抗氧化剂对冷冻牛肉护色效果的应用研究

研究了四种抗氧化剂对冷冻牛肉的护色效果。采用Box-Behnken响应面设计法进行实验对四种抗氧化剂的用量范围进行了优化设计,并采用Design-Expert7.1.6软件进行了数据拟合。实验优化后的△a*值为0.1632,与△a*的预测值0.1524基本吻合,模型极其显著(P<0.01),方程拟合度高(R2=0.9567)。经验证后,模型选用合理有效。确定了四种抗氧化剂的最佳配比:即烟酰胺0.22%、D-异抗坏血酸钠0.019%、植酸钠0.033%、茶多酚0.027%。四种抗氧化剂对冷冻牛肉护色效果影响大小的排列顺序依次为:茶多酚>植酸钠>烟酰胺>D-异抗坏血酸钠。结合CIE L*a*b*表色系统进行视觉分析,△E*ab=1.496,与观察感觉中感觉到的色差程度为"稍有差异",此结论与感官评价"颜色较好、光泽微暗"的结论基本吻合。证明了该实验得出的最佳配比对冷冻牛肉的护色效果明显。     

The fabric defect detection based on CIE L*a*b* color space using 2-D Gabor filter

A detection algorithm based on CIE L*a*b* color space is proposed to detect various colorful fabric defects more accurately and avoid the error detection resulted from losing image information of graying. CIE L*a*b* color space is transformed from XYZ space via nonlinear transformation of RGB space. First, three features including the brightness characteristics L*, color information of a* and b* which are used to form 2-D Gabor filter in a complex number can be acquired. Genetic algorithm with the objective function in a form of energy is adopted to select optimal Gabor filter parameters. Second, filter built by flawless image is used to filter the corresponding drawbacks of image. Third, ultimate results are obtained through sliding threshold segmentation method and properly de-noising. The experiment success rate is 95.83%, which indicate that this method can detect diversiform colorful fabric defect accurately.     

Color measurement in Lab units from RGB digital images

The superficial appearance and color of food are the first parameters of quality evaluated by consumers, and are thus critical factors for acceptance of the food item by the consumer. Although there are different color spaces, the most used of these in the measuring of color in food is the L^*a^*b^* color space due to the uniform distribution of colors, and because it is very close to human perception of color. In order to carry out a digital image analysis in food, it is necessary to know the color measure of each pixel on the surface of the food item. However, there are at present no commercial L^*a^*b^* color measures in pixels available because the existing commercial colorimeters generally measure small, non-representative areas of a few square centimeters. Given that RGB digital cameras obtain information in pixels, this article presents a computational solution that allows the obtaining of digital images in L^*a^*b^* color units for each pixel of the digital RGB image. This investigation presents five models for the RGB → L^*a^*b^* conversion and these are: linear, quadratic, gamma, direct, and neural network. Additionally, a method is suggested for estimating the parameters of the models based on a minimization of the mean absolute error between the color measurements obtained by the models, and by a commercial colorimeter for uniform and homogenous surfaces. In the evaluation of the performance of the models, the neural network model stands out with an error of only 0.93%. On the basis of the construction of these models, it is possible to find a L^*a^*b^* color measuring system that is appropriate for an accurate, exacting and detailed characterization of a food item, thus improving quality control and providing a highly useful tool for the food industry based on a color digital camera.     

油脂颜色的三种表示方法及转换关系研究

应用数字色彩传感器和微控制器设计一种油脂颜色检测实验装置,检测输出油脂颜色的三基色(红、绿、蓝)信号,即RGB值。为避免RGB模型的缺点,将油脂颜色检测值转换到与设备无关的CIE表色系统,完成由RGB值向CIE–XYZ值、CIE–L*a*b*值的转换,并采用颜色检测组件HDJD–JD02对颜色模型转化公式进行校正。结果表明,油脂颜色可以基于光学和色度学理论进行描述,并可以转换到其它颜色空间。     

