The bacteriocin produced by L. casei isolated from infant stool sample was active against some fo... more The bacteriocin produced by L. casei isolated from infant stool sample was active against some food spoilage and pathogenic organisms including Gram-negative bacteria. The strongest activity was seen against S. aureus. The bacteriocin was sensitive to proteolytic enzyme (trypsin) and heat treatment (60°C for 20 min). The bacteriocin was active to various pH values from 3.0 to 7.0. The bacteriocin producer was found to harbor one plasmid of 4.5 Kb size. These results demonstrate the potential of L. casei strain as an alternative to food preservative in refrigerated foods.
ABSTRACT Alginate coatings can act as carriers of antimicrobials to prolong the shelf stability o... more ABSTRACT Alginate coatings can act as carriers of antimicrobials to prolong the shelf stability of minimally processed fruit. Different concentrations of alginate (1, 1.5, 2% (w/v)) incorporated with bacteriocin (0, 20% (v/v)) as a coating material of minimally processed papaya were evaluated for quality parameters viz. firmness, weight loss, colour, head space gas composition, acidity, total soluble solids and microbial load for a period of 21 days. After 21 days of incubation, coated and uncoated samples showed decreases in O2 levels and acidity percentage which were 1.8 and 2.7 times more in uncoated as compared to the coated samples, respectively. The level of CO2 increase was 1.7 times higher in uncoated samples as compared to the coated samples. High respiration rate in uncoated samples led to increases in TSS values, firmness and weight loss. On the other hand, the alginate coating (with or without bacteriocin) acted as a barrier to water vapour transmission and gas exchange, which hindered changes in TSS values, firmness and weight loss in coated samples, which were 3.8, 8.7 and 7.4 times less than for the uncoated samples, respectively. Decreases in ‘b’ and increases in ‘a’ values were more pronounced in the case of controls and became less prominent with the alginate coating. A decrease in ‘b’ values and concomitant increase in ‘a’ values was due to the change from yellow to red colour, indicating ripening of papaya. Microbial counts by the end of the storage period in the alginate coated sample incorporating bacteriocin were 103 CFU/g as compared to 107 CFU/g in the case of the control. Alginate (2% (w/w)) with bacteriocin could be used to store minimally processed papaya for 3 weeks without compromising physico-chemical qualities or microbial safety.
An in silico approach was used for hydrolysis of sheep milk proteins (α-s1, α-s2, β-casein, κ-Cn,... more An in silico approach was used for hydrolysis of sheep milk proteins (α-s1, α-s2, β-casein, κ-Cn, α-lactalbumin, and β-lactoglobulin) by gastrointestinal enzymes in order to generate bioactive peptides (BAPs) that can inhibit ACE and DPP-IV. Sheep milk proteins showed higher similarity with goat milk proteins. These data were acquired via the Clustal Omega tool to perform sequence alignment analysis. The BIOPEP-UWM database was used to examine the ability of sheep milk protein sequences to generate BAPs, which included a description of their potential bioactivity as well as the frequency of fragments with specified activities. Using the "Enzyme(s) action" tool (BIOPEP-UWM), digestive enzymes pepsin, trypsin, and chymotrypsin, and three enzyme combinations were selected to computationally hydrolyze milk proteins for obtaining information about ACE and DPP-IV inhibitory peptides. Other online programs were used to test potential peptides for bioactivity, toxicity, and physicochemical properties. BAPs produced from PTC-hydrolyzed proteins were analyzed using a peptide ranker, and their inhibitory effects on ACE and DPP-IV were determined using molecular docking. Consequently, the results of molecular docking analysis show that the peptide PSGAW (αS1-Cn f155-159) binds to DPP-IV with binding energy (-8.9 kcal/mol). But in the case of ACE, two potential BAPs were selected: QPPQPL (β-Cn f161-166) and PSGAW. These two BAPs revealed a higher binding affinity for ACE with a binding energy of -9.8 kcal/mol. Thus, the results showed that sheep milk proteins were a promising source of antidiabetic and hypotensive peptides. However, experimental and pre-clinical studies are necessary to assay their therapeutic effects. PRACTICAL APPLICATIONS: Sheep milk proteins are known as a high-quality milk protein resource. Effective enzymatic hydrolysis of sheep milk proteins can release bioactive peptides and also release potential ACE and DPP-IV inhibitory peptides. This in silico study specifies a theoretical root for sheep milk proteins as a novel source of potential bioactive peptides and may offer guidance for invitro hydrolysis of proteins for the production of bioactive peptides valuable for human consumption.
