The Possibilities of Protein

The Possibilities of Protein
by Elizabeth Srejic

Forming the basis of all biomolecules, proteinderived from the Greek word protosor foundationis found in everything from hair to insulin.Consumption of highprotein functional foods ensures an adequate supply of basicbuilding blocks useful for basic nutritional insurance to competitivebodybuilding, and provides satiety helpful in weight management.

Proteins, a widely occurring class of natural polymer molecules, form themajor structural components of cells and act as components of enzymes involvedin cellular reactions. All protein molecules, which are the largest of allnaturally-occurring molecules, are comprised of polypeptide chains, whichinclude specific combinations of amino acids, 20 basic building blockscontaining both amino and carboxylic acid functional groups. The number of aminoacids in proteins may range from two to several thousand.

The primary structure of a protein refers to its specific sequence of aminoacids, which determines the proteins functionality. A proteins secondarystructure is defined as its specific geometric shape, produced by intramolecularand intermolecular hydrogen bonding of amide groups. Tertiary structure is thegeometric shape assumed by a protein as determined by a variety of bondinginteractions between the component amino acids. And a proteins quaternarystructure involves clustering of several individual peptide or protein chainsinto a final specific shape.

The two major categories of proteins with quaternary structure includefibrous and globular. Fibrous proteins include keratins found in hair, skin andnails, muscle fibers and clotting agents in the blood, and are composed ofcoiled alpha helical protein chains with a range of other coils analogous tothose found in a rope. Globular proteins, comprising insulin, hemoglobin, andmost enzymes, may consist of a combination of the above varieties of structuresand are clumped into a spherical shape.

Beyond its basic and necessary utility as a building block of all tissue,protein is most valued as a functional food for its ability to producesatiety,^1,2 promote retention of lean body mass (especially during weight loss),^3,4,5,6 modulate postprandial blood glucose^7,8,9,10 and boost bone mineral density (BMD).^11,12,13 Protein ingredients commonlyused in nutritional products and functional foods are primarily derived fromsoy, whey, casein, egg and fish, although newer ingredients such as colostrumand rice protein are gaining recognition in the marketplace. Each of thesevarieties has specific advantages and disadvantages determining theirsuitability for a range of applications.

One extremely popular protein source used in functional foods is soy protein,which provides a diverse portfolio of research-backed health benefits.

One of soy proteins strongest attributes is its potential role inimproving risk factors for cardiovascular disease, according to an AmericanHeart Association (AHA) science advisory.¹⁴ For example, consumption of soyprotein has been shown to lower cholesterol.^15,16,17,18 In fact, in October1999, the Food and Drug Administration (FDA) approved a health claim for use onlabels of soy protein-based foods to tout their heart-healthy benefits; theagency based its decision partially on evidence from 27 research studiesindicating soy protein may lower serum levels of total cholesterol (TC) andlow-density lipoprotein (LDL) cholesterol.¹⁹ Another cardiovascular benefitafforded by soy protein is reduced blood pressure, according to various in vivostudies.^20,21,22,23 A recent study published in Nutrition showed intakeof soy protein reduced several cardiovascular risk factors including TC and LDLcholesterol, blood pressure and Framingham risk assessment for coronary heart disease in postmenopausal women.24

Soy protein may also benefit bone health by inhibiting fracture orosteoporosis, or increasing BMD, according to numerous rodent and human studies.One such study, from the Vanderbilt University School of Medicine, Nashville,found an inverse relationship between consumption of soy foods and the risk offracture among ²⁴,403 postmenopausal women who had no history of fracture or cancer.²⁵ Further, an Iranian study found soy protein consumption produced beneficial effects on bone metabolism indicators, leading the researchers topropose soy protein may have a preventive role in bone resorption, therebypreventing osteoporosis.²⁶ And a University of Illinois at Urbana-Champaignstudy conducted on 66 postmenopausal women found administration ofhigh-isoflavone soy protein produced significant increases in BMD at the lumbar spine.²⁷

