The Effect of Stunning Methods on Rigor Mortis and Texture Properties of Atlantic Salmon (Salmo Salar)

Shear force and rigor mortis were used to evaluate the post‐mortem changes of muscle texture in Atlantic salmon (Salmo salar). The fish were either stunned with carbon dioxide (CO₂), electricity, or percussion prior to slaughter. The pre‐mortem stress during CO₂ stunning resulted in an earlier onset and resolution of rigor mortis, and accelerated post‐mortem softening of the muscle tissue as compared to the other stunning methods. No significant differences, either in development of rigor mortis or shear force, were seen between fish that were stunned with electricity or by percussion. Consequently electricity can be used for stunning fish prior to slaughter.     

Design, Modeling, and Verification of High-Performance AC–DC Current Shunts From Inexpensive Components

A new type of AC current shunt for AC-DC current transfer is presented for which the AC-DC current differences at frequencies from 10 to 100 kHz are calculated with uncertainties smaller than plusmn 9 muA/A in the current range of 30 mA-10 A. This is an independent realization of the AC-DC current-transfer standards in addition to the step-up method used at most National Metrology Institutes. The construction, modeling, and experimental verification of the shunts are described.     

Studies on the palmitoyl-CoA hydrolase activity in carrot

Carrot homogenate contains a palmitoyl-CoA hydrolase. The enzyme was detected by spectrophotometric and radiochemical methods. The activation energy (Ea) for the reaction was determined to be 16700±2000 cal mol^?1 with a Q10 of 1.8. The rate of reaction reaches its maximum at 45°C and ceases completely at 55°C. The inactivation energy was found to be 67000±11000 cal mol^?1. A purification factor of 60 was obtained when polyvinylpyrolidone, polyethylene glycol, dithiothreitol and glycerol were used as stabilising agents, and the purification of palmitoyl-CoA hydrolase was carried out without delay. The method used successively, polyethylene glycol fractionation and DEAE-cellulose, hydroxylapatite and Ultrogel AcA 34 chromatography. Palmitoyl-CoA hydrolase has a molecular weight of 42000 daltons and a pI of 4.6. The role of this enzyme in the development of off-flavour in carrot has been discussed.     

Comparison EUROMET.EM-K8 of DC voltage ratio: results

A regional key comparison of dc voltage ratio has been carried out in Europe. The method to evaluate the comparison reference value, the resulting degrees of equivalence for the voltage ratios 1000 V/10 V and 100 V/10 V and the link to the corresponding worldwide key comparison CCEM-K8 are reported.     

Peroxidase,catalase and palmitoyl-CoA hydrolase activity in blanched carrot cubes after storage at −20°C

The effect of storage at ? 20°C was studied on carrot cubes which had been blanched at 50°, 60°, 70° and 80°C for 2, 5, 10 and 20 min. A sample of unblanched carrot cube was used as reference. Results from sensory methods were compared with the activity of the three enzymes, palmitoyl-CoA hydrolase, catalase and peroxidase. Good quality retention was obtained when palmitoyl-CoA hydrolase was no longer present, while activity of catalase (9%) and peroxidase (6%) remained.     

Oxygen consumption rate of permeabilized cells and isolated mitochondria from pork M. masseter and liver examined fresh and after freeze-thawing at different pH values

