| Abstract: | ABSTRACT: Frozen fish usually have a much lower market price than fresh fish; therefore, adulteration could occur. This article focuses on the use of near infrared (NIR) spectroscopy to detect whether fish has been frozen‐thawed because NIR spectroscopy has demonstrated the potential for addressing some authenticity issue in foods and is known to be a nondestructive rapid technique. Horse mackerel (n = 162) were evaluated as fresh and frozen‐thawed fish sample. Dry extract spectroscopy by infrared reflection (DESIR) of fresh and frozen‐thawed fish samples was performed on the meat juices then discriminated by principal component analysis (PCA) and multiple linear regressions (MLR). In DESIR spectra, the overall absorbance level was found to decrease in frozen‐thawed samples, indicating the different chemical composition of juice, amount of dry matter, particle size, and their scattering properties. The spectral changes that take place between fresh and frozen‐thawed samples are clearly seen in the 1920‐ to 2350‐nm region. The spectra are dominated by peaks attributed to proteins, in particular, peaks at 1510, 1700, 1738, 2056, 2176, 2298, and 2346 nm. It was found that fresh and frozen‐thawed fish could be separated 100% correctly by DESIR technique. |