Soy protein has been shown to provide antioxidant advantages beyond those of its functional protein ingredient cousins.^28,29,30,31 These effects may be of particular benefit to athletes, who rely on proteinsupplementation as part of their training regimes and are at high risk foroxidative damage stemming from exercise. A study from Ohio State University,Columbus, compared the effect of consumption of soy and whey protein bars inathletes and found both the soy and whey groups showed a gain in lean bodymass.³² However, the whey group, but not the soy group, showed a potentiallydeleterious posttraining effect on two antioxidant-related parameters, leadingthe researchers to conclude soy and whey protein bars both promoted exercisetraining-induced lean body mass gain, but the soy had the added benefit ofpreserving two aspects of antioxidant function. And a study on the impact of soyprotein consumption versus whey protein intake on total antioxidant status of 20healthy, athletic, college-aged males found supplementation with 40 g/d soyprotein (as Supro®, from The Solae Co.) in conjunction with a strenuoustraining program produced an increase in total antioxidant status as well asreduced serum levels of myloperoxidase, an indicator of oxidative stress.³³

Soy proteins antioxidant capabilities may also implicate the ingredient asan anti-cancer therapy. According to a recent metaanalysis from The Solae Co.published in the International Journal of Cancer, the results of twocohort and six case-control studies may indicate a role of soy protein consumption against prostate cancer.³⁴ And a 2006 study published in Cancer Research showed soy isoflavonesinhibited markers of breast cancer in a postmenopausal primate model, leadingresearchers to conclude dietary soy isoflavones may alter estrogen receptorsignaling and induce selective antagonistic effects in the breast.³⁵

Due to its heart-healthy, anti-osteoporotic and anti-breast cancer effects,use of soy protein may be ideal in functional foods aimed at women, who are atparticular risk for health problems in these areas, especiallly duringmenopause. Soy protein may further benefit menopausal women due to itscontroversial ability to reduce hot flashes,³⁶ an effect possibly produced bythe compounds natural isoflavone content. Among men, however, soy protein maybe a less popular protein source, in spite of the ingredients purportedeffects against prostate cancer; although soy proteins isoflavone contentfunctions as a selling point among women, it repels some male end users who fearsoy isoflavones could cause estrogen-like effects. While not all soy proteins on the market contain isoflavones, soy proteinalso may be regarded as a womans protein by men because of the ingredientspopularity among menopausal women.

In the realm of weight loss, soy protein may provide specific benefits beyondother protein sources. A study from the University of Kentucky, Lexington,comparing the efficacy of meal replacement beverages in producing weight loss,found a soy protein-based beverage produced greater weight loss over a 12-weekperiod than a milk protein-based beverage did.³⁷ According to a recent studypublished in Atherosclerosis, such effects may be due to soy proteinspossible ability to increase endogenous production of adiponectin, anadipose-specific plasma protein with an inverse relationship to body weight, especially visceral adiposity.³⁸

Soy protein, which is extracted from soy bean cotyledons, is the idealvegetable protein due to its comprehensive amino acid profile, according to BobRasmus, sales director with Archer Daniels Midland (ADM) Food Ingredients. Ofall vegetable protein sources, soy has the highest PDCAAS [protein digestibilitycorrected amino acid score], which rates the inclusiveness and ratios of aproteins amino acid profile, he said.

In general, the best applications for soy protein include crispy-type energybars, where soy is delivered as a crisp, an ingredient available in differentprotein grades and manufactured by twin screw extrusion, a process originallydeveloped for plastics in the toy industry, according to Grant Gengel, directorof marketing with Nuvex. Thats where the texture and shelf-life advantagesare put to best use, he said. However, he said soy protein crisps do notfunction well in all applications: Generally, baking is not crisp-friendly.The crisps tend to hydrate and get soft and soggy.

Another advantage soy protein has over other protein sources is itscost-effectiveness. According to Deborah Schulz, market development manager withCargill Health & Food Technologies, soy protein is usually available at halfthe cost of whey protein. Milk protein prices are at an all-time high, shesaid. Were finding increasing numbers of customers are expressing interestin replacing other protein sources with soy protein.

