Influence of different sugar sources,nitrogen sources and inocula on the quality characteristics of apple tea wine

An infusion of tea leaves was prepared using 4 g tea/100 mL of the apple juice, ameliorated with different sugar sources, supplemented with different nitrogen sources and inoculated with 5% incola (Saccharomyces cerevisiae var. ellipsoideus , consortia 1 and consortia 2). The highest rate of fermentation and ethanol were found in the apple tea wine having sucrose as a sugar source, while apple juice concentrate as a sugar source gave the highest total phenols, caffeine content and overall acceptability. Higher alcohols, volatile acidity and antioxidant activity were the highest in honey as a sugar source. Apple tea wine having DAHP as a nitrogen source documented the highest ethanol, caffeine content and overall acceptability, lowest higher alcohols, whereas peptone as a nitrogen source had the highest total phenols. Among the different types of inocula, for most of the parameters there were non‐significant differences. However, must inoculated with S. cerevisiae var. ellipsoideus for the preparation of apple tea wine resulted in the highest fermentation efficiency, ethanol and overall acceptability but the lowest volatile acidity. Apple tea wine prepared by ameliorating the apple tea must with apple juice concentrate, DAHP and inoculated with S. cerevisiae var. ellipsoideus was rated as the best. Copyright © 2017 The Institute of Brewing & Distilling     

江西修水双井绿茶加工技术

本文重点论述了江西修水双井绿茶制作过程中各工序控制重点。采摘特级采雨前茶,以一芽一叶初展为主;一、二级采节前茶,一级以一芽一叶为主,二级以一芽一叶与一芽二叶约各半。摊青一般约需2-5h,杀青锅温120-150℃,先高后低,每锅投叶量300-400g。揉捻加压要轻,揉时要短。初焙温度90℃左右,以焙至叶子不粘手为适度。整形搓条锅温60-80℃,团条锅温60℃左右,约八成干时转入提毫。提毫锅温40-50℃,提至白毫显露转入复焙。复焙温度60-70℃,先高后低,焙至含水率5%-6%时下焙。     

Changes of porcine pancreas α‐amylase in activity and secondary conformations under inhibition of tea polyphenols

To investigate two‐sided functions of tea polyphenols (TP) in antinutrition and energy balance modulation, TP were extracted from Chinese green tea and used to complex porcine pancreas α‐amylase (PPA). Changes of PPA in activity and secondary conformations were analysed. Porcine pancreas α‐amylase was found sensitive to TP treatment. Tea polyphenols exhibited IC₅₀ at 0.41 mg mL^?1 against PPA and maximum inhibitory rate (98.17%) at 3.0 mg mL^?1. Tea polyphenols inhibition was concluded as noncompetitive pattern based on its unchanged Km value (0.98 mg mL^?1) for soluble starch substrate. Tea polyphenols inhibition arose from pH 1.5 to 10.14, covering gastric and intestinal environments inside body. Circular dichroism spectra analysis revealed regular changes of PPA in secondary conformations (increased proportions of α‐helix and β‐sheet) prior to its inactivation at low TP concentrations. Tea polyphenols‐inhibited PPA had distinct double‐negative peaks at 204 nm and 208 nm. Porcine pancreas α‐amylase was inactivated by TP in ways of complexation and modification of secondary conformations.     

Effects of polysaccharides and polyphenolics fractions of Zijuan tea (Camellia sinensis var. kitamura) on α‐glucosidase activity and blood glucose level and glucose tolerance of hyperglycaemic mice

The effects of polysaccharides, theaflavins, thearubigins and theabrownin fractions of Zijuan tea on α‐glucosidase and blood glucose level and intolerance of hyperglycaemic mice were evaluated. The polysaccharides or theaflavins fraction exhibited greater inhibition rate of α‐glucosidase than acarbose positive control, thearubigins fraction or theabrownin fraction. The four fractions were delivered to the treatment mice through oval gavage each day for 15 days. The mice in polysaccharides and theaflavins high‐ and low‐dose and theabrownin high‐dose treatments significantly lowered their blood glucose levels while all the treatment mice gained body weight. The mice in polysaccharides, theaflavins and theabrownin high‐ and low‐dose treatments had greater glucose tolerance as well. Thus, the theaflavins and polysaccharides fractions of Zijuan tea effectively moderated the complications of hyperglycaemic mice. The lower effectiveness of thearubigins and theabrownin fractions may be caused by the highly polymerised polyphenolics which decreased their accessibility to α‐glucosidase and digestibility in mice.     

