Causes of Decay of Fresh-cut Celery

A decay of fresh-cut celery (Apium graveolens) segments stored at < 5°C in sealed film bags began with a water soaking of the cut surfaces. Slimy moisture accumulated inside the bags. The segments water soaked completely, softened, discolored and sometimes disintegrated. Total aerobic bacterial populations isolated from decayed segments ranged from log₁₀ 7.0–7.7 CFU/g tissue weight. The predominant bacteria, identified by fatty acid analysis as Pseudomonas fluorescens and P. marginalis, caused water soaking, soft rot, and discoloration in freshly inoculated celery tissues stored at 5 or 25°C. Leuconostoc mesenteroides was also isolated and may have been responsible for slime production.     

30%苄氨基嘌呤悬浮剂对芹菜生长和品质的影响

田间条件下研究了不同浓度苄氨基嘌呤悬浮剂对芹菜生长和品质的影响。结果表明,剂量浓度在60~120 mg/kg范围内均可提高芹菜的株高和产量,120 mg/kg剂量浓度处理对亩产量和株高的提高幅度达到了显著水平(P<0.05);药剂对芹菜安全性和品质分析结果表明,试验药剂30%苄氨基嘌呤悬浮剂各剂量浓度对芹菜均没有明显药害,对芹菜的干物质重量、维生素(Vc)和可溶性固形物含量均无显著影响。     

超临界CO_2萃取芹菜籽油研究

用超临界ＣＯ２萃取技术对广东白芹菜籽进行了萃取研究。结果表明，萃取压力低于１５ＭＰａ时，较重的油树脂等成分难以被萃取出来；萃取温度为３０８Ｋ时对萃取最有利；解析温度对萃取效率影响较小；ＣＯ２流量对萃取效率的影响比床层高度引起的扩散阻力的影响大得多。超临界ＣＯ２萃取所得芹菜籽油品质优越，且其中的药用有效成分（３－正丁基－４，５－二氢苯并呋喃酮）含量比水汽法所得芹菜籽油的高五倍多。     

Effects of light exposure on chlorophyll,sugars and vitamin C content of fresh‐cut celery (Apium graveolens var. dulce) petioles

Effects of light exposure (24 μmol m^?2 s^?1) on fresh‐cut celery nutritional quality were evaluated during 8‐day storage at 7 °C using darkness as control. Light exposure preserved 47% chlorophyll a and 48% chlorophyll b contents more than darkness at the end of storage. Sucrose, reducing sugar and glucose contents in light‐stored petioles were 17%, 25% and 67% higher than those in dark‐stored petioles after 8‐day storage, respectively, thus resulting in higher total soluble solids content in light condition. Moreover, l ‐ascorbic acid content increased at 2‐day storage in light condition and was 46% more than in darkness at the end of storage. The fresh weight loss significantly increased in all petioles, and this increase was markedly accelerated by light exposure with a maximum of 1.43% at the end of storage. Dry matter content was induced more by light exposure than by darkness at 2‐day storage.     

基于食品安全指数法和危害物风险系数法评估海南芹菜的农药残留风险

目的 调查海南省市售芹菜的农药残留情况,评估其农药残留风险。方法 从市场上采集115份芹菜样品,采用超高效液相色谱-四极杆串联飞行时间质谱法和气相色谱-三重四极杆串联质谱法对359种农药残留进行筛查,并采用食品安全指数法和危害物风险系数法对检出的农药残留进行风险评估。结果 在所有筛查的样品中有83份检出农药残留,检出率为72.2%,超标率为3.5%。检出农药39种,其中以杀菌剂和杀虫剂为主,检出率最高的杀虫剂为灭蝇胺,杀菌剂为苯醚甲环唑。所有检出的农药残留的安全指数值均小于1,安全影响较小;除毒死蜱、甲拌磷、敌敌畏这3种农药呈高中风险外,其他农药残留风险系数均小于1.5,为低度风险。结论 海南地区市售芹菜中普遍存在农药残留污染,但总体风险较低,不会对一般人群健康造成不可接受的风险,本研究可为海南地区芹菜的食品安全监管提供科学依据。     

超临界CO_2流体萃取与常规提取方法制备芹菜籽精油的比较

应用超临界CO2流体萃取(SFE-CO2)、同步水蒸气蒸馏-溶剂萃取(SDE)和有机溶剂提取(SE)方法提取芹菜籽中的香味成分,对不同提取方法制备的芹菜籽精油进行了得率、制备工艺、闻香评价、化学组成和卷烟加香应用效果等方面的对比研究。结果表明:SFE-CO2方法萃取的芹菜籽油得率(11 15%)接近SE方法得率(12 80%),远高于SDE方法得率(0 6%);从中鉴定出21种主要挥发性香气成分,占挥发油的92 98%。它们是瑟丹内酯、4,11 桉叶二烯、柠檬烯、1 (4 乙苯基)乙基酮、β 石竹烯、月桂烯、β 蒎烯、反 对 薄荷 2,8 二烯 1 醇、氧代石竹烯、罗勒烯、乙基芳樟醇、乙酸己酯、柠檬烯氧化物、反 香芹醇、顺 香芹醇、反 乙酸松香芹酯、反 乙酸香芹酯、α 石竹烯、β 芹子烯、β 榄香烯和邻苯二甲酸二丁酯。评香和卷烟应用实验显示:SFE-CO2萃取芹菜籽油的香气更自然浓郁,在卷烟中的应用效果优于SDE和SE方法制备的提取物,能有效改善卷烟吸味。     

芹菜叶中黄酮类化合物的提取与测定

文章以芹菜为研究对象,就其中总黄酮的提取分离和测定工艺进行了探讨。实验考察了单因素（提取溶剂浓度、物料比、回流提取时间和pH等）对总黄酮提取效果的影响,并在此基础上确定正交试验,得到了芹菜中总黄酮提取的最佳工艺条件∶40%（v/v）乙醇溶液,物料比（g/mL）1∶20,回流提取时间60 min,pH为6。得到总黄酮的含量为0.0794%。通过精密度实验和稳定性实验对测定方法进行评价。     

芹菜叶中叶绿素超声提取工艺的优化

为提高芹菜汁加工副产物中叶绿素的利用价值,以冻干芹菜叶为原料,在通过单因素试验优化冻干芹菜叶中叶绿素提取溶剂、料液比及超声辅助提取时间、温度对叶绿素提取效果影响的基础上,采用响应面设计进一步对超声辅助提取冻干芹菜叶中叶绿素的工艺参数进行优化,并与常规溶剂提取进行了比较。     

氯化钙处理对鲜切芹菜生理与品质的影响

目的研究不同浓度的氯化钙处理对室温下贮藏的鲜切芹菜生理品质的影响。方法分别采用化学滴定法、紫外分光光度法、称重法分析测定了鲜切芹菜可滴定酸、可溶性蛋白、还原糖、总糖、Vc、失重率等多项生理生化指标。结果芹菜经切割后在室温贮藏期间,可滴定酸、可溶性蛋白、还原糖、总糖、Vc含量呈现前期上升后期下降的趋势,失重率随贮藏期的延长逐渐上升;较低浓度氯化钙处理的可滴定酸、还原糖、总糖、Vc含量明显地高于对照和其他处理组,可溶性蛋白含量、失重率却低于对照组。结论氯化钙处理有效地保持了鲜切芹菜良好的生理品质,是一种简单、安全、有效的果蔬保鲜方法。