Impact of new ingredients obtained from brewer's spent yeast on bread characteristics

Quality and staling characteristics of white bread fortified with lysozyme-hydrolyzed mealworm powder (Tenebrio molitor L.)

Edible insects have a low environmental impact but are rich in nutrients and have been promoted as alternative protein sources. However, adding insect flour to bread negatively affects the overall quality, especially loaf volume and textural properties. Furthermore, relevant studies on chitin are limited. Therefore, this study examined chitin hydrolysis using lysozymes to enhance the quality characteristics in defatted mealworm (Tenebrio molitor L.) powder (DF-M)-supplemented bread. The chitin hydrolysis degree by lysozymes was evaluated using the 3,5-dinitrosalicylic acid assay and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The amount of chitin oligomers increased with time, and no significant difference in the hydrolysis efficiency between water and 400 mM acetate buffer was observed. Enzymatic hydrolysis improved the DF-M water- and oil-binding and antioxidant capacities. In addition, chitin hydrolysis increased the volume and softened the texture of white bread. In particular, bread supplemented with DF-M hydrolyzed for 4 h at 10 % had the highest moisture content among the mealworm-added bread groups during storage for 5 days. Moreover, sensory evaluation showed a positive effect of chitin hydrolysis on acceptability. Our findings indicate that chitin hydrolysis can improve the quality of bread containing insect additives. In conclusion, this study provides novel insights into producing high-quality and functional bakery products from edible insects by the enzymatic hydrolysis of edible insect powders and could expand the applications of edible insects as food ingredients.

Valorization of Spent Brewer’s Yeast for the Production of High-Value Products, Materials, and Biofuels and Environmental Application

Spent brewer’s yeast (SBY) is a byproduct of the brewing industry traditionally used as a feed additive, although it could have much broader applications. In this paper, a comprehensive review of valorization of SBY for the production of high-value products, new materials, and biofuels, as well as environmental application, is presented. An economic perspective is given by mirroring marketing of conventional SBY with innovative high-value products. Cascading utilization of fine chemicals, biofuels, and nutrients such as proteins, carbohydrates, and lipids released by various SBY treatments has been proposed as a means to maximize the sustainable and circular economy.

Valorisation of brewer's spent grain flour (BSGF) through wheat-maize-BSGF composite flour bread: optimization using D-optimal mixture design

Inclusion of brewer's spent grain flour (BSGF) in food formulations has been reported to have nutritional and health benefits due to the contents like, protein, fibre and phenolic compounds. Bread has been used as common vehicle for functional and nutritive ingredients due to its wide consumption. Several studies attempted to incorporate BSGF flour in baked products. Studies also have reported on the application of maize flour in bread and baked products. However, there is limited information on the possibility of producing bread from composite flour using BSGF with other widely consumed cereals like maize together with wheat flour. The study investigated the optimization of bread recipe made from wheat flour, maize flour and BSGF in order to attain optimal physicochemical and sensory attributes using D-optimal mixture design. A total of 16 runs were formulated using design expert software. The blend proportions of wheat, maize and BSGF had a significant (p < 0.05) influence on bread specific volume, volume and density. Increase in BSGF proportion decreased the specific volume and volume whereas the loaf density increased. The specific volume increased with increase in wheat flour proportion. The combination of high levels of BSGF and maize, however, brought about a slight increase in specific volume compared to combinations of low levels of BSGF and maize flour. The fibre, protein and ash content of bread significantly (p < 0.05) increased with increase in BSGF and maize proportion whereas the effect of maize flour was less pronounced compared to BSGF. The sensory attributes including colour, taste, flavour, texture and overall acceptability were significantly (p < 0.05) reduced with increase in BSGF and maize flour content. Using the optimization criteria where all sensory attributes have to be at least “like slightly” intensity, maximized, specific volume, fiber and protein, that the best results were found between 73 to 87% of wheat, 9–20% maize, and 0–11% BSGF based on graphical optimization. Numerical optimization indicated that best results were using combination of 65% wheat, 20% maize flour, and 15% BSGF with a desirability value of 0.524. According to the results of the study, BSGF can be incorporated up 10% and maize flour up to 20% obtain an acceptable product.

