Sensory, rheological and chemical characteristics during storage of set type full fat yoghurt fortified with barley β-glucan.

Abstract

β-Glucan, is a soluble dietary fiber and is obtained from number of sources including cereals. It possesses the nutraceutical characteristics and acts as functional bioactive ingredient in the fermented dairy product including yoghurt. In this concern, β-glucan isolated from barley having purity of (91.52%) was incorporated in different proportions (0.5, 1, 1.5 and 2%, w/v) during the full fat yoghurt preparation. The analysis of β-glucan carried out initially, indicated that the viscosity, water binding capacity, swelling power and solubility values were 92Pas, 3.17g/g, 18.50g/g and 3%, respectively, whereas, the total antioxidant activity obtained in terms of DPPH free radical scavenging activity was 27%. Based on these characteristics β-glucan extract had been considered as the choicest material for set type products like yoghurt. Thereafter, physiochemical, rheological and sensory characteristics of β-glucan incorporated yoghurt were evaluated during 1st, 7th and 14th days of refrigerated storage. Addition of β-glucan significantly (p ≤ 0.05) improved whey separation (syneresis), viscosity, texture profile and sensory characteristics during storage. The TPA characteristics such as hardness, cohesiveness and resilience of yoghurt samples improved significantly during storage with the incorporation of β-glucan whereas, β-glucan added yoghurt obtained higher consistency coefficient (K), thus, indicated a thicker and compact texture. Sensory analysis of stored yoghurt indicated that yoghurt samples in the present study containing even higher (1.5-2%) β-glucan level had obtained the higher average overall acceptability (8.1 to 8.3 on 9-point scale) score as compared to a low fat yoghurt containing lower β-glucan level (0.5%) reported in the literature.