بهينه سازي خواص فيزيكوشيميايي و حسي در بستني كم كالري

Optimization of physico-chemical and sensory properties in low calorie ice cream

Calorie content of ice cream can be decreased by substitution of its two main energy sources, fat and sugar. However, reducing sugar and fat content of ice cream may affect its physico-chemical characteristics and subsequently the quality of ice cream. The main objective of this research was to find the opotimal replacement ratio of fat and sugar in low calorie ice cream, keeping the quality at acceptable level. Fat and sugar of a reference ice cream with 8% fat and 15% sucrose were replaced with starch gel and glucose syrupe in three separate trials. In the first and second trials, glucose syrupe and starch gel were rep] aced separately at the ratios of 0, 25, 50. 75 and 100% for sucrose and fat. In the third trial, simultaneous replacement of fat and sucrose was carried out at the same ratio of the first two trials. Two levels of stabliser (0.2 and 0.3%) were used. In all trials, overrun, whipping rate, melting resistance, vicosity, density, pH, total solids and calorie content were determined and the results were analysed as a factorial experiment in compeletly randomised design with 3 replicates. Sensory properties of samples (taste, aroma, texture and total acceptance) were judged by 10 panelists. Glucose had no effect on physicochemical characteristics regardless the ratio of replacement. Therefore, its effects on sensory properties was only studied in the third trial. However, replacement of fat by starch gel at ratios higher than 50% resulted in a significant increase of viscosity (P<0.05) and a considerable decrease in overrun, total solids, melting resistance and whipping rate. Taste and total acceptance scores were significantly lower than reference ice cream at fat replacement ratios higher than 50%. The results of this research showed that starch gel at the ratios of 50% could be an appropriate cheap substitute for fat with a considerable reduction of calorie while maintainig phyico-chemical and sensory properties of ice cream.