Changes in color and phenolic compounds during the raisining of grape cv. Pedro Ximenez

Changes in color parameters and phenolic compounds during the sun-drying grape raisining of cv. Pedro Ximenez to obtain sweet wines are studied. Browning increases during the process as a result of the contribution to a greater extent of the low and medium molecular size polymers than the high molecular size polymers. Raisining decreases hue and lightness and increases chroma, all measured as CIELab parameters, indicating a color change to dark reddish hues that is also preferentially due to low and medium molecular size polymers. Most of the phenols studied increase in concentration during raisining, essentially through the concentration effect resulting from the loss of water in the grapes. The concentration changes, however, are comparatively small for hydroxycinnamic esters and flavan-3-ol derivatives, suggesting that these phenolic fractions undergo predominantly oxidative degradation reactions by enzymatic pathways, contributing strongly to the browning of grapes.     

Effect of a preparation of Saccharomyces cerevisiae on microbial profiles and fermentation patterns in the large intestine of horses fed a high fiber or a high starch diet

Eight horses were allotted into pairs consisting of one cecum- and right ventral colon-fistulated animal and one cecum-fistulated animal. They were fed daily at the same level of intake either a high-fiber (HF) or a high-starch (HS) diet without or with 10 g of a Saccharomyces cerevisiae preparation, in a 4 x 4 Latin square design. The HS diet provided a starch overload (i.e., 3.4 g starch x kg(-1) BW x meal(-1)) while maintaining a high amount of fiber intake (i.e., dietary NDF/starch ratio was 1.0). A 21-d period of adaptation to the treatments occurred before cecal and colonic contents were withdrawn 4 h after the morning meal to count total anaerobic, cellulolytic, and lactic acid-utilizing bacteria, lactobacilli, and streptococci. Lactic acid, volatile fatty acids, ammonia concentrations, and pH were measured on cecal and colonic fluid samples collected hourly during the first 12-h postfeeding. When the HS diet was fed, the concentration of total anaerobic and lactic acid-utilizing bacteria increased (P < 0.001), whereas that of cellulolytic bacteria decreased (P < 0.05) in the cecum. The concentration of lactobacilli and streptococci increased (P < 0.001) in the cecal and colonic contents. These alterations of the microbial profiles were associated with decreases (P < 0.001) of pH, (acetate + butyrate)/propionate ratio and with an increase (P < 0.001) of lactic acid concentration. Supplementing the S. cerevisiae preparation increased (P < 0.01) the concentration of viable yeast cells, averaging 4.3 x 10(6) and 4.5 x 10(4) cfu/mL in the cecal and colonic contents, respectively. Yeast supplementation had almost no effect on microbial counts in the cecum and colon. The supplementation of S. cerevisiae appeared to modify (P < 0.05) pH, concentrations of lactic acid and ammonia, molar percentages of acetate and butyrate with the HS diet and [(acetate + butyrate)/propionate] ratio when the HF diet was fed. The effects of the S. cerevisiae preparation were greater in the cecum than in the colon, which coincided with the abundance of yeast cells. When the digestion of starch in the small intestine was saturated, the effect of the addition of a S. cerevisiae preparation appeared to limit the extent of undesirable changes in the intestinal ecosystem of the horse.     

Laboratory evaluation of natural pyrethrins, pymetrozine and triflumuron as alternatives to controlCeratitis capitata adults

Three insecticides, pyrethrins + piperonil butoxide (PBO), pymetrozine and triflumuron, were tested as potential alternatives for controlling the Mediterranean fruit flyCeratitis capitata (Wiedemann) (Diptera: Tephritidae). The compounds were administered to adult flies in the laboratory by different uptake methods at the recommended rates currently used in fruit crops in Spain. Pyrethrins + PBO (80 + 320 ppm a.i.) exhibited a comparable knock-down effect to malathion (1,500 ppm a.i.) in the laboratory, irrespective of the method of application used. After these results were obtained, the number of concentrations tested was increased to carry out a dose-response analysis. Pymetrozine (300 ppm a.i.) and triflumuron (150 ppm a.i.) did not kill adults at the concentrations tested. However, pymetrozine diminished the fecundity, especially when adults were fed the insecticide; egg hatch was decreased by 59.3% compared with controls. Further experiments showed that increased period of ingestion and higher concentrations had a clear effect in reducing both fecundity and fertility. The possible use of pyrethrins + PBO and pymetrozine to reduce populations ofC. capitata is discussed. http://www.phytoparasitica.org posting July 22, 2006. Corresponding author     

Frequency and causes of infectious abortion in a dairy herd in Queretaro, Mexico

The objective of this study was to determine the frequency of infectious bovine abortion and to identify some of its causes, specifically brucellosis, leptospirosis, bovine viral diarrhea, infectious bovine rhinotracheitis, and neosporosis. The study was carried out in a dairy herd in the state of Queretaro, Mexico, between September 2002 and March 2003. At the beginning of the study, blood samples were taken from a random 33% of the 300 lactating or pregnant cows; antibodies against Leptospira interrogans were the most commonly identified, in 91% of the 99 samples. Blood samples were also taken 14 to 28 d after the 26 subsequent abortions in the herd in the 6-mo study period, as well as from 22 cows that had not aborted within 5 d after the abortions in the other group. Seroconversion was most frequent for L. hardjo, occurring in 8 (67%) of the 12 dams that aborted after the initial serologic sampling and for which paired serum samples were therefore available. Of the 16 collected fetuses, 10 had histologic lesions suggesting infection in various organs, the features correlating with the serologic results for the dams in 7 cases. Thus, the abortions may have been caused by more than 1 infectious agent.     

