Porcine Longissimus Muscle Research Articles

Influence of Temperature, Fibre Diameter and Conditioning on the Mechanical Properties of Single Muscle Fibres Extended to Fracture

The tensile properties of single muscle fibres isolated from porcine longissimus and iliocostalis muscles conditioned for various lengths of time and cooked at different temperatures for 1 h were investigated. The stress-strain curves of fibres extended to fracture were r-shaped with yield points of 2-5% resting length in raw fibres and 10-20% in cooked fibres. The yield point was independent of cooking temperature, fibre diameter and mechanical skinning of the fibres but decreased with ageing. The stress and strain at which the muscle fibres fractured was found to depend on cooking temperature, fibre diameter and conditioning time. Raw muscle fibres isolated from 24 h aged longissimus and iliocostalis muscles required 216 ± 13 kN m -2 and 272 ± 6 kN m -2 , respectively, to fracture. On cooking the muscles for 1 at 80°C the fracture forces increased to 342 ± 19 kN m -2 in fibres isolated from the longissimus and 443 ± 36 kg cm -2 in fibres isolated from the iliocostalis. Ageing the muscles for 72 h halved the forces required to break raw muscle fibres isolated from them. However, further ageing of the muscles had no noticeable effects on the force required to fracture fibres isolated from the longissimus dorsi but caused a further reduction in the stresses needed to break fibres isolated from the iliocostalis muscle. Muscle fibres isolated from the iliocostalis fractured at higher strains than those isolated from longissimus muscle. However, in both muscles the strain at which the fibres fractured increased with cooking temperature and was lowest in fibres isolated from raw muscles and highest in fibres isolated from muscles cooked at 80°C for 1 h. Ageing the muscles led to a marked decline in the strain at which the fibres fractured and these effects were greater in fibres isolated from the longissimus than in fibres isolated from the iliocostalis muscle. In 24 h and 72 h conditioned muscles, fibres having diameters <60 μm required significantly greater forces to fracture than those with larger diameters. However, ageing the muscles for 264 h removed this diameter-dependent difference in fracture force. Fibre diameter had no effect on the strain at which the muscle fibres fractured at all experimental conditions.

LITERATURE ABSTRACTS

GENERAL PRINCIPLES Rheological Behavior and Potential Cross‐Linking of Pacific Whiting Surimi Gel. J.W. Park, J. Yongsawatidgul and T.M. Lin Fracture of Alaska Pollock Gels in Water: Effects of Minced Muscle Processing and Test Temperature. J.R. Howe, D.D. Hamann (corresponding author), T.C. Lanier and J.W. Park Breaking Stress and Syneresis of Rennin Curds from Reconstituted Skim Milk Frozen Concentrate. C‐W. Lin, C‐H., Hsieh and H.‐P. Su Phospholipid Hydrosylate and Antistaling Amylase Effects on Retrogradation of Starch in Bread. M.R. Kweon, C.S. Park, J.H. Auh, B.M. Cho, N.S. Yang and K.H. Park Rheological Studies of Water Soluble (1‐3), (1‐4)‐P‐D‐Glucans from Milling Fractions of Oat. K. Wikstrom, L. Lindahl, R. Andersson and E. Westerlund Shear Induced Starch Conversion During Extrusion. X. Zheng and S. S. Wang Modeling Ice Crystal Coarsening in Concentrated Disperse Food Systems. R.L. Sutton, I.D. Evans and J.F. Crilly A Critique of Some Methods Proposed for Evaluating the Emulsifying Capacity and Emulsion Stabilizing Performance of Vegetable Proteins. P. ShermanMETHODOLOGY &amp; INSTRUMENTATION Arnott Test Correlates with Dynamic Rheological Properties for Determining Cheddar Cheese Meltability. Z. Ustunol, K. Kawachi and H. Steffe Instrumental Probe and Method to Measure Stickiness of Cooked Spaghetti and Noodles. F. Guan and P.A. SeibFACTORS AFFECTING TEXTURE The Influence of Starch on The Rheological Behavior of Micro‐crystalline Cellulose Hydrogels. M. Dolz, F. Gonzalez, M. Herriez and O. Diez‐Sales Textural Properties of Chicken Frankfurters with Added Collagen Fibers. J.‐F. Meullenet, H.C. Chang, J.A. Carpenter and A.V.A. Resurreccion Microstructural and Rheological Properties of Cooked Squid Mantle. M. Kugino and K. Kugino Blanching, Freezing and Frozen Storage Influence Texture of White Asparagus. M.T. Sanchez‐Pineda‐Infantas, G. Cano‐Miinoz and J.R. Hermida‐Bun Texture and Histological Structure of Carrots Frozen at a Programmed Rate and Thawed in an Electrostatic Field. M. Fuchigami, N. Hyakumoto, K. Miyazaki, T. Nomura and J. Sasaki Firmness and Cell Wall Characteristics of Pasteurized Jalapeno Pepper Rings Affected by Calcium Chloride and Acetic Acid. L.R. Howard, P. Burma and A.B. Wagner Draw pH and Storage Affect Rheological Properties of Mozzarella Cheese. J.J. Yun, Y.L. Hsieh, D.N. Barbano Role and Contribution of Starch and Protein Contents and Quality to Texture Profile Analysis of Oriental Noodles. B.X. Baik, Z. Czuchajowska and Y. Pomeranz Effect of Decorticated Sorghum Addition on the Rheological Properties of Wheat Tortilla Dough. P.I. Torres, B. Ramirez‐Wong, S.O. Serna‐Saldivar and L.W. Rooney Influence of 7s and 11s Globulins on the Extrusion Performance of Soy Protein Concentrates. L. Ning and R. Villota Textural Changes in Vegetables During Thermal Processing I. A Descriptive Method to Segregate Effects of Process Treatments. L.A. Moreira, F.A. Rodrigues Oliveira (corresponding author), J.C. Oliveira and R.P. Singh11. Effects of Acidification and Selected Pretreatments on Texture of Turnips. Microbial and Sensory Characteristics of a Fermented Sausage Extended with Carbohydrate Materials. H. Escalona, E.J. Gallardo, I. Guerrero (corresponding author) and E. Ponce Effects of Electrical Stunning Duration on Postmortem Rigor Development and Broiler Breast Meat Tenderness. P.A. Paponaho and D.L. Fletcher Relationships Between Muscle Tissue Characteristics and Sensory Quality of Dry‐Cured Ham. S. Buscailhon, C. Touraille, J.P. Girard and G. Monin Physical and Sensory Properties of Reduced Fat Breakfast Sausage. S. Barbut and G.S. Mittal Tenderness of Prerigor Stretched Porcine Longissimus Muscle. H. Wang, J.R. Claus (corresponding author) and N.G. Marriott Effects of pH and Salts on the Firmness of Canned Ripe Olives. P. Garcia, M. Brenes and A. Garrido Influence of Ageing Time, Storage Temperature and Percentage Lean on the Eating Quality of Pork and Its Relationship to Instrumental and Structural Parameters. E. Tornberg (corresponding author), G. von Seth and A. Goransson Ageing of Beef: Influence of Two Ageing Methods on Sensory Properties and Myofibrillar Proteins. P.H. Heinze and D. Bruggemann Rheological and Textural Behaviour of Double Cream Cheese. Part I: Effect of Curd Homogenization. C. Sanchez (ENSAIA), J.‐L. Beauregard, M.‐H. Chassagne, J.‐J. Bimbenet and J. Hardy Rheological and Textural Behaviour of Double Cream Cheese. Part 11: Effect of Curd Cooling Rate. C. Sanchez (ENSAIA), J.‐L. Beauregard, M.‐H. Chassagne, A. Duquenoy and J. Hardy

