Kenaf seeds are a promising source of natural preservatives for food applications due to their potential as a substrate to generate peptides with high antibacterial activity. We sought to generate bioactive peptides with antibacterial activity from Kenaf seed proteins via lactofermentation. The ground seeds were defatted and protein extracted using acid precipitation. Kenaf seed protein was fermented with Lactobacillus casei for 72 h at 37 °C, and the antibacterial activity, MIC, and MBC were determined using a 96-well microtiter plate assay. The fermented protein was subjected to fractionation and peptide identification using reversedphase high pressure liquid chromatography and liquid chromatography-mass spectrometry, respectively. The fermented protein showed high antibacterial activity against Salmonella typhimurim, Escherichia coli, Psedomonas aerginosa, Staphylococcus aureus, Bacilus subtilis, and Streptococcus pyogenes. The MIC value was 4 mg/mL against all tested pathogens and the MBC value was 8 mg/mL against S. typhimurium, P. aureginosa, and E. coli and 4 mg/mL against B. subtilis, S. aureus, and S. pyogenes. Fraction 17 demonstrated the strongest antibacterial activity (98%-100%), and five peptides sequences were identified in this fraction. The findings of this study demonstrated high potential for kenaf seed protein fermented using Lactobacillus casei as a source of natural preservatives for a broad range of food applications.
Date fruit (Phoenix dactylifera) have long history in food application due to the nutritional value, pleasant flavour and biological activity. This study aimed at investigating the antimicrobial activity of date fruits fermented with Lactobacillus plantarum ATCC8014. The fermented date fruit was added as ingredient for confectionary making and evaluated for it is effects on the physiochemical properties and shelf life of toffee-like South Asian product (Dodol). The results showed broad range antifungal activity of fermented date fruit towards Aspergillus niger (90.85%), Aspergillus flavus (92.86%) Escherichia coli (13 mm) and Staphylococcus aureus (15 mm). The identified bioactive metabolites included propylene glycol (0.028 mmol mL À1), lactic acid (0.763 mmol mL À1), acetic acid (0.292 mmol mL À1), acetoin (0.046 mmol mL À1) and gamma-Aminobutyric acid (0.041 mmol mL À1). Fermented date fruit (125 g/kg) significantly (p < 0.05) extended the shelf life of Dodol for 19 days at 25 ± 2 C in comparison to the control that showed mould growth after 12 days. The microbial growth was significantly reduced in the modified Dodol. A significant influence was observed in the physiochemical properties for modified Dodol such as increasing moisture and water activity and reducing the product firmness. No significant differences (p ! 0.05) were observed for the consumer acceptability between traditional and modified Dodol. The results indicated that the high antifungal activity is due to the presence of several bioactive metabolites. Moreover, the findings indicated the promising applications of fermented date fruit as functional ingredient to improve quality and the shelf life stability for confectionaries.
BACKGROUND: This study determined the effect of processing conditions on protein extractability from Azolla pinnata fern, and their influence on the physicochemical, structural, techno-functional properties and protein quality.
RESULTS:The protein extraction from A. pinnata fern was optimized through response surface methodology obtaining a maximum yield of 18.93% with a recovery rate of 73.66%. The A. pinnata fern protein concentrate (AFPC) had five protein bands with a molecular weight ranging from 17 to 56 kDa. AFPC contained high ⊎-sheet structure (36.61%), favouring its good thermal properties with three endothermic peaks at 54.28, 86.52 and 166.25 °C. The AFPC scored ≥ 1 for all essential amino acids, except for lysine and histidine. The AFPC exhibited exceptionally high techno-functional properties, particularly for water holding (5.46 g g −1 ) and fat absorption capacity (10.08 g g −1 ), and gelling properties (5% gelation concentration). The AFPC had high in vitro digestibility of 73%, signifying its high availability for human consumption. CONCLUSION: The underexploited A. pinnata fern is a potential source of edible protein, thus a promising nutraceutical or ingredient of functional and health-promoting foods.
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