This study presents, antimicrobial activity of bioactive peptides derived from fermentation of so... more This study presents, antimicrobial activity of bioactive peptides derived from fermentation of soy milk along with their production by 'Lactobacillus plantarum' C2 strain. Bioactive peptides are specific fragment of protein, can be released by fermentation, upon release they may act as antimicrobial, antioxidant, antihypertensive, immunomodulatory and hypocholesterolemic activities. LP C2 showed very good growth in soy milk by increasing their count and acidity significantly, consequently pH dropped. Ultrafiltration was used for the separation of peptides and their peptide contents analyzed by OPA assay. 10kDa fraction was found high in peptide (655.128 +- 2.95 mug/ml). Antimicrobial activity of bioactive peptide fractions was checked by agar well diffusion method and found that 5 kDa showed highest activity against all the pathogens with highest inhibition against 'E.coli' (12 +- 0.57) followed by 'S. dysenteriae' (11 +- 0.57), 'L. monocytogenous' (10 0.57) and 'B. cereus' (10 +- 0.57 mm). However it was observed that unfractionated sample high in antimicrobial activity, may be due to combined effect of all the fractions.
Journal of the Science of Food and Agriculture, Jun 6, 2014
Lactobacillus rhamnosus C6 strain showed higher β-glucosidase activity as well as biotransformati... more Lactobacillus rhamnosus C6 strain showed higher β-glucosidase activity as well as biotransformation of isoflavones from glycones (daidzin and genistin) to aglycones (daidzein and genistein) in soymilk. However, L. rhamnosus C2 and Lactobacillus casei NCDC297 also exhibited similar activity during soymilk fermentation. These three strains can be selected for the development of functional fermented soy foods enriched with aglycone forms of isoflavones, such as soy yoghurt, soy cheese, soy beverages and soy dahi. The study determined β-glucosidase activity of probiotic Lactobacillus cultures for bioconversion of isoflavones to aglycones in fermenting soymilk medium. Soymilk was fermented with six strains (L. rhamnosus C6 and C2, L. rhamnosus NCDC19 and NCDC24 and L. casei NCDC17 and NCDC297) at 37 °C for 12 h. The highest β-glucosidase activity and isoflavone bioconversion after 12 h occurred by L. rhamnosus C6 culture during fermentation in soymilk. Increased isoflavone aglycone content in fermented soymilk is likely to improve the biological functionality of soymilk (e.g. antioxidant activity, alleviation of hormonal disorders in postmenopausal women, etc.). Lactobacillus rhamnosus C6 culture can be used for the development of functional fermented soy-based products.
The bacteriocin produced by L. casei isolated from infant stool sample was active against some fo... more The bacteriocin produced by L. casei isolated from infant stool sample was active against some food spoilage and pathogenic organisms including Gram-negative bacteria. The strongest activity was seen against S. aureus. The bacteriocin was sensitive to proteolytic enzyme (trypsin) and heat treatment (60°C for 20 min). The bacteriocin was active to various pH values from 3.0 to 7.0. The bacteriocin producer was found to harbor one plasmid of 4.5 Kb size. These results demonstrate the potential of L. casei strain as an alternative to food preservative in refrigerated foods.
ABSTRACT Alginate coatings can act as carriers of antimicrobials to prolong the shelf stability o... more ABSTRACT Alginate coatings can act as carriers of antimicrobials to prolong the shelf stability of minimally processed fruit. Different concentrations of alginate (1, 1.5, 2% (w/v)) incorporated with bacteriocin (0, 20% (v/v)) as a coating material of minimally processed papaya were evaluated for quality parameters viz. firmness, weight loss, colour, head space gas composition, acidity, total soluble solids and microbial load for a period of 21 days. After 21 days of incubation, coated and uncoated samples showed decreases in O2 levels and acidity percentage which were 1.8 and 2.7 times more in uncoated as compared to the coated samples, respectively. The level of CO2 increase was 1.7 times higher in uncoated samples as compared to the coated samples. High respiration rate in uncoated samples led to increases in TSS values, firmness and weight loss. On the other hand, the alginate coating (with or without bacteriocin) acted as a barrier to water vapour transmission and gas exchange, which hindered changes in TSS values, firmness and weight loss in coated samples, which were 3.8, 8.7 and 7.4 times less than for the uncoated samples, respectively. Decreases in ‘b’ and increases in ‘a’ values were more pronounced in the case of controls and became less prominent with the alginate coating. A decrease in ‘b’ values and concomitant increase in ‘a’ values was due to the change from yellow to red colour, indicating ripening of papaya. Microbial counts by the end of the storage period in the alginate coated sample incorporating bacteriocin were 103 CFU/g as compared to 107 CFU/g in the case of the control. Alginate (2% (w/w)) with bacteriocin could be used to store minimally processed papaya for 3 weeks without compromising physico-chemical qualities or microbial safety.
