Measurement of meat color using a computer vision system

The limits of the colorimeter and a technique of image analysis in evaluating the color of beef, pork, and chicken were investigated. The Minolta CR-400 colorimeter and a computer vision system (CVS) were employed to measure colorimetric characteristics. To evaluate the chromatic fidelity of the image of the sample displayed on the monitor, a similarity test was carried out using a trained panel. The panelists found the digital images of the samples visualized on the monitor very similar to the actual ones (P < 0.001). During the first similarity test the panelists observed at the same time both the actual meat sample and the sample image on the monitor in order to evaluate the similarity between them (test A). Moreover, the panelists were asked to evaluate the similarity between two colors, both generated by the software Adobe Photoshop CS3 one using the L*, a* and b* values read by the colorimeter and the other obtained using the CVS (test B); which of the two colors was more similar to the sample visualized on the monitor was also assessed (test C). The panelists found the digital images very similar to the actual samples (P < 0.001). As to the similarity (test B) between the CVS- and colorimeter-based colors the panelists found significant differences between them (P < 0.001). Test C showed that the color of the sample on the monitor was more similar to the CVS generated color than to the colorimeter generated color. The differences between the values of the L*, a*, b*, hue angle and chroma obtained with the CVS and the colorimeter were statistically significant (P < 0.05–0.001). These results showed that the colorimeter did not generate coordinates corresponding to the true color of meat. Instead, the CVS method seemed to give valid measurements that reproduced a color very similar to the real one.     

Quality control of Toxoplasma gondii in meat packages: standardization of an ELISA test and its use for detection in rabbit meat cuts

Toxoplasma gondii causes severe disease both to man and livestock and its detection in meat after slaughtering requires PCR or biological tests. Meat packages contain retained exudate that could be used for serology due to its blood content. Similar studies reported false negative assays in those tests. We standardized an anti-T. gondii IgG ELISA in muscle juices from experimentally infected rabbits, with blood content determination by cyanhemoglobin spectrophotometry. IgG titers and immunoblotting profiles were similar in blood, serum or meat juice, after blood content correction. These assays were adequate regardless of the storage time up to 120 days or freeze-thaw cycles, without false negative results. We also found 1.35% (1/74) positive sample in commercial Brazilian rabbit meat cuts, by this assay. The blood content determination shows ELISA of meat juice may be useful for quality control for toxoplasmosis monitoring.     

生物传感器法检测葡萄汁中葡萄糖含量

采用葡萄糖氧化酶与过氧化氢电极,在0.2 mol/L的磷酸盐缓冲液（pH 7.2）和1‰的葡萄糖标准溶液反应体系中,建立葡萄汁中葡萄糖含量检测的生物传感器分析方法。结果表明,在葡萄糖质量浓度为0～1 000 mg/L的范围内生物传感器法测定葡萄糖含量的线性良好;线性回归方程为y=0.994 8x-3.081,相关系数R2=0.999 9;稳定性好,相对标准偏差（RSD）=1.63%;加标回收率为96.0%～102.4%;专一性强,只对葡萄糖进行专一性测定。     

果胶酶澄清菠萝汁最佳工艺研究

用果胶酶对菠萝浆进行酶解及最佳澄清工艺条件试验。单因素试验研究了果胶酶用量、酶解温度和酶解时间分别对菠萝汁透光率、可溶性固形物、出汁率、果胶含量的影响。在此基础上,通过二次正交旋转回归试验,得出了酶解条件的回归方程,确定了果胶酶对菠萝汁澄清的最佳工艺条件为果胶酶用量为80mg/kg、温度25℃、时间为60min。     

Evaluation of enzymatic treatment of peach juice using response surface methodology

