Effect of Extraction and Detannification Methods on Cashew Apple Juice and Wine Quality in Vietnam

The cashew apple (Anacardium occidentale L.), is a pseudofruit that grows alongside the cashew nut (true fruit) on the cashew tree. The cashew apple is a good source of nutrients and bioactive compounds. However, it is highly perishable and has an astringent, unpalatable taste, which has limited the utilisation of cashew apples in the food industry. The study focused on evaluating the impact of various extraction methods (hydraulic pressing, screw pressing, and blending) on the quality of cashew apple juice and wine and also aimed to compare the effects of using gelatin powder versus gelatin solution for astringent tannin removal. The results showed that the hydraulic pressing had the least impact on the fruit skin, resulting in the highest clarity for both the hydraulic pressing juice and the treated hydraulic pressing juice. A gelatin solution was more cost-effective than a gelatin powder to achieve the same desired level of tannin reduction. A strong correlation (r=0.992) was established between the gelatin dosage required and the initial total tannin content of the cashew apples to remove tannins effectively. The cashew apple wine, which was fermented from specific dry yeast Saccharomyces cerevisiae RV-002 in treated hydraulic pressing juice, is classified as a low-alcohol (ABV<10%), sweet wine (residual sugar 35-120 g/L), with antioxidant activities comparable to Vietnamese commercial red wine.