Intramuscular Fat

Intramuscular fat (marbling) tends to dilute the connective tissue of elements in muscle in which it is deposited, and this may help explain the greater tenderness reported for beefiness from well-fed proficient-quality animals (Bristles, 1924).

From: Lawrie's Meat Science (Seventh Edition) , 2006

Fatty and fat cells in domestic animals

Steven G. Lonergan , ... Dennis N. Marple , in The Scientific discipline of Animal Growth and Meat Technology (2d Edition), 2019

Intramuscular Fat (or Marbling)

Intramuscular fat ( Fig. 5.14) is located between and within muscle fibers (cells) and its greatest deposition is in the afterwards stages of the growth process. Intramuscular fatty is called marbling in the meat manufacture and marbling has a significant impact on marketing fresh meat, especially beef and pork loin cuts. The higher grades receive higher prices. The degree of marbling is used in the USDA Beef Grading System. The USDA marbling specifications have the highest degree of marbling for the USDA Prime class and lower amounts of marbling for the USDA Pick and Select grades (Fig. 5.15). An illustration of the corporeality of marbling within 6 marbling degrees of the USDA Quality Grades for beef carcasses is shown in Fig. 5.16. The Abundant Marbling and the Moderately Abundant Marbling represents the USDA Prime course; the Moderate, Modest, and Minor degree of marbling represents the USDA Choice form; and the Slight Amount of marbling represents the USDA Select form. The human relationship between the degree of marbling and the per centum of intramuscular fatty is presented in Table 5.6. Marbling is besides important for export standards used for pork sold to Nippon and other Asian nations. Fig. five.17 shows marbling standards used by exporters of quality pork cuts from the United States. Nihon importers of Usa pork will pay a premium for highly marbled cuts. The same marketing concepts for marbling apply to beef exported to Japan.

Fig. 5.14

Fig. 5.14. An example of intramuscular fat in the pork muscle from the loin region of the carcass.

Fig. 5.15

Fig. 5.15. An example of the three levels of intramuscular fatty in beef rib-eye muscle: (12th–13th rib) moderately abundant (Prime), moderate (Choice), slight (Select).

Fig. 5.16

Fig. 5.16. Marbling standards used for the USDA Beef Quality grades. Left column (elevation down): slight, small, modest. Right column (top downward): moderate, slightly abundant, moderately abundant.

 Courtesy of the USDA.

Table 5.half dozen. Relationship betwixt percentage of intramuscular fat, marbling score, and carcass quality grade in beefiness cattle

Class Marbling score Per centum intramuscular fat
Prime + Abundant
Prime ° Moderately abundant 12.three and higher
Prime − Slightly abundant ix.nine–12.ii
Selection + Moderate 7.vii–9.viii
Selection ° Modest five.viii–vii.6
Choice − Small 4.0–five.vii
Select + Slight + 3.1–3.9
Select − Slight − 2.three–3.0
Standard + Traces ii.2 and lower
Standard ° Practically devoid
Standard − Practically devoid −

From Gene Rouse, Courtesy of Animal Scientific discipline Department, Iowa Country Academy.

Fig. 5.17

Fig. 5.17. An example of marbling standards used for the selection of pork for export.

 Courtesy of the National Pork Board, Des Moines, IA.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780128152775000056

Chemical AND PHYSICAL CHARACTERISTICS OF MEAT | Palatability

R.K. Miller , in Encyclopedia of Meat Sciences (Second Edition), 2014

Marbling or Intramuscular Fatty as an Indirect Measure of Meat Tenderness

Intramuscular fat likewise has an indirect relationship to meat tenderness. As animals grow and develop, fat is deposited sequentially into five different fat depots – mesenteric fat; kidney, pelvic, and heart fatty; subcutaneous fat; seam fatty; and marbling or intramuscular fat. Every bit marbing is the last fat depot to be deposited, information technology tin can be used as an indication of growth and nutritional status of animals. If animals are fed loftier free energy-based diets, they grow rapidly or they have loftier rates of protein and lipid accession. Therefore, these animals are heavier with higher levels of subcutaneous, seam, and intramuscular fat and greater muscle mass. These heavier, fatter, and more muscular carcasses arctic slower and are less susceptible to cold-induced toughening. Meat from early postmortem muscle subjected to cold shortening or common cold-induced toughening has shorter muscle contractile state that results in tougher meat. Additionally, animals fed energy-based diets that grow rapidly have higher collagen solubility. Meat that has greater collagen solubility volition be more tender because, during cooking, more than of the collagen matrix (the main component of connective tissue) will melt. Equally more collagen melts, the connective tissue within the muscle will not contribute toward meat toughness or the meat is more tender.

