Cıldızay ÖZBEKOVA | Asılbek KULMIRZAYEV

Article | 2023 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy306

Gluteus medius, Longissimus thoracis, and Semitendinosus muscles from the cow and yak (Bos grunniens) reared in the Kyrgyz Republic were dried by convective (hot air) drying and freeze drying. The dried muscles were grinded into fine powders and along with raw muscles were evaluated for water activity (aW), chemical composition (moisture, fat, protein), colour characteristics (L, a, and b values), fluorescence of intrinsic fluorophores (tryptophan, vitamin A, and riboflavin). Processing of measured data tables using common components and specific weights analysis (CCSWA) showed close relations among the chemical, colour, and fluores . . .cence data. CCSWA discriminated muscles depending on chemical composition, animal type, and drying technique applied based on the chemical properties, colour characteristics, and fluorescence spectra. The freeze drying was approved as a preferable dehydration technique comparing with convective drying as the one causing less discoloration to meat. Partial Least Squares Regression (PLSR) models developed using fluorescence spectra allowed accurate quantitative predicting of water activity (aW), moisture, fat, and protein contents, and colour characteristics (L, a, and b values). Keyword: chemical properties; colour characteristics; drying; fluorescence; meat powder; multivariate analysi More less

Cıldızay ÖZBEKOVA | Asılbek KULMIRZAYEV

Article | 2019 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy223

The potential of fluorescence spectroscopy for non-destructive and rapid measurement of moisture content (MC) and water activity (a(W)) 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. MC and a(W) of the rice samples were measured. Spectral data were subjected to principal component analysis (PCA) and partial least squares discriminant analysis (PLSDA). PCA and PLSDA showed the rice samples . . .can be differentiated according to their MC and geographical origin of cultivation. Partial least squares regression (PLSR) models obtained from tryptophan emission spectra predicted MC and a(W) with R-2 = 0.82 and RMSEV = 0.427, and R-2 = 0.74 and RMSEV = 0.512, respectively. PLSR models obtained using riboflavin emission spectra allowed predicting MC a(W) with R-2 = 0.85 and RMSEV = 0393, and R-2 = 0.79 and RMSEV = 0.463, respectively. This study demonstrates that fluorescence spectroscopy combined with multivariate statistical tools has promising potential for non-destructive and rapid measurement of moisture content and water activity of rice. (C) 2019 Elsevier B.V. All rights reserved More less