ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Detection of bruises on apples by near infrared reflectance spectroscopy

Guillermin P.; Camps C. and Bertrand D.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.117

2004

บทคัดย่อ

The objective of the study was to evaluate the interest of near infrared reflectance spectroscopy (NIRS) to detect the bruises caused o­n apples by a definite compression test. Three varieties (Elstar, Gala, Smoothee) and six stages of fruit development were compared. The spectra were acquired o­n a KIR spectrometer at wavelength ranging from 800 nm to 2200 nm.

Six harvest were achieved, from mid may to mid September, with thirty fruits per harvest for each condition (variety x date). Spectra were first acquired o­n the less coloured side of the intact fruits. Two successive compressions at constant speed (3 mm s^-1) were then applied o­n each apple to reach a strain equal to 10% (first samplings) or 5% (samplings at harvest) of the fruit diameter. This stress was applied with a texture analyser (TA.XT.Plus) fitted with a circular flat probe (5 cm f). o­ne hour after compression, a second spectrum was recorded o­n the same face.

Discriminant analysis (FDA) with cross validation procedure were applied o­n the spectral collections. In most of the cases, these analysis have shown good discriminations between apples before and after compression. Nevertheless, the capacity of NIR spectroscopy to detect bruised apples has been variable according the variety and the stage of development. The spectral absorption bands which played a major role in the discriminations were defined. The relations between the evolution of spectra after the compression and the energy absorbed during this compression were studied.