Viscoelastic properties of soy protein isolate - pectin blends: Richer than those of a simple composite material.

Concentrated soy protein isolate (SPI) - pectin blends acquire fibrous textures by shear-induced structuring while heating. The objective of this study was to determine the viscoelastic properties of concentrated SPI-pectin blends under similar conditions as during shear-induced structuring, and after cooling. A closed cavity rheometer was used to measure these properties under these conditions. At 140 °C, SPI and pectin had both a lower G* than the blend of the two and also showed a different behavior in time. Hence, the viscoelastic properties of the blend are richer than those of a simple composite material with stable physical phase properties. In addition, the G'pectin was much lower compared with the G'SPI and G'SPI-pectin upon cooling, confirming that pectin formed a weak dispersed phase. The results can be explained by considering that the viscoelastic properties of the blend are influenced by thermal degradation of the pectin phase. This degradation leads to: i) release of galacturonic acid, ii) lowering of the pH, and iii) water redistribution from the SPI towards the pectin phase. The relative importance of those effects are evaluated.

Overexpression of a GmCnx1 gene enhanced activity of nitrate reductase and aldehyde oxidase, and boosted mosaic virus resistance in soybean.

Molybdenum cofactor (Moco) is required for the activities of Moco-dependant enzymes. Cofactor for nitrate reductase and xanthine dehydrogenase (Cnx1) is known to be involved in the biosynthesis of Moco in plants. In this work, a soybean (Glycine max L.) Cnx1 gene (GmCnx1) was transferred into soybean using Agrobacterium tumefaciens-mediated transformation method. Twenty seven positive transgenic soybean plants were identified by coating leaves with phosphinothricin, bar protein quick dip stick and PCR analysis. Moreover, Southern blot analysis was carried out to confirm the insertion of GmCnx1 gene. Furthermore, expression of GmCnx1 gene in leaf and root of all transgenic lines increased 1.04-2.12 and 1.55-3.89 folds, respectively, as compared to wild type with GmCnx1 gene and in line 10 , 22 showing the highest expression. The activities of Moco-related enzymes viz nitrate reductase (NR) and aldehydeoxidase (AO) of T1 generation plants revealed that the best line among the GmCnx1 transgenic plants accumulated 4.25 µg g(-1) h(-1) and 30 pmol L(-1), respectively (approximately 2.6-fold and 3.9-fold higher than non-transgenic control plants).In addition, overexpression ofGmCnx1boosted the resistance to various strains of soybean mosaic virus (SMV). DAS-ELISA analysis further revealed that infection rate of GmCnx1 transgenic plants were generally lower than those of non-transgenic plants among two different virus strains tested. Taken together, this study showed that overexpression of a GmCnx1 gene enhanced NR and AO activities and SMV resistance, suggesting its important role in soybean genetic improvement.

The cancer preventive peptide lunasin from wheat inhibits core histone acetylation.

Lunasin is a unique 43-amino acid cancer preventive peptide initially reported in soybean and barley and has been shown to be chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. We report here the core histone H3- and H-acetylation inhibitory properties of lunasin from wheat, a new source of the peptide and from the livers of rats fed with lunasin-enriched wheat (LEW) to measure bioavailability. A non-radioactive histone acetyl transferase assay was used to measure inhibition of core histone acetylation. The presence of lunasin in wheat was established by Western blot and identified by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). Lunasin isolated from wheat seeds at different stages of development inhibited core histone H3 and H4 acetylation in a dose-dependent manner. Lunasin extracted from liver of rats fed with lunasin-enriched wheat (LEW) also inhibited histone acetylation confirming that the peptide is intact and bioactive. The amounts of lunasin in the developing seeds and in the rat liver correlated extremely well with the extent of inhibition of core histone acetylation.

Nuclear receptors: potential biomarkers for assessing physiological functions of soy proteins and phytoestrogens.

Soy consumption is associated with decreased incidence of chronic diseases, including cardiovascular diseases, atherosclerosis, diabetes, osteoporosis, and certain types of cancers. However, consumption of high amounts of soy isoflavones may adversely influence endocrine functions, such as thyroid function and reproductive performance, because of their structural similarity to endogenous estrogens. Nuclear receptors are a group of transcription factors that play critical roles in the regulation of gene expression and physiological functions through direct interaction with target genes. Modulation of the abundance of these receptors, such as changing their gene expression, alters the sensitivity of the target cells or tissues to the stimulation of ligands, and eventually affects the relevant physiological functions, such as growth, development, osteogenesis, immune response, lipogenesis, reproductive process, and anticarcinogenesis. A number of studies have shown that the bioactive components in soy can modify the expression of these receptors in various tissues and cancer cells, which is believed to be a key intracellular mechanism by which soy components affect physiological functions. This review summarizes the current understanding of the modulation of nuclear receptors by soy proteins and isoflavones, and focuses especially on the receptors for estrogens, progesterone, androgen, vitamin D, retinoic acid, and thyroid hormones as well as the potential impact on physiological functions.