Emerging techno-functional capabilities of non-Saccharomyces yeasts as starter cultures in bread-making; a promising approach to develop clean-label bakery products

Introduction. Bread and bakery products contain nutritional components that make an integral part of human diet. Starter cultures are a promising way to prepare bakery products. The research objective was to study the effect of non-traditional flours and their wheat mixes on the activity, sensory, and physicochemical properties of starter cultures.
 Study objects and methods. The research featured Lesaffre starter cultures (Saf-Levain LV1 and Saf-Levain LV4) with lentil flour and green buckwheat flour. It involved organoleptic, titrimetric, and photocolorimetric methods, as well as the “ball surfacing” method, to determine the fermentation activity of starter cultures and to assess the changes in their volume. The acid content of the flour was determined by titrating the aqueous solution of the sample. The amount of reducing sugars was determined by the photocolorimetric method based on the interaction of carbonyl groups of sugars in an alkaline medium with copper glycerate; the optical density of the resulting solution was performed using a photoelectrocolorimeter. The change in the volume of the starter cultures was determined by a non-standard method of using measuring cups in the process of thermostating. The research also included a sensory evaluation of the semi-finished products.
 Results and discussion. Green buckwheat flour had a positive effect on the activity of starter cultures based on Saf-Levain LV4 and LV1. The sensory properties of starter cultures with non-traditional flours differed from the control samples in aroma, taste, appearance, and inflation rate. The acidity of the samples varied depending on the flour, its quantity, and the starting culture. The greatest accumulation of acids occurred in the sample with 50% of green buckwheat flour and the samples with 25 and 50% of lentil flour. The most intense reduction in the amount of reducing sugars was observed in the samples with 25 and 50% of green buckwheat flour (from 1.9 to 3.9 times, depending on the sample). In the samples with lentil flour, it was 75 and 100% (from 2.7 to 7.5 times, depending on the sample). The difference in the samples with LV1 was greater than in the samples with LV4, which can be explained by the differences in their microbial composition. The inflation rate was higher in the test samples than in the control.
 Conclusion. The resulting starter cultures can be recommended for baking industry and further research. Starter cultures based on non-traditional flours will eventually reduce the fermentation time and produce bakery products with high consumer properties. The non-traditional flours can expand the range of bakery products and increase their nutritional value.

In oenology, the utilization of mixed starter cultures composed by Saccharomyces and non-Saccharomyces yeasts is an approach of growing importance for winemakers in order to enhance sensory quality and complexity of the final product without compromising the general quality and safety of the oenological products. In fact, several non-Saccharomyces yeasts are already commercialized as oenological starter cultures to be used in combination with Saccharomyces cerevisiae, while several others are the subject of various studies to evaluate their application. Our aim, in this study was to assess, for the first time, the oenological potential of H. uvarum in mixed cultures (co-inoculation) and sequential inoculation with S. cerevisiae for industrial wine production. Three previously characterized H. uvarum strains were separately used as multi-starter together with an autochthonous S. cerevisiae starter culture in lab-scale micro-vinification trials. On the basis of microbial development, fermentation kinetics and secondary compounds formation, the strain H. uvarum ITEM8795 was further selected and it was co- and sequentially inoculated, jointly with the S. cerevisiae starter, in a pilot scale wine production. The fermentation course and the quality of final product indicated that the co-inoculation was the better performing modality of inoculum. The above results were finally validated by performing an industrial scale vinification The mixed starter was able to successfully dominate the different stages of the fermentation process and the H. uvarum strain ITEM8795 contributed to increasing the wine organoleptic quality and to simultaneously reduce the volatile acidity. At the best of our knowledge, the present report is the first study regarding the utilization of a selected H. uvarum strain in multi-starter inoculation with S. cerevisiae for the industrial production of a wine. In addition, we demonstrated, at an industrial scale, the importance of non-Saccharomyces in the design of tailored starter cultures for typical wines.

