RESUMEN
Lactiplantibacillus plantarum OV50 is a novel strain that was isolated from Algerian olives. Prior to its use as a natural biopreservative, OV50 underwent characterization for various functions. OV50 shows no proteolytic, lipolytic, or hemolytic activity. In addition, it is non-cytotoxic to eukaryotic cells and does not exhibit acquired antibiotic resistance. OV50 was tested with Pseudomonas aeruginosa ATCC 27835, Staphylococcus aureus ATCC 6538, Escherichia coli ATCC 8739, and Vibrio cholerae ATCC 14035 in a sardine based-medium at 37 °C and 7 °C. At 37 °C, OV50 completely inhibited the growth of these foodborne pathogens for a maximum of 6 h. At 7 °C, it suppressed their growth for a maximum of 8 days, except for S. aureus ATCC 6538, whose growth was reduced from 4 to 2 log CFU/mL. Microbiological counts, total volatile basic nitrogen (TVB-N), and peroxide values (PV) concentrations were determined in fresh sardines inoculated with OV50 and kept at 7 °C for 12 days. The inoculated sardines showed a significant reduction in TVB-N levels at D8 (34.9 mg/100 g) compared to the control (59.73 mg/100 g) and in PV concentrations at D4 (6.67 meq/kg) compared to the control (11.44 meq/kg), as well as a significant reduction in the numbers of Enterobacterales, Coliforms, Pseudomonas spp., Vibrio spp., and S. aureus At D8 and D12 compared to the control. Taken together, these results indicate that OV50 can improve the microbiological safety, freshness, and quality of sardines.
RESUMEN
The aim of the present study was to optimise the extraction conditions of anthocyanins from strawberry fruits and incorporate them in yoghurt to achieve a natural coloration as well as enrich the product with antioxidants. The response surface methodology (RSM) based on Box-Behnken design was studied to assess the influence of the three factors being agitation speed (400-800 rpm), sample to solvent ratio (0.5-2 g/40 mL), and extraction time (1-15 min) on total anthocyanin content and antioxidant activity of strawberries. According to the results, the linear, quadratic and interaction effects of the studied factors on total anthocyanin content and antioxidant activity were determined by the response surface methodology, and the optimal conditions for anthocyanin extraction were 586 rpm for agitation speed, 1.26 g/40 mL for sample to solvent ratio, and 9.36 min for extraction time. Under these extraction conditions, the total anthocyanin content and antioxidant activity recorded by the two validated models were 38.04 mg C3GE/100 g FW and 21.38 mg AAE/100 g FW, respectively. The enriched natural yoghurt contains anthocyanins with a content of 36.50 µg C3GE/100 g and an antioxidant activity of 21.22 µg AAE/100 g. The anthocyanin enriched yoghurt developed in this study may be considered as a functional food with an interesting source of natural antioxidants, and these anthocyanins can substitute synthetic (industrial) colorants.
