title: Effect of green tea supplementation on the microbiological, antioxidant, and sensory properties of probiotic milks.
abstract: Green tea and its constituents are known for a wide range of health-promoting properties. They may exert antimicrobial action but without altering lactic acid bacteria. The aim of the present study was to estimate the effect of green tea addition on the selected properties of probiotic milks. Bioyogurts (fermented with ABT-1 coculture ofStreptococcus thermophilus,Lactobacillus acidophilusLA-5,Bifidobacterium animalissubsp.lactisBB-12) and acidophilus milks (fermented with pureL. acidophilusLA-5 culture) with addition of 0, 5, 10, or 15% (v/v) green tea infusion (GTI) were produced and analyzed for the antioxidant capacity by the "diphenyl picrylhydrazyl" (DPPH) and "ferric-reducing antioxidant power" (FRAP) methods, acidity, the count of starter bacteria, and sensory properties at the 1st, 7th, 14th, and 21st day of cold storage. The 15% addition of GTI to the acidophilus milk significantly reduced the lactic acid production during the whole study. The GTI had no impact on the level ofS. thermophilusandB. lactisBB-12 in bioyogurts, and its effect on the count ofL. acidophilusLA-5 depended on the concentration and probiotic milk type. GTI similarly and in a dose-dependent manner enhanced the antioxidant capacity of both milk types. There were no significant differences between the sensory notes received for bioyogurts, whereas acidophilus milks with tea were less appreciated by the panelists. In conclusion, green tea could be successfully used as a functional additive for selected probiotic milks enhancing their health benefits, but the proper selection of tea additive and starter culture is recommended.
authors.affiliation: Faculty of Food Technology, Department of Animal Product Technology, University of Agriculture in Krakow, ul. Balicka 122, 30-149 Krakow, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Najgebauer-Lejko
keywords: Antioxidant activity; Fermented milk; Green tea; Probiotics; Sensory evaluation