BACKGROUND: This work aimed to assess peach juice clarification using enzymatic treatment. The enzymatic hydrolysis was performed to reduce the juice viscosity and pulp content, and consequently to increase juice extraction. The hydrolysis conditions were optimized by the response surface methodology, where the influence of temperature, amount and type of enzyme and time of reaction were investigated. RESULTS: Two commercial pectinase preparations (AFP L3 and ULTRA SP WOP from Novozymes) as well as a cellulase (R10 from Onozuka) were tested. The hydrolysis using Pectinex AFP L3 (Novozymes) at 25 °C for 60 min presented the best results of pulp (48%) and viscosity (68%) reduction. CONCLUSION: Physical and chemical analyses showed that the enzymatic treatment is effective for reduction of peach pulp viscosity, pulp content and turbidity and does not influence other juice parameters such as pH, total acidity, vitamin C and soluble solids. Copyright © 2007 Society of Chemical Industry     

响应面法优化紫薯汁糖化工艺研究

以紫薯液化汁为原料,采用单因素试验对紫薯汁的糖化工艺进行研究,并通过响应面法优化得到紫薯汁糖化最佳工艺参数。结果表明,各因素对紫薯液化汁糖化的影响大小依次为时间、糖化酶添加量、温度和pH值。并得到紫薯汁糖化最佳工艺参数:温度60℃、pH值4.5、糖化酶添加量1.0%、糖化酶作用时间2.0 h。在此条件下,紫薯汁总糖含量为38.691 g/L。     

Substrate utilization during incubation in meat juice medium of psychrotolerant clostridia associated with blown pack spoilage

Several new species of psychrophilic or psychrotolerant clostridia have been identified in recent years. Some of these may be involved in ‘blown pack’ spoilage (BPS) of vacuum packaged beef. Organisms that cause BPS must produce large volumes of gas while utilizing substrates available in raw meat. Therefore, Clostridium algoriphilum, Clostridium algidixylanolyticum, Clostridium bowmanii, Clostridium frigoris, Clostridium frigidicarnis, Clostridium gasigenes, Clostridium lacusfryxellense, Clostridium psychrophilum, Clostridium tagluense and Clostridium vincentii were grown in meat juice medium (MJM), and changes in substrate concentrations were monitored to assess the potential for gas production by each organism. All 10 species were able to grow exponentially on glucose with simultaneous hydrolysis of glycogen, reaching maximum values for absorbance at 600 nm of 0.3–1.90. All ceased growing when glucose and glycogen were still detectable in the growth medium. C. frigidicarnis utilized most of the amino acids available in MJM and reduced the concentration of total amino acids by 10 mM. The other 9 species caused little or no reduction in amino acid concentrations. C. algidixylanolyticum and C. frigidicarnis utilized glucose, glycogen and lactate simultaneously during growth and after growth ceased. C. algoriphilum and C. frigoris commenced utilization of lactate, while continuing utilization of glucose and glycogen, only after growth ceased, but utilization of lactate by C. algoriphilum was weak. C. psychrophilum ceased utilization of glucose and glycogen but initiated weak utilization of lactate after growth ceased. The other 5 species did not utilize any substrate after growth ceased. The utilization of glucose, glycogen and relatively large amounts of lactate by C. algidixylanolyticum, C. frigoris, and C. frigidicarnis after growth ceased indicates that these organisms have the potential to cause BPS. The other 7 species appear to lack such potential.     

利用果胶酶澄清西番莲果汁的工艺研究

通过单因素试验分析探讨了果胶酶的种类、添加量、pH、温度和时间对西番莲果汁澄清效果的影响,确定最佳的澄清工艺参数。     

Determination of added fat in meat paste using microwave and millimetre wave techniques

By evaluating the sensitivity of measurement parameters such as dielectric constant and microwave loss to fat content, several microwave and millimetre methods were compared to identify optimal frequency measurement bands. The results showed that the optimum frequency range lay between 8 and 20GHz where these parameters vary linearly, by up to a factor of 8, as fat is increased to 50% volume. A narrowband waveguide sensor cell was designed and constructed for this optimum range. The imaginary part (ε') of the complex permittivity demonstrated a better measurements resolution for determining fat content than the real part (ε'). The waveguide method has excellent repeatability as indicated by low relative standard deviation (RSD<4.88%). Temperature and sample density had minimal impact on the accuracy, repeatability and robustness of the final measurement system. A method of mixtures model for complex permittivity was shown to be a useful predictor of fat content.     

