近红外光谱测定不同鲜肉肉糜中蛋白质含量

采集4 000~10 000cm~(-1)波数范围内210份鲜肉(牛、羊、猪肉各70份)为校正集样品光谱数据,在不同的光谱预处理基础上,用偏最小二乘法(partial least squares,PLS)建立了单独的不同种类肉品,及其混合鲜肉肉糜红外光谱与蛋白质测量值之间的定量分析模型。90份鲜肉(牛、羊、猪肉各30份)为预测集样品,采集光谱数据后用于模型的验证。结果表明:鲜肉建模集及预测集相关系数分别为0.954,0.929;RMSEC及RMSEP分别为0.495,0.669。该模型能够很好地实现鲜肉蛋白质含量的快速测定,提高了模型预测的广适性。     

Discrimination of adult steers (oxen) and young cattle ground meat samples by near infrared reflectance spectroscopy (NIRS)

Near infrared reflectance spectroscopy (NIRS) was used to discriminate different types of ground beef samples. Fifty-three and sixty-seven samples of longissimus thoracis muscle corresponding to adult castrated steers (over 4 years old) and young cattle (under 14 months old), respectively, were homogenized and scanned over the NIR range (1100-2500nm). The results showed that NIRS could successfully discriminate 100% of ground beef samples depending on the sort of animal, probably as a consequence of differences in the intramuscular fat and water contents. Thus, NIRS is a fast, inexpensive, and non-destructive method that can be used to discriminate these beef products.     

大豆中异黄酮含量的测定及其近红外分析

以100份中国核心大豆种质资源为材料,建立高效液相色谱法(HPLC)测定大豆中异黄酮5组分和总异黄酮。扫描大豆的近红外光谱,以傅里叶近红外光谱法(FT-NIRS)与HPLC技术相结合,采用偏最小二乘(PLS)回归和交叉验证法,探讨利用FT-NIRS技术预测异黄酮含量的可行性。总异黄酮近红外预测模型的内部交叉验证其校正决定系数(R2)和交叉检验均方误差(RMSECV)分别为0.8763和0.515,外部验证其校正决定系数(R2)和预测均方误差(RMSEP)则分别是0.9492和0.599。结果表明,利用FT-NIRS预测大豆中总异黄酮含量是可行的,但是各异黄酮组分的近红外模型不能达到准确预测要求。大豆异黄酮近红外模型的建立对今后大豆的异黄酮选育工作可以提供帮助。     

Prediction of lamb meat fatty acid composition using near-infrared reflectance spectroscopy (NIRS)

The aim of this study was to assess the feasibility of near-infrared reflectance spectroscopy (NIRS) for predicting lamb meat fatty acid composition. We compared ground vs. intact non-ground meat samples to determine whether grinding and homogenisation of meat samples improved the performance of the predictions. We used 76 male lambs, of which 32 were pasture-fed and 44 stall-fed with concentrate and hay. The reflectance spectrum of Longissimus lumborum muscle was measured at wavelengths between 400 and 2500 nm. Predictions were better with ground than with intact muscle samples. NIRS accurately predicts several individual fatty acids (FA) (16:0, 18:0, 16:1 Δ9 cis, 17:1 Δ9 cis, 18:1 Δ9 cis, 18:1 Δ11 cis and 16:1 Δ9 trans) and several FA groups (total linear saturated FA, total branched saturated FA, total saturated FA, total cis monounsaturated FA (MUFA), total trans MUFA, total MUFA and total polyunsaturated PUFA). These results show the potential of NIRS as a rapid, and convenient tool to predict the major FA in lamb meat.     

