Browsing by Subject "Iridescence"

Now showing 1 - 2 of 2

Influence of muscle type and microstructure on iridescence in cooked, cured pork meat products
(2021) Ruedt, Chiara; Gibis, Monika; Weiss, Jochen
Microstructural factors associated with surface iridescence in cooked, cured pork products were investigated. Meat iridescence is a commonly observed physical phenomenon in raw meat and meat products that consist of intact mus- cle tissue. Since the purchase decision of consumers is mainly driven by the first impression of meat color and appearance, products showing colorful iri- descence may be rejected. Four different muscles (RF: M. rectus femoris, BF: M. biceps femoris, ST: M. semitendinosus, and LD: M. longissimus thoracis et lum- borum) were brine-injected, cooked, sliced, and iridescence was evaluated by digital image analysis and sensory analysis. Sarcomere lengths, fiber diameters, and surface microstructure were analyzed in iridescent and noniridescent sec- tions. Highest iridescence extent by image analysis was found in LD (37.3 ± 16.4%), and highest overall iridescence score (extent and intensity, 6.11 ± 1.78) was observed in BF. Sarcomere lengths did not differ significantly between iridescent (1.05 ± 0.09 µm LD) and noniridescent areas (1.08 ± 0.94 µm LD) within mus- cles (p > 0.05). Iridescent sections showed smooth and ordered surface structures with cross-sectioned myofibers, whereas in noniridescent sections, surfaces were more unstructured and myofibers obliquely cut. The results of the study indicate that the sarcomere length and fiber diameters may thus be only of minor impor- tance for the explanation of meat iridescence in cooked meat products and are rather related to multiple scattering and absorption effects on smaller structural entities such as the myofilament lattice or larger entities such as fiber bundles. Practical application: Iridescence can be a problem for the meat industry due to consumers concerns about green-iridescent colors in meat. The underlying mechanisms and structures have not yet been fully clarified, and thus no prac- tical solutions to eliminate iridescence have been found so far. This research presents new insights into the structural attributes that are interrelated with meat iridescence and shows that iridescence is rather influenced by cutting angle of muscle fibers and surface homogeneity than by muscle fiber diameters or sar- comere lengths. This should be considered by the industry when seeking for ways to reduce the potential problem of iridescence
Meat color and iridescence: Origin, analysis, and approaches to modulation
(2023) Ruedt, Chiara; Gibis, Monika; Weiss, Jochen
Meat color is an important aspect for the meat industry since it strongly determines the consumers’ perception of product quality and thereby significantly influences the purchase decision. Emergence of new vegan meat analogs has renewed interest in the fundamental aspects of meat color in order to replicate it. The appearance of meat is based on a complex interplay between the pigment‐based meat color from myoglobin and its chemical forms and light scattering from the muscle's microstructure. While myoglobin biochemistry and pigment‐based meat color have been extensively studied, research on the physicochemical contribution of light scattering to meat color and the special case of structural colors causing meat iridescence has received only little attention. Former review articles focused mostly on the biochemical or physical mechanisms rather than the interplay between them, in particular the role that structural colors play. While from an economic point of view, meat iridescence might be considered negligible, an enhanced understanding of the underlying mechanisms and the interactions of light with meat microstructures can improve our overall understanding of meat color. Therefore, this review discusses both biochemical and physicochemical aspects of meat color including the origin of structural colors, highlights new color measurement methodologies suitable to investigate color phenomena such as meat iridescence, and finally presents approaches to modulate meat color in terms of base composition, additives, and processing.