Changing patterns of Bioactive Compounds according to the Ripening Stages of Strawberry (Fragaria × ananassa Duch.) with Different Fruit Skin Colors
As a result of analyzing bioactive compounds according to the maturity stage of strawberry fruits, there was no difference in callistephine content according to the extraction solvent and tended to increase as the maturity stage progressed. There was a difference in accumulation patterns between cultivars with different fruit colors, but the callistephin content of the red strawberry, Seolhyang, was high, while the pink strawberry, Manyeonsel, tended to be low. The extraction efficiency of cyanidine-3-glucoide was higher when water was used as the extraction solvent than ethanol, which was the highest in the green stages in both cultivars and tended to decrease as the maturity stage progressed. The (+)-catechin content according to the maturity stage showed the highest content in the green stages overall, and tended to decrease as the maturity stage progressed. The extraction efficiency of (+)-catechin was good in ethanol, and the (+)-catechin content according to the maturity stage was generally high in the green stages and tended to decrease as the maturity stage progressed. The catechin content in green stages of Manyeonsel was 205.3 mg per 100 g of dry weight, which was very high compared to 115.6 mg in the Seolhyang. The extraction efficiency of epi-catechin was better in water than in ethanol, and the content of epi-catechin tended to be higher in Seolhyang than in Manyeonsel. When extracted with water, the epi-catechin content of Seolhyang increased 16.0-fold from 15.7 mg per 100g dry weight in green stages to 250.3 mg in mature stages, and 3.1-fold from 50.1 mg to 154.2 mg in Manyeonsel. The content of quercetin-3-glucoside tended to be higher when ethanol was used as an extraction solvent than water, and it was 12.2 and 15.7 mg per 100 g of dry weight in Seolhyang and Manyeonsel, respectively, in the highest-content green stages. Quercetin had a higher extraction efficiency from ethanol than water, which tended to be slightly higher, at 2.5 mg in the mature stages of Seolhyang, while at 3.2 mg in Manyeonsel. The extraction efficiency of chlorogenic acid was higher in water than in ethanol, and the content was highest in the green stages and tended to decrease as maturation progressed. When extracted with water, the content in the green stages of Seolhyang and Manyeonsel decreased by 45.3 and 33.9%, from 14.8 and 18.9 mg, respectively, to 8.1 and 12.5 mg during the mature stages, respectively. The content of ellagic acid tended to be higher when water was used as an extraction solvent than ethanol, but there was no difference in content according to maturity stages in the two cultivars. The cinchonine was more efficient in extraction from water than ethanol and tended to increase as the maturation stage progressed in both varieties, the highest at 148.6 mg per 100 g of dry weight in the mature stages of the Manyeonsel.