膜孔灌条件下不同氮肥施用后的转化特性研究

通过室内入渗试验,研究了膜孔灌条件下不同氮肥的转化特性。结果表明,施入铵态氮肥后土壤铵态氮含量在膜孔中心垂向表层0～5．5 cm内变化,再分布15 d土壤铵态氮损失了68％,再分布20 d铵态氮基本完全转化;随再分布时间的延长,硝态氮的含量在土壤表层10 cm范围内逐渐增加,在10 cm以下,硝态氮的含量7 d前先增大再减小,7 d后一直增大。施入硝态氮肥后,硝态氮含量7 d内变化很小,7～10 d内明显减少,10 d以后减少缓慢。施入尿素后,土壤中铵态氮在5 d后达到峰值,20 d后下降至土壤的本底值;而土壤硝态氮一直平稳升高,于施肥20 d后达到最大值;土壤铵态氮含量和硝态氮含量均沿着远离膜孔中心的方向逐渐减小。     

植物精油在果蔬保鲜中的应用

植物精油多提取于香辛料及中草药植物的花、叶、茎、根或果实,具有显著的抑菌效果,且安全无毒,是一种理想的天然果蔬保鲜剂。通过对植物精油的抑菌活性、果蔬防腐保鲜的作用及其机理等方面进行综述及分析可知,植物精油的开发利用必将迎来更加广阔的前景。     

不同商品化处理及保鲜膜包装对芦蒿冷藏效果的研究

芦蒿是以嫩茎供食的蔬菜。本试验以青杆型芦蒿为材料,研究带叶、去叶、鲜切三种商品化处理方式及0.02、0.05 mm厚度的PE膜、微孔膜三种保鲜膜包装对其(2±0.5)℃冷藏保鲜效果的影响。结果表明,去叶处理在减少VC等营养物质损耗、延缓采后纤维化及维持感官品质等方面优于带叶和鲜切处理;同时芦蒿具有较好的CO2耐受性,用厚度0.05 mm PE膜包装的保鲜效果优于另外两种保鲜膜包装。     

Establishment of reliable methods of in vitro pollen germination and pollen preservation of Brassica rapa (syn. B. campestris)

A simple and reliable method for evaluating the viability of Brassica pollen was established in which the in vitro germination rate of pollen was adopted as the index of the viability of pollen grains. Pollen grains were preincubated in an atmosphere in which the relative humidity (RH) was fixed to 52% or 66% at 20 °C for 5 hours. They were cultured for 16 hours at 25 °C in a liquid Kwack's medium (1964) supplemented with 20% sucrose, and the pH was adjusted to 8.0. They were then observed under a microscope and the number of germinating and unchanged pollen grains were counted. The germination rate of pollen was improved and stabilized by preincubation and the use of a high pH medium. More than 90% of the freshly harvested pollen grains of Brassica rapa (syn. B. campestris) germinated constantly in these conditions Undehisced anthers were collected from flowers at anthesis and dehydrated by incubation at 20 °C for 16–24 hours in an atmosphere where the RH was fixed to 15% or 32%. They were put into a plastic vial and preserved in a freezer at -20 °C. The germination percentage of the preserved pollen was scored at intervals during preservation. The germination rate of the pollen grains preserved at -20°C for 1 year was higher than 50% and the pollen proved to be efficient for seed set. Most of the seeds germinated normally. This revised version was published online in August 2006 with corrections to the Cover Date.     

枇杷采后生理变化与贮藏保鲜技术

阐述枇杷采后主要生理变化,并对采后贮藏保鲜技术处理作逐一介绍.     

国内外果蔬生物保鲜方法的研究现状与展望

概述果蔬生物保鲜方法的种类、原理和技术,同时对现阶段生物保鲜技术在果蔬贮藏保鲜中的应用进行综述,最后对生物保鲜技术存在的问题和未来研究方向进行展望.     

国内外果蔬鲜切加工及保鲜技术研究现状

随着工作节奏的加快,方便快捷食品需求的增强,鲜切加工产品越来越受到关注。阐述了鲜切产品的加工过程、原料来源及选择,清洗、去皮、切分、护色、包装和贮藏等各项技术,论述和比较了鲜切产品的保鲜技术包括冷藏保鲜、保鲜剂保鲜、MAP保鲜及冷杀菌保鲜等,分析了加工过程中需要注意的问题,最后对鲜切加工技术的发展提出了展望。     

壳聚糖-山梨酸复合涂膜对宣城圆枣保鲜效果的影响

针对鲜食红枣成熟后贮藏期短,商品性会随贮藏期延长而降低等问题,以宣城圆枣为试材,采用5个浓度(0.1%、0.25%、0.5%、1.0%、1.5%)壳聚糖与浓度为0.1%的山梨酸混合,配制成复合保鲜液,对其进行涂膜保鲜处理。结果表明:在4℃条件下,壳聚糖-山梨酸复合涂膜处理在一定程度上能延缓宣城圆枣果实失重率与腐烂率上升的速度,同时抑制硬度及VC含量的下降,从而延缓果实的成熟衰老进程,提高贮藏品质,延长货架期。通过对各项果实品质指标数据的综合分析得出,复合涂膜溶液的最佳使用浓度为0.25%壳聚糖+0.1%山梨酸。     

温度处理在柑橘果实采后保鲜中的应用研究进展

柑橘采后贮藏过程中存在营养物质易流失、果实易腐烂、易受病原菌侵染等问题,从而导致极大的采后损失。温度是影响柑橘采后贮藏品质的主要因素之一,合适的温度处理不仅能够使果实在贮藏过程中保持营养价值和风味品质,还能给予果实良好的外观颜色,提高果实的抗病能力。综述了不同温度处理方式对柑橘果实采后生理生化和抗病能力的影响,以期为柑橘采后绿色贮藏技术的研究提供理论参考。     

几种可食膜在杭晚蜜柚柚瓣保鲜中的应用研究

采用3种可食性复合涂膜剂对杭晚蜜柚柚瓣进行涂膜保鲜,同时以不做任何处理的柚瓣为对照,研究常温货架期间蜜柚柚瓣的失重率、可溶性固形物含量、有机酸含量、VC含量、乙醇含量、粒化指数、硬度、菌落总数等指标的变化。结果表明：与对照组相比,涂膜能减少货架期间蜜柚柚瓣的水分损失,抑制VC含量的下降,保持较高的可溶性固形物和有机酸含量,延缓粒化发生,延长货架期。其中,以葡甘聚糖复合膜的保鲜效果较好。