Composition, Functionality and Utilization of Pork Variety Meats Rodrigo Tarté, Ph.D. Assistant Professor Meat Science and Technology Iowa State University 215D Meats Laboratory 914 Stange Road Ames, IA 50011-1001 rtarte@iastate.edu Novel Processing Pork Variety Meat Workshop Ames, IA 17 August 2016
Outline Definitions Meat By-Products Variety Meats Composition and Nutritional Value of Edible Pork By- Products Functionality of Edible Pork By-Products Utilization of Edible Pork By-Products References R. Tarté 17 Aug 2016 2
I. Definitions R. Tarté 17 Aug 2016 3
Meat Practical definition: the edible postmortem component originating from live animals, particularly domesticated cattle, hogs, sheep, goats and poultry, as well as wildlife such as deer, rabbit and fish. USDA definition: The part of the muscle of any cattle, sheep, swine, or goats which is skeletal or which is found in the tongue, diaphragm, heart, or esophagus, with or without the accompanying and overlying fat, and the portions of bone, skin, sinew, nerve, and blood vessels which normally accompany the muscle tissue... R. Tarté 17 Aug 2016 4
By-Products All parts of live animal that are not part of dressed carcass 25 30% of hog live weight >6% of hog value Also referred to as offal Not of skeletal origin, therefore most do not meet the definition of meat R. Tarté 17 Aug 2016 5
By-Products Categories Edible (variety meats) Organs: Hearts, livers, brains, kidneys, sweetbreads (pancreas), chitterlings (cleaned large intestines) Other tissues: Tongues, head/cheek meat and trimmings, snouts, lips, skins, rinds, fat, blood, certain bones 35% of pork export volume Inedible Skin, teeth, bones, fat (grease), feet, cartilage/ligaments, glands, lungs, blood R. Tarté 17 Aug 2016 6
Variety Meats Edible by-products that are segregated, chilled and processed under USDA inspection Tend to be more perishable than carcass meats, therefore must be chilled/frozen quickly R. Tarté 17 Aug 2016 7
Approximate Yield of Pork By-Products Item kg Live weight, kg 100 Dressed carcass 77.5 Bone 17.0 Blood 3.0 Fatty tissue 3.0 Skin 6.0 Organs 7.0 Head 5.9 Viscera (chest and abdomen) 10.0 Feet 2.0 Tail 0.1 Brain 0.1 Source: Liu D-C, Ockerman HW. 2001. Meat co-products. In: Hui YH, Nip W-K, Rogers RW, Young OA, editors. Meat science and applications. New York: Marcel Dekker. p. 583 R. Tarté 17 Aug 2016 8
Approximate Yield of Various Items Obtained from US No. 1 Pigs Item kg % of LW Live weight, kg 115 Dressed carcass 85 73.9 Retail cuts 67 58.3 By-products 26 22.6 Edible fats 17 14.8 Variety meats 4 3.5 Blood 5 4.3 Inedible fats, bone, meat scrap 9 7.8 Unaccounted items (stomach contents, shrink, etc.) 13 11.3 Source: Aberle ED, et al. 2012. Principles of meat science. 5th ed. Dubuque (IA): Kendall Hunt. p. 354. R. Tarté 17 Aug 2016 9
II. Composition and Nutritional Value of Edible Pork by-products R. Tarté 17 Aug 2016 10
Nutritional Value of Variety Meats Good to excellent sources of many essential nutrients Some contain large amounts of connective tissue, which contains lower quality protein (nutritionally and functionally) R. Tarté 17 Aug 2016 11
Composition and Nutritional Value of Raw Pork Variety Meats Item Moisture (%) Protein (%) R. Tarté 17 Aug 2016 12 Fat (%) Carbohydrate (%) Blood 79.2 18.5 0.1 0.1 Brain 78.4 10.3 9.2 0.0 Chitterlings 66.3 10.1 23.1 0.0 Ears * 61.3 22.5 15.1 0.0 Feet * 58.3 22.1 18.8 0.0 Heart 76.2 17.3 4.4 1.3 Jowl 22.2 6.4 69.6 0.0 Kidney 80.1 16.5 3.3 0.0 Lard 0.0 0.0 100.0 0.0 Leaf fat 4.09 1.8 94.2 0.0 Liver 71.1 21.4 3.7 2.5 Lungs * 79.5 14.1 2.7 0.0 Pancreas 67.2 18.6 13.2 0.0 Spleen 78.4 17.9 2.6 0.0 Stomach * 73.6 16.5 9.6 0.0 Tail 46.1 17.8 33.5 0.0 Tongue 65.9 16.3 17.2 0.0 * High content of connective tissue Source: Anderson BA. 1988. Composition and nutritional value of edible meat by-products. In: Pearson AM, Dutson TR, editors. Edible meat by-products. London (UK): Elsevier Applied Science.
