This paper presents a nondestructive method for evaluating changes in the moisture content and in the interaction between contents such as protein and water molecule in beef cut by using visible and near infrared spectroscopies. Spectral variations in the 450-1100 nm region were measured for a beef cut using two types of spectrometers. Bands were observed in the 540-570, 600-660 and 920-980 nm regions according to the change in moisture contents. The PLS regression of moisture contents by using the second derivative in the 920-980 nm region provided a very good predictive model with R2 = 0.96 and RMSE = 0.04. Moreover a band in the 600-660 nm shifted to longer wavelength in the 0.9-1.0 of water activity range and then this band slightly shifted to shorter wavelength in the lower water activity range. This spectral behavior may reflect the appearance and oxidation of myoglobin due to dry in/on beef. Simultaneously, it is very likely that the behavior of each water state; free and bonded can describe well by that band shift. These results obtained therefore provide a fundamental chemical understanding of band behavior in the 600-660 nm region and suggested that one can evaluate the quality degradation in beef cut by using visible and NIR spectral region.
- Band shift
- Moisture content
- PLS regression
- Visible and near infrared spectroscopy
- Water activity