Production of Cereal- based Probiotic Beverage Optimized by Response Surface Methodology and Investigation of Its Properties

In general, most probiotic products are dairy-based and a few efforts have been made to develop probiotic products using other substrates such as cereal grains. Rice can be used as a basis for the production of many functional foods. However, rice in Iran is mostly consumed as plate food rather than in the formulation of relevant functional foods. In this study, the response surface methodology (RSM) was used to optimize the formulation of rice drink based on sensory and physico-chemical properties. This study was conducted in two phases. First, the optimal formula of beverage was determined based on the scores of the organoleptic characteristics (odor, color, taste, mouth feel and overall acceptance) and the measurement of pH and Brix. Independent variables in this study in 5 levels were rice extract (ranging from 30 to 70 ml), orange juice concentrate (ranging from 5 to 15 g), sesame extract, and pumpkin seed extract (both ranging from 0 to 15 ml). The results were investigated using the central composite design (CCD). In the second stage, the optimal formula for production of rice beverage was proposed. The probiotic bacteria, Lactobacillu acidophilus were inoculated in the beverage, and the viability of the bacteria was assessed during 21 days of storage at 4 °C. According to the results, the optimal values of independent variables in production of rice-based beverage were obtained to be 60 ml rice extract, 12.3 g orange concentrate, 11.3 ml pumpkin seed extract and 11.3 ml sesame extract. Investigation of bacterial survival showed that the number of probiotic bacteria at the end of the storage period was still over bid for provision of health effects (>106 cfu/ml). The results showed that such studies can accelerate the development of new and non-dairy functional products with unique nutritional properties.