Prospects for new technology of meat processing in Japan

This review starts by introducing the history and underlying culture of meat production and consumption in Japan since early times, and the effects of social change on these parameters. Meat processing in Japan is described, and certain other related papers are also introduced. Automatic machines for meat cutting have been developed by the Japanese food industry and are currently being used throughout the world, particularly in Europe. Soft meat products specially produced for the elderly, along with diet meat products low in salt and calorie content for middle aged persons have recently gone into production. The intensification of color formation of meat using naturally occurring materials, and tenderization of sausage casing are discussed.     

基于柠檬提取液的银纳米颗粒绿色制备工艺优化

为实现绿色制备银纳米颗粒,研究以硝酸银为原料,采用柠檬提取液为还原剂和稳定剂,在水溶剂环境中采用生物法绿色合成银纳米颗粒。研究探讨了柠檬提取液(柠檬汁、柠檬皮醇提液、柠檬皮水提液)用量,硝酸银浓度,pH调节剂,反应时间,反应温度等因素对银纳米颗粒粒径、形貌、稳定性的影响,并借助紫外-可见分光光度法(UV-Vis)、SEM对银纳米颗粒进行表征。通过工艺优化,分别确定了以柠檬汁、柠檬皮醇提液、柠檬皮水提液为原料的银纳米颗粒最佳制备工艺,所得银纳米颗粒都具有分散性能良好,颗粒均匀,粒径范围为70 nm左右,其中以柠檬皮醇提液工艺制备银纳米颗粒的形貌及稳定性最佳,即硝酸银1.0 mmol/L、柠檬皮醇提液9 mL、反应时间12 min、pH调节剂为1 mol·L^-1的NaOH。该工艺采用生物法合成银纳米颗粒,绿色安全、环境友好,具有较好的实际应用价值。     

生姜汁在鹅腿肉嫩化中的应用研究

以剪切力为指标研究生姜汁对鹅腿肉的嫩化效果,通过单因素实验对生姜汁浓度、pH、处理温度进行了研究,并且进一步通过正交实验选择出最佳嫩化工艺。结果表明:生姜汁对鹅腿肉的嫩化效果十分显著(P<0.01),生姜汁对鹅腿肉嫩化的最佳工艺条件是:生姜汁浓度6%、pH6.0、处理温度为50℃。     

南果梨汁响应面复合酶法制取工艺优化

本文以南果梨为原料,研究了复合酶法制取南果梨汁最优工艺。通过单因素实验研究复合酶添加量、酶解时间、果胶酶与纤维素酶配比和酶解温度对南果梨出汁率和可溶性固形物含量的影响;在此基础上,采用Box-Behnken实验设计法,优化复合酶酶解南果梨汁工艺参数,以提高南果梨出汁率和可溶性固形物含量。结果表明:在复合酶添加量0.15%、酶解时间119 min、酶比例3∶1、酶解温度42℃的条件下,南果梨出汁率达78.15%,与理论值77.42%基本相符（相对误差0.93%）;与未经酶处理相比,出汁率提高了12.92%,可溶性固形物含量提高了1.72%。由实验结果可知,经复合酶酶解后南果梨出汁率和可溶性固形物含量等相关理化指标均有显著提高。      

胡萝卜制汁常规工艺的改进

通过胡萝卜制汁常规工艺的改进,确定一种新的胡萝卜制汁工艺方法：即对未去皮胡萝卜进行低温（65℃）,长时间（70min）蒸汽保温处理。改进工艺后胡萝卜出汁率提高了20％。     

Optimization of enzymatic clarification of green asparagus juice using response surface methodology

