多菌灵、2、4—D虫胶涂料的毒性研究

虫胶防腐涂料是一种水果表面涂被剂,可增加果面光泽,在一定时期内可减少水分蒸发,加入多菌灵(MBC)和2、4-D(MCP)后,还有减少腐烂的作用,对防止果皮皱缩,保持风味,降低损耗,延长贮藏期,效果显著。但用这种涂料处理过的水果,会有少量多菌灵和2、4-D残留于水果中。经测定;苹果中多菌灵残留量为0．29~1．7ppm2．4-D为0．43~     

气质联用结合电子鼻表征不同温度热风干燥苹果脆片关键香气化合物

为明确富士苹果的关键香气化合物以及干燥温度对富士苹果关键香气化合物的影响,采用顶空固相微萃取气质联用（headspace solid-phase micro-extraction gas chromatography-mass spectrometer,HS-SPME-GC-MS）技术结合电子鼻对富士苹果鲜样、50、60、70和80 ℃热风干燥苹果脆片的挥发性化合物进行表征。结果表明,苹果鲜样和4种干燥样品共鉴定出64种挥发性化合物,包括酯类23种、醇类18种、醛类8种、烯烃类2种、酮类2种、内酯类3种、酸类1种、含硫化合物3种和杂环化合物4种。不同样品各类挥发性化合物的种类及含量均存在较大差异,鲜样香气化合物含量为397.059 mg/kg,不同温度热风干燥样品挥发性化合物含量由高到低分别为64.189 mg/kg（50 ℃处理）、57.703 mg/kg（80 ℃处理）、32.124 mg/kg（70 ℃处理）、32.020 mg/kg（60 ℃处理）。气味活性值（odor-active value,OAV）分析表明,苹果鲜样与热风干燥样品共有关键香气化合物8种,分别为α-法尼烯（12746.11~1597.75）、2-甲基丁酸己酯（755.62~6.90）、己醇（2988.00~168.54）、1-辛烯-3-醇（53.12~12.08）、壬醛（1534.99~47.36）、反式-2-壬烯醛（1202.98~189.38）、芳樟醇（1264.30~212.75）和6-甲基-5-庚烯-2-酮（11.27~3.90）。除此以外,热风干燥样品独有的关键香气化合物包括2-甲基-1-丁醇（32.26~7.16）、3-甲基-4-庚醇（14.39~6.90）、苯乙醇（11.11~4.67）、辛醛（211.25~84.36）、3-羟基-2-丁酮（64.57~21.86）、3-甲硫基丙醇（13.52~5.88）和2-戊基呋喃（26.44~14.88）。电子鼻分析表明鲜样与热风处理苹果脆片香气轮廓存在差异,通过主成分分析（principle component analysis,PCA）可以对鲜样和脱水苹果脆片进行有效区分。综合考虑香气、能耗,相比于50 ℃热风处理,80 ℃可以在短时间内使苹果片呈现热风脱水制品的特征性风味。因此,80 ℃热风干燥条件最佳。     

三个国家Cascade酒花香气对比分析

采用顶空固相微萃取气相色谱-质谱（HS-SPME-GC-MS）联用的方法分析测定中国、美国和新西兰Cascade颗粒酒花中香气化合物的组成,分别与Cascade酒花在麦汁煮沸时添加酒花的酒样香气化合物和在啤酒储存期干投酒花的酒样香气化合物进行对比分析,同时分别进行感官品评。结果表明,三个国家Cascade酒花的香气化合物相比较,新西兰Cascade酒花在麦汁煮沸过程中添加,香气化合物减少17种,增加3种,在啤酒储存期干投香气物质减少19种,增加12种;美国Cascade酒花在麦汁煮沸过程中添加,香气化合物减少18种,增加2种,在啤酒储存期干投香气物质减少12种,增加12种;中国Cascade酒花在麦汁煮沸过程中添加,香气化合物减少12种,增加5种,在啤酒储存期干投香气物质减少11种,增加14种。减少的主要是萜烯类物质,增加的主要是醇和酯类物质。感官品评方面,在麦汁煮沸过程中添加Cascade酒花,中国的Cascade酒花具有突出的柑橘、柠檬、苹果或桃子的香味;在啤酒储存期干投Cascade酒花,生成较多的醇类物质,酒花的利用率较高。     

