醇化过程中白肋烟香味成分含量的变化

对醇化过程中白肋烟香味成分含量的变化进行了研究。结果表明 ,在醇化过程中白肋烟香味成分含量发生了明显变化。在所测定的 17种中性香味成分中 ,许多中性香味成分含量在醇化过程中呈明显增加趋势 ,增加幅度较大的成分有糠醛、糠醇、苯甲醛、苯乙醇、氧化异佛尔酮、巨豆三烯酮和金合欢基丙酮等。在所测定的 12种碱性香味成分中 ,有吡啶、2 ,3-二甲基吡嗪、2 ,5 -二甲基吡嗪、2 ,3,5 -三甲基吡嗪、四甲基吡嗪、2 -乙酰基吡啶等 6种重要碱性香气成分含量有明显增加 ,但碱性成分总含量在醇化过程中呈大幅下降趋势。     

组合积分系统在烟草工艺过程中的应用

烟草工艺过程中采用常规的PID控制算法或人工智能方法等,不能对组合积分系统进行有效控制,控制精度低,烘丝出口含水率仅能控制在±0.5%范围内,抗干扰能力差.基于模型预测控制的基本原理,设计了烟草工艺过程中组合积分系统的新型控制算法,分析了该算法的传递函数及特点.新控制方案在烘丝含水率控制过程中的应用表明,可以将出口含水率控制在±0.3%范围内,提高了控制精度;当总脱水量发生变化产生干扰时,仍能保证出口含水率的稳定.     

ACEROLA's CLONES OF INDUSTRIAL INTEREST

In order to know which clone of acerola is better for acerola industrialization, we studied the pectin methylesterase (PME) specific activity, pectin content and vitamin C content in five different clones of acerola. The pectin yield varied from 1.37 to 2.99% and the highest content of pectin occurred in clones 3 and 5. Ascorbic acid varied significantly from 1157.5 to 1735.5 mg/100 g of pulp in the five clones. The highest content of vitamin C occurred in clone 4. The PME specific activity varied from 0.79 to 2.92 units g ^?1 /g of pulp and the highest values occurred in clone 2. We also studied the optimum temperature and the optimum pH of this enzyme. Clones 1, 2, 4 and 5 showed optimum temperature at 90C. Clone 3 showed practically the same specific activity at all temperatures studied. Clones 1 and 4 showed an optimum pH of 9.0 and clone numbers 2, 3 and 5 showed a pH optimum at 8.5.     

Consumer acceptability and purchase intent of probiotic yoghurt with added glucose oxidase using sensometrics,artificial neural networks and logistic regression

This research aimed to identify the drivers of acceptance and purchase intent of a probiotic (Bifidobacterium longum BL05) nonflavoured yoghurt supplemented with glucose oxidase, and to model the consumers’ acceptability using sensometrics and artificial neural networks (ANN). Consumers (n = 100) evaluated the degree of liking of yoghurt assays in respect of appearance, aroma, taste, texture and overall linking. Sensometric techniques – multiple linear regression (MLR), partial least squares regression (PLS), principal component regression (PCR) – and ANN were used to model the overall liking. Sensory drivers of global acceptance and purchase intent were also determined using logistic regression (LR). Hierarchical cluster analysis (HCA) identified three consumer segments that presented differences in all sensory attributes evaluated (P < 0.05). The ANN model showed the best performance to predict overall liking, followed by the MLR, PLS and PCR, indicating that taste and texture were the most significant attributes impacting the yoghurts overall liking. In accordance with the logistic models, overall acceptance and purchase intent could be predicted with 81.94 and 85.49% accuracy, respectively. The logistic regression indicated that taste was the attribute that contributed significantly (P < 0.0001) to higher scores for purchase intent and was considered the driver of acceptance.     

