No abstract

Feruloylated arabinoxylans are the major non-starch polysaccharides from the cereal cell walls. Depending on the source, arabinoxylans exhibit different molecular features, which are determinants for their functional properties. Feruloylated arabinoxylans are of considerable importance in cereal process such as bread making and brewing. This polysaccharide represents a significant portion of human dietary fiber intake offering nutritional benefits as soluble and insoluble fiber. The presence of ferulic acid in arabinoxylans confers them antioxidant properties. Feruloylated arabinoxylans posses a unique capacity to form covalent gels in the presence of free radical-generating agents. The gels formed present interesting characteristics as neutral odor and taste, stability to pH and electrolyte concentration changes and a macroporous structure, which give them potential applications as matrices for controlled release in food and non-food applications. In this manuscript are reviewed the chemical structure, sources and applications of feruloylated arabinoxylans and arabinoxylan gels.

-The seasonal changes in the flavors and textures (sensorial and rheological traits) of young Mexican Chihuahua cheese made with either raw or pasteurized bovine milk (RM or PM, respectively) were determined to identify factors that contribute to the variability in the traditional flavors and textures of the cheese. Four selected brands of Chihuahua cheese from northern Mexico were obtained within days of manufacture during the winter, spring, and summer seasons and stored at 4• C until evaluated; at day 10 for rheology and between days 14 to 18 for sensory. Descriptive analyses of flavors and textures were conducted with panelists trained to a universal or productspecific Spectrum TM intensity scale, respectively. Microbial analyses were conducted prior to testing to ensure product safety. Rheological properties were measured using texture profile, small amplitude oscillatory shear, and torsion analyses. Results showed that the most prominent attributes in the young cheeses were: salty, sour, diacetyl, cooked, whey, bitter, and milkfat flavors with RM cheeses having more intense sour and bitter notes compared to the PM cheeses. Many cheese texture attributes were similar, but RM cheeses were perceived as softer than the PM cheeses. Rheological results supported that the RM cheeses were softer and their properties more variable than the PM cheeses. Seasonal differences were within expected brand-to-brand variation although RM cheeses had more variability than the PM cheeses. Only a few significant correlations were found among the rheological and the sensorial texture attributes which indicated that they evaluated cheese texture in different ways. As the demand for Hispanic-style cheeses increases, defining and understanding the sensorial and rheological attributes of traditionally made Mexican cheeses provides guidance to the cheese manufacturers as new ways are explored to manufacture the pasteurized version of the cheese. 分别于冬季、春节和夏季生产的当天采样, 4• C 贮藏备用;在第 10 天分析样品的流变性,Résumé -Effet de la pasteurisation et de la saison sur les caractéristiques sensorielles et rhéo-logiques du fromage mexicain Queso Chihuahua. Les changements saisonniers de flaveur et de texture du fromage mexicain Queso Chihuahua à l'état jeune, produit à partir de lait de vache cru (RM) ou pasteurisé (PM), ont été déterminés pour identifier les facteurs qui contribuent à la variabilité dans les flaveurs et textures traditionnelles du fromage. Des fromages Queso Chihuahua de quatre marques sélectionnées du nord du Mexique ont été obtenus dans les premiers jours de fabrication au cours de l'hiver, du printemps et de l'été, et stockés à 4• C jusqu'à leur évaluation, au 10 e jour pour la rhéologie et entre les 14 e et 18 e jours pour l'analyse sensorielle. Les analyses descriptives des flaveurs et textures ont été conduites avec un jury entraîné à une échelle d'intensité soit universelle, soit spécifique de produit Spectrum TM . Des analyses microbiologiques ont été effectuées avant évaluation pour assurer la sécurité du produit. Les pro...

Biosynthesis of volatile compounds (VC), as well as activity of related enzymes (lipoxygenase LOX, alcohol acyltransferase AAT, and alcohol dehydrogenase ADH), and fatty acids (palmitic, stearic, oleic, linoleic and linolenic acids) were assessed in Golden Delicious fruit apples (Malus domestica Borkh.) during 1 ºC storage at different atmosphere conditions. Three atmosphere conditions were used: 21 % O2 and > 1 % CO2 (Regular Atmosphere, RA), 3 % CO2 and 2 % O2 (Controlled Atmosphere, CA), and CA, with 7 d under RA conditions (CA + RA), to evaluate the effect of shorts periods under air storage. CA conditions inhibited the production of butyl acetate and hexyl acetate esters, and increased hexanol concentration. Production of the branched ester 2-methyl butyl acetate did not decrease under CA conditions. As a result of 7 d under RA, butyl acetate and hexyl acetate in CA + RA increased, mainly after one month of storage. Storage under CA conditions inhibited LOX and AAT activity at some stages whereas ADH activity increased during CA storage. LOX activity showed high correlation with production of aldehydes (r2 = 0.85) and cis-2-hexenal (r2 = 0.94), during storage of apples under CA conditions. Good correlation was found between AAT activity and total esters and butyl acetate content under CA storage of apples (r2 = 0.92 and r2 = 0.93, respectively). While most fatty acids increased in concentration during RA and CA storage, linolenic acid content decreased. No correlation between volatile compounds content and fatty acid production was found.

Three Candida oleophila strains (L06, L07 smooth, and L07 rough) were evaluated in vivo and in vitro as biocontrol agents against Penicillium expansum on postharvest 'Golden Delicious' apples (Malus domestica Borkh.) in Chihuahua, Mexico. The in vivo and in vitro activity of exo-β-1,3-glucanase was measured as a possible biocontrol mode of action for C. oleophila. Mean disease incidence caused by P. expansum was 0.3% for apples treated with fludioxonil + ciprodinil, which were used as a positive control, and 1% for fruits treated with a combination of the three C. oleophila strains; the effects of these treatments were significantly equivalent. Disease incidence in control apples was 39% and was significantly different from the other treatments. The in vivo exo-β-1,3-glucanase activity began at 24 h and peaked at 72 and 96 h for all treatments. Strain L06 had the highest activity (7.96 nKat) and a specific activity of 2.92 nKat μg -1 . Candida albicans had the lowest activity (2.83 nKat) and a specific activity of 0.67 nKat μg -1 . The highest in vitro activity was for C. albicans (85.03 nKat) and the lowest for strain L06 (78.2 nKat). Significant differences in both in vivo and in vitro enzymatic activity were observed between strain L06 and C. albicans. Polynomial regression analysis (R 2 = 0.96 in vitro and 0.68 in vivo) indicated that increased enzymatic activity was associated with reduced fruit disease incidence. The production of exo-β-1,3-glucanase by C. oleophila is a possible mode of action for the efficient biocontrol of P. expansum on postharvest apples.