Effect of microwave pretreatment on the color degradation kinetics in mustard greens (Brassica juncea)

In the present work, the impact of microwave pretreatment on the thermal degradation of color (chlorophylls) in mustard greens was studied. The drying experiments were conducted in the range of temperatures from 50 to 80°C. The degradation in the levels of chlorophylls has been quantified using Hunter color values (L*, a*, and b*) and calculating total color difference (ΔE). From the color results, the changes in color values (L*, a*, and b*) were observed as inappreciable, and changes in ΔE were found to be increased during drying. Analysis of kinetic data displayed a first-order reaction kinetics for chlorophyll degradation. Arrhenius equation was used to calculate the activation energies for rate constants, and it has been varied from 13.3 to 27.4?kJ/mol. Thermodynamic parameters, enthalpy of activation (ΔH^#), and entropy activation (ΔS^#) were found to be in the range of 1.40–2.63?J/mol and ?293 to ?305?J/mol?·?K, respectively. The data from the present work revealed that the microwave pretreatment of mustard greens remarkably influenced the retention of chlorophylls in the final dehydrated powder.     

Recovery of allyl isothiocyanate from steam distillation condensate using adsorption

This paper describes the results of a study on use of the adsorption–regeneration technique for recovery of dissolved allyl isothiocyanate(AITC) which is present in significant quantities in steam distillation condensate of mustard essential oil (MEO). Equilibrium and dynamic breakthrough studies were carried out. The adsorbents used were polymeric adsorbents: Amberlite XAD‐2, Amberlite XAD‐4, Amberlite XAD‐7, NPA‐1 and NPA‐2. The results obtained indicate that Amberlite XAD‐4 is the best amongst these various adsorbents. AITC recoveries in excess of 95% were obtained, indicating the feasibility of this approach. Further, since no chemical reactions are involved the recovered AITC retains its ‘natural’ origin. © 2000 Society of Chemical Industry     

Nutritional effects of mustard seed protein detoxified with aqueous isopropanol in young rats

The effect of removing anti‐nutritional factors from n‐hexane‐extracted mustard meal using 80% isopropanol (to reduce thioglucosides, phenolics, etc.) on growth, food efficiency ratio, serum and liver lipid profiles and protein content of young rats was examined. For this n‐hexane‐extracted mustard meal was extracted with 80% isopropanol giving a fraction with 68% protein and low residual thioglucoside (0.5%) as well as phenolic (0.3%) content. This isopropanol‐extracted mustard seed protein fraction reduced the growth of young rats slightly when compared with casein. The food efficiency ratio between rats fed isopropanol‐extracted mustard seed protein or casein did not differ, nor did the protein composition affect serum total cholesterol, triglyceride, HDL‐cholesterol, LDL‐cholesterol, VLDL‐cholesterol and LDL‐C/HDL‐C ratio. However, rats fed isopropanol‐extracted mustard seed protein showed a significantly lower (p<0.05) liver cholesterol concentration than rats fed casein. Liver triglyceride and phospholipid concentrations did not differ between rats fed the two proteins, nor was serum protein affected. This study indicates that extraction of hexane‐extracted mustard meal with 80% isopropanol reduced a number of anti‐nutritional factors like thioglucoside and phenolics. Furthermore the nutritional quality of mustard seed protein fraction is comparable to casein in respect to growth, food efficiency ratio, serum lipid and protein concentrations and organ weights.     

Mechanical and Transport Properties of Poly(ethyleneterephthalate) Films with Reference to Sulphur Mustard

Influence of sulphur mustard (SM), a chemical warfare agent, on mechanical and transport properties of poly(ethyleneterephthalate) (PET) films was investigated. The objective of the study was to assess the agent–substrate interaction. SM induces changes in PET in that the elongation as well as strength of SM-exposed films decreases considerably. The reduction in percentage elongation at break is very significant, perhaps because of the antiplasticizing effect of SM on PET. The breakthrough time (BTT) of SM is higher for the film, which showed greater resistance to amine etching. The critical dissolution time measurement substantiates the data on mechanical behaviour of SM-exposed films. © of SCI.     

