SIMULATION STUDIES OF THE REMOVAL OF WATER FROM ETHANOL BY A CATALYTIC DISTILLATION PROCESS

A new approach based on catalytic distillation (CD) technology was proposed to remove water from ethanol. Isobutylene was introduced to react with water in the CD column. The commercial software simulation tool Aspen Plus was used to investigate the effects of key design factors such as operating pressure and temperature, reactant ratios, reflux and distillate to feed ratios, number of separation and reaction stages, and feed and reaction zone location. It was found that the CD technology offers potential advantages of reduced energy consumption and reduced capital cost over traditional approaches for the removal of water from ethanol.     

TBARs distillation method: Revision to minimize the interference from yellow pigments in meat products

The aim was to study the effect of the incubation method and TBA reagent (concentration/solvent) on yellow pigment interference in meat products. Distillates from red sausage, sucrose, malondialdehyde and a mixture of sucrose–malondialdehyde were reacted with four different TBA solutions at five different temperature/time relations. Two TBA solutions were prepared at 20 mM using 90% glacial acetic acid or 3.86% perchloric acid. In addition, an 80 mM TBA solution was prepared using distilled water adjusted to pH 4 and another using 0.8% TBA in distilled water. The temperature/time relations were: (1) 35 min in a boiling water bath; (2) 70 °C/30 min; (3) 40 °C/90 min; (4) room temperature (r.t.) (24 °C) in dark conditions for 20 h; and (5) 60 min in a boiling water bath. The results showed that aqueous or diluted acid solutions of TBA reagent and the application of 100 °C for less than 1 h provided the best conditions to minimize the presence of yellow pigments and maximize pink pigment formation in meat products.     

啤酒强制老化过程中SO2、抗氧化力与TBA值的相关性研究

研究了啤酒强制老化过程中二氧化硫含量、抗氧化力评价指标与TBA值之间的相关性。Person相关性分析表明:二氧化硫含量与DPPH自由基清除活性、ABTS自由基阳离子清除活性、还原力和金属螯合性之间有显著的正相关性,TBA值与抗氧化评价指标及二氧化硫含量之间呈显著的负相关性。逐步回归分析表明:提高啤酒中DPPH自由基清除活性可以抑制啤酒老化的TBA值,对TBA的抑制力达到97.7%。     

Chemical quality and sensory attributes of marinated Pacific saury (Cololabis saira) during vacuum-packaged storage at 4 °C

This study was carried out to evaluate the chemical changes and sensory attributes of Pacific saury (Cololabis saira), brined (12% NaCl brine solution) or marinated (12% NaCl + 2% acetic acid; or 12% NaCl + 3% acetic acid solutions) followed by vacuum-packaging and storage at 4 °C for 90 days. The chemical analysis revealed a significant reduction in the pH value, total volatile bases nitrogen (TVBN), and trimethylamine (TMA) contents in marinated versus brined fillets. Lipid oxidation, as indicated by the 2-thiobarbituric acid (TBA) values, was significantly delayed in marinated fillets in comparison with the brined fillets. The growth rate of psychrotrophic bacteria was significantly (P < 0.05) reduced in marinated versus brined fillets. No significant differences were detected for the sensory attributes between the two marinating conditions although the overall acceptability was significantly higher in marinated versus brined fish. Both conditions of the marinating process resulted in an extension of the shelf life of the product to more than 90 days versus only 60 days for the control brined fillets. The study concluded that marination of Pacific saury can delay the undesirable chemical changes, retard lipid oxidation, improve the sensory attributes and extend the shelf life of the product during refrigerated storage.     

The sensory quality of foods produced by conventional and enhanced cook-chill methods

Cook-chill systems are now widely used within the catering industry. The basic method has been enhanced by the use of vacuum packaging to extend shelf-life; and, it is claimed, sensory quality. This paper reviews the literature available on the sensory quality of foods produced by conventional and enhanced cook-chill methods. It shows that the sensory quality of foods produced by these methods has received little attention from researchers, despite, in the case of methods using vacuum packaging, some extravagant claims about improved eating quality. Most attention has been paid to meat products. Deteriorative changes are shown to occur rapidly, but many variables affect the end result, which is often product and process specific. Lack of standardization, both in the catering industry and in experimental methods, makes comparisons between studies difficult.     

回旋沉淀槽停留时间对麦汁质量的影响

回旋沉淀槽的作用主要是分离麦汁中的热凝固物和酒花糟等，麦汁在回旋沉淀槽里停留的时间长短会影响麦汁的质量。该文通过检测麦汁的TBA、色度和浊度等质量指标，确定麦汁在回旋沉淀槽内静置20min，停留时间在60min内是合适的，此时麦汁的质量最好。     

Effect of processing methods on product characteristics,lipid, fatty acid composition and oxidative stability of smoke-dried beef

Smoke-dried beef was pre-processed with water or by pressure cooking, weight losses were 50 and 54% respectively, with the rate of drying faster in the latter. There was a greater loss of total lipid and triglycerides in pressure cooked samples but the reverse was true for the phospholipids. The proportions of saturated and monoenoic fatty acids were slightly higher in the water cooked products although total unsaturation was slightly lower, the values being 37 and 39%, respectively. The fatty acid composition of the phospholipids was similar for both treatments except that the levels of polyenoic fatty acids were 16.4 and 14.43%, respectively in water and pressure cooked samples. Of the polyenes C20:4 accounted for about 75% of the fatty acids in the water cooked samples, compared with 40% with pressure cooking. After 60 weeks of storage at room temperature, pressure cooked samples were found to be more stable oxidatively: malonaldehyde was the principal oxidative by-product in both treatments.     

外交联型聚丙烯酸酯固化行为研究

利用动态力学扭瓣分析研究了聚丙烯酸酯的升温固化过程，提出了一种两步固化机理，并求算得到了体系的固化活化能，发现有机晚催化剂有能有效降低固化活化能并讨论了其催化历程。     

丙烯酸酯乳胶低温固化的研究

用动态扭辫分析法（ＴＢＡ），研究了丙烯酸酯乳胶与四羟甲基甘脲的固化行为。结果表明，含交联剂的丙烯酸酯共聚乳胶和共混乳胶，其固化温度在８０￣１１７℃之间。其乳液用阳离子交换树脂处理或外加酸催化剂，固化温度会更低。本文还研究了交联剂对固化温度和分子运动的影响。用等温固化过程测定乳胶的表观固化活化能，约１０ｋＪ／ｍｏｌ，均表明甘脲型交联剂是一种优良的低温固化剂。     

Influence of γ-irradiation and ice storage on fat oxidation in three Indian fish

The influence of low-dose γ-irradiation (up to 5 kGy) on fat oxidation in skin and flesh fractions of some commercially important fishes (Indian mackerel, white pomfret and seer) during ice storage was examined. Thiobarbituric acid (TBA) values increased in both control and irradiated fish particularly in mackerel and seer meat. In mackerel, the TBA values declined towards later part of storage. Pomfret skin, but not mackerel and seer skin, showed radiation-induced oxidation, which increased further during ice storage.