CHARACTERIZATION OF STOMACH AND PYLORIC CAECA PROTEINASES OF TAMBAQUI (COLOSSOMA MACROPOMUM)

The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of crude extracts from the stomach, liver, pyloric caeca, and intestines of Colossoma macropomum were investigated. The highest acid and alkaline proteolytic activities were found in stomach and pyloric caeca, respectively. The optimum pH for the acid and alkaline proteases were 1.8 and 7.0–9.0, respectively, while the optimum temperatures were 35C and 65C. This alkaline protease thermal stability remained unaltered after 90 min incubation at 55C. A pepsin‐like protease was responsible for most of the acidic proteolytic activity (Pepstatin A inhibited approximately 90%), whereas PMSF inhibited about 40% of the alkaline protease. The alkaline proteolytic activity has attractive thermal properties for industrial applications.     

苯乙烯-丁二烯橡胶门尼黏度标准物质定值不确定度的评定

依照GB/T 1231.1-2000进行实验,利用JJF 1059-1999]对苯乙烯-丁二烯橡胶门尼黏度标准物质定值过程中的不确定度分量进行了分析和评定。该测定过程中所产生的不确定度主要由多家实验室测量重复性和定值样品均匀性、稳定性引入。定值样品苯乙烯-丁二烯橡胶SBR 1502的门尼黏度ML(1+4)100℃测量值49.1的不确定度为±0.8。     

河北大雀沟地区金成矿规律及找矿方向

河北省宣化—崇礼—赤城一带是冀西北重要的岩金产地,大雀沟地区位于该带东北部,近邻的大中型金矿床有黄土梁子、后沟、金家庄等。根据近年地质、物化探、槽探及钻探勘查成果,结合对该区金矿床地质特征、成矿规律进行的初步总结,认为矿床定位于碱性杂岩体的边缘构造夹持区,同时受到后期岩浆侵位影响;矿体严格受低次序构造控制,以脉状、透镜状就位于其中;钾长石化是该区最具特色的蚀变,矿石中金属硫化物含量偏低,属贫硫化物型。在此基础上,指出了进一步普查-详查的工作范围。     

Antioxidant Activity and Sensory Evaluation of a Rosmarinic Acid‐Enriched Extract of Salvia officinalis

An extract of Salvia officinalis (garden sage) was prepared using supercritical carbon dioxide (SC‐CO₂) extraction, followed by hot water extraction. The resulting extract was enriched in polyphenols, including rosmarinic acid (RA), which has shown promising health benefits in animals. The extract contained RA at a concentration of 28.4 mg/g, representing a significant enrichment from the RA content in sage leaves. This extract was incorporated into oil‐in‐water emulsions as a source of lipid antioxidants and compared to emulsions containing pure rosmarinic acid. Both treatments were effective in suppressing lipid oxidation. The extract was evaluated by a trained sensory panel in a tea formulation. While the panel could discriminate among extract‐treated and control samples, panelists demonstrated high acceptability of the sage extract in a tea.     

无机盐对木瓜蛋白酶凝固大豆分离蛋白凝胶的影响

为研究食品中常见无机盐对木瓜蛋白酶凝固大豆分离蛋白凝胶的影响,以大豆分离蛋白(SPI)为原料,测定添加NaCl、KCl、CaCl2、MgCl2和MgSO4等常见无机盐后木瓜蛋白酶凝固SPI的时间、凝胶质构、凝固过程中pH值及蛋白质降解程度的变化。结果表明：添加一定浓度的无机盐可以缩短凝固时间并提高凝胶强度。相同离子强度下,Ca2+和Mg2+对凝固时间及凝胶强度影响均大于Na+和K+。添加无机盐可使SPI的pH值降低,加酶后pH值再次持续下降,但一定时间后趋于稳定。无机盐的种类和浓度对木瓜蛋白酶凝固SPI过程中蛋白质降解程度影响不明显。SPI中CaCl2的离子强度为15(CaCl2浓度为5mmol/L)时,将酶添加量从0.15%减少到0.1%,可使凝胶强度提高60%。因此,添加适量的一价及二价无机盐可显著缩短酶凝固时间并提高凝胶强度。添加Ca2+和Mg2+等二价阳离子盐类是提高木瓜蛋白酶凝固大豆蛋白凝胶强度的有效途径。