葡萄的贮藏保鲜

葡萄果实属于浆果类，柔软多汁，含糖量较高。由于葡萄皮薄、汁液多，果柄部分组织结构疏松，采后容易干柄脱粒和腐烂。所以，搞好葡萄的保鲜对促进农村经济的发展，为消费者保障均衡的季节供应都有好处。根据葡萄果实的特点，可以采用以下几种保鲜方法： 一、采前处理 果园于采摘前一个星期停止浇水，采收当天喷５００ｐｐｍ的扑海因杀菌剂，以控制采后贮藏病害；或喷洒５０ｐｐｍ奈乙酸以防止葡萄落粒。最好选择晴天将药液兑好后，直接喷洒于果穗上，待药液干后即可采摘。 二、采收 葡萄果实采后没有呼吸高峰，也没有后熟作用，因此葡萄…     

羧甲基壳聚糖的制备及其在保鲜中的应用

研究了在碱性条件,无溶剂体系下壳聚糖羧甲基化制备工艺,通过IR对反应前后壳聚糖结构进行了表征。最佳反应条件：2g壳聚糖,在NaOH加入量为5g、碱化时间为6h、氯乙酸用量为6g、3％KI、反应时间为8h、反应温度60℃,产品取代度为1．27。同时研究了羧甲基壳聚糖对辣椒、猪肉涂膜保鲜实验,结果显示对辣椒、猪肉具有较好的涂膜保鲜作用。     

鲜食葡萄的采后生理及贮运保鲜

论述了葡萄的成熟及采后生理生化特性,采后的各种主要病害和次要病害以及鲜食葡萄的采后贮运方法和国际通用的葡萄保鲜方法──ＳＯ_２熏蒸法的原理和研究进展。     

壳聚糖与植物精油复配在食品保鲜中的应用

综述了壳聚糖与精油复配使用在新鲜水果、水产品和蔬菜中应用的研究进展,并对壳聚糖 植物精油复合保鲜膜存在的问题和研究趋势进行了讨论。     

采前二氧化氯处理对‘海沃德’猕猴桃的防腐保鲜效果

研究了采前二氧化氯（ClO2）处理对采后‘海沃德’猕猴桃果实在冷藏条件下的防腐保鲜效果。分别用浓度（有效成分）为0、20、40、60、80mg·L-1的ClO2溶液,在采收前对果实进行喷布处理,在采收后冷藏过程中定期测定相关生理指标,并在贮藏末期（120d）观察统计其腐烂指数。结果表明,浓度60mg·L-1的ClO2采前处理可有效清除猕猴桃果实表面菌落,并能显著延缓冷藏期间果实硬度的下降、抑制可溶性固型物的上升、降低猕猴桃呼吸速率、乙烯释放速率、失重和腐烂指数,提高过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性。通过比较,确定采前ClO2处理的适宜浓度为60mg·L-1。该浓度的ClO2处理对‘海沃德’猕猴桃具有明显的防腐保鲜效果,可有效延长贮藏期。     

基因工程在园艺作物采用保鲜中的应用

通过基因工程技术培育出长久保存的园艺作物品种以延长其采后保鲜期,本文对应用这一技术的策略,研究进展及商业化前景分别给予介绍。     

钙肥和硅肥对葡萄留树保鲜效果的影响

以白罗莎里奥葡萄为试材,通过分析钙、硅肥处理对葡萄果实品质、烂果率、生理指标及休眠期冬芽发育的影响,研究了钙、硅肥在葡萄留树保鲜中的应用效果。结果表明:100 mg/L硅酸钠和1.5%的硝酸钙处理葡萄留树保鲜效果最佳,可减缓葡萄果实成熟后果实品质变化,降低葡萄果实中丙二醛的含量和多酚氧化酶活性,又能促进冬芽的发育,从而可以有效抵充留树保鲜对树体营养的消耗,不会影响次年生产。     

蝇蛆壳聚糖保鲜剂对几种蔬菜的保鲜作用研究

研究了蝇蛆壳聚糖水溶剂对番茄、青椒、茄子的保鲜作用,并试图找出保鲜效果较好的蔬菜.贮藏期间,定期测试其生理生化指标:失水率、腐烂率、呼吸强度、维生素C(Vc)含量.结果表明:用蝇蛆壳聚糖保鲜剂处理过的三种蔬菜各生理生化指标都比空白对照的效果好.说明蝇蛆壳聚糖能减少蔬菜的水分损耗,限制其呼吸作用,减少营养损失.三种蔬菜中,番茄在12天内、青椒在4-6天内的保鲜效果最好.     

