GB1575577A - Compositions containing metal chelates - Google Patents

Description

(54) COMPOSITIONS CONTAINING METAL CHELATES (71) I, HARVEY HAROLD ASHMEAD, of 719 East Center, Kaysville, Utah 84037, United States of America; a citizen of the United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is totbe performed, to be particularly described in and by the following statement:- Certain metals are known to be essential to the proper functioning of the body.

Calcium is present in the body in greater abundance than any other metal and is -found primarily in the bones and teeth but also plays an important part in blood clotting. Many enzymes require magnesium. Magnesium deficiencies lend to vasodilation and hyperirritability of the nervous system. Magnesium is not easily absorbed into the body and is largely excreted in the feces. Hence most magnesium salts are laxatives or cathartics.

Iron is essential in the formation of hemoglobin and in metabolic and respiratory functions of the body. Lack of iron absorption is a primary cause of anemia. In inorganic form very little iron is absorbed and most iron ingested is eliminated in the feces.

Copper is an important metal in the functioning of many enzymes and is associated with hemoglobin formation and enzyme functions. Again inorganic copper is excreted via the bowels.

Cobalt is a component of vitamin B12 and has been used successfully in the treatment of certain types of nutritional anemia.

Another essential element is manganese. Manganese deficiencies are essential to growth and virility. Manganese is also involved in activating several enzymes.

Again, manganese is largely excreted in the feces.

Zinc has been found to be essential in the actuation of enzymes relating to cell division and is a constituent of insulin. Excretion of zinc is largely through the digestive tract.

Molybdenum is another element found in certain enzymes.

Other trace metals such as chromium and vanadium are also thought to be essential.

All of the above metals are capable of existing in polyvalent form. By polyvalent is meant the metals may assume an ionic or oxidation state of +2 or higher. This assumes that copper will be in the cupric or +2 state.

Since, in general, these metals, as inorganic or organic salts, are absorbed with difficulty it would be desirable to find a formulation whereby these metals could be effectively assimilated into the body. Salts ionize in the gastric juices of the stomach and enter the small intestine, where most absorption takes place. The intestinal walls are lined with electrical charges which have a strong tendency to repel the positive metal cations while allowing the anions to pass through. The essential metals are thus discharged through the bowel after causing diarrhea. The anions passing through the intestinal wall often are excreted via the urine and often act as diuretics.

Various attempts utilizing organic salts have been made with limited success.

Chelates utilizing ligands formed from EDTA (ethylenediaminetetraacetic acid) and derivatives have also been utilized. Chelates formed from EDTA normally bind the metal so tightly that it is not made readily available to the body.

It would therefore be beneficial to prepare a formulation of a biologically essential metal in a form whereby the effects of the electrical charges of the intestinal lining of the metal were minimized and whereby the metal could be made available in a readily assimilable form.

In the past it has been known to utilize certain protein hydrolysates as chelating agents or ligands to increase the assimilation of metals into biological tissues. It has been found however that certain protein hydrolysates are poor ligands due to their size and sterochemistry. Long chain polypeptides when used as ligands do not form as strong a bond with a metal ion in chelate formation as do amino acids, dipeptides and tripeptides. It is therefore axiomatic that chelates formed from metals and long chain polypeptides are more easily destroyed in the acidic gastric juice of the stomach.

Protein hydrolysates is a term generally used for any form of hydrolyzed protein ranging from the above mentioned long chain polypeptide down to the basic protein building blocks, i.e. amino acids. These hydrolysates are commonly formed utilizing acidic or basic hydrolysis or a combination of both. Since many different amino acids are essential to the body there is a distinct disadvantage to the utilization of either form of hydrolysis. Acidic hydrolysis destroys the amino acids tryptophan, serine and threonine. On the other hand basic hydrolysis racemizes the amino acids into their D, L forms and destroys arginine threonine, serine, and cystine. Naturally occurring amino acids belong only to the L-series. Moreover acidic and basic hydrolytic processes require neutralization and this results in the formation of inorganic salts which often remain with the hydrolyzed product.

Chelates formed from biologically essential metals and protein hydrolysate ligands are referred to herein as metal proteinates.

It is an object of the present invention to provide a metal proteinate in a form that is readily assimilated into the body of a warm blooded animal.

Another object of the present invention is to provide a product that will increase the metal content in biological tissues on oral administration.

Also, an object of this invention is to provide metal proteinates as hereinbefore described in a sufficiently stable form that they will pass intact through the stomach of a warm blooded animal and be assimilated into the body through the intestinal walls.

According to the present invention there is provided a method of raising the level of biologically essential metals having a valency of +2 or greater in the tissues of warm blooded domestic animals which comprises administering at least one metabolically assimilable metal proteinates to said animals each said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

Also in accordance with the present invention there is provided a method for treating anemia in piglets which comprises administering a metal proteinate in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids, to a farrowing sow during the latter stages of pregnancy and during lactation.

Further in accordance with the present invention there is provided a composition for raising the level of biologically essential metals having a valency of +2 or greater in the tissues of animals, comprising a carrier and at least one metabolically assimilable metal proteinate each said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

In one embodiment of the present invention there is provided a bakery product containing a biologically essential metal having a valency of +2 or greater as a metal proteinate said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

In a further embodiment there is provided a cooking oil containing a stabilizing amount of at least one metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

Still further in accordance with the present invention there is provided an oil cooked edible food containing a biologically essential metal having a valency of or greater in the form of a metal proteinate wherein said metal proteinate is absorbed onto said food from the cooking oil and wherein said metal proteinate is a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

In yet another embodiment of the present invention there is provided a product comprising a meat or meat flavored vegetable derivative containing a biologically essential metal having a valency of +2 or greater in the form of a metal proteinate or a mixture of metal proteinates wherein each said metal proteinate is a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

In a still further embodiment of the present invention there is provided a seasoning salt or spice which has been fortified with metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

Also in accordance with the present invention there is provided a food product containing on the surface thereof a seasoning salt which has been fortified with at least one metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides, and naturally occurring amino acids.

Finally, in accordance with the present invention there is provided a food product comprising a sugar as the principal ingredient and containing a metal proteinate or mixture of proteinates wherein each said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

It has now been found that biologically essential metals having a valency of +2 or greater are more effectively administered to animals in the form of a chelate formed from naturally occurring amino acids or dipeptides or tripeptides thereof wherein the ligand to metal mole ratio is generally from two to sixteen. Preferably the mole ratio of ligand to metal will be between two and eight. Especially preferred are ratios between two and four. Each ligand will generally have a molecular weight which is from 75 to 750.

The ligands will advantageously be formed by the enzymatic hydrolysis of protein sources such as collagen, fish meal, meat, isolated soya, yeast, casein, albumin and gelatin. Enzymatic hydrolysis utilizing enzymes, such as trypsin, pepsin and any other protease may be used provided it is not detrimental to the formation of L-amino acids. Ligands prepared by enzymatic hydrolysis do not contain inorganic salts that ligands from basic or acidic hydrolysis may have.

However the use of ligands formed from acidic and basic hydrolysis may also be utilized but on a less preferred basis. The term "naturally occurring amino acids" as used herein also include synthetically produced amino acids having the same stero configuration and chemical structure as those which occur in nature. Proteins yield about twenty amino acids including glycine, alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, tryptophan, serine, threonine, aspartic acid, asparagine, glutamic acid, glutamine, lysine, arginine, histidine, cystine, cysteine, methionine, proline and hydroxy proline. A dipeptide is a combination of two amino acids with a peptide (-CO-NH-) bond and a tripeptide is a combination of three amino acids with two peptide bonds. The ligands bonded to a metal ion can be the same or different.

When making the chelates the shorter the chain length of the ligand the easier it is to form chelates and the stronger the chelation bonds will be. As used herein the term chelates and protein ate may be used interchangeably unless a non-protein derived ligand is referred to.

It is beneficial to first hydrolyze a protein source well so that the major portion of the hydrolysates will be amino acids, dipeptides and tripeptides. Thus, the subsequent formation of the metal proteinate or chelate can form a product that can be actively transported through the body tissues. Large protein entities such as metal salts of gelatinates, caseinates or albuminates must be broken down or hydrolyzed before transport can take place. It is believed that unhydrolyzed protein salts, in general, are unabsorbed from the intestinal walls. Therefore, in the present invention the protein molecules are hydrolyzed to tripeptides, dipeptides or amino acids prior to mixing with the metal salt to form a proteinate. In order to form a metal proteinate the proper amounts of constituents must be present at the right conditions. The mineral to be chelated must be in soluble form and the tripeptides, dipeptides or amino acids must be free from interfering protons, i.e., non-intact, in the chelation process so that chemical bonds can be formed between the proteinate ligand and the metal involved. Since chelates, by definition, are molecular structures in which a heterocyclic ring can be formed by the unshared electrons of neighboring atoms, it is essential that before a protein hydrolysate can complex with a metal ion to form co-ordinate bonds, that the protons in the chelating agent, i.e., the amino acid dipeptide or tripeptide be removed. Again, by definition, a chelating agent is considered to be an organic compound in which the atoms contain donor electrons which form more than one co-ordinate bonds with metal ions in solution. Thus it is essential that the chelation process take place in solution. Once the chelating mineral salt is completely soluble and the amino acids or peptides are sufficiently soluble, the pH must be adjusted to a point that is sufficiently basic to remove interfering protons from both the amine groups and the carboxyl groups of the ligands. While a pH of 7.5 may be sufficient a pH in the range of 8-10 is preferred. This allows heterocyclic rings to be formed by bonds between the metal and lone pairs of electrons left behind on the amine groups.

