Non-Destructive Quality Evaluation of Fruits Using Nir Spectroscopy

News sources: National Agricultural Mechanization Research Institute (NAMRI), Rural Development Administration, Suwon441-707, Korea
For further information: Annual Research Report 1999, NAMRI, 2001-03-01

Measuring Internal Quality of Fruits

The internal quality of fruits can be measured in real time and nondestructively by using visible and NIR (Near-Infrared) spectra. To estimate the soluble solid content of apples, MLR (Multiple Linear Regression), PLSR (Partial Least Square Regression), and ANN (Artificial Neural Network) models were developed. The three were compared, based on the coefficient of determination, bias and standard errors of prediction (SEP).

Grading System Based on Light Waves

A non-destructive automatic apple sweetness grading system, which consists of photodiode-array (PDA) sensors, quartz-halogen lamps, and fiber optic to transmit the light, was developed and evaluated. The MLR model, which uses wavelengths of between 800nm and 1100nm, was adopted as the best system to estimate the soluble solid content of apples.

Results of Performance Tests

The results of the performance tests of the system showed a SEP of 0.798 Brix, a bias of 0.264 Brix, and a handling capacity of 3 apples per second.

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