五种枣成分及功能研究

对五种枣的主要成分、无机元素、维生素以及总酚含量进行分析研究,并探讨总酚含量与抗氧化的关系.五种枣中总糖含量为80.86%～85.63%,还原糖含量为57.61%～77.93%,纤维素含量为6.13%～8.90%,蛋白质为4.75%～6.86%,脂肪含量为0.37%～1.02%,金丝小枣非还原糖的含量较高,其蛋白质和灰分的含量较低,故适合作为提取枣多糖的原料.五种枣中钾、钙、镁的含量较高,铁、钠、锌、铜的含量较低,硒未检出.五种枣中总酚含量为5.18～8.53mg/g,其中牙枣和尖枣因总酚含量较高,故适合作为提取酚类化合物的原料;五种枣的总酚含量与总的抗氧化能力没有相关性.     

Nutritional composition of five cultivars of chinese jujube

The proximate composition of five cultivars of Chinese jujube, along with mineral, vitamin and total phenolic contents were determined. Investigations showed that Chinese jujube contained 80.86–85.63% carbohydrate, 57.61–77.93% reducing sugar, 0.57–2.79% soluble fibre, 5.24–7.18% insoluble fibre, 4.75–6.86% protein, 0.37–1.02% lipid, 17.38–22.52% moisture and 2.26–3.01% ash. The soluble sugars of Chinese jujube included fructose, glucose, rhamnose, sorbitol and sucrose. Fructose and glucose were identified as the major sugars while sorbitol was present in much lesser amounts. Potassium, phosphorus, calcium and manganese were the major mineral constituents in Chinese jujube. Iron, sodium, zinc and copper were also detected in appreciable amounts. The contents of vitamin C, thiamine and riboflavin were found to be 192–359, 0.04–0.08 and 0.05–0.09 mg/100 g, respectively. Total phenolic contents ranged from 5.18 to 8.53 mg/g. No correlation between total phenolic contents and antioxidant capacities or antioxidant capacities and vitamin C contents of Chinese jujube was found.     

三种洋葱营养成分分析

对三种洋葱的主要营养成分、矿物质和黄酮类化合物含量进行分析研究,并探讨黄酮类化合物含量与抗氧化的关系。三种洋葱中水分含量为88.3%～92.7%,碳水化合物为7.73%～8.56%,蛋白质为1.12%～1.71%,脂肪为0.23%～0.41%,其中,白皮洋葱的脂肪含量较高,适合作为提取洋葱油的原料。三种洋葱中黄酮类化合物含量为592.3～913.2mg/kg,紫皮洋葱的黄酮类化合物含量最高,适合作为提取黄酮类化合物的原料,而且紫皮洋葱的产量较高,种植面积较大,很有开发前景;三种洋葱的黄酮类化合物含量与总的抗氧化能力没有相关性。三种洋葱矿物质元素组成相似,钾含量最高,铜含量最低。     

Evaluation of pesticide residue dynamics in Chinese cabbage,head cabbage and cauliflower

ABSTRACT

Pesticide residues from the time of application until harvest were analysed for 20, 17 and 18 active insecticidal and fungicidal substances in Chinese cabbage, head cabbage and cauliflower, respectively. In total, 40 mathematical models of residue degradation were developed using a first-order kinetic equation, and from these models it was possible to forecast the action pre-harvest interval for a given action threshold for low-residue production in Brassica vegetables as a percentage of the maximum residue level. Additionally, it was possible to establish an action pre-harvest interval based on an action threshold of 0.01 mg kg^?1 for the production of Brassica vegetables for baby food. Among the evaluated commodities, the speed of residue degradation was highest in head cabbage, medium in Chinese cabbage and lowest in cauliflower. The half-lives of pesticide in various vegetables were also determined: they ranged from 1.55 to 5.25 days in Chinese cabbage, from 0.47 to 6.54 days in head cabbage and from 1.88 to 7.22 days in cauliflower.     

五种枣提取物抗氧化活性的比较

研究了五种枣提取物的抗氧化活性,并与维生素E(VE)的抗氧化性相比较.结果表明:五种枣提取物抗氧化能力不同,五种枣提取物抗亚油酸过氧化能力、还原力、DPPH·清除率的强弱顺序相同,由强到弱依次为:金丝小枣、牙枣、尖枣、骏枣和三变红枣.其中金丝小枣、牙枣、尖枣抗氧化能力均大于VE.Duncan新复极差统计分析表明,金丝小枣、牙枣、VE之间的抗氧化能力存在显著性差异(P<0.05),而尖枣和VE之间没有显著性差异(P>0.05).此外,五种枣提取物的总酚含量与总的抗氧化能力没有相关性.     