Composition and Nutritional Value of Raw Pork Variety Meats : content at least equivalent to lean pork tissue : content 3X lean pork tissue Adapted from: Anderson BA. 1988. Composition and nutritional value of edible meat by-products. In: Pearson AM, Dutson TR, editors. Edible meat by-products. London (UK): Elsevier Applied Science. R. Tarté 17 Aug 2016 13
Market Value of Pork By-Products Source: https://www.ams.usda.gov/mnreports/nw_ls446.txt. Accessed Aug 12, 2016 R. Tarté 17 Aug 2016 14
III. Functionality of Edible Pork By-Products R. Tarté 17 Aug 2016 15
Functionality Functionality in food Definition: Any physicochemical behavior of a food material (protein, ingredient, etc.) during processing which affects final product quality and stability Often termed technological quality or technological functionality May vary by product suitability Functional properties often determined by interactions between food components (proteins, lipids, water, etc.) and/or environmental factors. Not the same property as that of so-called functional foods R. Tarté 17 Aug 2016 16
Functionality, cont. Meat functionality typically a function of protein quantity and quality, which are, in turn, characteristic of specific muscle types Muscle types: 1. Skeletal 2. Cardiac 3. Smooth R. Tarté 17 Aug 2016 17
Types of Muscle 1. Skeletal Muscles attached to the skeleton Responsible for movement Multinucleated cells (100 200 nuclei per cell) Under voluntary nervous control Processing functionality dependent on relative proportions of predominant proteins Myofibrillar proteins Myosin, actin Most functional Connective tissue proteins Collagen, elastin Low functionality; generally detrimental to product quality R. Tarté 17 Aug 2016 18
Organization of Skeletal Muscle and Location of Key Proteins R. Tarté 17 Aug 2016 19
Types of Muscle 1. Skeletal, cont. Most edible meat by-products of skeletal origin are of low to intermediate functionality, primarily due to high collagen content E.g., skirts (diaphragm muscle), weasand meat (lining that surrounds esophagus), tongue, head/cheek meat R. Tarté 17 Aug 2016 20
Types of Muscle 2. Cardiac Found only in heart Mononucleated cells Under involuntary nervous control Low processing functionality R. Tarté 17 Aug 2016 21
Types of Muscle, cont. 3. Smooth Walls of digestive tract, blood vessels, reproductive tract, viscera Mononucleated cells Under involuntary nervous control Most predominant muscle type in some variety meats Minimal to no processing functionality E.g., stomachs Organ meats typically do not contain muscle cells at all and are, therefore, not technologically functional Must also consider content of pigment protein myoglobin R. Tarté 17 Aug 2016 22
Functionality, cont. Functionality generally thought of in terms of: Bind: ability of meat raw material to hold meat system together by binding water and fat Bind Index: g of oil emulsified by one g of meat (Labudde & Lanier, 1995) Color: concentration of red meat pigment myoglobin Color Index: expression of mg of pigment per 100 g of protein (Saffle, 1966) R. Tarté 17 Aug 2016 23
Functionality, cont. Material Functional indices of various pork raw materials Bind Index Color index Material Bind Index Color index Beef Bull Meat * 30.01 46.53 Head Meat 7.49 15.62 Beef 85% Trim * 24.43 38.56 Hearts 6.12 32.28 15% Trim 3.16 1.20 Skinned Jowls 4.53 1.76 50% Trim 11.73 9.02 Livers 2.11 49.44 80% Trim 19.25 16.59 Neckbone Trim 18.78 15.74 Bacon Ends 0.08 2.55 Bnls Picnics 20.10 15.90 Backfat/Belly Trimmed 7.70 5.91 Picnic Trim 18.19 15.62 Backfat, Untrimmed 1.13 0.90 Picnic Hearts 23.01 19.34 Belly Strips 6.14 4.73 Regular Trim 9.60 83.56 Blade Meat 23.75 19.97 Skins 0.00 0.00 Cheek Meat, Trimmed 8.61 28.66 Snouts 2.50 0.50 Cheek Trim 3.64 21.09 Spleens 0.74 55.65 Diaphragms 15.95 18.11 Stomachs, Scalded 0.01 0.01 Backfat 0.01 0.01 Tongue Trim 7.11 29.64 * Beef materials shown for reference Source: Labudde RA, Lanier TC. 1995. Protein functionality and development of bind values. Proceedings of the 48th Annual Reciprocal Meat Conference; 1995 Aug 20 25; San Antonio, TX. Chicago (IL): American Meat Science Association. p. 59 68. R. Tarté 17 Aug 2016 24