In spite of its health benefits and attractive cost, however, soy proteinpresents certain problems in formulation.For example, one wellknown drawback ofsoy protein use is the ingredients purported beany flavor. According toGwen Bargetzi, marketing director with Hilmar Ingredients, this undesirableflavor note is detectable in certain formulations.Soys notoriously beanytaste is fine in some applications; however, a strong taste can be quite detrimental in others with a moretransparent flavoring system, she said.Vanilla comes to mind as beingparticularly sensitive to any taste contributed by proteins.

One solution to soy proteins beany taste is the use of highly purified andconcentrated soy protein isolates, which are largely tasteneutral. Historically, some isolates continued to have flavor challenges, saidSchulz. However, the technology to solve this problem has been developed overthe years, and the soy protein isolates are now the cleanest [mosttasteneutral] proteins available.

As with other protein isolates, soy protein isolates are useful for veryhigh-protein applications as they consist of 90-percent or more protein, whichallows flexibility for formulating other ingredients and can produce thicktextures. According to Rasmus, soy protein isolates are available in a widerange of different grades, allowing for versatility in formulation. Some are hydrophilic, some are hydrophobic, they all have differentviscosities, and so forth, he said. These different attributes allowflexibility across a range of applications. However, Rasmus noted the tendency of soy protein isolates to gel, or congeal, canpreclude them from use in beverages. While soy proteins texture can beefficacious for meat and cheese analogues, the last thing youd want to put ina sports drink is something with properties like Jell-O®, he said. Since soy protein isolates tend to gel, they must be kept withintight, specific parameters to work with specific machinery. In the case ofextrusion, soy protein can gum up the machinery if it doesnt contain theright ratios of protein and other components. In the case of bread manufacture,the dough is often pumped between machines; the addition of soy protein can make the dough too heavy and difficult topump.

Gengel added soy proteins proclivity to congeal can also preclude theingredient from use in energy bars; however, he further noted this problem isfrequently solved by the use of soy protein crisps. Soy protein crisp is usedmainly because using soy protein isolate in its native state, along with othernutrients that youd want to include in an energy bar, causes the protein tocongeal, which makes the bar hard and shortens the shelf life dramatically,he said. However, when the protein is delivered as a crisp, the heat and theshear in the manufacturing process are sufficient to partially denature theprotein, rendering it virtually inert, producing a soft texture and extendingthe shelf life.

A limitation of soy protein crisp is its protein level, which, according toGengel, normally cannot exceed approximately 80 percent. Once you get pastabout 80 percent, the protein becomes un-extrudable because of the by-productsof the protein denaturing process; it tends to clog up the equipment.

According to Rasmus, another drawback of soy protein is its naturallyoccurring oils must be removed during processing, usually through use of asolvent. Once a solvent is used, the product can no longer be consideredorganic. Also, heat generated by the expeller pressing process used to removethe oil can negatively change the nature of the soy protein, causing it to loseits solubility, which limits the proteins functionality. He added the qualityof the finished product can hinge on how well the solubility of the soy proteinwas preserved during processing.

Rasmus further noted the functionality of soy protein is limited tonon-liquid applications as the ingredient tends to precipitate out of solutions.A better choice for beverages is whey protein, he said, which is soluble acrossthe pH range. Soy is comprised of four major proteins, yielding an averageisoelectric point of 4.5, he said. When you put it into an acidic state,that protein will become solid again and precipitate out. Whey, on the otherhand, is easier to work with in an acid environment.

Although soy protein does have certain limitations in formulation, itsinclusive suite of health benefits still distinguishes it as an excellent choiceamong the protein sources, particularly its animal-based counterparts, accordingto Cathy Bloom, senior sales representative with DNP International. As a purevegetable soy protein, soy protein has fewer side-effects than animal protein,she said. It is lactose free and meets or exceeds the essential amino acidrequirements for adults and children.

Got Dairy?