广州市场部分蜜饯中SO_2残留量调查

采用国标GB／T5009．34——2003第2种方法（蒸馏法）对广州市场上7类共43个蜜饯产品中的SO2残留量进行分析测定,同时测定样品中的糖度、总酸度和水分含量等指标。结果显示,SO2残留量超过国家GB2760——2007《食品添加剂使用卫生标准》规定标准（0．35g／kg）的有10个产品,占调查总数的23．26％,残留量为0．4704—3．8411g／kg;残留量超标严重的两个波萝果脯产品分别超出规定标准的9．08倍和10．97倍;合格产品的SO2残留量为0．0005～0．2530g／kg。调查结果表明,同类产品不同厂家之间的SO2残留量差异较大。     

三重四级杆串联质谱法测定糯米(黄酒原料)中多菌灵残留量的不确定度分析

建立了评定GB/T 20770—2008《粮谷中486种农药及相关化学品残留量的测定——液相质谱联用法》中影响测量多菌灵不确定度多因素数学模型,考察了样品前处理及质谱测定的各个环节,根据建立的模型计算评定测量不确定度的各分量。采用该方法测得糯米中多菌灵的残留量为26.8×10-3±0.78×10-3mg/kg。分析表明,多菌灵残留量测定的不确定度主要来源于标准溶液的配制、样品前处理制备过程和样品溶液的平行测定差异。经计算,在置信概率P=95%时,运用该方法测定试样中多菌灵残留的相对标准合成不确定度为1.46%,标准不确定度为0.39×10-3mg/kg,扩展不确定度(K=2)为0.78×10-3mg/kg。     

预处理对增加红富士苹果细胞壁物质降解和出汁率的影响

为了通过简便易行的预处理增强果实细胞壁物质降解,提高苹果果实出汁率。文中测定了500mg/L乙烯利(E_1)和100mg/L乙烯利配合60℃热水(E_2)处理,对红富士果实堆放期细胞壁酶活性、细胞壁物质含量和出汁率的影响。结果表明:E_1使其果胶甲酯酶(PME)、纤维素酶(CS)活性高峰分别比对照提前6、3d,多聚半乳糖醛酸酶(PG)活性在前15d持续高于对照,木聚糖酶(Xyl)活性基本不变;处理12d后,果实细胞壁多糖中果胶类多糖、半纤维素类多糖和细胞壁残渣多糖含量分别下降到对照的80.1%、70.4%和75.7%;处理后9～18d,红富士苹果的出汁率较对照提高2.3%～4.0%;E_2抑制了果实PME活性,却普遍增强了0～6d内PG、Xyl、CS活性,亦促进了各类细胞壁物质的降解,0～9d内果实出汁率较对照高3.2%～7.1%。     

设施调控夜间温度对赤霞珠葡萄果实品质的影响

为研究夜间温度对赤霞珠浆果品质的影响,采用设施调控夜间温度模拟夜间高温（high temperature at night,HT,平均温度21.8 ℃）和夜间低温（low temperature at night,LT,平均温度17.1 ℃）处理,与自然环境（CK,平均温度18.9 ℃）比较。从果实转色前连续35 d对设施进行夜间控温并监测温湿度,测定不同处理浆果品质及成熟时挥发性香气物质,并分析差异。结果表明：果实转色后,LT加速了可溶性糖、花色苷和类黄酮的积累,成熟时分别较CK高11.7%、51.7%和27.9%;LT减缓了可滴定酸和单宁的降解,成熟时分别较CK高16.1%和16.5%;HT除显著降低果实总酚外,对其他品质指标均没有影响。夜间温度对成熟时果实挥发性香气化合物种类和各成分占比影响显著,表现为共检出香气成分103 种,LT、HT和CK分别检出44、38、43 种,其中共有香气成分为11 种;HT减少了香气物质的种类数,增加了醛类化合物的相对含量;LT提高了醛类、萜烯类和酯类化合物的相对含量;夜间温度处理均降低了醇类化合物的相对含量。因此,LT有助于提高赤霞珠果实品质,HT会降低果实品质。     

冷冻处理对荔枝香气成分的影响

以晚熟糯米糍荔枝品种为试材,采用顶空固相微萃取（HS-SPME）提取新鲜糯米糍荔枝果肉和冷冻处理60d后荔枝果肉的香气成分,用GC-MS联用仪对香气化合物进行分析鉴定。结果表明,冷冻处理前后荔枝在香气组成和含量上具有显著差异。新鲜糯米糍荔枝和冷冻糯米糍荔枝分别鉴定出36、29种香气成分。相对总含量分别为96．97％、99．98％,具有8种共有香气成分。烯类是荔枝果肉风味的主要组成成分。经冷冻处理后,醇类和烷烃类物质相对含量明显增加,酯类物质相对含量明显减少。此外,在冷冻处理后的荔枝果肉中还检测到了醚类、醛类和羧酸类物质各1种。     