Developing a fiber-optic probe to combine subcutaneous fat depth and meat quality measurements

This feasibility study demonstrates that the boundary between porcine subcutaneous fat and longissimus muscle can be detected with a probe using optical fibers to illuminate and detect anatomical boundaries. A relatively large optical window (approximately 3 mm2) seemed to give the best resolution of fat to muscle boundaries, whereas a smaller window gave a better resolution of marbling. Scattered, obliquely sectioned optical fibers gave reflectance spectra of fat and muscle that were relatively flat and parallel (fat > muscle). Thus, white light may be used with optical fibers to detect fat to muscle boundaries, although the greatest monochromatic separation was at 820 nm. In comparing measurements made as the probe penetrated the meat with those made as the probe was withdrawn, structures appeared to be deeper on the way in than on the way out, because of compression of the meat. Multichannel operation allowed tissue transmittance to be measured as well as reflectance and channels to be averaged to improve performance. These observations will be useful in developing new apparatus to measure fat depth and meat quality in one operation using optical fibers.

GLYCOLYTIC POTENTIAL IN PORCINE LONGISSIMUS MUSCLE BEFORE AND AFTER TRANSPORT: AN IN VIVO STUDY

The purpose of this research was to study the effect of transport on the glycolytic potential (GP, very close to glycogen content) measured in vivo of porcine Longissimus muscle. Four groups of 9 (Landrace × Yorkshire) × Hampshire crossbred pigs, corresponding to 4 rearing pens, were transported unmixed for 2 h. Biopsy samplings were performed immediately before and after transport on each pig. GP did not vary significantly when compared before and after transport (–2.2%). As shown by postmortem pH and internal light scattering measurements, no tendency toward the PSE (pale, soft and exudative) or DFD (dark, firm and dry) conditions was observed. It was concluded that a relatively short transport time (2 h) without mixing unfamiliar animals, did not induce high stress, as shown by the stability of muscle glycogen stored in vivo and the lack of deviation in meat quality traits postmortem.

Effect of Heating Temperature and Muscle Type on Porcine Muscle Extracts as Determined by Reverse Phase High Performance Liquid Chromatography

ABSTRACTSamples from porcine longissimus muscles were heated to temperatures ranging from 40–80°C to reach endpoint temperatures (0 min) or held at endpoint temperature for 30 min. Proteins in water‐soluble extracts of these samples were separated and quantified by reverse phase high performance liquid chromatography (RP‐HPLC). After heating to 60°C for 0 min or to 55°C and holding for 30 min, lactate dehydrogenase (LDH), pyruvate kinase (PK) and myoglobin appeared to comprise the bulk of the remaining soluble protein. RP‐HPLC analysis of water soluble extracts from longissimus dorsi, serratus ventralis and psoas major muscles from barrows and sows indicated differences in proportions of LDH and myoglobin.

