• Preventive Nutrition and Food Science
• /
• v.1 no.2
• /
• pp.252-255
• /
• 1996

As an index of freeze-injury of yeast, the leakage of intracellular substances from yeast cells after freeze-thawing was investigated. It was found that much more ultraviolet-absorbing substances leaked out from non-freeze tolerant yeast (NETY) than from freeze-tolerant yeast. Furthermore, the rate of leakage of cellular substances form NFTY during incubation exceeded that of FTY, indicating that NFTY is more susceptible to freeze-injury than FTY during frozen-storage. An apparent degradation of phospholipid was observed during incubation of perfermented frozen-cells of NFTY, while little change of phospholipid occurred in FTY, These results suggested that the difference in the sensitivity of yeast might be due to the strength of cell membrane in terms of the degradation of phospholipid by enzymes, phospholipases, attached to cell membranes.

• Korean journal of food and cookery science
• /
• v.11 no.1
• /
• pp.9-12
• /
• 1995

The molar ratio of sterol to phospholipid differed from yeast strains, and the ratio was relatively higher in non-freeze-tolerant yeast strain, S. cerevisiae than freeze-tolerant yeast strains, D$\sub$2-4/ or CFY. Phospholipid composition of these yeast were also investigated. Phosphatidylcholine content was larger among phospholipids in all yeasts. Higher ratio of PC/PE was found in freeze-tolerant yeast than non-freeze-tolerant yeast. Higher proportion of linolein acid(18 : 2) against total fatty acid attached to phospholipid was observed in D$\sub$2-4/ than S. cerevisiae or CFY, and the degree of unsaturation of fatty acid was higher in D$\sub$2-4/ and CFY than in S. cerevisiae. These results suggested that the fluidity of yeast cell membrane was different in yeast strains, which might result in the difference in freeze-injury of yeast at low temperatures.

• Food Science and Preservation
• /
• v.19 no.3
• /
• pp.413-419
• /
• 2012

Fermentation of ice apple wine from freeze-concentrated Fuji apple juice to 36 $^{\circ}Brix$ was carried out using Saccharomyces cerevisiae SS89, a sugar-tolerant wine yeast strain. The characteristics of the fermentation and the properties of ice apple wine were compared with those of S. cerevisiae W-3, an industrial wine yeast that was used as a control in this study. During the fermentation, the alcohol content increased more rapidly by S. cerevisiae SS89 together with the decrease of the soluble solid content, compared to S. cerevisiae W-3. It reached 12% (v/v) after 15 days of fermentation by S. cerevisiae SS89 (12.4%, v/v) and 21 days by S. cerevisiae W-3 (12.6%, v/v). The soluble solid contents of the SS89 and W-3 wines were 24.0 and 23.6 $^{\circ}Brix$, respectively. Lactic acid was detected at the highest level, followed by malic aid, among the organic acids in both wines. No big differences in the organic acid contents were observed based on the strains. In the SS89 wine, higher levels of methanol, propanol, butanol, and isoamyl alcohol were detected, together with a lower isobutanol content, compared with the W-3 wine. The SS89 wine showed higher level of intensity as well as higher Hunter's L and b color values compared to the W-3 wine. In the sensory evaluation, similar scores in color, flavor, taste, and overall preference were obtained in the two wines. Therefore, S. cerevisiae SS89 was thought to be useful for the rapid fermentation of ice apple wine.