Abstract:

For better development of the carrot industry, carrot rich in various nutriments was used as fermentation substrate to product yoghurt by the fermentation of a mixed starter composed of immobilized Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp bulgaricus. The present study focused on developing a novel optimal process for carrot yoghurt production. Based on one-factor-at-a-time investigations, orthogonal array designs were employed to optimize fermentation medium composition and fermentation conditions. The optimal fermentation medium composition was found to be consist of milk powder 9 g, carrot 13 g, white sugar 8 g and distilled water 100 mL, and the optimal mixing ratio for immobilized Streptococcus salivarius subsp thermophilus and Lactobacillus delbrueckii subsp bulgaricus was 2:1 for the fermentation at 37 ℃ for 7 h using an inoculum size of 6% followed by cold storage at 4 ℃ for 12 h. The product obtained under the above optimal conditions was rich in various nutrients and had a pleasant mouth feel.

Key words: immobilized Streptococcus salivarius subsp thermophilus, immobilized Lactobacillus delbrueckii subsp bulgaricus, carrot yoghurt formula, fermentation technology