American Meat Science Association Guidelines for Meat Color Measurement

Abstract

Meat color is an important aspect of consumer’spurchase decisions regarding meat products. Perceived meat color results from the interaction of light, a detector(i.e. human eye), and numerous factors that are both intrinsic and extrinsic tothe muscle which influence the chemical state of myoglobin.  The complex nature of these interactions dictatesthat decisions regarding evaluations of meat color be made carefully, and thatinvestigators have a basic knowledge of the physical and chemical factorsaffecting their evaluations.  Theseguidelines were compiled to aid investigators in navigating the pitfalls ofmeat color evaluation and ensure the reporting of information needed forappropriate interpretation of the resulting data.  The guidelines provide an overview ofmyoglobin chemistry, the perception of meat color, in addition to details ofinstrumentation used in meat color evaluation. Moreover, these guidelines detail practical considerations for simulatedretail display studies and provide details of the most common laboratorytechniques used in meat color literature. Importantly, the guidelines indicate the information that should beincluded when reporting meat color research to aid in appropriateinterpretation.  Practical considerationsneeded for troubleshooting meat color problems in a commercial setting areincluded as well.  Investigators areencouraged to review the entire guidelines before designing and conducting meatcolor research.

Meat color and iridescence: Origin, analysis, and approaches to modulation

“…The hue angle indicates the hue of a color and is expressed in degrees: 0 • would be red, 90 • yellow, 180 • green, and 270 • blue. According to King et al (2023), the hue angle is very useful to indicate shifts in color over time and is thus well suited to follow discolorations. Chroma is an indicator for the saturation and therefore refers to the degree of vividness of a color.…”

“…As the color of meat is largely determined by the relative amounts of the three major pigments deoxymyoglobin, metmyoglobin, and oxymyoglobin, reflectance measurements and visible absorption characteristics can be used to detect the amount and chemical state of myoglobin (Warner, 2014). For example, the ratio or difference between the reflectance percentage at 630 and 580 nm (R630/R580) is a parameter for the redness of meat samples and is typically used to measure changes in fresh meat color during display (King et al, 2023). Karamucki et al (2017) reported high correlations between changes in the relative levels of metmyoglobin and color change based on the absorbance of wavelengths of 540 and 505 nm and concluded that these parameters for color changes are more useful in the assessment of pork quality than the redness Δa* and hue angle Δh • .…”

“…Mancini (2007) stated that a major obstacle to researchers interested in investigating factors affecting meat iridescence is the difficulty in quantification due to the strong angular dependence. King et al (2023) recommends a 6-point sensory scale for the evaluation of iridescence intensity and extent, and most of the studies on meat iridescence involved a sensory analysis (Kukowski et al, 2004;Lawrence et al, 2002;Realini et al, 2011;Ruedt et al, 2021a;Wang, 1991). However, a major drawback of sensory analysis is the variation of panelists' sensitivity to iridescence (Wang, 1991) and the lack of spectral and spatial characterization of iridescent colors that is of particular interest for the clarification of the structural origin and the physical mechanism of meat iridescence.…”

“…Beef meat cuts were more desired when illuminated with incandescent light because of the appealing red color whereas the meat appeared dark brown or dark red under a fluorescent or metal halide light source. According to the recommendations of the AMSA (American Meat Science Association), lighting should have the following characteristics: (i) color temperature of 2800 to 3500 K, (ii) color rendering index (CRI) of 80 to 90, (iii) light intensity of 1612.5 to 2152 lux at the meat surface, and (iv) lighting from above the displayed meat sample (King et al., 2023). Also, the viewing conditions must be standardized, as the observation angle can affect the appearance of color.…”

“…According to King et al. (2023), the hue angle is very useful to indicate shifts in color over time and is thus well suited to follow discolorations. Chroma is an indicator for the saturation and therefore refers to the degree of vividness of a color.…”