Juices from non-typical edible fruits as health-promoting acidity regulators for food industry

The study verifies the possibility of application of juices from selected fruits characterized by the high antioxidant potential as natural acidity regulators with improved nutritional properties. The tested non-typical fruits included mirabelle plum, sea buckthorn and blue-berried honeysuckle. Beetroot juice whose pH is about 6.0 served as a model food product. Potentiometric titration was used to compare the efficacy of tested juices as acidity regulators with that of citric acid, a widely applied acidity regulator. The antioxidant activity of tested mixtures of juices was determined by spectrophotometric ABTS' (2,2-azinobis-(ethyl-2,3-dihydrobenzothiazoline-6-sulphonic acid) diammonium salt) test and their cytotoxic activity was assessed by MIT (thiazolyl blue tetrazolium bromide) test. The potentiometric titration revealed that the efficacy of the juices proposed as acidity regulators matched that of citric acid. Among the mixtures of beetroot juice and titrants studied, the addition of blue-berried honeysuckle juice ensured the highest antioxidant activity, followed by sea buckthorn and mirabelle plum juices. The same order was observed also for biological activity assessed in HT29 cells. The results of all tests confirmed that studied juices can successfully replace currently used acidity regulators, which may be of special interest in the case of functional foods. (C) 2015 Elsevier Ltd. All rights reserved.