Journal of Food Processing & Technology

Impact of polyphenol addition on the total phenolic content and antioxidant capacity of acidified milk gels

4^th International Conference and Exhibition on Food Processing & Technology

August 10-12, 2015 London, UK

Mukaddes Kilic Bayraktar1, Niamh B Harbourne2 and Colette C Fagan1

Posters-Accepted Abstracts: J Food Process Technol

Abstract:

Recently, several studies have examined the effect of dairy proteins on the total phenolic content (TPC) and antioxidant capacity
(AC) of polyphenol rich foods. However, the impact of processing conditions on these properties is not fully understood. The
objective of this study was to determine the impact of inclusion of polyphenols in milk prior to acidified milk gel production. A
heat treatment, typically used in yoghurt manufacture (85ºC for 30 min) was applied to pasteurised skimmed milk. Four sources
of phenolic compounds (green tea, white grape, tannic acid, gallic acid) were then incorporated into either the heated or non-heat
treated milk samples (1 mg ml-1 (v/v)). Acidified milk gels were produced from the heat treated milk samples using 2.1% GDL at
30°C for 3 hours. The milk samples and gels (n=45) were also analysed for TPC and AC in triplicate. As expected TPC and AC of the
acid gels containing polyphenols were all significantly higher than the control gel which contained no PP (P<0.05). However, TPC
and AC of the gelled samples were significantly lower (p<0.01) than the ungelled milk samples. The reason might be that polyphenols
are very tightly bound and acid coagulation reduced the level of extractable polyphenols. Non-heat treated milk had no effect of TPC
and AC of milk-polyphenol (MP) mixtures except tannic acid whereas heated milk sample significantly decreased TPC and AC of
MP mixtures except TPC of gallic acid sample. This research can facilitate optimisation of processing conditions to maximise the
nutritional content of dairy products.

Biography :

Mukaddes Kilic Bayraktar is pursuing his PhD in the University of Reading in Food and Nutritional Sciences as scholarship student from Turkey Ministry of Education. He
completed his master’s education at same University and department. His research is related to incorporation of polyphenols in dairy products and examines the effects of
processing conditions on their phenolic content and functional properties of milk proteins.