Lipolysis and lipid oxidation during chilled storage of meat from Large White and Pietrain pigs

The day after slaughter, six chops of Longissimus lumborum from each of 10 Large White pigs and six Piétrain pigs were packed individually under vacuum and kept at 3-4?°C in the dark. At 1, 5 and 9 days after slaughter, two chops were used for analysis of lipids, thiobarbituric acid reactive substances (TBARS), sarcoplasmic Ca(2+) and sarcoplasm and mitochondria phospholipase A(2) activity. Free fatty acid content was higher in Piétrains than in Large Whites and increased with keeping time. Total lipids of Large White pigs contained more saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) and less polyunsaturated fatty acid (PUFA). Large Whites had less dioleoyl-linoleyl-glycerol (OOL) and Palmitoyl-oleoyl-linoleyl-glycerol (POL) and more Palmitoyl-oleoyl-stearyl-glycerol (POS) than Piétrains. The percentages of SFA and MUFA decreased and the percentage of PUFA increased with time in FFA of Large White pigs. In Piétrains, similar changes were observed between days 1 and 5, but later the percentages of SFA increased and the percentage of PUFA decreased again. TBARS tended to increase with time particularly in Piétrains. Sarcoplasmic phospholipase A(2) decreased between days 5 and 9 in both breeds. Sarcoplasmic calcium was markedly higher at day 1 in Piétrains than in Large Whites then the difference decreased. These breed differences in lipid composition differences and lipid changes during storage are considered too small to be of practical importance, for instance in influencing the choice of a breed for pork production.     

Influence of intramuscular fat content on lipid composition,sensory qualities and consumer acceptability of cured cooked ham

The present study is part of a project which aims to examine the influence of intramuscular fat (IMF) content on the sensory attributes and consumer acceptability of pork. An experiment was conducted to evaluate the influence of IMF level in muscle semimembranosus (SM) on the composition of its lipid fraction and on the sensory qualities and consumer acceptability of cured cooked hams. Thirty‐two carcasses were selected 24 h after slaughter from 125 Duroc × Landrace castrated male pigs showing large variability in SM muscle IMF content and were assigned to four IMF groups: ≤2%, 2–3%, 3–4% and >4%. Cured cooked ham slices were evaluated by a trained expert panel of 12 members and by a group of 56 consumers. Results from lipid analyses indicate that (i) an increase in IMF content was almost entirely reflected by an increase in the triglyceride content of the muscle and (ii) higher IMF levels were associated with higher free fatty acid and monoglyceride and lower cholesterol levels. The sensory evaluation of marbling significantly increased with IMF level, whereas other sensory qualities were unaffected. High IMF levels significantly depreciated the consumer perception of fat, aspect, taste and smell of ham slices. Overall, slices with the highest IMF levels got the least favourable rating by consumers. The present study indicates that increased IMF levels in muscle semimembranosus do not have significant effects on the sensory attributes of cured cooked hams, apart from the perception of marbling. However, high IMF levels have detrimental effects on the acceptability by consumers. © 2000 Society of Chemical Industry     

Example of the enrichment of carbon-13 in coals in the process of coalification

δ13 C measurements on a series of coals from the Mahakam delta (Kalimantan, Indonesia) show a progressive increase from ≈ ? 29.5% at the peat-lignite transition to ≈ ? 27.5% at a reflectance of R₀ ≈ 0.9. Given the very good homogeneity of the series, the shift is likely to be due to coalification. However, a coalification model based on this trend and the release of C0₂, H₂0 and CH₄ indicates δ13 C values of C0₂ which are very low as compared to currently accepted figures.     

Effectson carcass weight and meat quality of pigs dehaired by scalding or singering post-mortem

Two experiments were designed to compare the effects of two pig dehairing techniques. In the first experiment, 120 pigs were slaughtered in the same abattoir in five weekly sereis. One half of each series was dehaired by singeing (the usual technique in this abattoir), while the other half was dehaired in a scalding-dehairing combination. In the second experiment, 48 pigs were slaughtered in two series, one-half of each series in an abattoir practising singeing, the other half in an abattoir practising scalding. Temperature and pH were measured 30 min after slaughter in the longissimus lumborum. Meat quality was assessed the day after slaughter in various muscles. One ham was cured and cooked, while the other one was processed by dry-curing. In both experiments, carcass weights and yields were noticeably higher after singeing. Hams were heavier in singed carcasses, but their proportions in the carcasses were little or not at all affected by the dehairing technique. Proportions of loins, shoulders and bellies were similar with both dehairing techniques. The dehairing technique affected neither temperature nor rate of post-mortem pH fall. Meat quality as assessed on fresh meat was slightly better in singed carcasses. Weights of cooked ham and dry ham per side were higher in singed carcasses, due to the higher initial ham weight, but processing yields were not affected by the dehairing technique.     

