Pelvic Suspension Research Articles

Animal Model of Simulated Microgravity: A comparative study of hindlimb unloading via tail vs. pelvic suspension

The aim of this study is to compare the effects of simulated microgravity in tail suspended (TS) as well as in pelvic suspended (PS) rats mimicking aspects of prolonged bed rest and sub‐clinical insulinopenia.Materials and MethodsAdult male Sprague‐Dawley rats divided into suspended and control‐non‐suspended groups (6 each per group), were subjected to two separate methods of suspension and maintained with regular food and water for two weeks. Body weights, food and water consumption, soleus muscle weights, malodialdehyde levels of soleus muscle and brain tissues were measured. Pressure‐pain threshold (PPT) was measured using Randall‐Selitto technique at regular 2–3 days intervals during one week before and 2 weeks after HLS.ResultsBody weights in suspended rats from day 10 are significantly different between groups. Food and water intakes are not different between control and suspended groups. Suspended rats had smaller soleus muscle weights and increased MDA levels (p <0.05). PPT were decreased below control after 5 days of PS and 10 days of TS and continued to drop till day 14. X‐ray images show less spinal deformity in PS rats as compared to TS rats.ConclusionsThese data suggest that both procedures develop peripheral neuropathy. Pelvic suspension appears to provide a suitable alternative to tail suspension for chronic hindlimb unloading alleviating excess stress.

Improving meat quality of organic pork through post mortem handling of carcasses: An innovative approach

This study was conducted to examine the best combination of post mortem chilling, suspension and ageing in order to optimize tenderness of organic pork at slaughter, which may be tougher than conventionally produced pork, because of lower daily gain. Combinations of stepwise chilling with a holding period of 6h at 10°C or traditional blast tunnel chilling, suspension in the pelvic bone or Achilles Tendon and ageing 2 or 4days post mortem were tested. Stepwise chilling and ageing improved tenderness of the loin, and the effects were additive, whereas pelvic suspension was less effective in texture improvements, and non-additive to stepwise chilling. Stepwise chilling improved tenderness to a similar degree as can be obtained within 2–4days of extended ageing, however, the minimum temperature during the holding period seems to be crucial in order to obtain a positive effect of stepwise chilling, and it should be above 7.5°C.

Influence of slaughter age and carcass suspension on meat quality in Angus heifers

This study investigated the effects of pelvic suspension and slaughter age on longissimus thoracis et lumborum (LTL) from 40 heifers with at least 75% Angus breeding. A total of 20 heifers were slaughtered directly from pasture at 18 months of age, and carcass sides were hung either by the Achilles tendon or the pelvic bone. The other 20 heifers were assigned to an additional winter housing period and slaughtered at 22 months of age; carcass sides were hung only by Achilles suspension. All carcasses were electrically stimulated and assessed according to the EUROP carcass classification system. In addition, the LTL muscles were aged for 7 or 14 days before meat quality was evaluated for intramuscular fat (IMF), drip loss, colour, shear force, compression and sensory analysis. The 22-month-old heifers were heavier, fatter and had more IMF than 18-month-old heifers. Conformation scores (muscling) did not differ between the two slaughter groups. Pelvic suspension reduced both between- and within-animal variation for peak force, total energy and compression peak force. For the 18-month-old heifers, pelvic suspension also decreased peak force, total energy and compression variables for the LTL muscles from both ageing periods, whereas Achilles-suspended samples had lower shear force values only at day 14. Sensory analysis showed that pelvic-suspended sides had greater tenderness, lower bite resistance, less threadiness, higher juiciness and meat flavour and less visible marbling than meat from Achilles-suspended sides. Pelvic-suspended sides at 18 months of age were similar in peak force and total energy values to the 22-month-old heifers. The importance of ageing the Achilles-suspended sides was more obvious for samples from 18-month-old heifers than from the 22-month-old animals. The correlations between the different instrumental measurements and sensory tenderness were considerably higher for carcasses suspended by the Achilles tendon (r = −0.55 to 0.20) than for those hung by the pelvic bone (r = −0.25 to 0.19). More correlations between sensory-evaluated tenderness and shear variables were significant after 7 days (n = 6) of ageing than after 14 days (n = 4) of ageing. This study clearly shows the benefits of pelvic suspension, which reduces the need for additional feeding after pasture.