Thus, the mere mixing of intact amino acids or intact peptides with water in the presence of a metal salt will not result in a chelate or proteinate because the protons on the carboxyl and amine groups interfere with chelate formation. When combining protonated or intact peptides or amino acids with a soluble metal salt either no reaction takes place or a salt may be formed from the metal with the peptide or amino acid, which salt may be soluble or may precipitate. The present metal proteinates formed according to the invention precipitate in basic solutions and are insoluble or only partially soluble in water solutions. Moreover, metal proteinates or chelates are heterocyclic complexes and are vastly different from metal salts of peptides or amino acids, The metal proteinates are more readily assimilated making the metal more readily available to the body tissue.

In general, the stability of the metal protein ate increases as the oxidation state of the metal ion increases. Also shorter amino acid groups produce stronger proteinates; hence amino acids are preferred over peptides.

The co-ordination number, which is quite different from the valance tells how many co-ordinate covalent linkages a metal may have. Using iron as an example, the number may vary from two to eight although other values are also known. The ferrous ion, may have four waters of hydration. Since most metals have coordination number of two to eight their ions become incased within hydration shells made up of waters of hydration wherein each electronegative oxygen atom of each water molecule is attracted to the positively charged metal ion.

Every bond between the metal, in this case, iron and oxygen atoms consists of two electrons. The water molecules are said to be co-ordinated to the metal because each oxygen atom contributes both electrons that make up the co-ordinate covalent or simply covalent bonds.

A complex is formed when a substance other than water forms a co-ordinate or covalent bond. A chelate may be a complex but not all complexes are chelates.

Oxygen and nitrogen are electronegative elements that contribute electron pairs to form covalent bonds. Amino acid and peptide ligands contain both of these electronegative elements. A ligand may refer to the part of a molecule which contains these negatively charged elements and is the site where complex formation occurs. The term "ligand" is also used to designate the metal binding molecules themselves. As previously stated the term chelate or proteinate refers to a metal containing at least two ligands. When a metal proteinate has two or more ligands it may be referred to as a bi-, tri-, quadri-, quinque-, or sexadentate proteinate, etc. A metal proteinate is a complex containing two or more heterocyclic rings. The term "chelation", therefore refers to a particular kind of metal binding where the amino acid function of the molecule is clamped onto the metal at two or more sites, thus producing the heterocyclic ring. Obviously a metal cannot form a co-ordination complex with an intact amino acid or peptide.

Therefore it is important to metal chelate formation that the interfering protons be removed from the carboxyl and amino groups before chelation can take place.

To form a metal proteinate the co-ordinated water molecules will be replaced by the ligand.

Chelates differ from salts and other complexes due to their closed ring structure in which metals are tightly held. Generally five membered chelate rings are most stable. It is to be remembered that while covalent bonds are most stable and are preferred some ionic bonding may be formed in each chelate. The transition metals tend to form more stable covalent bonds whereas alkaline earth metals are more likely to contain some ionic bonds.

Stability constants may be determined by polarography wherein it is shown the chelates are of the magnitude of 103 to 1013 times more stable than the corresponding salts or complexes.

When forming a metal proteinate the pH of the solution drops upon the addition of the ligand. It is important that the protons on the ligand be removed so that they do not interfere with chelate formation by competing with the metal ion.

Using glycine, the simplest amino acid, as a model and iron as the metal ion containing four waters of hydration the reaction would be as follows.

Thus a complex is formed which may or may not be soluble in the aqueous reaction media. Upon the addition of more base such as NaOH the product becomes

This represents a true metal proteinate wherein all of the protons on the ligand have been removed and thus heterocyclic rings have been formed. Note that each ring has five members which are found to be most stable. From the above it is imperative that the ligand protons be removed and full chelation be carried out under basic reaction conditions.

Metal proteinates are relatively insoluble in basic solutions but depending upon the concentration, metal proteinates at low concentrations are soluble or partially soluble in slightly acidic to alkaline solutions.

When administering metal proteinates orally to warm blooded animals a portion of the product may be destroyed by the acidic media of the stomach thus depriving the animal from the full benefit of the dosage administered. It has been shown, however, that a major proportion of the metal proteinates are passed intact into the intestine for absorption.

The metal proteinates can be stabilized and thus pass more readily through the stomach when buffered to a constant pH from 7 to 11. The buffer system may change according to the metal proteinate being administered, and one or more metal proteinates may be administered at one time.

The choice of buffer system will depend upon the pH desired. Amino acids alone will react with bases such as sodium hydroxide to form buffered systems.

Typical buffer solutions include phosphate, carbonate and bicarbonate anions or mixtures thereof. Either alkali or alkaline earth metals may be used as cations in the buffer systems. Examples of typical buffering systems in the pH range of 7 to 11 are as follows: pH 7 9.1 g. KH2PO4+19.7 g. Na2HPO4 per liter.

7 50 ml. M/5 KH2PO4+22.4 ml. M/5 NaOH diluted to 200 ml.

8 50 ml. M/5 KH2PO4+46.1 ml. M/5 NaOH diluted to 200 ml.

10 6.5 g. NaHCO3+13.2 Na2CO3 per liter.

11 11.4 g. Na2HPO4+19.7 g. Na3PO4 per liter.

The present compositions may employ any mixture of organic or inorganic substituents which will buffer or maintain a system at a pH range of 7 to 11. There are numerous other buffering systems readily available to one with ordinary skill in the art and mere enumeration of them would be redundant. What is important to the invention is that a buffering system be selected which will not only stabilize a metal proteinate but will also be non-toxic and assist in the assimilation of the metal proteinate into the body.

The term warm blooded animal is intended to encompass all species of the animal kingdom including man.

The dosage to be administered will depend upon the type of formulation, the amimal species, weight, age, sex and the metal proteinate or mixture of metal proteinates being administered. It may first be desirable to determine the metal deficiencies in an animal by assaying hair, nails, blood, urine, skin or saliva from the animal and comparing the results with a standard representing a normal healthy animal of the same species. A corrective formulation can then be made up. On the other hand it may be desirable to administer the RDA of each metal in one or more dosages. For example the RDA for an average adult is, Iron 18 mg.; Zinc 15 mg.; Copper 2 mg.; Magnesium 400 mg. and Calcium 1000 mg. There have been no RDA's set for other minerals which have been considered essential to the proper functioning of the body.

The metal proteinates can be given in various ways as long as a biologically effective amount is administered. When administered orally the metal proteinates can be admixed with a suitable carrier and given in the form of tablets, pills, capsules, emulsions, syrups or admixed with foodstuffs. When given to domestic form animals or pets, the metal proteinate will preferably be admixed with, sprinkled on or poured over the animal's food. Compositions of metal proteinates may also be given by stomach tube or by a valve.

When given to a human the metal proteinates may be administered as a tablet, syrup or capsule or may be admixed with or placed on the surface of food such as meats, stews, bakery products, candies, deep fried foods or placed in seasonings or spices.

To further demonsrate the stability of metal proteinates and their ability to raise the level of metals in biological tissues, and to illustrate various compositions and methods of administration the following examples are given.

EXAMPLE I A mixture of 200 Ibs. of casein and 1000 Ibs. of water was mixed in a jacketed tank and stirred. Six poinds of sodium hydroxide was added to neutralize and bring the casein into solution. A mixture of three pounds each of the enzymes papain, bacterial protease and fungal protease was added along with a preservative such as sodium benzoate. The mixture was covered and stirred for a period of six days to produce a hydrolysate containing over 85 /" tripeptides, dipeptides and amino acids. The enzymatic action was stopped by bringing the solution to a boil for about 15 to 20 minutes and filtered while hot through muslin. The filtered solution was then ready for use in preparing metal proteinates according to the following examples. Other protein sources such as gelatin, collagen, yeast, fish meal and soya could be used in the place of casein. It will be noted that in most cases the metal content of the proteinate formed will vary from about 5 to 15 percent by weight with 10 percent being the average.