传统服饰云肩实物图像主色的智能检测

为解决获取传统服饰实物图像色彩耗时且缺乏准确性问题,以传统服饰的云肩为例,借助均值漂移（Mean-shift）聚类法,提出了一种检测传统服饰实物图像颜色的方法。运用单反数码相机进行实物图像采集;对所得初始图像的R、G、B3个颜色通道进行去噪处理;再将图像RGB颜色空间的特征向量转换至CIE L*a*b*颜色空间中,利用大津法阈值原理（自适应阈值算法）分割被测图像中云肩实物与背景;最后采用Mean-shift聚类算法,将被测图像的颜色像素分割为若干有效的集群,同时从这些集群中提取云肩主要色彩。实验结果表明,该算法可较为准确地从云肩图像中提取主色,且当Mean-shift聚类算法的带宽被设定为0.05时,分类颜色结果更为准确。     

Ground truth study on fractal dimension of color images of similar texture

Fractal dimension (FD) estimation has become most popular in the field of image analysis and applications; especially estimating the roughness and smoothness of complex objects. In this present investigation, we are considering three most popular methods in the controlled images acquisition experimental setup for eight colored fabrics of the same texture, material property, and illumination. The concept of previous work and the results obtained by this ground truth experiment were discussed to indicate whether FD might be a worth useful metric for the study of color images with self-similarity, such as textures! Interestingly, we found ambiguous FD results here and tried to explain such phenomenon in relation to the development of CIE-based human perception model as texture perception are well associated with the viewing parameters and observer that perceives the image in terms of spatial distribution of color intensity.     

新闻纸的白度、色度与不透明度

本文通过对目前新闻纸市场上新闻纸的白度、色度和不透明度的调查，结合本厂的实践提出了对新闻纸的ISO白度、CIE白度、L^＊、a^＊、b^＊值和不透明度的合理控制范围。     

Effects of succinate and pH on cooked beef color

Two experiments were conducted to assess the effects of succinate and pH on cooked beef color. In experiment 1, ten strip loins (M. longissimus lumborum) were divided in half and assigned to either non-enhanced control or 2.5% succinate. Each half-loin was cut into steaks, packaged in vacuum or 80% oxygen, and stored at 1 °C for 0, 6, or 12 days. Steaks were cooked to either 66 °C or 71 °C. Succinate increased (P < 0.05) steak pH, raw a* values, and interior cooked redness when packaged in high oxygen. In experiment 2, to assess the role of succinate in raw and cooked color, succinate or ammonium hydroxide was added to ground beef patties to result in a common meat pH (5.9). At a similar pH, succinate had greater metmyoglobin reducing activity and internal cooked redness compared with ammonium hydroxide (P < 0.05). In addition to ingredient-based changes in muscle pH, succinate may influence color by regenerating reducing equivalents.     

