臭椿树皮提取物对烟草甲成虫的生物活性

以乙醚为提取溶剂采用索氏法提取臭椿树皮,研究了其提取物对烟草甲成虫的生物活性。结果表明:臭椿树皮乙醚提取物对烟草甲成虫表现出较强的驱避作用,处理24、48和72h后,对烟草甲成虫的驱避率分别达到93.71%、87.75%和76.14%;对烟草甲成虫的触杀作用较弱,但对烟草甲成虫的熏蒸作用较强,在1.00×10-4的处理浓度下熏蒸48h后其校正死亡率可达到100%。     

不同提取方法对牛蒡中类胡萝卜素含量的影响

实验考察了普通蒸馏法、索氏抽提法和超声波-微波提取法对牛蒡中类胡萝卜素含量的影响。结果表明:普通蒸馏法最佳提取条件为70℃、牛蒡粉60目、料液比1∶30、提取率697.11μg/100g;索氏提取法最佳提取条件为70℃、牛蒡粉60目、提取5h、提取率959.16μg/100g;超声波-微波萃取法最佳提取条件为超声波40W、牛蒡粉60目、料液比1∶30、微波功率300W,提取50s,提取率1269.77μg/100g。     

癞葡萄水提物的降糖效果研究

为研究癞葡萄水提物对正常小鼠及四氧嘧啶型糖尿病小鼠血糖浓度的影响,将不同剂量(250mg/kg体重、500mg/kg体重和750mg/kg体重)的水提物灌胃给予禁食12h的正常小鼠和四氧嘧啶型糖尿病小鼠。试验结果表明,癞葡萄水提物对正常小鼠的血糖浓度没有影响,而对四氧嘧啶型糖尿病小鼠的血糖浓度有显著影响。其中500mg/kg剂量组糖尿病小鼠的血糖值在灌胃4h后较相应的初始血糖值下降45.28%,糖尿量提高38.39%;给予500mg/kg水提物治疗15d后,糖尿病小鼠血糖值较治疗前下降59.88%,同时对小鼠体重的恢复有一定的促进作用。结果表明癞葡萄水提物对四氧嘧啶型糖尿病小鼠具有良好的预防和治疗效果。     

海带多糖的提取及降血糖口含片的研制

海带中含有碘、多糖等活性物质,尤其海带多糖具有降血糖、降血脂等保健功能。研究了海带粗多糖二次水提-碱提提取工艺和海带降血糖口含片配方及加工工艺。研究结果表明,提取最佳工艺为藻体1.5%Na2CO3溶液1∶8、提取温度60℃、提取时间1.5h。海带降血糖口含片配方为海带粗多糖粉40%、蔗糖粉58%、柠檬酸1%、硬脂酸镁1%。     

DNA微阵列在食品营养与安全中的应用与展望

DNA微阵列是一种高通量基因检测和分析技术,主要概括介绍DNA微阵列在营养基因组学、食源性病原体检测、转基因食品和饮食补充剂安全性评价中的应用。     

植物提取物用于果蔬植物防腐保鲜研究进展

致腐菌是诱发果蔬采后病害,造成果蔬腐败变质的主要原因。现对植物提取物对果蔬致腐菌的抑制作用,不同提取方法对致腐菌的抑制效果和提取物用于果蔬防腐保鲜的研究进展作一综述。     

纺织品水萃取液甲醛含量的测定

按照GB/T2912.1-1998《纺织品甲醛的测定第一部分游离水解的甲醛(水萃取法)》测定纺织品、服装上游离甲醛的含量时,为减少数据的离散性,提高测试结果的正确程度,详细讨论了测试过程中所用水质、试剂、溶液的配制与标定、试样的准备、仪器的校正及有效数字的保留等对测定结果的影响。     

超声波辅助提取山豆根苦参碱研究

首次报道山豆根苦参碱的超声波辅助提取方法。采用单因子试验和L9(34)正交试验设计,研究了超声波功率、超声波时间、超声波温度、乙醇浓度、液料比、浸置时间、提取液pH和提取次数对山豆根苦参碱提取的影响。结果表明,影响苦参碱得率的主次因素为超声波时间、超声波温度、超声波功率及浸置时间;经正交试验确定山豆根苦参碱最佳提取工艺条件为料液比为50、超声波时间为120min、超声波温度为70℃、超声波功率为300W、浸置时间为30min、乙醇浓度为60%、提取液pH为13、提取1次,在此最佳工艺条件下,山豆根苦参碱的得率为0.562%。     

Improvement and induction property of radiation-responsive promoter through DNA shuffling of 5′-flanking regions of the human p21 gene

A promoter that augments gene expression in response to stimulation of ionizing radiation would be a desired tool for radiogenetic therapy, a combination of radiotherapy and gene therapy. Although various promoters occurring naturally or artificially have been used for researches, one showing higher reactivity to ionizing radiation is desirable. In the present study, we attempted to improve a radiation-responsive promoter of the p21 through a technique called DNA shuffling. A library of DNA fragments was constructed by re-ligation of randomly digested promoter fragments and improved promoters were chosen out of the library. We repeated this process twice to obtain a promoter showing 2.6-fold better reactivity to ionizing radiation compared with its parent, p21 promoter after 10 Gy γ-ray irradiation. Nucleotide sequence analyses revealed that the obtained promoter was densely packed with some of the cis-acting elements including binding sites for p53, NF-κB, NRF-2, AP-1 and NF-Y more than p21 promoter. In addition, it was shown that its induction by ionizing radiation was dependent upon p53 status of a cell line, suggesting that the promoter retained properties of the p21 promoter. This technique is simple and efficient to improve a promoter responsive to other stimulus of interest besides IR.     

Use of commercial grape phenolic extracts to supplement solid foodstuff

Osmotic treatment (OT) has been applied to infuse phenolic compounds into a model food. Two commercial grape extracts were used as a source of phenolics, a grape seed extract (GSE) and a white grape marc extract (WGME). Three different concentrations of total phenolics were applied with and without presence of osmo-active solute (50 g/100 g and 0 g/100 g of sucrose) in the osmotic solution (OS). With a 50 g/100 g sucrose and a total phenolic content in OS ranging from 3 g/L to 15 g/L and operating time up to 8 h, the final total phenolic content in the osmo-treated model food was between 815 mg GAE/kg and 7176 mg GAE/kg. That is between the 0.5 and 1.5 times higher than that of the richest fruits. A soaking process with the same phenolic content but with no sucrose in OS led to a total phenolic content in the model food that was between 80% and 100% higher.Mass transfer of the major phenolics infused into the model food during OT and soaking process was characterized considering the diffusional approach and Peleg's model. Progress of total and individual phenolic content fitted well both models with the exception of the flavan-3-ol dimer concentration.