EXAMPLE II To a filtrate prepared as in Example I was added 33 pounds of zinc chloride.

To this solution was added sufficient sodium hydroxide to raise the pH to about 8.5 which produced a precipitate containing about 14 percent zinc as a zinc proteinate.

The ligand to metal mole ratio was found to be two to one.

EXAMPLE III Example II was repeated using 75 pounds of ferrous sulfate (FeSO4 .7 H2O).

The washed and dried precipitate produced about 175 pounds of iron proteinate containing nine percent by weight iron.

EXAMPLE IV Again Example II was followed using 41 pounds of cupric chloride (CuC12 .2 H2O) plus 1000 pounds of methyl alcohol. The collected precipitate contained about 180 pounds of a copper proteinate containing eleven percent by weight copper.

EXAMPLE V The procedure of Example II was again repeated using 56 pounds of manganese chloride (MnCl2 .4 H2O). The precipitated manganese proteinate contained about eight percent manganese and weighed about 170 pounds.

EXAMPLE VI An acid hydrolyzed soy protein hydrolysed to the tripeptide, dipeptide and amino acid stage was prepared by mixing 16 pounds of water with 5.7 pounds of concentrated hydrochloric acid. Ten pounds of isolated soya was added with mixing and the mixture was heated to 1300C for 4 hours to hydrolyze the protein.

The hydrolysate was neutralized with 4 pounds of zinc carbonate and the pH was adjusted to 8.5 by the addition of sodium hydroxide. The precipitated zinc proteinate was washed and dried to obtain a product containing about 15 percent by weight zinc.

In each of the above examples the ligand to metal mole ratio was at least two to one.

Other acids and bases could be used in the hydrolysis process such as phosphoric acid, sulfuric acid, and sodium hydroxide.

EXAMPLE VII The stability of metal proteinates, exemplified by zinc methionate is demonstrated as follows.

Traces of Zns5CI2 were mixed with non radioactive zinc chloride and chelated with methionine as an amino acid. To demonstrate structure and how tightly the methionine was bound to the zinc, a polarographic study was made. A solution was prepared containing .0001 moles of zinc per 100 mls of solution of ZnCl2, and there was added thereto sufficient 0.2 M methionine to produce a solution having a molar ratio of amino acid to zinc as follows: Mls of 0.2 M Moles Ratio Solution Methionine Methionine Zinc 1 O ml 0 2 2.5 ml 0.5 3 5.0 ml 1.0 4 10.0 ml 2.0 5 20.0 ml 4.0 6 40.0 ml 8.0 7 80.0 ml 16.0 To each of the above solutions was added 10 mls of 1 M potassium nitrate (KNO3) as an electrolyte and 10 mls of a 0.lVn gelatin solution. Each solution was corrected to a pH of 7 by the addition of a few drops of concentrated (6 N) sodium hydroxide (NaOH) solution.

Using a Metrohm E 261 polarograph with a silver/silver chloride (Ag/AgCl) reference electrode, the following E1,2.s were recorded: Solution No. E1,2 1 -1.008 2 -1.033 3 -1.057 4 -1.079 5 -1.090 6 -1.110 7 -1.129 A plot of the log of the proteinate ligand concentration against the E1,2 gives a sloped line which is indicative of the number of ligands in the complex. It was found that the Zn++ ion complexes with two molecules of methionine.

While not wishing to be bound by any specific theory, it is believed that at higher ligand concentrations and at a higher pH (more basic) the complex is probably a bicyclic complex.

By knowing the number of ligands, the stability constant at different concentrations and pH's can be determined. It has been found that the logarithm of the stability constant equals:

2 .059 log K= 059 E112- p log [ligand] .059 2 where p=the number of ligands and [ligand] refers to the concentration of the ligand.

Solution Number 7 (16 moles of methionine per mole of zinc) was found to have a stability constant equal to 4.94x 107 at pH 7. The same solution was adjusted to a pH of 9 and the stability constant was found to be 4.41 x 10'2. In other words, by changing the pH of a zinc methionate solution of the same concentration from 7 to 9 an increase in stability of 105 or 100,000 was obtained. Similar results can be demonstrated with copper, iron, chromium, calcium, manganese, magnesium, vanadium and other essential metals.

EXAMPLE VIII In this series of experiments, day-old chicks were divided into groups and each group, control and treated, was fed the same commercial chick-starter ration. For example, one commercial chick-starter ration has the following composition: soy bean meal, meat meal, ground corn, ground milo,-salt, fat, dicalcium carbonate, limestone, and an inorganic trace mineral mix. This chick-starter ration had 22 /,, protein, and a fat content giving a metabolizable caloric content of 1250 calories per pound. The ration also contained vitamins in addition to the standard inorganic mineral supplement. Each group of chicks referred to as "treated" received a different predet

Group 4: Given a (0.OIX) capsule (see Table II) daily by mouth.

Group 5: Given 0.0IX level of metal proteinate blend in the pre-starter ration which was prepared by mixing 10 grams of (IX) metal proteinate blend with 990 grams of pre-starter ration.

The metals dosage per capsule is also given in Table II. Dilution of the starting amount (IX) was made in factors of ten (0.IX) and (0.0IX) with lactose diluent.

TABLE II Metal Dosage Per Capsule (IX) (0.IX) (0.oil) Metal mg/capsule mg/capsule mg/capsule Co 0.0296 0.00296 0.000296 Cu 0.0459 0.00459 0.000459 Mn 0.115 0.0115 0.00115 Fe 0.230 0.0230 0.00230 Zn 0.492 0.0492 0.00492 Ca 4.592 0.459 0.0459 Mg 4.592 0.459 0.0459 The average daily weights for each group was then determined and is reported in Table III.

TABLE III Average Daily Weights of Turkey Poults (All Weights in Grams) 1st 2nd 3rd 4th 5th Day Day Day Day Day Group 1 (Control) 48.7 51.4 60.0 64.3 74.6 Group 2 (IX) Capsule 50.7 50.5 65.8 73.4 80.9 Group 3 (0.IX) Capsule 50.6 53.4 64.2 65.3 77.9 Group 4 (0.OIX) Capsule 50.2 50.4 65.6 75.5 85.0 Group 5 (0.OIX) in Feed 51.8 53.0 66.6 68.6 84.6 Of particular interest in the results set forth above is that, in general, the treated turkey poults posted significant weight increases over the control group for each dilution of the metal proteinate, whether the metal proteinate was forcefed or amended to the diet.

As a further note of significant interest in the foregoing evaluation using turkey poults, deaths of some of the birds was experienced. Death losses which were diagnosed as due to para-colon appeared in the control group and at the lower dosage levels of metal proteinate (Groups 1, 3, 4 and 5). The excellent condition of poults in Group 2 suggests a possible beneficial effect of higher levels of the metal proteinate in increasing resistance to para-colon.

Additional benefits to be derived from the discovery that metal deficiencies can first be diagnosed and then corrected through this invention are set forth below in the following examples.

EXAMPLE X Ten thousand laying hens were chosen and separated into two groups of five thousand each. The same commercial layer ration was fed both groups. Feathers from representative samples of both groups were assayed to determined the metals profile of the hens. The metals profile thus obtained was compared to a standard profile obtained on the basis of data compiled from assay of feathers from young, healthy, laying hens. Deficiencies were observed and on the basis of this comparison, the commercial feed composition was amended with metal proteinates blended according to Table IV. Controls were fed corresponding amounts of inorganic metals.

TABLE IV Metal Composition or Feed Blend Calcium 4.5/ Magnesium 4.6/ Zinc .4/ Iron .2/ Manganese .1/ Copper .04/ Cobalt .02% The foregoing metal feed blend was thoroughly mixed with the commercial layer ration on the basis of two pounds of metal feed blend per ton of commercial layer ration.

Group 1 received the metals of Table IV as proteinates of each metal. Group 2 received the same amount and ratio of metals blended per ton commercial feed ration as fed Group 1. However, the metals were in the form of inorganic metals. In a sixty-day period, the hens of Group 1 which were treated with metal proteinate of the mentioned formulation layed 18,210 more eggs than hens treated with the inorganic metals. Moreover, a very favorable effecf on the quality of the eggs was found to result. Eggs from Group 1 require an average of 1.7 pounds more pressure to break the egg shell than eggs from Group 2. Also, the lining of the eggs of Group I showed greater tensile strength. An alaysis of egg yolk determined that there was 11.14/ more zinc, 10.50/ more iron and 6.0/ more copper in eggs laid by Group 1.

In the increase in the number of eggs produced by Group 1 resulted not only from a higher lay rate but also from increased capacity to lay over a longer time span. Table V sets forth the results measured as the percentage of hens laying an average of one egg per day (lay rate) at the peak lay period for the group and six months after the peak. Hens in both groups started laying at 20 weeks of age.