Genetic and nongenetic factors associated with milk color in dairy cows

Milk color is one of the sensory properties that can influence consumer choice of one product over another and it influences the quality of processed dairy products. This study aims to quantify the cow-level genetic and nongenetic factors associated with bovine milk color traits. A total of 136,807 spectra from Irish commercial and research herds (with multiple breeds and crosses) were used. Milk lightness $\left(\stackrel{?}{\text{L}}*\right)$, red-green index $\left(\stackrel{?}{\text{a}}*\right)$ and yellow-blue index $\left(\stackrel{?}{\text{b}}*\right)$ were predicted for individual milk samples using only the mid-infrared spectrum of the milk sample. Factors associated with milk color were breed, stage of lactation, parity, milking-time, udder health status, pasture grazing, and seasonal calving. (Co)variance components for $\stackrel{?}{\text{L}}*,\stackrel{?}{\text{a}}*$, and $\stackrel{?}{\text{b}}*$ were estimated using random regressions on the additive genetic and within-lactation permanent environmental effects. Greater $\stackrel{?}{\text{b}}*$ value (i.e., more yellow color) was evident in milk from Jersey cows. Milk $\stackrel{?}{\text{L}}*$ increased consistently with stage of lactation, whereas $\stackrel{?}{\text{a}}*$ increased until mid lactation to subsequently plateau. Milk $\stackrel{?}{\text{b}}*$ deteriorated until 31 to 60 DIM, but then improved thereafter until the end of lactation. Relative to multiparous cows, milk yielded by primiparae was, on average, lighter (i.e., greater $\stackrel{?}{\text{L}}*$), more red (i.e., greater $\stackrel{?}{\text{a}}*$), and less yellow (i.e., lower $\stackrel{?}{\text{b}}*$). Milk from the morning milk session had lower $\stackrel{?}{\text{L}}*,\stackrel{?}{\text{a}}*,$ and $\stackrel{?}{\text{b}}*$ Heritability estimates (±SE) for milk color varied between 0.15 ± 0.02 (30 DIM) and 0.46 ± 0.02 (210 DIM) for $\stackrel{?}{\text{L}}*$, between 0.09 ± 0.01 (30 DIM) and 0.15 ± 0.02 (305 DIM) for $\stackrel{?}{\text{a}}*$, and between 0.18 ± 0.02 (21 DIM) and 0.56 ± 0.03 (305 DIM) for $\stackrel{?}{\text{b}}*$ For all the 3 milk color features, the within-trait genetic correlations approached unity as the time intervals compared shortened and were generally <0.40 between the peripheries of the lactation. Strong positive genetic correlations existed between $\stackrel{?}{\text{b}}*$ value and milk fat concentration, ranging from 0.82 ± 0.19 at 5 DIM to 0.96 ± 0.01 at 305 DIM and confirming the observed phenotypic correlation (0.64, SE = 0.01). Results of the present study suggest that breeding strategies for the enhancement of milk color traits could be implemented for dairy cattle populations. Such strategies, coupled with the knowledge of milk color traits variation due to nongenetic factors, may represent a tool for the dairy processors to reduce, if not eliminate, the use of artificial pigments during milk manufacturing.     

Development of a computer vision system to measure the color of potato chips

The objective of this research was to design and implement an inexpensive computer vision system for measuring the color of a highly heterogeneous food material not only in shape as well in color such as potato chips in L^*a^*b^* units from RGB images. The system was composed of (i) a digital color camera for acquiring the images in a digital format, (ii) a computer for storage the images, (c) image analysis routines integrated into a software programmed in Matlab that converts the color RGB of the food image into L^*a^*b^* units. In this way the color of potato chips can be calculated in L^*a^*b^* units over representative areas and in a reproducible way. The kinetics of color changes in potato slices during frying at four temperatures was followed using the implemented computer vision system (CVS). Color values in L^*a^*b^* units were recorded at different sampling times during frying at the four oil temperatures using the total color change parameter (ΔE). Chips fried at higher temperatures get darker as expected and showed by the CVS. The implemented computer vision system can be used to study as well foods different from potato chips by selecting their proper settings for image acquisition and digital image processing.     

Combination of digital images and laser light to predict moisture content and color of bell pepper simultaneously during drying

Optical devices are being increasingly used for more accurate and faster ways to investigate quality parameters of agricultural products. The main task of this research is to evaluate the use of a CCD camera in combination with laser diodes emitting at 532 nm and 635 nm to monitor changes in moisture content of red, yellow and green bell pepper during drying. Moreover, the feasibility of using the CCD camera alone to analyze color changes during drying, in alternative to the colorimeter, is assessed. Results showed that scattering area and light intensity were able to predict moisture content changes of bell pepper during drying. While excellent correlations were obtained for yellow colored samples (R = 0.93 and RMSEP = 7.28), the behavior of green and red wavelengths in peppers with red and green color, respectively, may raise some doubt on the ability to predict moisture content (R = 0.33 and RMSEP > 22). Additionally, light scattering varied according to the different depths on the surface where the images were taken. Furthermore, it was concluded that a change in tissue structure during drying may have caused dispersion of photons through the surface resulting in varying degrees of scattering. The presented technique based on a digital camera and laser diodes shows the potential to be applied in the future as a fast and modern method for in-line measurements of monitoring moisture content during drying. Digital images in terms of RGB values have been demonstrated to be a promising alternative to monitor changes of L^∗ (R = 0.87 and R = 0.90), and a^∗ values (R = 0.93 and R = 0.97), during drying of yellow and green pepper. Extensive studies are still required to determine the suitability of digital images for analysis of b^∗ values at different colors of bell pepper.     

