Instrumental colour classification of veal carcasses.

Three experiments, involving over 56 000 veal carcasses, were carried out to develop a method for instrumental colour classification of veal carcasses at 45 min post mortem with the Minolta CR300. The method should produce results similar to those of the 10-point colour-system, which is currently in use in The Netherlands. In the first experiment, the colour of veal carcasses was visually assessed by three observers and instrumentally measured with two Minolta CR300 devices. The average of the results of the three observers and the two Minolta devices were used for discriminant analysis to analyse yield classification rules, which allowed to assignment of the carcasses to classes of the 10-point colour-system. Identical classifications for Minolta and observer were obtained for 63.2% of the carcasses. In the second and third experiment, the classification rules with the Minolta CR300 were used to predict the colour class. For the new samples, identical classification results were obtained for 50-55% of the carcasses. In 41-44% of the carcasses the classification results differed by less than one class. The results show that the Minolta CR300 is under practical conditions able to predict the 10-point colour classes and can be used for on-line colour classification in a slaughterhouse.

Histochemical characteristics in relation to meat quality properties in the Longissimus Lumborum of fast and lean growing lines of Large White pigs.

A selection experiment was carried out to study genetic and physiological factors influencing meat quality in lines of Large White pigs selected for lean (L) or fast (F) growth. Second and fourth generation pigs were used to determine effects on fibre type composition, fibre diameters and capillary density in the Longissimus Lumborum (LL). Significant differences in histochemical properties were found in the LL between L- and F-pigs, but only in the 4th generation. L-pigs had significantly less type I and more type IIB myofibres compared to F-pigs in both sexes. In both lines lower type I and higher type IIB percentages were determined in gilts compared with boars. Significant differences in meat quality properties between L- and F-pigs were found in the LL, but only in the 4th generation. The a* values were significantly higher in F- versus L-pigs and in boars versus gilts. L* values were not significantly different between lines. However, L* values were significantly lower in 4th versus 2nd generation pigs and in boars versus gilts. In conclusion, genetic selection on lean versus fast growth induces differences in fibre type composition of the LL. These differences become visible in the 4th generation, when a certain selection effect is achieved. Fibre type composition was influenced by the gender of the animal. Meat quality showed significant differences between lines in meat colour (a* value), but only in the 4th generation. Capillary density and fibre area between L- and F-lines showed minor differences, which could be explained by the differences in weight and age of the pigs of both lines.

Differences in quality characteristics of normal, PSE and DFD pork.

Differences in water-holding capacity, colour and tenderness/toughness were studied in 21 pork loins belonging to three quality categories, i.e. dark firm dry (DFD), normal and pale soft exudative (PSE). The division into the three groups was based upon the ultimate pH-values of the loins (< pH 5·5, pH 5·5-6·0, pH > 6·4). The PSE loins were characterized by a poor waterholding capacity, higher cooking loss and paler colour in contrast to the DFD category. The normal loins took an intermediate position. Neither sarcomere length, determined on fresh muscle tissue, nor Armour tenderometer values showed significant differences between the various quality categories. This was in contrast to the Warner-Bratzler (W-B) shear force values, determined on cooked loins, which had the lowest values in the DFD category. A strong relationship between the W-B values and the cooking losses was found. It was concluded that neither sarcomere length nor Armour tenderometer measurements were able to predict the shear force values of cooked pork loins.

The use of filter paper to estimate drip loss of porcine musculature.

Two simple, accurate, rapid and economical methods for determining variations in drip loss of lean, prepackaged, post-rigor porcine musculature during storage have been developed. Laboratory grade filter paper having a 45 mm diameter was placed on the cut surface of the muscle (after 10-15 minutes' exposure) and scored for wetness (0 to 5) within 3 s or weighed for fluid accumulation. The tests on 40 randomly selected longissimus muscles that appeared to represent 'normal' quality characteristics proved to be nearly perfectly and positively correlated to % 48 h drip loss. Statistically, the relationship was non-curvilinear and, when regression equations were used to predict drip losses on a separate group of 27 muscles having considerable variation in quality, the correlations between the predicted and actual values were nearly perfect (r = 0·97 for score and 0·95 for weight). These two methods have not been compared to other, more sophisticated, ones currently used, but the results of this investigation suggest that the two methods may be useful to the meat industry, especially for practical applications.