肉制品中色差检测方案

智能文字提取功能测试中

Manufacturing &DISTRIBUTIONBYHAL GOOD Physical Property Testing Having the safest food in the world won't guarantee customers. Color and texture add to the enjoyment ofeating. Here’s how these factors can enhance the palatable properties in the food. Methods of Measuring Food Color OLDEN POTATO CHIPS ORYEL-clowish orange juice? Color is animportant attribute to the food in-dustry. Consumers make purchasing deci-sions based on overall appearance. Andoften， color and flavor are directly related.Manufacturing processes， such as extrusionand baking， and ingredient color can affectfinal color. To obtain and maintain the de-sired color， monitoring and controlling in-1gredient color through the manufacturinggprocess is essential. Color is assessed for several reasons：·To determine and document ingredienteffect on product color； ·To determine color change as a result ofstorage or processing； ·To ensure consistency of ingredient colorfor QC purposes； and · To determine conformance to final prod-uct quality specification. Visual color assessment has severalshortcomings. Reliable visual evaluationsrequire control of multiple variables： spec-tral quality， intensity and angular size ofthe light source； direction from which thelight strikes the sample； the direction inwhich the sample is viewed； the distancebetween specimen and color standard； andthe observer's spectral response. Colorsthat fall between visual color standards，within the visual color system in use，areoften difficult to communicate to other in-dividuals. Finally， visual color assessmentis subjective，tiring and tedious. Using _- color measurement instruments is obvi-nously a better， more objective method tocheck ingredient color and to evaluate theprocess efficiency in obtaining or main-taining the desired product color. Methods and instruments for color)rmeasurement are selected based on the op-tical characteristics of the food product： e- · Opaque Food Seen wholly by reflectedlight， this group includes fruit， crackers，ccorn flakes， cheese puffs， flour， tomato juice， cheese and meat. ·Translucent Food Seen partially by re-flected and partially by transmitted light；rmany fruit juices， jams and custards fallinto this category. ·Transparent Food Seen wholly by trans-mitted light； clear juices， wines， jellies，gelatins， vegetable oil and soft drinks are inthis category. The best way to measure color ofopaque liquids， opaque solids， pastes， pow-ders and small granules is using a 45°/o°geometry instrument with a horizontal The best way to measure color ofopaque liquids，opaque solids， pastes， powders and small granules isusing a 45°/o° geometry instrument with ahorizontal sample port. sample port. This instrument geometry il-luminates the sample at a45° angle and ismeasured at a perpendicular angle (o°).This is similar to how we view sampleswith our eyes. Liquid sample is poured intoa sample cup and placed over the instru-ment port for measurement； flat slab sam-ples-blocks of cheese or slices of meatare placed directly on the sample port. Asample port aperture with glass insert pre-vents juices from dripping into the instru-ment. To measure coarse granules， flakes，chips and disks-cookies and crackers-the best system is a 45°/o°geometry in-strument with circumferential illumina-tion and a large measurement port. Thisgeometry compensates for the directionaleffect of the sample and the large measure-ment area provides a good optical averageof non-uniform samples. For continuousmeasurement of crackers and cookies， anon-line color monitoring system can bemounted over a moving web to providereal-time color data. Translucent samples require specialhandling. The color of a translucent sam-ple changes when the light path lengthgoing through changes. The path length must be fixed.A "ring and disk" assemblyis used to measure this type of sample. Acup with ring， disk and sample is placedon the 45°/o° geometry instrument portfor measurement. Transparent food is measured by trans-mission instead of reflection. Brewed tea，for example， is poured into a transmissioncell， which is then placed in the transmis-sion compartment of an instrument hav-ing sphere geometry.Typically， this type ofinstrument can also measure transmissionhazeand color. The haze value is related toturbidity for products such as clear juicesand brewed tea. Consistent product color， reducedwaste and improved customer satisfactionare some of the benefits of instrumentalfood color measurement. Use of proper in-strumentation and measurement protocolensures high precision and correlation tovisual perception. Hal Good is Director of Marketing at HunterLab. Reach himat 703-471-6870.m HunterLab Reston VA 703-471-6870 www.hunterlab.com Orange juice sample being prepared formeasurement using a"Ring and Disk"assembly.