Attenuated total reflectance-Fourier transform infrared (ATR–FTIR) spectroscopy and multivariate analysis were used to study honey intentionally adulterated with standard sugar solutions (glucose, fructose and sucrose), and also with cheap syrups (corn, inverted and cane sugar). By using the principal component analysis (PCA) method on pure and adulterated (0–100%) honey samples, the determination of the type of adulterant was realized in an easy way through the use of the two- and three-dimensional PCA score plots. From this analysis, a tetrahedral structure was obtained. Superior vertex is formed by the set of samples of pure honey, whereas the edges are formed by the adulterant sugars. Partial least squares method was employed to develop optimal calibrations for the six adulterants used, obtaining values of standard error of calibration in the range 0.377–0.583 and standard error of prediction in the range of 1.550–3.150 for the standard sugars, which suggest a good predictive capacity of the model employed in this study.

Some of the greatest challenges in stem cells (SCs) biology and regenerative medicine are differentiation control of SCs and ensuring the purity of differentiated cells. In this work, we differentiated mouse pluripotent stem cells (mPSCs) toward pancreatic cells characterizing this differentiation process by molecular and spectroscopic technics. Both mPSCs and Differentiated Pancreatic Cells (DPCs) were subjected to a genetic, phenotypic, and biochemical analysis by real‐time quantitative PCR (RT‐qPCR), immunocytochemistry, and Fourier Transform Infrared (FTIR) spectroscopy. Cultured mPCSs expressed pluripotent genes and proteins (Nanog and SOX2). DPCs expressed endodermal genes (SOX17 and Pdx1) at day 11, an inductor gene of embryonic pancreas development (Pdx1) at day 17 and pancreas genes and proteins (Insulin and Glucagon) at day 21 of differentiation. Likewise, FTIR spectra of mPSCs and DPCs at different maturation stages (11, 17, and 21 days) were obtained and showed absorption bands related with different types of biomolecules. These FTIR spectra exhibited significant spectral changes agreeing with the differentiation process, particularly in proteins and nucleic acids bands. In conclusion, the obtained DPCs passed through the chronological stages of embryonic pancreas development and FTIR spectra provide a new biophysical parameter based on molecular markers indicating the differentiation process of mPSCs to specialized cells.

Chia (Salvia hispanica L.) seeds contain antioxidants with great benefits for health and are widely used in the food industry. Antioxidants can be degraded by environmental factors, decreasing their biological activity. Their encapsulation in chitosan (CH) particles represents an alternative to protect them and increases their application. The encapsulation efficiency (EE) of the antioxidants in the CH particles depends on the synthesis conditions. In this study, two methods for encapsulation of chia extract in chitosan particles were evaluated: method A, 0.05 CH in 1 acetic acid was mixed with 0.07 of tripolyphosphate (TPP) and method B, 0.3 CH in 2 acetic acid was mixed with 1 TPP. The results showed that the EE decreased with the concentration of the extract, and the FTIR analysis suggested that the compounds of the extract were adsorbed on the surface of the particles. Dynamic light scattering and zeta potential analysis showed that the particles of method A are unstable and with a tendency to agglomerate, and the particles of method B are stable. The highest EE was obtained with 0.2mg·mL⁻¹ (method A) and 1.0mg·mL⁻¹ (method B) of the extract. The higher loading capacity (LC) (1672) was exhibited by the particles of method A. The best particle yield (6269) was observed for method B. The particles with the extract adsorbed showed antioxidant activity (560) at 25°C; however, in the particles with the extract encapsulated, the activity increased after subjecting to acidic conditions at 40°C due to the breakdown of the particles. The results obtained will allow choosing the appropriate conditions for the synthesis of chitosan particles loaded with chia extracts with specific characteristics (EE, LC, size, and type) according to their future applications. The particles could be used in food and pharmaceutical industries and even in edible films for food packaging.

An easily prepared fluorescent bioconjugate colloidal solution based on gold nanoparticles is reported for the detection of Salmonella. This bioconjugate was prepared by conjugation of staphylococcal protein A on the surface of gold nanoparticles, followed by biofunctionalization over this layer with fluorescein isothiocyanate-labeled antibodies. The surface plasmon resonance band observed in the ultraviolet–visible spectrum of the gold nanoparticles showed a shift to low energy after covering the surface with protein A and a broadening of the band after biofunctionalization with the antibody. Surface-enhanced infrared spectroscopy showed the absorption bands of the conjugate and bioconjugate due to their proximity to the nanoparticles. In particular, vibrations at 1649, 1588, and 1400 cm⁻¹ were from C˭O, N–H, and C–NH₂ groups from the staphylococcal protein A covering the gold nanoparticles. The final bioconjugate colloidal solution was also used as probe to detecting Salmonella by confocal microscopy of solutions containing 1E3 and 1E5 CFU/ml. The total time required to detect these bacteria was less than 1 h. Fluorescent emission of the bacillus suggests that this methodology may have potential to develop a universal method for detecting different bacteria.