María del Mar Cavia

Evolution of fructose and glucose in honey over one year: influence of induced granulation

Abstract Evolution of fructose and glucose over 1 year has been evaluated in 30 honey samples from Burgos (N. Spain). The influence of the induced granulation process in this evolution was also determined. Each sample was divided into two aliquots of 500 g and aseptically bottled. One aliquot was directly stored and the second induced to crystallise by seeding with 10% of finely crystallised honey. Analyses of moisture content, pH, fructose and glucose were carried out over 1 year, once each 4 months. Both, fructose and glucose increased in most samples. Induced-crystallised samples did not show any significant differences in the evolution of the two sugars in comparsion with directly stored samples. Linear correlations were found, for both fructose and glucose, between samples directly stored and honeys in which granulation was induced. These results are clearly different from those reported in previous papers where decrease of monosaccharides below their original values was described. pH of honey might promote reversion of monosaccharides and the formation of disaccharides and trisaccharides. This investigation has demonstrated the possibility of formation of monosaccharides, by the hydrolysis of higher sugars, as a process predominant over the reversion. No statistical relationship was found between pH of honey samples and their fructose and glucose content evolution.

Diacylglycerol-containing oleic acid induces increases in [Ca(2+)](i) via TRPC3/6 channels in human T-cells.

Though most of the studies have focused on the effects of free fatty acids on T-cell activation, fatty acids incorporated into plasma membrane phospholipids may also affect cell signaling via diacylglycerol (DAG), generally produced by phospholipid hydrolysis. In the present study, we have synthesized a DAG-containing oleic acid and studied its implication in the modulation of calcium signaling in human Jurkat T-cells. 1-palmitoyl-2-oleoyl-sn-glycerol (POG) induced a dose-dependent increase in [Ca(2+)](i). This effect was due to the presence of oleic acid at the sn-2 position as no differences were observed between POG and 1-stearoly-2-oleoyl-sn-glycerol (SOG). However, the substitution of oleic acid with arachidonic acid at the sn-2 position of the DAG moiety exerted a different response on the increases in [Ca(2+)](i) in these cells. POG-evoked increases in [Ca(2+)](i) were not due to its metabolites. Furthermore, POG-induced increases in [Ca(2+)](i) were due to the opening of TRPC3/TRPC6 channels as silencing of TRPC3 and TRPC6 genes by shRNA abolished calcium entry. Moreover, disruption of lipid rafts with methyl-β-cyclodextrin completely abolished POG-evoked increases in [Ca(2+)](i). In conclusion, our results demonstrate that oleic acid can influence T-lymphocyte functions, in the conjugated form of DAG, via opening TRPC3/6 channels.

GLOBAL ANTIOXIDANT RESPONSE OF MEAT

BACKGROUND The global antioxidant response (GAR) method uses an enzymatic digestion to release antioxidants from foods. Owing to the importance of digestion for protein breakdown and subsequent release of bioactive compounds, the aim of the present study was to compare the GAR method for meat with the existing methodologies: the extraction-based method and QUENCHER. Seven fresh meats were analyzed using ABTS and FRAP assays. RESULTS Our results indicated that the GAR of meat was higher than the total antioxidant capacity (TAC) assessed with the traditional extraction-based method. When evaluated with GAR, the thermal treatment led to an increase in the TAC of the soluble fraction, contrasting with a decreased TAC after cooking measured using the extraction-based method. The effect of thermal treatment on the TAC assessed by the QUENCHER method seemed to be dependent on the assay applied, since results from ABTS differed from FRAP. CONCLUSION Our results allow us to hypothesize that the activation of latent bioactive peptides along the gastrointestinal tract should be taken into consideration when evaluating the TAC of meat. Therefore, we conclude that the GAR method may be more appropriate for assessing the TAC of meat than the existing, most commonly used methods.

Antioxidant Capacity of Beetroot: Traditional vs Novel Approaches

Red beetroot has been ranked among the 10 most potent antioxidant vegetables, although only extraction-based methods have been used to evaluate its total antioxidant capacity. Therefore, the present study aims at comparing the traditional extraction-based method with two more recent approaches (QUENCHER -QUick, Easy, New, CHEap and Reproducible- and GAR -global antioxidant response method), in order to establish their suitability in the case of beetroot. Our results indicate that the total antioxidant capacity of beetroot would be underestimated when using extraction-based procedures, since both QUENCHER and GAR methods resulted in a higher total antioxidant capacity. The effect of a thermal treatment on the total antioxidant capacity of beetroot varies among the methods evaluated and our findings suggest different compounds responsible for the total antioxidant capacity detected in each pre-processing method. Remarkably, the present study demonstrates that the traditional extraction-based method seems useful to screen for (changes in) the “bioavailable” antioxidant potential of the root.

Relación entre la composición corporal y la práctica deportiva en adolescentes

INTRODUCTION knowing precisely body composition is important in assessing the nutritional status of adolescents in order to evaluate how it affects the sport practice in this group. OBJECTIVES to evaluate the influence of regular physical exercise in a group of adolescents in their body composition. METHODOLOGY 77 male adolescents between 12 and 13 years were evaluated. Weight, height, triceps skinfold (PCT), wrist perimeter, the relaxed arm and umbilical waist were evaluated. The body fat percentage (% BF) was estimated using different equations (Siri, Siri modified, Lohman, Johnston, Deurenberg BMI, body fat percentage from ICT). Electrical bioimpedance equipment was also used. RESULTS no significant differences in BMI between the two groups were found. The prevalence of overweight and obesity varied by percentile tables used. Differences in the PCT and the percentage of body fat between groups were significants; it was higher in non-athletes (p < 0.05). No significant differences between the values of body fat were obtained by modified equations Siri, Lohman and bioimpedance, in none of the two groups studied. DISCUSSION the % BF was higher in the group of non-athletes, as well as the value of PCT to the same value of BMI. It was determined that the collective athlete got a better nutritional status than the non-athletic collective. Regardless of the method used, results should be interpreted with caution in assessing body composition of adolescents.