基于VFD-E变频器的智能炒茶机设计

参照信阳毛尖手炒茶工艺,采用内置PLC(programmable logic controller)的VFD-E变频器,设计了一种智能炒茶机控制系统.在茶叶翻炒过程中,该系统以一定的时间间隔实现翻炒方向的切换,并实时采集茶叶的加热温度,送入变频器的模拟量通道,直接输出相应的频率值,控制炒茶电机的转速,实现了手炒茶工艺的模拟.     

The enzymatic hydrolysis of used frying oil by native lipase

The enzymatic hydrolysis of used frying oil catalyzed by native lipase ofNigelk sativa seed was investigated under different conditions to elucidate the role of different process parameters on the reaction rate. Data fitted the first-order rate equation.     

闽西客家特色捶鱼饼真空油炸最佳工艺研究

将真空油炸技术应用于闽西客家特色捶鱼饼的加工。以淡水鱼中的鲜活草鱼为原料,在研究其真空油炸时的工艺学特性基础上,优化主要工艺条件参数,所选出的最佳工艺条件为:真空度-0.08 Mpa、油炸温度105℃、油炸时间21 min,油炸后配合离心脱油处理,转速300rpm、时间66 s。应用该条件并结合闽西客家捶鱼饼的传统预处理工艺,所开发的产品色泽金黄、炸鱼香味浓郁、酥脆爽口、破碎率5.73%、含油量≤45 g脂肪/100 g、普通包装在室温条件保质期可达12个月,综合品质明显优于闽西客家传统捶鱼饼。     

低场核磁共振法快速检测炸油质量

由于在高温油炸过程中的快速劣变,市场上油炸用油的质量问题日益受到人们的关注. 为了研究低场核磁共振技术在市场上复杂油炸条件下的油炸用油质量快速检测中的表现,共从上海市10个行政区的市场上共采集油炸用油样品107个,包括大豆油96个,起酥油11个. 通过测定油样的极性组分和黏度,发现6个(占总样品数56%)油样的极性组分超过国家标准,说明市场上油炸用油存在一定的安全问题. 通过线性分析发现极性组分和黏度之间的线性关系良好,R2为0892,除去样品中11个起酥油后R2则达到0927. 用低场核磁共振仪测定各油样后,通过对多组分T2弛豫图谱中T21峰面积(S21)比例的分析发现,S21比例与极性组分和黏度呈现良好的相关性,R2值分别为0860和0840,除去油样中的起酥油后R2值略有上升,分别达到0865和0854. 这说明可以利用低场核磁共振技术达到快速检测市场上油炸用油品质的目的.     

Effects of Green Tea Marinade in the Bioaccessibility of Tonalide and Benzophenone 3 in Cooked European Seabass

Fish consumption is an indicator of human exposure to personal care products (PCP) such as tonalide (AHTN) and benzophenone 3 (BP3). Although most fish consumed is cooked, the impact of cooking procedures on PCP levels is difficult to evaluate. Hence, the aim of this work was to provide thorough information on the stability and bioaccessibility of AHTN and BP3 upon cooking and in vitro digestion. A green tea (Camellia sinensis) marinade, rich in polyphenol, was used as mitigating strategy to reduce these contaminants. Roasting and frying reduced AHTN and BP3 levels in European seabass (Dicentrarchus labrax) spiked samples. Additionally, the green tea marinade promoted a reduction of up to 47% AHTN and 35% BP3. Bioaccessibility of AHTN was higher (up to 45%), and increased with the use of green tea marinades. BP3 showed a bioaccessibility below 19% in all cooked samples. Overall, a decrease in PCP levels was observed after cooking; this decrease was even more pronounced when marination was previously used. However, this decrease is cancelled out by the fact that the bioaccessible fraction of the contaminants increases in an inverse way; therefore, none of these processes can be considered a mitigating alternative.     

