Novel Prediction of Total Fat Content in Cocoa Beans by FT-NIR Spectroscopy Based on Effective Spectral Selection Multivariate Regression

Total fat content is a major quality parameter that chocolate manufactures consider when selecting cocoa beans. This paper attempted the feasibility of measuring total fat content in cocoa beans by using Fourier transform near-infrared (FT-NIR) spectroscopy based on a novel systematic study on efficient spectral variables selection multivariate regression. After the efficient spectra interval selection by synergy interval partial least squares (Si-PLS), the data were treated with support vector machine regression (SVMR) leading to synergy interval support vector machine regression (Si-SVMR). Experimental results showed that the model based on the novel Si-SVMR algorithm was superior to the others. The optimum results were assessed by root-mean-square error of prediction (RMSEP) and correlation coefficient (R _pre) in the prediction set. The performance of Si-SVMR model was RMSEP?=?0.015 and R _pre?=?0.9708. This study has demonstrated that the total fat content in cocoa beans could rapidly be predicted by FT-NIR spectroscopy and Si-SVMR technique. The novel strength and accuracy of Si-SVMR in contrast to other multivariate algorithms has been derived.     

近红外光谱法快速检测婴儿配方奶粉中的脂肪酸含量

采用傅里叶近红外光谱结合偏最小二乘法(PLS)法建立了测定婴儿配方奶粉中的总脂肪酸、饱和脂肪酸和不饱和脂肪酸含量的近红外数学模型,并通过交互验证和外部检验两种方式考察了近红外数学模型的可靠性。通过选择不同的波长范围,采用平滑、矢量归一化、一阶求导、二阶求导和散射校正对近红外光谱进行处理,总脂肪酸、饱和脂肪酸和不饱和脂肪酸的校正模型相关系数(R2)分别为0.9337、0.9374、0.9020,RPD分别为3.63、3.65、2.90。结果表明近红外数学模型具有良好的预测性能。采用建立的模型对验证集中的20个婴儿配方奶粉样品进行预测,总脂肪酸含量、饱和脂肪酸和不饱和脂肪酸的预测值与化学测定值之间经配对t检验分析,与常规化学方法得到的检验结果无显著差异。     

红外光谱法测定植物油中反式脂肪酸

研究各种操作条件对红外光谱法测定植物油中反式脂肪酸的影响,得到了较有价值的结论。     

Rapid Determination of Iodine Value and Saponification Value of Fish Oils by Near-Infrared Spectroscopy

ABSTRACT: A rapid method for determining the iodine value (IV) and saponification value (SV) offish oils has been developed using near-infrared (NIR) spectroscopy. The partial least squares (PLS) calibration model was made based on a spectral range between 7560 and 9100 cm⁻¹ due to CH bond. The method was validated by comparing the IV and SV of a series of fish oils predicted by the PLS model to the values obtained by the titration methods of the Japan Oil Chemists' Society. The NIR-predicted IV and SV were completely consistent with chemically determined IV and SV. The NIR method showed higher accuracy and reproducibility than the titration method. It would be suitable for IV and SV determinations offish oils, as well as vegetable oils, and it takes only 2 min per sample.     

Polyunsaturated Fatty Acids and Fat in Fish Flesh for Selecting Species for Health Benefits

An awareness of the protective roll of n-3 polyunsaturated fatty acids against development of cardiovascular disease has prompted the promotion of fish consumption. It is assumed that those fish rich in polyunsaturated fat and particularly those having high ratios of n-3 to n-6 polyunsaturated fatty acids would confer the most benefit. The total fat and fatty acid compositional data are reported herein for 41 different species of fish that are mostly found in the coastal waters of the Eastern United States.     

柱前衍生HPLC法测定鸡脂酶解物中游离脂肪酸含量

建立以2,4-二溴苯乙酮为衍生化试剂,18-冠-6醚为相转移催化剂,同时测定鸡脂酶解物中四种游离脂肪酸的柱前衍生高效液相色谱法.利用Zorbax SB-C18柱(250 mm×4.6mm i.d.,5μm),检测波长254 nm,乙腈和水为流动相进行梯度洗脱,柱温25℃,体积流量1.6 mL/min,外标法定量分析.结果表明:以2,4-二溴苯乙酮为衍生化试剂测定的肉豆蔻酸(15.6～78.1 mg/L)、亚油酸(27.2～136.0 mg/L)、油酸(73.4～367.2 mg/L)和硬脂酸(31.7～158.4 mg/L)在测定范围内呈现良好相关性,相关系数在0.999 3～0.999 8之间.柱前衍生HPLC法简便准确,可用于水解鸡脂中游离脂肪酸含量定量分析.     

