我国农业综合生产能力研究——基于主成分分析

根据我国实际,构建了农业综合生产能力的评价指标体系;借助于统计分析软件SPSS,用主成分分析法确定各评价指标的权重,客观地评价和分析了我国农业综合生产能力的现状,找出其中存在的问题,并提出相应的对策措施,以促进我国农业综合生产能力的提高.     

沟灌条件下灌水沟入渗特性研究

为探明沟灌时灌水沟的水分入渗规律,从沟灌二维入渗过程、入渗湿润锋运移特性、累计入渗水量变化过程、土壤含水量分布等方面研究了沟灌的入渗特征及其影响,研究表明：灌水沟中水深、沟底宽、湿周对沟灌入渗过程均有明显影响。沟中水深增大,有利于加大侧向入渗,垂向入渗减少,而水深减小,会加大垂向入渗,增加深层渗漏。灌水沟底宽不影响灌水沟的侧向入渗,仅影响垂向入渗,底宽减小,垂向入渗深度相应减小,且土壤表面以下40 cm深以内水平向入渗深度平均值与最大垂向入渗深度的比值在沟底宽小时均大于沟底宽大时。合理的断面形式和大小有利于减小垂向入渗,加大水平侧向入渗,灌水沟断面形式为梯形断面时,宽深比近似为2效果最优。研究结果可为改进沟灌灌水技术提供参考。     

昆明市松华坝水源地水源涵养能力时空变化研究

水源涵养能力是水源地脆弱性诊断的重要指标之一。在对比直线分割、直线斜割和滤波3种基流分割方法的基础上,选取松华坝水源地径流区内4个水文站实测流量资料,用滤波法分割基流,并计算基流量和基流指数。结果显示,左支流冷水河上、下游平均基流指数分别为0.589、0.485,右支流牧羊河上、下游平均基流指数分别为0.528、0.484。此外,1954-1992年冷水河下游地区基流量呈显著减小的趋势,其余区域基流量减小的趋势不显著。水源涵养能力空间上表现为,冷水河流域的水源涵养能力较牧羊河流域强,两流域上游的水源涵养能力均较下游强。     

川西亚高山区域的水源涵养功能变化趋势

[目的]揭示川西亚高山区水源涵养功能的变化趋势,为明确该区的水源涵养动态特征提供科学依据.[方法]以岷江上游的杂谷脑河流域为例,根据杂谷脑河流域出口处的历年降水、气温和水沙资料,应用水量平衡原理,研究该流域水源涵养能力的变化特征.[结果]①研究区径流量呈明显减少趋势,平均每年减少2.83 mm,即水源涵养量平均每年提升...     

Antioxidant and trace element content of damiana (Turnera diffusa Willd) under wild and cultivated conditions in semi-arid zones

Damiana (Turnera diffusa Willd) is traditionally used in the elaboration of tea, liquors, in the production of cosmetic products, and as a medicinal plant. The aim of this study was to evaluate the antioxidant content and trace element concentrations in leaves and stems from damiana grown wild and under cultivated conditions in semi-arid zones. Plants were collected at three different sites, two where damiana grows wild and one where it is cultivated for experimental purposes. Significant differences in the concentration of trace elements, vitamin C and total phenolic compound content, as well as antioxidant enzyme activities, total antioxidant capacity, and lipid peroxidation levels were found between leaves and stems, as well as among sampling sites. Environmental conditions, in combination with genetic factors, apparently affect the trace element concentrations, antioxidant content, and total antioxidant capacity in damiana grown wild. Results suggest that nutrient enrichment, via the addition of fertilizers, contributed to increased antioxidant defenses in the cultivated damiana plants. Furthermore, we suggest that genetic selection, controlled environmental conditions, and specific agrotechnical practices can increase the antioxidant yield in leaves and stems of cultivated damiana.     

