High citric acid content in kiwifruit wine would lead to bad sensory experience and quality deterioration. It is opportune and crucial to develop an appropriate and feasible method to degrade citric acid for kiwifruit wine. The non-Saccharomyces yeasts confirmed to have the ability to degrade citric acid were screened and used in kiwifruit wine fermentation in the study. A representative number of 23 yeasts with a strong citric acid degradation ability was identified by molecular approaches. JT-1-3, identified to be Pichia fermentans, was preferred for high citric acid degradation and strong stress resistance in association with RV002 (commercial Saccharomyces cerevisiae). Then it was pure-cultured in kiwifruit juice, and the results indicated that citric, malic and tartaric acids declined significantly from 12.30, 3.09 and 0.61 g/L to 11.00, 2.02 and 0.41 g/L after fermentation, respectively, resulting in the significant decrease in total acid in kiwifruit wine. The analytical profiles for amino acids and volatile compounds showed that Pichia fermentans JT-1-3 could improve amino acids’ proportion and increase the volatile compounds of alcohols, esters and phenols. This work indicated that JT-1-3 has great potential to be applied for fruit wine with high level citric acid.

In this study, we compared the quality of iron walnut oil (IWO) oleogels prepared with different oleogelators, including γ-oryzanol/β-sitosterol (OZ-PS), γ-oryzanol/triglyceride (OZ-TC), monoglycerides (MGS), beeswax (BW), beeswax-monoglycerides (BW-MGS), and carnauba wax (CW). The physicochemical and component properties, rheological and textural parameters, macroscopic morphologies, and antioxidant capacities of the resulting oleogels were analyzed. In addition, their microscopic properties were analyzed using Fourier-transform infrared (FTIR), X-ray powder diffraction (XRD) spectroscopy, and polarized light microscopy (PLM). The results showed that the gel structures produced by different oleogelators did not change the fatty acid composition of IWO. In addition, the IWO oleogel prepared with OZ-PS had a more stable network structure, excellent hardness at 4℃ (1116.51 g), better antioxidant capacity (766.50 μmol TE/kg) and higher total phenolic content (14.98 mg/kg) than any other experimental IWO oleogels. Moreover, comprehensive ranking by principal component analysis of numerous characteristics showed that the OZ-PS oleogel (2.533) ranked first among the six oleogels studied. Therefore, the IWO oleogel prepared with OZ-PS is a promising product, and our results provide guidance for the preparation of IWO oleogels, such as to increase their applications in the food industry.