Influence of temperature variation on the metabolism of pig muscle in situ and after excision

The experiment involved six halothane-positive (HP) and six halothane-negative (HN) pigs of about 100 kg liveweight. Under general anaesthesia the tibialis cranialis was exposed. The temperature of the muscle was maintained at either 35 or 40°C (in situ). The muscle was stimulated via the peroneal nerve at 0·1 Hz for 10 min then 1 Hz for 10 further min. Twitch contractions were recorded throughout the stimulation, after which the muscle was excised and split into two parts which were kept in paraffin oil at either 35 or 40°C (post-excision temperature) for 2 h. Samples were taken just before and after the 20 min stimulation period, and at 1 and 2 h after muscle excision for determination of pH and concentrations of PC, ATP, IMP, glycogen, G-6-P and lactate. As soon as one muscle was removed, the operation was repeated on the other leg. Both temperatures (35 and 40°C) were applied to each animal in a balanced design. However data were obtained from only 11 pigs at 40°C as one HP pig died accidentally at the beginning of the 40°C experiment. Halothane sensitivity influenced the pH value and the levels of PC, G-6-P and lactate of the muscle in situ (P < 0·01 in all cases). Temperature affected contrction time (P < 0·01). Both halothane sensitivity and Post-excision temperature affected the pH values and the levels of PC, ATP, IMP, G-6-P and lactate (P < 0·01 in all cases) in the excised muscle. By contrast, the in situ temperature treatments did not affect any of the muscle traits measured after excision. It was concluded that the effects of the various treatments on the rate of metabolism in the excised muscle were wholly explainable in terms of temperature from the time of excision, and that the in situ temperature treatments may not be responsible for the differences after excision.     

Lie algebraic canonical representations in nonlinear control systems

This paper is the applied counterpart to previous results [5] for linear-analytic control systems. It is mainly concerned with two canonical representations of the exponential type. They exhibit the Lie algebraic structure of the system in such a form that results on weak controllability are easily derived in an algebraic manner. The first representation is a single exponential of a canonical Lie series in Hall's basis of the Lie algebra of vector fields. The second one is a factorization in terms of simpler exponentials of Hall's basic vectors. Both of them exhibit, as canonical coefficients, an infinite set of characteristic parameters which are a minimal representation of the input paths, when no drift occurs in the system (or, equivalently, in the weak control case). The weak controllability theorem is easily derived from these results, in a purely algebraic way.     

X-Ray analysis of the stress-strain state of metallic powders in pressing

Translated from Poroshkovaya Metallurgiya, No. 11, pp. 6–9, November, 1990.     

Proving the Correctness of the Standardized Algorithm for ABR Conformance

Conformance control for ATM cells is based on a real-time reactive algorithm which delivers a value depending on inputs from the network. This value must always fit with a well defined theoretical value. We present here the correctness proof of the algorithm standardized for the ATM transfer capability called ABR. The proof turned out to produce a key argument during the standardization process of ABR.     

Surgical treatment by vitrectomy and autologous serum of 36 idiopathic macular holes

The release of motilin from an isolated preparation of pig duodenum has been studied. There different types of stimuli were applied: electrical nerve stimulation, intraarterially administered peptides, and instillation of test solutions into the lumen of the duodenum. Furthermore extracts of 20 different regions of the pig digestive system have been analyzed for motilin content. Analysis of the extracts only detected significant presence of motilin in the pig duodenum and jejunum (79 +/- 15 and 60 +/- 19 pmol/g). The stimulation experiments showed: (1) a significant noncholinergic depression of motilin release during electrical stimulation of the vagus nerve (nadir at 74 +/- 5% of baseline level; (2) a significant elevation of motilin release in response to intraarterially administered vasoactive intestinal peptide (VIP) (peak at 330 +/- 35% of baseline level), and (3) a significantly elevated motilin release in response to instillation of autologuous bile (peak at 170 +/- 16% of baseline level) and hydrochloric acid (peak at 196 +/- 42% of baseline level) into the duodenal lumen. In conclusion, luminal acidification and bile are important factors in stimulation of motilin release, whereas the vagally stimulated VIP release was insufficient to overcome the general inhibitory effect of vagus stimulation.     

New method for identifying finite degree Volterra series

In this paper, the identification of a class of nonlinear systems which admits input-output maps described by a finite degree Volterra series is considered. In actual fact, it appears that this class can model many important nonlinear multivariable processes not only in engineering, but also in biology, socio-economics, and ecology.To solve this identification problem, we propose a method based on local gradient search in a local parameterization of the state-space realization of finite degree Volterra series with infinite horizon. Using the local parameterization not only reduces the amount of the gradient calculations to the minimal value, but also overcomes the nonuniqueness problem of the optimal solution.Moreover, we propose a sequential projection method to provide an initial estimation of the parameters of finite degree Volterra series realization. This initial estimation is used to initialize the gradient search method.