Comparison of technological methods for astringency removal in introduced persimmon (Diospyros kaki L.) varieties

The aim of the research was to select effective and technologically rational methods for removing astringency from the fruits of industrial persimmon varieties common in Georgia immediately after harvest. The study involved the testing of three different methods: warm water treatment (40°C for 4–4.5 hours), freezing (−20°C for 3 and 6 hours), and carbon dioxide treatment (CO₂, 95% at 20°C for 16 and 24 hours). Samples treated by each method were stored at a temperature of 0–1°C with a relative humidity of 90–95%. According to the results, warm water treatment reduces astringency and improves organoleptic indicators; however, it causes fruit softening and deterioration of visual characteristics, with the effect appearing only after 7–10 days. The freezing method ensures rapid astringency removal (20–24 hours) but leads to tissue darkening and reduces shelf life. The best results were achieved with a 24-hour CO₂ treatment, where astringency completely disappears after 3 days, the fruit retains its original color, shape, and firmness, and the shelf life reaches 60–70 days. The conducted research reveals that CO₂ treatment is the most effective method, ensuring the preservation of both taste and visual qualities.