Mixed fermentations using controlled inoculation of Saccharomyces cerevisiae starter cultures and non-Saccharomyces yeasts represent a feasible way towards improving the complexity and enhancing the particular and specific characteristics of wines. The profusion of selected starter cultures has allowed the more widespread use of inoculated fermentations, with consequent improvements to the control of the fermentation process, and the use of new biotechnological processes in winemaking. Over the last few years, as a consequence of the re-evaluation of the role of non-Saccharomyces yeasts in winemaking, there have been several studies that have evaluated the use of controlled mixed fermentations using Saccharomyces and different non-Saccharomyces yeast species from the wine environment. The combined use of different species often results in unpredictable compounds and/or different levels of fermentation products being produced, which can affect both the chemical and the aromatic composition of wines. Moreover, possible synergistic interactions between different yeasts might provide a tool for the implementation of new fermentation technologies. Thus, knowledge of the Saccharomyces and non-Saccharomyces wine yeast interactions during wine fermentation needs to be improved. To reach this goal, further investigations into the genetic and physiological background of such non-Saccharomyces wine yeasts are needed, so as to apply '-omics' approaches to mixed culture fermentations.

Among the innovative trends in the wine sector, the continuous exploration of enological properties associated with wine microbial resources represents a cornerstone driver of quality improvement. Since the advent of starter cultures technology, the attention has been focused on intraspecific biodiversity within the primary species responsible for alcoholic fermentation (Saccharomyces cerevisiae) and, subsequently, for the so-called ‘malolactic fermentation’ (Oenococcus oeni). However, in the last decade, a relevant number of studies proposed the enological exploitation of an increasing number of species (e.g., non-Saccharomyces yeasts) associated with spontaneous fermentation in wine. These new species/strains may provide technological solutions to specific problems and/or improve sensory characteristics, such as complexity, mouth-feel and flavors. This review offers an overview of the available information on the enological/protechnological significance of microbial resources associated with winemaking, summarizing the opportunities and the benefits associated with the enological exploitation of this microbial potential. We discuss proposed solutions to improve quality and safety of wines (e.g., alternative starter cultures, multistrains starter cultures) and future perspectives.

Evaluation of indigenous non-Saccharomyces yeasts isolated from a South Australian vineyard for their potential as wine starter cultures

Yeasts play an important role in spontaneous fermentation of traditional alcoholic beverages. Our previous study revealed that a mixed-consortia of both Saccharomyces and non-Saccharomyces yeasts were responsible for fermentation of khadi, a popular, non-standardized traditional beverage with an immense potential for commercialization in Botswana. Functional characterization of isolated fermenting yeasts from mixed consortia is an indispensable step towards the selection of potential starter cultures for commercialization of khadi. In this study, we report the characterization of 13 khadi isolates for the presence of brewing-relevant phenotypes such as their fermentative capacity, ability to utilize a range of carbon sources and their ability to withstand brewing-associated stresses, as a principal step towards selection of starter cultures. Khadi isolates such as Saccharomyces cerevisiae, Saccharomycodes ludwigii and Candida ethanolica showed good brewing credentials but Lachancea fermentati emerged as the isolate with the best brewing attributes with a potential as a starter culture. However, we were then prompted to investigate the potential of L. fermentati to influence the fruity aromatic flavor, characteristic of khadi. The aroma components of 18 khadi samples were extracted using headspace solid phase micro-extraction (HSSPME) and identified using a GC-MS. We detected esters as the majority of volatile compounds in khadi, typical of the aromatic signature of both khadi and L. fermentati associated fermentations. This work shows that L. fermentati has potential for commercial production of khadi.

Higher salt intake is associated with the risk of cardiovascular and kidney diseases, hypertension and gastric cancer. Salt intake reduction represents an effective way to improve people’s health, either by the right choice of food or by a reduction of added salt. Salt substitutes are often used and also herb homogenates are treated by high pressure technology. Salt reduction significantly influences the shelf life, texture, pH, taste, and aroma of cheese. The composition of emulsifying salts or starter cultures must be modified to enact changes in microbial diversity, protease activity and the ripening process. The texture becomes softer and aroma atypical. In bakery products, a salt reduction of only 20–30% is acceptable. Water absorption, dough development, length and intensity of kneading and stability of dough are changed. Gluten development and its viscoelastic properties are affected. The salt reduction promotes yeast growth and CO2 production. Specific volume and crust colour intensity decreased, and the crumb porosity changed. In meat products, salt provides flavour, texture, and shelf life, and water activity increases. In this case, myofibrillar proteins’ solubility, water binding activity and colour intensity changes were found. The composition of curing nitrite salt mixtures and starter cultures must be modified.