即食秋刀鱼加工过程中挥发性成分变化规律

目的：采用顶空固相微萃取法结合气相色谱质谱联用技术（HS-SPME-GC-MS）分离鉴定不同加工阶段秋刀鱼（Cololabis saira）的挥发性成分。方法：用气味阈值计算相对气味活度值（ROAV）,确定样品的关键风味物质;利用主成分和变量投影重要性分析值（VIP）分析不同阶段的特征风味及化合物。结果：秋刀鱼样品中共检出63种挥发性成分,醛类是主要的风味物质。6个关键风味化合物分别为（E,Z）-2,6-壬二烯醛、辛醛、3-甲硫基丙醛、（Z）-4-庚烯醛、（E,E）-2,6壬二烯醛和1-辛烯-3醇。结论：腌制前的秋刀鱼香气特征为蘑菇香,腌制后样品的香气特征为鱼香和果香,油炸处理的秋刀鱼风味物质最为丰富,香气特征是油脂香和肉香。     

不同陈酿时间苹果白兰地主要香气成分变化分析

分析苹果白兰地橡木桶陈酿过程中挥发性香气成分的变化,采用液液萃取和气相色谱-质谱联用技术对不同陈酿时间的苹果白兰地中风味物质进行测定,并就风味物质进行聚类分析。结果表明,陈酿过程中苹果白兰地共鉴定出90种化合物,其中酯类物质43种,醇类物质32种,酸类物质15种。随着陈酿时间的延长,苹果白兰地共同酯类及酸类香气物质的种类数量和总含量呈现增加的趋势,共同醇类香气物质总含量呈现减少的趋势;而酸类香气成分的种类数量呈现先增后减的趋势。陈酿过程中,苹果白兰地中的香气成分发生着生成、更替、消失的动态变化。聚类分析结果表明,整个陈酿过程挥发性物质随变化规律聚集为3类,不同大类的苹果白兰地呈现出不尽相同的风味特征。     

Effect of home processing on the distribution and reduction of pesticide residues in apples

The effect of home processing (washing, peeling, coring and juicing) on residue levels of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim in apple segments was investigated. The pesticide residues were determined by UPLC-MS/MS and GC with a flame photometric (FPD) and electron capture detection (ECD). The results indicated that the pesticide residue levels in the apple peel and core were higher compared with in the apple flesh. After peeled and cored apple was processed into apple juice and pomace, chlorpyrifos, β-cypermethrin and tebuconazole were concentrated in the apple pomace. However, residues of acetamiprid and carbendazim were exceptions. The apple pomace was free of acetamiprid, which was mainly present in the apple juice. After washing the mean loss of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim from apples under recommended dosage and twofold higher dosage were 17–21%, 6.7–7.1%, 13–32%, 42–67% and 47–50%, respectively. The pesticide residues were significantly reduced in the edible part of the apple except for β-cypermethrin during peeling and coring process. The removal effect of apple juicing was found to be the most pronounced on β-cypermethrin residue, which was reduced in the range of 81–84%, and the reductions of chlorpyrifos, tebuconazole, acetamiprid and carbendazim upon apple juicing were in the range of 15–36%.     

Effect of home processing on the distribution and reduction of pesticide residues in apples

The effect of home processing (washing, peeling, coring and juicing) on residue levels of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim in apple segments was investigated. The pesticide residues were determined by UPLC-MS/MS and GC with a flame photometric (FPD) and electron capture detection (ECD). The results indicated that the pesticide residue levels in the apple peel and core were higher compared with in the apple flesh. After peeled and cored apple was processed into apple juice and pomace, chlorpyrifos, β-cypermethrin and tebuconazole were concentrated in the apple pomace. However, residues of acetamiprid and carbendazim were exceptions. The apple pomace was free of acetamiprid, which was mainly present in the apple juice. After washing the mean loss of chlorpyrifos, β-cypermethrin, tebuconazole, acetamiprid and carbendazim from apples under recommended dosage and twofold higher dosage were 17-21%, 6.7-7.1%, 13-32%, 42-67% and 47-50%, respectively. The pesticide residues were significantly reduced in the edible part of the apple except for β-cypermethrin during peeling and coring process. The removal effect of apple juicing was found to be the most pronounced on β-cypermethrin residue, which was reduced in the range of 81-84%, and the reductions of chlorpyrifos, tebuconazole, acetamiprid and carbendazim upon apple juicing were in the range of 15-36%.     

