Improved Emulsifying and Foaming of Whey Proteins after Enzymic Fat Hydrolysis

In an effort to improve emulsifying and foaming of sweet whey and whey protein concentrate, we studied the hydrolysis of the residual fat in these preparations with a sn 1,3 specific lipase. This enzymatic lipolysis would convert almost all triglycerides into mono- and diglycerides which have strong surface-active properties. Therefore, the emulsifying and foaming capacities of such modified whey products should be increased in comparison with native products, as shown by results presented at both neutral pH and those similar to a salad dressing emulsion. It was also demonstrated that emulsions and foams formed with lipasetreated whey preparations were more shelf-stable.     

Edible composite films of wheat gluten and lipids: water vapour permeability and other physical properties

Edible composite films comprised of wheat gluten as the structural matrix and various concentrations of different lipids as the moisture barrier component were tested for water vapour permeability, dispersion in water, opacity and mechanical properties. the effects of lipids on the functional properties of gluten-based composite films depended on the lipid characteristics and on the interactions between the lipid and the protein structural matrix. Beeswax, a solid and highly hydrophobic lipid, was the most effective lipid for improving moisture barrier properties of films; but these films were opaque, weak and disintegrated easily in water. Combining wheat gluten proteins with a diacetyl tartaric ester of monoglycerides reduced water vapour permeability, increased strength and maintained transparency.     

Inspection and maintenance planning: an application of semi-Markov decision processes

In this paper, we consider a system which deteriorates stochastically from one time unit to another. The state of the system, which is a continuous random variable, can be observed only by inspection. The goal of this paper is to derive a predictive maintenance policy which indicates, at each inspection and according to the observed value, whether a preventive maintenance is necessary and when the next inspection should be done. The objective is to minimize the long-run average cost incurred by inspections, preventive maintenance and unexpected breakdowns. The problem is modelled by a semi-Markov decision process. Analytical properties are derived, and based on these properties, numerical methods are constructed to compute an optimal policy.     

PREDICTION OF SOLIDS CIRCULATION RATE IN THE RISER OF AN INTERNALLY CIRCULATING FLUIDIZED BED (ICFB)

A predictive mathematical model based on pressure drop in the riser of an Internally Circulating Fluidized Bed (ICFB) is developed to predict solids circulation rate (Gs). The values of G_s predicted using the model agree well with the experimental data. The model also predicts well G_s at higher operating temperatures in the riser of an ICFB.     

棉籽抗菌活性肽的分离纯化及鉴定

通过体外模拟消化系统对棉籽分离蛋白(cottonseed protein isolate,CPI)进行酶解,得到具有抗菌活性的酶解产物,并采用超滤(ultrafiltration,UF)、阴离子交换色谱(anion exchange chromatography,AEC)、半制备高效液相色谱(semi-preparation high performance liquid chromatography,semi-P-HPLC)分离技术对棉籽抗菌活性肽进行分离纯化,用电喷雾串联质谱(electrospray ionization-tandem mass spectrometry,ESI-MS/MS)鉴定棉籽抗菌肽的氨基酸序列。在抗菌活性肽分离纯化过程中,用UF对具有抗菌活性的CPI酶解产物进行分离,得到3个组分U-Ⅰ~U-Ⅲ。抗菌活性检测表明U-Ⅲ的抗菌能力最强;用AEC分离U-Ⅲ得到3个组分QF-Ⅰ~QF-Ⅲ,其中QF-Ⅱ抗菌能力最强;进一步采用semi-P-HPLC分离QF-Ⅱ得到4个组分PF-Ⅰ~PF-Ⅳ,其中PF-Ⅲ的抗菌能力最强,经HPLC检测为单一峰,ESI-MS/MS检测分析得到该肽的氨基酸序列为ISGLIYEETR(Ile-Ser-Gly-Leu-Ile-Tyr-Glu-Glu-Thr-Arg)。     

Extruded Microchannel-Structured Heat Exchangers

Abstract

In the search for more compact air/liquid heat exchangers, one possibility is to increase the heat transfer coefficient and surface area by a decrease of the size of the fluid channels. A practical example could be seen in the air/water cross-flow heat exchangers used in cars. For such exchangers, minimization of the total volume leads to a very thin structure, with a lot of small and short air channels. We have designed and patented a cross-flow heat transfer surface with microchannels that has such a structure and can be manufactured industrially at a reasonable cost by extrusion either in aluminum or in polymers. The thermo-hydraulic performance of the structure has been simulated using standard correlations and CFD codes, and prototypic structures are under investigation to validate simulations. Compared to classical heat exchangers, our design is superior in flexibility and compactness for air/liquid applications.