2021 Volume 38 Issue 3 Pages 235-
Evaluating the thawing level of frozen ingredients in food manufacturing processes is important for ensuring quality. In the present study, a new approach for measuring the ice fraction, an indicator of the thawing level of frozen foods, was developed using near-infrared (NIR) spectroscopy. In the NIR spectra (700–1100 nm), the OH band shifted to shorter wavelengths as the ice fraction decreased. Savitzky-Golay second-derivative treatment revealed that the peak intensity of ice decreased whereas that of water increased as the ice fraction decreased. Multiple linear regression models constructed using the second-derivative spectra provided prediction values that agreed well (determination coefficients of 0.96 for agar and 0.84 for pork) with the ice fractions determined using conventional calorimetry (0–71.6 % for agar and 0.3–67.4 % for pork). Thus, this NIR technique can be applied as a non-destructive and rapid method for confirming the thawing level of frozen foods.
