NIR光谱法测定烟草中棕榈酸、亚麻酸及亚油酸

为了快速检测烟草样品中的棕榈酸、亚麻酸及亚油酸含量,采用偏最小二乘法(PLS)将242个烤烟样品的近红外光谱(NIR)及其棕榈酸、亚麻酸、亚油酸含量GC测定值进行拟合,建立了校正模型,考察了光谱预处理方法和光谱谱区范围对模型的影响,并进行了内部交叉验证和模型精度检验及30个测试样品的外部验证。结果表明:①多元散射校正法和7502~5442.3,4427.9~4246.7 cm-1,一阶导数法和7502~5442.3,4601.5~4246.7 cm-1,矢量归一化法和8724.7~5438.5,4427.9~4246.7 cm-1谱区范围分别适合棕榈酸、亚麻酸、亚油酸模型;②3个模型的平均相对精度分别为98.41%,97.84%,98.84%;③3个模型的预测标准偏差均小于5%,且NIR预测值与GC测定值不存在显著性差异。NIR光谱法适合批量烟叶样品中棕榈酸、亚麻酸及亚油酸含量的快速分析。     

Oil Content and Fatty Acids Composition in Brassica Species

Seeds of 20 accessions of six Brassica species including cultivated and five wild relatives were analyzed for oil and fatty acid composition. The results showed that oil content varied from 21 (B. nigra) to 46% (B. napus). Among wild species, B. rapa and B. oleracea had highest oil content (31 and 28%, respectively). The main fatty acids of oleic, linoleic, linolenic, erucic, palmitic, and stearic acids accounted for 89–94% of the total fatty acids in all species. Cultivated species of B. napus had highest oleic acid (61%) and lowest erucic acid (1%) content compared to other studied species. Brassica rapa and B. oleracea had the highest content of erucic acid (41 and 46%, respectively). The highest content of linolenic (20%) and linoleic (19%) acid was observed for B. juncea. The results showed that there was high genetic variation among the studied species for oil content and fatty acids composition. This indicates that seed oil of these species is possibly suitable for both human consumption and industrial purposes.     

油脂氢化过程中反式脂肪酸形成及降低措施

该文对油脂氢化过程中反式脂肪酸形成及降低反式脂肪酸含量措施进行论述。通过控制氢化操作条件,选择贵金属催化剂,加入添加剂,选择超临界流体氢化和电化学氢化反应器等均能减少油脂氢化过程中反式脂肪酸形成。     

气相色谱法测定常见植物油中脂肪酸

随着营养学研究发展,人们对脂肪酸认识不断增加。中国营养学会也推荐膳食中必需脂肪酸摄入理想比值,市场上也出现大量调和油,为了评估食用植物油营养价值,该研究分析常用食用植物油中脂肪酸组成和各种油营养特色。方法:用氢氧化钾-甲醇溶液将植物油皂化后,在三氟化硼作为催化剂作用下,用甲醇将样品甲酯化,正己烷提取甲酯化产物。以毛细管柱DB-23作为分离柱,用气相色谱法测定植物油脂肪酸组成。结果:大豆油,葵花籽油,玉米油中含有50％-60％亚油酸和20％-30％油酸,营养均衡合理;花生油,芝麻油中油酸、亚油酸含量约35％-45％,易于人体吸收;菜籽油中含有45％油酸和15％芥酸,芥酸对人体健康有不利作用;橄榄油,茶籽油中含有75％-80％油酸,红花籽油中含有约80％亚油酸,有降低胆固醇功效。     

进口棕榈油产品脂肪酸成分分析和比较

对进口棕榈油产品中脂肪酸成分进行分析,比较不同产品脂肪酸成分不同,从而可辨别它们不同特性,为在实际工作中鉴别提供理论依据。     

Determination of True Ileal Amino Acid Digestibility in Feedstuffs for Pigs with the Linear Relationships between Distal Ileal Outputs and Dietary Inputs of Amino Acids