The article presents a review of the literature on research on the development of biological products based on highly active cultures of microorganisms for the production of bakery products. The function of microorganisms and their production methods, the fermentation process of starter cultures, the role of bacteria and yeast in fermentation are considered and evaluated, a postbiotic assessment of starter cultures is carried out, and the effect of dough heat treatment on the quality of a bakery product is studied. Research confirms the possibility of increasing the efficiency and regulating the activity of microorganisms in semi-finished bakery products, which will optimize the technological process, reduce technological costs and improve the quality and safety of bakery products. It has also been established that the postbiotic components in sourdough provide beneficial properties for human health, such as better digestibility, saturation, and antioxidant properties. The properties characterizing the stability and properties of postbiotic components after the baking process have been poorly studied in studies. We have identified the need for research based on highly active cultures of microorganisms to develop bread products with postbiotic properties beneficial to the health of the country's population. Therefore, our research will focus on creating a starter culture with a specific microbiological consortium and ingredients that has the ability to enhance nutrients and benefit human health, as well as on developing an effective method for the industrial cultivation of microorganisms for the production of bakery semi-finished products, liquid yeast and starter cultures.

Sourdough bakery products have a wide range of tastes and aromas, an extended shelf-life, and other benefits that are important for food producers and consumers. Recent years have seen a growing research interest in the microbiome of bakery sourdoughs. The research objective was to generalize, systematize, and analyze modern data on spontaneous fermentation starters, their production methods, and their role in the technological process at modern bakeries. The study featured domestic and foreign monographs, research articles, and patents related to various aspects of the production and commercial use of spontaneously fermented baking starters. The search covered publications indexed in PubMed and eLIBRARY.RU in 2000–2022. The sources were selected based on such indicators as completeness, consistency, reliability, and relevance. The obtained data were analyzed and systematized in line with the method of apperception and holography. The analysis focused on the factors that affect the microbiome of baking starter cultures, in particular, spontaneous fermentation. Another aspect included the effect of the raw materials used at the stage of breeding spontaneous fermentation starter cultures on their quality indicators. The transformation of bioactive compounds in the process of sourdough fermentation proved to be an increasingly relevant research matter. Food producers are looking for more effective tools to develop bakery products with specific nutritional properties, e.g., lower glycemic index, increased content of bioactive nutrients, reduced acrylamide content, low gliadin allergenicity, etc. The isolation and profiling of microorganisms included in the microbiome of spontaneous fermentation sourdough cultures is of practical interest because new strains might produce starter cultures intended for various target audiences.

Chapter 4 - Non-Saccharomyces Yeasts in the Winemaking Process

Recently, the tradition of baking sourdough bread has been revived all over the world. The Industrial Revolution has radically changed the technology of making bakery products. Information about the dangers of high-speed yeast is rapidly spreading, which makes the consumer think about the benefits of the products consumed. Technologists of the baking industry, in turn, this forces them to return to their origins and develop recipes for healthy traditional bread according to international standards. During the research, three samples of starter cultures for whole-grain bread based on decoctions from hop cones were developed. Hop cones contribute to obtaining an optimal starter culture and the successful reproduction of yeast flora in it. They help to activate the fermentation process. They contain a large amount of antioxidants, which increases the shelf life of bread and allows it to be enriched. A comparative analysis of the activity of yeast cells in the hop ferments being developed using the Goryaev chamber was carried out. Counting of yeast cells showed that in the samples of hop starter cultures No. 1 and No. 2, their number differs slightly and amounts to 6.75·108 cl/cm3 and 6.25·108 cl/cm3, respectively. In sample No. 3, the content of yeast cells turned out to be slightly less than in the others. This indicates that in the production of bread with the use of this hop starter, the fermentation operation will take a longer time. The analysis of the technological process of preparing starter cultures of samples No. 2 and No. 3 showed that in sample No. 3 it is quite time-consuming and time-consuming. The results obtained on the development of samples of hop starter cultures indicate the possibility of their application in the technology of whole grain bread products.