Describing a strategy to estimate the CO2-heavy oil minimum miscibility pressure based on the experimental methods

To measure MMP, slim tube method is time consuming, especially for heavy oils. In this study, a strategy is considered to measure the MMP in one of the Iranian heavy oil reservoirs. The strategy steps were done through; partial data of slim tube, coupling numerical model (CNM), full slim tube, and VIT test. The results showed that CNM technique with two experimental data obtains the MMP value faster than running a full slim tube with low error result. However, VIT determined MMP faster and its results illustrated that miscibility pressure for heavy oil occurs at zero IFT, unlike light oils.     

Effects of green tea powder on the quality attributes of hard red winter wheat flour and Chinese steamed bread

The effects of green tea powder (GTP) on the properties of hard red winter (HRW) flour and Chinese steamed bread were investigated. GTP was blended with HRW flour at levels of 0.00, 1.00, 2.00, 3.00 and 4.00 g GTP/100 g wheat flour. With the addition of GTP, the maximum torque of flour became stronger. The resilience and degree of green colour of steamed bread increased, while hardness and chewiness decreased, with the addition of GTP. The addition of 1.00% GTP did not significantly affect the specific volume, but remarkably influenced the hardness and resilience of steamed bread. In steamed bread formulated with GTP, the antioxidant activity was 0.84 mm TE per g at 1.00% of GTP and increased with GTP levels. The steamed bread had a pleasant flavour, and the degree of overall liking of steamed bread increased with GTP levels to the maximum used in this work.     

Quality identification and evaluation of Pu‐erh teas of different grade levels and various ages through sensory evaluation and instrumental analysis

To develop an objective, effective, flexible and cost‐saving method to assess Pu‐erh tea quality, Pu‐erh tea samples of different grade levels and various ages were analysed using sensory evaluation and various instrumental techniques, including chemical analysis and electronic tongue (ET). Results showed that taste profile analysis as a sensory evaluation method can meticulously describe and distinguish different Pu‐erh tea samples. Chemical analysis combined with hierarchical cluster analysis can cluster Pu‐erh ripened and raw tea both in compressed and scattered forms. However, no obvious variation tendency was observed in the chemical composition parameters of Pu‐erh tea of different grade levels or various ages. ET combined with principal components analysis (PCA) is effective in classifying Pu‐erh tea samples of different grade levels and various ages. ET followed by linear discriminant analysis (LDA) performs well in identifying Pu‐erh tea samples of various ages by establishing a discriminant model.     

Production of yellow wine from Camellia Oleifera meal pretreated by mixed cultured solid‐state fermentation

Camellia oleifera meal was evaluated to be a potential feedstock for the production of yellow wine (YW), and process conditions were investigated. In this study, C. oleifera meal was firstly pretreated using mixed cultured Bacillus subtilis and Aspergillus niger under solid‐substrate fermentation to degrade the tea saponin (TS) for the following YW fermentation. Response surface methodology helped evaluate the effects of the selected operating parameters, and the optimal condition at a fixed time of 4 days, which gave a 67.84 ± 0.23% degradation rate of TS, was reached as inoculum concentration of 16%, initial moisture content of 55% and temperature of 30 °C. Finally, 7‐day fermentation was harvested to be the most suitable pretreatment for producing YW from C. oleifera meal, and the twice‐feeding fermentation for YW was obtained as wheat koji 12% and active yeast 1.2%. In addition, ample amino acids, phenolic components and the trace TS endowed the C. oleifera wine, the more nutritional characteristics.