This study was carried out to investigate the methodological aspects of extrapolating the ileal losses of endogenous amino acids (AA) with linear relationships between the distal ileal outputs and dietary inputs of AA. Six barrows, average initial body weight 35 kg, were fitted with a simple T-cannula at the distal ileum and fed six diets according to a 6×6 Latin square design. Six maize starch-based diets containing six levels of crude protein (CP) and AA from soya bean meal (4, 8, 12, 16, 20 and 24% CP, respectively) were formulated. Chromic oxide (4 g kg^-1 diet) was included as the digestibility marker. Each experimental period consisted of 8 days. Ileal digesta were collected, at 2 h intervals, for a total of 24 h during days 7 and 8. There were strong linear relationships (P<0·01) between the ileal outputs and dietary inputs of AA. Differences in ranges of graded dietary levels of AA affected the linearity and caused large differences in the extrapolated levels of ileal endogenous AA. Therefore, the design of a suitable range of graded dietary levels of AA is the most important methodological consideration for the determination of endogenous AA losses and the true ileal digestibility values of AA with the linear relationship. For CP and the essential AA, the true ileal digestibility values (%) in soya bean meal and the ileal endogenous losses (g kg^-1 dry matter intake, in parentheses) were as follows: CP, 89·4 (16·4); arginine, 96·1 (0·68); histidine, 92·4 (0·24); isoleucine, 91·7 (0·45); leucine, 90·7 (0·69); lysine, 90·5 (0·48); methionine, 93·6 (0·13); phenyl-alanine, 92·5 (0·38); threonine, 86·5 (0·71) and valine, 90·3 (0·56). Furthermore, the levels of endogenous AA extrapolated with the linear relationships between the ileal outputs and dietary inputs of AA were very close to the values estimated with the linear relationships between the dietary contents of apparent ileal digestible and total AA, suggesting that both models of linear relationships can be used as the regression analysis technique for determination of ileal losses of endogenous AA and true ileal digestibility values of AA in feedstuffs for pigs. © 1997 SCI.     

食用植物油脂肪酸的高分辨气相色谱分析

提出用一种经过改进的方法制备食用植物油的脂肪酸甲酯衍生物，并利用高分辨率毛细管柱分析其中脂肪酸的组成和含量。在确定的气相色谱操作条件下，所用的毛细管柱不仅能够测定食用植物油中的主要成分，而且可测得花生油中含量低至10mg／L数量级的痕量芥酸成分。     

Extraction and physicochemical properties of soya bean protein and oil by a new reverse micelle system compared with other extraction methods

Reverse micelle extraction is a novel technology for the separation of plant components such as proteins and oil. In this study, sodium bis(2‐ethylhexyl) sulphosuccinate (AOT) reverse micelle system and AOT/Tween 85 reverse micelle system were used to extract soya bean protein and oil from soya bean flour. The physicochemical properties of the protein and oil extracted were investigated and compared with traditional extraction methods. The results showed that the efficiency of forward extraction of soya bean protein using an AOT/Tween 85 reverse micelle system was superior to that using an AOT reverse micelle system at the optimal extraction conditions. In addition, soya bean proteins extracted using reverse micelle extraction had no unordered structure under Fourier transform infrared spectroscopy. The acid and peroxide values of oil products from two reverse micelle extractions were lower than that from immersion. The results indicated that AOT/Tween 85 reverse micelle system is effective in extracting soya bean protein and oil.     

巧克力样品中反式脂肪酸含量的测定

采用气相色谱内标法,对20个巧克力样品中的反式脂肪酸含量进行测定分析。试验结果表明,以代可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至4．96％之间。以可可脂为主要原料的巧克力样品中,反式脂肪酸含量范围在未检出至0．844％之间。所测定的巧克力样品中反式脂肪酸以反十八碳一烯酸为主。     

高效液相色谱-蒸发光散射法测定烟草中的高级脂肪酸

研究了以3 mol/L氢氧化钾-乙醇溶液作皂化剂,高效液相色谱-蒸发光散射法同时测定烟草中5种高级脂肪酸的方法.结果表明:亚麻酸、亚油酸、棕榈酸、油酸和硬脂酸的回收率为96.5%～102.3%,相对标准偏差分别为1.53%,2.85%,2.09%,2.35%,1.92%.该方法适合烟草中这5种高级脂肪酸的同时检测.     

富含花生四烯酸的微生物油脂的室内精炼及其成分测定

花生四烯酸（AA）是人体必需脂肪酸,具有极高的保健价值。对经过发酵、浸提得到的富含AA的微生物油脂进行脱胶、碱炼、脱色、脱臭等精炼处理。采用气质联用分析油脂中脂肪酸的成分及含量。     

两种不同南瓜籽油中脂肪酸的GC/MS分析

采用超声波提取辽宁产普通南瓜籽和黑籽南瓜籽油，用氢氧化钾－甲醇法酯化后，对其进行GC／MS分析，从普通南瓜籽油中检测出8种脂肪酸，黑籽南瓜籽油中检测出15种脂肪酸，其中人体必需的不饱和脂肪酸含量较高。     

HPLC测定海豹油软胶囊中3种多不饱和脂肪酸含量

目的建立测定海豹油软胶囊中有效成分二十碳五烯酸(EPA)、二十二碳六烯酸(DHA)、二十二碳五烯酸(DPA)含量的方法。方法以氰基柱色谱柱为分析柱,乙腈-水(90∶10)为流动相,检测波长220 nm。结果 EPA甲酯、DHA甲酯和DPA甲酯线性范围分别为0.6～3.6μg,0.6～3.6μg,0.3～1.8μg,加样回收率分别为99.75%,100.37%,100.35%,RSD分别为1.19%,0.87%,1.22%。结论本方法简便、快速、稳定、重复性好,可用于海豹油软胶囊的质量控制。     

