A two‐step inoculation of Candida etchellsii to enhance soy sauce flavour and quality

Effects of novel two‐step inoculation to enhance soy sauce special flavour in Candida etchellsii were investigated at the cell growth phase. The first‐stage consists of a 5% culture inoculum of log phase cells at 30‐day. Subsequently, a 20% culture inoculum of stationary phase cells was added at 60‐day. The resulting amino nitrogen and soluble salt‐free solid yield reached 9.15 ± 0.12 and 269.60 ± 3.15 mg L^?1 in 30 °C incubator experiments, increased by 23.1% and 17.6%, respectively, as compared to the control without culture inoculation. Maximal free amino acid yield of 58.21 ± 1.77 g L^?1 was achieved, and 39 types of volatile flavour compounds content was 17.81 ± 0.45 g L^?1, which were 1.76% and 178.7% higher than the control. A novel two‐step inoculation using the C. etchellsii yeast was developed and optimised. It was proven to be a feasible reproducible process for industrial application for the improvement of the flavour and quality of soy sauce production.     

The influence of oxidizing agents on water extracts of rye flour

The main constituents of rye flour extracts are proteins and pentosans. After cross-linking under the action of oxidizing agents those components are able to bind much more water than in their native (prior to modifications) state. As a consequence rheological properties of extract are changed.It was observed that kinematic viscosity of water extract of rye flour decreases rapidly with time. The reason for this behavior could be high enzymatic activity of flour extract.It was also found that the addition of hydrogen peroxide in the absence of additional peroxidase (which is naturally present in 1:9 or 1:1 water extracts of flour) causes the greatest increase in viscosity, due to the cross-linking of soluble polymers. Moreover after the addition of H₂O₂ to water extracts strong gels were obtained, which were characterized by tan δ = 0.5 (tan δ < 1). Moreover G′ was independent of frequency, which also suggests cross-linking of the pentosans.The addition of ascorbic acid, which is known to act preferably on gluten proteins, to 1:9 or 1:1 flour extracts had only a little effect on viscosity. In this case the values of tan δ = 0.9 were close to 1, which is typical for a weak gel.The application of inactivated rye flour extract, containing mainly proteins and pentosans, proved stronger effect of H₂O₂ in comparison to ascorbic acid on polymer cross-linking, but only after the addition of peroxidase. The gel obtained with H₂O₂ and peroxidase was also characterized by low tan δ = 0.4.The results indicate, that pentosans are the main subject of cross-linking reactions in rye flour water extracts.     

Rheological properties of wheat flour and quality characteristics of pan bread as modified by partial additions of wheat bran or whole grain wheat flour

The use of bran and whole grain flour changes dough rheology and causes difficulties in manufacturing bakery products. The aim of this study was to analyse the influence of substituting refined wheat flour (WF) by wheat bran (WB; 5%, 10%, 20%, 30% and 40%) or whole grain wheat flour (WGWF; 10%, 20%, 30%, 40% and 50%) on dough rheological properties and pan bread quality characteristics. The addition of WB and WGWF increased water absorption and resistance to extension and decreased stability, extensibility and peak viscosity. Effects with WB were more pronounced. The presence of WB or WGWF increased crumb moisture content, firmness and hardness and decreased specific volume of pan bread. It is important to set new farinographic and extensographic standards when using WB and WGWF, allowing for a correct correlation between rheology and quality characteristics of bakery products, as the same standards used for WF are not valid.     

Effects of larval crowding and nutrient limitation on male phenotype,reproductive investment and strategy in Ephestia kuehniella Zeller (Insecta: Lepidoptera)

Food shortage experienced by juvenile insects affects adult morphology and life-history traits. Developmental plasticity and trade-off between ecological and sexual traits helps maximise individual fitness. Ephestia kuehniella were reared at different larval densities to investigate phenotypic shifts in adult males. Variation in ecological traits (sizes of forewing, head and thorax and adult longevity) and sexual traits (valva and aedeagus, sperm number, mating frequency) were compared. Males that emerged from highest density population (800) had lower body mass and small forewings, head and thorax, suggesting that they could not completely compensate for food shortage. The allometric relationship between body mass and forewing length also changed, and these males had relatively longer wings. This arrangement may enhance dispersal and assist in mate-searching at higher densities. Males from all larval densities achieved similar mating frequency but those from higher density produced fewer eupyrene sperm and had shorter adult lifespan. By mating more frequently and maintaining apyrene sperm production, males increase their reproductive success at sperm competition observed at higher densities. Food stress associated with high density populations did not affect valva and aedeagus size indicating that these traits may be insensitive to external environmental changes because they incur fitness costs to males.     

HDPE/木粉改性复合材料的制备及其长效吸水性能研究

加入HDPE-g-MAH、CG-8831和KH-550制备HDPE/木粉改性复合材料。研究其长效吸水性,发现吸水率随时间延长先快速增加,浸水35 d后缓慢增至平衡,HDPE-g-MAH改性效果最好,其饱和吸水率仅为1.503%。利用Fick第二扩散定律拟合吸水动力学曲线,得扩散系数D的顺序:HDPE-g-MAH增容HDPE/木粉复合材料HDPE/木粉复合材料KH-550改性HDPE/木粉复合材料CG-8831改性HDPE/木粉复合材料。并证明该吸水过程符合Fick第二扩散定律,相关系数R2值达0.99以上。HDPE/木粉改性复合材料尺寸变化系数CDCWCT。     

采用红外光谱鉴别天然胶乳掺假的分析与处理

在天然胶乳中按不同比例掺入木薯粉或面粉,制备掺假天然胶乳,采用傅里叶转换红外光谱进行表征和分析。 结果表明：在天然胶乳中掺入木薯粉或面粉,红外光谱在3 500～4 000 cm-1波段出现指纹区,掺入量越高,指纹区的波动幅度越大;在木薯粉或面粉的特征谱带,随着掺入量的增大,吸收强度增强。     

利用富硒双孢菇粉提升酱油有机硒含量和改善酱油风味

该研究利用临期和损伤富硒双孢菇制备富硒双孢菇粉,以其替代15%质量分数的面粉,按照高盐稀态工艺生产富硒酱油（样品酱油）。结果显示,样品酱油总硒和有机硒含量分别达到134.65和122.53μg/kg,比对照酱油提高5.70倍和5.85倍,有机硒转化率为91.00%,符合富硒酱油标准。理化分析结果表明样品酱油总氮、氨基酸态氮和无盐固形物含量为1.72、1.03和22.56 g/100 mL,比对照酱油提高9.55%、19.77%和5.13%。此外,样品酱油蘑菇香、麦芽香、醇香和果香香气强度比对照酱油提高了5 837.17%、15.62%、20.15%和15.88%。添加富硒双孢菇粉显著提高了大曲和酱醪中蛋白酶酶活,这是富硒双孢菇粉提高酱油滋味物质含量的原因。富硒双孢菇粉中的1-辛烯-3-酮、1-辛烯-3-醇、3-辛醇和3-辛酮赋予了样品酱油蘑菇香。此外,富硒双孢菇粉促进了酱醪中产香微生物的繁殖,进而提高了样品酱油中麦芽香、醇香和果香香气强度。该研究利用临期和损伤富硒双孢菇开发了一种风味良好的富硒酱油,可为双孢菇和酱油生产企业提高产品附加值提供技术参考。