Changes in physico-chemical, microbiological, textural and sensory attributes during ripening of dry-cured foal salchichón

The changes in the physico-chemical, microbiological, textural and sensory attributes of foal salchichón were followed during ripening. Foal salchichón samples were taken at 0 days (mix before stuffing), and after 7, 14, 21, 28, 35, 42 and 49 days of ripening. The final a_w was 0.82, whereas pH values stayed around their initial values. TBAR'S values increased significantly (P < 0.001) during processing, from 0.44 to 2.26 mg/kg of sausage. Ripening time also affected the lightness (L*), redness (a*) and yellowness (b*) (P < 0.001). Hardness, gumminess and chewiness increased (P < 0.001) from 0.96, 0.6 and 0.47 to 46.92 kg/cm², 21.34 kg/cm² and 15.14 kg, respectively during processing, whereas cohesiveness and springiness values decreased during ripening. Lactic acid bacteria increased slowly in number and a large increase of Micrococcaceae was noticed. Regarding sensorial characteristics, foal salchichón samples showed high values for intensity of flavour (7.22 ± 0.44), hardness (7.33 ± 0.71) and dryness (6.67 ± 0.71) and low scores for acid taste (1.67 ± 0.71) and saltiness (3.11 ± 0.6).     

Effects of agricultural practices on instrumental colour,mineral content,carotenoid composition,and sensory quality of mandarin orange juice,cv. Hernandina

BACKGROUND: Frequent consumption of fruits and vegetables is associated with a lowered risk of cancer, hypertension and heart disease, due, among other factors such as modulation of gene expression and improvement of gap junctional communication, to the presence of various forms of antioxidants present in the foods as carotenoids. Otherwise, consumers demand organic products which they believe have more flavour and are of greater benefit to the environment and human health. The effects of organic farming on CIE L*a*b* colour, mineral content, carotenoid composition and sensory quality of Hernandina mandarin juices were studied. RESULTS: Organic farming of mandarin oranges resulted in juices with higher contents of minerals and carotenoids, and of better sensory quality. For instance, organic juice contained a total concentration of carotenoids of 14.4 mg L^?1 compared to 10.2 mg L^?1 of conventional juice. CONCLUSION: Mandarin orange juices can be considered as a good source of some important nutrients, such as potassium and antioxidant chemicals, e.g. β‐cryptoxanthin. Copyright © 2008 Society of Chemical Industry     

A non-destructive digital imaging method to predict immobilized yeast-biomass

In food fermentation, many types of immobilization systems are used, such as hydrogel entrapment, where alginate is the main biopolymer. One of the important problems in industrial processes is the quantifications of biomass, since the traditional system of direct cell counting cannot be used. In this study, a simple digital imaging method to determine the biomass of yeasts immobilized into alginate capsules was developed. Important evidence of the yeasts growing inside the alginate was the change in the surface color of the capsule. Digital images were taken with different biomass concentration, and the RGB-analysis showed significant differences in the blue field. The histogram of the blue channel was used to develop a PLS multivariate calibration to predict biomass concentration. The method was validated in primary beer fermentation with good efficiency.     

Comparison of different peeling systems for kiwifruit (Actinidia deliciosa,cv Hayward)

Galicia (N.W. Spain) produces 60% of Spanish kiwifruit (Actinidia deliciosa) and 5–20% of these are ‘destrío’ fruits, which do not reach market size and the appropriate form. These rejected fruits can be processed into products, thus increasing their added value. The processing of kiwifruit always includes a peeling operation, which can be performed by different systems. The most suitable conditions for caustic peeling and thermal peeling were established. Then, the two peeling systems were compared with manual peeling with the aim of selecting the best system to remove the peel of the ‘destrío’ kiwifruit. The fruits, once harvested, were stored in a cold chamber at 0 °C. Before processing or marketing kiwifruits, it is necessary to remove them from storage in cold chamber and storage at room temperature. In this study, different storage times at room temperature before peeling kiwifruits were also tested. The best system for peeling the kiwifruit was thermal peeling as this system resulted in the lowest weight loss and preserved the green colour characteristic of the kiwifruit. The best time for peeling the kiwifruit was after 8 days of storage at room temperature, after being removed from the cold chamber.     