Beyond the plant kingdom, dairy milk is a staple source for a wide range ofprotein ingredients, including whey and casein. The nutritional value of milkproteins is nutritionally advanced to that of other protein sources, saidMargaret Greaney, marketing services manager with Kerry Dairy Proteins, whichproduces Ultranor TNT, a range of milk proteins designed to enhance texturaland organoleptic properties of nutritional bars by preventing hardness duringshelf-life. The protein efficiency ratio (PER) of milk proteins is superior to other traditional protein delivery systems. Furthermore, our Ultranor milk proteinspossess a clean milk color and flavor which requires no masking in the finishedproduct.

Dairy-derived whey protein is a widely used milk protein ingredient. As an isoflavone-free product, whey protein may be a more popular proteinsource among men than women. Further, as whey protein provides a rich source ofbranched-chain amino acids (BCAAs), it has been particularly popular amongathletes and body builders. When combined with a resistance training program,whey protein has been shown to increase muscle mass and muscle strength,^39,40enhance muscle glycogen uptake,⁴¹ heighten oxygen-carrying capacity of theblood, and encourage quicker recovery from muscle fatigue, promoting increasedtraining efficiency.⁴² Whey proteins BCAAs are particularly conducive tomuscle growth and regeneration as they increase the rate of protein synthesisand decrease the rate of protein degradation in human muscle.^43,44,45

In the realm of weight loss, whey protein may provide benefits beyond soyprotein- or carbohydrate-based diets, according to new research presented at the2006 Experimental Biology meeting in San Francisco by researchers from theBeltsville Human Nutrition Research Center at the U.S. Department ofAgriculture. In the study, 90 free-living, overweight and obese (BMI greaterthan 28 and less than 38) individuals were randomized to receive 60 g/d wheyprotein, soy protein or carbohydrate for six months. Test subjects who consumedsupplemental whey protein for six months weighed less and had less body fatcompared to individuals who consumed a supplement based on soy protein orcarbohydrate. Further, while body weight did not differ between the whey and soygroups, the whey group lost more inches around the waist than the groupconsuming soy protein.

Whey protein may also boost immune response in athletes whose immunity has been compromised by strenuous, prolonged exercise.⁴⁶ Research indicates these benefits likely extend beyond athletes to benefit anyone with compromised immunity.^47,48,49,50

According to Bargetzi, whey protein is suitable for a wide range ofapplications. Our whey proteins are quite dexterous and can be used in arrayof applications from nutritional bars and baked goods to dairy (e.g., yogurts,ice creams), savory and meat applications, she said. If I had to chooseone specific area that maximized the contributions of whey protein, Id choosea food bar [due to the texture whey provides]. One reason for wheys broad functionality is its superior solubility acrossthe pH range and ability to mimic the behavior of other protein sources,Bargetzi added. [In contrast to acid-stable whey, other protein sources] arepH sensitive and will precipitate at the isoelectric point of pH 4.6, shesaid. Heat and acid stability are especially helpful in acid beverages, suchas juice-based drinks, because other protein sources like caseinate are notstable and will flocculate or fall out of the system. [With regard to sharedfunctionalities], whey proteins can be used as an alternative when egg or milkproteins are not desirable, she said. Another benefit of wheys functionality in lower-pH applicationsis its translucence in acidic beverages, added Simon Leitch, business manager,protein beverages, with Fonterra, which is developing high-protein shots andjelly drinks. [In contrast to various other protein ingredients, whey proteinmaintains a] clear appearance at acidic pHs, he said.

Beyond its wide range of applications and texture, another major benefit ofwhey protein is its taste, which, according to Steve Dott, vice president ofGrande Custom Ingredients, distinguishes this protein from its counterparts. Byfar, whey protein provides the best taste of all the protein sources, hesaid.

Milk proteins definitely provide the best taste, making them a clearchoice over other protein sources, agreed Craig Air, technical servicesmanager with Erie Foods.

However, optimal taste and wider functionality comes at a higher price; wheyprotein ingredients are often twice as expensive as soy ingredients, accordingto Gengel.

