Determination of the appropriate extraction method for bound aroma compounds from strawberry and analysis of aroma substances in strawberry fruits of different varieties and developmental stages.

Strawberries are rich in unique aroma substances, which include bound and free aroma compounds. Unlike the free aroma, the appropriate extraction and analytical methods for bound aroma compounds in strawberries remain unclear. In the present study, we compared three extraction methods for bound aroma compounds of strawberries and performed the single factor experiment for optimizing the hydrolysis method, process parameters, and response surface analysis. The following optimal process conditions were obtained for extracting bound aroma precursor compounds by the Cleanert PEP column: (1) column flow rate of 1 mL/min; (2) dichloromethane: pentane eluent ratio of 7:1; and (3) ethyl acetate: methanol retention solution ratio of 3:1. The bound aroma precursor compounds were enzymatically hydrolyzed at 38 °C for 48 h and finally detected by GC-MS. The results showed that HY strawberries at red fruit stages had the most abundant aroma content and types, and different varieties had different aroma types.