食品物性学9的光学性质

1、9 食品的光学性质颜色与食品工业颜色是食品加工中主要内容之一，或者保护或者改变。颜色对味觉、嗅觉、食欲、情绪等心理及生理有不可忽视的作用。颜色是评价与检测食品质量的主要指标，由此开发的仪器越来越多。基本要点人的视觉对光谱的混合能力很强，但对光谱的分析能力很差。决定物体颜色的因素是光源光谱和物体对各色光的反射率。各波长光谱的强度分布与物质无关，由其温度决定。食品形态分级与鉴别Line Scan Apple ImagesVIS/NIR Reflectance Characteristics of Golden Delicious食品成份分析与检测薯片在线检测Multispectral Fluore

2、scence Imaging SystemChlorophyll Fluorescence of Soybean LeavesMULTISPECTRAL SUB-IMAGE FOR TEXTURAL ANALYSISNormalSepticemiaCadaverTEXTURE ANALYSIS USING FAST FOURIER TRANSFORM Abnormal vs. NormalFILTER WAVELENGTH : 542 nmSKIN-TEARNORMALTUMORBRUISED颜色光学基础光线并不带颜色光源太阳太阳光谱相对能量光源标准温度与颜色基本物理量光度、光通量 （流明lm

3、）照度 （流明/平方米）发光强度cd 坎德拉强度 （流明/圆锥角，坎德拉）亮度亮度 （cd/m2）三原色三原色的亮度按原比例增加或减少时，调制色不变，但亮度等于三原色亮度之和。三原色三原色假同色 混色组成，即不同光谱组合而成。真同色 同一光谱组成。颜色与光谱 牛顿色盘能混合成白色的两种单色光，称为互补色牛顿色盘RGB表色系RGB表色系RGB-XYZ表色系XYZ表色系XYZ表色系颜色辨别阈颜色辨别阈孟塞尔色圆孟塞尔色圆孟塞尔色圆奥斯特瓦尔德颜色立体Hunter LabHunter LabCIE Lab表色立体CIE Lab表色立体CIE Lab表色立体彩度色调角色差色差与视觉比较色差程度E (L

4、,a,b)微量(trace)0.0-0.5轻微(slight)0.5-1.5能感觉到(noticeable)1.5-3.0明显(obvious)3.0-6.0很大(much)6.0-12.0截然不同(very much)12.0以上Measuring pork color: effects of bloom time, muscle, pH and relationship to instrumental parameters M.S. Brewer a,*, L.G. Zhu a, B. Bidner b, D.J. Meisinger c, F.K. McKeith bDepartment

5、 of Food Science and Human Nutrition, University of Illinois, 399 Bevier Hall, 905 S. Goodwin Avenue, Urbana, IL 61801, USAL*, a*, and b* values, hue angle, chroma and visual color were determined. Color was evaluated using HunterLab (illuminants A, C, D65 and F) and Minolta (illuminants C and D65)

6、Spectrocolorimeters.hue angle=tan-1 (b*/a*).chroma=(a*2+b*2)1/2.LT had the highest L* value (51.31; TR=39.93) and hue angle (59.36; TR=46.94), and the lowest a* (7.52; TR=12.88) value. L* value was unaffected by bloom time; hue angle stabilized after 5 min, a* and b* values after 10 min and chroma after 20 min. Using the Minolta/illuminant D65, visual color best correlated with b* and L* values (r=-0.94 and -0.89) of LT. Using the Hunter/illuminant C, visual color correlated with L* value of LT, GM, BF and SM (r -0.90 for each). Overall, the instrumental measure that bes