Membranes for separation of biomacromolecules and bioparticles via flow field‐flow fractionation

Flow field‐flow fractionation (FlFFF) is a liquid‐phase separation technique that can separate macromolecules and particles on the basis of differences in their diffusion coefficient, and therefore their size. The membrane in the FlFFF channel is one of the most important elements involved in accomplishing the separation. This mini‐review focuses on requirements and important points related to membranes used in FlFFF channels. Unless it is selected properly, the membrane can be a weak point of the technique due to risks such as sample loss because of the interactions between the sample and the membrane. © 2014 Society of Chemical Industry     

Progress in micellar casein concentrate: Production and applications

Micellar casein concentrate (MCC) is a novel ingredient with high casein content. Over the past decade, MCC has emerged as one of the most promising dairy ingredients having applications in beverages, yogurt, cheese, and process cheese products. Industrially, MCC is manufactured by microfiltration (MF) of skim milk and is commercially available as a liquid, concentrated, or dried containing ≥9, ≥22, and ≥80% total protein, respectively. As an ingredient, MCC not only imparts a bland flavor but also offers unique functionalities such as foaming, emulsifying, wetting, dispersibility, heat stability, and water-binding ability. The high protein content of MCC represents a valuable source of fortification in a number of food formulations. For the last 20 years, MCC is utilized in many applications due to the unique physiochemical and functional characteristics. It also has promising applications to eliminate the cost of drying by producing concentrated MCC. This work aims at providing a succinct overview of the historical progress of the MCC, a review on the manufacturing methods, a discussion of MCC properties, varieties, and applications.     

尿素包埋法富集椰子油中月桂酸工艺条件优化

研究了尿素包埋法富集椰子油中月桂酸工艺。以椰子油为原料通过皂化酸解制备椰子油混合脂肪酸,然后对混合脂肪酸进行尿素包埋富集月桂酸。通过单因素实验和正交实验法优化,得到影响包埋效果的6个因素的主次顺序为水浴温度包埋时间尿素与混合脂肪酸质量比水浴时间尿素与甲醇质量比包埋温度。尿素包埋法富集椰子油中月桂酸的优化工艺条件为:尿素与甲醇质量比1∶2,包埋温度-20℃,包埋时间10 h,尿素与混合脂肪酸质量比1∶1. 5,水浴温度50℃,水浴时间5 h。在优化工艺条件下,富集后月桂酸含量为60. 05%,较富集前的50. 70%提高了9. 35个百分点。     

Concentration of Omega‐3 polyunsaturated fatty acids by polymeric membrane

Omega‐3 is a polyunsaturated fatty acid (PUFA), which is an essential nutrient for health. Through this, the ω3‐PUFA concentration has increasingly gained interest. In this study, the concentration of ω3‐PUFA of Lantern fish oil was investigated through utilisation of membrane separation. Between tested membranes, it was observed that ETNA01PP separates ω3‐PUFA more selectively. Additionally, effects of main parameters affecting the ω3‐PUFA concentration, including temperature (20–40 °C), pressure (3–5 bar) and stirring rate (0–200 rpm), were evaluated through Box–Behnken design of experiment. According to anova , all these parameters showed significant impact on ω3‐PUFA concentration. To determine the optimal process parameters, the Derringer's desirability prediction tool was employed in which the highest ω3‐PUFA concentration of 35.1058 wt. % was estimated. The obtained optimal condition was found to be the temperature of 36.19 °C, pressure of 4.82 bar and stirring rate of 43.01 rpm with a desirability value of 0.99.     

On the measurement of critical micelle concentrations of pure and technical-grade nonionic surfactants

The critical micelle concentrations (CMC) of nine commercial nonionic surfactants (Tween 20, 22, 40, 60, and 80; Triton X-100; Brij 35, 58, and 78) and two pure nonionics [C₁₂(EO)₅ and C₁₂(EO)₈] were determined by surface tension and dye micellization methods. Commercially available nonionic surfactants (technical grade) usually contain impurities and have a broad molecular weight distribution owing to the degree of ethoxylation. It was shown that the surface tension method (Wilhelmy plate) is very sensitive to the presence of impurities. Much lower CMC values were obtained with the surface tension method than with the dye micellization method (up to 6.5 times for Tween 22). In the presence of highly surfaceactive impurities, the air/liquid interface is already saturated at concentrations well below the true CMC, leading to a wrong interpretation of the break in the curve of surface tension (γ) vs. concentration of nonionic surfactant (log C). The actual onset of micellization happens at higher concentrations, as measured by the dye micellization method. Furthermore, it was shown that when a commercial surfactant sample (Tween 20) is subjected to foam fractionation, thereby removing species with higher surface activity, the sample yields almost the same CMC values as measured by surface tension and dye micellization methods. It was found that for monodisperse pure nonionic surfactants, both CMC determination methods yield the same results. Therefore, this study indicates that precaution should be taken when determining the CMC of commercial nonionic surfactants by the surface tension method, as it indicates the surface concentration of all surface-active species at the surface only, whereas the dye method indicates the presence of micelles in the bulk solution.