茶多酚与壳聚糖复配溶液对香椿芽保鲜效果的研究

为研究茶多酚与壳聚糖复配溶液对香椿芽的保鲜效果,该研究以多年生香椿树嫩芽为材料,采用不同浓度茶多酚(TP)与壳聚糖复配溶液处理香椿芽,(4±1)℃条件下贮藏,测定贮藏期间香椿芽感官变化和生理生化指标以及腐烂率的变化。结果表明:一定浓度的茶多酚与壳聚糖复配溶液可维持香椿芽的感官品质、降低生理衰老程度并减少腐烂率。其中,0.3%茶多酚-0.5%壳聚糖复配液对香椿芽保鲜效果最显著。0.3%茶多酚-0.5%壳聚糖复配液处理的香椿芽在贮藏12 d时失重率仅为1.52%、维生素C保持率为63.08%、叶绿素损失率为20.67%,同时对降低香椿芽的腐烂率和脱叶率有明显效果,贮藏21 d香椿芽的完好率接近84%、脱叶率为8%。1%茶多酚会加剧香椿芽的腐败脱叶,掩盖了香椿芽原有的香味,并导致褐变现象。因此,0.3%茶多酚-0.5%壳聚糖复配液在香椿芽保鲜方面具有较好的应用价值。     

壳聚糖涂膜对辣椒采后生理的影响

以不同浓度的壳聚糖溶液作为辣椒的涂膜保鲜荆,研究其对辣椒采后生理的影响。结果表明,壳聚糖涂膜可显著降低辣椒的失水率、腐烂指数、丙二醛含量,抑制叶绿素和Vc以及超氧化物歧化酶活性的降低。     

Mechanisms of killing of Bacillus subtilis spores by hypochlorite and chlorine dioxide

AIMS: To determine the mechanisms of Bacillus subtilis spore killing by hypochlorite and chlorine dioxide, and its resistance against them. METHODS AND RESULTS: Spores of B. subtilis treated with hypochlorite or chlorine dioxide did not accumulate damage to their DNA, as spores with or without the two major DNA protective alpha/beta-type small, acid soluble spore proteins exhibited similar sensitivity to these chemicals; these agents also did not cause spore mutagenesis and their efficacy in spore killing was not increased by the absence of a major DNA repair pathway. Spore killing by these two chemicals was greatly increased if spores were first chemically decoated or if spores carried a mutation in a gene encoding a protein essential for assembly of many spore coat proteins. Spores prepared at a higher temperature were also much more resistant to these agents. Neither hypochlorite nor chlorine dioxide treatment caused release of the spore core's large depot of dipicolinic acid (DPA), but hypochlorite- and chlorine dioxide-treated spores much more readily released DPA upon a subsequent normally sub-lethal heat treatment than did untreated spores. Hypochlorite-killed spores could not initiate the germination process with either nutrients or a 1 : 1 chelate of Ca2+-DPA, and these spores could not be recovered by lysozyme treatment. Chlorine dioxide-treated spores also did not germinate with Ca2+-DPA and could not be recovered by lysozyme treatment, but did germinate with nutrients. However, while germinated chlorine dioxide-killed spores released DPA and degraded their peptidoglycan cortex, they did not initiate metabolism and many of these germinated spores were dead as determined by a viability stain that discriminates live cells from dead ones on the basis of their permeability properties. CONCLUSIONS: Hypochlorite and chlorine dioxide do not kill B. subtilis spores by DNA damage, and a major factor in spore resistance to these agents appears to be the spore coat. Spore killing by hypochlorite appears to render spores defective in germination, possibly because of severe damage to the spore's inner membrane. While chlorine dioxide-killed spores can undergo the initial steps in spore germination, these germinated spores can go no further in this process probably because of some type of membrane damage. SIGNIFICANCE AND IMPACT OF THE STUDY: These results provide information on the mechanisms of the killing of bacterial spores by hypochlorite and chlorine dioxide.     

