Study of moisture content and water activity of rice using fluorescence spectroscopy and multivariate analysis.

The potential of fluorescence spectroscopy for non-destructive and rapid measurement of moisture content (MC) and water activity (a) of rice was examined. A total of n = 15 samples of rice produced at different locations were studied. The emission fluorescence spectra of tryptophan (305-600 nm, excitation: 290 nm) and emission fluorescence spectra of riboflavin (410-700 nm, excitation: 370 nm) were collected from milled rice.

Front-face fluorescence spectroscopy allows the characterization of mild heat treatments applied to milk. Relations with the denaturation of milk proteins.

Emission and excitation spectra of intrinsic fluorophores present in milk were used to evaluate changes in milk following thermal treatments in the 57-72 degrees C temperature range from 0.5 min up to 30 min. Alternatively, the concentrations of native alkaline phosphatase, lactoferrin, immunoglobulin G, bovine serum albumin, beta-lactoglobulin, and alpha-lactalbumin were determined in the same samples by enzymatic and immunochemical techniques.