广东省菜用桑品种资源嫩芽感官品质和营养功能成分分析

通过对国家桑树种质资源华南分圃内的230个桑树品种资源嫩芽进行感官审评,筛选出口感好、风味佳的菜用桑品种资源8个,对其主要营养物质、风味物质以及桑叶总抗氧化活性进行了测定,并对主要营养和风味物质含量与总抗氧化活性的相关性进行分析.结果表明:桑嫩芽营养和风味物质含量丰富,8个菜用桑品种资源的抗坏血酸含量为20.21～25.10 mg/hg FW、类胡萝卜素含量为4.90～5.91 mg/hgFW、可溶性蛋白含量为0.40％ ～0.53％、可溶性总糖含量为0.92％～1.47％、果糖含量为0.37％ ～0.69％、蔗糖含量为0.22％～0.58％;营养风味物质含量在不同桑树品种资源间存在明显差异,其中菜桑10的抗坏血酸、类胡萝卜素、可溶性糖含量最高,而菜桑04-107的总抗氧化活性最强;各营养物质含量与总抗氧化活性表现出不同程度的正相关,其中仅可溶性蛋白与总抗氧化活性呈显著正相关.     

Optimization of Heat Processing of Farmed Atlantic Cod (Gadus morhua) Muscle with Respect to Cook Loss,Water Holding Capacity,Color, and Texture

Convenience products of fish that are heat processed in-pack are often subjected to a compromise between quality and durability within the framework of required safety. The purpose of this study was to provide knowledge for optimizing pasteurization of cod muscle by quantifying changes in water holding capacity (WHC), cook loss, color, and texture within a wide range of processing times and temperatures. A heat load equivalent to 2 min at 70°C may be applied to the cod while maintaining the WHC above 66%, the cook loss below 5.6%, and keeping hardness and whiteness low, provided that the processing temperature is kept in the range 68 ± 4°C.     

Angiotensin Converting Enzyme and Dipeptidyl Peptidase-IV Inhibitory,and Antioxidant Activities of a Blue Mussel (Mytilus edulis) Meat Protein Extract and Its Hydrolysates

ABSTRACT

Protein extracted from mussel processing coproducts was hydrolyzed with four different food-grade enzyme preparations and assessed for angiotensin converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibitory and oxygen radical antioxidant capacity (ORAC) activities. All hydrolysates tested showed higher activity than the intact protein. ACE and DPP-IV IC₅₀ values in the range 1.13–3.34 and 0.33–2.43 mg mL^?1, respectively, and ORAC values in the range 66.26–121.56 µmol trolox equivalents g^–1 were obtained. These results suggest that some of the mussel meat protein hydrolysates may have potential as functional food ingredients for the management of diseases such as type II diabetes and hypertension.     

Dinoflagellate cysts in ballast sediments: differences between Canada's east coast,west coast and the Great Lakes

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Comparative effects of dietary supplementation with maggot meal and soybean meal in gibel carp (Carassius auratus gibelio) and darkbarbel catfish (Pelteobagrus vachelli): growth performance and antioxidant responses

A 6‐week growth trial was conducted to investigate the effect of dietary supplementation with maggot meal (MGM) and soybean meal (SBM) on the growth performance and antioxidant responses of gibel carp (GC) and darkbarbel catfish (DC). The basal diet was formulated to contain 114 g kg⁻¹ fish meal (FM) and 200 g kg⁻¹ SBM. The basal diet was supplemented with either 280 g kg⁻¹ FM (Control), 390 g kg⁻¹ MGM or 450 g kg⁻¹ SBM to obtain three isonitrogenous (crude protein: 380 g kg⁻¹) and isocaloric (gross energy: 16 kJ g⁻¹) diets. For GC, a significant decrease in specific growth rate (SGR) was only observed in fish fed the SBM diet compared with the control (P < 0.05). Principal components analysis (PCA) of GC showed a higher similarity in antioxidant response to dietary supplementation with MGM and SBM proteins between liver and intestine, but the DC did not. The present results suggest that supplementing 390 g kg⁻¹ MGM protein to basal diet cause an enhancement of the antioxidant capacity in GC, but supplementing 390 g kg⁻¹ MGM and 450 g kg⁻¹ SBM proteins to basal diets resulted in a significant attenuation of the antioxidant capacity in DC.