Marbling or intramuscular fat positively affects meat flavor (Tables 1–3). As fat level increases, consumers tend to similar the flavor of beef and pork. Fat has a characteristic flavor and is one of the major components of meat flavor. Many times it is not the predominant flavor in meat, but information technology does provide a residuum with lean meat flavors. When meat contains very depression levels of fat, the predominant flavors are associated with the lean, such as cooked beef lean, serumy, bloody, grainy, metal, livery/organy, and brothy flavor aromatics. As the level of fat or marbling increases, the cooked fat aromatic or flavour increases in meat and this aromatic tin can assistance in decreasing or masking flavor attributes associated with lean, thus providing a rest of meat flavors. The chemical basis of how adipose tissue and lipids contribute toward meat flavor will be discussed in the Department Lipids and Off-Flavor Development.

Read full chapter

URL:

https://world wide web.sciencedirect.com/science/commodity/pii/B9780123847317000854

Factors affecting the quality of raw meat

R.1000. Miller , in Meat Processing, 2002

3.ii.ane Fatty component

Intramuscular fatty content has been shown to affect flavor, juiciness, tenderness and visual characteristics of meat. Savell and Cross (1988) adult the Window of Acceptability to demonstrate the general relationship between the office of increased intramuscular fat on meat pork, lamb and beefiness palatability (Fig. three.1). In full general, as fat content increases, palatability increases; however, improvements in palatability with increasing fat percentage are not equal beyond all fatness levels. If fat content is less than three%, palatability decreases markedly with each decrease in fat percentage. In fact, this is the steepest gradient on the bend. As fat increases from iii% to nigh 6%, meat palatability improves, only not equally dramatically as reported at the lower levels. Every bit fat content exceeds 7.3%, fatty is highly visible and has been identified every bit likewise fatty past health-conscious consumers. Too much visible fatty has raised questions about consumption of fatty in meat products and increased incidence of coronary heart disease, obesity or some forms of cancer in humans; these issues can affect consumers' perception of acceptability. Therefore, meat with fat content between 3 and 7.three% is generally considered acceptable. Diet/health-conscious consumers may be willing to sacrifice palatability for lower fat content.

Fig. 3.one. The Window of acceptability. Adapted with permission from Designing Foods: Animal Product Options in the Marketplace. Copyright 1988 by the National Academy of Sciences.

 Courtesy of the National Academy Press, Washington, DC.

How does intramuscular fat affect palatability? 1 style is through the relationship of intramuscular fat with meat juiciness. As intramuscular fat increases, humans perceive that the meat is juicier. During mastication or during the first bites, if fat is present, some of information technology is released and the salivary glands are stimulated. This results in a perception of juiciness, additionally, meat with a higher fat content may give a longer sustained perception of juiciness. Savell and Cantankerous (1988) stated that 'fatty may affect juiciness by enhancing the waterholding capacity of meat, by lubricating the musculus fibers during cooking, by increasing the tenderness of meat and thus the apparent sensation of juiciness, or by stimulating salivary flow during mastication'.

A second way that intramuscular fat affects palatability is through the relationship between fat content and tenderness. Interestingly, there is conflicting evidence as to the meat tenderness and fat relationship. Savell and Cross (1988) supported the relationship betwixt increased intramuscular fat and meat tenderness past proposing four hypotheses. The first hypothesis, the Majority Density Theory, states that as fatty is lower in density than heat-denatured protein in cooked meat, as the fat percent increases, the overall density of the meat decreases. Equally bulk density decreases within a given bite of meat, the meat is more than tender. The second hypothesis is defined every bit the Lubrication Effect. Intramuscular fat is mainly triglycerides stored in adipose cells embedded in the perimysial connective tissue wall of the musculus. As meat is cooked, triglycerides melt and bathe the muscle fibers. Every bit the meat is chewed, fatty is released, salivation increases and the meat is perceived as juicy. Additionally, the muscle fibers requite or slide more than easily resulting in an increased perception of tenderness. The third hypothesis, the Insurance Theory, states that fat provides protection against the negative effects of over-cooking or loftier estrus on poly peptide denaturation. Meat proteins are involved in binding h2o in the muscle fiber. As meat is cooked, proteins denature and lose some of their power to bind h2o. Fat can act to insulate the transfer of oestrus or slow down the estrus transfer then that protein denaturation is less astringent and less moisture is lost during cooking. The fourth theory or the Strain Theory relates to the weakening of the perimysial connective tissue surrounding muscle bundles. As marbling is deposited as adipose cells dispersed in perimysial connective tissue, development and an increased number of adipose cells weaken the connective tissue structure resulting in more tender meat.