IV. Utilization of Edible Pork By-Products R. Tarté 17 Aug 2016 25
Main Uses of Edible Pork By-Products R. Tarté 17 Aug 2016 26
Major Uses of Edible Pork By-Products Direct consumption Sausage component Food ingredient Food ingredient source Sausage container Pet food R. Tarté 17 Aug 2016 27
Major Uses of Edible Pork By-Products Direct consumption Sausage component Food ingredient Food ingredient source Sausage container Pet food R. Tarté 17 Aug 2016 28
Edible Pork By-Products as Sausage Components Use is primarily dependent on bind and color Functional meats Mainly those of skeletal origin Low functionality limits their use High connective tissue meats typically limited to 20% of meat block (test to be sure!) Used mainly to control or reduce product cost Non-functional sausage components E.g., livers in liver sausage or braunschweiger Show meats Meats that provide color/contrast/visual appeal but no functionality E.g., hearts in cotto salami R. Tarté 17 Aug 2016 29
Edible Pork By-Products as Ingredient Sources Main types of non-meat ingredients derived from edible pork by-products Source Ingredients Blood Blood plasma (liquid, frozen, dried) Whole blood (liquid and dried) Red cell protein (decolorized) Plasma transglutaminase Bone Gelatin (type B) Edible bone collagen (ossein) Bone collagen hydrolysates (stocks and broths) Edible bone phosphate Edible fat Pig skin Gelatin (type A) Stocks and broths Collagen-rich tissues Concentrated collagen Collagen hydrolysates Source: Tarté R. 2009. Meat-derived protein ingredients. In: Tarté R, editor. Ingredients in meat products: Properties, functionality, and applications. New York: Springer Science + Business Media. R. Tarté 17 Aug 2016 30
Ingredients from Edible By-Products Collagen Family of insoluble fibrous proteins found in all multicellular organisms; one of the most abundant proteins in nature Most abundant protein in mammals 25 30% of total body protein 1 2% of bovine skeletal muscle 4 6% of high-connective tissue muscles Major component of skin, bone, cartilage, tendon, blood vessels, basement membrane (endomysium), and teeth Rod-shaped molecule approx. 300 nm in length and 1.5 nm in diameter. Basic subunit: tropocollagen (mol wt 300 kda) Three helical polypeptide α-chains (α1, α2, and α3) coiled around one another into a triple-stranded superhelix stabilized by hydrogen bonds R. Tarté 17 Aug 2016 31
Ingredients from Edible By-Products Collagen Unique amino acid (AA) composition and sequence. 33% glycine 12% proline 11% hydroxyproline 11% alanine No tryptophan Contains unusual AAs 3-hydroxyproline, 4-hydroxyproline, and 5-hydroxylysine Chain has three amino acid residues per helical turn, with every third AA being glycine. R. Tarté 17 Aug 2016 32
Ingredients from Edible By-Products Collagen Properties Sources include skin, hide, bone, offal, and skeletal muscle Addition to meat products As a constituent of high-collagen meat raw materials Typically high-collagen tissues, such as skeletal muscle connective tissue, beef hides, pork skins, and tripe In concentrated form as a direct additive. Has been concentrated from bone (as bone collagen extract), beef hides, pork skins, and skeletal meat connective tissue Physical extraction and/or concentration of collagen usually involves particle size reduction of collagen or high-collagen materials by cutting, grinding, flaking, milling, or a combination of these R. Tarté 17 Aug 2016 33