基于近红外透射光谱的大豆蛋白质和粗脂肪含量快速检测

该研究采用近红外光谱分析技术分别建立大豆蛋白质和粗脂肪含量的近红外检测模型,比较了不同数学处理方法和去散射校正方法及不同回归技术对模型准确性的影响,选出最佳的近红外检测模型,并通过内部验证和外部验证对模型的预测能力进行评价。结果表明:所建立的大豆蛋白质和粗脂肪含量的近红外检测模型的内部验证相关系数分别为0.947 1、0.889 0,外部验证相关系数分别为0.962 2、0.915 5。说明所建立的大豆蛋白质和粗脂肪含量的近红外检测模型具有很好的预测能力,近红外光谱技术可用于大豆成分含量的快速检测。     

Influence of intramuscular fat content on lipid composition,sensory qualities and consumer acceptability of cured cooked ham

The present study is part of a project which aims to examine the influence of intramuscular fat (IMF) content on the sensory attributes and consumer acceptability of pork. An experiment was conducted to evaluate the influence of IMF level in muscle semimembranosus (SM) on the composition of its lipid fraction and on the sensory qualities and consumer acceptability of cured cooked hams. Thirty‐two carcasses were selected 24 h after slaughter from 125 Duroc × Landrace castrated male pigs showing large variability in SM muscle IMF content and were assigned to four IMF groups: ≤2%, 2–3%, 3–4% and >4%. Cured cooked ham slices were evaluated by a trained expert panel of 12 members and by a group of 56 consumers. Results from lipid analyses indicate that (i) an increase in IMF content was almost entirely reflected by an increase in the triglyceride content of the muscle and (ii) higher IMF levels were associated with higher free fatty acid and monoglyceride and lower cholesterol levels. The sensory evaluation of marbling significantly increased with IMF level, whereas other sensory qualities were unaffected. High IMF levels significantly depreciated the consumer perception of fat, aspect, taste and smell of ham slices. Overall, slices with the highest IMF levels got the least favourable rating by consumers. The present study indicates that increased IMF levels in muscle semimembranosus do not have significant effects on the sensory attributes of cured cooked hams, apart from the perception of marbling. However, high IMF levels have detrimental effects on the acceptability by consumers. © 2000 Society of Chemical Industry     

Applications of miniaturized and portable near infrared spectroscopy (NIRS) for inspection and control of meat and meat products

In this review, the principles and usage of NIRS are described, emphasizing the importance of portable NIRS as a rapid analysis system in the meat industry. The miniaturized and portable NIRS instruments offer a great potential for on-site monitoring quality control not only in the meat sector but also all other food and agro-industries. The mobility of these devices, enabling in situ, robust, on-site, and product-to-product on-line inspection and control, are their major advantages. The emergence of miniature and portable NIRS systems allows establishment of rapid protocols, which might increase rigorous quality control, implying that food quality can be routinely monitored along the entire logistic chain. For meat-value chain, the possibility to implement portable NIRS systems at any point along the logistic chain could dramatically reduce the number of serious scandals related to meat quality and safety. Conversely, results obtained with these instruments are unrealistic in some applications, stressing the need for more applications with diversity in sample presentation and measurement techniques. This will lead to improvements in their performance and help to establish more robust models. In the near future, these devices might stand as promising alternatives to large, expensive, and benchtop types in food analysis, inspection, and control.     

Ability of near infrared reflectance spectroscopy (NIRS) to estimate physical parameters of adult steers (oxen) and young cattle meat samples

The potential of NIRS-based models to predict several physical parameters of oxen and young cattle beef protected by a quality mark was evaluated. Fifty-three and 67 samples of Longissimus thoracis muscle corresponding to oxen and young cattle reared in extensive conditions were analyzed for pH, colour (L^∗, a^∗, b^∗), water holding capacity (WHC) and Warner–Braztler shear force (WBSF), according to the conventional methods. Several factors which might have jeopardized the prediction of pH, a^∗, WHC and WBSF by NIRS are considered in the discussion section. However, the best NIR calibrations, tested by full cross-validation, were for L^∗ (R² = 0.869; SE_CV = 1.56) and b^∗ (R² = 0.901; SE_CV = 1.08) colour parameters in meat samples from young cattle. It can be concluded that NIRS could be a useful tool for estimating the colour of young cattle meat samples, primary consideration for consumers when making purchasing decisions.     