TABLE V Group 1 Group 2 (Treated) (Control) Peak Lay Rate 85/ 75/ 6 Months After Peak 80/ 64/ The hens were forced to molt after the sixty-day period. Just prior to molt, assays of the feathers showed that Group 1 averaged 1017 /n higher metal levels than the control Group 2.

EXAMPLE XI Twenty-five hundred laying hens, which had been in peak lay three months, were selected and twenty-five randomly-selected chicks reproduced by these laying hens were chosen as controls. The average hemoglobin level in gm / of the chicks was 8.7 gm /. The hens were then placed on a diet supplemented with the metal proteinate blend of Example IX. Forty-three days later eggs from the treated hens were set and twenty-five randomly-selected (treated) chicks from those eggs were assayed for hemoglobin. The average hemoglobin of the second group of chicks was 9.4 gms / as compared to 8.7 gms / of the control chicks. Significantly, the death loss in the first seven days of life between the control chicks and the treated chicks decreased from 2.0/ to 0.8/.

Accordingly, it was found that supplementing the diet of the laying hens with metal proteinates resulted in improved hemoglobin levels in their offspring and decreased death loss of chicks.

EXAMPLE XII Five hundred laying hens diagnosed as having avian leucosis were given metal proteinates along with normal feed ingredients. The formulation of the metal proteinates was the same as set forth in Table IV with calcium, magnesium and zinc the predominant ingredients. The yellow appearance of the combs and the wattles which normally attend this disease disappeared within thirty days and the comb and wattle returned to the normal red color. Also, the birds took on a healthy appearance and the death loss became negligible. Egg production and the quality of the egg shell returned to the normal range within this thirty-day period while egg breakage in the nests was decreased 97/.

EXAMPLE XIII Five races of fingerling cut throat trout, each race having approximately fifty thousand fish, were each given a feed ration with an addition of one-half per cent per ton of a metal proteinate formulation (see Table IV). The five races of fish were compared with a race of control fish given the same feed ration without the metal proteinate addition. Samples of the fish in each race were weighed every two weeks for approximately one year. It was discovered that the feed conversion, i.e., the amount of food required to produce one pound of meat, was much higher in the fish fed with rations having the metal protinate addition. The treated fish consumed an average of 1.2 pounds of feed per pound of weight gained while the control trout consumes an average of 4.2 pounds of feed per pound of weight gained.

EXAMPLE XIV Anemia in baby pigs due to iron deficiency has historically been a problem when sows and their offspring are confined without access to the soil or pasture.

The baby pigs are particularly susceptible to this type of anemia because of their high rate of growth, low body reserves of iron at birth, and low iron levels in sow's milk. A normal growth rate for baby pigs means an increase in body weight of four to five times their birth weight at the end of only three weeks. A growth rate of this magnitude requires the retention of about 7 mgs. of iron per day. However, sow's milk supplies only about I mg. per day and baby pigs consume little feed other than sow milk for the first three of four weeks. Accordingly, the need for an iron dietary supplement is readily apparent.

Inorganic iron supplements fed to the sow both before and after farrowing has proven ineffective in either raising the iron content of the sow's milk significantly or increasing the iron levels of the baby pigs at birth. Treating the baby pigs is routinely accomplished either by (a) oral administration of 400 to 500 mgs.

inorganic iron as tablets or solutions within four days of birth and again at two weeks, or (b) at least two injections of 100 to 200 mgs. iron-complex solution during the early growth period. The foregoing has proven inadequate since even frequent treatment by these steps is insufficient to allow the piglets to achieve maximum growth. This shortcoming is further compounded by the handling requirement of large numbers of animals which renders the procedure impractical. Accordingly, it is most desirable to assay tissue (e.g. blood) from the animal and amend the diet of the sow with appropriate metals and in sufficient amounts to enable the sow to pass the metals to the piglets through the sow's milk.

After suitable analysis, the following formulation of Table VI was prepared as a dietary supplement for sows. The metals were formulated as proteinates.

TABLE VI Assay of Metal Proteinate for Swine Percent Metal Composition Mg 6.80/ Fe 1.86 Zn 1.26 Cu 0.05 Co 0.0024 The foregoing formulation of Table VI was fed to one group of sows at a rate of five pounds per ton of feed and the same amount of metals as inorganic metals was fed to a second group of sows. This second group of sows served as a control. A random sample of both the treated and control feed rations analyzed for metal content showed 14 mg. iron/100 grams.

Blood hemoglobin levels were determined initially (thirty days prior to anticipated farrowing) and continued until the piglets were weaned at about sixty days of age. Piglet weights and blood hemoglobin levels were determined at birth and upon weaning. The results of hemoglobin determinations and piglet weights are set forth in Tables VII and VIII below: TABLE VII Hemoglobin (Hb) Levels (gm/100 ml) Group Control Treated Sows Hb Range Average Hb Range Average Iri'itially 12-IS 13.5 12-14 13.5 At farrowing 1214 13.3 13-15 14.3 Litters At birth 7.5-9.8 9.0 9.6-12.0 11.0 At weaning 10.7-12.0 11.7* 11.9-12.8 12.2 * some piglets required iron injections TABLE VIII Litter Weights (Average in Pounds) Control Treated Birth 3.60 Ibs. 3.53 Ibs.

Weaning 37.25 Ibs. 39.25 Ibs.

Gain 33.00 Ibs. 35.65 Ibs.

It should be particularly emphasized that in the foregoing example some of the control piglets required iron-complex injections to prevent loss of the piglets and, therefore, the hemoglobin level for the control piglets may be artifically high. Even with injections given to the control piglets, the piglets which nursed on treated sows had higher hemoglobin levels and heavier weights at weaning.

EXAMPLE XV A group of 58 sows with similar breading history was randomly divided into three groups. Group I sows received normal gestation and lactation diets and no form of iron supplementation was given to their offspring. Group II shows also received normal gestation and lactation diets, but their piglets were given 100 mg.

of iron dextran by intramuscular injection at one and fifteen days of age. Group III sows received normal gestation and lactation diets to which 500 PPM of iron as an iron proteinate containing about 10/ by weight iron was added. No other form of iron supplement was given to the piglets farrowed by Group III sows. The results were as follows in Table IX.

TABLE IX Group I Group II Group III (no Iron) (Iron Dextran) (Iron Proteinate) No. Sows 13 27 18 No. Piglets Farrowed 144 285 168 Ave. Hb of Sows at Farrowing (gm/100 mls) 12.03 13.5 14.0 Ave. Hb of piglets at Farrowing (gm/100 mls) 11.41 11.12 11.35 Ave. Piglet birth weight (Ibs.) 2.86 2.82 2.99 No. of Piglets Weaned 115 233 157 Ave. Hb at Weaning (gm/100 mls) 7.32 11.69 10.83 Ave. Weaning Weight (Ibs.) (37 days) 14.96 16.53 17.43 Percent Mortality 20.1 18.3 6.5 Total Weaning wt./ Piglet Farrowed (Ibs.) 11.95 13.51 16.28 The above table shows that piglets farrowed by Group I sows showed lower hemolobin (Hb) and weight at weaning and higher mortality than Group II and III.

A careful observation of Groups II and III show impressive benefits of iron proteinate supplementation to the sow. Both Groups II and III show hemoglobin levels well above the anemia level of 9.0 at birth and at weaning. The average birth weight of Group III piglets was 0.17 Ibs. heavier than Group II piglets. Replicated studies consistently show a difference between 0.15 and 0.25 Ibs. heavier birth rate when supplementing the sows diet with iron proteinates. Group III piglets also averaged 0.9 Ibs. or 5.2/ greater weaning weight than Group II piglets. The difference in mortality was the most significant benefit derived from iron proteinate administration. In this study 2.82 times as many pigs on the average died in the group (Group II) receiving iron dextran injections than in Group III piglets receiving their iron supplementation through the sows diet. The final entry shown in Table IX is a figure which combines the effects of mortality and weaning weights. This entry shows Group III having a 17% improvement over Group II or 2.77 Ibs. greater weaning weight per piglet farrowed.

From the above it is clear that the iron proteinate provided higher birthweights, lower mortality and higher weaning weights than piglets that received iron dextran by injection.

From the foregoing, it is clear that surprisingly beneficial effects result from making essential metals available to animals in a biologically acceptable form. With these essential metals readily available to the animals, the animal is no longer required to synthesize its own metal proteinate from inorganic metals and thus individual differences in biological capability of animals are no longer responsible for an inadequate nutritional level of metals.

Furthermore, a determination of the metal level in the tissue of a healthy animal to establish a standard and comparison of the metal level of a selected animal with that standard enables one to suitably prescribe a corrective dietary supplement.

EXAMPLE XVI It has been taught that metal proteinates are formed in basic solutions at a pH above about 7.5 and preferably between 8 and 10.

