Advanced Materials Research Vols. 396-398

Abstract: Mig1p, a zinc finger class of DNA-binding protein, plays a critical role in glucose repression for maltose utilization in Baker’s yeast. Maltose is the hydrolyzate of starch, which is the main component of dough. In this study, the recombinant yeast strains with MIG1 gene deletion were constructed, and the maltose metabolism of the parental and mutant strains in batch cultivations were investigated. Our results show that the degree of glucose repression of mutants △MIG1α and △MIG1a are reduced by 49.88% and 41.59% respectively compared to their parental strains, suggesting that MIG1 deletion can partially relieve glucose repression of maltose metabolism.

Abstract: The effect of reconstituted milk inoculation with Streptococcus thermophilus TM11 and Streptococcus thermophilus SP 1.1 on soft cheese volatiles was investigated. The impact flavors of 2,3-butanedione, 2,3-pentanedione, ethyl acetate, methyl butyrate, ethyl butyrate, butyl acetate and butyric acid were only detected in the fermented cheeses. Levels of diketones were higher in the cheeses fermented by mixed cultures than single culture, while levels of esters except ethyl acetate and butyl acetate showed an opposite tendency. There was significant difference in the levels of 2-hexenal and 2-nonenal among the cheeses. Other compounds originated from lipid oxidation, Strecker degradation, biosynthesis and forages were not significantly influenced by milk inoculation with Streptococcus thermophilus.

Abstract: Two stains (SP1.1 and TM11) of Streptococcus thermophilus were evaluated for the production of soft cheese using reconstituted milk powder. Analysis of cheese composition showed that the stains possessed good acidifying activity. When S. thermophilus TM11, an exopolysaccharide-producing stain, was added in combination with SP1.1, the texture variables of hardness, springiness and cohesiveness decreased and the adhesiveness increased. Furthermore, the microstructure of the cheese cultured with S. thermophilus TM11 was less hard and showed more opened cavities than other cheeses. It was conclusion that S. thermophilus TM11 could be used to improve the texture properties of this soft cheese.

Abstract: In the commonly used automobile oil filtering materials,having a single layer structure,also having two layer structure and three layer structure,this paper firstly selected four diverse structural filter materials of automobile oil filter cartridge and then discussed their internal structure and property.Putting to use of SEM to analyze their inner construction and research their physical performance and filtration property.The results indicated that the two layer material possesses smaller pore diameter,higher filtration accuracy and better filtration effiency,however,the three layer material is not in the nature of excellent filtration accuracy,therefore,in the process of exploitation of novel filtration material,the target is not to increase it’s layer but realizing how to improve the filter efficiency.The monolayer material is mainly the nonwoven and has ordinary filtration effiency.As a result,in the attempt of developing new filtration materials,the aim needs to focus on the two layer new materials,meanwhile,the other objective is to improve the filtration accuracy to nanometer scale.

Abstract: The preparation conditions in the water system of phenylalanine chelated calcium complex have been evaluated though single-factor tests and optimized by uniform design. Then the optimal parameters were obtained as follows: reaction temperature is 40 °C, reaction time is 182 min, the molar ratio of phenylalanine to calcium is 4.3 and pH = 9.0. Under the best conditions, the experimental result gives chelating rate = 87.40% that is 17.12% lower than the prediction = 104.52%.The infrared spectrum characterization has confirmed the formation of phenylalanine-Ca²⁺ chelates and the existence of chelate ring.

Abstract: Conformational changes of wild-type (WT) hIAPP and the S20P mutant in explicit water are investigated using molecular dynamics. In the whole simulation, WT shows compacter structure and has more hydrogen-bond networks than S20P. The residues 14-18 in WT is always maintained as a helical structure which is stabilized by the hydrogen bond between Ser20 and NH group of His18, and the other regions in WT partially loosen from α-helix structures into the coil structures. The S20P mutant in a shortage of hydrogen-bond interaction unfolds faster than WT. This work provides insight into the specific conformation of IAPP which is associated with the generation of amyloid fibrils.

Abstract: Hydrothermal depolymerization of DGEBA/EDA epoxy resin was carried out in a stainless autoclave at temperatures of 270°C to 350°C in H₂O medium. The effect of the factors catalyst, temperature and time on the depolymerization was researched. The products of depolymerization were analyzed qualitatively and quantitatively by means of GC/MS and GC. The results indicated that the main depolymerized products were phenol, p-isopropylphenol and bisphenol-A (BPA). The epoxy resin composite based on glass fiber and the solid residue after reaction using catalytic hydrothermal depolymerization technology were analyzed by SEM. Also, the depolymerization kinetics of epoxy resin with 3% catalyst and no catalyst were researched and the activation energy was calculated.

Abstract: Abstract. Water-extracting enzyme from plants is used in practice because of simple and low cost. The sweet potato was taken as material to extract -amylase, the optimized parameters were studied. The results showed that the optimized parameters were as follows: extraction temperature 60°C, the level of reducing agent NaHSO3 1.5 g/L, the ratio of water to sweet potato 2:1, pH 5.0-5.5, extraction time 0 h. Under the optimum technological conditions, the β-amylase activity was 113096.9±2445.7 U/g. The study of β-amylase from sweet potato is of great theoretical and practical significance to the β-amylase industrialization production.

Abstract: The experiments of Rumex japonicus Houtt root effective parts for preliminary separation provide the further research of the effective components conditions.

Abstract: Simultaneous distillation and extraction (SDE), Gas chromatography-mass spectrometry (GC-MS) are used to analyze the volatile flavor compounds of bean sprouts, which are fermented with composite strains of different compatibility .The results showed that bean sprouts fermented by compound bacteria AN1: AE produced maximum flavor compounds. The number of the flavor compounds is 22, of which 5 were alcohols, 11 were esters and 6 others. Combined with organoleptic investigation, compound bacteria AN1: AE were preliminarily picked up as the best fermentation strain of bean sprouts