Determination of the protein content in brine from salted herring using near-infrared spectroscopy

Near-infrared reflectance (NIR) spectroscopy in the spectral range of 1000-2500 nm, was measured directly on brine from barrel salted herring, to investigate the potential of NIR as a fast method to determine the protein content. A principal component analysis performed on the NIR spectra shows two groups, separating the first 100 days of storage from the storage time exceeding 100 days. A partial least-squares regression model between selected regions of the NIR spectra and the protein content yields a correlation coefficient of 0.93 and a prediction error (RMSECV) of 0.25 g/100 g. The results clearly indicate that NIR spectroscopy has a potential as a fast and noninvasive method for assessing the protein content in brine from barrel salted herring, which again may be used as an indicator for the ripening quality of barrel salted herring.     

Chemical and discriminant analysis of bovine meat by near infrared reflectance spectroscopy (NIRS)

Near infrared reflectance spectroscopy (NIRS) was evaluated as a tool to segregate different types of bovine meat and predict several chemical fractions on samples from two breeds, three muscles and six grading (Chilean system) categories. Samples previously minced, frozen and thawed, were scanned (400–2500 nm) and then analyzed for dry matter, crude protein, ether extract, total ash and collagen content, after freeze drying. Discriminant analysis using a partial least squares regression technique and cross validation, correctly identified breed and muscle type for most samples, but carcass grades, with the exception of samples from calves, were not successfully predicted. Best calibrations for chemical composition tested by cross-validation, showed R² and standard errors of cross validation of 0.77 and 0.58% (dry matter), 0.82 and 0.48% (crude protein), 0.82 and 0.44% (ether extract). Calibrations for total ash showed a poor, and for collagen, a very poor prediction ability.     

AMP-activated protein kinase is negatively associated with intramuscular fat content in longissimus dorsi muscle of beef cattle

Marbling, or intramuscular fat, is an important factor in meat quality. As a key regulator of lipid metabolism, AMP activated protein kinase (AMPK) may be associated with intramuscular fat accumulation. Our objective was to evaluate the relationship among AMPK and its associated signaling mediators, with marbling and lean growth in beef cattle. Steers with high intramuscular fat content (High IMF, 5.71 ± 0.36%, n = 5) and low intramuscular fat content (Low IMF, 2.09 ± 0.19%, n = 5) were selected. High IMF was associated with increased tenderness (P < 0.05) and backfat thickness (P < 0.01). Muscle weights were higher in Low compared to High IMF (P < 0.05). High IMF steers had a reduced AMPK activity (P < 0.01), reduced acetyl-CoA carboxylase phosphorylation (P < 0.05), and reduced total mTOR (P = 0.02) content. Data provide evidence that AMPK is involved in IMF deposition in beef cattle.     

乌珠穆沁羊与小尾寒羊一磷酸腺苷激活蛋白激酶酶活性与肉品质的关系研究

摘 要：目的 研究乌珠穆沁羊与小尾寒羊不同生长阶段、不同部位骨骼肌一磷酸腺苷激活蛋白激酶(adenosine monophosphate-activated protein kinase,AMPK)活性、糖酵解与肉质相关指标的内在变化规律。方法 通过夹心酶联免疫吸附法测定6月龄和8月龄乌珠穆沁羊与小尾寒羊的股二头肌、背最长肌与臂三头肌AMPK活性,比色法测定乳酸(lactic acid,LA)含量,微量法测定肌糖原含量和分光光度法测定己糖激酶(hexokinase,HK)含量以及常规法测定肉品质等相关性指标。结果 两个品种的肉羊之间AMPK活性无显著差异(P>0.05);AMPK活性升高同时pH24值、L*值、b*值与剪切力降低(P<0.05),LA、肌糖原含量、a*值和HK活性升高(P<0.05)。被激活的AMPK能够刺激产能过程糖酵解的HK活性、磷酸果糖激酶和丙酮酸激酶,酶活性与LA含量呈正相关,宰后呼吸方式的改变导致pH快速下降剪切力增大,嫩度与熟肉率降低。结论 表明宰后羊肉AMPK活性与糖酵解和肉品质之间存在一定的影响。AMPK活性以及糖酵解的程度不同,可能导致了肉的剪切力、瘦肉率以及嫩度等差异,AMPK活性增强糖酵解的关键酶被激活活性增加,加快糖酵解进程从而影响肉品质。     