The real drawback with whey protein, in spite of its many positivesitsthe best-tasting protein source out there, in my opinionis the cost is verysignificant, he said.Were charging about $4/lb for it, which reallylimits the applications; it could sink projects, economically. Gengel saidNuvex Ingredients solves this problem with a soy- and wheat-protein hybrid,SuperSaver 60, a 60-percent protein soy protein crisp available at asignificantly lower cost than most whey protein ingredients. Normally, thecombination of soy and wheat would be hard as buckshot, but we found a way togive it a crispy texture, he said. Weve been hearing a lot fromcompanies that wanted to introduce products like [whey protein-based] proteinbars, but couldnt find a high-protein crisp that fit their economic model,he said. With the introduction of the Super Saver 60 protein crisp, which issuitable for bars, breakfast cereals and baked goods, we expect to be able toprovide the protein punch theyve been looking for at a price that makes itall affordable.

Gengel added another reason to avoid whey protein is that it is difficult toextrude. It denatures at a fairly low temperature, so its constantlyclogging the machinery, he said.

Casein, a tasteless, odorless protein precipitated from milk by rennin, isanother beneficial protein source. As it may improve cardiovascular training,decrease epididymal fat tissue and increase lean body mass,⁵¹ casein may promotepositive results in resistance training programs. Further, casein producessimilar increases as whey protein in muscle protein net balance and synthesis,despite different patterns of serum amino acid responses between the twoingredients.⁵² However, clinical trials comparing the efficacy of the twocompounds have shown mixed results with regard to lean body mass and muscleglycogen uptake. One such trial, a randomized, prospective 12-week study onoverweight policemen conducted at Brigham and Womens Hospital, Boston,compared changes in body composition produced by supplementation with casein orwhey protein plus exercise and a hypocaloric diet, and found test subjectssupplemented with casein experienced greater gains in strength and lean bodymass than individuals given whey.⁵³ The researchers concluded the disparity inresults between groups was likely due to improved nitrogen retention and overallanti-catabolic effects produced by specific peptide components of the casein hydrolysate. Conversely, a Japanese study found whey protein superior to caseinin promoting glycogen uptake in skeletal muscle of exercise-trained rats.⁵⁴

In comparison to soy protein, casein has shown better results in buildinglean muscle mass than its botanical cousin has in a handful of clinical trials.One such study, conducted at Maastricht University in the Netherlands, comparedthe efficacy of casein and soy protein with regard to the ingredientsmetabolic effects in healthy human subjects and found casein produced greaternet protein synthesis in test subjects than soy; in addition, a significantlylarger portion of soy protein than casein was degraded to toxic urea within the body.⁵⁵ Similarly, another study out of Maastricht University measuring net proteinretention and amino acid and urea kinetics in gut, liver and muscle of pigsgiven casein or soy found casein promoted greater net protein synthesis than didsoy, while soy protein produced higher levels of urea.⁵⁶

Other advantages of casein include its lower lactose content than wheyprotein, a boon to end users with lactose intolerance, as well as its slowerabsorption rate than soy or whey proteins, which could be beneficial tobodybuilders seeking a more sustained supply of amino acids.

With regard to caseins facility in formulation, the ingredient can befurther processed to produce a caseinate, which is more soluble than itspredecessor, and can be manipulated to control viscosity. We make thecaseinate by adding an alkali, which makes the casein more soluble inliquid, he said. The ingredient can be processed to give it higherviscosity; a sodium caseinate has higher viscosity than a calcium caseinate, forexample. Air added that casein ingredients, such as sodium caseinate,generally have good emulsification properties and can be agglomerated andinstantized to be more dispersible in a liquid.

Beyond the Norm

Colostrum is a source of dairy-derived protein growing in popularity. Itsmain advantage over other protein sources is its content of antibodies, whichhave been shown to boost immunity, according to a number of clinical trials andreviews.^{57,58,59,60,61,62} Although derived from a dairy source, colostrum isdistinctly different from milk or casein or whey protein preparations, becauseof the high levels of these immune and growth factors present in colostrum,said David Evans, technical director, and Barry Ritz, technical sales consultant- East coast, with La Belle Inc. In many ways, colostrum can be considered natures first functionalfood.

