Effects of dehydroquercetine on milk fat stability against oxidation

Dymanics of the oxidative spoilage of milk fat depending on the quantity of dehydroquercetine added was studied. Pure milk fat having minimal indices of oxidative spoilage has been chosen as a model system. Five samples have been prepared on the base of the above mentioned fat: control one and four experimental with dehydroquercetine levels from 0,02 to 0,05 %.Oxidative values were determined under the terms of accelerated oxidative spoilage of the fat at increased temperature 102±1 °С. The degree of oxidation was assessed according to the methodology that characterizes milk fat spoilage in four categories («fresh», «fresh but can not be stored», «doubtful fresh» and «spoiled») depending on the peroxide values. On the first stage the indices were controlled each 2 hours during 8 hours. After 8 hours in the conditions of accelerated spoilage milk fat of the control and experimental samples was characterized as «fresh». Peroxide values of the control sample increased more than 10 times. In the experimental samples this index was 2-3 times lower. It was noted that the trend of slowing down of the oxidative processes in the samples with dehydroquercetine depended on the dose added. In order to detect the inductive period of oxidation to the indices characterizing the fat as «spoiled» the samples were stored at 102±1 °С during additional 16 hours. After that the peroxide values were controlled each 2 hours up to 24 hours holding. During this period (after 24 h) peroxide value in the control sample became 10 times higher than the limit of the induction period. The sample was classified as «spoiled» and was put away. The experimental samples have been studied during 48 hours at 102±1 °C and then during 21 days at 22±1 °С with sampling intervals 3 days. At the beginning of the period all experimental samples were in the category «fresh», after 6 days they came over to the category «fresh but can not be stored» and stayed in the range given up to the end of the trials without reaching oxidative limits. Results of the study confirmed high antioxidant activity of dehydroquercetine in relation to milk fat and reverse dependence of oxidation intensity on concentration. Introduction of the food supplement given in the quantity 0,02 % of the fat mass in the product ensures noticeable antioxidant effect. That’s why 2 times and more increasing of the supplement dose is considered to be of low efficiency and economically non-expedient. Application of dehydroquercetine can be recommended to domestic foods producers. Requirements to buying and usage are given in the intergovernmental GOST 33504-2015 «Food supplements. Dehydroquercetine. Technical regulations» that started to work on 01.01.2017.

dehydroquercetine, peroxide value, oxidative spoilage, milk fat, antioxidant