Nutrient profiles in retail cuts of bison meat

The objectives were to determine the nutrient composition and variation in eight cuts of bison meat in bulls and heifers and identify nutrient relationships in the clod and sirloin by principal component analysis. The nutrients analyzed were: energy, protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, transfat, cholesterol, vitamin A, Ca, Fe, Na and moisture. Differences were observed in fat components between cuts and bulls had higher (P < 0.05) amounts of total, saturated, monounsaturated and polyunsaturated fat in the blade compared to the other cuts. The sirloins had less (P < 0.05) cholesterol than all the other cuts in bulls and the clod in heifers. Fat varied more than protein and moisture in all cuts. Four principal components (PC) accounted for 63.9% of the total variation of the nutrient composition. Total, monounsaturated and saturated fats were in PC1 and cholesterol in PC2 showing that cholesterol is independent of other fats. If dietary alterations elicit changes in bison meat fatty acid profiles, it may be possible to reduce cholesterol independent of total, monounsaturated or saturated fat.     

Growth and lipid accumulation properties of a freshwater microalga, Chlorella ellipsoidea YJ1, in domestic secondary effluents

The combination of microalga-based biodiesel production and wastewater treatment is a promising approach to solve problems related to the energy crisis as well as eutrophication in bodies of water. A freshwater microalga, Chlorella ellipsoidea YJ1, with a high capacity for biomass production and lipid accumulation in secondary effluent was isolated. C. ellipsoidea YJ1 could achieve a biomass of 425 mg L⁻¹ (dry weight) in domestic secondary effluent treated with activated sludge technology; and the lipid content per unit of algal biomass was as high as 43% (w/w) in this condition. The lipid growth rate of C. ellipsoidea YJ1 in domestic secondary effluents could attain 11.4 mg/L. Furthermore, after the cultivation of C. ellipsoidea YJ1, the removal efficiencies of nitrogen and phosphorus from the secondary effluent studied in this paper were more than 99% and 90%, respectively. Logistic and Monod models were used successfully to simulate the growth of C. ellipsoidea YJ1, and its maximum biomass and maximum population growth rate under different initial concentrations of nitrogen and phosphorus could be simulated and predicted using the models. .     

Soil nutrient evaluation from swine effluent application to five forage-system practices

Many contract swine producers are located in the southeastern U.S. In this region almost all of the swine effluent from swine production is applied to warm-season perennial species such as bermudagrass [Cynodon dactylon (L.) Pers.] which is widely grown for summer grazing and hay production. A 3-yr study was conducted to investigate the impact of forage double-cropping on nutrient accumulation and leaching in Mantachie fine loam soil fertilized with swine (Sus scrofa domesticus) lagoon effluent as the source of plant nutrients. Plots of previously established Tifton 44 bermudagrass were overseeded in the fall with one of four winter annuals: berseem clover (Trifolium alexandrinum L.); crimson clover (T. incarnatum L.); ryegrass (Lolium multiflorum L.); or wheat (Triticum aestivum L.). Four plots of bermudagrass were not overseeded and considered as control. Plots were harvested in spring for cool-season annual hay and in summer for bermudagrass hay. Swine effluent was applied during spring and summer on a need base. Suction lysimeters were installed in selected plots at two depths to monitor nutrient leaching. Surface soil samples were taken to determine baseline nutrient contents, followed by three other sampling dates during the study. Bermudagrass dry matter production (3-yr average = 9.8 Mg ha⁻¹) was not adversely affected by the overseeding treatments. Greatest dry matter production was achieved with bermudagrass overseeded with ryegrass (3-yr average  = 11.3 Mg ha⁻¹). Soil pH decreased by almost one unit by the end of the study. While total P (TP) did not change much, Mehlich-3 P (M3-P), K, Cu, and Zn increased significantly, Mg and Mn concentrations decreased by 2002 compared to the baseline levels. Soil P, Mg, K, Fe, Mn, and Zn accumulation were greater under bermudagrass/wheat combination. In general, the influence of double cropping on soil nutrient accumulation was not conclusive, however, this practice provides the year-round green forage for grazing and haying. Nutrient concentrations in soil and lysimeter leachate were directly related to the quantity of effluent applied. Results also demonstrated that effluent application must be coordinated with the nutrient requirements of the growing forages in order to minimize accumulation and leaching.     

Major nutrient balances in small-scale vegetable farming systems in peri-urban areas in China

Balances of major nutrients such as nitrogen (N), phosphorus (P), and potassium (K) in small-scale farming systems are of critical importance to nutrient management and sustainable agricultural development. Mass balances of N, P, and K and some of their influencing factors were studied for two years from July 2003 to July 2005 on small-scale vegetable-farming systems in two contrasting peri-urban areas (Nanjing and Wuxi) of the Yangtze river delta region of China. This balance approach considered organic fertilizer inputs (cow manure, pig manure, and human biosolids), inorganic fertilizer inputs (urea, composite fertilizer, and phosphates), irrigation water, and atmospheric deposition; and considered outputs by vegetables. Input via organic fertilizers was significant for all element balances in the Nanjing area. Inorganic and organic fertilizer, particularly inorganic fertilizer, contributed major nutrient inputs to the system in the Wuxi area. Compared with nutrient output by vegetables, there were significant surpluses of N and P on two vegetable farm systems. Furthermore, N surplus in the Nanjing area was higher than that in the Wuxi area with an inverse relationship to P surplus. In contrast, the general trend of K balances was negative on both sites; hence, the nutrient use efficiency was significantly lower for N and P than K. The nutrient imbalance may be attributed to the differences between fertilizer types and management modes driven by social economic status differences among farmer households. The large N and P net excess creates an environmental threat because of potential losses to ground or surface waters, whereas negative K balance creates soil fertility risks. The results highlight researchers’ and farmers’ need to develop rational fertilization technology to optimize nutrient management on vegetable farmlands to promote sustainable agricultural development in peri-urban areas.     