The following compositions were made to demonstrate the viability of these teachings.

Ten microliters of 0.073 M ZnCl2 containing 912 microcuries of radioactive Zn65 were mixed as follows: A. Ten microliters of 0.076 M L-leucine (equamolar ratios of amino acid and zinc) was combined with the zinc at a pH of about 3.5 and adjusted to pH 7 with 20 microliters of sodium hydroxide.

B. Twenty microliters of 0.076 M L-leucine (2:1 ratio of amino acid to metal) was combined with the zinc solution at a pH of about 3. Twenty microliters of water was added.

C. Twenty microliters of 0.076 M L-leucine and twenty microliters of 0.13 M Na2CO3 were combined with the zinc solution to form a metal proteinate at a pH of 9.

Each of the above formulations represent a unit dosage.

Six white male rats weighing 160 g.+8 g. were matched to provide equal weights for each set of two rats. The three solutions of each formulation were carefully mixed to prepare a dose. Each rat was mildly sedated with ether and was dosed orally using an Eppendorf pipet. Each rat swallowed the mixture readily except one being dosed with mixture C, who swallowed most of the mixture after considerable coaxing. The rats had been fasted for 16 hours prior to dosing and were returned to normal feed and water immediately after dosing.

After 46 hours the rats were sacrificed and dissected to remove blood, liver, left kidney, heart, skeletal muscle, and brain from each animal. One animal given mixture B had a left kidney only 1/20 normal size. No Znfl5 was detected in this rat's muscle or brain and therefore the results from that rat were not utilized. The samples or tissue were dried, weighed and then counted using a nuclear Chicago Model 8731 rate meter and a Nuclear Chicago Model 8770 digital scaler. The values given in Table IX are the corrected counts per minute per mg. and are the average of two animals except for Mixture B.

TABLE X A B C Blood 0.90 1.31 1.64 Liver 5.15 6.20 8.65 Kidney 5.45 6.46 8.55 Heart 6.42 5.23 6.32 Muscle 2.41 3.10 3.88 Brain 1.22 3.86 2.41 Total cc/min/mg. 21.55 26.16 31.45 By dividing C by A and B it can be seen that the zinc proteinate (C) provided 1.46 times greater metal absorption than mixture A and 1.20 times greater absorption than mixture B.

EXAMPLE XVII The procedure of Example XV was followed to using radioactive iron (Fe59).

Each unit dosage was as follows: A. Ten microliters of 0.050 M Feed4 .7 H2O-containing the microcuries of radioactive Fe59. Ten microliters of 0.050 M L-glumatic acid Forty microliters of NaOH to bring the solution to a pH of 6.

B. Ten microliters of 0.050 M Feed4 .7 H2O containing ten microcuries of radioactive Fe59 twenty microliters of 0.076 M L-leucine forty microliters of water to obtain a pH of 3.

C. Ten microliters of 0.050 M Feed4 .7 H2O containing ten microcuries of radioactive Fe59 twenty microliters of 0.076 M L-leucine forty microliters of 0.13 M Na2CO3 to form an iron proteinate at a pH of 9.

Six white male rats weighing 133 g.jS g. were matched and dosed as in Example XV and the tissues were removed, dried and counted with the results being reported in Table XI.

TABLE XI A B C Blood 36.1 34.0 83.0 Liver 11.7 16.1 38.4 Kidney 4.5 5.5 8.5 Heart 2.6 4.7 9.7 Muscle .3 1.7 2.7 Brain 0 2.1 1.5 Total cc/min/mg. 55.1 64.1 143.4 Again by dividing C by A and B it can be seen that the iron proteinate (C) provided 2.60 times greater absorption of iron than mixture A and 2.24 times greater iron absorption than mixture B.

In both Examples XV and XVI mixtures A and B were not metal proteinates although in mixture B, in each case, the amino acid to metal ratio was at least 2:1.

EXAMPLE XVIII The following study was done to illustrate the way animals absorb buffered metal proteinates. White laboratory rats were used as experimental animals, and each rat received the same amount of tagged zinc chloride by dosing with a pipette directly into the rat's stomach. The molar ratio of zinc to methionine was one to two for Rat II and III, and the pH was adjusted according to the following table: TABLE XII Rat I Rat II Rat III 24 microliters Zn65CI2 24 microliters Zn99Cl2 24 microliters Zn65Cl2 75 microliters H2O 25 microliters H2O con- 25 microliters H2O taining NaHCO3/Na2CO3 containing NaOH to to pH 10 pH 7 50 microliters methionine 50 microliters methionine - solution 2:1 molar ratio - solution 2:1 molar with Zn++ ratio with Zn++ The rats were placed in metabolic cages on a normal diet and were observed for one week during which time the feces were collected. At the end of the week, the rats were sacrificed, and the total excreta measured by scintillation count for radioactivity as compared to a blank. The following amounts of Zn95 were excreted by each of the rats as measured by the collected feces for the week: / of Total Dose Excreted Rat I 52% Rat II 12/ Rat III 36/ More than half of the Zn65 in the control animal was lost. The Zones methionate retention in Rat II administered at pH 10 was significantly better than the ZnsS methionate retention in Rat III administered at pH 7. However, both showed marked improvement in Zn retention over Rat I.

EXAMPLE XIX Example XVII was essentially repeated using Fe59SO4 as the control. The solution was orally administered by pipette into the stomach. Each rat received 36.7 micrograms of Fe59 in 20 microliters of solution. Rat II was administered a methionine solution and Rat III a glycine solution, both buffered to a pH of 10 in a molar ratio of one to two metal to amino acid. At the end of a week, the rats were sacrificed and parts of various organs analyzed for Fe59 by scintillation count.

The following results were obtained: TABLE XIII Corrected Counts per Minute per Gram Rat I RatIl Rat III Tissue FeSO4 FeMet FeGly Heart 63. 151. 83.

Liver 136. 243. 83.

Gastroc 2. 54. 83.

Masseter 14. 138. 65.

Brain 31. 130. 142.

Kidney 2. 327. 150.

Testes 20. 109. 75.

Serum 700. 1,797. 840.

Cells 742 2,076. 773.

Blood 1,335. 4,215. 1,602.

Feces 302,400. 214,000. 205,800.

Urine 490. 370. 690.

Rat I Rat II Rat III Feces 45.8/ Lost 32.4/ Lost 31.2/ Lost The results reported above are very dramatic. The amounts of Fe59 retained by Rats II and III administered the buffered Fe59 proteinate were significantly higher than in Rat I as demonstrated by the feces analysis. The amounts of metal retained in the tissues were also significantly higher in almost every instance. However, detailed results were not computable because the complete organ was not removed for analysis.

Buffering systems which were used in the above examples include amino acid NaOH solutions and a solution of 6.5 grams of sodium bicarbonate (NaHCO3) and 13.2 grams of sodium carbonate (Na2CO3) per liter of solution which will produce a buffered solution of about pH 10.

EXAMPLE XX To further substantiate the effects of buffering metal proteinates, the following tests were conducted on rats which had been fasted over night. Each rat was given the following dosage of radioactive calcium by injection into the duodenum: Rat I 250 microliters of Cacti2 solution (1 mg. Ca) in distilled H2O.

40 microliters of distilled H2O (40 mcC Ca45)* as Ca45Cl2.

*mcC=microcuries.

Rat I1 250 microliters of CaCI2 solution ( I mg. Ca) in distilled H2O buffered to pH 7 with NaOH and the amino acids and containing in molar ratio with calcium 2 moles of aspartic acid, 2 moles of glycine and 1 mole of methionine.

40 microliters of distilled H2O (40 mcC Ca45) as Ca45CI2.

Rat III Same as Rat II except buffered to pH 10 with NaHCO3/Na2CO3.

The rats were fed a normal diet for one week, and the feces were collected. At the end of one week the rats were sacrificed and the total feces and portions of the tissues were analyzed by scintillation count. The results obtained are as follows: TABLE XIV Corrected Counts per Minute per Gram Tissues Rat I Rat II Rat III Frontal Bone 3682 5878 5772 Massater 602 844 904 Gastroc (muscle) 614 620 1206 Heart 642 598 932 Liver 664 546 742 R. Cerebrum 698 726 804 Kidney ' 686 656 730 Lung 676 672 648 Serum) 8.4 39.6 31.0 100 microliters Blood Cells) 18.6 0 13.2 Total Blood 27.0 39.6 44.2 It is evident from the tissue counts that much more of the calcium proteinate was assimilated into the tissues at the buffered pH of 10 than at pH 7. However, it is also evident that more of the calcium proteinate was absorbed at the buffered pH 7 than was the calcium salt control.