Post-natal changes in some histochemical and enzymatic characteristics of three pig muscles

Post-natal changes in histoenzymatic and enzymatic characteristics were studied in porcine longissimus, psoas major and tibialis cranialis muscles. The experiment was carried out on thirty-five female large White pigs: fifteen were slaughtered between birth and 120 kg body weight (BW) and twenty at the market liveweight of 100 kg. The relative growth of each of the three muscles in relation to BW appeared to be monophasic, the allometric growth rates differed significantly between muscles: 1·21, 1·08 and 0·97, respectively. Myofibers were classified according to their contractile and metabolic properties as βR, αR and αW fibers. In the three muscles, the percentage of β fibers increased from birth up to 2 months of age and little change occurred thereafter. Glycolytic fibers were detectable only from about one month onwards. Their percentage then increased rapidly up to 30–50 kg BW to reach 60%, 30% and 12% in longissimus, psoas major and tibialis cranialis muscles, respectively. Thereafter, these values only changed slightly. This histoenzymatic differentiation led to the typical type grouping found in pigs. Throughout the period studied, the cross-sectional area of the myofibers increased with some differences according to fiber type and muscle. Lactate dehydrogenase (LDH) specific activity was similar in the three muscles at birth and then increased rapidly up to 4–5kg BW (15–20 days of age), although to a greater extent in the future glycolytic muscle ( longissimus) This increase then abruptly slowed down. The period between 15 and 20 days of age corresponds to a critical stage already known in the rearing of pigs, i.e. growth rate, body composition and food intake. Changes in isocitrate dehydrogenase (ICDH) specific activity were much slighter and differed according to the muscle. There were close correlations between percentages of αW fibers and enzymatic kinetic measurements from one month onwards.

A Technique to Measure Binding Properties of Non‐meat Proteins in Muscle‐Juncture Formation

ABSTRACTJunctures of meat containing five nonmuscle protein products were made by use of a technique in which cubes of porcine longissimus muscle were oriented according to three fiber directions and joined together with certain nonmuscle protein products to form blocks. These blocks were cooked (72°C) and their junctures evaluated for viscoelastic properties. Viscoelastic properties were not different (P &gt; 0.05) among all comparisons of junctures except for those made with sodium caseinate and no protein product (controls) which did not form a juncture. Junctures made with plasma protein (PP) or egg albumin (EA) had higher numerical values for viscoelastic properties than those made with either isolated soy protein (ISP) or vital wheat gluten (VWG). VWG‐junctures had higher numerical values for viscoelastic properties when cooked to 93°C than when cooked to 72°C. The technique of preparing muscle junctures was satisfactory, but techniques for Instron stress‐relaxation measurements of junctures need improvement.

USE OF A RAPID MUSCLE PROTEIN SOLUBILITY TECHNIQUE TO PREDICT BEEF MUSCLE YIELD AS A FUNCTION OF TIME, TEMPERATURE, SALT AND PHOSPHATE

ABSTRACTAn improved muscle protein solubility method has been developed which has two distinct advantages over the traditional method: it requires much less time and may be conducted at room temperature. The pre‐ or post‐rigor sample is homogenized in a Brinkman Polytron in 25 ml buffer and is centrifuged. The supernatant is decanted and soluble protein determined as in the traditional method (biuret). Comparable results were obtained for old vs new method for samples of porcine longissimus muscle which encompassed a wide range of sarcoplasmic and myofibrillar protein solubilities. The new method can also be applied with accuracy equivalent to the traditional method for the determination of solubility in cooked meat samples. A four‐factor response surface experimental design (central composite) was utilized to evaluate the role of process variables and product ingredients on the cooking losses of USDA Utility grade biceps femoris muscle. The factors were cooking time (0.5–12.0 hr), temperature (55–85°C), NaCl (0–4%), and Na tripolyphosphate (0–0.5%): Shrink was determined on ground 25‐g samples by calculating the free moisture lost (as a percentage of total moisture) after centrifugation in Wierbicki tubes. Sarcoplasmic and myofibrillar protein solubility were determined on the same samples by the rapid solubility technique. Stepwise regression was used to tit a multiple polynomial equation to shrink loss and protein solubility (P &lt; 0.001). The results indicated that cooking temperature was decisively the most important factor controlling yield and protein solubility. Shrink and protein solubility were nearly independent of time in the center point regions of the experiment which are, based on the type of design (central composite), the most accurate areas for prediction. Previous studies have demonstrated that the major tenderization reactions in beef are dependent both on time and temperature. Therefore, these findings suggest that improved yield in commercial thermal processes is possible by selecting long‐time, low‐temperature treatments since protein solubility and, therefore, yield are primarily functions of temperature and are relatively independent of time at a given temperature.