基于多元分析的11种烟台中、晚熟品种苹果香气成分比较

为了探明烟台中、晚熟苹果品种间主要香气成分的差异,采用顶空固相微萃取(HS-SPME)结合气相色谱与质谱联用(GC-MS)对11种烟台中、晚熟品种苹果的香气成分进行检测分析,并对不同品种的苹果以及其香气成分的种类进行主成分分析和聚类分析。结果表明,从11种苹果中共检测出59种香气成分,其中21种成分为所有品种苹果所共有,在共有香气成分中,乙酸、丁酸、己酸的酯类化合物,己醛(包括2-己烯醛)与一些高级醇含量较高。主成分分析表明,阳光苹果、丹霞苹果综合得分较高,极早熟富士苹果综合得分最低,得分排名反映出苹果品种之间主要香气成分的差异大小。聚类分析表明,11种苹果可分为四类:第一类为烟富三、斗南、甘红、极早熟富士、皮诺娃、烟富一、最良短富;第二类为丹霞、阳光;凉香和华帅分别自为一类。经过两种分析方法有效结合,筛选得到的丹霞、阳光、凉香、华帅四种苹果香型特点更为突出,为今后品质育种亲本选择提供依据。     

超低氧贮藏富士苹果的初步研究

以红富士苹果(Fuji apple)为实验材料,研究了超低氧(体积分数1.6%±0.1%)保鲜方法对富士苹果贮藏品质的影响。实验结果表明:与气调和冷藏相比,超低氧保鲜的苹果呼吸强度更低,可更好地保持苹果的硬度、可溶性固形物含量,减少果实酸、糖及Vc含量的损失。各处理中,O2体积分数为1.6%±0.1%环境下的苹果各项生理指标最好,虎皮病发病率最小,好果率最高,但是苦痘病发病率较高。与对照相比,经过超低氧处理的果实的货架期品质同样最好。     

5种苹果微粉的理化品质与行为特征

为了制备高品质的苹果纯粉,给苹果制粉加工和新产品开发提供理论支持,以国家苹果种质资源圃中常见的5个加工兼鲜食苹果品种(长富2号、寒富、黄元帅、国光、秦冠)为原料,采用中短波红外干燥联合普通粉碎技术制备苹果微粉,对苹果微粉的理化指标及加工过程中的行为特征进行测定与分析,采用主成分分析法对苹果微粉的品质评价指标进行简化。结果显示,在理化指标方面,色泽上寒富苹果微粉的亮度显著高于其他品种苹果微粉,秦冠苹果微粉的亮度最小;长富2号微粉的总酚含量最高;富士系苹果微粉的总糖含量最高。在行为特征方面,长富2号和寒富在高应力条件下的黏结性较小且在输送过程中表现较好。对测定的20项指标依据主成分解释总变量和碎石图,从中提取了反映原来变量90.38%信息的3个主成分,综合各项指标得出富士系苹果是制备高品质苹果微粉的优选品种。     

Carbendazim and metalaxyl residues in post-harvest treated apples

Bramley apples were treated with Ridomil mbc 60 WP, containing carbendazim and metalaxyl, at half and full rate application at 10 and 20°C, and with diphenylamine to control disease during storage. Carbendazim and metalaxyl residues were determined by HPLC and GC/MS, respectively, in apple core, flesh and peel at the initial time, 3 and 6 months after storage under controlled atmosphere conditions of 4.5°C, 5% CO₂ and 1% O₂. The concentration of carbendazim residues in apple flesh was ≤ 0.43 mg kg^-1 in all treatments; the mean concentrations in apple core and peel were 2.2 ±1.1 and 5.2 ±2.2 mg kg^-1, respectively. The MRL for carbendazim in apple was 2.0 mg kg^-1. The concentration of metalaxyl residues in apple flesh was ≤ 0.22 mg kg^-1; the mean concentrations in apple core and peel were 0.41 ±0.18 and 0.79 ±0.94 mg kg^-1, respectively. The MRL for metalaxyl in apple was 1.0 mg kg^-1. The temperature of the fungicide solution had little effect on the carbendazim residues but did have some effect on metalaxyl residues. Carbendazim residue content per apple was decreased when diphenylamine was included. A change in the ratio of carbendazim to metalaxyl was noted in the flesh, core and peel of the stored apple. The ratio of carbendazim to metalaxyl was 5:1 in the fungicide mix as applied. The ratio remained fairly constant in the core during storage. However, the ratio changed significantly in the peel and, to a lesser extent, and in a different direction, in the flesh. In the peel, the ratio was around 15:1 at 3 months of storage and 12:1 after 6 months of storage, whereas for flesh the ratios were 2:1 and 4:1, respectively.     

