The effect of rice flour on survival of Lactobacillus paracasei in fruit yoghurt and its qualitative properties with response surface methodology
Subject Areas : Aquatic ProductsFarnaz Nabizadeh 1 , Paniz Zinsaz 2
1 - Department of Food Science. Faculty of Agriculture. Mahabad Branch Islamic Azad University. Mahabad. Iran.
2 - Graduated of Master of Food Science and Industry Engineering. Faculty of Agriculture. Mahabad Branch Islamic Azad University. Mahabad. Iran.
Keywords: response surface methodology, Fruit yogurt, Lactobacillus paracasei bacterium, Rice flour,
Abstract :
In this study the effect of rice flour on survival of lactobacillus paracasei and qualitative properties of fruit yogurt was investigated during storage, using response surface method (RSM). For this, rice flour in three ranges of (0, 1.5 and 3%) was added to the milk. Then the milk and was pasteurized in 85ºC for 15 minutes. After cooling, yoghurt starter culture and probiotic bacterium inoculated in 43 ºC and added into sterile containers containing 15% peach puree. The samples were incubated in 42 ºC until reaching pH 4.6 ±0.1. Then the samples were cooled down to 4 ºC and refrigerated in the same temperature until experiment day. Survival of lactobacillus paracasei, pH, amount of moisture, acidity, syneresis and apparent viscosity and sensory properties were investigated in three periods of (1, 11 and 21 days). The statistical analysis of the results showed that with increasing of rice flour, lactobacillus paracasei count increased and decreased during storage (p
_||_