New approach for non-destructive sensing of fruit taste

Abstract

A new method for the non-destructive sensing of fruit taste has been proposed for Japanese orange, one of the products of the Kumamoto area. Oranges contain sugars and acids, which are easily analysed by HPLC using the juice of the fruit, and the taste of oranges can be given primarily by the sugars/acids ratio. On the other hand, the intensity of the non-destructive Raman signal due to carotenoids around 1155 and/or 1525 cm −1 obtained from the surface of orange peel using Ar + laser light (e.g., 514.5 nm) increase during ripening of the orange, reaches a maximum at harvest time and then decreases. Interestingly, the Raman signal intensity obtained from the peel is found to show a good correlation with the data on sugars/acids ratios of the orange juice, suggesting that the Raman intensity from the peel of oranges cna be used as a measure of the taste for screening the sweetness of oranges. This technique, together with some other methods, has also been applied to muskmelon to evaluate the sweetness non-destructively.