Optimization of fermentation process and quality analysis of melon yogurt

Abstract

Melon yoghurt was prepared using pure milk and melon juice as main raw materials. Using acidity, water holding capacity and sensory score as investigation indicators, on the basis of single factor experiments, the process parameter of melon yoghurt was optimized by response surface methodology. In addition, the storage characteristics, antioxidant activities, rheological properties, microstructure and volatile flavor of the optimized melon yogurt were studied. Results showed that the optimal process parameters of melon yogurt were as follows: melon juice addition 7%, erythrose addition 7%, fermentation time 8 h, and inoculum 0.3%. Under the optimal process, the acidity of melon yogurt was 82.6 °T, the water holding capacity was 81.13%, and the sensory score was 90.70. After 21 d of storage, the sensory scores, acidity, water holding capacity of melon yogurt were 73.0, 88.4 °T, 68.2%, respectively. The optimized melon yogurt had a more uniform, continuous, compact protein network structure and better rheological properties. A total of 33 volatile compounds were detected, including 7 alcohols (19.64%), 9 esters (28.43%), 7 aldehydes (27.70%), 4 ketones (11.69%), 2 acids (9.18%), and 4 other compounds (3.36%). The addition of melon juice could improve the quality of yogurt and gave yogurt with melon aroma.

Keywords

• melon yogurt|fermentation process optimization|storage property|volatile flavor components