Abstract: The oxygen consumption rate (OCR) of 2 types of permeabilized tissues and their corresponding isolated mitochondria from porcine M. masseter and liver, resulting in 4 systems, was studied at different pH values (5.0 to 7.1) using fresh samples and samples frozen directly in liquid nitrogen (N₂) or air‐frozen at ?20°C. A protocol with the additive sequence rotenone–succinate–ADP (adenosine diphosphate)–cytochrome c–FCCP (carbonyl cyanide p‐trifluoromethoxyphenylhydrazone) was used to study respiration changes. The OCR of liver respiring on succinate (OCR _S ) was higher than that of muscle tissue. pH had a larger effect on OCR_S than freeze‐thawing. Low pH was associated with reduced OCR_S. The OCR_S of isolated muscle mitochondria appeared to be an underestimated relative to the OCR_S of permeabilized muscle cells. Increasing pH, following prior subjection to pH 5.0, showed partial reversibility of the OCR_S. The freeze‐thaw cycle increased the OCR_S when muscle systems were frozen and examined above pH 6.0; this effect was less apparent for liver tissue. A response to cytochrome c addition, indicating a defective outer mitochondrial membrane, was observed for all 4 systems. The response was, however, lowest for permeabilized cells. The ADP/FCCP additive pair indicated partial coupling for isolated liver and muscle mitochondria. These additives gave weak responses for the permeabilized liver cells while the OCR seemed to be inhibited for permeabilized muscle fibers when ADP/FCCP was added. Practical Application: The mitochondrial state is believed to be important for myoglobin reduction, development of flavor, and possibly other meat qualities. By monitoring the oxygen consumption in mitochondria and meat we can better understand and control such processes following freezing and thawing.     

Chemical composition of meat and blubber of the Cape fur seal (Arctocephalus pusillus pusillus)

Although the Cape fur seal is harvested commercially in southern Africa, no data exist to indicate whether its meat composition is such that it can be consumed by humans. Presently, these animals are harvested mainly for their hides. Little is known about the chemical composition of the meat and blubber and whether it could be processed into food or animal feed. This is the first report on the chemical composition of the Pectoralis muscle and fat of seal pups and bulls. The fat content in the muscle of pups was higher (4.2 g/100 g) than recorded in bulls (2.4 g/100 g). The protein content in muscle, on the other hand, was similar (23.2 g/100 g) for animals of both age groups. The blubber of bulls had a higher protein level (26.6 g/100 g) compared to that of pups (14.6 g/100 g), but a lower fat content (67.1 g/100 g vs 77.2 g/100 g). Muscle of bulls contained 33% saturated fatty acids (SFA), 29% monounsaturated fatty acids (MUFA) and 38% polyunsaturated fatty acids (PUFA). Muscle of pups contained 39% SFA, 30% MUFA and 31% PUFA. The toxin content in Cape fur seal blubber was lower than that reported for the blubber of Canadian seals. The organochlorine content in the blubber of Cape fur seals was lower than 13.7 ng/g oil, whereas levels as high as 87.2 ng/g have been reported in Canadian seal oil. The chemical composition of the Cape fur seal is such that it could be classified as a healthy meat source.     

Carbon Monoxide as a Colorant in Cooked or Fermented Sausages

ABSTRACT:  The study aimed at substituting nitrite with carbon monoxide (CO) in cooked or fermented meat batter products by investigating color and color stability in myoglobin solutions, model meat systems, and full-scale hotdog and salami sausages of pork and beef. For cooked model meat systems and hotdogs at 75 to 80 °C core temperatures, direct flushing with a 1% CO gas mixture during the last stage of the batter chopping produced an initial red color equal to nitrite or more intense than with nitrite. For fermented model meat systems and salami sausages with a final pH of 4.7, pretreatment and storage of ground raw meat in a 1% CO mixture, and later use of the pretreated meat in batters, also formed an initial red color in the final products. The color stability during air and light display of cooked and fermented meat products with CO was inadequate compared to products with nitrite, although the red color of CO products was largely maintained by anaerobic packaging and storage. Spectra of carboxy- and nitrosomyoglobin at pH 4.7 demonstrated higher absorbance for carboxymyoglobin.     

Z-disc digestion of isolated bovine myofibrils by an endogenous calcium activated neutral proteinase

Calcium activated neutral proteinase (CANP) activity has been purified from bovine M. semimembranosus. The effect of the enzyme on purified fractions of beef myofibrils is described. The Z-discs were the main target of the enzyme; small holes developed and the Z-discs were fragmented into smaller units of equal size. The Z-discs fragments were also split transversely, leaving half to each of the neighbouring sarcomeres. Prolonged digestion removed the entire Z-discs and its set of thin myofilaments. The functional importance of the proteinase in meat tenderization is discussed.