Fresh plant tissue softening by means of an immobilized soluble-insoluble endopectinlyase

An endopectinlyase (E.C. 4.2.2.10) immobilized on a reversible soluble-insoluble polymer was used for macerating fresh carrot tissue. the macerating capability of the immobilized enzyme was found to be similar to that of its free form. Losses of catalytic activity detected in the subsequent biocatalyst utilization cycles seem to be related to co-precipitation phenomena following the recovery of the immobilized enzyme from the reaction mixture. Preliminary studies were carried out on the possibility of removing the inhibiting compounds and subsequently restoring biocatalyst activity.     

Etude des facteurs d'intensification de l'échange de chaleur dans le refroidissement des fruits et légumes

Increasing the rate of fruit and vegetable cooling is of economic significance for the following reasons: biochemical and microbiological processes are quickly suppressed; surface mass-exchange with ambient air is slowed down; power consumption is reduced, and the freezing output of cooling equipment and installations is increased.It was assumed that the fruits and vegetables in crates were arranged regularly and covered with thin paper of a negligible small thermal resistance in order to eliminate the infiltration of cold air within the layers. Crates were arranged on a pallet so that they touched horizontally. Thus, the packages form plates above and below the cooling air flow. Heat-exchange with a one-dimensional temperature field is established.It was found that intensification of cooling can be achieved by increasing the speed of cooling air as well as by stopping the process at a higher final temperature. Increasing the speed up to 5 m s⁻¹ shortens the time of the process by a factor of two compared with the low speeds (0.3–0.5 m s⁻¹) which are normally used. The product can be cooled until the temperature in the layer centre reaches 5°C, and the surface temperature about 2°C, which is low enough. Afterwards the cooled product is transferred to a freezing chamber or to a van-freezer. This factor results in a further halving of the cooling time. The combined effect of the two factors shortens the duration of the process by about 75% and increases the output of the cooling equipment from 3.5 to 4 times.     

一种新型无毒易溶酸洗缓蚀剂的研制

以几种植物（Ｈｈ，Ｈｂ，Ｂ，Ｙ，Ｍ）为原料的单，复配方，对碳钢在５％ＨＣｌ溶液中的缓蚀效果进行了试验，并对缓蚀剂机理进行了初步探讨。     

Emulsion multiple de type L/H/L: étude de l'obtention et du mécanisme de libération

Une émulsion multiple L/H/L contenant de l'huile d'amande douce en phase interne et de la paraffine liquide légère en phase externe a été mise au point. Pour cette étude, la nature de l'émulsionnant primaire puis le taux et la nature de l'émulsionnant secondaire ainsi que le pourcentage de l'émulsion primaire à disperser pour l'obtention de l'émulsion multiple, ont été optimisés. Le rôle de chacun de ces constituants a été envisagé dans la stabilisation de l'émulsion multiple ainsi que celui des différents additifs ultérieurement introduits. La différence de nature chimique entre les phases huileuses externe et interne et l'introduction de traceurs ont permis de suivre la stabilité de l'émulsion dans le temps et d'appréhender le mécanisme de libération de substances actives dans ce type de système, par dosages chromatographiques de l'acide oléique et de la vitamine E dans la paraffine liquide légère. Le taux de vitamine E libéré est inférieur à celui de l'acide oléique. Ce phénomène s'explique par une rétention de la vitamine E dans le réseau formé par les tensioactifs polymériques utilisés. La libération apparait done essentiellement provenir de l'éclatement des globules aqueux.
Multiple emulsion of oil in water in oil type: preparation and breakdown mechanisms     

Practical experiences of sensory investigations into the packaging of vegetables

The market for modified atmosphere foods continues to grow throughout Europe. This paper highlights some of the practical research studies carried out at the Campden Food and Drink Research Association during recent years. Vegetables referred to include potatoes, mushrooms, Brussels sprouts, calabrese, carrots, bean sprouts, watercress, diced onions, lettuce and mixed lettuce, and mixed vegetables. In all cases sensory evaluations of appearance were carried out on these vegetables packed in different atmospheres and in different packaging films, but only some results are included here in detail. Reference is made to a new industry guideline document for the good manufacturing and handling of modified atmosphere packed food products, and also to the use of active packaging.     

Utilisation of fruit and vegetable wastes in layers' diet

Improvement in egg production and egg size was noted when dietary rice polishing was replaced by carrot residue at 80 g kg^?1 diet. The layers fed on a diet containing orange waste or mango peels showed results comparable with the control. Egg production and egg size were adversely affected when mango stone was added to the layers' diet.     

全自动固相萃取净化-高效液相色谱法测定食用植物油中苯并(a)芘含量

为提高工作效率,降低误差,建立分子印迹柱全自动固相萃取净化-高效液相色谱法测定食用植物油中苯并(a)芘含量的方法。样品经正己烷提取,采用全自动固相萃取仪进行分子印迹柱净化,C18色谱柱分离,高效液相色谱-荧光检测器检测。结果表明：苯并(a)芘在0.5～20.0 ng/mL质量浓度范围内与峰面积线性关系良好,相关系数为0.999 9,方法检出限为0.09μg/kg,定量限为0.30μg/kg,加标回收率为91.7%～111.8%,相对标准偏差为2.0%～8.2%,与国标方法的检测结果不存在显著性差异;对市售38份食用植物油样品进行检测发现,苯并(a)芘的检出率为76.3%。该方法准确度高、重复性好,可批量自动化前处理样品,提高工作效率,并降低人员操作误差风险,适用于食用植物油中苯并(a)芘含量的测定。     

基于嗅觉可视化技术的食用植物油分类识别

为实现山茶油与3种常见食用植物油(菜籽油、大豆油和玉米油)的区分,制备可视化传感器阵列,采用嗅觉可视化技术对4种不同种类的食用植物油进行分类识别。采用主成分分析(PCA)对4种油样的特征数据进行降维,然后将降维后的数据导入K近邻(KNN)、极限学习机(ELM)、支持向量机(SVM) 3种分类模型中进行模型参数优化,对比了3种分类模型的分类结果。结果表明：建立的SVM分类模型性能最优,当输入主成分向量数为7、c=1.741 1、g=4.549 8时,SVM分类模型的测试集分类识别准确率为95.8%,五折交叉验证准确率为89.6%。制得的可视化传感器阵列可以实现4种食用植物油的分类识别,嗅觉可视化技术用于食用植物油检测是可行的。     

蔬菜汁/粉替代亚硝酸盐在肉制品加工中的应用

蔬菜汁/粉营养丰富,亚硝酸盐含量极低,硝酸盐含量较高。添加蔬菜汁/粉可使肉制品获得腌肉特有品质,提高肉制品营养价值,有助于功能性肉制品的研发。本文主要概述了蔬菜汁/粉在肉制品加工中的应用及使用中应注意的问题。     

顶空固相微萃取气质联用分析泡椒凤爪的香气成分

采用顶空固相微萃取结合气质联用分析了泡椒凤爪的挥发性香气成分,共检出21种香气成分,其中酚类6种、酸类5种、酯类4种、醛类3种、其他3种。检测到的含量较高的化合物有对丙烯基苯甲醚、乙基麦芽酚、4-乙基-愈创木酚、苯甲醛、4-乙基苯酚,水杨酸甲酯,乙酸,己醛,苯甲酸乙酯。