聚赖氨酸对鲜榨玉米汁保鲜效果的研究

通过单因素试验和正交试验,确定了聚赖氨酸在玉米汁饮料中的最大使用量、最佳使用量,并确定了在玉米汁饮料中与聚赖氨酸组合的最佳制剂以及复配防腐剂的最佳配方。试验结果为：玉米汁饮料中使用聚赖氨酸的最大范围是0．02％;玉米汁饮料中单独使用聚赖氨酸的最适量为0．003％;玉米汁饮料添加最适聚赖氨酸浓度为0．003％,甘氨酸浓度为0．5％;防腐剂复配最佳组合为0．003％聚赖氨酸、0．5％甘氨酸、0．05％山梨酸钾、0．03％双乙酸钠、0％Nisin、0．003％EDTA。在玉米汁饮料中添加上述制剂,保鲜期可达到6d。     

Inhibitory effects of flavonoid glycosides isolated from the peel of Japanese persimmon (Diospyros kaki Fuyu) on antigen-stimulated degranulation in rat basophilic leukaemia RBL-2H3 cells

We found that two distinct flavonoid glycosides isolated from the peel of Japanese persimmon (Diospyros kaki Fuyu), isoquercitrin (Isq) and hyperin (Hyp), are capable of inhibiting antigen-stimulated degranulation in rat basophilic leukaemia RBL-2H3 cells. In order to elucidate the underlying mechanisms, we examined effects of Isq and Hyp on cellular responses induced by antigen stimulation. Treatment with both Isq and Hyp markedly inhibited antigen-stimulated elevation of intracellular free Ca²⁺ concentration and reactive oxygen species (ROS). Isq and Hyp did not affect NADPH oxidase (NOX) activity, but they possessed DPPH radical-scavenging activity similar to that of epigallocatechin gallate, a potent anti-oxidant, Finally, Isq and Hyp showed little or no effects on Ag-stimulated Syk activation or phosphorylation of signalling molecules. These results indicate that inhibition of antigen-stimulated degranulation by Isq and Hyp is mainly due to suppression of intracellular Ca²⁺ elevation, which is caused by direct scavenging of ROS that are generated by NOX. Our findings suggest that Isq and Hyp, isolated from the peel of persimmon, would be beneficial for alleviating symptoms of type I allergy.     

枸杞菊花保健玉米面包的研制

以小麦粉和玉米粉为主要原料,加入枸杞和菊花制得的浸提液以及蜂蜜等辅料,研制成枸杞菊花保健玉米面包。并通过实验确定其最佳配方和最优工艺条件。     

成熟玉米果穗脱皮装置的研究

为了提高玉米果穗苞叶脱皮环节的苞叶脱净率,通过脱皮辊作业时果穗的受力分析,解析了果穗与苞叶被分离以及果穗未被拧取的作业条件,建模并进行数理分析。结果表明：分离辊拽拉玉米苞叶作用力大于拽拉玉米苞叶所需作用力或拧取角减小到最佳值n满足上述两个基本条件时,本研究装置苞叶脱净率可达97%。     

Biological activities of Solanum paludosum Moric. extracts obtained by maceration and supercritical fluid extraction

Solanum paludosum extracts obtained by maceration (SP-EtOH_CRUDE and SP-EtOH_MARC) and supercritical fluid extraction (SP-SFECO₂) were evaluated. Three extracts with distinct chromatographic profiles were obtained: SP-EtOH_CRUDE, with a complex phenolic composition; SP-SFECO₂, containing methoxylated flavonoids; and SP-EtOH_MARC, which bears mainly polar polyphenols. All extracts were strong antioxidants, as measured using the diphenylpicrylhydrazyl (DPPHcom/scidirimg/entities/rad" style="vertical-align:middle;">) method, xanthine/xanthine oxidase/luminol and iron-induced lipid peroxidation systems. Extracts were also evaluated as modifiers of antibiotic activity in strains of Staphylococcus aureus expressing fluoroquinolone, macrolide and tetracycline efflux proteins. Despite their lack of antibacterial activity, all extracts were able to potentiate antibiotics activities by as much as eight fold. Both the maceration and supercritical fluid extraction processes were adequate to obtain extracts with different biological activities according to their patterns of phenolic compounds. The data suggest that S. paludosum could be a valuable source of antioxidants and putative efflux pumps inhibitors.     

Novel synthetic strategy toward shape memory polyurethanes with a well-defined switching temperature

Shape memory polyurethanes (SMPUs) have been synthesised via a novel synthetic methodology, resulting in an improvement of the phase separation in the multi-block structure of the polyurethane and in its shape memory properties. ABA block copolymers based on semi-crystalline poly(com/scidirimg/entities/25b.gif" alt="var epsilon" title="var epsilon" border="0">-caprolactone) and amorphous poly(propylene oxide) (PPO) were used as precursor for the SMPUs. For their synthesis, poly(com/scidirimg/entities/25b.gif" alt="var epsilon" title="var epsilon" border="0">-caprolactone) diols have been converted into isocyanate end-capped prepolymers by using a mixture of 3(4) isocyanato-1-methyl-cyclohexylisocyanate isomers, after which a coupling with low-T_g poly(propylene oxide) oligomers is done. The shape memory polymers are obtained by reaction of the ABA block copolymers with hexamethylenediisocyanate and 1,4-butanediol as chain extender. Using this new strategy, a flexible segment (PPO) was introduced between the hard and the switching segments of the SMPU. For comparison, SMPUs without flexible segment have also been prepared with the conventional synthetic route. DSC, isostrain experiments and cyclic shape memory tests revealed narrower switching temperatures for the SMPUs including a flexible segment.     

Comparative analysis of sex-pheromone-response antagonists in three races of European corn borer

Behavioral responses of males from three New York races of European corn borer,Ostrinia nubilalis (Hübner), to various suspected sexpheromone-response antagonists were investigated with a flight tunnel protocol. Males from a bivoltine (Z) race and from a univoltine (Z) race utilizing a natural pheromone blend of 982 (Z)-(E)-11-tetradecenyl acetates and males from a bivoltine (E) race utilizing a 199 (Z)-(E)-11-tetradecenyl acetate ratio were flown to their natural blends and to blends containing 1 % of one of the following additional compounds: Z9–12OAc,E9–12OAc,Z9–14OAc, andE9–14OAc. In each race, the added components lowered significantly the number of individuals completing the behavioral sequence. The only exception was bivoltineE males flown to a blend withE9–12OAc added. The number completing the sequence in this case was statistically not significantly lower than the number that completed the sequence to the standard blend. In all three races, theZ9–14OAc produced the most dramatic reduction in completed flights, and in the univoltineZ race, this added component was significantly more effective in reducing completed flights than any other added component. The response to the Z9–14OAc is understandable given recently published findings of an electrophysiological study of single sensilla in the European corn borer.     

玉米秸秆生物产氢菌的分离培养及鉴定研究

以牛粪为菌种来源,利用玉米秸秆进行厌氧发酵产氢实验,在产氢效果达160 mL/h,秸秆产氢能力225 mL/g的最佳状态下,从实验中提取发酵菌液进行细菌的分离培养,并对产氢效果最好的R-3菌种进行生理生化试验研究和初步鉴定,确定产氢细菌为Clostridium sp.Fanp2.