The aim of this study is to develop and validate an improved analytical method for the simultaneous quantification of 20 types of mycotoxins in grapes and wines. In this research, the optimization of tandem mass spectrometer (MS/MS) parameter, ultra-high pressure liquid chromatography (UHPLC) separation, and QuEChERS procedure, which includes wine/water ratio, the amount and type of salt, clean-up sorbent, were performed, and the whole separation of mycotoxins was accomplished within 7 min analyzing time. Under optimum conditions, recoveries ranged from 85.6% to 117.8%, while relative standard deviation (RSD) remained between 6.0% and 17.5%. The limit of detection (LOD, 0.06–10 μg/L) and the limit of quantification (LOQ, 0.18–30 μg/L) were lower than those permitted by legislation in food matrices, which demonstrated the high sensitivity and applicability of this efficient method. Finally, 36 grapes and 42 wine samples from the Hexi Corridor region were analyzed. Penicillic acid (PCA), mycophenolic acid (MPA), cyclopiazonic acid (CPA), fumonisin B1 (FB1) and zearalenone (ZEN) were detected in a small number of grape samples with lower concentrations between 0.10 μg/L and 81.26 μg/L. Meanwhile, ochratoxin A (OTA), aflatoxin B2 (AFB2), MPA, CPA, and ZEN were detected in some wine counterparts with concentrations ranged from 0.10 μg/L to 4.62 μg/L. However, the concentrations of the detected mycotoxins were much lower than the maximum legal limits set of other products.

Conventional pear–kiwifruit wine has a bland flavor and sour taste, because of excessive l-malic acid content and, consequently, little consumer appeal. An Oenococcus oeni strain, GF-2, has good malolactic fermentation (MLF) performance and high glucosidase activity. Through a Box–Behnken design, the optimum MLF parameters for deacidification by GF-2 were determined: initial pH of 3.4, 5% v/v inoculation, and temperature of 20 °C, which reduced the malic acid content by 98.3%. The changes in the content of organic acids, polyphenols, and aromatic compounds after MLF were compared with chemical deacidification. MLF significantly decreased the total concentration of organic acids by 29.7% and promoted the accumulation of aromatic esters, higher alcohols, and terpenoids, but chemical deacidification markedly decreased aromatic compound content by 59.8%. MLF wine achieved the highest sensory scores for aroma, taste, and overall acceptability. Therefore, MLF with O. oeni GF-2 has great potential to markedly improve the quality of commercial pear–kiwifruit wine.

In this study, a mixed fermentation strategy using grape-blended pear juice co-inoculated with Metschnikowia pulcherrima 346 and Saccharomyces cerevisiae ES488 was used to characterize the modifications of the flavor and antioxidant activity of Zaosu pear-Merlot grape alcoholic beverage. The optimum fermentation parameters identified using a fuzzy mathematical sensory evaluation model were an initial pH of 4.22, a ratio of M. pulcherrima 346 and S. cerevisiae ES488 inoculated 1.13:1, sequential inoculation time 47.02 h and making temperature 19 °C. The optimal mixed fermentation increased the content of terpenes and ethyl esters in pear-grape beverage by 16.5 % and 11.2 % respectively, enhancing floral and fruity aromas and attaining the highest sensory score. Due to the accumulation of flavonoid, anthocyanin, and phenol, the optimized alcoholic beverage exhibited the highest DPPH (97.6 %) and OH (93.3 %) radical scavenging rate as well as iron ion reducing power (3.25), which is conducive to extending the shelf life of beverages.