脂类物质与肉的风味

本文主要阐述了肌肉中脂类物质水解,氧化的机理,脂肪氧化与美拉德反应相互作用,及其对肉类风味形成的贡献.     

发酵肉制品常见微生物及其对风味的影响

介绍了发酵肉制品中常用微生物的种类、性质、作用以及常用的微生物发酵剂,探讨了微生物在发酵过程中形成的风味物质及其对肉制品风味的影响.     

浙大中药指纹图谱相似度计算软件在烟用香精香料色谱分析中的引入应用

系统地介绍浙大中药指纹图谱相似度计算软件五个基本功能:1.数据导入,2.数据预处理和色谱图的缩放比较,3.保留时间校正和谱峰自动匹配,4.指纹图谱相似度计算,5.结果输出和报表打印。浙大中药指纹图谱相似度计算软件为一种简便易学的软件系统,就其操作中的关键问题给予图文结合的方式加以详细说明。通过香精色谱分析的例子,对峰点的校正匹配与整体相似度计算等其它功能作进行详细讲解。     

陇南两种单品种初榨橄榄油的化学性质和脂肪酸组成随成熟度的变化

分析了陇南2个品种初榨橄榄油的化学性质和脂肪酸组成随成熟度增加的变化规律。结果表明：随着成熟度的增加2个品种的鲜果出油率增加且存在显著性差异。初榨橄榄油风味成分中氮氧化合物、含硫以及烷烃类化合物变化幅度较大,通过电子鼻可以区分不同品种不同成熟度的橄榄油。恩帕特雷和科拉蒂的k232、270值最高分别为1.85和1.91、0.18和0.14,多酚、黄酮含量变化范围分别为2.39～4.53和7.47～10.39、0.07～0.40和0.75～2.84 mg/g。氧化稳定时间在第6（6.28 h）和第5(16.71 h)成熟度为最高。酸价的变化范围分别为0.37～1.02和0.19～0.38 mg/g,过氧化值的变化范围分别为2.92～8.32和2.38～5.19 mmol /kg,油酸含量分别为72.36%～77.76%和59.23%～65.73%,亚油酸含量分别为7.70%～11.81%和9.74%～15.86%,SFA含量分别为11.81%～13.15%和14.25%～20.99%,PUFA含量分别为8.34%～12.36%和10.92%～16.84%,MUFA含量为72.69%～78.50%和62.36%～68.20 %。同一品种的MUFA/PUFA、C18:1/C18:2和MUFA含量变化趋势一致,与PUFA呈相反的变化趋势,2个品种之间各种脂肪酸含量差异明显,上述测定指标完全符合GB 23347—2009中特级初榨橄榄油的标准。科拉蒂的出油率、多酚、黄酮、油酸含量和氧化稳定时间明显大于恩帕特雷,而酸价、过氧化值低于后者。综合考虑认为科拉蒂的初榨橄榄油品质优于恩帕特雷,恩帕特雷和科拉蒂分别在第6和第5成熟度的初榨橄榄油品质最好。     

2,3-二甲基喹噁啉的合成研究

用邻苯二胺和２,３－丁二酮在苯溶剂中缩合脱水,合成了２,３一二甲基喹啉,产率达到７５．３％,而且产品易于精制纯化,产品质量高,用ＵＶ、ＩＲ和’ＨＮＭＲ鉴定了结构。     

Optimization of the enzymatic production of isoamyl acetate with novozym 435 from candida antarctica

In this study the production of isoamyl acetate by esterification of isoamyl alcohol and acetic acid was carried out using immobilized C . antarctica lipase (Novozym 435) as a catalyst without any organic solvent. The esterification yield was optimized with response surface methodology. This method was used with four parameters to evaluate the effects of important variables on the esterification yield. The parameters are acid/alcohol mole ratio (0.2-0.8), enzyme amount (4-12%, w/w), temperature (30-50 °C), and reaction time (4-8 hr). It was found that the most effective parameter was acid/alcohol mole ratio. As acid/alcohol mole ratio increased at any given reaction time and amount of enzyme, ester concentration, C p (mmol ester/g mixture), increased up to an acid/alcohol mole ratio of 0.7 and thereafter decreased. The model indicated the optimum conditions for maximum esterification (3.45 mmol ester/g mixture) in the acid/alcohol mole ratio of 0.52 for 8.15% enzyme at 43.2 °C and after 5.27 hr, which were in good agreement with the experimental value (3.5 mmol ester/g mixture).     

Influence of Spray-Dryer Air Temperatures on Encapsulated Mandarin Oil

The influence of inlet and exit air temperatures (160–200 and 80–100°C, respectively) on the spray drying of mandarin oil was evaluated by using a three-level factor design. For optimization, dryer evaporative rate, volatile oil retention, and microencapsulation efficiency were considered as response variables. The response surface analysis produced significant (p < 0.05) polynomial regression equations that were successfully fitted for all response variables and no significant (p > 0.05) lack of fit was indicated for the reduced models. This observation confirmed an accurate fitness of the reduced response surface models to the experimental data. The multiple response optimizations indicated that an inlet air temperature of 200°C and an exit air temperature of 80°C were predicted to provide the maximum evaporative rate, volatile oil retention, and microencapsulation efficiency in the studied ranges.     

Mid-Oleic/Ultra Low Linolenic Acid Soybean Oil: A Healthful New Alternative to Hydrogenated Oil for Frying

To determine the frying stability of mid-oleic/ultra low linolenic acid soybean oil (MO/ULLSBO) and the storage stability of food fried in it, tortilla chips were fried in MO/ULLSBO, soybean oil (SBO), hydrogenated SBO (HSBO) and ultra low linolenic SBO (ULLSBO). Intermittent batch frying tests were conducted up to 55 h of frying, and then tortilla chips were aged up to 4 months at 25 °C. Frying oils were analyzed for total polar compounds to determine the frying stability of the oil. Tortilla chips were analyzed for hexanal as an indicator of oxidative deterioration and by sensory analysis using a trained, experienced analytical panel. Results showed no significant differences between the total polar compound levels for MO/ULLSBO and HSBO after 55 h of frying, indicating a similar fry life. However, total polar compound levels for ULLSBO and SBO were significantly higher than for either MO/ULLSBO or HSBO, indicating a lower oil fry life. Hexanal levels in aged tortilla chips fried in SBO were significantly higher than in chips fried in any of the other oils. Tortilla chips fried in MO/ULLSBO and HSBO had significantly lower hexanal levels than in chips fried in ULLSBO. A sensory analysis of rancid flavor intensity showed similar trends to those for hexanal formation. The chips fried in SBO had the highest rancid flavor intensity, with significantly lower hexanal levels in chips fried in HSBO and MO/ULLSBO. Based on these results, MO/ULLSBO not only had a good fry life but also produced oxidatively stable fried food, and therefore would be a healthful alternative to HSBO. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable.