Physicochemical, rheological, and microbiological properties of lactose‐free functional yogurt supplemented with fructooligosaccharides

Abstract

This study aims to explore the impact of fructooligosaccharides (FOS) on physicochemical, rheological, and microbiological properties of lactose‐free functional yogurts fermented with probiotic cultures. Milk was hydrolyzed by addition of β‐galactosidase and supplemented with FOS at 3% (wt/wt). Lactose hydrolysis and FOS supplementation increased acidification rate during fermentation of yogurts. FOS helped to improve syneresis but resulted in weaker gel network. Viability of lactic acid bacteria increased when FOS was added. The results suggest that it is possible to obtain a lactose‐free yogurt with functional properties contributing in improved nutritional characteristics suitable for people with lactose intolerance. Practical applications Lactose intolerance affects more than 75% of world population. This lactase deficiency condition limits people from consuming healthy dairy products. Although yogurts are known to have reduced lactose content, their lactose content, in fact, is still high. Manufacturing of low lactose and lactose‐free milk has been developed. However, the variety of products is limited. In this present study, development of lactose‐free yogurts enhanced with fructooligosaccharides as prebiotics was studied. Physicochemical, rheological, and microbiological characteristics of yogurts were evaluated. We believe that dairy product manufacturers can benefit from our findings and utilize our approach to create a new functional product for people with lactose intolerance.

The roles of brewers’ spent grain derivatives in coconut-based yogurt-alternatives: Microstructural characteristic and the evaluation of physico-chemical properties during the storage

“…5 b). The same phenomenon has been reported previously with the addition of tapioca starch in WSCE-based yogurt-alternatives ( Pachekrepapol et al, 2021b ). However, the derivation in the syneresis value in this study is more intense.…”

“…Furthermore, the evolution in shear stress during the storage could explain its ability in gel forming as well as in preserving the consistency during the storage period. Initially, after the fermentation process was ended, the formed bond between casein micelles of the milk and amino acids from BSG could be weaker ( Pachekrepapol et al, 2021b ) and after refrigerated storage occurred due to the hydration of macromolecules and stabilization ability of the added ingredients ( Ramírez-Sucre & Vélez-Ruiz, 2013 ) such as BSG derivatives in this study.

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“…While BSGF contains protein 20–30% ( Naibaho et al, 2021 ; Naibaho & Korzeniowska, 2021a ) and it contains high amounts of dietary fiber (up to 55%) which was reported for its ability to disrupt network formation in food matrices ( Naibaho & Korzeniowska, 2021b ). BSG has a high ability in binding water ( Naibaho et al, 2021 ; Naibaho & Korzeniowska, 2021a ) which could diminish the protein mobility in the yogurt matrix ( Pachekrepapol et al, 2021b ). Consequently, it reduces the homogeneity and porosity of formed matrices and protein networks as observed in this study ( Fig.…”

“…BSGPs had a longer fermentation time compared to that in control and BSGF. A shorter fermentation time could reduce the protein network thus leading to the irregularity of the formed network ( Pachekrepapol et al, 2021b ). Furthermore, it also could reduce the amount of fat and protein in yogurt ( Sinamo et al, 2020 ).…”

“…This phenomenon might be due to a weaker gel formed on the first day of storage and it increased during the storage as mentioned previously. It was identified that formed gel could be weaker because of incomplete network ( Pachekrepapol et al, 2021b ) and hydration of macromolecules occurred during the storage which led to the formation of a stronger binding within the matrices ( Ramírez-Sucre & Vélez-Ruiz, 2013 ). Yogurt control and BSGF-added had a shorter fermentation time and at the same time had a lower syneresis value.…”