欧李果脂肪酸GC-MS检测及其营养分析

为了研究欧李果中脂肪酸,开发其营养价值,采用超声波萃取法对冷冻干燥的欧李果进行分离提取,用GC-MS分析其提取物的化学组成.结果表明,欧李果脂肪酸提取物得率为1.06％,在欧李果中检测到31种脂肪酸.其中,饱和脂肪酸20种,占检出总量37.90％,主要为棕榈酸(9.46％)、木焦油酸(8.02％),硬脂酸(5.97％);不饱和脂肪酸11种,占检出总量51.74％,油酸(20.32％)、亚油酸(15.65％)、亚麻酸(5.22％)3种主要不饱和脂肪酸占检出总量的41.19％,并首次在欧李果中检测到神经酸(1.83％).     

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。     

Determination of Three Alcohols in Chinese Dukang Base Liquor by FT-NIR Spectroscopy

Alcohols are important aroma compounds in Chinese liquors. In this work, 3-methyl-1-butanol, 1-butanol, and 1-propanol in Dukang base liquor were simultaneously analyzed by gas chromatography (GC) and fourier-transform near-infrared (FT-NIR) spectroscopy. The optimal combinations of spectral intervals for three alcohols were selected for modeling. The calibration models, which are based on FT-NIR spectral variables and the chemical values, were established with partial least square (PLS) and validated using internal cross validation. In calibration set, the coefficients of determination (R ²) for 1-propanol, 1-butanol, and 3-methyl-1-butanol were 95.21, 98.05, and 98.05, respectively; corresponding root mean square errors of calibration (RMSEC) were 0.27, 0.49, and 0.67 mg per 100 mL. In validation set, the R ² were 94.72, 97.96, and 95.22; the root mean square errors of prediction (RMSEP) were 0.40, 0.81, and 1.35 mg per 100 mL. The results indicated that the correlation between the values determined by GC and the values estimated by the calibration for the three alcohols was excellent. The FT-NIR spectroscopy calibration models, which with good prediction performance and high precision, could be used as a rapid methods for determination of alcohols in Chinese liquor.     

小米中脂肪酸的GC-MS法测定及营养价值分析

为了研究小米所含有的不饱和脂肪酸及其营养价值,采用超临界萃取法对小米分离提取,用GC-MS分析其化学组成。在小米萃取物中共检测出26种化合物。其中,检测到7种不饱和脂肪酸(64.54%)、7种饱和脂肪酸(22.92%)、7种酯(7.30%)、3种醇(1.95%);新检测出9-十六烯酸、顺式-10-十七烯酸、8,9-亚甲基8-十七烯酸、蓖麻油酸4种不饱和脂肪酸。亚油酸(36.65%)、油酸(26.06%)、棕榈酸(16.33%)、亚油酸乙酯(1.33%)含量较高。     

驴肉脂肪和脂肪酸组成的分析与评价

本文分析驴肉的脂肪含量,并采用气相色谱法对驴肉的脂肪酸成分及含量进行测定.结果表明,驴肉中粗脂肪含量为5.02%,不饱和脂肪酸含量占脂肪酸含量的,55.8%,饱和脂肪酸占44.2%.脂肪酸中棕榈酸C16:0(55.2%)含量最高,其它由高到低依次为油酸(33.0%)、亚油酸(10.1%),棕榈油酸(8.1%)、硬脂酸(6.7%)、肉豆蔻酸(4.1%)、花生四烯酸(2.0%).驴肉中的脂肪酸能较好地满足人体的营养需求.     

