optimization of low fat probiotic yogurt production using combined design

heart disease - cardiovascular, cancer and obesity are the main causes of death and there are direct relationship between the consumption of high-fat foods and the incidence of these diseases. therefore the demand for low-fat food products and probiotics has been dramatically increased. in this study, the effect of different levels of three hydrocolloids (inulin, chitosan and xanthan) at three levels (1, 2 and 3%) on survival of lactobacillus acidophilus, physicochemical and sensory properties of yogurt during 15 days of storage was explored using a combined design. increased levels of inulin and chitosan positively affected la-5 count, apparent viscosity, acidity and sensory scores during storage. using graphical method of optimizing (overlaid contour plots), optimum ratios were: inulin 93.4%, xanthan 0.6% and chitosan 6%.