果蔬产品采后呼吸作用与贮运保鲜研究

呼吸作用是果蔬产品采后最为基本的生理过程,降低采后呼吸作用,维持果蔬产品正常而缓慢的生命活动,是果蔬采后生理及贮藏技术研究的中心问题.该文从呼吸作用入手,阐述了呼吸的基本概念,影响果蔬呼吸作用的因素及生理意义,可为呼吸作用的课堂教学提供参考.     

基因工程在食品工业中的应用进展

简要介绍了基因工程技术，综述了基因工程技术在改善食品品质和加工特性、增强果蔬食品的贮藏保鲜性能以及在发酵工业食品和保健、特殊食品方面的研究应用现状。讨论了转基因食品的安全性及检测技术。     

NO延缓果蔬成熟衰老与抗病机理研究进展

一氧化氮是具有生物活性和信号转导作用的易扩散小分子气体,果蔬细胞通过一氧化氮合酶(NOS)、硝酸还原酶或非生化反应途径产生NO。内源NO可通过抑制乙烯的生物合成和调控环化核苷酸在植物组织中的水平来延缓植物组织的成熟和衰老,延长果蔬贮藏货架期;NO还可诱导采后果蔬产生抗病防卫反应,提高果蔬的抗病胁迫能力。着重概述NO在果蔬采后延缓成熟衰老、诱导抗病等方面的作用及其机理研究进展。     

一些亚热带果蔬的适宜贮藏条件

美国农业部新近颁发了一份关于水果蔬菜的适宜贮藏条件方面的研究资料(USDAHandbook No.＃66),具有一定的参考价值,现选译亚热带果蔬部分报道如下.     

热带果蔬采后冷害研究进展

果蔬采后冷害机制及其防控是当前采后研究领域中倍受关注的科技问题。果蔬冷害发生是由内在因子和外部环境因素共同作用的结果。近年来,随着现代分子生物学技术的应用,并借鉴模式植物拟南芥的研究成果,果蔬采后冷害发生调控机理及防控技术研究取得一系列进展。本文综述了热带果蔬采后冷害发生的生理与分子机制和冷害防控技术的最新研究成果,关注能量代谢调控果蔬采后冷害作用,重点介绍了生物技术在防控果蔬冷害上的应用,并对今后研究方向作了展望。     

果蔬中食源性致病微生物的研究进展

全球食源性疾病的发生呈增长态势,由果蔬中食源性致病微生物引发的疾病也在逐年增加。因此,各国对于果蔬中食源性致病微生物的检测也越来越重视。目前,食源性致病微生物的快速检测和相关的防控技术成为研究的热点,本文综述果蔬中常见大肠杆菌、李斯特菌和沙门氏菌的种类、特性、病症、检测方法及防控技术,为保障食品安全提供参考。     

采后褪黑素处理对余甘子果实品质和耐贮性的影响

余甘子（Phyllanthus emblica L.）是联合国卫生组织指定的全世界推广种植的3种保健植物之一,在中国也被列为药食两用的水果,具有营养丰富,保健价值突出的特点。然而采后余甘子果实易发生失水皱缩、腐烂变质等问题,极大地影响了其商品价值。褪黑素（melatonin）是一种小分子吲哚胺类物质,在动植物体内广泛存在,其在植物中可有效清除自由基,在植物的抗逆抗病中也具有重要的调控作用。采用适宜浓度的褪黑素处理果蔬可以起到较好的保鲜作用,有效延缓果蔬腐败变质,提高采后耐贮性。为提高余甘子果实采收后的耐贮性,以‘蓝丰’余甘子果实为试材,探究采后褪黑素处理对于常温下贮藏的余甘子果实品质和耐贮性的影响。将挑选出的无机械损伤及病虫害,大小和色泽相近的余甘子果实,随机平均分为2组,处理组余甘子用0.3 mmol/L褪黑素溶液浸泡处理20 min,空白对照组则用去离子水浸泡20 min,取出晾干1 h后用聚乙烯薄膜袋包装,而后置于温度为(25±1)℃、在相对湿度85%~90%的恒温箱中贮藏,每3 d取样测定果实的商品率、感病指数、呼吸强度等品质和耐贮性相关指标。试验结果表明,采后褪黑素处理使余甘子果实在贮藏末期的商品率提高22%,显著降低了余甘子果实的感病指数、呼吸速率和失重率;且经褪黑素处理的余甘子果实可溶性固形物、可滴定酸度和维生素C的含量均高于对照组,余甘子表皮颜色和果肉质地的劣化也比对照缓慢。褪黑素处理有利于延缓采后余甘子病害的发生和提高果实品质及耐贮性。本研究为褪黑素在余甘子果实采后贮藏保鲜应用提供理论依据,丰富了褪黑素应用于果蔬保鲜的理论基础。     

