Commercial Yeast Preparations Research Articles

Characterization and comparison of yeasts from different sources for some probiotic properties and exopolysaccharide production

Abstract A total of 134 strains of yeasts isolated from fruits and vegetables (certain berry fruits, apples, pomegranates, carrots and grapes), free-range chicken feces and dairy products, and from 10 commercial yeast preparations were identified and subjected to analyses to determine their in vitro probiotic properties. Based on 26S rRNA sequence analysis all ten isolates from commercial products were identified as Saccharomyces cerevisiae, and the natural isolates as Candida corpophila, Candida diddensiae, Clavispora lusitaniae, Hanseniaspora opuntiae, Hanseniaspora uvarum, Kazachstania bovina, Kluyveromyces marxianus, Metschnikowia. pulcherrima, Metschnikowia sp., Meyerozyma carribbica, Pichia kluyveri and Wickerhamomyces anomalus. All isolates were found to be resistant to simulated gastric juice at pH 2.5 for 2 h and were able to grow at both 30 and 37 °C. The exopolysaccharide (EPS) production of isolates from commercial preparations and from natural sources varied between 249-275.22 and 27.95-272.22 mg/L, respectively. Two of the natural isolates had levels of EPS production comparable to the natural strains (S. cerevisiae T8-3C and S. cerevisiae P25-1) with 264.63 and 272.53 mg/L, respectively. Isolates were also investigated for autoaggregation and coaggregation abilities. The highest coaggregation ability was determined for the Saccharomyces cerevisiae P25-1 strain against Staphylococcus aureus (ATCC 25923).

Effect of Yeasts on the Aroma Profile of Sauvignon Blanc Varietal Wine

In this study effects of commercial yeast preparations on the aromatic profile of Sauvignon Blanc varietal wine were investigated. Grape juice was divided to 7 experimental variants and fermented spontaneously and using 6 commercial strains of Saccharomyces cerevisiae. In final wine samples, essential analytical parameters and selected aromatic compounds were analysed. The highest content of esters was found out in samples fermented by spontaneous micro‑flora; in this case, concentrations of ethyl hexanoate, ethyl octanoate and ethyl decanoate were 682 µg/L, 735 µg/L and 162 µg/L, respectively. The highest content of acetates was recorded in samples fermented by yeast Vulcaferm Sauvignon; concentrations of isoamyl acetate, 2‑phenylethyl acetate and isobutyl acetate were 7.8 mg/L, 244 µg/L and 137 µg/L, respectively. Yeast strain suitable for cold fermentation (Oenoferm Fredo) produced high amounts of ethyl esters and acetates. As far as the sensory evaluation was concerned, the best rating got the sample fermented by these yeasts; it showed a high degree of smell and flavour cleanness as well as a very good overall harmony.

Comparison of Commercial and Locally Identified Yeast Strains in Relation to Young Wine Quality of Cabernet Sauvignon

The present study was conducted to evaluate the fermentation efficiency of locally identified yeast strains against the commercial yeast preparations in the case of Cabernet Sauvignon wines. For this purpose, must of Cabernet Sauvignon was inoculated separately with three each of commercial (KIV 1116, EC 1118 and Premier Cuvee) and locally identified (RS1, RS2 and RS3) yeast strains. The physicochemical parameters of wines made with these two groups of yeast strains showed significant differences during fermentation. The pH values ranged from 3.40 to 3.55, which fall in the agreeable limit. The minimum alcohol content, i.e. 10.32%, was found in the wine with maximum reducing sugars. Wine made from the inoculation of strain EC 1118 contained 11.06% alcohol. The anthocyanin content differed significantly among all the yeast strains. The maximum anthocyanin content was found in wine prepared from RS1 (15.70 g/l). Maximum colour intensity (14.66) was observed in the RS2 yeast strain. The wines made from locally identified yeast strains contained more antioxidant reducing power (FRAP) than commercially available yeast strains. Significant differences were noted among the yeast strains in relation to FRAP values. The locally identified yeast strains were found to be on par with commercial yeast strains. These strains can be used for further studies on other important varieties.

Antioxidant Properties of Sparkling Wines Produced with β‐Glucanases and Commercial Yeast Preparations

The aim of this study was to evaluate the in vitro antioxidant potential of sparkling wines produced with β-glucanases, autolysated yeasts, yeast cell walls, and purified mannoproteins. Total antioxidant capacity (measured by 2,2-diphenyl-1-picrylhydrazyl [DPPH] radical-scavenging method and ferric reducing antioxidant power [FRAP] assay), and hydroxyl radical-scavenging activity (HRSA) were higher in the wine samples with coadjuvants (in relation to the control wine). The highest values of antioxidant activity were achieved with purified mannoproteins and, in lesser extent, with β-glucanases. Neutral polysaccharides and total proteins were highly and positively correlated with DPPH, FRAP, and HRSA assays. However, correlations between the levels of each different phenolic family and antioxidant and radical-scavenging activities were not found. β-Glucanase and commercial yeast preparations can be excellent coadjuvants to increase the antioxidant properties of sparkling wines. β-Glucanase and commercial yeast preparations can be excellent coadjuvants to increase the antioxidant properties of sparkling wines. The suggested improvement has significant implication for the production of high added value sparkling wines.

Effect of the addition of β-glucanases and commercial yeast preparations on the chemical and sensorial characteristics of traditional sparkling wine

Sparkling winemaking is an increasing industry in Castilla y Leon region of Spain. Several trials have been made to improve the techniques in order to offer better products to the market. This study focuses on the evaluation of the influence of different co-adjuvants in the sparkling winemaking process (β-glucanases, autolysated yeasts, yeasts cell walls and purified mannoproteins) by measuring different oenological parameters at 3, 6 and 9 months of ageing after the secondary fermentation. Both physicochemical and sensorial analyses are considered in order to reveal the incidence of these co-adjuvants in the final product. A consumers study has also been carried out with the aim of knowing the possible impact of the co-adjuvants in the market of the so elaborated sparkling wines. β-Glucanases seem to increase the ageing characteristics of the sparkling wines, while yeast derivatives (yeast cell walls and yeast autolysates) improve their fruity and flowery character.

グルタチオンの生化學的研究(第7報)

グルタチオンの生化學的研究(第7報)