Characterization of flavor quality deterioration of postharvest Chinese bayberry (Myrica rubra cv. Dongkui) at different storage temperatures

The present study characterized the flavor quality deterioration of ‘Dongkui’ Chinese bayberry (Myrica rubra) stored at different temperatures. The fruit were stored at 0 °C, 4 °C, 10 °C and 20 °C for 12 d. The quality deterioration was characterized by combining human sensory evaluation and artificial sensory evaluation, which included e-nose and e-tongue. The sensory quality deterioration was characterized in the aspects of taste strength, bitterness, and odor, in which the odor was found to be most related to the sensory quality deterioration. In the artificial sensory evaluation, 12 e-nose sensors showed differential responses with the elongation of storage time and temperature. Based on the human sensory evaluation and the response values of the 12 e-nose sensors, the stored fruit were classified, with those stored at 20 °C for 2 d or longer and those stored at 10 °C for 7 d or longer classified as “off-flavored” fruit. The artificial neural network (ANN) model verified the classification. A total of 27 volatile compounds were identified by HS-SPME–GC–MS. Eight differential volatiles were screened out with p < 0.05 and variable importance in projection (VIP) > 1 by orthogonal partial least squares discriminant analysis (OPLS-DA). Among these volatiles, (Z)-3-hexenoic acid methyl ester and (E,E)-2,4-hexadienal decreased, while octanoic acid, acetaldehyde, ethanol, phenylethyl alcohol, 2-pentylfuran and benzaldehyde increased in the deteriorated fruit.