In a stride towards enhancing the quality of yoghurt products, researchers from University of Chemistry and Technology, Prague have uncovered exciting findings that shed light on the combined impact of microbial transglutaminase (MTG) treatment and exopolysaccharides (EPS) on the rheological and microstructural properties of yoghurt.
Confocal laser scanning microscopy images of yoghurt samples: A, yoghurt fermented by non-EPS-producing culture CCDM RX 22 without MTG addition; B, yoghurt fermented by non-EPS-producing culture CCDM RX 22 treated by 1 U g−1 of MTG simultaneously with culture; C, yoghurt fermented by a mixed EPS-producing culture of Streptococcus thermophilus CCDM 144 and Lactobacillus delbrueckii subsp. bulgaricus CCDM 767 without MTG addition; D, yoghurt fermented by a mixed EPS-producing culture of Streptococcus thermophilus CCDM 144 and Lactobacillus delbrueckii subsp. bulgaricus CCDM 767 treated by 1 U g−1 of MTG simultaneously with culture. Red structures and proteins stained with FastGreen dye. Dark areas represent empty pores.
In a study that promises to transform the texture and quality of yoghurt, researchers have explored the combined effects of microbial transglutaminase (MTG) treatment and exopolysaccharides (EPS) on the rheological and microstructural properties of this beloved dairy product. The results, published in the recent research article, shed light on an innovative approach to enhancing yoghurt's consistency, viscosity, and overall sensory experience.
The study delved into the intricate interplay between MTG, EPS, and the fermentation process in shaping yoghurt's properties. The researchers aimed to understand how these elements, when introduced at different stages of production, impact the final texture and structure of yoghurt.
“The experiment involved treating milk with transglutaminase both prior to fermentation and simultaneously with a yoghurt culture. Fermentations were conducted at two different temperature ranges: short-term fermentation at 42°C for 6-8 hours and long-term fermentation at 30°C for 16-18 hours.” stated Stepan Marhons, the corresponding author of the study. The team used two distinct yoghurt cultures—one that produces EPS and another that does not—to observe the contrasting effects of EPS presence.
The findings of the study revealed remarkable transformations in the yoghurt's properties. Treatment with transglutaminase alone led to an increase in gel strength and viscosity. However, the most notable effects were observed when MTG and the yoghurt culture were applied simultaneously. This dual approach resulted in a more substantial enhancement of these textural attributes.
Exopolysaccharides, naturally occurring polymers secreted by microorganisms, further elevated the positive impact of MTG. These substances played a pivotal role in augmenting gel strength and viscosity, setting the stage for a remarkably improved sensory experience for consumers.
One of the most intriguing outcomes of the research was the alteration in protein structures within the yoghurt matrix. The introduction of MTG and EPS contributed to the development of new three-dimensional protein structures. These reconfigured structures led to a reduction in the size of pores between protein chains, significantly enhancing the yoghurt's ability to retain water. Consequently, the unwanted phenomenon of syneresis—whey separation—was curtailed, ensuring a smoother, more consistent product.
Furthermore, the ropiness that is sometimes observed in yoghurts rich in EPS was considerably minimized through MTG treatment. This breakthrough contributed to an enhanced acceptability of the yoghurt's texture, making it more palatable and enjoyable for consumers.
The implications of this research are immense, as it paves the way for a revolution in yoghurt production techniques. The combination of microbial transglutaminase and exopolysaccharides holds the potential to create yoghurts with superior texture, improved water-binding properties, and reduced syneresis. This not only satisfies consumer preferences but also has the potential to extend the shelf life of the product.
As the food industry continues to evolve, this study stands as a testament to the power of scientific innovation in redefining everyday products. The findings offer both consumers and manufacturers an exciting glimpse into the future possibilities of yoghurt production, where texture and quality reach new heights.
In summary, the research underscores the transformative influence of microbial transglutaminase and exopolysaccharides on yoghurt's rheological and microstructural properties. This study provides a remarkable avenue for revolutionizing the yoghurt industry, offering consumers a tantalizing taste of what's to come.
Text is based on the research article:
Marhons, Š., Hyršlová, I., Stetsenko, V., Jablonská, E., Veselý, M., Míchová, H., … & Štĕtina, J. (2023). Properties of yoghurt treated with microbial transglutaminase and exopolysaccharides. International Dairy Journal, 144, 105701.