The addition of buttermilk powder and transglutaminase improves textural and organoleptic properties of fat-free buffalo yogurt

Abstract

To meet the increased consumer demand for yogurt with reduced fat content, various efforts have been made to improve the quality of reduced-fat variants that still is regarded as having inferior quality. As an alternative, a yogurt was produced from buffalo skim milk with the addition of microbial transglutaminase (TG; 1 U.g−1 protein) and buttermilk powder (BMP; 1 and 2% “w/w”). For comparison, a fat-free variant without TG or BMP and a full-fat yogurt were studied. Monitoring the pH drop during incubation time revealed that TG did not interfere with the pH reduction, while BMP addition accelerated the decline in pH. TG treatment or BMP addition substantially improved the water holding capacity functionality of the yogurt gel. Electrophoretic analysis revealed that the addition of BMP enhanced the reactivity of TG as indicated by the appearance of high molecular weight protein polymer bands. These results were confirmed by scanning electron microscope analysis. The addition of TG and BMP, either individually or in combination, showed a marked impact on gel network, resulting in a more compact and dense gel structure accompanied by irregular agglomerated clusters of protein aggregates. Fat-free yogurts of individually BMP addition exhibited the most desirable organoleptic attributes as indicated by a sensory panel and were perceived as similar to the full-fat yogurt perception. Overall, the addition of TG or BMP appeared to have potential as a valuable alternative in fat-free yogurt production, and BMP can be used as a source of extra protein, which in turn offers promising option to develop innovative functional fat-free yogurt.