Enhancing antioxidant activity and fragrant profile of low-ethanol kiwi wine via sequential culture of indigenous Zygosaccharomyces rouxii and Saccharomyces cerevisiae

To explore a novel producing strategy for enhancing antioxidant activity and aroma of low-ethanol kiwi wine,kiwifruit juice was sequential fermentation with indigenous Zygosaccharomyces rouxii(Zr)and Saccharomyces cerevisiae(Sc)without adding sugars.The organic acids,bioactive compounds,volatile constituents,antioxidant capacities and sensory profiles were measured to evaluate the performance of different inoculation ratios.The results indicated that compared with pure fermentation of Sc,the sequential fermentations significantly increased the total flavonoids,total phenols,some mono-phenols and antioxidant activities of the low-ethanol kiwi wines,and resulted in a positive effect on organic acids mainly by reducing the content of malic acid.At the same time,sequential fermentations significantly enhanced the aroma profile of the low-ethanol kiwi wines.The higher inoculation ratio of Zr greatly increased the complexity of the volatiles,improving sweet odor of the wines.While the similar inoculation ratio of Zr and Sc significantly increased the volatile contents,intensifying the tropical fruity and kernel fruity.In addition,the partial least-squares regression analysis showed that aldehydes resulted in sourness,ethyl esters and acetate esters possessed a positive impact on tropical fruity and kernel fruity.

Fermentation characteristics and flavor properties of Hericium erinaceus and Tremella fuciformis fermented beverage

This study evaluated and compared the fermentative and flavor properties of Hericium erinaceus and Tremella fuciformis fermented beverage(HTFB)produced by four commercial lactic acid bacteria(LAB),i.e.,L.plantarum,L.rhamnosus,L.paracasei or S.thermophilu s.All four strains showed the probiotic potential of utilizing Hericium erinaceus and Tremella fuciformis as fermentation substrates.Among four LAB,L.plantarum produced significantly highest concentrations of total acids(76.16 g/L),while the viable count of HTFB inoculated with L.paracasei was the highest(7.18 log CFU/mL).The contents of bioactive components such as polyphenols and triterpenoids significantly increased after fermentation regardless of the strains.The fermentation process enriched the volatile profile and reduced the unpleasant flavors such as nonanal and 1-octen-3-ol.According to the relative odor activity values and PLS-DA analysis,a total of 8 volatile organic compounds were identified as markers with odor contributions.Furthermore,the olfactory characteristics of the four beverages could be clearly distinguished by electronic nose.The electronic tongue results showed that the fermentation process increased the sourness and decreased the bitterness and astringency of the beverage,resulting in an improved taste property.The sensory evaluation finally confirmed that HTFB inoculated with L.paracasei was the most acceptable product to consumers with high overall flavor coordination.Overall,this work provided valuable information for the selection of premium fermentation strains to produce fermented edible fungi beverages with better nutritional and sensory qualities.