Does carcass suspension technique influence reindeer (Rangifer tarandus tarandus) meat quality attributes?

In total, eight reindeer steers (ages 3–6 years old) were used in the study to evaluate the effects of carcass suspension technique on meat tenderness, colour and water-holding capacity (WHC). Carcasses were split along the spine and sides were randomly allocated to pelvic suspension (hung using a butcher hook through the obturator foramen) or normal Achilles tendon suspension (control treatment). From all 16 carcass halves, meat samples were collected from the loin (M. longissimus), inside (M. semimembranosus) and shoulder (M. triceps brachii) for sensory evaluation and measurements of shear force (tenderness). Loin samples were also evaluated for meat colour at 1 day after slaughter and for purge (WHC) after vacuum-packaged chilled storage (+2°C) for 1, 2 and 3 weeks. No significant effects of carcass suspension technique were found for reindeer meat colour and WHC (purge). Shear force values for loin samples from pelvic-suspended carcasses were significantly (P = 0.001) lower than those from Achilles tendon-suspended carcasses, and there was a similar trend for inside samples, although this was not significant (P = 0.06). There was no effect of carcass suspension technique for shear force values of the shoulder samples. The trained panel judged loin and inside samples from pelvic-suspended carcasses to be more tender (P ≤ 0.001) while no effect of carcass suspension technique on tenderness was found in the shoulder samples. Juiciness was not affected by carcass suspension. The present study demonstrated that pelvic suspension improved tenderness in the most valuable cuts from the reindeer carcass (loin and inside).

Effects of pelvic suspension of beef carcasses on quality and physical traits of five muscles from four gender–age groups

Pelvic and Achilles suspension methods for beef carcasses were compared for four gender–age groups (24month bulls, 34month bulls, heifers, and cows) and five muscles [M. longissimus dorsi (LD), M. semimembranosus (SM), M. adductor (AD), M. psoas major (PM), and M. gluteus medius (GM)]. Pelvic suspension increased muscle and sarcomere lengths in the SM, LD, GM, and AD muscles. The following effects were significant (p<0.05). Peak force was reduced by pelvic suspension in the LD and GM of bulls-24 and bulls-34, but not heifers and cows. Furthermore, peak forces decreased for the SM after pelvic suspension in bulls-24, bulls-34, and heifers. For the AD, the only decrease in peak force was for bulls-34. Water-holding capacity increased and purge in vacuum bags decreased for pelvic suspension of all muscles except the PM. Although the effects of pelvic suspension varied somewhat between gender–age groups and muscles, this method of hanging carcasses merits industrial consideration because it improves muscle yields, tenderness, and reduces variation within muscles.

Patents for Stretching and Shaping Meats

Attempts over the years to speed up the slaughter and processing of meat have been limited by the impact on important meat quality traits, such as tenderness. A number of methods and equipment have been developed for stretching and/or shaping to enhance the tenderness of meat, reducing the need for long term storage and ageing of meat. The more successful methods and equipment to improve the tenderness of meat - Tenderstretch (pelvic suspension), Tendercut (skeletal separation), SmartStretch™/Smartshape™ and Tenderbound (Pi-Vac Elasto-Pack system) are the subject of this review. Minimal research has been performed to compare these methods of tenderising meat. Tenderstretch and Tendercut are relatively easy to implement and require no specialised equipment, but they are relatively inflexible and only impact on a small number of muscles. The adoption of Tenderstretch has also been limited by increased resource requirements (chiller space and labour). SmartStretch™/Smartshape™ and Tenderbound, which wrap hot-boned pre-rigor muscles to prevent muscle contraction and shortening during rigor, are systems that do require specialised equipment. The major advantage of these systems is that they are very flexible and can be applied to any target muscle. Further research needs to be undertaken to compare these methods to better facilitate their commercial adoption. The article presents some promising patents on stretching and shaping meats.

