Yeast whey-enriched bread: nutritional profile and potential functional relevance

Abstract

Background: Microorganisms are an innovative biotechnological option for creating new yeast whey-enriched bread. Products obtained with the help of microorganisms can have a beneficial effect on human health and be successfully used in the food industry, as well as in the nutraceutical and pharmaceutical fields. The biotechnological potential of yeast and lactic acid bacteria is confirmed by their wide application in the fermentation of food products. At the same time, autochthonous strains in different matrices often demonstrate higher functional and technological indicators, which justify the microbiological perspective of their potential use in obtaining yeast whey-enriched bread. In this regard, it is of interest to study the potential of autochthonous cultures of yeast and lactic acid bacteria of ttkhmor - bread sourdough used in Armenia since ancient times.

Objective: The study aims to isolate indigenous yeasts from ttkhmor and explore their potential for developing prototype of enriched bread for health.

Novelty: This work advances prototype of enriched bread development by leveraging a two-stage co-cultivation of indigenous yeast and lactic acid bacteria in whey, yielding high yeast biomass and improving shelf life and spoilage resistance versus commercial yeast controls—while maintaining comparable physicochemical quality. The approach links sustainable whey valorization with measurable technological and nutritional benefits.

Methods: Samples of ttkhmor and handicraft production dough were collected from rural areas of Armenia. Yeast α-glucosidase activity was determined in Yeletsky gasometric device. The nutritional value of bakery products was researched by analyzing the amino acid composition of yeast strain proteins. The quality indicators of bread were studied by physicochemical parameters. Sensory assessment of bread quality was carried out by closed tasting of the samples under study.

Results: More than 150 ttkhmor samples were collected from different geographical zones of Armenia. A total of 498 yeast isolates and 338 LAB isolates were obtained from the ttkhmor samples. Seven representative strains selected from the yeasts with high fermentation activity were subjected to species identification by sequencing. The yeast strain Saccharomyces cerevisiae Sevan-60 (deposited in Microbial Depository Center under the number MDC-9792) isolated from the ttkhmor of Tsaghkunk village, Sevan region (mountain zone) was selected based on its antimicrobial activity against Bacillus subtilis and biochemical characteristics. The biological value of the yeast biomass of strain Sevan-60 is characterized by a high content of essential and aromatic amino acids. The parameters used for strain evaluation were
related to enzymatic activity and utilization of lactic acid as the sole carbon source.

Conclusion: Taken together, the above studies indicate the potential of using ttkhmor microorganisms in creating yeast whey-enriched bread. A method has been developed for two-stage co-cultivation of lactic acid bacteria and the indigenous S. cerevisiae Sevan-60 strain to obtain fermented whey with a high yeast biomass yield of 47 g/l for use in baking. Bread quality assessment showed that bread baked using fermented whey, with comparable physicochemical parameters (volume yield and porosity), was superior to the control bread prepared with commercial industrial yeast in terms of spoilage resistance and longer shelf life. At the same time, the experimental yeast whey-enriched bread combines all the useful components of a functional product characteristic of the combined use of yeast, LAB, and whey, in particular, high functional indicators of yeast protein as well as whey protein.

Keywords: Ttkhmor, yeast, LAB, whey proteins, baking, prototype of enriched bread, human health.