An in silico approach was used for hydrolysis of sheep milk proteins (α-s1, α-s2, β-casein, κ-Cn,... more An in silico approach was used for hydrolysis of sheep milk proteins (α-s1, α-s2, β-casein, κ-Cn, α-lactalbumin, and β-lactoglobulin) by gastrointestinal enzymes in order to generate bioactive peptides (BAPs) that can inhibit ACE and DPP-IV. Sheep milk proteins showed higher similarity with goat milk proteins. These data were acquired via the Clustal Omega tool to perform sequence alignment analysis. The BIOPEP-UWM database was used to examine the ability of sheep milk protein sequences to generate BAPs, which included a description of their potential bioactivity as well as the frequency of fragments with specified activities. Using the "Enzyme(s) action" tool (BIOPEP-UWM), digestive enzymes pepsin, trypsin, and chymotrypsin, and three enzyme combinations were selected to computationally hydrolyze milk proteins for obtaining information about ACE and DPP-IV inhibitory peptides. Other online programs were used to test potential peptides for bioactivity, toxicity, and physicochemical properties. BAPs produced from PTC-hydrolyzed proteins were analyzed using a peptide ranker, and their inhibitory effects on ACE and DPP-IV were determined using molecular docking. Consequently, the results of molecular docking analysis show that the peptide PSGAW (αS1-Cn f155-159) binds to DPP-IV with binding energy (-8.9 kcal/mol). But in the case of ACE, two potential BAPs were selected: QPPQPL (β-Cn f161-166) and PSGAW. These two BAPs revealed a higher binding affinity for ACE with a binding energy of -9.8 kcal/mol. Thus, the results showed that sheep milk proteins were a promising source of antidiabetic and hypotensive peptides. However, experimental and pre-clinical studies are necessary to assay their therapeutic effects. PRACTICAL APPLICATIONS: Sheep milk proteins are known as a high-quality milk protein resource. Effective enzymatic hydrolysis of sheep milk proteins can release bioactive peptides and also release potential ACE and DPP-IV inhibitory peptides. This in silico study specifies a theoretical root for sheep milk proteins as a novel source of potential bioactive peptides and may offer guidance for invitro hydrolysis of proteins for the production of bioactive peptides valuable for human consumption.
This study presents, antimicrobial activity of bioactive peptides derived from fermentation of so... more This study presents, antimicrobial activity of bioactive peptides derived from fermentation of soy milk along with their production by 'Lactobacillus plantarum' C2 strain. Bioactive peptides are specific fragment of protein, can be released by fermentation, upon release they may act as antimicrobial, antioxidant, antihypertensive, immunomodulatory and hypocholesterolemic activities. LP C2 showed very good growth in soy milk by increasing their count and acidity significantly, consequently pH dropped. Ultrafiltration was used for the separation of peptides and their peptide contents analyzed by OPA assay. 10kDa fraction was found high in peptide (655.128 +- 2.95 mug/ml). Antimicrobial activity of bioactive peptide fractions was checked by agar well diffusion method and found that 5 kDa showed highest activity against all the pathogens with highest inhibition against 'E.coli' (12 +- 0.57) followed by 'S. dysenteriae' (11 +- 0.57), 'L. monocytogenous' (10 0.57) and 'B. cereus' (10 +- 0.57 mm). However it was observed that unfractionated sample high in antimicrobial activity, may be due to combined effect of all the fractions.
Journal of the Science of Food and Agriculture, Jun 6, 2014
Lactobacillus rhamnosus C6 strain showed higher β-glucosidase activity as well as biotransformati... more Lactobacillus rhamnosus C6 strain showed higher β-glucosidase activity as well as biotransformation of isoflavones from glycones (daidzin and genistin) to aglycones (daidzein and genistein) in soymilk. However, L. rhamnosus C2 and Lactobacillus casei NCDC297 also exhibited similar activity during soymilk fermentation. These three strains can be selected for the development of functional fermented soy foods enriched with aglycone forms of isoflavones, such as soy yoghurt, soy cheese, soy beverages and soy dahi. The study determined β-glucosidase activity of probiotic Lactobacillus cultures for bioconversion of isoflavones to aglycones in fermenting soymilk medium. Soymilk was fermented with six strains (L. rhamnosus C6 and C2, L. rhamnosus NCDC19 and NCDC24 and L. casei NCDC17 and NCDC297) at 37 °C for 12 h. The highest β-glucosidase activity and isoflavone bioconversion after 12 h occurred by L. rhamnosus C6 culture during fermentation in soymilk. Increased isoflavone aglycone content in fermented soymilk is likely to improve the biological functionality of soymilk (e.g. antioxidant activity, alleviation of hormonal disorders in postmenopausal women, etc.). Lactobacillus rhamnosus C6 culture can be used for the development of functional fermented soy-based products.
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