To understand if marbling or intramuscular fat afflicted consumer credence and the subsequent relationship with trained sensory responses, the Beefiness Customer Satisfaction written report was conducted (Lorenzen et al., 1999; Neely et al., 1998; Savell et al., 1999) in the U.s.. Beefiness top loin steaks from four USDA Quality Grade classifications were selected to stand for four Quality Form classifications where Low Select would incorporate beef top loin steaks with Slight00 to Slight50 degrees of marbling that would equate to about 3 to three.5% chemical lipid; Loftier Select steaks had Slight51 to Slight100 degrees of marbling or about 3.5 to 4.0% chemical lipid; Low Selection steaks had a small caste of marbling or about 4 to 5% chemical lipid; and Acme Selection consisted of steaks with small-scale and moderate degrees of marbling or about six to 7% chemic lipid. Chemical lipid approximations were projected from Savell and Cross (1988). Steaks were evaluated by 300 households in four cities where each household contained ii developed consumers who ate beefiness three or more times per calendar week. 4 top loin steaks from each carcass was served to four consumers in each city and i steak was evaluated by a trained meat descriptive attribute panel and Warner-Braztler shear strength was conducted as a mechanical measurement of tenderness every bit described past AMSA (1995). Consumers rated Top Option steaks highest for overall like and juiciness (Table 3.1). They liked the tenderness and flavor of Choice (Top Option and Low Choice) steaks compared to Select steaks and they indicated that the Choice steaks had a higher intensity of flavor than Select steaks. Trained sensory panels likewise indicated that as marbling score increased, cooked beef top loin steaks were juicier, more tender, more intense in flavor and they had college levels of beef flavor and beef fat flavour (Table three.one). Warner-Bratzler shear force values decreased as marbling score increased (Table 3.1). In this same study, superlative sirloin and elevation round steaks besides were evaluated. These steaks had slightly lower fat content than top loin steaks and the marbling to palatability human relationship was non as strong.

Tabular array iii.1. Least squares means of top loin steaks from U.s. Beef Client Satisfaction Study for consumer sensory attributes,a trained meat descriptive sensory attributes and Warner-Bratzler shear forcefulness (kg) as effected by USDA quality form

Quality attribute USDA quality grade Root mean square fault P-value
Top choice Low option High select Low select
Consumer sensory attributes a
Overall like/dislike 19.2 c 19.1 c 18.8 c xviii.7 c 3.06 0.0004
Juiciness eighteen.5 c eighteen.5 c 18.three d 18.0 c three.57 0.0006
Tenderness like/dislike 19.0 cd 19.two d 18.half dozen cd 18.6 c iii.28 0.0001
Season intensity xix.i c 19.2 d xviii.9 cd eighteen.9 c two.87 0.0009
Season like/dislike nineteen.3 cd 19.3 d 19.0 cd eighteen.ix c 2.88 0.0002
Trained meat descriptive sensory attribute b
Juiciness 5.eight d 5.six c 5.5 c 5.4 c 0.58 0.0001
Musculus fiber tenderness 6.seven d 6.6 cd 6.5 c six.5 c 0.58 0.01
Connective tissue amount 6.8 c 6.9 d half dozen.9 c half dozen.ix c 0.45 0.55
Overall tenderness six.6 d 6.6 cd 6.5 c half-dozen.5 c 0.56 0.06
Flavor intensity 5.7 d five.vii d v.6 c five.6 c 0.31 0.002
Beef season intensity 3.5 d three.5 d 3.three c 3.3 c 0.32 0.0001
Beef fat flavor intensity ii.i eastward two.0 d ane.8 c 1.viii c 0.23 0.000a
Mechanical tenderness measurement b
Warner-Bratzler shear force, kg ii.70 d 2.75 d 3.00 c 2.95 c 0.71 0.0002
a
Values from Neely et al. (1998) and Lorenzen et al. (1999). Values differ from those reported as models differed slightly in lodge to generate these least squares ways. Consumers' sensory attributes were rated as 1 = dislike extremely, not at all juicy, not at all tender, dislike extremely, and no season at all, respectively and 23 = like extremely, extremely tender, extremely juicy, like extremely, and an extreme corporeality of flavor, respectively.
b
Values are unpublished data, just they were derived from the same data set equally published by Neely et al. (1998) and Lorenzen et al. (1999).
cde
Least squares means inside a row and a cut lacking a common superscript differ (P < 0.05).

In pork, a like written report was conducted in three cities with pork consumers in the U.s.. Pork loin chops were selected to vary in pH, lipid content and tenderness as adamant by Warner-Bratzler shear force value (Table 3.two). Pork consumers in the Usa did not rate pork loin chops differently based on lipid content. However, when a similar study was conducted with Japanese consumers (Table three.3), Japanese consumers rated pork loin chops with college National Pork Producer Council (NPPC) marbling score (NPPC marbling scores are a visual assessment of intramuscular fat and they are related to a chemical lipid value) as juicier, they liked the flavor and taste, they liked the color and they tended to like the corporeality of fatty and visual appearance. Pork loin chops with the highest level of lipid tended non to be preferred by Japanese consumers most likely due to likewise much visible fat. In summary, there is a marbling to meat palatability relationship, but this relationship may vary across meat species and across consumer populations. While this relationship is non stiff across all meat species, increased marbling or intramuscular fat assists in improving the eating quality of meat.