Consumer evaluation of venison sensory quality: Effects of sex, body condition score and carcase suspension method

Intact fallow bucks (n=20) and non-pregnant fallow does (n=24) (Dama dama), in the body condition score (BCS) of 2, 3 and 4 (lean, prime and fat) and rising 2 year old red deer stags (n=26) (Cervus elaphus) of the same BCS range (2-4) were used in this study to determine the impact of sex, BCS and method of carcase suspension on consumer perception of venison quality. Consumers were asked to evaluate cooked meat samples (M. gluteus medius) on an unstructured line scale for colour, flavour, tenderness, juiciness and overall liking. Meat from both fallow deer and red deer was preferred by consumers when carcases had hung by the pelvic suspension (PS) method compared with the Achilles tendon (AT) method of hanging (p<0.001). Consumers also noted a difference in colour between sexes in fallow deer venison, with venison from 36 month-old does being darker (p=0.015), and preferred venison from does over 18-24 month-old bucks. There was a significant difference in the consumer scores for tenderness in red deer stags of BCSs 2 and 4 (p=0.05) with panellists determining BCS 4 animals to be more tender; however no tenderness differences were observed for fallow deer does compared with bucks.

Potential of nuclear magnetic resonance spectroscopy to measure biochemical changes during post mortem aging of beef hung by Achilles or pelvic suspension prior to rigor

Potential of nuclear magnetic resonance spectroscopy to measure biochemical changes during post mortem aging of beef hung by Achilles or pelvic suspension prior to rigor

Influence of carcass suspension on meat quality of Charolais heifers from two sustainable feeding regimes

This study investigated the effects of pelvic suspension on the meat quality of M. longissimus dorsi, M. semimembranosus and M. adductor from 35 heifers with at least 75% Charolais breeding. Two-thirds of the heifers were slaughtered directly from pasture at 18 months of age and one-third was finished indoors and slaughtered at 22 months. After slaughter and electrical stimulation one side of each carcass was re-suspended by either the achilles tendon or the pelvic bone. Longissimus muscles were aged 7 or 14 days and were then evaluated for drip loss, colour, shear force and sensory analysis. As compared to 18-month-old heifers, 22-month-old heifers were heavier, more muscular and fatter (P < 0.05). Intramuscular fat content increased with slaughter age (P < 0.003). Pelvic suspension reduced longissimus peak force values, total energy, pH and thawing losses (P < 0.05) in heifers slaughtered at 18 months. Semimembranosus showed the largest response to pelvic suspension with significantly lower peak force and total energy values. Finishing for 4 months did not affect longissimus shear forces. Achilles-suspended samples had lower shear force values after 14 v. 7 days of ageing. Pelvic-suspended samples aged 7 days were, however, just as tender as those aged 14 days. Sensory analysis of longissimus samples aged 14 days showed that samples from pelvic-suspended sides had higher tenderness, lower bite resistance, more meaty taste and less visible marbling compared with samples from achilles-suspended carcasses.

Comparison among some tenderization processing on Maremmana meat

Tenderness is the most important characteristic to define acceptability of products by consumers. In this paper three different methods, Calcium infusion (Ca), Very Fast Chilling (VFC) and pelvic suspension hanging from aitch bone (PS) or the Achilles tendon (AT) are applied in pre-rigor phase on Maremmana meat. Ca injection has reported the lowest shear force on cooked meat compared to control group (5.09 vs. 16.33 kg instead VFC group has underlined intermediate values. Pelvic hanging has shown significant difference on shear force and sarcomere length on Longissimus thoracis muscle (4.13 vs. 8.11 kg and 1.63 and 2.04 µm respectively for WBS and sarcomere length in PS and AT); further in Biceps femoralis we have found a lowest collagen content (4.33 vs. 4.79 g/100 g for PS and AT). In conclusion these methods could influence tenderization processes even if some processes, that could lower the effect of these practices, are still unclear.)