This article aims to describe non-Saccharomyces yeast and their effects on wine composition, fermentation, chemistry and organoleptic characters. The use of non-Saccharomyces yeast is on the rise in the wine industry despite the negative perception from previous research. It is known that higher levels of non-Saccharomyces yeast could cause implications during winemaking practices. On the contrary, non-Saccharomyces yeast provides complexity, richer aroma and flavour and decreases ethanol content. If the main goal is using indigenous yeast and having a starter culture, use of non-Saccharomyces yeast collected from winery environment could be an option, yet again a risky option. However, previous studies indicated the relation between acetic acid production and the use of non-Saccharomyces yeast. In brief, it is important to increase sanitation in the winery environment and personal awareness to maximize cleanliness and to reduce any unwanted yeast activity. More importantly, in the recent years, the use of non-Saccharomyces yeast is attracting winemakers to achieve unique wine styles, and it is an important topic that should be taken under consideration, particularly on a research basis, specifically for targeting consumer liking-perceptions of the wine. In addition to their positive effect on sensory characters on wines, non-Saccharomyces yeasts as bio-control agents (BCAs) is also charming researchers around the globe.

Early fermentation volatile metabolite profile of non-Saccharomyces yeasts in red and white grape must: A targeted approach

Today, the use of selected commercial yeasts (LSA) from Saccharomyces species sensu stricto is widespread, because it allows to minimize risks in the production process, to standardize the winemaking procedure and ensure the quality of the final product. On the other hand, the widespread use of starter cultures in the wine industry has resulted in a loss of wine sensory characteristics and in a flattening of those differences crucial to distinguish wines of different cultivars. For this reason, the research is focused on studying new selected yeast cultures that can give a final product enrich of those aromatic compounds which enhance the character of the wine. It is known that the production of many of this aromatic molecules occurs due to the presence of non-Saccharomyces yeasts, found on the grapes and must. These non-Saccharomyces yeast strains predominate in the first phase of the alcoholic fermentation, are able to release metabolites and enzymes, responsible of the aromatic complexity of the wine. Indeed, experimental tests have shown the positive role of non-Saccharomyces yeasts in the fermentation, improving the behavior of the starter and increasing the complexity of the composition of the wine, in particular, the chemical and sensory properties. The biochemical transformation of flavour-inactive grape juice constituents into aromatic components has emerged, as an important, additional mechanism whereby yeasts substantially impact on wine aroma and flavour and facilitate greater expression of grape varietal character. In addition to ethanol, produced of the primary alcoholic fermentation, there are numerous compounds such as esters, higher alcohols, aldehydes, acids, terpenes, ketones, that determine the final quality of the product. The yeasts have the ability to produce these compounds, but it is the quantitative level that determines the difference between the different species and then, within the same species, between different biotypes. The wine yeasts for starter culture development have been sourced from grapes, winery environment or old cellars and spontaneous fermentations that have given wines of acceptable or unique quality. They are selected based on characteristics such as vigor fermentative, alcoholigenous power and they should be tolerant to the antioxidant and antimicrobial compounds, produce minimal foam, as well as produce a balanced array of flavour metabolites, without undesirable excess of volatile compounds and produce enzymes that transform the neutral compounds in flavor active component. Glycosidases and esterases are some of the enzymes produced by yeasts that can make a significant contribution to the aroma of the wine. In particular, the non-Saccharomyces yeasts have more enzymatic activities respect to yeasts S. cerevisiae. The aim of this work was the selection and use of autochthonous yeast strains isolated from cultivars of Vitis Vinifera of southern Italy and their impact on aroma profile of wines. We have tested different combination of autochthonous yeasts (S. cerevisiae and non-Saccharomyces) to improve the quality and organoleptic characteristics of the final product but also to emphasize its link with the territory and the ancient wine cultivars. In order to evaluated the aromatic profile, the different wine samples were characterized by Solid Phase Micro Extraction-Gas Crhomatography/Mass Spectrometry (SPME-GC/MS technique).

Screening and characterization of indigenous Saccharomyces cerevisiae and non-Saccharomyces yeasts isolated from Sicilian vineyards