Table three.ii. To the lowest degree squares ways for pork consumer sensory traits a as afflicted by predetermined categories of lipid, Warner-Bratzler shear force, and pH from loin chops from the US Pork Consumer Sensory Study.

Trait n Juiciness Tenderness Flavor Overall similar
pH category 0.04 0.0165 0.06 0.03
  Low 648 iii.3 d 3.three d 3.ii 3.2 d
  Medium 620 3.3 d three.3 d 3.2 three.2 d
  High 498 3.five e 3.4 east iii.4 3.4 due east
RSD c 1.13 1.08 1.10 i.03
Lipid category 0.20 0.19 0.09 0.18
  Low 427 3.4 3.3 three.3 3.2
  Medium 857 3.3 3.3 3.2 iii.2
  High 482 3.iv 3.4 3.4 3.3
RSD c ane.three 1.08 1.05 1.03
Shear category 0.0004 0.0001 0.0004 0.0001
  High 379 3.2 d 3.1 d 3.1 d iii.0 d
  Medium 844 3.4 d 3.iii east 3.3 e three.3 e
  Low 520 3.5 e iii.5 f 3.4 eastward 3.4 e
RSD c 1.12 1.07 one.05 ane.03

b P-value from the Analysis of Variance table.

a
Consumer attributes were evaluated using a 5-betoken hedonic, end-anchored sensory scale where 1 = dislike extremely and five = like extremely.
c
RSD = Residuum Standard Deviation from the Analysis of Variance tabular array.
def
Least squares ways inside a column and a trait defective a common superscript differ (P < 0.05).

Adapted from Miller et al. (2000).

Table iii.three. Least squares ways for consumer sensory scores of pork loin chops from the Japanese Pork Consumer Study that vary past NPPC marbling scores determined at the 10th rib in the Longissimus musculus.

Consumer aspect Marbling score c
one 2 3 four 5 6 P Value
Aroma like/dislike a 3.20 3.11 3.16 iii.27 3.87 3.00 0.13
Juiciness similar/dislike a 3.09 de 3.00 d 3.01 de 3.13 de 4.12 eastward 3.36 de 0.048
Tenderness like/dislike a 3.34 iii.29 3.25 iii.39 4.25 three.82 0.07
Flavor like/dislike a 3.fifteen d 3.19 d 3.14 d 3.29 d four.12 eastward 3.64 de 0.04
Overall taste like/dislike a 3.15 d three.16 d 3.12 d 3.34 de 4.25 f 3.82 ef 0.006
Appearance like/dislike a 3.01 d 3.xi de 3.19 de 3.32 de 3.75 e 2.82 d 0.02
Color like/dislike a 3.07 d 3.17 d 3.23 de 3.28 de 3.87 east 2.82 d 0.04
Colour intensity b iii.16 d three.36 de iii.15 d 3.25 a 3.87 e two.91 d 0.02
Corporeality of fat similar/dislike a 3.06 d 3.19 de three.26 e 3.36 e iii.75 eastward three.09 de 0.02
Overall visual like/dislike a 3.00 d 3.13 d iii.23 d iii.34 d 3.50 d ii.82 d 0.009
a
Consumer attributes were evaluated using a five-point scale where 1 = dislike extremely and v = similar extremely.
b
Consumer attributes were evaluated using a 5-point scale where 1   = calorie-free and 5 = nighttime.
c
National Pork Producers Council new fresh meat marbling scores where one<1% lipid, two = 2% lipid; iii = three% lipid, iv = 4% lipid, v = 5% lipid and 6 >   half-dozen% lipid.
def
Least squares ways within a row lacking a mutual superscript differ (P < 0.05).

Adapted from Miller et al. (2000)

Intramuscular fatty also has an indirect relationship to meat tenderness. As animals grow and develop, fat is deposited sequentially and marbling is the concluding fat depot to fill. Marbling therefore is an indication of growth and nutritional status of animals. If animals are fed high-free energy-based diets they abound rapidly or they take high rates of protein and lipid accession. The end event is heavier animals with higher levels of subcutaneous, seam and intramuscular fat and greater muscle mass. These heavier, fatter and more muscular carcasses chill slower and are less susceptible to common cold-induced toughening (see word in iii.2.two). Additionally, animals fed energy-based diets, that grow rapidly have higher collagen solubility (run into give-and-take in 3.2.3) that improves meat tenderness. It becomes apparent that interrelationships betwixt the connective tissue, muscle fiber and fat component are involved in understanding meat palatability.

