1- Department of Mechanical Engineering in Agricultural Machinery, Faculty of Agriculture, Urmia
University, Urmia, Islamic Republic of Iran.
2- Department of Agricultural Machinery Engineering, Faculty of Agriculture, Tarbiat Modares University,
P. O. Box: 14115-336, Tehran, Islamic Republic of Iran.
3- Department of Molecular and Atomic Physics, Faculty of Sciences, Tarbiat Modares University, Tehran,
Islamic Republic of Iran.
Abstract: (6574 Views)
Tomato is a major fruit, as well as a major food science product. There is a need of
determining the quality attributes of this fruit (nondestructively) due to the increasing
demand of the in agro-industrially controlled areas. Most of the commonly employed
techniques are time consuming and involve a considerable degree of manual work.
Sample preparation, juice making, and laboratory tests are among the limitations. Raman
spectroscopy was applied in this study to measure such important quality parameters of
tomato as SSC, pH and color. A dispersive Raman instrument was employed and
reference analyses were carried out to make calibration models regarding the spectral
features and target attributes. Analysis of the spectra revealed that all the three
characteristic bands of cartenoids, lycopene, and carotene, were significantly
recognizable. Also there were several strong to medium bands recognized as related to
carbohydrates. Principal Component Regression (PCR) and Partial Least Square (PLS)
were selected as the multivariate calibration models. The prediction models proved to be
robust resulting in a desirable mapping between the spectra and output attributes. The
Root Mean Square Error of Predictions (RMSEP) through PLS and PCR for modeling
the color index using the whole spectrum was obtained as 0.33 and 0.38, respectively.
RMSEP for mapping the SSC using PLS and PCR models was resulted in respective
figures of 0.30 and 0.38. PCA interpretation depicted that Raman spectra could make a
favorable distinction among the samples based on their maturity stages. As a result, there
is a great potential to use Raman spectroscopy in industrial approach and in line control.
Received: 2011/02/5 | Accepted: 2011/02/5 | Published: 2011/02/5