牛肉肠褪色反应机制及控制

对牛肉肠易氧化褪色的原因进行了研究，认为牛肉自身色素蛋白含量高及产品不饱和脂肪酸含量高，是造成牛肉肠易褪色的主要原因。同时，提出了用切断油脂自动氧化的链锁反应、螯合金属离子、调整ｐＨ值、减少氧化残留量等措施，来延缓产品褪色反应的进行。     

Cooking rate, pH and final endpoint temperature effects on color and cook loss of a lean ground beef model system

To assess the effects of pH, heating rate and endpoint temperature on instrumental and visual color of ground beef, pH was adjusted to 5.2–6.4, samples were heated at 0.7°C or 3°C/min to 55, 60, 65, 70, 75 or 80°C in a water bath. Cooking rate had no effect on cook loss, instrumental or visual color. Regression equations for linear, quadratic and/or cubic effects of pH and/or endpoint temperature were significant for most color indices. Amount of variance explained by the model and R² was increased by adding the calculated percentages of metmyoglobin and/or deoxymyoglobin to the regression models. The predicted sensory brownness score (0=very pink, 7.5=intermediate pink/brown, 15=intense brown) for samples with pH 5.75 cooked to 70°C was 9.75. Samples with a pH of 5.5 achieved this brownness score at 67°C. Samples with a pH of 5.2 achieved this brownness at 58°C.     

Red-Green-Blue分色域仿真的数码提花织物设计

针对Red-Green-Blue(RGB)分色模式不能直接作为数码提花织物分色模式的问题,通过对RGB色彩模式下单一色彩通道显色色域的分析,研究了三色通道对应的纱线色彩选择范围。并结合一组经三纬组合全显色织物组织结构,进行了数码提花织物的设计实践,之后对织物显色效果进行优化实验。研究结果表明,按照R、G、B分别对应蓝、红、黄三色纬的规则,直接使用经RGB三色通道分色产生的灰度图进行提花织物设计,可基本实现图像色彩的对应显色;而各灰度图明度值分别适度提高之后,可满足三色仿真数码提花织物的设计要求,为充分利用RGB色彩模式的分色设计价值提供了参考。     

Effects of pyruvate, succinate, and lactate enhancement on beef longissimus raw color

Beef strip loins (n=30) were divided into halves, and each half was assigned randomly to one of four injection enhancements: (1) non-enhanced control, (2) 3% pyruvate, (3) 3% succinate, and (4) 3% lactate. Steaks were cut and packaged in either vacuum, high oxygen (80% O(2)/20% CO(2)), or PVC. Color and lipid oxidation were measured on days 0, 5, and 13 of storage at 1°C. Enhancement had a significant effect on steak pH. On day 13 of storage, steaks enhanced with lactate, pyruvate, and succinate were less discolored (P<0.05) than control steaks in PVC and high oxygen. Enhancement darkened steaks (P<0.05) compared with control steaks. Succinate had the greatest and pyruvate had the least metmyoglobin-reducing activity (P<0.05). Lactate and pyruvate decreased the TBARS values of steaks packaged in PVC (P<0.05) whereas pyruvate was most effective for lowering lipid oxidation in high-oxygen packaging.     

从RGB到HSV色彩空间转换公式的修正

针对从RGB色彩空间到HSV色彩空间的转换方式为非线性变换,会产生奇异点和不稳定点的问题,对转换公式作了修正.原公式在饱和度为零时色度未定义,在低饱和度时色度不稳定,这些情况下色度为黑色、灰色或者白色,将色度分量的低值区域和高值区域分别用来表示黑白色或者偏黑和偏白的低饱和度色.不但能够消除色度奇异点和不稳定点,而且可以用单纯H分量来表述色彩图像的主色调信息,简化了图像计算的复杂度.通过分析和实验验证,方法是有效的.