Cooking Methods Alter Bioaccessibility of the Bioactive Compounds in Purple Potato (Solanum tuberosum L. var. Bora Valley)

초록

Purple potato (Solanum tuberosum L. cv. Bora Valley) is a nutrient source rich in bioactive compounds. However, the cooking methods either significantly affect retention of bioactive compounds or reduce them in the potatoes. The results of this study showed that the water solubility of the bioactive compounds was significantly higher in boiled potato (37%) compared to raw (31.3%) and steamed (30.9%) potatoes. The smallest nano-size particles were obtained from boiled potato (124 nm), followed by the steamed (138 nm) and raw (166 nm) potatoes. The total phenolic content in the boiled potato (3774 mg/100 g) was higher than in the steamed (2026 mg/100 g) and raw (3169 mg/100 g) potatoes. Likewise, the levels of single phenolic acids, such as caffeic and ferulic acid, increased, while the ascorbic and chlorogenic acid levels decreased in boiled potato. The total flavonoid and total anthocyanin contents were reduced by both cooking methods. Chromatographic analysis showed that the levels of the only pelargonidin increased but those of cyaniding, delphinid, and malvidin decreased in cooked potatoes compared to raw potatoes. However, the antioxidant capacity increased in boiled potatoes (37.6%) compared to the steamed (29.8%) and raw (29.9%) potatoes. The scanning electron microscopic analysis showed well- dispersed nano-size particles in boiled potatoes, while flocculated particles were observed in the steamed and raw potatoes. Finally it is concluded that boiling is the most suitable cooking processes to retain higher functional bioactive compounds in purple potato.

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