Free amino acids in botanicals and botanical preparations

ABSTRACT:  Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia , and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and γ-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.     

肉制品中亚硝胺形成机制及植物源提取物对其阻断效果的研究进展

亚硝胺是一类强化学致癌物,肉制品加工过程中可由亚硝化试剂和胺类化合物在弱酸性条件下反应形成。本文综述了加工肉制品中亚硝胺的形成机理、形成影响因素以及其对人体的潜在危害（致癌性和致突变性）,进而从肉制品加工的角度着手,重点探讨了植物源天然提取物（天然果蔬提取物、天然香辛料提取物、中草药提取物）对亚硝酸盐的清除能力以及对亚硝胺形成的阻断作用,为抑制规模化肉制品加工生产中的亚硝胺形成提供理论指导。     

Analysis of distribution systems for supply of synthetic grain protectants to maize smallholder farmers in Zimbabwe: Implications for hermetic grain storage bag distribution

Grain storage in pesticide-free hermetic bags is a promising alternative to synthetic pesticide treatment and storage in polypropylene bags for smallholder farmers but the hermetic bags are not conveniently available to rural customers. Developing a commercial hermetic storage bag distribution chain that supplies bags to smallholder farmers is a challenge for manufacturers. We therefore examined the factors affecting the design of grain synthetic insecticide distribution channels to draw lessons for hermetic bag manufacturers to consider. Key informant interviews with insecticide manufacturers and/or distributors and agricultural merchants along the supply chain from national to grassroots level were complemented with farmer focus group discussions. The insecticide distribution channels were analyzed in terms of channel length and breath. Some of the factors that influenced the length of the insecticide distribution channel included the manufacturer's financial, human and technological resources; the value-to-volume ratio of insecticide products; and the sparse geographic concentration of smallholder farmers. The number of intermediaries in each channel depended on farmer purchase habits, product features and market factors. Given the small operational scale of local insecticide formulators, distribution was mainly through intermediaries. The shorter one-tier supermarket distribution channel primarily served urban consumers while the traditional two-tier wholesaler-retailer channel served rural customers. To penetrate the rural smallholder market segment, the longer channel that placed inventory closer to farmers will continue to be the main route for hermetic bag manufacturers. With a low value-to-volume ratio product feature, collaboration between manufacturers of hermetic bags and rural retailers will be essential. In addition, a large-package delivery approach that aggregates retail orders for a particular farming radius should be considered.     

The Content of Polyphenolic Compounds in Cocoa Beans (Theobroma cacao L.), Depending on Variety,Growing Region,and Processing Operations: A Review

Polyphenols form the largest group of compounds among natural antioxidants, which largely affect the overall antioxidant and antifree radical activity of cocoa beans. The qualitative and quantitative composition of individual fractions of polyphenolic compounds, even within one species, is very diverse and depends on many factors, mainly on the area of cocoa trees cultivation, bean maturity, climatic conditions during growth, and the harvest season and storage time after harvest. Thermal processing of cocoa beans and cocoa derivative products at relatively high temperatures may in addition to favorable physicochemical, microbiological, and organoleptic changes result in a decrease of polyphenols concentration. Technological processing of cocoa beans negatively affects the content of polyphenolic compounds.     

Enniatins fromFusarium avenaceum isolated from balsam fir foliage and their toxicity to spruce budworm larvae,Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae)

Material extracted from hyphae ofFusarium avenaceum, isolated from foliage of balsam fir,Abies balsamea, was toxic to spruce budworm larvae when incorporated into insect diet. The major insecticidal component of the toxic fraction was identified by chemical and spectroscopic methods as enniatin complex, rich in enniatin A/A₁. Possible ecological implications of these observations are considered.     

硫代磷酸酯类杀虫剂──丙溴磷的合成

介绍了杀虫剂丙溴磷及其中间体的合成方法及药效试验。     

毒死蜱及其防治白蚁效果与应用研究进展综述

The present pater talked about the high effect of preventing termite by Chlopyrifos in comparing with some other termiticides. A normal preparing route and some new technologies of pretecting from termite were also discussed.     

Does mercury interact with the inhibitory effect of dichlorvos on Palaemon serratus (Crustacea: Decapoda) cholinesterase?

Mercury is one of the most hazardous metals that may contaminate estuarine ecosystems and induce toxic effects on wildlife organisms. It has been suggested that impairment of cholinesterase (ChE) activity may be involved in the resulting mercury toxicity. Following Palaemon serratus exposure to mercury chloride (HgCl₂), no effect on ChE activity was observed whatever the concentration used (to 37.5 µM) or the time of exposure (to 7 days). By contrast, following 24 h exposure to dichlorvos, an organophosphate insecticide with a well-characterised anti-ChE action, decrease of ChE activity was observed until 30 to 40% basal activity, which seems to be the minimum activity required for prawn survival. In addition, HgCl₂ does not affect dichlorvos toxicity and treatments with a mixture of both compounds can be interpreted as the sum of the two independent toxicities. Therefore, mercury and insecticide toxicities are independent and ChE activity from P. serratus eyes seems to be a reliable and sensitive biomarker for organophosphate insecticides even when organisms are simultaneously exposed to mercury.     

新升本科院校园林专业实践改革的研究

就2000年各高等院校扩招后,新升本科院校园林专业生源质量明显下降、参差不齐且专业实践教学建设跟不上,给教学质量的保证带来了许多新的问题的背景下,提出了新的实践教学改革思路,并通过多年的实践证明,该思路行之有效。     

杀虫剂氯辛硫磷的合成

以邻氯甲苯为原料,经氯化、氰化、成肟和磷酰化反应,制得氯辛硫磷。