Marbling has been shown to affect consumer and trained sensory panel meat flavor attributes (Tables three.1, 3.2, 3.3). As fat level increases, consumers tend to like the flavor of beef and pork. Fat has a feature season and has been identified as one of the major components of the meat flavor dictionary (Johnsen and Civille, 1986). Whereas fat is not the predominant flavor in meat, information technology provides a remainder between lean and fat flavors. When meat contains very low levels of fatty, the predominant flavors are those associated with the lean such equally cooked beef lean, serumy, encarmine, grainy, metallic, livery/organy, and brothy (Johnsen and Civille, 1986; Lyon, 1987). As the level of fatty or marbling increases, the cooked fat effluvious or flavour increases in meat and this aromatic tin assist in decreasing or masking flavor attributes associated with lean, providing a balance of flavors.

Read full chapter

URL:

https://www.sciencedirect.com/science/commodity/pii/B9781855735835500078

Real-time ultrasound (RTU) imaging methods for quality command of meats

S.R. Silva , 5.P. Cadavez , in Calculator Vision Technology in the Food and Drinkable Industries, 2012

11.half dozen.1 Using RTU image analysis for International monetary fund prediction

The IMF is primarily adamant by the distribution blueprint of fat flecks in a cross-section of the LTL muscle, usually betwixt the 12th and the 13th thoracic vertebrae (Fig. 11.5a). Although IMF is present in other muscles, the assessment generally is performed on a LTL muscle department. The IMF consists of deposits that occur within the musculus, which are irregular either in form or in their dispersal. These deposits represent a cluster of Imf cells. Individual cells can be very small (40–lx   μm) and are not visible to the homo eye (Betimes., 2004). The crude surface and modest size of IMF deposits cause audio waves to besprinkle (Brethour, 1990; Whittaker et al., 1992), producing spots on RTU images that are referred to equally speckles (Fig. 11.5b). This is why ultrasound techniques have the potential to predict IMF in vivo after RTU prototype assay (Brethour, 1990; Whittaker et al., 1992).

Fig. 11.5. (a) Image from a cattle lumbar cut section showing LTL musculus and intramuscular fat flecks and (b) RTU image of the LTL muscle showing speckle originated from International monetary fund.

The RTU epitome assay for predicting IMF or marbling has been carried out in a number of ways over the years. Early studies were conducted to predict marbling scores from a subjective analysis of the RTU epitome features (coherent speckle, attenuating and reverberation) from which a speckle score was obtained (Harada and Kumazaki, 1979; Brethour, 1990). Speckle scores were estimated visually and corresponded subjectively to a point classification scheme. This process had the benefit of allowing an immediate estimation of the marbling score and, thanks to the portability of the ultrasound equipment portability, could be used for farm animals (Brethour, 1990). All the same, it is subjective, and dependent on axle geometry and auto calibration. Furthermore, an agreement of the nomenclature scheme and calculation of the score can exist difficult for a technician to acquire (Brethour, 1990). These negative aspects led Brethour (1990) to observe that ultrasound speckle was a 'quick and muddied' manner to estimate the marbling score of a carcass and that, consequently, farther improvements were necessary to reduce the subjectivity of RTU images. Although a skilled ultrasound technician can visually interpret an RTU epitome and estimate marbling in a live creature with fair accuracy (Brethour, 1990, 1994), it was recognized that enquiry using mathematical models for RTU epitome assay was imperative (Amin et al., 1993; Kim et al., 1998).

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780857090362500119

Supplementing selenium and zinc nanoparticles in ruminants for improving their bioavailability meat

J. Efrén Ramírez Bribiesca , ... Atmir Romero Pérez , in Nutrient Delivery, 2017

v Selenium and Zinc in Muscle

Intramuscular fat content and composition of fatty acids are important in meat quality. Fatty is susceptible to oxidative degradation due to the natural turnover, oxidation of lipids and membrane phospholipids ( Combs and Regenstein, 1980). Selenium acts on selenoenzyme (Papp et al., 2007), prevents or delays the oxidative reactions. Little research has been done showing a relationship between Se and meat quality. Furthermore, the shelf life of packaged meat is a major marketing trouble due to deterioration in color and microbiological growth. Selenium and vitamin E are the main compounds used to meliorate the color stability and lipid muscle. It has been shown that the addition of Se and vitamin Due east reduces lipid oxidation (Combs and Regenstein, 1980). In reference to Zn, the ideal is to use sources of Zn or vehicles that tin can improve assimilation and reduce fecal excretion and Zn deficient consumption, causes absorption coefficients in the small intestine of between 3% and 38%. Zinc absorption, as mentioned, appears to be regulated by the synthesis of a protein termed abdominal metallothionein (Liuzzi and Cousins, 2004). Zn so passes to portal circulation through the Zn transport poly peptide-one (ZnTP-1), reaching the liver and other tissues, such equally muscle. Approximately seventy% of the Zn is bound to circulating albumin. No specific anatomical site office every bit reserve Zn and consequently, no conventional reserves in tissues that can exist released or stored; however, products of beast origin take a high Zn content, while legumes incorporate very low levels of Zn. The Zn replacement in the torso is slow, with a maximum biological life of 250 days. Zinc body reserves are small and have a rapid turnover rate. Therefore, the continuous supply of Zn in ruminants necessary, this can be achieved with intraruminal bolus ho-hum release or administration of nanoparticles, so that information technology can maintain suitable or high amounts in muscle tissue (Munday et al., 2001).

