No abstract

Physicochemical and functional properties of a protein-rich fraction produced by dry fractionation of chia seeds (Salvia hispanica L.)Propiedades fisicoquímicas y funcionales de una fracción rica en proteína obtenida por fraccionamiento en seco de semillas de chía (Salvia hispanica L.)Alfredo Va´zquez-Ovando, David Betancur-Ancona and Luis Chel-Guerrero* Due to possible denaturation, the protein extraction method has a major impact on its functional properties in food. Dry milling and fractionation produce less protein modification and require no effluents. The physicochemical and functional properties were evaluated for Salvia hispanica L. seed protein-rich fraction (SPRF) produced by dry fractionation. This contained (g/kg) 446.2 of protein and 345.2 of nitrogen-free extract. The maximum nitrogen solubility was 60% at alkaline pH and the minimum was 11.7% at pH 4. The emulsifying activity ranged from 50 to 56% and was independent of pH. Emulsion stability was highest (92%) at pH 8 and 10. SPRF was not a good foaming agent, with a maximum of 29% and no dependence on pH. However, foam stability was good (80%). Diluted solutions (30 and 40 g/L) exhibited high apparent viscosity (10,000 cP) with typical non-Newtonian fluid behavior. The SPRF is a potential food ingredient, particularly in foods requiring emulsion or foam stability.Keywords: chia; protein fraction; foaming capacity; emulsifying capacity; solubility; apparent viscosity El me´todo de extraccio´n de proteı´na es uno de los factores que ma´s efecto ejerce sobre sus propiedades funcionales, debido a su posible desnaturalizacio´n. Un proceso que ofrece menos cambios conformacionales y el nulo uso de efluentes es la molienda y fraccionamiento en seco. Se evaluaron las propiedades fisicoquı´micas y funcionales de una fraccio´n rica en proteı´na de chı´a (FRP) obtenida por procesamiento en seco. Su composicio´n (g/kg) fue de 446,2 de proteı´na y 345,2 de ELN. Tuvo un ma´ximo de solubilidad de 60% a pH alcalino y mı´nimo de 11,7% a pH 4. La actividad emulsificante mostro´independencia del pH y tuvo valores de 50-56%, pero con alta estabilidad (92%) sobre todo a pH de 8 y 10. La FRP no resulto´ser un buen agente espumante, con ma´ximo valor de 29% sin dependencia del pH, pero si exhibio´una buena estabilidad de la misma (80%). Las soluciones diluidas (30 y 40 g/L) presentaron valores altos de viscosidad aparente (10 000 cP) con un comportamiento caracterı´stico de fluido no Newtoniano. La FRP obtenida es un ingrediente potencial para alimentos que requieren estabilidad de emulsio´n o de espuma.

To investigate the genetic diversity and structure of Jatropha curcas L. oilseed plant, in this study, native populations from Chiapas, Mexico, were evaluated, using microsatellite DNA markers. A total of 93 representative samples were selected from seven sites in two regions in the state of Chiapas grouped by geographical proximity, where leaf samples were collected to isolate the genomic DNA. Individual polymerase chain reactions were carried out with ten pairs of specific oligonucleotides for the microsatellites of J. curcas, separating the products of amplification by acrylamide electrophoresis. Twenty-seven fragments were detected (77% polymorphic) with which heterozygous individuals were distinguished. The most informative microsatellite was Jcps20 (nine alleles, polymorphic index content 0.354). The average polymorphism per population was 58%. The Hardy -Weinberg tests revealed a reproductive pattern of non-random mating. The diversity descriptors and the analysis of molecular variance revealed that the populations were structured and moderately differentiated (F ST 0.087) and that this differentiation was not due to isolation by distance, as the Mantel test was not significant (P ¼ 0.137), but rather due to allopatry. Bayesian analysis revealed that the accessions belonged to only four genetic groups and confirmed the differentiation between the regions. Because some loci were in Hardy -Weinberg disequilibrium, it is proposed that differentiation is due to the clonal reproduction of J. curcas practised by farmers in Chiapas, along with the anthropogenic dispersion at regional levels. The results of this study reveal that J. curcas in Chiapas has genetic diversity that is greater than that reported in other parts of the world, which represents a potential germplasm pool for the selection of genotypes.

No abstract