According to Evans and Ritz, La Belles bovine colostrum is processed bycollecting excess bovine colostrum from Grade A dairies; the ingredient is thenpooled, thermally treated by a proprietary lowtemperature process to protect thedelicate protein fractions, concentrated, and gently spray-dried. Subsequently,all colostrum powder is analyzed for composition and purity, and assayed forbioactivity of immunoglobulins by radial immunodiffusion (RID) analysis. Theingredient is available in different grades of protein and immunoglobin content,and in special forms for markets with lactose and other dairy sensitivities. Evans and Ritz added the product is suitable for a wide range of applicationsas it has a balanced amino acid profile, and a prime target market is athletes,who require both extra dietary protein and immunity.

When athletes are doing extra training to get ready for a competition,their immune systems tend to get depressed and it is not unusual for them to getsick; colostrum contains immunoglobulin proteins and cytokine fractions thatsupport the immune system and help the body thrive, they said. La Belle produces Intact®, a powdered colostrum supplement for athleteswith product-specific research on performance and recovery benefits.

According to Evans and Ritz, colostrum has been available historicallythrough a variety of delivery methods. Traditionally, colostrum has beenpositioned in the human market as a capsule or chewable tablet, they said.Manufacturers have been including colostrum in the formulation of functionalfoods and nutrition/protein bars. There are also some powder mixes and liquids on the market. More recently,there has been a rise of consumers interested in powders in order to obtainhigher doses of colostrum protein. We believe we are going to see moreapplications in the functional food markets and incorporation of colostrumproteins into more traditional health foods like orange juice and yogurt.

One consideration in processing colostrum is heat treatment, which can bedeleterious to the ingredients key components, they added. Some processorstreat colostrum proteins like milk proteins during production, they said. Exposingcolostrum proteins to the harsh chemicals and temperature extremes of milkprocessing destroy a lot of their effectiveness.

Beyond whey, soy, casein and colostrum, other typical protein ingredients aresourced from egg, fish and rice.

The avian egg is an important source of nutrients, containing all of theproteins, lipids, vitamins, minerals, and growth factors required by thedeveloping embryo, as well as a number of defense factors to protect againstbacterial and viral infection.⁶³ Further, several biological activities havebeen associated with egg components, including novel antimicrobial, anti-adhesive, immunomodulatory, anti-cancer,antihypertensive and antioxidant properties.⁶⁴ Before soy and milk-derivedprotein supplements and functional foods became widely available, eggs provideda standard source of protein for bodybuilders.⁶⁵ However, modern egg protein ingredients eliminate the fat and cholesterolnaturally present in eggs to yield a highly purified, complete protein source.Further, according to Karen Moss, food scientist with Henningsen Foods, eggproteins may have anti-hypertensive properties.

Chickens provide antibodies to the newborn chicks via the egg, saidEvans and Ritz. La Belle is engaged in a tremendous amount of research anddevelopment to provide avian egg protein products that are enriched in specificantibodies (patents and licensures pending). These specialized proteins can thenbe used to supplement humans and animals to target specific immune challenges.Such products are currently being tested in calves and goats, and La Belle is onthe verge of commencing a pre-clinical trial on the use of a specialized proteinproduct to protect dogs from parvo virus.

A delivery challenge associated with egg products is their sulfurous flavor.According to Moss, whose company produces EP-2, an egg white protein ingredientmanufactured using a proprietary, controlled enzyme hydrolysis of egg whiteprotein, hydrolysis can solve eggs flavor challenges, if executed correctly,and can even increase bioavailability of the ingredients key components. Veryfew protein products are hydrolyzed (broken down) due to the resultingoff-flavors, she said. Most proteins are sold intact in powder form.However, the controlled hydrolysis used to manufacture EP-2 results in peptideswith a mild, neutral flavor without the bitter taste usually associated withprotein hydrolysates. Also, the hydrolysis of egg white protein results ingreater bioavailability when compared to intact proteins, making the amino acidsin EP-2 easily digested. While the idea of hydrolyzed egg whites is not a brandnew concept, we believe EP-2 has found the correct balance between the benefitsof hydrolysis and flavor.