Pelvic suspension and fast post-mortem chilling: Effects on technological and sensory quality of pork – A combined NMR and sensory study

The effects of pre-rigor excision, which results in a fast post-mortem chilling; pelvic suspension, which results in a muscular stretching; control treatment of m. longissimus dorsi on water distribution measured by 1H NMR relaxometry and on sensory properties were investigated in two sub-studies including a total of 16 pigs. Determination of sarcomere length revealed significant effects of the treatments on the degree of contraction, as pre-rigor excision and pelvic suspension resulted in shorter and longer sarcomere length, respectively. In addition, an effect of treatment on pH measured at 24 h post-mortem was found, as pre-rigor excision was associated with a higher ultimate pH. NMR measurements revealed that water distribution in the meat was affected to a minor degree by the various treatments. However, an interaction between treatment and ageing period was observed, as the data demonstrated an effect of pre-rigor excision on water distribution in the cooked samples when meat was only aged for 2 days, but this effect was eliminated when meat was aged for 5 days. The effect of pre-rigor excision on water distribution in cooked meat after 2 days of ageing is suggested to reflect structural constraints in the meat that are eliminated during ageing. Sensory analyses demonstrated strong interactions between treatment and position on the muscle and between treatment and ageing period. However, in general pre-rigor-excised meat was sensed as significantly juicier compared with the other two treatments. Accordingly, the study demonstrates that under the present conditions the ultimate pH is more important for juiciness than the sarcomere length.

Pelvic suspension improves quality characteristics in M. semimembranosus from Swedish dual purpose young bulls

To study whether pelvic suspension would improve tenderness in comparison with normal hanging from the achilles tendon, carcasses from 34 Swedish red and white young bulls were randomly selected at the slaughter line. The left sides of the carcasses were re-hanged by the pelvic bone before cooling whereas the right sides remained hanging from the achilles tendon. Quality characteristics and length and weight were studied for M. semimembranosus. Tenderness was measured by the Warner-Bratzler shear force method. Purge and cooking loss were determined and sarcomere length was measured. Pelvic suspension considerably affected the shape of M. semimembranosus; the length increased by 38% in comparison with achilles suspension. The elongation of the muscle was parallel with an increase in sarcomere length from 1.6 to 2.9 μm. The water-holding capacity was improved because both purge and cooking loss were lower for pelvic suspended carcasses. Tenderness was improved and the coefficient of variation between animals for Warner-Bratzler shear force was reduced from 26% for achilles tendon suspension to 12% for pelvic suspension. Likewise, the within-animal variation for shear force decreased significantly from 13.3% to 10.0%. Therefore, pelvic suspension seems to be a reliable method to reduce texture variability in M. semimembranosus from young bulls.

Carcass treatments for improved meat quality (In Swedish with Summary in English)

Meat quality is a term that includes many different aspects like e.g. safety, ethics, nutrition, taste and functionality. What is regarded as most important is mainly related to where a person is placed in the chain from production to consumption. Along this chain are also many factors that influence the quality of meat. By measuring the pH value of meat it is possible to get good information about shelf life, tenderness, colour and water-holding capacity. Meat pH also gives an indication to whether the animals have been exposed to stress prior to slaughter or not. Good pastures and supplementary feeding using grain-based feed mixtures have been demonstrated to increase the energy stores in the animals' muscles and therefore have a positive effect on pH values in venison. What the animals had been eating prior to slaughter also affected the fat composition and meat flavour. Meat from animals grazing pasture had more polyunsaturated fatty acids and a "wild" flavour compared with meat from animals fed grain-based pellets. It is possible to change the fat composition in a commercial grain-based feed mixture, without altering the protein or energy content, so that the fat composition mimic that of a natural pasture. Pelvic suspension of a carcass will stretch the muscles in valuable cuts and improve the tenderness of the meat. In fallow deer carcasses the tenderness was improved in several meat cuts and in addition the water-holding capacity of the meat increased after pelvic suspension. Electrical stimulation of the carcass quickly empties the energy stores in the muscles and accelerates the onset of rigor mortis. In red deer venison electrical stimulation accelerated the rate of meat tenderisation, but this benefit was lost after approx. 3 weeks of ageing (-1.5 °C). A study from Alaska demonstrated no effects of electrical stimulation of reindeer carcasses on meat tenderness or water-holding capacity. We recommend further studies of pelvic suspension and electrical stimulation to get a better understanding of their effects on venison quality and to be able to implement these techniques in the most optimal way.