葡萄、鲜枣采后贮期脱落酸（ABA）变化与呼吸非跃变性研究

以葡萄,鲜枣为材料研究了果实采且贮期ABA的变化与呼吸非跃变性,结果表明;葡萄,鲜枣均为呼吸非跃变型果实,贮期ABA的变化呈抛物经形,有明显的高峰出现,对于呼吸非跃变型果实,ABA尽管不导致呼吸高峰的出现,但贮期ABA峰值高的果实,呼吸强度高,三碘苯果酸处理后低温贮藏葡萄,鲜枣,抑制ABA形成作用明显,具有良好的保鲜效果。     

壳聚糖复合物的抑菌性研究

自制了壳聚糖系列复合物(CTS-X):黄原酸化壳聚糖(CTS-CS2)、巯基化壳聚糖(CTS-SH)、壳寡聚糖(O-CTS)、不同溶剂化的壳聚糖(CTS)及这些物质的系列金属离子(Ca、Zn、Fe、Mn、Cu、Ni、Co、Ag)配合物。分别用圆滤纸法和杯碟法对细菌和真菌:金黄葡萄球菌、枯草杆菌、大肠杆菌及黑曲霉和冻土毛霉等,进行了抑菌性研究。并讨论了最低抑菌浓度,作了抑菌曲线。经系统筛选得到对枯草杆菌有特效抑菌性的黄原酸化壳聚糖锌(CTS-CS2-Zn),对金黄葡萄球菌有特效抑菌性的黄原酸化壳聚糖银(CTS-CS2-Ag)。并用具有一定抑菌性和一定还原性的CTS-X作为水果保鲜剂对草莓、荔枝、樱桃等作了保鲜研究,收到良好效果。为CTS-X的广泛应用提供了实验依据。     

葡萄多酚物质提取方法的研究

对葡萄多酚物质提取分离影响因子进行正交试验,以确定各提取工艺路线的最佳条件,并对各种方法进行了比较。在实验室条件下,有机溶剂提取是进行葡萄多酚物质相关研究的适宜方法,其最佳因子组合为C3D2A2B1,即在70C,50％乙醇浓度,5倍体积比提取60min。同时对提取、萃取的次数和提取时材料的干燥程度进行了研究。     

Controlling grape must fermentation in early winemaking phases: the role of electrochemical treatment

AIMS: To contribute to an understanding of the phenomena related to the effect of low electric current (LEC) in grape must fermentation during laboratory and pilot plant scale winemaking, with selected co-culture yeasts (Saccharomyces cerevisiae strain 404 and Hanseniaspora guilliermodii strain 465). METHODS AND RESULTS: LEC (10, 30, 50 and 100 mA) was applied to fresh grape must as an alternative method to the usual addition of SO2. Parameters such as polarity, treatment duration (24-96 h) and type of inoculum yeast were varied one at a time. LEC decreased the survival time and increased the death rate of H. guilliermondii strain 465 in co-cultures, whereas it did not affect the growth and survival of S. cerevisiae strain 40. A final comparison was made of the main physico-chemical parameters on wine obtained after the different tests. CONCLUSIONS: The results have demonstrated that the low voltage treatment using a pair of graphite electrodes had a positive effect on grape juice fermentation (yeast microflora) during the early stages of winemaking, even with the potential of being an alternative method to the usual addition of SO2. SIGNIFICANCE AND IMPACT OF THE STUDY: These results could be of significant importance in developing new winemaking technologies for an innovative yeast fermentation control process for 'biological wine'.     

HPLC测定葡萄中活性物质—白藜芦醇的含量

采用ＨＰＬＣ法测定葡萄中白藜芦醇的含量。用以Ｃ１８ＯＤＳ为流动２相,检测波长为３０７ｎｍ。在此条件下,样品溶液的进样量在０．２８６－２８．６ｍｇ／Ｌ时,白藜芦醇５的含量与峰面积呈良好的线性关系,回收率为１２３．８５％。     

用反义技术解决番茄保鲜的研究进展

目前发现20多种与果实发育有关的酶和蛋白,其中14种mRNA在果实成熟过程中增加,8种受乙烯诱导,相关的基因已被克隆、测序并在染色体上定位．利用反义技术抑制这些酶和蛋白的表达,一方面可研究它们在果实成熟过程中的作用,另一方面从分子水平上解决了番茄保鲜问题．已将7种反义基因导入番茄,反义果实在离体条件下可保鲜90～120d．     

葡萄胚挽救苗移栽技术的研究

以欧洲葡萄无核品种与中国野生葡萄杂交的胚挽救苗为试材,系统地研究了移栽时期、胚挽救苗质量、移栽方法及移栽基质对葡萄胚挽救苗移栽成活率的影响。结果表明,春季选择壮苗,先无菌条件下移栽到珍珠岩中进行培养室炼苗,再经温室炼苗,移栽成活率最高,可达98．8％。初步探索出一套简单易行、实用高效的葡萄胚挽救苗优化配套移栽技术。