Ingredients from Edible By-Products Collagen Applications Raw (high-collagen raw materials) Collagen triple helix begins to unravel, shrink and dissolve at 60 65 C, which may cause disruption of the myosin gel in comminuted meat products To avoid this, limit high collagen trimmings to 2 3% (especially from older animals), avoid excessive chopping, increase ph and ionic strength, cook in stepwise manner R. Tarté 17 Aug 2016 34
Ingredients from Edible By-Products Collagen Applications As added ingredient Research has focused on its extraction from various sources (species, anatomical locations) and by various means, and on its application in various types of meat products Various commercial forms of functional concentrated collagen ingredients can be made by low-temperature rendering systems Have been used I whole muscle and comminuted products Have been shown to increase cook yield, reduce expressible moisture and help reduce package purge Commercial forms may differ from each other, so TEST! R. Tarté 17 Aug 2016 35
Ingredients from Edible By-Products Gelatin Heat-denatured, partially hydrolyzed form of native, insoluble collagen. Amorphous mixture made up primarily of three types of free chains: α monomers (mol wt 100 kda) β dimers (mol wt 200 kda) γ trimers (mol wt 300 kda) Denaturation temperature of collagen varies by species and hydroxyproline content R. Tarté 17 Aug 2016 36
Ingredients from Edible By-Products Gelatin Commercial gelatin is obtained primarily from raw materials rich in type I collagen Pork skin and bones, beef hides and bones, calf skin Through very controlled stepwise process collagen is hydrolyzed followed by heating to denature the molecule to gelatin Types of gelatins Type A (isolectric point = ph 6 9) Obtained by mild acid pretreatment of physiologically young collagen (e.g., pig skins), which have high proportions of acid and heat labile cross-links Type B (isoelectric point = ph 4.8 5.2) Obtained by severe alkali pretreatment of the more highly cross-linked collagen from bone and cattle hides R. Tarté 17 Aug 2016 37
Ingredients from Edible By-Products Gelatin Commercial gelatin extracts are mixtures that contain not only α, β, and γ chains, but also other larger (up to mol wt 10 6 ) and intermediate size molecules as well Properties dependent on spectrum of molecular species and are affected by: Changes in the manufacturing process Nature of starting raw materials Type A gelatins are higher in lower molecular weight chains than type B Decrease in mol. wt. gel strength and viscosity R. Tarté 17 Aug 2016 38
Ingredients from Edible By-Products Gelatin Gelatin hydrolysates Obtained by controlled enzymatic hydrolysis of gelatin solutions to reduce the protein s molecular weight to a desired range Properties similar to gelatin except that, due to their lower molecular weight, they are more easily dispersible in cold water and do not gel at regular processing temperature R. Tarté 17 Aug 2016 39
Ingredients from Edible By-Products Gelatin Properties Incomplete protein: deficient in methione and devoid of tryptophan Excellent functional properties Gelling, melting (melts at <35ºC), stabilization, film-forming, texturizing, and water-holding Gels are thermoreversible Applications Aspics, canned hams and canned sausages. Have been proposed as external coatings to protect meat against color loss, aroma deterioration and purge losses GRAS status in U.S., so no maximum allowable level R. Tarté 17 Aug 2016 40
Ingredients from Edible By-Products Stocks and Broths High-protein (up to 94%) products Derived from: Liquid stream of low-temperature rendering of soft materials such as meat lean and fatty trimmings, pig skins, and poultry skins, or High-temperature rendering of soft materials or hard materials such as edible bones Collagenous in nature R. Tarté 17 Aug 2016 41