EXternal Pelvic REctal SuSpension (Express procedure) for rectal intussusception, with and without rectocele repair

The results of conventional treatment for rectal intussusception and rectocele are unpredictable. The aim was to develop a less invasive surgical approach and to evaluate outcome in selected patients. Seventeen patients (13 women; median age 47 (range 20-67) years) with rectal evacuatory dysfunction and rectal intussusception, 13 of whom had a rectocele, were selected. The intussusception was corrected by external pelvic suspension of the rectum, using collagen strips attached to the rectal wall and pubis. The rectocele was repaired with a collagen patch. Patients were assessed before and 6 months after surgery by symptom and quality of life questionnaires, anorectal physiological investigation and proctography, and were followed up for a median of 12 months. Sepsis requiring exploration occurred in two patients but there was no extrusion or need to remove the collagen. Of the 15 patients assessed after surgery, total symptom scores were significantly decreased (P < 0.001) and quality of life scores improved (P < 0.001). Proctographically, the degree of intussusception was improved in ten patients; six patients had normal postoperative proctograms. The rectocele was reduced in size in all patients, and was not demonstrable in eight. An effective procedure for rectal intussusception and rectocele has been developed in a selected group of patients with marked evacuatory symptoms.

Effect of pelvic suspension and cooking method on the processing and sensory properties of hams prepared from two pork muscles

The effect of two hanging methods (Achilles and aitch-bone) and two cooking methods (normal and Delta-T (ΔT)) on the quality of cooked hams produced from two muscles, M. semimembranosus (topside) and M. biceps femoris (silverside) was examined. Pork sides were hung by the Achilles tendon (conventional) or the aitch-bone (pelvic suspension) 1 h post-slaughter and chilled for 24 h at 1 °C. The hams were steam-cooked using a ‘normal’ cooking cycle (cooked at 85 °C to a core temperature of 72 °C) or a ‘ΔT’ cycle (maintaining a constant difference, of 35 °C, between oven and core temperatures until the oven reaches 85 °C, whereupon the core is allowed to come up to 72 °C). Pelvic suspension increased (P⩽0.01) the brine uptake of silverside hams, by 2.6%, but not of topside. The ΔT cooking method had a significant effect (P⩽0.05) for both muscles, reducing cook losses by 2.3% units in the topside hams and 3.3% in the silverside hams, compared to the normal continuous cook. Pelvic suspension resulted in slightly (P⩽0.05) more tender and juicy hams from silverside but not from topside. Both hanging method (Achilles and Aitch-bone) and cooking method (normal and ΔT) affected silverside ham more than topside ham. The overall result was that a combination of pelvic suspension and ΔT cooking had a positive effect on the quality of cooked hams, particularly hams produced from the silverside.

Sensory and meat quality traits of pork in relation to post-slaughter treatment and RN genotype