Leaf optical properties in Venezuelan cloud forest trees

Leaf optical properties and related leaf characteristics were compared for thirteen cloud forest tree species differing in successional status. Sun leaves were sampled for the eight pioneer species and sun and shade leaves were sampled for the five climax species. Sun leaves had a slightly higher absorptance than shade leaves, although differences were small. Sun leaves had a higher leaf mass per unit area (LMA) and a lower chlorophyll concentration per unit leaf mass, resulting in similar chlorophyll concentrations per unit leaf area and hence similar light harvesting capacities as shade leaves. However, shade leaves realized a higher efficiency of absorptance per unit leaf biomass than sun leaves. There were few differences in leaf characteristics of sun leaves between the climax and pioneer species. Absorptance values of cloud forest species were comparable with values reported for rain forest and more seasonal forest species. Intraspecific variation in leaf absorptance was largely the result of variation in LMA, whereas interspecific variation in leaf absorptance was largely a result of variation in chlorophyll concentration per unit leaf area.     

Evaluation of protein hydrolysis in raw sources by digestive proteases of Senegalese sole (Solea senegalensis,Kaup 1858) using a combination of an in vitro assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of products

The hydrolysis of protein in different animal and plant sources by the intestinal proteases of Senegalese sole (Solea senegalensis) was studied using a combination of an in vitro digestibility assay and the evaluation of the protein fractionation by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE). In vitro hydrolysis was performed for 90 min in a closed reactor maintained at constant pH and temperature. Samples of the reaction mixture at different time intervals were developed in SDS‐PAGE gels to evaluate the progressive hydrolysis of the different protein fractions in each protein source. A numerical value [coefficient of protein degradation (CPD)], which integrates the information obtained after image analysis of the gels, is proposed for comparison among proteins, according to the intensity of the hydrolysis produced by sole proteases. Additionally, the total free amino acid released from proteins was measured during the in vitro assay. Casein, squid meal and soybean concentrate (SBC) proteins showed very similar degradation patterns, with a quick and almost complete proteolysis within the first minutes of the enzymatic reaction. Fish and krill meals were hydrolysed more progressively. On the contrary, pea meal (PM) and corn gluten meal (CGM) showed scarce changes in their protein profile after 90 min of reaction. For animal protein sources, the final CPD values ranged from 77.6% to 87.0%, showing not significant differences. By contrast, PM (30.5%) and CGM (32.3%) presented significantly lower CPD values (P<0.05) as compared with SBC (90.6%). In general, a linear fitting was found between CPD and the release of free amino acids during in vitro protein hydrolysis. The present study provides detailed information, which, combined with the conventional in vitro digestibility studies, may help in the evaluation of different raw sources according to their protein degradation patterns. This information can be applied directly to estimate the protein nutritional quality of ingredients for Senegalese sole feeds.     

Contribution of Hydrophobic Soluble Gluten Proteins,Fractionated by Hydrophobic Interaction Chromatography in Highly Acetylated Agarose,to Dough Rheological Properties

Hydrophobic interaction chromatography with highly acetylated agarose in 1‐mL columns was used to fractionate gliadins and acid‐soluble glutenins. Proteins were eluted in two fractions, the first with acetate buffer (pH 3.6) containing 35% propanol, and the second with Tris buffer in 8M urea. The proportion of eluted protein in the second fraction was called the surface hydrophobicity index. The study included 20 wheat samples of different baking qualities. Multiple regression analysis using the general linear model combined with the stepwise technique was used to relate the surface hydrophobicity index of soluble gluten proteins to specific dough rheological characteristics. Surface hydrophobicity index of gliadins and acetic acid soluble glutenins explained part of the variability of swelling index, extensibility, and work of deformation (dough strength) measured with the alveograph, and part of the farinograph water absorption variability, but showed no relationship to dough mixing characteristics. Hydrophobic soluble gluten proteins fractionated by hydrophobic interaction chromatography (HIC) explained a part of the variability of dough rheological properties.     

The Spanish barley core collection

Spanish barleys constitute a germplasm group of particular interest for breeding purposes, as Spain has been proposed as a possible centre of origin of the crop. The Spanish National Germplasm Bank (Banco Nacional de Germoplasma, BNG), holds a collection of about 2000 barley accessions, mostly landraces collected in Spain prior to extensive introduction of modern varieties. The objective of this work is to create a core collection of barleys representative of old barley genotypes grown in Spain. The core collection will be constituted by three groups of germplasm: successful old varieties (15); entries in common with previously existing barley core collections (15); and 2-row (8) and 6-row (122) entries from the BNG, for a total of 160 entries. Entries were allocated by stratified sampling in agro-ecological uniform zones of barley cultivation in Spain. Classification of agro-ecological regions for barley was based on historical yield records for Spanish provinces. The number of entries for each region was determined in proportion to the logarithm of historical barley acreage. Final choice of accessions within provinces tried to maximize the diversity and avoid duplications by looking at passport data, and to agronomic evaluation data available for a group of about 900 accessions.