包装方式对榨菜品质和保藏特性的影响

以三腌完成的榨菜为原料,加入辣椒、花椒、糖、食用油等进行调味,选用透明（塑料袋）真空包装、不透明（铝箔袋）真空包装、透明充氮包装和不透明充氮包装4 种方式对成品榨菜进行包装。对室温（25 ℃）条件下保藏的榨菜进行品质和保藏特性的研究。结果表明：在75 d保藏期内,透明包装的褐变度、总酸含量、亚硝酸盐含量、菌落总数要高于不透明包装,透明包装的色泽、硬度、感官均低于不透明包装;充氮包装榨菜的硬度、总酸含量、感官评价高于真空包装,褐变度和菌落总数低于真空包装。不透明充氮的各项指标均优于其他包装方式,可以较好地保持榨菜的品质。     

多电极复合法快速测定榨菜食盐含量

建立一种基于多电极复合的榨菜食盐快速测试方法。首先设计制作由离子选择电极、温度传感器、参比电极、信号处理模块、单片机模块等组成的多电极复合系统硬件,然后建立钠离子、氯离子预测模型以及数据处理软件程序,最后使用该系统对3 种涪陵榨菜进行食盐测定,并与传统测试法进行对比。结果表明,多电极复合法与传统法测定结果的平均相对误差小于5%,相对标准偏差小于2.0%,t检验结果无明显差异;单次测试时间小于20 s,该方法可作为榨菜食盐测定的快速方法。     

Survival of E. coli O157:H7 during manufacture of dry‐cured Westphalian ham surface‐treated with allyl isothiocyanate or hot mustard powder

BACKGROUND: Escherichia coli O157:H7 can survive commercial manufacture of some uncooked fermented meats. External application of microencapsulated allyl isothiocyanate (AIT) or hot (non‐deheated) yellow mustard powder was used to inactivate the pathogen during dry‐cured Westphalian ham manufacture. RESULTS: Within 45/80 days, E. coli O157:H7 numbers were reduced 5 log₁₀ CFU g^?1 by 400 µg kg^?1 AIT or 60 g kg^?1 mustard powder, but 80 days were required in the untreated control. Mustard powder but not AIT reduced numbers of lactic acid bacteria and staphylococci. Mustard powder or ≥ 300 µg kg^?1 AIT inhibited yeasts and moulds but did not affect ham pH or water activity. CONCLUSION: The commercial Westphalian ham process without AIT or mustard powder treatment was validated capable of reducing E. coli O157:H7 5 log₁₀ CFU g^?1. Surface treatments with ≥ 300 µg kg^?1 microencapsulated AIT or 60 g kg^?1 yellow mustard powder reduced the time required for this reduction by 40–50%. AIT volatility from microcapsules or hot mustard powder during application of these compounds may restrict their use in production facilities. Copyright © 2009 Society of Chemical Industry     

接种发酵对酸菜品质的影响

以青菜为原料,选用鼠李糖乳杆菌、嗜酸乳杆菌和发酵乳杆菌3种乳酸菌进行人工接种试验,设计了7个配方,发酵时间为8d,研究发酵菌种对酸菜总酸含量和亚硝酸盐含量的影响,确定最适合酸菜发酵的菌种,并研究接种发酵对酸菜的氨基酸含量和挥发性风味物质成分的影响。结果表明,当鼠李糖乳杆菌、嗜酸乳杆菌和发酵乳杆菌的比例为1:1:1时,酸菜总酸含量升高最快,亚硝酸盐含量最低且无明显的亚硝峰出现,为最适合酸菜发酵的菌种。接种发酵酸菜的氨基酸种类和含量均高于自然发酵的酸菜,挥发性风味物质成分的种类和相对含量均低于自然发酵的酸菜。     

襄阳大头菜腌制液膜醭细菌群落结构研究

使用Miseq高通量测序技术对3个襄阳大头菜腌制液膜醭样品的细菌微生物群落结构进行了解析。在门水平上,变形菌门（Proteobacteria）和硬壁菌门（Firmicutes）平均含量分别为62.12%和34.13%。在属水平上,相对含量＞1.0%的细菌属分别为盐单胞菌（Halomonas）、色盐杆菌属（Chromohalobacter）、海杆菌属（Marinobacter）、盐厌氧菌属（Halanaerobium）、四联球菌（Tetragenococcus）和碱杆菌属（Alkalibacillus）,其相对含量为26.31%、16.49%、8.13%、24.87%、6.13%和1.16%。在操作分类单元水平（OTU）上,发现14个平均相对含量＞1.0%的核心OTU,其中OTU4083（隶属于盐厌氧菌属）、OTU4400（隶属于色盐杆菌属）和OTU846（隶属于盐单胞菌属）的累计平均相对含量为39.50%。由此可见,襄阳大头菜膜醭中的细菌微生物主要由隶属于变形菌门和硬壁菌门的6个属构成,且膜醭共有大量的核心细菌菌群。