Ingredients from Edible By-Products Stocks and Broths Applications Bases for meat and reaction flavor manufacturing Protein sources and flavor enhancers for processed meat products Use in sausage products to increase the protein content Can act as stabilizers, emulsifiers, and binders, although that is not usually their primary purpose when added to processed meat products In U.S. ingredients such as dried stocks, dried broths, and meat extracts must be designated as dried (species) stock, dried (species) broth, and (species) extract (e.g., dried chicken stock, dried beef broth, pork extract, etc.) R. Tarté 17 Aug 2016 42
Ingredients from Edible By-Products Hydrolysates and Flavors Obtained from meat by-products such as bone residues, mechanically separated meat (MSM), bone cakes from mechanical separation, trimmings, blood plasma and red blood cells among others, meat (e.g., myosin and collagen) Chemical or enzymatic hydrolysis Properties such as emulsion stability, viscosity, and gel-forming ability decrease as degree of hydrolysis increases As DH increases, the flavor contribution of protein hydrolysates increases, primarily due to the presence of low-molecular weight flavor components (e.g., amines, amino acids, and small peptides) and flavor precursors (e.g., nucleotides and organic acids) R. Tarté 17 Aug 2016 43
Ingredients from Edible By-Products Hydrolysates and Flavors Choice of meat protein hydrolysate dictated by specific functional properties desired for each particular application and may also be limited by commercial availability In U.S. hydrolyzed protein of slaughtered animal species and tissue of origin, other than gelatin, must be indicated, e.g., hydrolyzed beef plasma, hydrolyzed pork stock, and hydrolyzed pork skin R. Tarté 17 Aug 2016 44
Ingredients from Edible By-Products Blood-Derived Proteins Blood fractions 60 80% Plasma 20 40% Cells (mostly red cells, with smaller amounts of white cells and platelets) Deficient in essential amino acids methionine and isoleucine Composition of blood and of its major fractions Blood fraction Protein (%) Moisture (%) Whole blood 17 18 75 82 Plasma 6 8 90 92 Cells 34 38 60 62 Dried plasma 70 95 5 10 R. Tarté 17 Aug 2016 45
Ingredients from Edible By-Products Blood-Derived Proteins Blood Plasma Protein (BPP) Functional properties attributed to its albumin, globulin, and fibrinogen content Good gelation, emulsification and solubility Gelation Strong, irreversible gel at protein concentrations of 4 5% when heated to at least 70 C Increasing temperature to 90 92 C will result in an even firmer gel Suitable for products subjected to high temperatures (e.g., canned) Gelation temperature, hardness, elasticity and water holding increase with increasing ph Emulsification Improve emulsion stability, texture, juiciness and peelability Useful in comminuted products R. Tarté 17 Aug 2016 46
Ingredients from Edible By-Products Blood-Derived Proteins Blood Plasma Protein (BPP), cont. Solubility Very soluble over ph 5.0 8.0 Ideal binder for meat products where solubility is critical, e.g., injected products R. Tarté 17 Aug 2016 47
Ingredients from Edible By-Products Blood-Derived Proteins Major plasma proteins and their basic properties 1 Protein Plasma protein (%) pi Molecular weight (kda) Serum albumin 56 4.8 4.9 69 α 1 -Globulins 5.3 2.7 4.4 44 435 α 2 -Globulins 8.4 3.6 5.6 41 20,000 β-globulins 11.5 3.6 5.9 80 3,200 γ-globulins 15 5.8 7.3 100 160 Fibrinogen 0.6 340 Adapted from: Gorbatov (1988); Howell (1992). 1 Protein levels vary with animal species and age. Source: Tarté R. 2009. Meat-derived protein ingredients. In: Tarté R, editor. Ingredients in meat products: Properties, functionality, and applications. New York: Springer Science + Business Media. R. Tarté 17 Aug 2016 48