The synthesis of soluble and volatile bioactive compounds by selected brewer's yeasts: Antagonistic effect against enteropathogenic bacteria and food spoiler - toxigenic Aspergillus sp

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Brewing fermentation residue possesses bacteriostatic and fungicidal activity.

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Crude brewing fermentation residue is an antimicrobial agent.

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Brewer’s yeasts secrete soluble and volatile bioactive compounds.

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Ethanol and 2,3-butanediol possess bacteriostatic and antifungal properties.

Contamination by Aspergillus sp. and the accumulation of its mycotoxins in food and beverages have a high impact on human health and food safety. This investigation inquires the ability of brewer’s yeasts discarded after fermentation (brewing fermentation residue, BFR) to synthesize bioactive compounds and to biocontrol Aspergillus sp. BFRs of Saccharomyces cerevisiae MBELGA62 and Pichia kudriavzevii MBELGA61 proved to have bacteriostatic properties and to be efficient in fungal growth reduction, decreasing the growth rate of Aspergillus flavus and Aspergillus parasiticus up to 37.8% and 42.5%, respectively. Fungal mycelium degradation along with absentia of conidia was detected near the yeast inoculum. Moreover, the yeasts synthesize volatile bioactive compounds that extend Aspergillus sp. lag phase above 100% and decrease fungal growth rates from 20% towards 44%, along with the complete inhibition of conidia synthesis. These results indicate the potential of this residue to be used in biocontrol applications in the food industry.

Biotechnological Addition of β-Glucans from Cereals, Mushrooms and Yeasts in Foods and Animal Feed

Varied cereal plants including, mushrooms, yeast, bacteria and algae are important sources of β-glucans, and many extraction procedures have been used in order to recover these valuable naturally occurring polysaccharides. The rheological and molecular properties of β-glucans can be utilized to be incorporated into various foods and to offer properties extremely beneficial to human health. Their functional effects are mainly determined by their molecular and structural characteristics. Consumption of foods fortified and enriched with β-glucans can contribute to the treatment of certain chronic diseases. Reduced cholesterol, cardiovascular and diabetic risk and moderate glycemic response of foods have been recorded with the consumption of these biologically active compounds. In addition, β-glucans are characterized by anti-cancer, antioxidant, anti-inflammatory and antiviral activities. As β-glucans interact with the foods in which they are incorporated, this review aims to discuss recent applications with quality and nutritional results of β-glucans incorporation with foods such as beverages, dairy, bakery, meat and pasta products, as well as their addition in animal feeds and their uses in other fields such as medicine.

Spent Brewer's Yeast as a Source of Insoluble β-Glucans

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer’s yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer’s yeast, and even less for spent brewer’s yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer’s yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

Brewer’s Spent Yeast (BSY), an Underutilized Brewing By-Product

The repurposing of by-products and the reduction of waste from food processing streams is an ever-increasing area of interest. Brewer’s spent yeast (BSY) is a prevalent by-product of the brewing industry. The spent yeast cells are removed at the end of the bulk fermentation. A small amount of it is used to start the next batch of fermentation; however, the majority of the spent yeast is discarded. This discarded yeast is high in nutrients, in particular proteins, vitamins and minerals, as well as containing functional and biologically active compounds such as polyphenols, antioxidants, β-glucans and mannoproteins. At present, BSY is mainly used in animal feed as a cheap and readily available source of protein. This review explores alternative, value-added applications for brewer’s spent yeast including nutritional ingredients, functional food additives as well as non-food applications. A major challenge in the utilization of BSY in food for human consumption is the high level of RNA. An excess of RNA in the diet can lead to an increase in uric acid in the bloodstream, potentially causing painful health conditions like gout. This issue can be overcome by RNA degradation and removal via additional treatment, namely heat treatment and enzymatic treatment. There is potential for the use of BSY ingredients in various food applications, including meat substitutes, bakery products and savory snacks.