Physicochemical, structural and functional properties of protein isolates and major protein fractions from common vetch (Vicia sativa L.).

Common vetch (CV), a leguminous crop cultivated for green manure and fodder rich in protein and starch, is widespread over much area of the northern hemisphere. Its seeds can be used as a protein source to human consumption. CV protein isolates (CVPI) and major protein fractions (CV albumin protein, CVAP; CV globulin protein, CVGP; CV glutelin protein, CVGTP) from 4 samples were investigated the properties to facilitate full use of protein resources. Protein comprises 27.70 %-32.14 % of the dry CV seed weight, which is mainly composed by CVAP (26.79 %-56.12 %) and CVGP (22.78 %-52.42 %). CVPI, CVAP and CVGP mainly presented 7S and 11S components. CVGTP mainly contained the 11S component. They showed difference in thermal properties and surface hydrophobicity. Circular dichroism data showed that α-helix was their major secondary structure. CVPI and major protein fractions exhibited a U-shape protein solubility. CVPI and CVAP had advantages in emulsifying and foaming properties. This study provided novel insights on unexploited sources of CV proteins with interesting characteristics in terms of potential uses as protein-based foods.

Effects of mixing temperature on the extrusion rheological behaviors of rubber-based compounds.

In this study, rim strip (R) and sidewall (S) compounds were prepared at varying initial mixing temperatures. The effects of the mixing temperature on the extrusion rheological behaviors of the compounds were investigated, and the relationships between the compound structure and the extrusion rheological behaviors were studied. The results showed that the tensile stress relaxation rates of both R and S were more sensitive to the mixing temperature than the shear stress relaxation rate, and the former was affected by both the dispersion of carbon black (CB) and the actual molecular weight of the rubbers. Strain sweep results showed that R, which had a higher CB content, had a more obvious Payne effect than S. When the initial mixing temperature increased from 80 °C to 90 °C, both storage modulus (G') at a low shear strain and the ΔG' of R obviously decreased, indicating CB dispersion improvement. The S extrudates showed higher die swell ratios (B) than the R extrudates, and the former was more sensitive to mixing temperature. The main factors influencing the B of the R and S were the CB dispersity and the molecular weight, respectively. In addition, at high extrusion rates, a sharkskin phenomenon could be observed for the R extrudate surfaces, whereas the S extrudates were more likely to be integrally distorted.

Prominent Crystallization Promotion Effect of Montmorillonite on PTT/PC Blends with PTT as the Continuous Phase.

To regulate the crystallization of poly(trimethylene terephthalate) (PTT) retarded by melt blending with polycarbonate (PC), the crystallization of the PTT/PC blend was investigated employing nano-montmorillonite (MMT) as a crystallization promoter with PTT as the continuous phase. The results showed that MMT exhibits a significant promoting effect on PTT crystallization; the presence of 1 wt. % MMT shifts the initial and peak crystallization temperatures of the 70/30 PTT/PC blend to ~17 °C and ~32 °C, respectively. Additionally, the full width at half maximum (FWHM) narrows by ~45%, and the ΔHc increases by 3.7 J.g-1. The accelerating effect of MMT is determined by its distribution and dispersion which depends on the shear intensity, mixing mode, and loading. MMT is easier to exfoliate via the two-step method than by the one-step method. The distribution in the PTT phase is enriched along the phase interface forming an MMT layer. This endows sections of the PTT with abundant nuclei and thus crystallization is promoted markedly compared with the one-step method. Moreover, the finer MMT migrates more readily to the interface to cause a much smoother phase interface. However, a secondary crystallization peak appears when the shear force is not sufficient enough to make MMT finely dispersed, in case of the two-step method and the MMT content is increased to 3 wt. %. The mixing temperature shows little effect on the acceleration of MMT on the crystallization of PTT/PC compared with the shear force. Only when MMT did not exfoliate or uncomplete did the presence of epoxy resin help to promote crystallization because of the improved MMT dispersion.