MEASUREMENT OF FIRMNESS OF IRWIN MANGOES BY A NON-DESTRUCTIVE ACOUSTIC TESTER DURING COLD STORAGE.

Mangoes (Mangifera indica L., cv. 'Irwin ') grown in plastic greenhouses in the Okinawa Islands, Japan, were obtained and stored at 5°C, 10°C, 15°C, and in ambient conditions (20°C to 25°C) for 21 clays. Their sound velocity was recorded by an instrument named the "Firm Tester," which uses an acoustic transmission technique to indicate firmness index as a function of transmission velocity (TV). Magnitude of TV indicates fruit firmness. As the storage period advanced, the transmission velocity decreased. It was evident that ripened mangoes could be stored at 5°C without occurrence of chilling injury (CI), but non-ripened mangoes stored at the same temperature showed signs of CI. The Firm Tester provided a true firmness index of Irwin mangoes non-destructively. Commercialization of the Firm Tester could help the growers, packers, and retailers judge the firmness of fruit non-destructively. [ABSTRACT FROM AUTHOR]