阳澄湖大闸蟹的经济与文化价值探析

享誉海内外的阳澄湖大闸蟹是江苏省苏州地区的著名特产,其味道鲜美,营养丰富,自古就受到广大食客的青睐,形成了独特的食蟹文化.今日阳澄湖大闸蟹带来了可观的经济效益和社会效益,对地方经济发展起到了一定的推动作用.     

速冻草莓的营养品质变化趋势

草莓果实在速冻加工及速冻后冷藏阶段,主要营养成分维生素C、糖、酸等的含量发生有规律的变化。速冻过程中有机酸含量迅速增加,还原糖和维生素C含量则迅速降低。在冷藏过程中有机酸含量逐渐升高,还原糖和维生素C含量逐渐降低。     

小麦面粉营养成分与出粉率之间的关系

本文对小麦面粉营养成分与出粉率之间的关系进行了阐述;给出了国外发达国家的面粉营养强化标准.     

食品营养标签分析的标准物质研究

提高测量精确性可以保证食品营养标签提供食品营养可靠可知性和产品质量,是提高食品营养质量评价的重要手段。食品营养成分标准物质可保证测量有效性,是验证营养标签分析方法和实验室内分析的质量保证所必需的,对营养标签标准和标签法具有支持和推动作用。阐述了我国和美国食品营养分析标准物质,并介绍了美国AOAC作为发展一系列基于蛋白质、脂肪和碳水化合物的代表所有食品标签分析的标准物质的食品三角形模式图。     

近红外反射光谱分析在土壤肥料学的应用及发展方向

近红外反射光谱分析是一种"巨人"分析法,在土壤肥料及植物营养科学具有广阔的应用前景。对近红外反射光谱分析在土壤肥料及植物营养学科中的应用,存在问题,及其在土壤肥料及植物营养学科领域的发展方向进行了评述。     

玉米专用高分子缓释肥的制备及肥效研究

以自制的脲甲醛低聚物和磷酸二氢钾．磷酸混合液反应合成了一种多营养元素高分子缓释化肥．通过控制投料比使其N：P2O5；K2O=10：7．6：1．5，符合玉米生长对N，P，K的需要．大田试验结果表明，单独施用高分子化肥的增产率为16．56％，高分子化肥与农家肥混合施用的增产率为56．51％，明显高于常规施肥的SV玉米专用肥和农家肥混用时的增产率49．11％．     

水产养殖动物营养与饲料工程发展战略研究

本文综述了我国水产养殖动物营养学研究和饲料工程方面近期的研究,分析了产业发展的问题,探讨了下一步的政策措施。可以发现,过去10多年里,水产动物营养与饲料的发展在营养素需求、动物的摄食与投喂、仔稚鱼饲料、亲本营养、添加剂等方面取得了重要的进展,但仍然存在饵料系数高、环境排放大、饲料成本高、效益不稳定等问题。下一步的研究应该以"安全高效,节约环保"为目标,引入生态学和现代组学理念,开展水产动物营养代谢的分子机理、动物的营养需要与精准饲料配方技术、饲料质量控制与加工工艺、精准投喂技术、品质调控技术等方面的研究,同时在政策上应该扩大学科交流、实行长期稳定支持等。     

Nutritive Substitution of Zinc by Cadmium and Cobalt in Phytoplankton Isolated from the Lower Great Lakes

Low ambient concentrations of trace metals including Zn may limit phytoplankton productivity in the North American Great Lakes. The microalgae Chlorella sp. UTCC 522 (Chlorophyta) and Cyclotella sp. UTCC 520 (Heterokontophyta), indigenous to the Great Lakes, were assayed for their Zn requirement and the ability for Co and Cd to metabolically substitute for Zn under conditions in which Zn bioavailability was limiting cell growth. Bioassays were conducted in the laboratory using chemically defined media and the metal buffer EDTA to control the free-ion concentrations of Zn²⁺ (10^−15.3−10⁻¹⁰ mol/L), Cd²⁺ (10^−15.1−10⁻¹⁰ mol/L), and Co²⁺ (10⁻¹⁴−10⁻¹⁰ mol/L). Influence of the metals on the phytoplankton was measured by the effect on specific growth rate. Both microalgae required Zn and could use Co and Cd as Zn substitutes; Cd was used less-effectively, although to a greater extent by the diatom Cyclotella than by the chlorophyte, Chlorella. The observed ability of the phytoplankton to use Cd and Co as Zn substitutes suggests that microalgae play an important role in the geochemical cycling of Zn, Cd and Co in large lakes, and the mobilization of Cd in lake ecosystems impacted by pollution.     

Effects of nitrogen source,rate and application time on boronia (Boronia megastigma Nees) leaf nitrogen and flower production

Nitrogen was supplied from two fast release sources, ammonium sulfate ((NH₄)₂SO₄) and calcium nitrate (Ca(NO₃)₂) and a slow release source, isobutylidene diurea (IBDU) to boronia, a new flower crop native to Australia. At lower rates (25 kg per ha), N availability from different sources, as indicated by the leaf N concentration, did not differ within a month after application but three months after application, N availability was higher from IBDU than from (NH₄)₂SO₄ or Ca(NO₃)₂. At 50 or 100 kg per ha, N availability was higher throughout the year from (NH₄)₂SO₄ or Ca(NO₃)₂ than from IBDU, thereby allowing luxury consumption and causing toxicity. The flower yield increased with increasing N rates. Complete doses of all N rates which were applied early during the vegetative growth gave the highest yields and the same N rates applied in split doses at different phases of plant growth decreased the yields. In addition, high N availability during flowering (caused by a split dose) further decreased the yield. At all application times, IBDU gave the highest yield and the differences in yields with (NH₄)₂SO₄ and Ca(NO₃)₂ were not significant. The leaf N concentration associated with maximum yield declined as the plant advanced towards flowering.