Development of Value Added Stirred Yoghurt Rippled with Cooking Chocolate Syrup

Abstract

Developing a yoghurt incorporating cooking chocolate syrup is attempted with an aim of adding value to conventional yoghurt by increasing the organoleptic profile of the product. The composition of the conventional stirred yoghurts were modified slightly by varying gelatin percentages as 0.5%(w/w), 1.0%(w/w) and 1.5% (w/w). Best gelatin percentage was selected by sensory evaluation using 07 trained panelists. Stirred yoghurts prepared with selected gelatin percentage were rippled with 6.5 ml of chocolate syrup of three concentrations, 40%, 50% and 60% (percentage by weight). Chocolate incorporated stirred yoghurts were evaluated by using 30 untrained panelists with 5 point hedonic scale to assess sensory attributes such as, colour, appearance, chocolate flavour, sweetness and overall acceptability. Sensory data were analyzed by friedman non-parametric statistical method while titratable acidity and pH were analyzed by one-sample t-test in MINITAB 14. Shelf life determination was done by analyzing titratable acidity, pH, yeasts and moulds, total colony count (TCC), coliforms and Escherichia coil at two days intervals for 15 days comparing with the plain stirred yoghurt which was chosen as the control. Stirred yoghurt prepared with 50% chocolate syrup concentration showed higher (P<0.05) preference with all sensory attributes except appearance. The pH and titratable acidity of the above concentration was significantly higher (P<0.05) compared to the control at day 3. Coliforms, Escherichia coil and Yeast and mould counts were in compliance with specifications in Sri Lankan Standards for the set yoghurt during 10 days of refrigerated storage. Based on the results it can be concluded that stirred yoghurt rippled with chocolate syrup prepared with 0.5% gelatin and 50% chocolate syrup concentration has the highest sensory attributes with 09 days of shelf life at 4 °C temperature. Key Words; Stirred yoghurt, Gelatin, Chocolate Syrup