大葱种子加工贮藏技术探讨

介绍了大葱种子清选、合理干燥、正确包装的加工贮藏技术要点,重点阐述了大葱超干贮藏、超低温贮藏技术。     

商品马铃薯的贮藏技术

马铃薯是世界各国的主贮蔬菜之一,其鲜薯含水分达80%左右,比一般作物种子难以贮藏。马铃薯的贮藏受到条件以及管理技术的局限,贮藏效果也不尽相同。本文简单介绍了马铃薯对贮藏条件的要求、贮藏方法和贮藏期间应注意的问题,以期为获得更好的贮藏效果提供参考。     

杂交水稻种子贮藏过程活力保持研究进展

杂交水稻种子贮藏过程中活力的保持问题已成为制约杂交稻种子产业快速发展的关键问题。研究种子活力的机理,探索水稻种子贮藏过程活力调控与保持技术是降低杂交稻种子生产与贮藏风险、保证粮食安全的最有效途径。综述了杂交水稻种子储藏过程中活力保持研究的意义和现状,并就杂交水稻种子贮藏中保持活力的技术进行了探讨与展望。     

采后果蔬冷害与能量关系研究进展

就冷害与果蔬的线粒体、能荷水平及代谢过程三者之间的关系,结合目前国内外相关的研究进行综述,从果蔬冷害与能量的角度,探讨果蔬冷害与抗冷性机制。     

Chemical composition of indigenous wild herbs,spices, fruits,nuts and leafy vegetables used as food

Thirty wild fruits, nuts, herbs, spices and leafy vegetables were characterized and their chemical composition determined. Some of them were not only used for food, but for medicine in minor aliments by the natives. Results of the proximate analysis showed that on dry weight basis, the crude protein content ranged from 4.6 to 22.1 percent for spices and herbs, 3.2 to 43.1 percent for fruits and nuts, and 15.9 to 35.7 percent for leafy vegetables. The fat (ether extract) ranged from 7.5 to 36.0 percent for spices and herbs, 1.8 to 72.6 percent for fruits and nuts and 10.6 to 22.6 percent for leafy vegetables. Total carbohydrate content ranged from 34.6 to 71.9 percent for spices and herbs, 11.3 to 76.1 percent for fruits and nuts, and 24.6 to 51.4 percent for leafy vegetables. The wild fruits, nuts and leafy vegetables are high in ascorbic acid (Vitamin C.) Ascorbic acid content ranged from 18 mg/100 g dry sample to 113 mg/100 g sample for fruits and nuts, and 23 mg/100 g to 232 mg/100 g sample for leafy vegetables. The levels for peroxide value and free fatty acids (as percent oleic acid) of the spices are generally low indicating good storage stability of these plant materials. The flavour imparting essential oils (as percent oleoresin) content of the spices/herbs were fairly high and ranged from 0.1 to 5.2 percent.     

Influence on growth conditions on the value of crisphead lettuce

Storage of crisphead lettuce was carried out at 1°C in an ordinary cold storage room and in an ice bank cooling system. The plants were grown at three plantings at 50, 100, 150 and 200 kg total nitrogen supply per hectare and harvested at two or three different plant ages. The cultivars used were ‘Marius’ and ‘Saladin’. The aim of the experiment was to prolong the storage and to reduce the losses. After 14 days of storage the greatest total weight losses were found at the mid-season planting whereas the least total weight loss was found at the late planting. Ice bank cooling at all plantings reduced the total weight loss in comparison to the cold storage. The effect of nitrogen and cultivar was low. The total weight loss defined as loss due to transpiration and trimming was neither related to the head weight nor the surface area of the heads. A reduced loss with increasing plant age was not a question of increased transpiration due to surface to volume ratio changes, but may be related to other factors. A lower average total weight loss was found in the ice bank cooling system compared to the cold storage. The explanation of this might be the existence of a high relative humidity in the ice bank storage. To reduce the total weight loss harvest must take place at the right plant age. No definite growth stage was defined here, but the plants must have reached marketable quality as the young plants are more susceptible to weight loss during storage. It seems likely that some unknown internal factors in the plant were involved in reduction of the total weight loss.     

