Determination of Some Quality Characteristics and Rheological Properties of Yoghurts Made Using Cow Milk and Soy Drink Mixture Enriched With Pomegranate Peel Extract

Abstract

This study examined the applicability of pomegranate peel extracts (PPE) and microencapsulated PPE extracts (MPE) in yoghurts which are made with cow's milk and soy drink mixtures. For preparing PPE, pomegranate peel powders were extracted by 50% ethanol in an ultrasonic water bath. PPE was encapsulated by using a spray dryer. Phytochemical composition and antioxidant activity of PPE and MPE were determined and PPE and MPE were added to cow milk and soy drink mixture (4:1) for yoghurt production at 0.5% and 1% rates, respectively. Physicochemical, rheological, microbial and sensory properties of the yoghurt samples stored at 4 & DEG;C were determined during storage. Extract addition affected storage modulus (G') values and lost tangent (tan & delta;) values. The extract additive prevented the growth of yeasts and moulds and extended the shelf life of the samples. The favorable effect of the extract on taste and aroma was determined in sensory tests. The overall acceptability scores for PY1 and MY1 samples increased during the storage time and the higher scores was determined on the 28th days of storage. However, the extract contributed to the loss of textural properties such as syneresis and visible viscosity.