Enzymatic clarification conditions for green asparagus juice were optimized by using response surface methodology (RSM). The asparagus juice was treated with pectinase at different temperatures (35 °C-45 °C), pH values (4.00-5.00), and enzyme concentrations (0.6-1.8 v/v%). The effects of enzymatic treatment on juice clarity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity were investigated by employing a 3-factor central composite design coupled with RSM. According to response surface analysis, the optimal enzymatic treatment condition was pectinase concentration of 1.45%, incubation temperature of 40.56 °C and pH of 4.43. The clarity, juice yield, and soluble solid contents in asparagus juice were significantly increased by enzymatic treatment at the optimal conditions. DPPH radical-scavenging capacity was maintained at the level close to that of raw asparagus juice. These results indicated that enzymatic treatment could be a useful technique for producing green asparagus juice with high clarity and high-antioxidant activity. PRACTICAL APPLICATION: Treatment with 1.45% pectinase at 40.56 ° C, pH 4.43, significantly increased the clarity and yield of asparagus juice. In addition, enzymatic treatment maintained antioxidant activity. Thus, enzymatic treatment has the potential for industrial asparagus juice clarification.     

响应面法优化复合益生菌发酵枸杞汁的工艺研究

以宁夏枸杞干果为主要原料,利用复合益生菌进行发酵。通过单因素和响应面试验设计,分别考察菌种比例、料水比、接种量和发酵时间对发酵枸杞汁品质的影响。结果表明,最佳发酵条件为复合益生菌配比为植物乳杆菌∶肠膜明串珠菌∶嗜热链球菌∶保加利亚乳杆菌=3∶3∶2∶1,料水比（枸杞干果∶水）为1∶9（g∶mL）,接种量5%,发酵时间8 h。发酵后测得发酵枸杞汁中的乳酸含量为432 mg/100 mL,活菌数为2.3×108 CFU/mL,总糖含量为155 mg/100 mL,总黄酮含量为0.25 mg/100 mL,蛋白质含量为0.2 g/100 mL,感官评分达到96分;发酵枸杞汁颜色为鲜亮的橘红色,口感细腻柔和,发酵香气浓郁且具有枸杞特征滋味。     

Determination of the boar taint compound skatole in meat juice by means of stable isotope dilution analysis-direct immersion-solid phase microextraction-gas chromatography/mass spectrometry

A novel SIDA-DI-SPME-GC/MS procedure for the quantitation of skatole in pork meat juice was developed and validated as a substitute for back fat sample analysis. System suitability was evaluated by determining the correlation between skatole concentrations in a subset of 38 paired meat juice and back fat samples selected from 90 fattened boars. High correlation was observed between both matrices and conclusions about the partitioning of skatole as well as of androstenone between fat and lean compartments in vivo were drawn.     

果汁中微生物检测技术的研究进展

微生物是影响果汁质量安全的重要因素,目前果汁微生物检测的方法主要是传统的培养基培养法,且检测的微生物种类较少,没有覆盖到影响果汁品质的多数微生物。随着果汁工业的迅速发展,消费者对食品安全需求的提高,急需寻求多种快速、简便方法相结合检测果汁中的微生物。本文介绍了当前微生物的检测方法,包括形态学方法、生理生化试剂盒、免疫学技术、仪器分析技术和分子生物学技术等,分析了各方法的优缺点和适用性,为果汁中微生物的检测分析提供参考。     

近红外光谱测定苹果饮料中原果汁含量

提出了一种遗传算法优化支持向量机参数的近红外光谱技术对苹果饮料中原果汁含量的快速测定方法。在确定光谱数据预处理方法的基础上,通过遗传算法对支持向量机(SVM)预测模型的各项参数进行寻优,将优化出的参数代入SVM预测模型中,得到基于遗传算法的SVM模型,利用此模型对苹果饮料中原果汁含量进行预测研究。结果表明,建立的SVM模型对预测集的决定系数为0.9757,能快速测定苹果饮料中的原果汁含量。      

响应面法优化三相分离法提取河蚬汁多糖的工艺研究

目的 响应面法优化三相分离法提取河蚬汁(Corbicula fluminea juice,CFJ)中活性多糖的工艺.方法 首先对河蚬汁的基本成分进行分析,然后利用三相分离法(three-phase partitioning,TPP)从河蚬汁中提取多糖,以硫酸铵质量分数、叔丁醇与河蚬汁体积比、提取温度和时间作为单因素变量...