小茴香不同炮制品活性成分的动态变化研究

按《中华人民共和国药典》分别对净制后的小茴香进行清炒、盐制、醋制、酒制和姜汁制,并提取出活性挥发油,采用气相色谱-质谱联用仪和薄层色谱对提取物进行分析。小茴香经不同辅料炮制后挥发油含量显著降低;与生品相比,炮制品均含有相同的主要活性成分,其中反式-茴香脑含量最高,顺式-番桧烯水合物、顺式-罗勒烯、α-松油烯、4-松油烯、对位-烯丙基茴香醚和枯敬醛为首次在小茴香药材中检测到;鉴定出的24种化合物经不同方法炮制后含量均发生了明显变化,且发生了相应的转化,这是导致不同炮制品具有不同药性和功效的重要原因。     

Effects of low-frequency ultrasonic pre-treatment in water/oil medium simulated system on the improved processing efficiency and quality of microwave-assisted vacuum fried potato chips

The effects of low-frequency ultrasonic pre-treatment in water/oil medium simulated system on the improved processing efficiency and quality of microwave-assisted vacuum fried potato chips were investigated. The water medium system (distilled water and 5% NaCl osmotic solution) and oil medium system (90 °C) were designed with different power levels of ultrasound to simulate the ultrasonic conditions. Results showed that the changes of moisture content, water loss, solid gain and dielectric properties of potato slices were facilitated by the ultrasonic treatment. LF-NMR analysis showed the binding force between the moisture and structure in the material was significantly (p < 0.05) weakened. The changes become greater with the increase of ultrasonic power levels. Microscopic channels and disruptions were induced on the microstructure by the ultrasonic treatment. The effective moisture diffusivity of vacuum fried (VF) potato chips was increased by about 56.2%-67.0% and 53.9% with the combination of microwave energy and the ultrasonic pre-treatment in water and oil medium simulated system, respectively. The oil uptake, hardness, shrinkage, total color change and water activity of vacuum fried samples were significantly (p < 0.05) decreased by the assist of microwave energy combined ultrasonic pre-treatment.     

Monitoring tert-Butylhydroquinone Content and Its Effect on a Biolubricant during Oxidation

The use of biolubricants as a replacement for petroleum-based products is becoming more and more important, due to the current global energy and crude oil scenario. Thus, the production of biolubricants (which could take place in biorefineries) should be as efficient as possible, obtaining high-quality products with suitable viscosity or oxidation stability values to compete with oil refineries. One of the ways to produce biolubricants is through double transesterification from vegetable oils, where the role of catalysts (usually homogeneous) is vital, as they can improve the yield of the process. However, they should be removed after the chemical reaction, which is difficult once the biolubricant is obtained. Otherwise, they could act as catalysts during oxidation, contributing to a further decrease in oxidation stability and provoking significant changes. To avoid this, antioxidant addition could be an interesting choice. The aim of this work was to assess TBHQ addition in frying oil biolubricants, monitoring properties such as viscosity, acid number, absorbance or TBHQ content (through voltammetry) during oxidation. TBHQ addition (2114 mg·L⁻¹) kept the main quality parameters during oxidation compared to control samples. In contrast, TBHQ content decreased during oxidation (to 160 mg·L⁻¹), which proved its antioxidant effect.     

滑炒滑溜最佳工艺的初步研究

分析了菜肴制作的整个工艺流程,对其上浆、醒浆、油温、划油时间四个关键步骤作了进一步分析。通过正交试验法得到最佳工艺条件,研制后的成品无论从体积、形状、色泽、质感和营养成分上均有明显的提高。这些数据为菜肴最佳工艺的研究提供了依据。     

The use of high performance liquid chromatography for the quality survey of frying fats and oils

Summary During the process of deep fat frying the frying fat or oil undergoes complex chemical reactions which lead to its deterioration. For the quality survey of frying fats or oils the time-consuming determination of total polar components by column chromatography is an approved standard method. High performance liquid chromatography (HPLC) can be used to substitute this technique. Moreover, HPLC proved to be a useful tool for the determination of the qualitative and quantitative composition of fatty acid and polar substances which change during the frying process. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996