The influence of final conditions on meat colour in light lamb carcasses

Consumer visual appraisal and shelf life of leg chops from suckling kids raised with natural milk or milk replacer

BACKGROUND

The use of milk replacers to feed suckling kids could affect the shelf life and appearance of the meat. Leg chops were evaluated by consumers and the instrumental color was measured. A machine learning algorithm was used to relate them. The aim of this experiment was to study the shelf life of the meat of kids reared with dam's milk or milk replacers and to ascertain which illuminant and instrumental color variables are used by consumers as criteria to evaluate that visual appraisal.

RESULTS

Meat from kids reared with milk replacers was more valuable and had a longer shelf life than meat from kids reared with natural milk. Consumers used the color of the whole surface of the leg chop to assess the appearance of meat. Lightness and hue angle were the prime cues used to evaluate the appearance of meat.

CONCLUSION

Illuminant D65 was more useful for relating the visual appraisal with the instrumental color using a machine learning algorithm. The machine learning algorithms showed that the underlying rules used by consumers to evaluate the appearance of suckling kid meat are not at all linear and can be computationally schematized into a simple algorithm. © 2017 Society of Chemical Industry.

Instrumental meat quality characteristics associated with aged m. longissimus thoracis from the four Canadian beef quality grades

Canadian beef is quality graded to characterize the potential eating quality of the cooked product. Instrumental meat quality characteristics of 48 m. longissimus thoracis (LT, rib eye) from four Canadian beef grades (Canada A, AA, AAA, and Prime, n = 12) before and after an additional 14-d aging were compared using a split plot design with grade, aging, and their interaction as fixed sources of variation. Mean percentage intramuscular fat was greatest in Canada Prime muscle and least in Canada A and AA muscles (P < 0.0001), whereas mean percentage drip loss was lower in Canada Prime muscle than in muscle from all other grades (P = 0.0348). Canada Prime and AAA muscles were redder and yellower than muscles from other grades even after aging (P < 0.03), which may be associated with increased fat content and indicative of accelerated myoglobin oxidation and increased myoglobin oxygenation. Shear force was not different among the Canada grades, although the differences between Canada AA cooked beef LT and that of Canada Prime and AAA carcasses approached significance (P = 0.0993). Results indicated that Canada quality grades did not differentiate beef on cooked product tenderness, substantiating that muscle compositional characteristics alone define beef grade advantages.

Breed, slaughter weight and ageing time effects on physico-chemical characteristics of lamb meat

The effects of breed, slaughter weight and ageing time on the meat quality of the three most important Spanish breeds were considered. Two hundred and twenty-five lambs of Rasa Aragonesa-local meat breed-, Churra-local dairy breed- and Spanish Merino were used. Animals (75 of each breed) were slaughtered at three different live weights (10-12, 20-22 or 30-32 kg), and the meat was aged for 1, 2, 4, 8 or 16 days. The meat pH, colour, amount of haem pigments, intramuscular fat, moisture, hydroxyproline content and sarcomere length were measured at 24 h post-mortem. Meat texture was measured by compression after each ageing time. The pH of the samples ranged from 5.50 to 5.58. Meat colour varied with breed and slaughter weight (P⩽0.01), the M. longissimus thoracis was lighter in the youngest animals and in the Churra breed and redder in Merinos. Intramuscular fat increased and moisture decreased for heavier lambs. Differences in collagen were associated with breed (P⩽0.01); total and insoluble collagen contents were higher in the Churra breed. Sarcomere length was only slightly affected by slaughter weight. Meat from the Churra breed had the highest values at high levels of compression. Suckling lambs (10-12 kg) had greater myofibrillar toughness than heavier lambs and ageing strongly influenced myofibrillar tenderness.

Current research in meat color

This review surveyed recent literature focused on factors that affect myoglobin chemistry, meat color, pigment redox stability, and methodology used to evaluate these properties. The appearance of meat and meat products is a complex topic involving animal genetics, ante- and postmortem conditions, fundamental muscle chemistry, and many factors related to meat processing, packaging, distribution, storage, display, and final preparation for consumption. These factors vary globally, but the variables that affect basic pigment chemistry are reasonably consistent between countries. Essential for maximizing meat color life is an understanding of the combined effects of two fundamental muscle traits, oxygen consumption and metmyoglobin reduction. In the antemortem sector of research, meat color is being related to genomic quantitative loci, numerous pre-harvest nutritional regimens, and housing and harvest environment. Our knowledge of postmortem chilling and pH effects, atmospheres used for packaging, antimicrobial interventions, and quality and safety of cooked color are now more clearly defined. The etiology of bone discoloration is now available. New color measurement methodology, especially digital imaging techniques, and improved modifications to existing methodology are now available. Nevertheless, unanswered questions regarding meat color remain. Meat scientists should continue to develop novel ways of improving muscle color and color stability while also focusing on the basic principles of myoglobin chemistry.

Effects of crossbreeding on carcass and meat quality of Mexican lambs

Twenty hair (Pelibuey x Katadin x BlackBelly) and 20 wool (Rambouillet x Criollo) lambs were fattened in an intensive feeding system to reach 40kg body weight at ten months of age. The yield of lamb sides and back fat (51.9%, 2.5mm vs. 47.0%, 2.3mm) were greater in wool lambs. Meat pH was not different between phenotypes but meat temperature was higher during the first hours postmortem in wool lamb sides (27, 23, and 20, vs. 24, 20, and 17ºC). Protein content in meat from the neck (braquicephalic and esternocephalic muscles) and loin (Longissimus lumborum muscle) were higher in hair lambs (21.1 and 20.4 vs. 19.7 and 19.3 %), while moisture of the same muscles was higher in wool lambs (75.6 and 75.9 vs. 73.6 and 74.3%). Ash content was similar in both phenotypes, but palmitoleic acid was greater in hair lambs (2.9 and 2.7 vs. 2.7 and 2.5%). In fresh meat, pH, meat toughness, and water activity (Wa) of loin did not differ; but water holding capacity (WHC) was higher in hair lambs, and the same response was observed for cooked meat toughness from the neck, and in raw and cooked meat from loin. There were differences in the colour of meat from the neck, having values for L*, b* and tonalities greater in wool lambs, and a* greater for hair lambs. Sensorial parameters were similar in both phenotypes.