Optical evaluation of factors affecting appearance of bovine fat

Factors affecting the appearance of bovine fat were studied with a spectrophotometer using surface and transmittance optical probes and halogen and mercury lamps. Reflectance minima in the spectra of the fat were mainly derived from β-carotene and hemoglobin. The presence of deoxy- and met-hemoglobin darkened the fat color. There were wide differences in the transmittance measurements among the white colored fats. The extracted lipid had a lower reflectance than the adipose tissue but the grinding fat had higher reflectance. With ultraviolet light, the adipose tissue had a higher fluorescence, which strengthened the perceived whiteness compared to the extracted lipid. These results showed that the appearance of bovine fat is mainly affected by the absorbance of carotene and hemoglobin derivatives, the reflectance, transmittance, and fluorescence of lipids, and the reflectance and fluorescence of non-lipid components (connective tissue and cell membranes).