation of antioxidants to the films did not reduce oil oxidation (P > 0.05) at the levels tested and this was confirmed by activation energy calculations. The rate of oil oxidation was more dependent upon the inherent oxygen barrier property of the films than the presence of antioxidants. This research has the potential to enhance the utilization of fish skins, a valuable food processing by-product, as edible films with natural antioxidants to extend the shelf life of foods. The film physical properties and barrier to oxygen and water are investigated.
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