With regard to applications, Moss said the hydrolysis can prevent coagulationof proteins within egg protein ingredients, making them suitable for hot or coldbeverages; further, the process makes rehydration easier than it can be withintact protein ingredients. Schultz added another good application for eggprotein is baked goods due to the specific effects egg can provide, according toSchulz. Eggs have specific functionality in the baking area, she said. Theyreused frequently to provide aeration and whipping, which cannot be provided byother proteins such as whey or soy.

However, although egg protein works well in baking applications, it is notsuitable for extrusion due to the cost, Gengel noted. Weve done some experimental extrusion with egg and whey protein, hesaid. It made a wonderfully textured piece. Unfortunately, it was soexpensive that it was just prohibitive.

Fish protein, another complete protein source, is gradually gainingrecognition as a protein ingredient. According to recent research, fish proteinproduces an extremely low postprandial glucose and insulin response. Theseeffects could likely result in a more sustained supply of glucose as well asprolonged satiety. Researchers from Uppsala University in Uppsala, Sweden,administered three protein-rich meals based on soy protein, milk protein or fishprotein to healthy test subjects.⁶⁶ The insulin-to-glucose ratio was lower afterthe cod protein meal compared to the milk and soy protein meals at 120 minutes.Similar results were obtained in a rat study out of Laval University, Ste-Foy,Quebec.⁶⁷ Male Wistar rats were fed for 28 days with isoenergetic dietscontaining either casein, soy protein, or cod protein. Cod protein- and soyprotein-fed rats had lower fasting plasma glucose and insulin concentrationscompared with casein-fed animals.

One hydrolyzed fish protein ingredient is Seacure®, a 99.8-percent cod and0.2- percent rosemary extract ingredient from Proper Nutrition, producedutilizing a proprietary microorganism. According to Dee Eckert, director ofoperations for Proper Nutrition, fish protein provides a range of benefitsbeyond other protein ingredients. Seacure provides so many benefits to thebody because it is a highquality protein source, she said. Because Seacureis pre-digested during our manufacturing process, [its amino acid constituentsare] immediately absorbed and assimilated by the body. In addition, recentresearch conducted in England indicates that the peptides found in Seacure havebeen shown to have healing properties.

According to Eckert, fish protein can be delivered in numerous forms, such aspowders or chewable tablets, and is suitable for a wide range of applications.

Seacure may be incorporated into any finished product, unless [the enduser] is allergic to cod, she said. There are no contra-indications intaking Seacure with any other dietary supplements, medications or vitamins.

In spite of their wide applicability, one delivery challenge with fishingredients is the issue of heavy metal content. However, Eckert said each batch of product can be independently assayed for content ofmercury and other heavy metals, as is the case with her company. She addedunpleasant fishy odors are another challenge common to fish protein ingredients.Since Seacure is a fish protein concentrate, our product does have a fishodor, she said. This is a challenge that we have faced for over 11 years.After many failed attempts to mask the smell, we discovered that by chillingSeacure, which does not decrease the efficacy of the product, the smelldissipates.

Rice protein, derived from the grains endosperm, is another protein sourcegaining momentum in the protein ingredient market. According to Gil Bakal,managing director of A & B Ingredients, the main benefit of rice protein isthat the ingredient is hypoallergenic. Rice protein is one of the onlyhypoallergenic protein sources known, he said. It is good for people whohave allergies to soy, milk or meat proteins, or who dont want to use theseproteins.

Bakal said the ingredient is processed by separating the carbohydrate andprotein fractions from the endosperm; the protein is isolated and concentrated.The protein can also be treated with enzymes to improve its solubility, which inturn determines the different grades of product available, he added.

Our standard protein is a concentrate, which is an insoluble product,he said. But we also offer hydrolysates, which are soluble. The degree ofsolubility determines the grade.

Solubility can determine rice proteins suitability for specificapplications, Bakal added; ideal applications for rice protein include bakedgoods, often as a complementary protein source blended with otherproteins. However, he noted rice protein does not function well in beverages asit tends to precipitate out of the solution: Were still working on ways tomake the protein more soluble while retaining flavor and cost effectiveness.

