Abstract
Purpose
Smoothness plays a crucial role in yogurt's deliciousness. Fermenting yogurt at lower temperatures extends fermentation time but makes it smoother. However, the reason why this low-temperature fermentation leads to a smooth texture has yet to be fully understood. Therefore, this study created yogurts fermented at different temperatures to compare their sensory, physical, and structural characteristics.
Methods
Yogurts were produced using a milk base with the same composition and fermented at three different temperatures (33℃, 38℃, and 43℃). Sensory evaluation (CATA) examined the effect of fermentation temperature on the texture of yogurt. Physical properties that were measured included hardness and the storage modulus G' during fermentation. Structures of yogurt were analyzed by using CLSM and SEM as the main techniques.
Results
Sensory evaluation showed that yogurts fermented at three different temperatures fell into two groups: those fermented at 33℃ and those at 38℃ and 43℃. Yogurt fermented at 33℃ exhibited a soft and smooth texture. In physical properties, the strain rate brittleness was significantly higher for yogurts fermented at 33°C than those at 43°C. The onset of G' in dynamic viscoelasticity measurements during fermentation was approximately 110 minutes later for yogurts fermented at 33℃. Results from structural observations using CLSM and SEM showed that yogurts fermented at 43°C exhibited coarse structures, while those at 33°C exhibited dense structures. Along with other results, we analyze that yogurt fermented at low temperatures has a smooth texture.