风冷冰箱和直冷冰吧贮藏龙井绿茶的效果比较

为探究采用风冷冰箱和直冷冰吧贮藏对龙井绿茶品质的影响,把茶叶分别存储于风冷冰箱的冷藏室和冷冻室、直冷冰吧的冷藏室和冷冻室等4种不同的贮藏环境中贮藏90、180、270、360βd时分别取样,通过生化成分含量测定及感官审评等分析比较不同贮藏条件对绿茶的存储效果。结果表明,整个贮藏期内,冷冻室对生化成分的存储效果优于冷藏室,其中风冷冰箱冷冻室能有效地保持茶叶低含水率,贮藏180βd时其含水率显著低于直冷冰吧（P<0.05）,直冷冰吧冷冻室则对叶绿素、维生素C、咖啡碱等含量保持效果较好,贮藏180βd时其维生素C和咖啡碱含量显著高于风冷冰箱（P<0.05）;在0~180βd的贮藏期内,氨基酸、茶多酚、儿茶素均在风冷冰箱的冷冻室保留率高（均约为95%）,贮藏后期则在直冷冰吧的冷冻室保留率高,且贮藏结束时均与风冷冰箱差异显著（P<0.05）。风冷冰箱有利于绿茶滋味和香气的保持,直冷冰吧有利于绿茶外形的保持,即不同贮藏条件对茶叶的感官分属性的影响不同。正交偏最小二乘判别分析（OPLS-DA）结果表明,汤色、滋味、香气、咖啡碱和维生素C等品质指标在不同的贮藏方式间差异较大。结合两设备的特点可知,茶叶相对短期存储时可选择风冷冰箱,长期存储时则直冷冰吧更优。     

海南入境台湾果蔬危险性有害生物普查及其安全性评估

适应海南入境台湾果蔬产业健康、快速、可持续发展的需要，系统开展了海南入境台湾果蔬危险性有害生物普查，并采用PRA评估模型对17种外来入侵危险性有害生物进行了风险评估。2009～2010年考察发现，海南入境台湾果蔬以芒果、西瓜、哈密瓜、辣椒、番茄、莲雾、番木瓜和番石榴为主，主要分布在文昌、琼海、三亚、乐东、东方、昌江、澄迈、海口等农场和瓜菜生产基地，并且各瓜菜品种种植面积因市场价格影响年份间波动较大；调查共查获海南入境台湾果蔬危险性有害生物68种，包括害虫32种，病原微生物16种，杂草20种，其中外来入侵危险性有害生物17种；大面积严重发生与危害危险性有害生物25种；桔小实蝇、螺旋粉虱、烟粉虱、西瓜细菌性果斑病在海南均属于高度危险有害生物。上述结果为进一步开展海南入境台湾果蔬危险性有害生物监测预警与防控提供了前期工作基础。     

Retention of quality characteristics of dehydrated green leaves during storage

Green leafy vegetables are the most underexploited class of vegetablesdespite high nutritional value. Reports on nutritional composition andstorage of some of the fresh leaves are available but the storage behaviorof dehydrated leaves apparently has not been studied. Therefore, in thepresent study, two green leafy vegetables, savoy beets (Beta vulgarisvar. bengalensis) and fenugreek (Trigonella foenumgraecum) were dehydrated in a low temperature drier and stored for9 months under ambient and cold stored conditions after packaging insingle or double layers of high density polyethylene film (200 gauge). Thequality was determined on the basis of retention of -carotene,ascorbic acid and chlorophyll, and the extent of browning during storage.Retention of these quality characteristics depended on the crop and storageconditions. Double packed and cold stored samples of fenugreek retained67% -carotene, whereas savoy beet leaves retained only 57% ofthe initial -carotene under similar conditions. Similarly, higherretention of ascorbic acid and chlorophyll, and lower browning wasobserved in double packed, cold stored samples. Results indicated theefficacy of double packed and cold stored samples over other combinations.     

Effect of a natural high fibre diet on blood lipids and intestinal transit time in man

In two experiments with young healthy volunteers the effects of a high in take of dietary fibre on blood lipids and intestinal transit time were investigated. In the first experiment the effects were studied of a high-fibre diet, in which half of the dietary fibre was provided by vegetables and fruits and the rest came from bread and other cereal products. In the second trial the effects of dietary fibre derived from vegetables and fruits were compared with those of isolated citrus pectin and wheat bran. It is concluded that—at least in short-term controlled experiments—fibre-rich food-stuffs have only a small (vegetables and fruits) or no (bran) favourable effect on the level of serum cholesterol. However, in uncontrolled circumstances, a ‘natural’ high fibre diet may through its low fat and cholesterol content indirectly reduce the concentration of serum cholesterol. A high-fibre diet with vegetables and fruits as well as a diet with bran shorten the intestinal transit time and enhance faeces production.