Insofar as the feces is concerned, it was found that about four times as much calcium was excreted in the simple organic salt control (Rat I) than in the buffered (pH 10) calcium proteinate. Moreover, the pH 10 proteinate was approximately twice as effective in retaining calcium than was buffered (pH 7) proteinate. It would thus appear that buffering undoubtedly assists in both promoting stability of the metal proteinate solution and in improving its assimilation into a host of various tissues.

EXAMPLE XXI The above examples tend to show that a buffer system at about pH 10 will improve certain metal assimilation into living tissues. This pH however is not optimum for all metals. Some metals actually are better absorbed at a lower buffered range. The object is to find and maintain the optimum pH range for the metal to be administered. This may be empirically established for each metal protein ate.

Manganese, for example, is absorbed better as a proteinate at a pH of about 7 for more basic systems it tends to form Mn (OH)2.

Manganese, and calcium also do not function as well with carbonate buffered solutions in that they tend to form insoluble carbonates.

The absorptive capacities of manganese proteinates at a buffered pH of 7 are demonstrated below. Two solutions utilizing Mn54 were made up as follows: Solution I 250 microliters distilled H2O containing 100 mg. of Mn as MnCl2.

50 microliters Mn54 solution (14.3 mcC) as Mn54Cl2.

Solution II 250 microliters distilled H2O containing 100 mg. of Mn as MnCl2.

50 microliters Mn54 solution (14.3 mcC) as Mn54CI2.

Based on a molar ratio of total manganese, the solution contained per mole of manganese, 2 moles each of the amino acids - methionine, glycine;aspartic acid and glutamic acid. The solution was buffered to a pH 7 with NaOH interacting with the amino acids.

The solutions prepared were injected into the duodenum of laboratory rats (labeled Rat I and Rat II according to solution given) which were fed a normal diet for one week and then sacrificed. The tissues were then measured by scintillation count as an indication of manganese proteinate uptake. The results are as follows: TABLE XV Corrected Counts per Minute per Gram cc/min/gm dry wt.

I II Heart 370 1190 Kidney 470 600 Brain 620 1170 Gastroc 800 660 Masseter 270 310 Liver 760 1070 Lung 720 330 Frontal Bone 350 780 Duodenum 170 480 As will be noted from the above table, almost all counts were higher in Rat II administered the manganese proteinate than in control Rat I. Counts in urine and feces from these animals were not obtained.

EXAMPLE XXII The above examples illustrate the assimilation of buffered metal chelate complexes with isolated amino acids or limited combinations of acids. This example demonstrates that hydrolyzed protein (in the form of di- and tripeptides) may be used as effectively. This example further demonstrates the placental transfer of stabilized metal proteinates from the mother to the unborn fetus. Mink were chosen for these tests and iron was chosen for the metal proteinate. This was done because many authorities in mink production believe that mink have difficulty in placental transfer of iron from mother to young.

Two pregnant mink individually housed were fasted for twenty to twenty-four hours and were then given 24.17 milligrams of iron containing 5 mcC of Fe59 radidactive isotope. Mink No. I was given the iron in the form of Fe59SO4 which had been chelated into hydrolyzed protein in the form of di- and tripeptides and buffered with a NaHCO3/Na2CO3 solution to a pH of 10. Mink No. 2 was given the same amount of iron a

TABLE XVI General Data Mink No. 1 Mink No. 2 Total / Fe++ Retained 70.4 42.7 Total / Fe++ Excreted in feces 24.4 29.6 Total / Fe++ Excreted in urine 5.17 27.7 / Fe++ Excreted in Feces 4 days after dosing 21.5 23.8 / Fe++ Passed on to young (kits) 0.03 (7.3 micrograms) 0 Hemoglobin Mother-gm / 20.5 20.0 Hematocrit / 45 44 Average Hemoglobin of young (kits) gm/ 19.5 19 Average Hematocrit of young (kits) 53 50 Whole Body Counts Without Organs Mother (corrected counts/minute) 112.4 68.1 Average Body Counts Per Kit (Corrected Counts/minute) 42.3 1 TABLE XVII Corrected Counts per Minute per Gram Tissue Mink No. 1 Mink No. 2 Masseter 7.81 12.00 Pectoralis Major 1.22 5.02 Spleen 15.3 10.60 Brain 9.7 7.57 Lung 6.4 4.05 Heart 2.7 5.12 Liver 4.98 4.73 Neck Fur and Skin 6.24 3.82 Scalp 5.74 6.33 From the above data several conclusions can be drawn. It is at once evident that the amount of Fe retained in Mink No. 1, dosed with the buffered iron proteinate was 65/ greater than the amount retained in Mink No. 2 dosed with Fe2SO4. Stating it another way about 70/ of the iron in the buffered iron proteinate was metabolized whereas only 42.7/ was retained in the mink treated with Fe2SO4.

Comparing the amounts of iron excreted after 4 days with the final analysis, it is evident that in Mink No. 2, 33.5/ of the iron initially dosed was absorbed but not metabolized, and was eventually eliminated between the fourth and fifteenth day after dosing. In Mink No. 1 only about 8% of the absorbed iron proteinate was later eliminated and not metabilized. The data show that a measurable amount of Fe as iron proteinate was carried to the kits from Mink No. I by placental transfer (42.3 cc/min) whereas the Fe59 in the kits from Mink No. 2 was barely evident (1 cc/min).

The hemoglobin and hematocrit measurements were higher from the iron proteinate dosed mink than from the control. The iron proteinate is utilized in the blood, skin and organs more readily as shown by tissue counts. The spleen, which is 90% blood, contains about 50% more iron from the buffered iron proteinate than from the Fe2SO4 control. This is important as it demonstrates that the iron proteinate is better for building hemoglobin than the corresponding Fe2SO4.

Finally, the data show that hydrolyzed protein in the form of tripeptides and dipeptides are effective as ligands for complexing with buffered metals to form metal proteinates for transport of metal into the blood stream from the intestinal tract as are individual amino acids.

The following examples illustrate the incorporation of metal proteinates in having at least two tripeptide, dipeptide or amino acid ligands into or onto foodstuffs. The metal proteinates may be utilized in a communited form.

When used in flours or bakery products the metal content of the product available as a proteinate may vary from about .00001 to .001/ by weight.

EXAMPLE XXIII A flour containing 50 mg. of iron as iron proteinate per pound of flour was placed in a Jacksonville Flour Stability Cabinet. One week in this cabinet is equal to one month under ambient conditions. At the end of 18 weeks no rust spots developed and the metal proteinate and flour maintained complete stability.

EXAMPLE XXIV The bio-availability and stability of iron chelated into tripeptides, dipeptides and amino acids was compared against iron sulfate which is considered to be the standard in the industry and was proven to be more readily available and more stable than iron sulfate in each experiment.

EXAMPLE XXV In order to prove the applicability of iron proteinates two loaves of bread were prepared and sliced. One loaf had 4 mg. of iron as a proteinate in each slice and the other had 8 mg. of iron as a proteinate in each slice. Each loaf was calculated to contain 1.5 pounds and yield 24 slices representing 2 slices per serving. The RDA in iron is 18 mgs. per day.

The bread was prepared as follows: Formula 1 package of active dry yeast 1/2 cup of water 2 cups of scalded milk 2 tablespoons of sugar 2 teaspoons of salt 1 tablespoon of shortening 6 cups of sifted white flour The mixture was divided into equal parts and to one part was mixed 96 mgs. of iron as an iron proteinate. The other mixture contained 192 mgs. of iron as an iron proteinate.

The recipe was combined and processed in a normal manner and allowed to rise. The dough was baked at 4000 F. for 35 minutes. After baking and cooking the bread was analyzed for rust spots. None were found and the bread was then stored.

After storage the bread was superior to bread containing no iron fortification at all.

Other metal chelates could also be used in the place of iron such as magnesium, manganese, copper, zinc, cobalt, calcium or any other essential bivalent metal.

This fortification does not apply to bread alone. For example the metal chelates could be added to enriched flour, enriched self rising flour, enriched brominated flour, prepared or ready to cook breakfast cereals, poultry stuffing, rice, soya, cornmeal, corn grits, enriched bread, rolls, buns, cookies, cakes and pastries.

The metal proteinates may be incorporated into cooking oils and be absorbed or absorbed from the cooking oil into or onto foods cooked in said oils. Typical of such foods are potato chips, corn chips, french fries, donuts and other deep fried pastries and batter covered meats such as corn dogs, deep fried prawns and chicken. The metal proteinates may be used in amounts generally ranging from .2 to 2.0 grams of metal per gallon of cooking oil. At these concentrations the metal proteinates have been found to inhibit rancidity in the cooking oil. The rate of absorption or absorption of metal proteinates into or onto the foods is thought to be approximately proportionate to the amount proteinates in the amount of oil absorbed. Since the proteinates are substantially insoluble in oil the oil must constantly be stirred or agitated.