Read full affiliate

URL:

https://www.sciencedirect.com/science/article/pii/B9780128043042000196

Quality indicators for raw meat

M.D. Aaslyng , in Meat Processing, 2002

8.3.i Intramuscular fatty and fatty acid composition

The content of intramuscular fat or the degree of fat marbling has a great influence on the eating quality beginning when the consumers choose the meat in the supermarket. Many consumers will reject buying meat with a medium or high amount of visual fat marbling both in beef and pork even though they find it more palatable when eaten without knowing the amount of fatty ( Grunert, 1997; Bredahl et al, 1998; Brewer et al., 2001a), Bligaard, 2002, Pers. comm.).

At that place are conflicting results on the influence of International monetary fund on tenderness. It is said to increase both the tenderness of the meat (DeVol et al., 1988; Cameron and Enser, 1991; Gwartney et al., 1996; Fernandez et al., 1999; Candek-Potokar et al., 1999; Laack et al, 2001; Brewer et al, 2001a; D'Souza and Mullan, 2002) and to have no effect or even a negative effect (Göransson et al., 1992; Kipfmuller et al., 2000). The reason for these results could be, that variations in IMF are always confounded with other variations, which also have significance for tenderness. The age of slaughter and the slaughter weight influence the content of International monetary fund (Johnson et al., 1969; Candek-Potokar et al., 1999) but can besides influence factors like the content and force of connective tissue and in this way influence the tenderness. Feeding strategy not merely influences the IMF content (Blanchard et al., 1999) but also the growth rate and thereby the proteolytic activity that is of significance for the tenderisation of the meat during ageing (Therkildsen et al., 2002). The genetic background also contributes to variations in IMF. In pork some breeds like the Chinese breeds and Berkshire have an extremely high fat content. In the more commercial breeds Duroc especially is known to take a higher content of IMF compared to the white breeds like Landrace and Large White. It has been shown yet, that the correlation between IMF and sensory quality depends on brood (Fjelkner-Modig and Persson, 1986). The fat acid limerick can besides influence the upshot of International monetary fund on tenderness. In pork the saturated and monounsaturated fat acids are positively correlated to tenderness where polyunsaturated fatty acids are negatively correlated to tenderness (Cameron and Enser, 1991; Eikelenboom et al., 1996). The fatty acid composition is dependent on both breed (Garcia et al., 1986; Tejeda et al., 2001) and feed (Engel et al, 2001).

It has as well been said that a high content of International monetary fund would improve the robustness of the meat against a non-optimal cooking. This was shown in beef past Cummings et al., (1999) who plant a decline in tenderness in meat with a low International monetary fund content when cooked to 80   °C while meat with a high International monetary fund content was however tender at this finish-betoken temperature. The difference between the two groups at 70   °C finish-point temperature was only pocket-sized. It was not possible to notice a similar effect in some other study (Rymill et al., 1997) and the effect of IMF on the robustness of the meat might therefore interact with other matters, every bit the direct upshot of IMF on tenderness is said to practice.

Juiciness is the feeling of moisture in the mouth during chewing. Information technology is a dynamic attribute changing during the chewing process. The content of Imf is positively correlated to juiciness (Savell and Cross, 1988; Gwartney et al. 1996; Flores et al., 1999; Cummings et al., 1999; Brewer et al. 2001a). Some investigations indicate peculiarly that the sustained juiciness experienced during the last part of the chewing procedure, is increased by increasing corporeality of IMF (Savell and Cross, 1988; Aaslyng et al., 2002). An increasing amount of Imf also implies a decrease in cooking loss (Aaslyng et al., 2002). Juiciness is to some extent negatively correlated to cooking loss (Tornberg and Goransson, 1994; Toscas et al., 1999; Aaslyng et al., 2002) and the decreased cooking loss could explain role of the result of IMF on juiciness.

The content of Imf also influences the flavour of meat (Candek-Potokar et al., 1998; Fernandez et al. 1999). This might be due to production of a volatile component as the fat acid composition is important to the flavour. In pork the content of polyunsaturated fatty acids is correlated with abnormal flavour while monounsatuated and saturated fatty acids are correlated with pork season and overall liking (Cameron and Enser, 1991; Cameron et al., 2000). In beef information technology has been found that the meaty aroma was due to phospholipids and non to such a great extent to triglycerides (Mottram and Edwards, 1983). Flavor is a limerick of volatile and nonvolatile components. It is not investigated how IMF influences the nonvolatile flavour components simply part of the unspecified effect on flavour could be due to facilitating the contact between the flavour components and the taste buds.