The effects on eating quality and meat quality of two different forms of post-slaughter treatment, performed in an abattoir, were studied in carriers and non-carriers of the RN − allele. Carcasses were subjected to rapid and slow chilling, and pelvic and Achilles suspension in a factorial experimental design. A temperature of 10 °C was achieved in the centre of M. longissimus dorsi (LD) within 3.5 h in rapidly chilled carcasses and within 8 h in slowly chilled carcasses. In deep M. semimembranosus (SM) a temperature of 10 °C was achieved within 11.5 h in rapidly chilled carcasses and within 14 h in slowly chilled carcasses. LD from slowly chilled RN − carriers suspended by the pelvis exhibited the greatest tenderness, while LD from rapidly chilled non-carriers suspended from the Achilles tendon exhibited the lowest tenderness. Pelvic suspension or slow chilling of non-carriers produced the same improvement in tenderness, and when combined the tenderness increased further. However, the tenderness of the RN − carriers was already high, and no significant improvement was seen following any of the studied post-slaughter treatments. Pelvic suspension prevented shortening of muscle fibres, as seen by longer sarcomeres in LD from pelvic-suspended sides. However, longer sarcomeres were associated with greater tenderness only in LD from non-carriers of the RN − allele. The presence of the RN − allele and a slow chilling regime increased the rate of pH decline in LD. Achilles suspension also increased the rate of pH fall in SM, in addition to the RN − allele and slow chilling. The overall tenderness of LD was mainly related to the course of pH decline during rigor; lower pH values between 3 and 7 h post-mortem contributing to greater tenderness. The myofibrillar length was predominantly related to RN genotype and was shorter in RN − carriers than in non-carriers. The RN − allele and slow chilling contributed to higher evaporation losses and RN − carriers exhibited increased frequency of PSE meat in the ham muscles. The use of pelvic suspension appears advantageous over slower chilling, since it improved tenderness without any negative influence on drip loss, evaporation or cooking loss.

The influence of the rate of pH decline on the rate of ageing for pork. I: interaction with method of suspension

The influence of the rate of pH decline post slaughter on the rate of ageing of pork was investigated. The rate of pH decline on 24 finisher pigs was manipulated by altering the method of stunning (carbon dioxide or electrical head to heart) and by the use of electrical stimulation (none or low voltage electrical stimulation (LVES) at 4 min post slaughter). To investigate the effect of pH decline rate on ageing rate independently of the effect on possible muscle shortening, sides were suspended by either the pelvis (to minimize shortening) or conventionally by the Achilles tendon. The data indicated that the rate of pH decline did not influence the rate of ageing but the use of LVES did improve tenderness at 1, 2 and 10 days post slaughter due to the prevention of muscle shortening. Electrical stunning improved tenderness at 1 and 2 days post-slaughter but had a detrimental effect on drip loss. Pelvic suspension improved tenderness at rigor, 1, 2 and 6 days post slaughter due to prevention of muscle shortening. The conditions employed however were not severe enough to induce protein denaturation.

Effect of pelvic suspension on three major leg muscles in the pig carcass and implications for ham manufacture

Thirty-two female pigs were slaughtered and their left sides suspended conventionally by the Achilles tendon whilst right sides were suspended from the pelvic bone. The first 16 pigs were used to measure suspension effects on the characteristics of three major leg muscles ( m. gluteobiceps, m. semimembranosus and m. rectus femoris) and to assess their suitability for ham manufacture. The remaining pigs were used for the production of hams, made from tunnel- boned whole legs injected to a target 10% weight gain, then tumbled and cooked. Compared with conventional hanging, pelvic suspension resulted in significantly ( P<0.01) lower weight loss from the sides during chilling (2.8 and 2.5%). There were major changes in the shape of all three muscles, with pelvic suspension producing marked increases in the width of the m. gluteobiceps (24%) and length of the m. semimembranosus (34%), and a small reduction in the length of the m. rectus femoris (2%). It also resulted in the two former muscles having a relatively higher brine retention, lower drip losses after storage and lower instrumental texture values (Volodkevitch shear force). Cooking loss was reduced in the pelvic-suspended m. semimembranosus. Similarly, whole gammon hams made from pelvic-suspended sides had greater injection gains than hams from conventionally-hung sides (13.6 and 12.3%), with lower cooking losses (16.7 and 19.0%). Instrumental texture values (punch and die peak force) made on the individual muscles in 3-mm thick slices were lower for the m. gluteobiceps (5914 and 9085 g) and m. semimembranosus (6163 and 7600 g) as a result of pelvic suspension. There were minor but significant effects on some colour parameters which probably have little commercial impact. The results demonstrate the advantages of pelvic suspension in terms of brine uptake and retention, and hence increased yield, as well as reduced toughness, for at least two of the major leg muscles, m. gluteobiceps and m. semimembranosus, with no disadvantage for the m. rectus femoris. Together, these three muscles constitute about half of the trimmed leg weight.