Both a vegetable and animal oils may be used. Typical of such oils are corn, palm, coconut, peanut, and safflower oils and rendered animal fats both hydrogenated and non-hydrogenated.

The following examples are illustrative.

EXAMPLE XXVI Into a vat equipped with a stirrer containing a mixture of hydrogenated palm and coconut oils maintained at 3750 F. is added a mixture of iron, zinc, and copper proteinates containing about 1.5 grams of zinc, 1.8 grams of iron, and .2 grams of copper per gallon of oil. Potatoes sliced on a commercial potato chip slicer are cooked in the hot oil until crisp and a light golden brown whereupon the cooked potato chips are removed from the oil and allowed to drain. Upon analysis the chips are found to contain 6.0 mg. of zinc, 7.2 mg. of iron and .8 mg. of copper in the form of proteinates per 2 ounce serving of potato chips.

EXAMPLE XXVII Into a small container equipped with a stirrer containing hydrogenated corn oil is added a mixture of iron magnesium and zinc proteinates in an amount sufficient to provide 1.5 grams of iron, .5 grams of magnesium and 1.2 grams of zinc per gallon of oil. The oil is maintained at a temperature of about 4000 F. and is constantly agitated. A yeast leavened donut dough is cooked in the hot oil until done and the donuts are allowed to drain. Upon analysis it is shown that the donuts contained about 9.7 mg. of iron, 3.2 mg. of magnesium and 7.8 mg. of zinc for 4 ounce serving.

EXAMPLE XXVIII Into a vat that constantly strains and recirculates the oil is added a mixture of iron, manganese, copper and calcium proteinates in an amount sufficient to provide about .5 grams of each metal in the form of a proteinate in the oil. The oil is maintained at a temperature of about 325350 . Chicken legs are dipped in a batter and placed in the oil until cooked and are then removed and allowed to drain. Upon analysis it is shown that the proteinates are absorbed onto the surface of the batter in an amount of which is approximately proportionate to the concentration of the proteinates in the cooking oil.

The meat and meat flavored products which can be fortified by the metal proteinates are too numerous to enumerate. Virtually any recipe may be used as may any type or kind of meat, both domestic and wild. Typical of such products are swiss steaks, stews, processed meats such as bologna, salami and canned or potted meats, steaks, chops, roasts, hamburger, sausage, textured vegetable protein and like products. Such products may contain about .00001 to .01% by weight metal as a metal proteinate.

The metal proteinates may erihance the flavor of the product but are not to be considered as substitutes for seasonings, spices or other flavor enhancing materials.

The following examples are illustrative.

EXAMPLE XXIX A ten ounce beef steak was prepared for broiling by seasoning with two grams of salt and adding to the steak a mixture of comminuted metal proteinates wherein the metal content in the proteinates was 7.5 mg. zinc, 9 mg. iron and 1 mg. copper.

The steak was seasoned and then broiled until cooked. The steak contained five percent of the RDA of each mineral added as a metal proteinate.

EXAMPLE XXX A stew was made by mixing together 21bs. of stew meat; 1 cup water; 2 teaspoonsful meat drippings, 4 chopped green peppers; 6 carrots thickly sliced; dash of thyme, rosemary and basil; 1 head cauliflower; 2 onions; 2 bay leaves; 1 can tomato sauce; and 54 mgs. zinc 45 mgs. iron and 6 mgs. copper in the form of zinc, iron and copper proteinates. The stew was allowed to simmer until cooked. The stew served six people each serving containing five percent of the RDA of each metal added as a proteinate.

EXAMPLE XXXI A "Chili Pepper Surprise" was prepared from wild game by combining 2 Ibs.

venison, .5 Ibs. processed cheese, 2 medium chopped onions, pepper to taste, 1 can green chili peppers, .5 can condensed milk, .25 teaspoon garlic powder, .5 teaspoon celery salt and 45 mgs. iron as an iron amino acid chelate. The mixture was cooked and divided into six servings. Each serving contained five percent of the RDA of iron as an iron proteinate. If desired 2 Ibs. of a meat flavored soya flour extender could be used instead of, venison.

While many more examples or recipes could be added it is believed that the above are sufficient to properly describe this portion of the invention. However, many more applications will be obvious to one skilled in the art.

Another convenient way of adding essential metals to foods is by combining metal proteinates with seasonings and spices. Almost any seasoning or spice may be used. However alkali metal salts such as sodium chloride (bakers salt), potassium chloride and monosodium glutamate are preferred. Bakers salt may be flavored with onion, garlic and other conventional flavorings. The metal proteinate may contain a metal content for each metal present as a proteinate ranging from .001 to 0.1/ by weight of the seasoning or spice. As it will be seen from the following examples biologically essential metals chelated with tripeptides, dipeptides, and amino acids are stable with nutrients. Potato chips, corn chips, nuts, spice cookies, or cakes or virtually any other foodstuff upon which a seasoning or spice is placed may be used.

In certain cases the metal proteinates delays spoilage. That is, convey longer shelf life to a product than corresponding products not containing the metal proteinates.

The following examples are included for illustration.

EXAMPLE XXXII Potato chips are made by peeling and slicing potatoes into the desired sizes.

They are then deep fried in an oil such as hydrogenated palm oil. After they are removed from the cooking oils, they are flavored to taste with a fortified bakers salt. The following experiment was carried out in a commercial potato chip plant utilizing commercial seasoning equipment. Since a serving of potato chips approximates two ounces (57 grams) that was used as a standard. Onto each two ounces of hot cooked potato chips was added a mixture consisting of 1.14 grams of NaCI being fortified with amino acid chelates sufficient to provide 7.5 mg. zinc, 9.0 mg. iron and 1.0 mg. copper. Each metal therefore constitutes approximately 5/ of the RDA (recommended daily allowance) per serving.

Palatability or taste studies were conducted with fifteen volunteers on a double blind basis so that those administering the tests and those tasting the potato chips did not know which were the salt fortified potato chips and which were those having plain sodium chloride. After a series of tests 97% of the testing data resulted in an indication that the fortified potato chips had a superior taste quality over the controlled chips. Only 3/ of the tests detected no difference.

In addition to taste superiority, storage and rancidity studies on the treated chips as compared to the controlled chips demonstrated that the fortified or treated chips had two weeks longer shelf life than the controlled chips.

EXAMPLE XXXIII Compatability studies for a period of twelve months with bakers salt fortified with an iron amino acid chelate showed no oxidation or reduction of the chelates.

Moreover, the chelates are not hydroscopic or deliquescent.

The above studies could be equally applied to other seasonings such as bacon flavored, barbecued flavored and onion flavored salts applied to potato chips or other materials.

* A category of food products deficient in essential metals are those consisting primarily of sugar. As it will be seen from the following examples biologically essential metals chelated with tripeptides, dipeptides, and amino acids are stable with candies, jams, jellies, syrups, marmalades, toppings, or virtually any other sugar product.

In certain cases the metal proteinates may delay spoilage. That is, convey longer shelf life to a product than corresponding products not containing the metal proteinates. The amount of each metal in the product in the form of a metal proteinate may vary from about .001 to 1.0/ by weight of the product.

The following examples are included for illustration.

EXAMPLE XXXIV A caramel candy was made by buttering the sides of a large kettle and mixing together 2 cups of sucrose and one pint of cream. The mixture was brought to a boil for (3) three minutes in the kettle. One more pint of cream was slowly added to the hot mixture until the mixture was homogeneous. There was then added 2 oz.

coconut butter and .5 teaspoons salt. One and one thirds cup of hot glucose was added with stirring and the mixture was cooked to a temperature of about 250"F.

The hot mixture was removed and allowed to cool slightly whereupon 1 teaspoon of vanilla was added along with 9.1 grams of zinc proteinate containing 10/ zinc and 37.1 grams of an iron proteinate containing 12/ iron. The vanilla and metal proteinates were blended in to form a uniform mixture. The caramel thus formed was poured on a cool oiled platter and rolled into rolls about one inch in diameter and sliced into one-half inch slices.

EXAMPLE XXXV A caramel syrup for use as a topping was prepared by boiling one quart of maple syrup. One pint of cream was added to the hot syrup with constant stirring.

One cup of boiling glucose was then added with mixing. The syrup was cooked to 200"F. and was allowed to partially cool whereupon I teaspoon of vanilla was added along with 30.3 grams of a copper proteinate containing 15/ copper. The syrup was poured into containers and chilled.

EXAMPLE XXXVI An apple jelly was prepared by covering sliced apples with peel intact with water and cooking until the apple slices were soft. The cooked apple-water mixture was pressed through a jelly bag to produce a clear apple juice. Four cups of juice and 3 cups of sucrose were heated and boiled rapidly to 2200 F. and then removed from the heat. A zinc proteinate containing 10/ zinc was added to produce a jelly having .005% zinc content was poured into clean sterilized containers and sealed with a paraffin wax.

