Madera-Santana T.J.,Research Center en Alimentos y Desarrollo |
Soto Valdez H.,Research Center en Alimentos y Desarrollo |
Richardson M.O.W.,University of Portsmouth
Polymer Engineering and Science | Year: 2013
Natural fibers (NFs) are rich in cellulose and also they are a low cost, easily renewable source for polymer composites. However, the presence of impurities (waxes, lignin, etc.) and hydroxyl groups produce those NFs with less ability to reinforce polymeric matrices. Short sisal fibers (SSF) were subjected to three different chemical treatments (alkaline, dicumyl peroxide, and silane). Composites of ethylene vinyl acetate (EVA) and chemically modified SSF were prepared by mechanical mixing at the melt state of the polymer matrix (130°C) using a two roll mill. The influences of fiber content and chemical treatment on the mechanical properties of the composites were evaluated. The tensile strength increased for every such treated SSF-reinforced composite. There was also a noticeable increase in elastic modulus compared with the unfilled matrix. The elongation at break values decreased as the fiber content was increased. Moreover, it was observed that the surface treatment of the SSF improved the fiber dispersion within the EVA matrix. The thermal stability of SSF was analyzed by thermogravimetic analysis. Potentially, the recyclability of the composites might be promising due to the lower specific gravity of NF, accompanied by low cost, and with the added advantage of biodegradability. © 2012 Society of Plastics Engineers.
Cornejo-Ramirez Y.I.,Grupo Mexico |
Cornejo-Ramirez Y.I.,University of Sonora |
Ramirez-Reyes F.,Grupo Mexico |
Ramirez-Reyes F.,University of Sonora |
And 15 more authors.
Cereal Chemistry | Year: 2016
The present work was carried out to make a comparison between the starch debranching enzyme activity and the synthesis of total carbohydrates, starch, amylose, and amylopectin in developing kernels of two sets of triticales differing in genome composition (complete and substituted triticales). The results showed that the carbohydrate and starch accumulation observed in both genotypes of triticales increased rapidly at the early stage, reaching the maximum at the medium stage and decreasing slightly or remaining relatively constant at the last stage of kernel development. At the end of the development stage, the mature grains of complete and substituted triticales accumulated 62.5 and 54.6% starch, respectively. Both sets of triticales showed the same amylose accumulation profile as well as degree of polymerization; however, at the maturity stage there was a small but significant difference between the two sets. The final polymerization values of amylose chains in mature seeds of complete and substituted triticales were DP 1,549 and 1,313. A and B1 amylopectin chains of the complete triticales were approximately 19 and 33% shorter than those of the substituted triticales. The complete triticales showed higher isoamylase and pullulanase activities than the substituted triticales, which coincided with the highest starch and amylose contents observed in kernels under development. The results of this study demonstrate that the synthesis of starch differs between the triticale genotypes used in the study, which influences their chemical structure and physicochemical properties. © 2016 AACC International, Inc.
Guevara-Arauza J.C.,Autonomous University of San Luis Potosi |
Ornelas Paz J.D.J.,Research Center en Alimentos y Desarrollo |
Mendoza S.R.,Autonomous University of San Luis Potosi |
Guerra R.E.S.,Autonomous University of San Luis Potosi |
And 2 more authors.
Chemistry Central Journal | Year: 2011
Background: Prickly pear cactus stem (nopal) has been used in folk medicine and a raw material since ancient times. Stems have been proved to possess components with valuable biological activities: anti inflamatory, antioxidant, antiulcerogenic, hypoglycemic, and so forth. Nowadays, people consume foods not only to cover the nutritional requirements, they also demand for healty, natural and convenient foods that show biological activity. This study evaluated the bio-functional effects of consuming tortillas or bars (filled with prickly pear fruit jam) supplemented or not with nopal dietary fiber.Results: The addition of nopal increased the fiber and polyphenols content in both tortillas (16.67%, 2.33 mg QE/L) and bars (13.79%, 1.99 mg QE/L). Furthermore the trolox equivalent antioxidant capacity (TEAC, 1.47 mmol/L), polyphenols (7.67 mg QE/L) and vitamin C (77.91 μmol/L) showed increased levels in volunteer's plasma after intake. Also lower levels of glucose (4.43 mmol/L), total cholesterol (4.27 mmol/L), LDL (1.96 mmol/L) and triglycerides (1.54 mmol/L) were observed in plasma after the supplementation scheme with nopal-based tortilla, while GSH:GSSG ratio in erythrocytes was higher.Conclusions: The results suggested that the intake of nopal-based tortillas with high content in fiber and antioxidant compounds can help to improve the overall oxidative status in healthy humans, which can reduce the risk of some chronic diseases. In addition, these products showed suitable physicochemical characteristics to be marketed. © 2011 Arauza et al.
Espinoza Acosta J.L.,University of Sonora |
Torres Chavez P.I.,University of Sonora |
Ramirez-Wong B.,University of Sonora |
Bello-Perez L.A.,National Polytechnic Institute of Mexico |
And 4 more authors.
Starch/Staerke | Year: 2015
Lignin conveys several important and useful characteristics to starch films depending on the lignin MW, extraction procedure, and lignin botanical source. In this study, lignin was obtained from durum wheat straw through the organosolv process, followed by fractionation according to solubility in alcohol. The alcohol-soluble lignin (ASL) was then used to prepare starch-ASL films. The mechanical properties, thermal stability, water solubility, color, and antioxidant activity of the resulting films were evaluated, and the starch-ASL films were also analyzed by means of SEM and attenuated total reflection infrared spectroscopy (ATR-IR). A procedure, to incorporate ASL, was developed and used to produce homogenous surfaces in starch-ASL films; agglomerations or undissolved particles of lignin were not observed in the starch matrix at microscopic level. ASL promoted significant decrease of the tensile strength (TS) and elastic modulus (EM), but an increase of elongation at break (EB) in films. Thermal analysis of the starch-ASL films showed high resistance to thermal degradation, due to the incorporation of ASL. In addition, the starch-ASL films exhibited antioxidant activity (2,2-diphenyl-1-picrylhydrazyl [DPPH]), which increased with increasing ASL content. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.