Rapid quantification models for assessing melamine adulteration in sport nutrition supplements via benchtop and portable NIRS instruments.

Sport nutrition supplements (SNS) are vulnerable to adulteration with melamine, artificially augmenting their protein content as determined by conventional assay methodologies. Vibrational spectroscopy techniques are suitable for the detection of adulteration because they allow rapid analysis, require minimal sample preparation, and can perform numerous analyses in a short time. The aim of this study was to develop rapid quantification models for the determination of melamine adulteration in a variety of SNS matrices using NIRS (near-infrared spectroscopy) in combination with multivariate data processing. Moreover, a comparison of benchtop and portable NIR instruments was carried out. Employing a stepwise approach involving OPLS-DA and PLS analysis, matrix discrimination and prediction ability were investigated. The benchtop instrument effectively discriminated among matrices (R2Y = 0.964, Q2 = 0.933), while the portable device, although showing a slightly altered pattern, maintained favorable discrimination capability (R2Y = 0.966, Q2 = 0.931). The quantitative PLS models for each SNS matrix exhibited comparable statistical indicators for both instruments with reasonable errors for melamine content estimation and prediction (RMSEE: 0.3-2.4 %, RMSEP: 0.98-2.99 %). Higher estimation and prediction errors were observed for protein-containing samples in both acquisition modes, probably due to the tendency of protein agglomeration and adhesion to different surfaces, which affects the homogeneity of the powder. Despite data loss due to the narrower spectral range and lower resolution of the portable instrument, all models were found to be suitable for predicting melamine content in sport nutrition supplements.

Optimization of the formulation for preparing Lactobacillus casei loaded whey protein-Ca-alginate microparticles using full-factorial design.

CONTEXT: This article presents specific approach for microencapsulation of Lactobacillus casei using emulsion method followed by additional coating with whey protein. METHODS: Experimental design was employed using polynomial regression model at 2nd level with three independent variables, concentrations of alginate, whey protein and CaCl2. Physicochemical, biopharmaceutical and biological properties were investigated. RESULTS: In 11 series generated, negatively charged microparticles were obtained, with size 6.99-9.88 µm, Ca-content 0.29-0.47 mg per 10 mg microparticles, and viability of the probiotic 9.30-10.87 log10CFU/g. The viability after 24 hours in simulated gastrointestinal conditions was between 3.60 and 8.32 log10CFU/g. DISCUSSION: Optimal formulation of the microparticles that ensures survival of the probiotic and achieves controlled delivery was determined: 2.5% (w/w) alginate, 3% (w/w) CaCl2 and 3% (w/w) whey protein. CONCLUSION: The advantageous properties of the L. casei-loaded microparticles make them suitable for incorporation in functional food and/or pharmaceutical products.