Effect of Storage of Therapeutic Product on LAB Bacterial Counts and Acidity

Abstract

This investigation carried out to utilize whey and rice in preparation of a therapeutic product. The raw materials were mixed at a ratio of 1:10 rice to whey (w/w). Five treatments were prepared by fermentation with either Lb. acidophilus and Lb. casei, or mixes of both. The treatments were: T1 (Lb. acidophilus), T2 (Lb. casei), T3, T4, T5 which were mixes of (Lb. acidophilus+Lb. casei) starters with ratios of 1:1, 1:2, 2:1, respectively. The best fermentation period was two days as highest therapeutic bacterial counts resulted. The treatments were divided into two groups; first group stored at -18°C for four months, the second group dried at 45°C, then stored at 25°C for three months. The frozen treatments revealed significant differences (p<0.05) in titrable acidity which were 0.43-0.85% for T2, T3, respectively. The pH values were (3.63-4.72) for T4, T2, respectively. LAB counts dropped for all treatments during frozen storage. The drop was between 19.14-60.05% for T1 and T4, respectively. The titrable acidity for dried treatments was 0.33-0.66% for T2, T1, respectively. Then increased to 0.46-0.75% after three months of storage for T2, T5, respectively. Highest pH value of 4.5 obtained for T2. There was a slight drop in pH value for all treatments after 3 months of storage. LAB counts dropped for all treatments after drying. The highest number of 5.48 × 10¹⁰ cfu/gm was for T4. LAB counts were acceptable to impart therapeutic character to the product.