The effect of guar gum as the fat substitute on some sensory and chemical properties of low-fat yogurt

Yogurt is one of the high consumption fermented products of milk which has a positive effect on health due to its high nutritional value. The consumption of low-fat yogurt causes cholesterol reduction; however, as the fat is lowered, the strength of yogurt texture is also decreased. In order to avoid this problem, hydrocolloids could be applied. In this research, the effect of using different concentrations (0.01, 0.05, 0.1, 0.25, 0.5%) of guar gum on some Sensory and Chemical properties of low-fat yogurt has been studied. All samples were produced in the same conditions in temperature of 4 ο C and were kept for 21 days. The tests for acidity, pH, free fatty acid, and diacetyl measurement were done on the samples every 7 days. According to the obtained results, during storage, the rate of acidity and free fatty acid had increased, but pH decreased. Increasing guar to 0.5% had reduced the yogurt quality in its color, taste and the panelists’ general view. Odor test in yogurt indicated that increasing guar to higher than 0.25% could cause unpleasant odor in the product. Also, the use of guar gum could cause the decrease of diacetyle production in the enriched samples as compared with the controlled samples