No abstract

Eight lactic acid bacteria strains isolated from traditional fermented foods were investigated for their antioxidant activity against DPPH free radicals, β-carotene bleaching assay and linoleic acid test. L. plantarum LAB 1 at a dose of 8.2 10 9 CFU/ml showed the highest DPPH scavenging activity, with inhibition rate of 57.07 ± 0.57 % and an antioxidant activity (TAA = 43.47±0.663 % and AAC=172.65±5.57), which increase with cell concentrations. When L. plantarum LAB 1 was administered to oxidative enzymes, residual activities decreased significantly with cell concentrations. The use of L. plantarum LAB 1 on olives process, favours the increase of the antioxidant activity (24 %). HPLC results showed a significant increase of orthodiphenols (74 %). Viable cells of strain were implicated directly on minimum media growth with 500 mg/l of olive phenolic compounds. Results showed an increase in their antioxidant activity. CG-SM analysis, identify the presence of compounds with higher antioxidant activity as vinyl phenol and hydroxytyrosol.

The aim of this work was to explore the use of protein isolate from tomato seed enriched with the sucrose and the ascorbic acid as a medium for the growth of kefir mixture culture to develop a new non-dairy functional food. Unstructured mathematical and logistic models were proposed to describe cell growth, kefiran production, nutriment consumption and antioxidant activity. It was found that the maximal cell mass in the culture reached 8.38 g L after 24 h of fermentation. A significant amount of kefiran was also produced (0.65 g L). The kefir culture growth significantly decreased protein content and enhanced the antioxidant activity during varied fermentation through the production of bio active peptides. After 24 h of fermentation, IC value for protein isolate was estimated to be about 10.48 µg mL. The proposed models adequately described the changes during fermentation and as observed as a promising approach for the formulation of tomato seed-based functional foods. The preservation of the isolate was also investigated through a spray-drying process. The effect of spray-drying on the viability of lactic acid bacteria and stability of protein content and the antioxidant activity of the powder was also carried out. Results showed that the spray-drying method has great potential for the synthesis of powder from the fermented isolate that are rich in desirable properties. However, it was appropriate to preserve the powder for 10 days at 37 °C for the preservation of protein functionality.