Ingredients from Edible By-Products Blood-Derived Proteins Plasma Protein Fractions Plasma can be further fractionated into its major constituents albumin, globulins, and fibrinogen Precipitation and removal of fibrinogen leaves behind serum, which can then be further fractionated into albumin and globulins High degree of synergy between them In U.S. blood plasma is permitted in meat products R. Tarté 17 Aug 2016 49
Ingredients from Edible By-Products Blood-Derived Proteins Plasma Transglutaminase (TGase) Blood clotting Factor XIII (Ca 2+ -dependent) Can be used to modify texture and improve yields Appropriate substrate should be added to improve reaction, maximize TGase effectiveness and reduce usage level Can be used to bind uncooked meat pieces together Can be used to improve the texture of processed meats, alone (via cross-linking of meat proteins) or in combination with other non-meat proteins added to the system, such as soy protein or casein In U.S. permitted at up to 10%; words Formed with Beef Fibrinogen and Thrombin must appear either in the product name qualifier (at usage levels of less than 7%) (at usage levels of 7 10%) or in the product name R. Tarté 17 Aug 2016 50
Ingredients from Edible By-Products Blood-Derived Proteins Transglutaminase-catalyzed crosslinking reaction O O R C NH2 + H2N R R C NH R + NH3 Glutamine Lysine ε-(γ-glutamyl)lysyl isopeptide bond R. Tarté 17 Aug 2016 51
Ingredients from Edible By-Products Blood-Derived Proteins Food protein substrate specificity of TGases of different origin 1 Pig erythrocyte TGase Degree of cross-linking 2,3 Bovine plasma TGase Bacterial TGase Substrate DTT + DTT DTT + DTT DTT + DTT α-lactalbumin ± ± + ++ β-lactoglobulin ± ++ Bovine serum albumin + + ++ Casein ++ ++ ++ ++ ++ Hemoglobin ± ± ± ± Myosin ++ ++ ++ ++ Glycinin ++ ++ ++ `Source: de Jong, Wijngaards, Boumans, Koppelman, & Hessing (2001). 1 Experimental conditions: 37 C; ph 7.5. 2 Symbols: ( ) no cross-linking; (±) slow cross-linking; (+) moderate cross-linking; (++) fast crosslinking. 3 DTT: Dithiothreitol; promotes unfolding of the protein chain by reducing disulfide bridges. R. Tarté 17 Aug 2016 52
Ingredients from Edible By-Products Blood-Derived Proteins Hemoglobin and Red Blood Cells (RBCs) 70% of total blood protein is hemoglobin Limited use in meat products due primarily to the dark color and off-flavors they impart. Can be used as color enhancers In U.S., blood is permitted in products such as blood sausage, blood pudding, blood soup, and in beef patties, as long as a qualified product name is used (e.g., Beef and Blood Patties or Beef Patties with Blood ). Must always be declared in ingredient statement. R. Tarté 17 Aug 2016 53
References Aberle ED, Forrest JC, Gerrard DE, Mills EW. 2012. Principles of meat science. 5th ed. Dubuque (IA): Kendall Hunt. Chapter 16, By-products of the meat industry; p. 351 365. Labudde RA, Lanier TC. 1995. Protein functionality and development of bind values. Proceedings of the 48th Annual Reciprocal Meat Conference; 1995 Aug 20 25; San Antonio, TX. Chicago (IL): American Meat Science Association. p. 59 68. Liu D-C, Ockerman HW. 2001. Meat co-products. In: Hui YH, Nip W-K, Rogers RW, Young OA, editors. Meat science and applications. New York: Marcel Dekker. p. 583 Pearson AM, Dutson TR, editors. Edible meat by-products. London (UK): Elsevier Applied Science. Saffle RL. 1966. Linear Programming Meat Blending. Publication No. E20-0161-0. White Plains (NY): IBM. Tarté R. 2009. Meat-derived protein ingredients. In: Tarté R, editor. Ingredients in meat products: Properties, functionality, and applications. New York: Springer Science + Business Media. R. Tarté 17 Aug 2016 54