五莲植烟土壤及烟叶中重金属、农药残留状况研究

采用定点调查方法研究了五莲植烟土壤、烟叶中重金属、农药残留状况。土壤中的铅、镉、汞、六六六的含量指标低于土壤自然背景值,大部分土壤中的滴滴涕含量也低于土壤自然背景值。烟叶中铅、镉、汞含量处于较低水平,有机氯、有机磷、拟除虫菊酯等杀虫剂、杀菌剂烟叶中残留普遍较低,部分有机磷杀虫剂残留相对较高。五莲烟区具有发展低残留优质烟叶的优越自然条件,但需进一步规范农药的使用。     

澳洲坚果粕营养成分测定与氨基酸组成评价

目的:研究分析澳洲坚果粕营养成分的含量与组成。方法:采用氨基酸自动分析仪、凯氏定氮法及蒽酮-硫酸法等方法对澳洲坚果粕中的氨基酸、蛋白质、碳水化合物等营养成分进行了测定。应用氨基酸比值系数法,以WHO/FAO氨基酸参考模式为评价标准,对必需氨基酸的组成进行了评价。结果:澳洲坚果粕含脂肪17.22%、蛋白质24.90%、碳水化合物24.78%、氨基酸17种,总量为17.84%。其必需氨基酸的构成比例基本符合食品法典委员会(FAO/WHO)的标准,氨基酸的比值系数分(SRC)为86.95。结论:澳洲坚果粕营养丰富,人体必需氨基酸种类齐全,配比均衡,是有利于人体氨基酸营养平衡的优质食品原料。     

Gross composition,amino acid,phytic acid and trace element contents of thirteen cowpea cultivars and their nutritional significance

Thirteen cultivars of cowpea (Vigna unguiculata (L) Walp) were analysed for their proximate composition, amino acid, trace element and phytic acid contents. Crude protein values ranged from 206·8 to 283·8 g kg^?1 DM. The mean contents (g kg^?1) of other major nutrients were ether extract, 18·6; ash, 38·8; total dietary fibre, 121·8 and carbohydrates, 573·4. When compared with the provisional amino acid scoring pattern of FAO, all cultivars were low in methionine and high in lysine, isoleucine, leucine and phenylalanine plus tyrosine. Values for threonine and valine were variable compared with the pattern. The range of values for the chemical score was 0·61–0·74. Phytic acid values ranged from 5·10 to 10·27 g kg^?1, and the phytate: zinc molar ratios were all higher than that (15:1) above which zinc deficiency can be induced. Most of the trace elements showed wide variation in their occurrence among the cultivars. The values for zinc and iron showed less variation. The toxic elements mercury and selenium were present in varying amounts in more than half of the cultivars while tin was found in only one variety.     

西藏察隅龙爪稷营养成分、重金属含量与农药残留分析

以西藏察隅龙爪稷为研究对象,对其营养成分、重金属含量与农药残留进行测定,并采用国际通用的评价方法对其营养进行评价。结果表明:龙爪稷籽粒蛋白质含量7.31%,脂肪含量1.2%;矿物质元素K、Ca、Mg、Fe、Zn含量分别为3 281.8 mg/100 g、2 259.5 mg/100 g、1 403.9 mg/kg、15.2 mg/kg与13.9 mg/kg,高于普通谷物;龙爪稷含有18种氨基酸,其中必需氨基酸8种,占氨基酸总量的39.80%,必需氨基酸评分60,必需氨基酸指数87.26,第一限制性氨基酸为赖氨酸;此外,龙爪稷中重金属As、Hg、Pb、Cd均未检出,188种农药未检出,食用安全性高。     

纤维素酶-木聚糖酶对红枣渣膳食纤维的酶法改性

以红枣渣为原料,分别探讨了纤维素酶和木聚糖酶单酶加酶量、酶解时间、酶解温度、酶解pH对红枣渣可溶性和不溶性纤维得率的影响;在此基础上,以2种酶的添加量和酶解时间为变量,利用多因素复合试验设计原理和分析方法,得到枣渣纤维的酶法改性的最佳条件为:纤维素酶添加量0.29%、木聚糖酶添加量0.21%、酶解时间49.23 min。通过酶法改性,可将枣渣纤维的可溶性纤维的比例由6.79%提高到10.15%,以使可溶性纤维与不溶性纤维接近1∶3的最佳比例。     

枣渣中黄酮和多糖连续提取工艺研究

应用微波-超声波辅助乙醇法和水提法分别提取枣渣总黄酮和多糖。实验结果表明:枣渣黄酮提取的较优条件为:提取温度65℃、超声提取时间30min、固液比1∶20、乙醇浓度70%,在此工艺条件下黄酮含量为1.50%。枣渣多糖最佳提取工艺为:浸提温度90℃,浸提时间3h,固液比1∶20,粗多糖提取率2.17%,多糖含量达63.64%。     

Chemical composition and nutritional characteristics of some hull less and hulled barley cultivars grown in India

Three hull less and nine hulled barley cultivars were grown during 1995-96 at Research Farm, CCS Haryana Agricultural University, Hisar, India and were used for chemical analysis such as nutritional and antinutritional parameters. Dolma, a hull less barley cultivar had higher contents of protein, fat, starch, in vitro digestibility of protein and starch, in vitro availability of Ca, Fe and Zn. Hulled cultivar BH-331 showed higher values of phytic acid (925 mg/100 g), polyphenols (625 mg/100 g) and amylase inhibitor activity (169 AIU) which might have contributed towards poor in vitro digestibility of Ca, Fe and Zn. Phytic acid and polyphenols manifested significantly negative correlation with in vitro availability of Ca, Fe and Zn and protein digestibility. Whereas amylase inhibitor activity showed significant and negative correlation (-0.992) only with starch digestibility.     