Read total chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9781855735835500121

Saturated fatty reduction in butchered meat

M.R. Matthews , in Reducing Saturated Fats in Foods, 2011

ten.v.1 Role of fat in the tenderness of meat

It is mainly the intramuscular fat that is considered important for the tenderness of meat. This is the fat within the muscle itself, which at low levels is invisible and at higher levels becomes visible as 'marbling'. This might be thought to have an effect on tenderness in a number of means. Fat tissue within the muscle might substitute for muscle that, within a given piece, is diluted with softer tissue, thus reducing the overall strength required to bite through the meat. This might be considered to be a likely result at college levels of intramuscular fat. Alternatively, or in combination, the fatty might weaken the structural integrity of muscle, perchance preventing cross links forming between connective tissue of musculus fibre proteins, thus enabling the muscle to exist cleaved up more readily in the oral cavity. A further possible effect in the mouth is the potential for fatty to lubricate during chewing, reducing resistance to the teeth through reduced friction. Studies to evaluate these effects in the oral cavity are very difficult to acquit and generally sufficient useful information is obtained by the use of trained sensory panels assessing the overall tenderness (or toughness) of the meat. The complex nature of chewing, however, means that care should exist taken in the interpretation of results from instrumental measures of toughness. These should just be relied upon as a guide to the sensory perception of quality.

Where an issue of fatness on the tenderness of meat has been observed it is usually positive. Across the range of fat contents seen normally in British blood-red meat, notwithstanding, the effect is by and large small, such that fifty-fifty a doubling of the fat content would have merely a very small bear on on the sensory perception of tenderness. Having said that, the literature is consistent, with a decline in tenderness for meat from those animals at the very leanest cease of the scale, suggesting that a minimum level of intramuscular fat is required to forbid damaging tenderness. Below about 2.five% intramuscular fat beef tenderness has been seen to pass up sharply, but above that there is very little issue of intramuscular fat (Buchter, 1986). Similarly, research at the Meat and Livestock Commission'southward Stotfold Hog Evolution Unit found that Ptwo fatty depths below 8   mm were associated with tougher meat (MLC, unpublished information).

A further benefit of fat in meat tenderness is the insulating effect information technology has on the carcase immediately post slaughter. The muscle in fatter carcases cools more slowly mail service slaughter. When muscle chilling is also rapid a toughening effect, called cold shortening, can occur. The slower cooling of fatter carcases can reduce this effect, resulting in manifestly more tender meat. If chilling is considerate, however, this advantage to fatter carcases disappears. This outcome is peculiarly credible in smaller lamb carcases, which cool more rapidly.

Read full affiliate

URL:

https://world wide web.sciencedirect.com/science/article/pii/B9781845697402500105

The function of lipids in food quality

Z.E. Sikorski , Thousand. Sikorska-Wiśniewska , in Improving the Fat Content of Foods, 2006

nine.4.1 The role of lipids in the texture of meat and meat products

The amount and distribution of intramuscular fatty take been regarded as important characteristics of meat quality and are recognized as ane of several criteria in establishing beef carcass quality grades. The degree of marbling is adamant visually in cantankerous-sections of the longissimus dorsi muscle. Amongst some professionals there is a belief that marbling contributes to meat tenderness. However, no unequivocal published bear witness has been found showing high positive correlation betwixt the contents of intramuscular fat and meat tenderness. The benign effect of marbling on meat quality may be due to the lubricating activeness of the fat layers during chewing and swallowing, which may be perceived as increased tenderness of tough meat samples. Intramuscular fat uniformly distributed on the cross-section of the meat cut, in express corporeality, improves the flavour and juiciness, while meat with almost no marbling may exist dry and scarce in flavour. The consequence of fat on the tenderness of meat is also treated by Moloney in Chapter xiii.

The consistency of the fatty tissues in meats depends on the FA limerick of the fat, which in turn is affected past the characteristics of the fats independent in the feed given to the slaughter animals. This is especially pronounced in pork. Owing to solidification acquired by chilling, the subcutaneous fat and marbling increase the firmness of the carcass and retail cuts and contribute to retaining the characteristic shape during treatment and processing of meat.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9781855739659500091

Transcriptomics of Meat Quality

B. Guo , B.P. Dalrymple , in New Aspects of Meat Quality, 2017

2.two.6 Why the Wide Range of Unlike Genes Implicated?

The relationship between gene expression and Imf% is confusing, with express overlap of gene lists between many of the publications on the subject even inside a single species (Table 11.two). Simply despite the variation in results from the broad range of investigations, the expression of genes involved in the synthesis and storage of LCFAs and TAG, which is biologically sensible, appears to be the most consistently related to Imf% in ruminants. There are a number of explanations for the broad variation in genes identified and the credible lack of congruence betwixt many of the results:

•

There are fundamental differences in the mechanism of LCFA and TAG synthesis under different conditions, or in different muscles, or at different ages.

