Influence of hot and cold break tomato powders on survival of probiotic L. paracasei subsp. paracasei F19, texture profile and antioxidative activity in set-type yoghurts

Abstract

The yoghurt samples enriched with hot and cold break tomato powders (HBT and CBT) were evaluated by monitoring the changes in some physicochemical properties and bacterial viability during storage. Besides, radical scavenging activity, total phenolic contents, and textural parameters of samples were determined. Tomato powders were added at different levels (0.5, 1, 2%) and L. paracasei F19 was used with starter culture in yoghurt production. Total solids and ash content of yoghurt without powders were lower than the others. HBT supplementation significantly increased DPPH and ABTS + scavenging activities and the highest activities were determined in yoghurt samples containing 2% HBT (197.7 g/kg, 4.84 mol trolox/kg respectively). Total phenolic content of samples ranged from 5.00 to 14.92 g GAE/kg. The addition of tomato powders decreased firmness and viscosity and plain yoghurt was found to be more consistence (12161.80 g s) and cohesive (219.50 g). The pH values of samples decreased whereas titratable acidity values increased throughout 21 days of storage and L. pantacasei F19 counts was higher than 10(6) CFU/g at the end of storage.