光强对砀山酥梨果实发育期Ca2+、Zn2+含量变化的影响

本实验以砀山酥梨为实验材料研究梨果实发育期间C a2+、Zn2+含量的变化规律以及与光强的关系。结果表明:(1)砀山酥梨果实C a2+、Zn2+浓度在盛花后第1周和第7周出现两次高峰,这正是石细胞形成的关键期,说明C a2+、Zn2+浓度大小与石细胞的形成有关;(2)梨果实吸收C a2+、Zn2+主要在幼果期,且表现出高光强>中光强>弱光强>极弱光强。     

Shelf life,physicochemical, microbiological and antioxidant properties of purple cactus pear (Opuntia ficus indica) juice after thermoultrasound treatment

The objective of this study was to evaluate changes in color, betalain content, browning index, viscosity, physical stability, microbiological growth, antioxidant content and antioxidant activity of purple cactus pear juice during storage after thermoultrasonication at 80% amplitude level for 15 and 25 min in comparison with pasteurized juice. Thermoultrasound treatment for 25 min increased color stability and viscosity compared to treatment for 15 min (6.83 and 6.72 MPa, respectively), but this last parameter was significantly lower (p < 0.05) compared to the control and pasteurized juices (22.47 and 26.32 MPa, respectively). Experimental treatment reduced significantly (p < 0.05) sediment solids in juices. Total plate counts decreased from the first day of storage exhibiting values of 1.38 and 1.43 log CFU/mL, for 15 and 25 min treatment, respectively. Compared to the control, both treatments reduced enterobacteria counts (1.54 log CFU/mL), and compared to pasteurized juice decreased pectinmethylesterase activity (3.76 and 3.82 UPE/mL), maintained high values of ascorbic acid (252.05 and 257.18 mg AA/L) and antioxidant activity (by ABTS: 124.8 and 115.6 mg VCEAC/100 mL; and DPPH: 3114.2 and 2757.1 μmol TE/L). During storage thermoultrasonicated juices had a minimum increase in pectinmethylesterase activity (from day 14), and exhibited similar total plate counts to pasteurized juice. An increase of phenolic content was observed after 14 days of storage, particularly for treatment at 80%, 25 min, and an increase in antioxidant activity (ABTS, DPPH) by the end of storage.     

地理标志产品仓桥水晶梨质量安全溯源系统的建立与实现

食品溯源系统是食品安全监管的重要手段之一,其核心功能包括溯源信息的记录、传递和查询.本文中建立了一套以二维码为表现方式的安全溯源系统.该系统以上海仓桥水晶梨为例,以《地理标志产品保护规定》并结合本地化的全球农业良好生产管理规范要求(LocalGAP,All Farm Base,Crops Base,2013)为溯源点信息采集依据,通过生产过程实地调研、溯源流程设计、数据库搭建及溯源系统平台4个部分的研究,建立了能够快速查询产品安全信息的系统,为消费者食品安全溯源提供了一个新的渠道;同时,系统中包含的果园行业数据库,可为监管部门及相关企业推送重要的提升管理效率的数据.     

The disappearance rate and risk assessment of thiacloprid residues in Asian pear using liquid chromatography confirmed with tandem mass spectrometry

