Selenium loss and changes in product quality during cooking of selenium enriched potato tubers

Selenium biofortification is increasingly applied to improve selenium contents in the edible parts of crops. Potato (Solarium tuberosum L.) is a major food crop with wide availability of consumption, which is suitable for selenium biofortification. However, the processing and product quality of selenium-enriched potatoes has rarely been reported. Herein, selenium-enriched potato tubers (0.24 mg kg(-1) fresh weight) were used to investigate selenium retention, loss details, and quality changes in different processed products. Final selenium contents of the products varied with different processing methods (P <0.01). Compared to fresh tubers, steaming resulted in the lowest loss rate of selenium (28.64 %), mainly related to decoction. Moderate loss rates of selenium were recorded in boiled tubers (42.44 %), French fries (44.73 %), and crisps (50.86 %), mainly related to decoction, cutting and hot cleaning, respectively. The highest loss rate was attributed to starch extraction (98.69 %), mainly related to crude protein. Selenium application delayed enzymatic discoloration of fresh-cut tubers (P < 0.05) and increased the proportion of large- to medium-sized starch granules (>30 mu m) (P < 0.05) compared to the control. To minimize selenium loss, steaming is superior to boiling and frying for the processing of selenium-enriched potatoes, and it is not feasible to produce selenium-enriched starch.