A Comprehensive Study of the Impacts of Oat β-Glucan and Bacterial Curdlan on the Activity of Commercial Starter Culture in Yogurt

Abstract

This study provides important information about the impacts of various levels of oat (OBG) and bacterial (curdlan) β-glucan and fat contents in milk on survivability and metabolism of yogurt starter cultures. The results show that addition of β-glucans in the concentration higher than 0.25% reduced starter bacterial counts during storage and prolonged the milk acidification process. A significant increase in lactose consumption by starter cultures was noted in the yogurt samples with OBG addition up to 0.75%. The highest (by 567% on average) increase in lactic acid content was noted in the control yogurts. Whereas the lowest (by 351%) increase in lactic acid content was noted in yogurts with OBG. After 28-day storage, the acetic aldehyde content was significantly influenced by fat content, type and addition level of polysaccharide. A higher increase in acetoin content was noted in samples with 0.25% than in samples with 1% of polysaccharides. In turn, significantly lower increases in diacetyl and 2,3-pentanedione contents were observed in the yogurt samples with OBG than in these with curdlan, with diacetyl production increase along with the higher concentration of the polysaccharide. The addition of OBG and curdlan to milk contributed to differences in the starter culture metabolism, consequently, in the milk acidification dynamics.

Effects of Oat β-Glucan on the Textural and Sensory Properties of Low-Fat Set Type Pea Protein Yogurt

“…This phenomenon might be due to the ability of β-glucan to interact with the protein, thus preventing excessive protein aggregation in a gel, phase separation and the formation of a denser structure. Additionally, β-glucan had high water absorption and thus free water could fill the gel structure, forming a strong three-dimensional structure [ 31 ]. Similarly, curdlan gum with a triple helix structure was able to interact with protein molecules, thus strengthening the gel structure [ 32 ].…”

β-Glucan as a Techno-Functional Ingredient in Dairy and Milk-Based Products—A Review

“…Xiaoqing Qu et al [ 69 ] claim that a dose of oat β-glucan at the level of 0.3% somewhat changes the chemical structure of three-dimensional mesh structure of yogurt due to the fact that oat β-glucan slows down the interaction with casein, which shortens the fermentation process by 16 min and increases the taste properties of the product. At the same time, a study by other scientists indicates that oat β-glucan in the amount of 1.4% does not provide proper structuring of yogurt and leads to a liquid consistency of the product [ 94 ], which can be explained by a specific combination of lactic acid cultures [ 84 ], a reduced fermentation temperature (36 °C), and an increased dose of polysaccharide, which was due to the desire to position the product as functional in terms of its dietary fiber content, but without a scientific explanation of the product formulation, it is impossible. Thus, the addition of oat β-glucan to milk before fermentation slows protein aggregation due to phase separation between milk proteins and β-glucan, which leads to a decrease in gelation [ 96 ].…”

“…As in the case of cereal β-glucan use, β-glucan of bacterial origin also leads to an increase in the resistance of ice cream to melting, which is probably related to the formation of a stable polysaccharide matrix, inside which molecules retain free moisture. However, Marek Aljewicz et al [ 84 ] reported that a dose of β-glucan isolated from Agrobacterium sp. at a level of 1% provides the same resistance to melting value as 0.5% highly purified oat β-glucan, which suggests a less pronounced ability of bacterial β-glucan to retain free moisture.…”

Utilization of Prickly Pear Peels As Antioxidants, Dietary Fiber and Functional Ingredients for Production of A Healthy Yoghurt Drink

“…These results were in line with Hamdy et al(2021). The development of diacetyl and acetaldehyde levels was due to the metabolic activity of starter cultures in the presence of PPP (Aljewicz et al, 2020). Sensory evaluation of yogurt drink samples.…”