Rapid measurement and control of the moisture content of compost using near-infrared spectroscopy

In a compost fermentation of soybean-curd (tofu) refuse, the effects of the moisture content of the compost on the compost reaction were studied. The moisture content of the compost was a very important factor for good fermentation. Near-infrared spectroscopy (NIRS) was applied to the determination of the moisture content of the compost. The reflected rays in the wavelength range between 400 and 2500 nm were measured at 2 nm intervals. The absorption of water was observed at three wavelengths, 960, 1406 and 1888 nm. To formulate a calibration equation, a multiple linear regression analysis was carried out between the near-infrared spectral data at 960 nm (sample number, n = 50) and on the moisture content obtained using a drying method. The values of the simple correlation coefficient and the standard error of calibration were 0.987 and 1.33%, respectively. To validate the calibration equation obtained, the moisture content in the prediction sample set (n = 35) not used for formulating the calibration equation was calculated using the calibration equation, and compared with the values obtained using the drying method. Good agreement was observed between the results of the drying method and those of the NIRS method. The simple correlation coefficient and standard error of prediction were 0.979 and 1.85%, respectively. Then, the NIRS method was applied to a practical situation in which the moisture content was measured and controlled during the compost fermentation, and good results were obtained. The study indicates that NIRS is a useful method for measurement and control of the moisture content in the compost of soybean-curd refuse.     

The development of near-infrared spectroscopy (NIRS) calibration for prediction of ash content in legumes on the basis of two different reference methods

The aim of this study was to develop optimal NIRS calibration for ash content prediction in legumes by using the thermogravimetric (TGA) and gravimetric (GA) analytical methods. The calibration was performed on the basis of whole and structured sample sets (n = 143 and n = 99, respectively). Samples were scanned using a Rapid Content Analyzer in reflectance mode (400–2500 nm). Different mathematical treatments of the spectra preceded modified partial least squares (MPLS) regression analyses. The performance of the models was assessed by cross validation and external validation (n = 44). Models developed for the whole sample set on the basis of the TGA and GA methods were characterised by standard error of calibration (SEC) ranged from 0.28 to 0.50, standard error of cross validation (SECV) ranged from 0.43 to 0.60, coefficient of determination (R²) ranged from 0.97 to 0.89, explained variance (1 − VR) ranged from 0.94 to 0.85 and residual predictive deviation (RPD) ranged from 4.23 to 2.68, respectively. Models developed for the structured sample set on the basis of the TGA and GA methods were characterised by standard error of calibration (SEC) ranged from 0.32 to 0.42, standard error of cross validation (SECV) ranged from 0.53 to 0.56, coefficient of determination (R²) ranged from 0.97 to 0.94, explained variance (1 − VR) ranged from 0.91 to 0.89 and residual predictive deviation (RPD) ranged from 3.52 to 2.98, respectively. The obtained results showed the potential of NIRS method to accurately predict the ash content of legume grass samples that correspond to ash content determined by the TGA and GA methods.     

米糠粗蛋白、粗脂肪以及粗纤维含量的近红外预测模型的建立

近红外光谱技术是一种快速无损检测物质含量和鉴别物质的现代分子光谱分析技术.本研究选用分别来自南北方共200个米糠样品(100个粳米米糠、100个籼米米糠),经过理化数据检测、近红外参数优化、光谱信息采集、光谱数据预处理、模型建立及模型优化等步骤,最终建立粳米米糠、籼米米糠及总米糠的粗蛋白、粗脂肪、粗纤维的预测模型,所建...     

