Analysis of Lycopene Content Predict Maturity of Tomato Using NIR Spectroscopy
Date Issued
2009
Date
2009
Author(s)
Liao, Hsin-Kai
Abstract
The criterion for the fruit harvesting depends on the maturity of the fruit, blight and infection. The experiences of farmers based on the appearance of the fruit and the intuition of them are usually employed to evaluate the harvesting time for fruits. Near infrared spectroscopy, a non-destructive and rapid measurement, was used to inspect the fruit internal quality with complete spectrum information in recent years. The lycopene content of tomato (Lycopericon esculentum) was measured using near infrared spectroscopy to serve as an index of the degree of tomato maturity. Therefore, both the lycopene content and the appearance images of tomatoes can be integrated as the indices to evaluate the degree of tomato maturity for the automatic fruit harvesting system to assure the accuracy of the determination for the maturity. The color images of tomatoes were acquired by the machine vision and converted the RGB values to L*a*b* color system. The subjective judgement by farmers could be improved using the index, a*/b*, to evaluate the degree of tomato maturity. The lycopene content of the tomato was determined by measuring the extraction of tomato juice using FOSS NIRS 6500 RCA (rapid content analyzer). The calibration of lycopene content was established by the absorption of 490 nm. The standard error of estimate (SEE) was 0.216, and the coefficient of correlation (r) was 0.999. Different spectrophotometers (FOSS NIRS 6500 with fiber optics, FOSS On-Line NIRS 6500, and FOSS NIRS 6500 RCA) were used to obtain the spectra from the bottoms of intact tomatoes at the areas A, B, and C defined for different instrument attachments. The best MPLSR (multiple partial least square regression) result of the intact tomato fruit was measured using FOSS On-Line NIRS 6500 (Region C) with the first derivative pre-treatment in visible region, and rc = 0.960, SEC (standard error of calibration) = 0.53 ppm. The best MPLSR result of the spectra measured by FOSS NIRS 6500 with fiber optics (Region A) was rc = 0.918 and SEC = 0.76 ppm in the near infrared region. In summary, the rapid, non-destructive inspection with excellent prediction was successfully established in determining of the degree of maturity during the fruit harvesting.
Subjects
Near Infrared
Spectra
Tomato
Degree of Maturity
Lycopene
Type
thesis
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