Particle formation during soy protein precipitation

The current success of soy foods is driving soy ingredient manufacturers to develop innovative products for food manufacturers. One such innovation is separating the soy proteins glycinin and beta-conglycinin to take advantage of their individual functional and nutritional properties. Precipitation by acidification is a low-cost method for separating these two proteins. Separation is achieved by preferentially precipitating glycinin at pH ~ 6 while beta-conglycinin remains in solution. Understanding the particle formation during protein precipitation is important as it can influence the efficiency of the precipitation process as well as subsequent downstream processes such as the particle-liquid separation step, usually achieved by centrifugation. Most of the previous soy protein precipitation studies are limited to precipitation at pH 4 as this is the pH range most commonly used in the commercial manufacturing of soy protein isolates. To date, there have been no studies on the particle formation during precipitation at pH > 5.Precipitation of soy protein is generally thought to occur by the rapid formation of primary particles in the size range of 0.1 - 0.3 microns followed by aggregation of these particles via collision to aggregates of size about 1 - 50 microns. The formation of the primary particles occurs on a time scale much shorter than that of the overall precipitation process (Nelson and Glatz, 1985). This study shows that precipitation of soy protein is indeed rapid. At high pH levels, binary liquid-liquid separation occurs forming a protein-rich heavy phase. The protein-rich phase appears as droplets which can be coalesced to form a uniform bulk layer under centrifugation forces. Upon lowering the pH level by the addition of acid, further protein is precipitated as amorphous material which binds the droplets together to form aggregates of amorphous precipitates. Liquid-liquid separation has been observed in many protein solutions but this phenomenon has only scarcely been reported in the literature for soy proteins. It presents an exciting opportunity for an innovative product. Features of the liquid-phase protein such as protein yield and purity will be characterized.

Biodegradable starch-based nanocomposite packaging materials

Polymer processing experiments have been conducted with a twin screw extruder. Different formulations of starch-based nanocomposites are being tested in a pilot scale film blowing tower. The physical properties of different starch-based films have been examined with thermal and mechanical analysis and X-ray diffraction. The results show that the addition of organoclay significantly improves both the processing and tensile properties over the original starch blends. The mechanical and thermal properties of the blends are also sensitive to the scale the clay particles are dispersed.

Optimum coal properties and engineering processes for CO2 geosequestration in Coal

CO2 Geosequestration is seen by many worldwide scientists and engineers as a leading prospective solution to the global warming problem arising from excessive CO2 and other greenhouse gas emissions. CO2 geosequestration in coal seams has two important strategic benefits: the process has an extremely low risk of leakage, due to the adsorbed state of the CO2 and the known reservoir context of essentially-zero leakage into which it is be injected; the second benefit arises from the valuable by-product, clean burning coalbed methane gas. This paper presents the authors’ experience, knowledge and perspective on what coal properties and engineering processes would favour implementing a demonstration or commercial CO2 storage-in-coal project, in Queensland, Australia. As such, it may be considered a template for screening studies to select the optimum coal seam reservoir, and for preliminary studies in designing the injection system and predicting production response to the technology. The paper concludes by examining the current knowledge gaps of CO2 geosequestration in coal, identifying further basic and applied research topics.