Wettability of Chitosan Coating Solution on'Fuji' Apple Skin

Wettability of chitosan coating solutions on‘Fuji’ apple skin in different surfactant concentration (Tween 80: 0, 10, 100, 1000 ppm) was investigated using the Du Nouy ring method and the sessile‐drop method. The surface property of‘Fuji’ apple skin as a coated solid surface was characterized by the Zisman plot. The critical surface tension of‘Fuji’ apple skin was 18.7 dyne/cm. The surface tension of the chitosan coating solution was too high (61.5 dyne/cm) to wet the apple skin. Tween 80 as surfactant in water‐borne coatings reduced the surface tension of the coating solution and enhanced its wettability. Surface morphology of the coated film was observed by scanning electron microscope. Surfactant driven autophilicity improved the adhesive force between coating solution and associative apple skin, and decreased the contact angle of coating solution.     

茉莉酸甲酯处理对鲜切苹果生理生化变化的影响

以鲜切富士苹果为试材,研究了不同浓度的茉莉酸甲酯处理对常温下贮藏的鲜切苹果生理生化的影响。在贮藏过程中分析测定了鲜切苹果PPO和POD酶活性、多酚、还原糖和可溶性蛋白质含量等生理生化指标。结果表明,与对照相比,茉莉酸甲酯处理能抑制PPO和POD酶活性,多酚、总糖和可溶性蛋白质含量也发生了不同程度的提高,尤其以低浓度的茉莉酸甲酯处理贮藏效果更好,可保持鲜切苹果较好的贮藏品质。     

苹果组织pH值对扩展青霉生长及棒曲霉素分泌的影响研究

目的 探究苹果组织pH值对扩展青霉生长及棒曲霉素(patulin, Pat)分泌的影响。方法 选取3种不同酸度的苹果(红富士、青金帅、国光, pH值分别为3.83、3.61、3.43)作为实验材料, 分析扩展青霉在苹果不同部位上的生长规律, 以及毒素的分泌情况。结果 苹果组织pH值能够影响扩展青霉的致病力, 苹果病斑直径、相同部位扩展青霉数量及Pat含量与苹果组织pH值呈正相关; 苹果果实硬度也对扩展青霉的生长和Pat分布有一定影响, 硬度较低的青金帅苹果健康组织中扩展青霉菌落数量和Pat含量高于红富士和国光苹果。 结论 苹果组织pH值能够影响扩展青霉菌的致病力, 品种对扩展青霉侵染及毒素产生也有较大的影响。     

Changes of contents and antioxidant activities of polyphenols during fruit development of four apple cultivars

Polyphenols are functional components in apples and can be separated into four groups by Sephadex LH-20 as epicatechin, procyanidolic oligomers, chlorogenic acid and procyanidolic polymers. Antioxidant activities of each group were determined by FRAP and DPPH radical scavenging assay. It was found that procyanidolic oligomers and procyanidolic polymers influenced the total polyphenols content (measured by Folin–Ciocalteu method) much more in Jonagold, Golden Delicious, Fuji and Guoguang four apple cultivars. The Fe-reducing activity of procyanidolic oligomers in the four apple cultivars increased significantly during the development while the other three compounds changed irregularly. And the Fe-reducing activities of epicatechin and procyanidin contributed much more to the total Fe-reducing activities during the fruit development in the four apple cultivars. The DPPH scavenging activities of four compounds in Jonagold and Golden Delicious decreased during fruit development and that of Fuji and Guoguang changed irregularly. Chlorogenic acid was the main contributor in Jonagold, Golden Delicious and Fuji to the total scavenging activity. In Guoguang, it was procyanidolic oligomers that contributed much to the total scavenging activity.