近红外光谱技术快速检测狭鳕水分、脂肪和蛋白质的含量

采集63个具有代表性的狭鳕鱼样品,通过拟合狭鳕鱼鱼肉的近红外漫反射光谱与水分、脂肪和蛋白质的含量,建立近红外定量分析模型。采用偏最小二乘法(PLA)进行拟合,应用内部交叉检验的方法进行检验与验证,同时用不同光谱预处理方法和主因子数对光谱进行比较分析,得出最佳预处理方法和主因子数。水分、脂肪和蛋白质的模型相关系数分别达到0.9342、0.8125、0.9113,相对分析误差(RPD)达到3.4、2.3、3.1。结果表明水分、脂肪和蛋白质的近红外模型具有较好的准确性和稳定性,能够达到快速无损测定狭鳕水分、脂肪和蛋白质的目的。      

Predicting of intramuscular fat content in pork using near infrared spectroscopy and multivariate analysis

The potential of near infrared (NIR) spectroscopy combined with chemometrics methods was studied to rapidly detect intramuscular fat (IMF) content in pork. Near infrared diffuse reflectance spectra were recorded both with an FT-NIR and a USB4000 spectrometer. The data analysis was compared on different sample preparation, spectral range and spectra pretreatment. According to calibration statistics, best calibration for IMF showed R²_cal of 0.94, R²_val of 0.92, RMSEC of 0.233, RMSEP of 0.462 and RPD of 2.29. The prediction of IMF content for minced samples was more accurate than that for intact samples. The spectra obtained using FT-NIR contained much information correlating to the IMF content than the Vis-NIR spectra of USB4000. The results showed that NIR spectroscopy technique can be used to determine the IMF content in pork as a rapid, convenient, and feasible analysis tool.     

Prediction of pork quality with near infrared spectroscopy (NIRS): 1. Feasibility and robustness of NIRS measurements at laboratory scale

The objective was to study prediction of pork quality by near infrared spectroscopy (NIRS) technology in the laboratory. A total of 131 commercial pork loin samples were measured with NIRS. Predictive equations were developed for drip loss %, colour L*, a*, b* and pH ultimate (pHu). Equations with R(2)>0.70 and residual prediction deviation (RPD)≥1.9 were considered as applicable to predict pork quality. For drip loss% the prediction equation was developed (R(2) 0.73, RPD 1.9) and 76% of those grouped superior and inferior samples were predicted within the groups. For colour L*, test-set samples were predicted with R(2) 0.75, RPD 2.0, colour a* R(2) 0.51, RPD 1.4, colour b* R(2) 0.55, RPD 1.5 and pHu R(2) 0.36, RPD 1.3. It is concluded that NIRS prediction equations could be developed to predict drip loss% and L*, of pork samples. NIRS equations for colour a*, b* and pHu were not applicable for the prediction of pork quality on commercially slaughtered pigs.     

Predicting intramuscular fat content and marbling score of pork along the longissimus muscle based on the last rib

The possibility of using IMF content/MS at the last rib to predict the corresponding fat attribute of loin chops at the 2nd last to the 7th last thoracic ribs and the mean of IMF content/MS of the whole loin joint was investigated. Linear and quadratic regression, cross‐validation analysis and analysis of variance were employed for the study. For either IMF or MS, linear and quadratic regression models had similar performance. The best mean correlation coefficients of calibration (R_c) of 0.91 and cross‐validation (R_v) of 0.88 were obtained for linear regression model of IMF content of the whole loin, while R_c of 0.90 and R_v of 0.88 were obtained for quadratic regression model of MS of the whole loin. The results indicated that IMF content and MS at the last rib had great potential for the prediction of IMF content and MS at the other ribs.