Effect of pelvic suspension and cooking temperature on the tenderness of electrically stimulated and aged beef, assessed with shear and compression tests

Electrically stimulated carcass sides of young bulls were suspended at 1 hr post mortem from the aitch bone (pelvic suspension; PS) and Achilles tendon (AT), respectively. After an ageing period of 14 days at 3 °C, shear force (SF) and compression (20 and 80% compression) tests of the Mm. longissimus lumborum et thoracis (LO) and semimembranosus (SM) were conducted in raw muscle and after heating for 1 hr at 55, 60, 65, 70 and 80 °C. Collagen content was higher in SM than in LO, while sarcomere length (SL) of raw muscle were 1.75 and 1.78, for LO and SM. In comparison with the AT-side, PS increased SL by 21 and 47% and cooking loss (at 80 °C) by 2 and 6% for LO and SM, respectively. Drip loss of whole muscles from the PS-side during the ageing period tended to be lower (n.s.). Over the whole cooking temperature range, SF-values were relatively high for the SM in comparison with LO. For both muscles from the AT-side, the lowest SF-values were observed at 60 and 65 °C. The PS-treatment resulted in higher SF- values for raw muscle and after cooking at low temperatures (55 and 60 °C), particularly in the SM. In the intermediate temperature range (65 and 70 °C), PS had no significant effect, while in the higher temperature range (80 °C), SF-values were lower in the PS-side. Similar tendencies were observed in the LO, although the lower SF-values for the PS-side were observed already at 60 °C. In non-destructive compression (20%), there was a gradual increase in stress values with increasing cooking temperature. In comparison with the AT-side, the PS treatment resulted in the LO in similar or higher, and in the SM in lower stress values. With destructive compression (80%), PS resulted in SM in higher stress values in raw muscle and at 55 °C, in accordance with the SF-values. It is suggested that the higher SF- and 80% compression values in raw muscle and at low cooking temperatures, are caused by an increase in collagen strength due to a change in the direction and spatial organisation of the collagen fibres as a result of stretching of the muscle. This study demonstrates that the relative contributions of the collagen and myofibrillar components to the mechanical assessed toughness, as well as the effect of pelvic suspension, is dependent of muscle, cooking temperature and the mechanical test applied.

Improving pork quality by electricalstimulation or pelvic suspension ofcarcasses

This investigation compared the separate and combined effects on meat quality of electrical stimulation (ES) and pelvic suspension of pig carcasses chilled rapidly or conventionally. Sides from 80 pigs, 80–90 kg live weight, were allocated to one of four treatments followed by either conventional chilling (1°C for 24 h) or rapid chilling (-20°C for 2–3 h, before 1°C until 24 h post-slaughter). The four treatments were: Achilles suspended, with and without high voltage ES, and pelvic suspended, with and without ES. The quality attributes: pH, colour and opacity, drip loss, instrumental and sensory texture were measured in M. longissimus thoracis et lumborum, at 10 days post-slaughter. Rapid chilling reduced the evaporative weight loss by 0·5% There were no significant effects of treatment on colour or opacity, although ES samples were slightly paler. Drip loss was also slightly greater with ES, particularly when combined with pelvic suspension, but in no case was the meat classified as PSE. Instrumental measurements of 'texture showed improved tenderness from both ES and pelvic suspension, even after 10 days ageing. The improvement was less pronounced when ES and pelvic suspension were combined Taste panelling confirmed that samples treated by ES or pelvic suspension, separately or combined, were significantly more tender than samples from non-ES, Achilles hung sides. ES and pelvic suspension were equally effective in improving the tenderness of pork loin. Pelvic suspension did not suffer the disadvantage of increased drip loss that occurred with ES in this study.