The quality characteristics of probiotic yogurts enriched with carob flour: ultrasonication effects at different production stages.

Abstract

The health benefits, nutritional value and also the quality of foods are important aspects for the health-conscious consumers. In this study, the effects of ultrasound treatment at different stages of production (before inoculation (group B), both before and after inoculation (group C), and after inoculation (group D)) on some physicochemical, rheological, microbiological, and sensory properties of probiotic yogurts enriched with carob flour (CF) were investigated. Ultrasound treatment shortened the fermentation time for groups C and D, but did not significantly change the total solids, fat, and protein contents of probiotic yogurts enriched with CF. However, ultrasound-treated groups had higher pH and lower lactic acid values. Ultrasound treatment also improved the counts of yogurt bacteria and probiotic bacteria compared to the untreated control group. In addition, ultrasound-treated groups B and C had higher hardness, viscosity, and water holding capacity (WHC) values, while group D had similar values with the control. Enrichment with CF increased the red and yellow color ratios, and the ultrasound-treated groups (B and C) had higher a* (redness) values and lower b* (yellowness) values. The overall acceptability scores of ultrasound-treated groups were higher, and the texture scores of groups B and C were also higher.