•

Given the conserved nature of the pathways for LCFA and TAG synthesis in adipose tissues in mammals, this appears quite unlikely.

•

The transcriptomic information are unreliable and inherently noisy.

•

Early microarray platforms and qPCR-based approaches are not sufficiently comprehensive.

•

Biological, and probably to a lesser extent technical, dissonance will be a significant contributor to variation betwixt experiments, particularly with small numbers of samples and where the differences in expression of the responsible genes between the groups are pocket-sized.

•

It is likely to lead to partial identification of sets of important genes equally individual genes miss the cutoffs.

•

GAPDH, a widely used reference gene for qPCR, has been shown to be unsuitable for studies on International monetary fund (Zhu et al., 2015).

•

Differences in the rate of utilization of stored lipids accept as well been proposed to touch on IMF% and could be a confounding factor in the relationship between cistron expression and IMF%.

•

The expression of genes encoding lipolytic enzymes has been reported to exist both lower (Hamill et al., 2012; Zhao et al., 2009) and higher (Jeong et al., 2013; Lim et al., 2015) in high-IMF% animals than in depression-IMF% animals. In one written report Jeong et al. (2012) demonstrated that the expression level of the TAG synthesis gene glycerol-three-phosphate acyltransferase, mitochondrial (GPAM, aka GPAT1) explained more than half the variation in Imf, with the next largest effect factor being the TAG degradation gene patatin-similar phospholipase domain containing 2 (PNPLA2, aka ATGL). While expression of GPAM was correlated with International monetary fund% in our analysis, its expression was not highly correlated with the expression of the other genes in TAG synthesis and storage gene set across development (De Jager et al., 2013). In our analysis the expression of genes encoding lipolytic enzymes was not positively or negatively correlated with Imf% (De Jager et al., 2013; Guo et al., 2014).

•

Some of the experiments with immature animals take been undertaken when Imf% is decreasing; run across, for instance, in goats (Wang et al., 2015a). Under these conditions the signals from IMF deposition (if this is occurring at this fourth dimension) and utilization are likely to be mixed and to represent different processes.

•

The expression of the LCFA and TAG genes reflects current Imf% deposition rate, while the measurement of Imf% itself reflects the entire history of the individual.

•

The electric current rate and the history are non always coinciding, peculiarly in sick, young, and old animals. Thus animals on unlike growth trajectories and at different stages of their growth are difficult to compare.

Since many of the analyses were conducted on animals in which the deposition of International monetary fund was likely to be reaching maturity (Fig. 11.2), the concluding 2 explanations, and the partial representation of pathways, appear to be the virtually likely explanations for the lack of meaning overlaps in many cases. The conflicting results in genes identified in very young animals are likely to reflect the remainder of IMF synthesis and utilization under the particular conditions of the experiment. It appears likely that expression of FABP3 may be associated with the use of LCFAs (including International monetary fund) as an free energy source in very young animals, explaining the correlation of the expression of FABP3 with International monetary fund% in these animals, simply also the inconsistent results depending on the historic period and metabolic status of the animals. The expression of FABP3 may be a useful marker for the utilization of IMF and the ratio of expression of deposition genes to FABP3 may have more than utility for estimating net degradation of IMF than the deposition genes alone.

The reason for the absence of a stiff clan between LCFA and TAG synthesis and storage genes and IMF% in the majority of investigations is not so clear for pigs and chickens, just, in addition to the factors mentioned previously, may also reflect the low IMF% (in pigs) and the relative roles of circulating and de novo synthesized LCFAs in deposited TAG.

With the exception of PPARG and CEBPA, there is fifty-fifty less consistency in the genes identified every bit potential regulators of lipogenesis. It appears unlikely that investigating animals reaching maturity in Imf deposition will readily identify regulators of Imf degradation. Such experiments should be undertaken during the earlier stages of Imf deposition when the genes encoding proteins involved in the synthesis and storage of LCFAs and TAG are correlated with IMF% (and virtually likely too IMF deposition rate).

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9780081005934000126

Chemical and Biochemical Constitution of Muscle

Clemente López-Bote , in Lawrie´s Meat Scientific discipline (8th Edition), 2017

4.3.three Sex

In general, males have less International monetary fund than females, whereas the castrated members of each sexual activity have more IMF than the respective sexually entire animals and college concentration of saturated fat (Wood et al., 2008).

As assessed from a representative sample of UK animals, entire pigs were plant to have a greater concentration of heme paint (myoglobin plus hemoglobin) in their Longissimus dorsi muscles than castrates (Warriss, 1990). Because the meat of mature boars can be associated with an unpleasant aroma, it is important to be able to find the presence of meat from male pigs in various products.

Read full affiliate

URL:

https://world wide web.sciencedirect.com/scientific discipline/commodity/pii/B9780081006948000042