The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60 degrees C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins.

Homogeneous and thin porous membranes composed of oriented fibers were obtained from wheat gluten (WG) using the electrospinning technique. SEM micrographs showed an asymmetric structure and some porosity, which, in addition to a small thickness of 40 μm, are desirable characteristics for the membranes’ potential application in release systems. The membranes were loaded with urea to obtain pastilles. FT-IR and DSC studies confirmed the existence of interactions via hydrogen bonding between urea and WG proteins. The pastilles were studied as prolonged-released systems of urea in water. The release of urea during the first 10 min was very fast; then, the rate of release decreased as it reached equilibrium at 300 min, with a total of ≈98% urea released. TGA analysis showed that the release system obtained is thermally stable up to a temperature of 117 °C. It was concluded that a prolonged-release system of urea could be satisfactorily produced using WG fibers obtained by electrospinning for potential application in agricultural crops.

Cereal Chem. 84(3):207-213Wheat flours commercially produced at 74, 80, and 100% extraction rates made from hard white winter wheat (WWF) and hard red winter wheat (WRF) were used to produce tortillas at a commercial-scale level. Flour characteristics for moisture, dry gluten, protein, ash, sedimentation volume, falling number, starch damage, and particle-size distribution were obtained. Farinograms and alveograms were also obtained for flourwater dough. A typical northern Mexican formula was used in the laboratory to test the tortilla-making properties of the flours. Then commercialscale tortilla-baking trials were run on each flour. The baked tortillas were stored at room and refrigeration temperatures for 0, 1, 2, and 3 days. Maximum stress and rollability were measured every day. Tortilla moisture, color, diameter, weight, and thickness were measured for each treatment.Finally, tortilla acceptability was tested by an untrained sensory panel. Analyses of variance (ANOVA) were performed on the data. WWF had higher protein content, dry gluten, sedimentation volume, and water absorption than the WRF. The WWF was the strongest flour based on farinograph development time and alveograph deformation work. It also produced the most extensible dough measured with the alveograph (P/L). Flour protein and ash contents, water absorption, and tenacity increased directly with the flour extraction rate. Both WWF and WRF performed well in commercial-scale baking trials of tortillas. Tortillas made with both types of flours at 74 and 80% extraction rates had the best firmness and rollability. However, tortillas made with WWF 80% had the best color (highest L value). Tortillas prepared with 100% extraction rate flour were also well accepted by the sensory panel, had good textural characteristics, and became only slightly firm and slightly less rollable after three days of storage at room temperature.

Sorghum bran components could be a potential source of nutrients and phytochemicals for industrial applications. The effect of defatting with hexane and different degrees of decortication on distribution of fatty acids, phenolic compounds, colour (L, a and b) and antioxidant activity (DPPH) of red (RS) and white (WS) sorghums was studied. The decortication process was carried out at time intervals of 1-6 min. Defatted and nondefatted fractions were analysed. The content of polyunsaturated fatty acids (PUFA) was higher than monounsaturated fatty acids (MUFA); the content of MUFA was higher than saturated fatty acids (SFA). Linoleic, oleic and palmitic acids predominated in all fractions. Significant differences in the content of palmitic and linolenic acids between sorghums were found. RS had higher content of palmitic, and WS was higher in linoleic acid. Defatted samples contained lower amounts of phenolic compounds and higher antioxidant activities, than nondefatted samples. RS was a better source of total phenolic compounds and antioxidant activity compared with WS, but WS presented a more suitable profile of fatty acids. In conclusion, fractions of both types of sorghums can be used in cereal-based products to enhance their phytochemical profile.

No abstract

Our work shows that the irradiation procedure leads to an increase in the number and size of nanovesicles along with the dose. The functionality of RBC can be affected from changes in the roughness, becoming more fragile and susceptible to breakage.

No abstract

Chitin neoglycoconjugates (BSA-CO) were obtained by the conjugation of bovine serum albumin (BSA) with chitin oligosaccharides (CO) through the Maillard reaction (nonenzymatic glycation). CO produced by acid hydrolysis of chitin were fractionated using an ultrafiltration membrane system (1-3 kDa cutoff). The Maillard reaction was carried out by heating a freeze-dried mixture containing BSA and CO at 60 °C (under 43% relative humidity for 6 and 12 h). BSA-CO were characterized by available amino groups content, intrinsic tryptophan emission spectra, gel electrophoresis, and mass spectrometry. Biological assays included interaction with wheat germ agglutinin (WGA) and with bacterial adhesins of Escherichia coli K88+ and Salmonella choleraesuis. Glycation of BSA was revealed by reduction of available amino groups and fluorescence intensity and also retarded migration through SDS-PAGE. Conjugation of BSA with chitin oligomers appeared to be time dependent and was confirmed by mass spectrometry, by which molecular mass increase for monomers and dimers was observed. Monomers were estimated to contain either one or two glycation sites (at 6 and 12 h of treatment, respectively), with one or two tetrasaccharide units attached. Consequently, dimers showed two or four glycation sites. BSA-CO presented biological recognition by WGA and E. coli K88+ and S. cholerasuis adhesins. The strategy used in this work represents a simple method to obtain glycoconjugates to study applications involving protein-carbohydrate recognition.