Техника и технология пищевых производств (Mar 2023)
Resistance to Sulfur Dioxide as a Criterion for Selecting Saccharomyces cerevisiae for Organic Winemaking
Abstract
Sulfur dioxide is a popular conserving agent and antioxidant in winemaking. Unfortunately, it is bad for human health. Some yeast strains can reduce the dose of sulfur dioxide. Such yeasts should have good fermentation activity and dominate when inoculated into grape must. In addition, it should not synthesize sulfur dioxide and SO2-binding substances. The synthesis of sulfur dioxide and carbonyl compounds by yeast is related to the mechanisms of sulfur dioxide detoxification. The research objective was to study the relationship between the resistance of yeast to sulfur dioxide and its ability to synthesize sulfur dioxide and acetaldehyde during growth. The study featured 17 yeast strains of the genus Saccharomyces. The yeasts were cultivated on grape must in a CGQ device until the stationary growth phase. The concentration of free and bound forms of sulfur dioxide was determined by titration, while that of aldehydes was determined by bisulfite method. The sulfite resistance of strains was measured by the growth response of yeast cells to sulfur dioxide using CGQ technology. Yeast strains differed in the degree of sulfur dioxide resistance. The samples were divided according to the increase in the lag phase time: by ≥ 8 h (sensitive), by 2–6 h, without changes (resistant). At Wilks L = 0.228 and α = 0.05, the sensitive cultures in a SO2-free medium had the highest value of minimal generation time in the exponential growth phase (5.3 ± 2.1 h). The resistant samples demonstrated the highest synthesis of acetaldehyde (54.7 ± 11.1 mg/L) and sulfur dioxide (21.0 ± 10.3 mg/L). The second group cultures had the lowest content of SO2-bound forms in the medium (10.9 ± 4.2 mg/L) and were in an interposition in terms of other indicators. The time it takes a yeast strain to adapt to sulfur dioxide can be used as a parameter for the primary culture selection in eco-winemaking. According to the physiological and biochemical profile, the resistant strains can be recommended for the production of SO2-low wines, while the samples from the second test group proved optimal for organic wines. Further research will expand the range of yeast strains and their indicators.
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