Modification of Fatty Acids in Milk by Feeding Calcium-Protected High Oleic Sunflower Oil

Calcium soaps of high oleic sunflower oil (HOS-Ca) were prepared, using alkaline hydrolysis and calcium precipitation, and freeze-dried. Cows’ diets were prepared to provide 0, 0.85 kg or 1.7 kg HOS-Ca/day. Fatty acids and cholesterol were determined by gas chromatography. Sensory evaluations of milk from cows fed 0 and 1.7 kg HOS-Ca/day were conducted using triangle tests. The 18:lco9 concentration in milk from cows fed the 1.7 kg HOS-Ca diet increased from 22.9 to 35.2% compared to the control (p<0.05). Concentration of total medium-chain saturates (C12-C16) decreased from 40.7 to 31.4% (p<0.05). Feeding HOS-Ca resulted in increases of monoene fatty acids and lower medium-chain saturated fatty acids but no change in milk flavor.     

胰脂肪酶法测定食用油甘油三酯中脂肪酸的位置分布

本实验采用sn-1,3位专一性脂肪酶(胰脂肪酶)对甘油三酯进行作用,专一水解位于sn-1、sn-3的酯键,将该两个位置上的脂肪酸游离出来,通过薄层层析分离得到游离脂肪酸和sn-2-甘油一酯,甲酯化作用后用气相色谱法对脂肪酸进行测定。用该方法对花生油、大豆油、玉米油、菜籽油、茶油进行了测定。结果表明,这几种油不饱和脂肪酸含量达到了80%,在sn-2位上分布更是超过了90%,而少量的饱和脂肪酸则主要是分布在sn-1,3位上。     

毛细管气相色谱内标法测定沙棘油中的脂肪酸

建立了以十七烷酸甲酯为内标物,用毛细管气相色谱同时测定沙棘油中六种脂肪酸（棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸、亚麻酸）的方法。样品经氢氧化钾-甲醇皂化、三氟化硼-甲醇酯化后使生成相应的脂肪酸甲酯,以DM—FFAP毛细管柱分离,火焰离子化检测器测定。用保留时间定性,内标法定量。结果表明,在所选择的色谱条件下,上述脂肪酸在10min内获得较好的分离;六种脂肪酸的峰面积与其质量浓度有良好的线性关系,相关系数均大于0．9998;样品加标回收率（n=6）为92．1％～101．4％;相对标准偏差为2．37％～4．19％;最低检出限为4．0mg／L。该方法操作简便、快速、准确,适合批量样品的测定。     

加工零/低反式脂肪酸人造塑性油脂技术

研究显示膳食中过高的反式脂肪酸会增加血液中低密度脂蛋白胆固醇与总胆固醇的含量,引起各种慢性疾病,特别是心血管疾病,严重危害人体健康。膳食中的反式脂肪酸主要来自氢化油脂。为消除或减少食品中的反式脂肪酸,通过工艺的改进,特别是改进氢化技术以及使用酯交换技术,是目前的主要方法。本文总结了加工零/低反式脂肪酸人造塑性油脂技术的研究进展情况,以期为业界提供参考。     

混合溶剂法测定稻谷脂肪酸值的研究

对混合溶剂法测定稻谷脂肪酸值进行了研究。用石油醚和无水乙醇的混合溶剂代替无水乙醇,滴定终点判断清晰;用差异性检验分析比较两种方法的测定结果,差异不显著。通过样品比对实验,极差小于重复性临界极差．测定结果可比性好。     

Variation in protein and trypsin inhibitor activity with maturity and amino acid composition of winged bean (Psophocarpus tetragonolobus) seeds

The protein and trypsin inhibitor activity in pods and seeds of winged bean (Psophocarpus tetragonolobus (L) DC) increase, and in the pod hull decrease, with the maturity of plant. The seeds of 21 cultivars both exotic and of Indian origin cultivated on marginal alkaline soil (pH 8.7) were analysed for protein (36.4–45.3) and amino acid composition (lysine 4.8 to 6.7).     

HPLC法同时测定红油豆瓣酱中的7种非食用色素

建立了红油豆瓣酱中碱性嫩黄O、碱性橙Ⅱ、罗丹明B和苏丹红Ⅰ、Ⅱ、Ⅲ、Ⅳ同时测定的高效液相色谱法.样品用乙腈/水(7:3,V/V)超声提取后冷冻离心去油,以甲醇和乙酸铵缓冲溶液为流动相进行梯度洗脱,检测波长为435 nm、510nm和547 nm.上述7种色素组分在其质量浓度为0.1～10 μg/mL时有良好的线性关系,...