Application of strains ofGeotrichumspp. to decrease higher alcohols and to increase esters

Comparison of Aroma Compounds in Cabernet Sauvignon Red Wines from Five Growing Regions in Xinjiang in China

A total of 55 volatiles including esters (29, 52.73%), alcohols (10, 18.18%), acids (3, 5.45%), alkanes (8, 14.55%), and other components (5, 9.09%) were evaluated in five regions. Total concentrations were 0.05–222.23 mg/L, which covered the highest esters (222.23 mg/L) and alcohols (120.65 mg/L) in Turpan, acid (0.53 mg/L) in Shihezi, and alkanes (1.43 mg/L) and others (3.10 mg/L) in the Ili River valley. It proved that numbers and concentrations of volatile compounds, including common ingredients of variety, were closely linked to ecological characteristics of a region. Esters and alcohols were the major ingredients in Xinjiang Cabernet Sauvignon wine. Additionally, appellation could affect performance of concentration, ODE, and OTH, especially for the same flavor substance by fermentation, aging, and even formation and transformation in wines. Therefore, three conditions for formation of flavors were successively appellations, metabolism and fermentation, and and appropriate altering according to technology and their decisive role in wine quality. Each volatile compound had its own flavor, the combination of which complicated the flavor. The unique materials in the region were grounded for the development of products with corresponding flavors by producing substrate for fermentation. When choosing a wine you enjoy, the right appellation should be considered first.

Evaluation of mixed-fermentation of Saccharomyces cerevisiae with Saprochaete suaveolens to produce natural fruity beer from industrial wort

Fruity beers can be promoted through production of flavoring compounds during fermentation by partial replacement of brewing yeast by non-conventional-yeasts with high aroma production abilities. We evaluated here the use of a wild Saprochaete suaveolens strain, producing atypical aroma compounds, to produce new natural fruity beer, while keeping classical production conditions used in brewing industry. S. suaveolens was inoculated as starter of culture during beer fermentation and the fermentation performance was evaluated through measurement of several physicochemical parameters. The aroma profile of the engineered beers was monitored using HS-SPME GC/MS. The results showed that high fruity aroma and low-ethanol content beers were obtained through single-fermentation using S. suaveolens. We also demonstrated that during mixed-fermentation, S. suaveolens maintained high metabolic activity and allowed production of beer enriched with fruity aroma. Production of high or low ethanol content fruity beer could be achieved by varying the composition of the starter of culture.

Profiling of Fungal Diversity and Fermentative Yeasts in Traditional Chinese Xiaoqu

To increase the safety and quality of baijiu and rice wine in China, controlling the use of traditional Xiaoqu by studying the beneficial yeasts present has recently been considered. The fungal diversity of six Chinese Xiaoqu including five traditional and one commercial samples was investigated to screen fermentative yeasts with low yields of higher alcohols. A high throughput sequencing approach detected fifteen fungal species with relative abundance higher than 1%, and displayed dissimilarities of fungal diversity among Xiaoqu samples. The 15 fungal species were composed of 11 filamentous fungi with Rhizopus arrhizus as the most common specie and four yeast species, containing Hyphopichia burtonii, Saccharomyces cerevisiae, Saccharomycopsis fibuligera, and Saccharomycopsis malanga. Classic culture-dependent approaches, including 5.8S-ITS-RFLP analysis and D1/D2 sequencing of the 26S rRNA gene, identified nine yeast species in the five traditional Chinese Xiaoqu. In addition to the four yeast species also detected by high throughput sequencing approach, the other five yeast species isolated were Clavispora lusitaniae, Cryptococcus neoformans, Komagataella pastoris, Trichosporon asahii, and Wickerhamomyces anomalus. Further micro-fermentations of rice wine were performed using 19 single yeast isolates, and after the fermentation of rice wine, higher alcohols and ethanol were analyzed by gas chromatography. Two yeast strains, Saccharomyces cerevisiae FBKL2.8022 and Wickerhamomyces anomalus FBKL2.8023, were found to have low yields of higher alcohols and could produce 11.70%vol and 7.10%vol ethanol separately. This study for the first time, to the best of our knowledge, explored the fungal resources in traditional Xiaoqu from different regions of Guizhou, China. The screened S. cerevisiae and W. anomalus strains could be used to establish specific starters to promote the standardization of the production of baijiu and rice wine.

Analysis of Volatile Compounds and Sugar Content in Three Polish Regional Ciders with Pear Addition

Aroma plays important part in cider acceptability to the consumer. In this study, techniques such as headspace solid-phase microextraction (HS-SPME), which has been coupled with gas chromatography and mass spectrometry, have been used to assess what changes in the volatilome occur during fermentation of three apple cultivars (Cortland, Gala, Idared) with and without addition of pear (Konferencja) juice addition. Analysis of volatiles has shown that temperature of fermentation, apple variety and pear juice addition have significant influences on the volatile compositions of the acquired ciders. Ciders prepared in laboratory conditions fermented at 15 °C were characterized by a greater share of esters, such as ethyl hexanoate, ethyl decanoate and ethyl dodecanoate, in volatile profile (66.24–79.58%) than ciders fermented at 20 °C (58.81–77.22%). Ciders fermented at a higher temperature were characterized by a greater share of alcohols, such as phenylethyl alcohol and hexan-1-ol (18.34–36.7%) than ciders fermented at a lower temperature (16.07–25.35%). In the ciders prepared from pear (20% w/w) and apple (80% w/w) juice, the presence of esters, such as ethyl (2E, 4Z)-deca-2,4-dienoate, characterized by a pear aroma, could be noted.

Changes in anthocyanins and volatile components of purple sweet potato fermented alcoholic beverage during aging

Purple sweet potato was fermented into alcoholic beverage. By using LC-MS analysis, 12 types of anthocyanins were found in the purple sweet potato alcoholic beverage (PSPFAB); these were based on cyanidin and peonidin as aglycones. The anthocyanins in young PSPFAB mainly consisted of acylates. The acylated anthocyanins, however, degraded gradually with aging. Cyanidin 3-sophoroside-5-glucoside and peonidin 3-sophoroside-5-glucoside were found to be major anthocyanins in the PSPFAB after two years of aging. Moreover, 52 kinds of volatile components were detected in PSPFAB by GC-MS analysis. Alcohol and ester substances constituted a major proportion of these volatile components of PSPFAB. After two years of aging, levels of high-alcohols such as 1-pentanol remarkably decreased to below the detection limit, while the level of total esters increased significantly. Such variation of aromas enriched and improved the flavor of PSPFAB.