Selection Tactics

To select the appropriate protein for a functional food or beverage protein,manufacturers should consider issues such as functionality, delivery method,nutritional value, cost structure and target market to choose a protein ideallysuited for the desired end product. In addition, consider the choice of suppliercarefully, based on a suppliers expertise, reliability, cost and specificbenefits.

Since all proteins have different attributes, not all types of proteins canperform in all applications. Moreover, a major consideration in selecting aprotein is the ingredients functionality, according to Bakal. Differentproteins have different functional properties, he said. Theyll bind different amounts of water, thicken or coagulate,all of which play a role in formulation. Milk proteins, for example, can get toodry, which can necessitate the combination of proteins, rather than milk proteinalone, in formulation.

To provide specific functionalities, most companies offer several grades of aprotein product, each one suitable for particular applications, according toSchulz. Often, use of more than one type of protein is necessary to achievethe desired functionality, she said. For example, in the case of Prolisse [Cargills line of soy proteiningredients], the membrane filtration process we use to manufacture theingredient allows for several varieties with different attributes providingdifferent types of functionality.

According to Bargetzi, a good place to start is to ask for a suppliersinput on which protein ingredient best suits a proposed application. Thereare many protein products available and a good supplier will provide technicalsupport and advice to help shorten your development time,she said. Proteins are very different from each other; milk proteins aredifferent than plant proteins. Even within the milk proteins, each has its ownpersonality.

Bakal agreed all proteins have different attributes that must be taken intoconsideration when choosing a protein ingredient for a particular application.There are cleaner proteins, but all of them have a flavor, he said.Soy proteins have a beany note; milk proteins have a dairy note; egg proteinshave a sulfur note; rice protein has a grainy note. Each of them has theirflavorand color considerations.

The specific flavor notes of proteins often motivate manufacturers to blendvarieties, rather than using an isolated protein source in formulation,according to Rasmus. Proteins can work together in food systems, he said.You could pick just about any nutrition bar and see soy proteins and dairyproteins working side by side.

However, not all grades of proteins will work together, necessitatingformulation expertise, Rasmus cautioned. The structures of various proteinsdetermine how they fit together and act together in formulation; for example,solubility of various protein ingredients determines whether one will clump orseparate from the others.

One often overlooked consideration in selecting a protein source is theingredients allergic potential, which can exclude certain target markets,according to Bakal.

Almost all proteins are allergens, he said. Suppliers must helptheir customers select a protein thats safe for a specific target market.

Considerations in selecting a supplier include quality, price andreliability, as well as consistency between batches, according to Gengel.

According to Bargetzi, another consideration is the specific portfolio ofexpertise a supplier can provide. For example, she said Hilmar specializes inspecific formulation issues including heat and acid stability, gelling, barsoftening and texture improvement properties and molecular weight profiles forspecific nutritional needs. Always consider the competence and quality of support a supplier canprovide, she said. Its a measure of how much they are willing to investin their product line and their customer. Look at application knowledge,timeliness of response, sampling, market awareness, customer service and companyphilosophy. Does this supplier treat us like a transaction or an investment?

Certain suppliers provide services beyond formulation expertise andreliability, according to Schulz, whose company also helps its customers withmarketing. We can help a customer understand how trends in the consumermarketplace apply to the types of products Cargill brings to the table and howthose products fit with our customers products. We also have branding programsthat allow us to bring benefits to our customers.

Further, Rasmus stressed the importance of flexibility. A good vendorshould be able to tweak a product to fit a specific process, he said. Customershave different needs; a supplier should be able to customize a product to fit aspecific food program. In order to do this, a supplier should have extensiveexpertise across the range of proteins.

The protein ingredients market boasts an expanding range of wellresearchedofferings with a variety of different attributes and functionalities, andsuppliers are transcending basic roles by providing manufacturers with variousincentives, including formulation expertise, expanded product ranges andmarketing assistance.

For information on zein, a family of water-insoluble prolamine proteins derived from corn, and for a full list of references click here.