In this study, we used Chinese chestnut as the main raw material to develop a novel type of whiskey. First, 16 yeasts were isolated and identified for producing aroma using olfactory plate assay. Of these, we screened nine yeast strains based on their fermentation capacity, aroma profile, and sensory evaluation. The results demonstrated the combination of strains HN006 (Saccharomyces cerevisiae) and HN010 (Wickerhamomyces anomalus) provided satisfactory wine fermentation with an interesting flavor profile, as strain HN010 was highly aromatic and had elevated sensory scores with comparatively low ethanol yield, while strain HN006 had a poor flavor profile but produced the largest amount of ethanol. Subsequently, we co-cultured strains HN006 and HN010 to optimize the fermentation system. The results revealed the following optimum parameters: a mixed inoculum of 6% (v/v) at an HN006/HN010 ratio of 1: 2 (v/v), a raw material ratio of 5: 3: 2 (chestnut: malt: glutinous rice), and yeast extract concentration of 6 g/L. Additionally, this fermentation system was successfully scaled-up to a 1000 L pilot-scale system. The results of this study showed that strains HN006 and HN010 could be used as alternatives for whiskey fermentation, as well as provided a generalized experimental scheme to assess other microorganisms.

To optimize the process technology of yogurt fortified with M. esculenta, first, the Plackett-Burman experimental design combined with the central composite design (CCD) were used to investigate the effects of four parameters on the sensory score. Then, artificial neural networks (ANN) and genetic algorithm (GA) were used to evaluate the process parameters of the fortified yogurt. Finally, the quality of the yogurt prepared under optimal conditions were observed. The results showed that the optimal parameters from ANN-GA were: 0.2 g of mycelia, 15 g milk powder, 6.4 g sucrose, and a fermentation temperature of 38 °C, with the highest predicted sensory score of 97.1 points, which was more accurate and reliable than CCD. Mycelia of M. esculenta gave the yogurt excellent quality, including good acidity (95 ± 2.85° T) and water holding capacity (64.32 ± 4.25%) after 21 days storage at 4 °C; firmness (12.98 ± 1.25) g, consistency (22.85 ± 0.92) g•sec, stickness (-6.16 ± 0.38) g, stringiness (3.53 ± 0.12) mm, and cohesion index (-6.62 ± 1.75) g•sec. Moreover, the living lactic acid bacteria of the yogurt with M. esculenta (6.23 ± 0.23) × 10 7 CFU/mL) were significantly higher than that of the control yogurt (5.65 ± 0.31) × 10 7 CFU/mL. This could provide a theoretical basis and parameter guidance for developing a new functional yogurt.

In this study, we used Chinese chestnut as the main raw material to develop a novel type of whiskey. First, 16 yeasts were isolated and identified for producing aroma using olfactory plate assay. Of these, we screened nine yeast strains based on their fermentation capacity, aroma profile, and sensory evaluation. The results demonstrated the combination of strains HN006 (Saccharomyces cerevisiae) and HN010 (Wickerhamomyces anomalus) provided satisfactory wine fermentation with an interesting flavor profile, as strain HN010 was highly aromatic and had elevated sensory scores with comparatively low ethanol yield, while strain HN006 had a poor flavor profile but produced the largest amount of ethanol. Subsequently, we co-cultured strains HN006 and HN010 to optimize the fermentation system. The results revealed the following optimum parameters: a mixed inoculum of 6% (v/v) at an HN006/HN010 ratio of 1: 2 (v/v), a raw material ratio of 5: 3: 2 (chestnut: malt: glutinous rice), and yeast extract concentration of 6 g/L. Additionally, this fermentation system was successfully scaled-up to a 1000 L pilot-scale system. The results of this study showed that strains HN006 and HN010 could be used as alternatives for whiskey fermentation, as well as provided a generalized experimental scheme to assess other microorganisms.

Chinese strong-flavour liquor is produced via a traditional solid-state fermentation strategy facilitated by live microorganisms in pit mud-based cellars. For the present analysis, pit mud samples from different spatial locations within fermentation cellars were collected, and the yeast communities therein were assessed via culture-based and denaturing gradient gel electrophoresis (DGGE) approaches. These analyses revealed significant differences in the composition of yeast communities present in different layers of pit mud. In total, 29 different yeast species were detected, and principal component analyses revealed clear differences in microbial diversity in pit mud samples taken from different cellar locations. Culture-dependent strategies similarly detected 20 different yeast species in these samples. However, while Geotrichum silvicola, Torulaspora delbrueckii, Hanseniaspora uvarum, Saturnispora silvae, Issatchenkia orientalis, Candida mucifera, Kazachstania barnettii, Cyberlindnera jadinii, Hanseniaspora spp., Alternaria tenuissima, Cryptococcus laurentii, Metschnikowia spp., and Rhodotorula dairenensis were detected via a PCR-DGGE approach, they were not detectable in culture-dependent analyses. In contrast, culture-based approaches led to the identification of Schizosaccharomyces pombe and Debaryomyces hansenii in these pit mud samples, whereas they were not detected using DGGE fingerprints profiles. An additional HS-SPME-GC-MS-based analysis of the volatile compounds present in fermented grains samples led to the identification of 66 such compounds, with the highest levels of volatile acids, esters, and alcohols being detected in fermented grains from lower layer samples. A canonical correspondence analysis (CCA) suggested they were significant correlations between pit mud yeast communities and associated volatile compounds in fermented grains.