Evaluation of physico-chemical properties of some date varieties and yoghurt made with its syrups

Abstract

Background and Objective: Date is a rich composition of carbohydrates, minerals, dietary fiber, vitamins, fatty acids and amino acids. Date syrup is directly consumed or used as an ingredient in some food formulation such as ice cream, drink, confectionery, bakery products and jam. The purpose of this study was to use the date syrup, extracted from some date varieties cultivated in Egypt (Salma, Magdy and Khalas), to improve the acceptability and nutritional value of yoghurt. Materials and Methods: The date extract was centrifuged at 7,000 rpm for 30 min and concentrated under vacuum at 70EC to obtain one fourth or third of the total extract volume (~25-28% TS). Date syrup (Salma, Magdy and Khalas) was added individually to the standardized milk (~3.0% fat and ~15.0% TS) at rate of 15.0% (as the best percentage according to the pre-experimental) to create 3 treatments (T1, T2 and T3, respectively). The collected data were statistically analyzed by one way-ANOVA using SPSS software program. Results: The results showed that, all date varieties were rich in sugars especially glucose and fructose, minerals especially K, Fe, Na and Mg and vitamin C as well as exhibited antioxidant activity against DPPH•. Date syrup had no significant effect on pH value and whey syneresis of resultant yoghurt compared with control. Also, using date syrup in yoghurt manufacture had no adverse effect but may enhance the viability of starter culture. However, both the viscosity and the whiteness degree have been negatively affected by using the date syrup. Conclusion: It was concluded that the yoghurt made with date syrup was more acceptable (more softness, smoothness and more sweetness) especially that made with Magdy date syrup (T2).