title: The effect of a muscle-glycogen-reducing finishing diet on porcine meat and fat colour.
abstract: The objective of the present study was to elucidate the significance of a muscle-glycogen-reducing finishing diet containing a high ratio of rapeseed and grass meal on fat colour and pork colour compared with a control diet. Pork colour was determined as the extent of blooming of M. longissimus dorsi (LD) and M. semimembranosus (SM) after 1, 2, 4, 8 and 15 days of aging, while fat colour was measured on back fat and stripped bacon the day after slaughter. The muscle-glycogen-reducing diet significantly decreased the glycogen content measured 1min after slaughter in LD. This was reflected as decrease in early post-mortem temperature, as well as a tendency to higher initial pH in both muscles. Moreover ultimate pH was significantly higher in LD from strategically fed pigs compared to the control group and the same tendency was found in SM. Independent of muscle and time of aging, the colour of bloomed pork from pigs fed the control diet had higher chroma and L(∗), a(∗) and b(∗) values compared with pork from the pigs fed the muscle-glycogen-reducing diet with the effect being most pronounced in LD. This can be explained by the slightly higher pH(45min) in the muscles from the pigs fed the muscle-glycogen-reducing finishing diet, which sustain the metmyoglobin reductase activity and the oxygen consumption potential in the muscle and hereby minimise the degree of blooming. The more pronounced influence of the experimental diet on the degree of blooming in LD compared to SM may be explained by the lower T(45min) in LD, which minimise denaturation of the enzymatic processes. This clearly shows that the diet composition can be used to control the extent of blooming in pork. Finally, despite the high content of grass meal in the muscle-glycogen-reducing finishing diet, this diet had negligible influence on the colour of the back fat and stripped bacon fat.
authors: Centre of Advanced Food Studies, Department of Food Science, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark.
authors: Kaja
authors: K
authors: Tikk
authors: Meelis
authors: M
authors: Tikk
authors: Anders H
authors: AH
authors: Karlsson
authors: Henrik J
authors: HJ
authors: Andersen