Effect of UV-C irradiation and storage at the different concentration of brine and vinegar on the quality and shelf life of desert truffle (Terfezia claveryi)

The present study was carried out to determine the effects of UV irradiation on postharvest and quality of desert truffle. in order to increase the shelf life of desert truffles, truffles were irradiated with UV-C (2.2 mW cm -1) at three different times, (control), 10 and 20 minutes and also storage in 7%, 10%, 13% 16% (w/w) NaCl and 5% vinegar solution (w/w). After applying the desired treatments, truffles were stored at 4 ° C for 160 days and sampling was performed at 40-day intervals. Weight loss percentage, tissue firmness, phenolic compounds, vitamin C content and microbial load were evaluated. Tissue firmness was higher at the truffles that were exposed to radiation for 10 minutes than other treatments. Also, radiation had a significant effect on preventing weight loss of truffles. The lowest weight loss was related to 10 minutes of radiation treatment and also, the highest amount of weight loss was related to control treatment. Radiation at higher doses does not further improve tissue quality parameters and causes skin necrosis and damage to truffle tissue. Evaluation of truffles phenolic compounds such as caffeic acid, ferulic acid, vanillic acid, coumaric acid, cinnamic acid and catechin was measured by HPLC. Evaluation shows that radiation had a significant effect on the increase of phenolic compounds in truffles, however the amount of these compounds decreased significantly over time. Irradiation also had a significant effect on reducing the microbial load and irradiated truffle had the lowest amount of microbial growth. However, the most effective treatment to maintain tissue quality characteristics and prevent weight loss and inhibit bacterial spoilage, UV-C (10 minutes) and immersion in vinegar and Storage at 4 ° C compared to other treatments was expressed during 160 days of storage.