Preservation of non‐Saccharomyces yeasts: Current technologies and challenges

Abstract

There is a recent and growing interest in the study and application of non‐Saccharomyces yeasts, mainly in fermented foods. Numerous publications and patents show the importance of these yeasts. However, a fundamental issue in studying and applying them is to ensure an appropriate preservation scheme that allows to the non‐Saccharomyces yeasts conserve their characteristics and fermentative capabilities by long periods of time. The main objective of this review is to present and analyze the techniques available to preserve these yeasts (by conventional and non‐conventional methods), in small or large quantities for laboratory or industrial applications, respectively. Wine fermentation is one of the few industrial applications of non‐Saccharomyces yeasts, but the preservation stage has been a major obstacle to achieve a wider application of these yeasts. This review considers the preservation techniques, and clearly defines parameters such as culturability, viability, vitality and robustness. Several conservation strategies published in research articles as well as patents are analyzed, and the advantages and disadvantages of each technique used are discussed. Another important issue during conservation processes is the stress to which yeasts are subjected at the time of preservation (mainly oxidative stress). There is little published information on the subject for non‐Saccharomyces yeast, but it is a fundamental point to consider when designing a preservation strategy.

Yeast mannoproteins: Organoleptic modulating functions, mechanisms, and product development trends in winemaking

“…However, the impacts of these genes in the production of MPs reported by researchers indicate that the modification of the culture conditions that influence the depression or overexpression of specific genes in certain yeasts could be considered to produce or release more MPs during the yeast cultivation (Gonzalez-Ramos et al, 2008;González-Ramos et al, 2010;Quirós et al, 2010). Except for the modern genetic method, traditional yeast-breeding methods including hybridization and mutagenesis were also found to be capable of breeding new types of yeasts that exhibited higher MPs production than their parental yeasts (Braschi et al, 2019;López-Malo et al, 2015;Pérez-Través et al, 2015) In recent decades, many researches have been conducted to explore the positive impacts of the non-Saccharomyces yeasts on wine quality, including their ability to improve wine aroma, stabilize wine pigments, and produce other metabolites that benefit wine quality (Casas-Godoy et al, 2021;Vejarano, 2020). Compared with the S. cerevisiae yeasts traditionally used in wine fermentation, one of the advantages many non-Saccharomyces yeasts exhibited during their growth was that they produced relatively higher amount of MPs (Table 5).…”

“…In recent decades, many researches have been conducted to explore the positive impacts of the non‐ Saccharomyces yeasts on wine quality, including their ability to improve wine aroma, stabilize wine pigments, and produce other metabolites that benefit wine quality (Casas‐Godoy et al., 2021; Vejarano, 2020). Compared with the S. cerevisiae yeasts traditionally used in wine fermentation, one of the advantages many non‐ Saccharomyces yeasts exhibited during their growth was that they produced relatively higher amount of MPs (Table 5).…”

“…After ascertaining the acceptability, functionality and safety of these new MP products in a laboratory scale, the exploration of proper preservation/cultivation conditions and inoculation methods to satisfy the needs of specific non‐ Saccharomyces yeasts for the maximum MPs production should be the key points of the investigations in the future, in order to establish a yeast cultivation system for the production of MPs in an industrial scale. Given the emerging trend of the commercial development of non‐ Saccharomyces yeasts, the patents of Saccharomyces yeasts already authorized may be referenced and further modified for the development of non‐ Saccharomyces yeast products (Casas‐Godoy et al., 2021; Gélinas, 2019).…”

Research Progress on Nutritional Value, Preservation and Processing of Fish—A Review

“…Fish and fish-based products are usually used to preserved by various techniques at a very low temperature. There are several techniques such as cooling, freezing, icing and super-chilling that have been used to improve the preservation quality of fish [ 46 ] ( Figure 2 ).…”

Genetic diversity of non-Saccharomyces yeasts associated with spontaneous fermentation of Cabernet Sauvignon wines from Ningxia, China

“…The research on the isolation, identification and enological characteristics of non -Saccharomyces yeasts is one of the research hot spots at present, which provides a reliable reference for the exploring of local non -Saccharomyces strains with great industrial potential ( Casas-Godoy et al, 2021 ). Considering the great diversity and potential applications of different non- Saccharomyces yeast strains within the same species, it is important to discriminate them at both species and subspecies level for subsequent study.…”