Red meat in global nutrition

The influence of data and recommendations from developed countries on nutrition guidance has overshadowed recognition of the key micronutrients and protein contributed by red meat to the global food supply. Relative to the energy it contributes, the impact of red meat on the nutritional quality of the human diet via its contribution of protein and key micronutrients is under-appreciated. The current discussion will review red meat nutrient composition and global consumption rates and discuss the evidence underpinning current dietary recommendations. The beneficial role of red meat in reducing risk factors associated with noncommunicable disease in developed countries and improving the nutritional status of developing nations will also be reviewed.     

The evolution of lean beef: identifying lean beef in today's U.S. marketplace

Changes in cattle breeding and management coupled with extensive trimming of visible fat from retail cuts have resulted in the wide-spread availability of lean beef to U.S. consumers. Despite these changes, there is limited awareness regarding the reduced total fat content and the favorable fatty acid profile of beef. Relative to the calories it contributes, the impact of beef on the nutritional quality of the American diet via its contribution of protein and certain key micronutrients is often under appreciated. The following discussion documents the progressive reduction in fat content of U.S. beef during the past 30 years, highlights ongoing efforts to update United States Department of Agriculture nutrient data for beef, and summarizes findings from randomized controlled trials of beef and plasma lipid outcomes. Beef is a popular, nutrient-dense food and the availability of at least 29 lean cuts of beef in the U.S. marketplace can help consumers meet their cardiovascular health goals.     

基于近红外光谱技术的鲢鱼营养成分的快速分析

目的通过采集鲢鱼的近红外光谱数据和测定鱼肉营养成分含量探索鲢鱼营养成分的快速分析方法。方法采集254个鲢鱼鱼肉样品的近红外光谱数据,经过多元散射校正、正交信号校正、数据标准化等20种方法预处理,在1000~1799 nm光谱范围内,结合化学实测值分别采用偏最小二乘法、主成分分析和BP人工神经网络技术、偏最小二乘法和BP人工神经网络技术建立鲢鱼营养成分近红外定量模型。结果鲢鱼鱼肉粗蛋白含量为12.05%~19.05%,粗脂肪含量为0.24%~5.27%,水分含量为72.62%~80.58%,灰分含量为0.46%~1.50%,数据范围较大,可满足建模要求。在3种建模方法中,近红外光谱数据结合偏最小二乘法建立的鲢鱼营养成分模型最优,所得的粗蛋白、粗脂肪、水分和灰分的近红外定量模型的相关系数分别为0.9969、0.9925、0.9831和0.9976。结论采用近红外光谱数据和偏最小二乘法建立的模型具有较好的预测能力,能较为准确、快速地分析出鲢鱼鱼肉粗蛋白、粗脂肪、水分和灰分的含量。     

莲子的营养保健功能及开发利用

介绍了莲子的营养价值、保健功能以及几种莲子产品的加工技术。     

生长发育过程中晒黄烟的养分吸收和干物质积累

通过田间试验研究了晒黄烟生长发育过程中干物质和养分积累与分配规律。结果表明,晒黄烟在整个生长发育过程中,干物质积累和养分吸收呈“慢-快-慢”的变化趋势,干物质积累的高峰期在移栽后30～75d,大量元素和微量元素的积累高峰期分别出现在移栽后的30～60d和45～75d。晒黄烟对大量元素的吸收量表现为N>K>Ca>P>Mg,对微量元素的吸收量表现为Mn>Fe>Cu>Zn>B>Mo。干物质及养分在各器官中的分配比例均表现为叶>茎>根。     

田间状况下烤烟养分吸收动力学及其在平衡施肥中的应用

在土壤气候条件不同的南方湖南酸性红壤地区和北方河南石灰性土壤地区进行的田间试验表明：在烤烟移栽后的前３周中，烤烟烟株吸收的Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ的速率极低，从第４周开始，烟株吸收Ｎ、Ｋ和Ｃａ的速率增加极快，并在第６至８周达到最大吸收速率，然后急剧下降。直到收获结束，Ｐ和Ｍｇ的吸收速率都增加极少。烤烟干物质累积速率在曲线形状上与养分吸收速率曲线相似，但二者不同步，干物质最大累积速率比养分最大吸收速率迟了约半周至１周。说明烤烟必须为其快速生长首先积累必需的养分。在烤烟移栽后的前６周，烟叶内的Ｋ／Ｎ比变化缓慢，从６周开始急剧增加并达到最大值。据此，建议在基肥中使用较高的Ｋ／Ｎ比，而在窝肥中使用较低的Ｋ／Ｎ比。河南襄县点的Ｋ／Ｎ比明显小于湖南慈利点，说明在襄县点应增加钾肥的施用，以提高烟叶中的Ｋ／Ｎ比。在慈利点，烤烟早期吸收的钾多于钙，晚期吸收的钾少于钙。然而在襄县点，烟株整个生育期吸收的钙均大于钾。烟叶早期的含钾量最高，随着生育期的发展而逐渐降低。慈利点烟叶钙含量随着生育期的发展稍微有所下降，而襄县点的烟叶钙含量却随着生育期的推移明显增加。