Bioactivity and chemical composition of blackcurrant (Ribes nigrum) cultivars with and without pesticide treatment

Eleven blackcurrant cultivars grown with pesticide (PT) and without pesticide treatment (PF) were evaluated to compare the differences in plant growth and physical condition, total anthocyanin content, ascorbic acid content, total antioxidant capacity, effect on prostaglandin E2 (PGE2) production and anticancer cell proliferation activities. Results showed that the yield and growth of PT blackcurrants were higher. However, PF blackcurrants contained a higher amount of ascorbic acid, and displayed an increased inhibition against cancer cells compared to PT blackcurrants, indicating that PF blackcurrants have an increased potential to deliver health-promoting benefit for consumers. Significant differences were observed between blackcurrant cultivars in relation to plant growth and physical condition, total anthocyanin content and PGE2 assay, highlighting the importance of cultivar selection.     

Nutritional evaluation of kidney beans (Phaseolus vulgaris): chemical composition, lectin content and nutritional value of selected cultivars

The chemical composition, lectin content and nutritional value of selected cultivars of kidney beans (Phaseolus vulgaris) were determined. Mainly due to different amounts of reserve globulins deposited, seed N content varied between 3.4 and 5.0%. The amino acid composition and the corresponding chemical score values of 40-60 however, were similar for all the beans, with the sulphur-containing amino acids limiting. Despite similarities in composition, 11 out of the 13 cultivars examined were highly toxic for rats in the raw state. These were all found to contain high concentrations of haemagglutinating lectins (over 10% of the total protein). On the other hand, two low-lectin bean varieties, Pinto III and Great Northern, had no appreciable disruptive effects on the intestines and were essentially non-toxic for rats.     

苹果渣及枣渣培养嗜酸乳杆菌发酵条件的研究

利用嗜酸乳杆菌发酵苹果鲜渣与枣渣的浸提液,以发酵液中活菌数为指标,与MRS培养基进行对比试验,结果表明,原料中枣渣含量21.13％,浸提后补加2.02％蛋白胨,1.41％酵母粉,发酵25.59h,活菌数可达到2.13×109cfu/mL,因此,以苹果鲜渣与枣渣的浸提液作为发酵培养基生产嗜酸乳杆菌具有可行性.     

红枣芦荟营养保健香肠的开发研究

将红枣粉和芦荟汁添加到香肠制品制成红枣芦荟营养保健香肠。利用正交试验及感观评定确定除猪肉外的主要原料的最佳配比为：红枣20％，芦荟15％、大豆蛋白4％、马铃薯淀粉8％(各原料的百分比均为占原料肉的百分比)经产品质量检验，各项指标均符合肉与肉制品国家标准。     

粗柄鸡枞菌子实体不同部位营养成分及重金属测定

以野生粗柄鸡枞菌子实体为实验材料,通过化学分析、仪器分析法测定了粗柄鸡枞菌菌盖、菌柄和菌根干粉的营养成分。结果表明,粗柄鸡枞菌子实体的不同部位的营养成分含量有差异,总糖、还原糖、粗脂肪、5种矿物元素(钾、钠、铁、镁、锌)在菌盖中含量较高,尤其菌盖中铁含量(1 471mg/kg)分别是菌柄的3倍,菌根的4倍;粗蛋白在菌柄中含量较高;灰分、粗纤维、2种元素(锰、铜)在菌根中含量较高。粗柄鸡枞菌不同部位的砷、汞元素含量无显著性差异(P0.05),铅元素在菌根中含量较高,但均符合国家食用菌卫生标准中限量范围。     

Effect of paste processing on residue levels of imidacloprid,pyraclostrobin, azoxystrobin and fipronil in winter jujube

The changes of imidacloprid, pyraclostrobin, azoxystrobin and fipronil residues were studied to investigate the carryover of pesticide residues in winter jujube during paste processing. A multi-residue analytical method for winter jujube was developed based on the QuEChERS approach. The recoveries for the pesticides were between 87.5% and 116.2%. LODs ranged from 0.002 to 0.1 mg kg^–1. The processing factor (Pf) is defined as the ratio of pesticide residue concentration in the paste to that in winter jujube. Pf was higher than 1 for the removal of extra water, and other steps were generally less than 1, indicating that the whole process resulted in lower pesticide residue levels in paste. Peeling would be the critical step for pesticide removal. Processing factors varied among different pesticides studied. The results are useful to address optimisation of the processing techniques in a manner that leads to considerable pesticide residue reduction.     

生物传感器在农药残留分析中的研究现状及展望

综述了几类生物传感器包括酶传感器、微生物传感器、免疫传感器在农药残留分析中的应用进展,并探讨了其发展趋势.