Abstract
Okinawa Prefecture is located in the southernmost part of Japan and a lot of fruits such as pineapples, mangoes, papayas and bananas are produced. Pineapple fruits on Okinawa have been mainly processed to canned pineapple. The Japanese government released the foreign trade restriction of canned pineapples and pineapple juice in accordance with GATT in April 1990, which dealt a severe blow to the Okinawan pineapple industries. Since then, the Okinawa prefectural government has been promoting productivity of fresh tropical fruits. However, as the tropical fruits are graded based on the producer's experience and intuition, the quality is uncertain. To ensure sales of high quality tropical fruits, it is necessary to employ non-destructive quality detection and sort pineapples and mangoes using Near Infrared Spectroscopy (NIR) to determine the principal sugar and acid content as essential components of quality. The results of NIR analysis suggested the possibility of predicting the sugar content in pineapples and mangoes. The sugar contents of these fruits were correlated to a specific wavelength such as near infrared absorption band of water.