基于水平衰减全反射傅里叶变换红外光谱的食品中反式脂肪酸的测定

目的:建立基于水平衰减全反射傅里叶变换红外光谱的食品中反式脂肪酸的快速测定方法.方法:负二阶导数水平衰减全反射傅里叶变换红外光谱法(-2D-HATR-FTIR).使用带有水平衰减全反射(HATR)附件的傅里叶变换红外光谱仪,采集三反油酸甘油酯标样在l 050～900 cm-1波段范围的吸收光谱,并求得负二阶导数谱.根据反式脂肪酸中孤立的反式双键在966 cm-1处的特征吸收与混合标样中反式脂肪酸的含量符合比尔定律的原理,构建定标方程.根据定标方程测定食品样品中反式脂肪酸含量.结果:在试验条件下,定标方程为Y=3 359.2X-0.6175,相关系数0.9997,检出限0.27％,回收率78.06％～112.65％.食品中反式脂肪酸含量最高接近50％.结论:建立一种新的快速测定食品中反式脂肪酸的方法,该法准确可靠,快速、简便,克服了现有红外光谱法灵敏度低的缺点,适用于食品中较低含量反式脂肪酸的快速测定.     

金华火腿中肌间脂肪和皮下脂肪的脂肪酸分析

提取成熟金华火腿中的肌间脂肪和皮下脂肪 ,分离并测定了其中甘油酯、磷脂和游离脂肪酸的含量 ,并对其脂肪酸组成进行了分析 ,结果表明 :肌间脂肪含量为 12. 4 % ,甘油酯、磷脂和游离脂肪酸分别占 77. 3%、11 .2 %和 10 . 9% ;皮下脂肪含量为 90 .7% ,相应的 3部分分别占 88.7%、0 . 2 %和 10 .4 %。肌间脂肪和皮下脂肪的脂肪酸都以C16:0 、C18:1、C18:2 为主要成分。甘油酯里单不饱和脂肪酸的含量都远远高于其在磷脂和游离脂肪酸中的含量 ,而磷脂里多不饱和脂肪酸的含量明显高于其在甘油酯和游离脂肪酸中的含量。     

我国地方猪种肌内脂肪和脂肪酸的研究

综述了我国地方猪种肌肉中脂肪和脂肪酸的研究进展,以期为我国地方猪种开发利用及科研提供一定的经验。     

Determination of Branched-Amino Acid Content in Fermented Cordyceps sinensis Mycelium by Using FT-NIR Spectroscopy Technique

This research investigated the feasibility of Fourier transform near-infrared (FT-NIR) spectral technique in determining branched-amino acid contents (Leucine, Isolecucine, and Valine) in fermented Cordyceps sinensis (C. sinensis) mycelium. A comparison of two variable selection methods, namely competitive adaptive reweighted sampling (CARS) and genetic algorithms, showed that CARS achieved better performance calibrating by partial least square regression or least squares support vector machine methods, with the effective wavelengths mainly concentrated around 12,010–10,050, 7,500–6,000, and 5,000–4,000 cm^?1. For the quantitative determination of Val, Ile, and Leu by the established models, root mean square error of prediction were 0.0662, 0.0594, and 0.0678; correlation coefficients were 0.80, 0.83, and 0.90; residual predictive deviation were 1.66, 1.78, and 2.30, respectively. This study showed that the FT-NIR spectral technique has a potential to determine branched chain amino acids in fermented C. sinensis mycelium and further to facilitate quality control during its production.     

杭白菊中脂肪酸组成的GC-MS分析

以无水乙醚为溶剂,用索氏抽提法提取杭白菊中粗脂肪,进行甲酯化后以正已烷萃取,用GC-MS测定脂肪酸甲酯,分析鉴定出19种脂肪酸,并测定出各脂肪酸的相对含量;不饱和脂肪酸相对含量约占73．4％。     

气相色谱-质谱法测定人造奶油中的脂肪酸

采用氯仿、甲醇混合溶剂萃取人造奶油中的脂肪,并用氢氧化钾-甲醇法甲酯化,通过气相色谱-质谱法分析其脂肪酸成分,鉴定出12种化合物,其中主要以油酸(30.918%)、棕榈酸(53.456%)为主,占人造奶油总脂肪酸量的84.374%,亚油酸的含量已降低至7.817%.     

气质联用技术分析测定啤酒花中脂肪酸

对啤酒花中的脂肪酸类化学成分进行分析测定。采用索氏提取法对啤酒花样品中脂肪酸进行提取,运用气质联用技术结合计算机检索对提取物甲酯化的化学组成及含量进行测定分析。结果表明,啤酒花中主要含有棕榈酸甲酯、亚麻酸甲酯、亚油酸甲酯、油酸甲酯、硬脂酸甲酯等22种脂肪酸;用面积归一化法测定各种脂肪酸相对含量,其中不饱和脂肪酸亚麻酸与亚油酸含量超过70％。     

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。