This study was undertaken to quantify the residue levels and propose the dissipation kinetics of thiacloprid formulated as suspension concentrate in field‐incurred Asian pears grown under two different open‐field conditions. Samples were extracted with 20% distilled water in acetonitrile; partitioned with brine water and dichloromethane; and purified with a Florisil solid phase extraction cartridge. The analyte was identified with an LC ultraviolet detector, and field‐incurred samples were confirmed using LC–MS/MS. The calibration curve was linear over the range 0.05–5.0 mg/L with a satisfactory coefficient of determination (R ² = 0.9994). The limits of detection and limits of quantification (LOQ) were 0.003 and 0.01 mg/kg, respectively. The recovery rate fortified to blank samples at LOQ, 10× LOQ, and the maximum residue limit (MRL) were between 73.7 and 86.2% with relative standard deviation ≤9.0%. The residual concentrations at both sites were considerably lower than the MRL (0.7 mg/kg) set by the Korean Ministry of Food Drug Safety, with biological half‐lives of 5.0 and 7.4 days, for sites 1 and 2, respectively. From the pre‐harvest residue limit curve, it was predicted that if the residues were <1.13 or 1.40 mg/kg 10 days before harvest, the residue level would be lower than the MRL during harvest. Risk assessment on day 0 showed an acceptable daily intake (%) of 13.0% and 11.0% for sites 1 and site 2, respectively, which indicates that the residual amounts are not hazardous to the Korean population.     

抗褐变与褐变安梨叶片的酶活性比较

为了探寻抗褐变安梨品系燕安3叶片中相关酶活性与果实抗褐变之间的关系,以燕安3和不抗褐变的对照品种燕安1,燕安2的叶片为材料,测定了POD,CAT,PPO,SOD等酶活性。结果表明:燕安3叶片中POD,CAT活性分别为(48.36±3.27)U/(g.min)和(122.65±8.34)U/(g.min),均显著高于两个对照品种;且3个安梨品种(系)叶片中POD,CAT,PPO活性由大到小的排序均为:燕安3,燕安1,燕安2;而安梨叶片中SOD活性则与果实褐变度不相关。     

梨瘿螨的为害对梨叶片几种生理生化指标的影响

梨树叶片被梨瘿螨为害后，一些生理生化指标发生了变化，经光谱技术、化学方法和电物理方法测定，与健康叶片相比受害部位的叶绿素含量下降31．85％，可溶性糖含量下降24．61％，可溶性蛋白质含量上升34．14％，游离氨基酸含量上升29．95％，游离脯氨酸含量上升84．08％，过氧化氢酶活性增加29．82％，膜透性增加86．74％，中度受害叶的螨瘿部位与病健部位相比叶绿素含量下降26．86％，可溶性糖含量下降22．79％，可溶性蛋白质含量上升30．26％，游离氨基酸含量上升22．81％，游离脯氨酸含量上升16．01％，膜透性增加45．54％，过氧化氢酶活性增加15．87％，说明叶绿素、可溶性糖含量的下降和可溶性蛋白质、游离氨基酸、游离脯氨酸的上升以及过氧化氢酶活性和组织细胞膜透性的增强都主要集中在受害部位。     

安梨发酵酒的酿造工艺研究

安梨发酵液的提取中，加入０．２％的果胶酶制剂，比对照提高出汁率２０％左右。在安梨酒的酿造中，以纯汁发酵的方式，采用１５～２０℃的低温发酵处理，较好地保持了安梨酒的独特果香，酒体纯正柔和、绵软爽口，突出了安梨酒的风格。成品避光贮存陈酿，减少了酒中维生素Ｃ的氧化损失。     

套袋对黄花梨果实品质的影响

以6年生黄花梨树为试验材料,研究了套袋对其果实品质的影响.试验结果表明:与套白色单层塑料袋和对照相比,在5月中旬黄花梨果实套双层纸袋后果面光洁度显著提高,病虫果发生率降低,着色趋于一致,果点变小、数量减少,明显改善了果实的商品外观,增加了果实硬度和维生素C的含量.尽管果实大小和可溶性固形物略有降低,但不影响果实内在品质.     

阳山洞冠梨的初步研究

本文介绍了洞冠梨的栽培历史及进行初步性状描述和评价情况，总结了生产中存在的关键性问题并提出研究解决方向和途径。     

常德市园林绿地系统规划设计与研究

在分析常德市得天独厚的自然生态环境资源的基础上 ,通过对城市园林绿地系统的总体规划设计与研究 ,探索现代生态园林城市特色的塑造与可持续发展 .