Comparison of objective measures of pork colour traits during ageing of the longissimus muscle from pigs housed organically and conventionally

Abstract

Pigs raised conventionally (n = 56) and indoors organically (n = 47) from different three-way crossbred genotypes were used to assess the capacity of pork colour attributes during ageing to discriminate between two methods of rearing pigs. Instrumental colour characteristics were measured on L. thoracis muscle from day 1 to 7 of storage, and the relative contents of metmyoglobin (MMb) and oxymyoglobin (MbO2) were estimated. The yellowness and chroma indices were lower in conventional than organic pork at all sampling times except on day 3 of storage. Lightness and hue angle were lower, whereas redness index was greater, in conventional than organic pork during all days of storage. Using MMb rather than MbO2 could be useful to highlight myoglobin oxidation in pork meat because it was weakly correlated with the measured CIELab colour attributes. Despite the differences in instrumental colour attributes, discrimination between conventional and organic (not free-ranging) pig husbandry was not possible. However, 3 days of storage combined the best colour (low hue angle and high redness index) and haeminic pigment balance (low MMb and high MbO2).