EXAMPLE XXXVII Peach jam was prepared by cooking well ripened peach slices until the peaches were easily crushed into a pulp. Equal volumes of peach-pulp and a sucrose were mixed and cooked over low heat for 20 to 30 minutes to obtain the desired consistency. A mixture of zinc and manganese proteinates was added to give a peach jam having a zinc content of .01/ and a manganese content of .005/. The hot jam was sealed with paraffin wax in sterilized glass jars.

WHAT I CLAIM IS: 1. A method of raising the level of biologically essential metals having a valency of +2 or greater in the tissues of warm blooded domestic animals which comprises administering at least one metabolically assimilable metal proteinates to said animals each said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

2. A method as claimed in Claim 1, wherein the metal in the metal proteinate is selected from calcium, magnesium, zinc, iron, manganese, copper, cobalt, molybdenum, chromium and vanadium.

3. A method as claimed in Claim 1 or 2, wherein the proteinate is administered with a suitable carrier in the form of a tablet, capsule, syrup, food additive or dietary supplement.

4. A method as claimed in Claim 1, 2 or 3, wherein each metal proteinate is administered in a dosage sufficient to correct an existing metal deficiency in the animal.

5. A method as claimed in Claim 4, wherein the existing metal deficiency is determined by analysis of the tissue of the animal to which the metal proteinate is to be administered.

6. A method as claimed in any preceding claim, wherein each metal proteinate is administered in the form of a buffered metal proteinate.

7. A method as claimed in Claim 6, wherein the buffer is selected from phosphates, carbonates, bicarbonates, amino acids mixed with bases and mixtures thereof.

8. A method as claimed in Claim 6 or 7, wherein the pH is from 7 to 11.

9. A method as claimed in Claim 7, wherein the buffer is a mixture of sodium carbonate and sodium bicarbonate.

10. A method as claimed in Claim 7, wherein the buffer is a mixture of one or more amino acids with sodium hydroxide.

11. A method of raising the level of biologically essential metals having a valency of +2 or greater in the tissues of warm blooded domestic animals as claimed in any preceding claim, substantially as hereinbefore described and exemplified.

12. A method for treating anemia in piglets which comprises administering a metal proteinate in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids, to a farrowing sow during the latter stages of pregnancy and during lactation.

13. A method as claimed in Claim 12, wherein the metal proteinate is an iron proteinate in admixture with other metal proteinates selected from magnesium, zinc, copper and cobalt proteinates.

14. A method as claimed in Claim 13, wherein the metal proteinate is exclusively an iron proteinate.

15. A method for treating anemia in piglets as claimed in any one of Claims 12, 13 or 14, substantially as hereinbefore described and exemplified.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (68)

**WARNING** start of CLMS field may overlap end of DESC **. added along with 30.3 grams of a copper proteinate containing 15/ copper. The syrup was poured into containers and chilled. EXAMPLE XXXVI An apple jelly was prepared by covering sliced apples with peel intact with water and cooking until the apple slices were soft. The cooked apple-water mixture was pressed through a jelly bag to produce a clear apple juice. Four cups of juice and 3 cups of sucrose were heated and boiled rapidly to 2200 F. and then removed from the heat. A zinc proteinate containing 10/ zinc was added to produce a jelly having .005% zinc content was poured into clean sterilized containers and sealed with a paraffin wax. EXAMPLE XXXVII Peach jam was prepared by cooking well ripened peach slices until the peaches were easily crushed into a pulp. Equal volumes of peach-pulp and a sucrose were mixed and cooked over low heat for 20 to 30 minutes to obtain the desired consistency. A mixture of zinc and manganese proteinates was added to give a peach jam having a zinc content of .01/ and a manganese content of .005/. The hot jam was sealed with paraffin wax in sterilized glass jars. WHAT I CLAIM IS:

1. A method of raising the level of biologically essential metals having a valency of +2 or greater in the tissues of warm blooded domestic animals which comprises administering at least one metabolically assimilable metal proteinates to said animals each said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

2. A method as claimed in Claim 1, wherein the metal in the metal proteinate is selected from calcium, magnesium, zinc, iron, manganese, copper, cobalt, molybdenum, chromium and vanadium.

3. A method as claimed in Claim 1 or 2, wherein the proteinate is administered with a suitable carrier in the form of a tablet, capsule, syrup, food additive or dietary supplement.

4. A method as claimed in Claim 1, 2 or 3, wherein each metal proteinate is administered in a dosage sufficient to correct an existing metal deficiency in the animal.

5. A method as claimed in Claim 4, wherein the existing metal deficiency is determined by analysis of the tissue of the animal to which the metal proteinate is to be administered.

6. A method as claimed in any preceding claim, wherein each metal proteinate is administered in the form of a buffered metal proteinate.

7. A method as claimed in Claim 6, wherein the buffer is selected from phosphates, carbonates, bicarbonates, amino acids mixed with bases and mixtures thereof.

8. A method as claimed in Claim 6 or 7, wherein the pH is from 7 to 11.

9. A method as claimed in Claim 7, wherein the buffer is a mixture of sodium carbonate and sodium bicarbonate.

10. A method as claimed in Claim 7, wherein the buffer is a mixture of one or more amino acids with sodium hydroxide.

11. A method of raising the level of biologically essential metals having a valency of +2 or greater in the tissues of warm blooded domestic animals as claimed in any preceding claim, substantially as hereinbefore described and exemplified.

12. A method for treating anemia in piglets which comprises administering a metal proteinate in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids, to a farrowing sow during the latter stages of pregnancy and during lactation.

13. A method as claimed in Claim 12, wherein the metal proteinate is an iron proteinate in admixture with other metal proteinates selected from magnesium, zinc, copper and cobalt proteinates.

14. A method as claimed in Claim 13, wherein the metal proteinate is exclusively an iron proteinate.

15. A method for treating anemia in piglets as claimed in any one of Claims 12, 13 or 14, substantially as hereinbefore described and exemplified.

16. A composition for raising the level of biologically essential metals having a

valency of +2 or greater in the tissues of animals, comprising a carrier and at least one metabolically assimilable metal proteinate, each said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

17. A composition as claimed in Claim 16, wherein the metal in the metal proteinate is selected from calcium, magnesium, zinc, iron, manganese, copper, cobalt, molybdenum, chromium and vanadium.

18. A composition as claimed in Claim 16 or 17, wherein the composition is in the form of a tablet, capsule, syrup, powder, granule or pellet.

19. A composition as claimed in Claim 16, 17 or 18, additionally including a buffer.

20. A composition as claimed in Claim 19, wherein the buffer is selected from phosphates, carbonates, bicarbonates, amino acids mixed with bases, and mixtures thereof.

21. A composition as claimed in Claim 19 or 20, wherein the pH is from 7 to 11.

22. A composition as claimed in Claim 20, wherein the buffer is a mixture of sodium carbonate and sodium bicarbonate.

23. A composition as claimed in Claim 20, wherein the buffer is a mixture of one or more amino acids with sodium hydroxide.

24. A composition for raising the level of biologically essential metals having a valency of +2 or greater in the tissues of animals, as claimed in any one of Claims 16 to 23 substantially as hereinbefore described and exemplified.

25. A bakery product containing a biologically essential metal having a valency of +2 or greater as a metal proteinate said proteinate being in the form of a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

26. A bakery product as claimed in Claim 25, wherein the metal is selected from iron, zinc, copper, magnesium, calcium, cobalt, manganese, molybdenum, chromium, vanadium and mixtures thereof.

27. A bakery product as claimed in Claim 25 or 26, wherein each metal is present in an amount ranging from 0.00001 to 0.001% by weight.

28. A bakery product as claimed in Claim 25, 26 or 27, wherein the metal proteinate is mixed with flour.

29. A bakery product as claimed in Claim 25, wherein the bakery product is bread.

30. A bakery product as claimed in Claim 25, wherein the bakery product is a cereal that has to be cooked.

31. A bakery product as claimed in Claim 25, wherein the bakery product is a prepared cereal.

32. A bakery product as claimed in Claim 25, wherein the bakery product is selected from pastry, cookies and cakes.

33. A bakery product as claimed in any one of Claims 25 to 32, substantially as hereinbefore described and exemplified.

34. A cooking oil containing a stabilizing amount of at least one metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

35. A cooking oil as claimed in Claim 34, wherein the metal proteinate is selected from iron, zinc, copper, cobalt, manganese, magnesium, calcium, molybdenum, chromium, and vanadium proteinate.

36. A cooking oil as claimed in Claim 34 or 35, wherein the metal content of each metal in the metal proteinate is from 0.2 to 2.0 grams per gallon of oil.

37. A cooking oil as claimed in Claim 34, 35 or 36, substantially as hereinbefore described and exemplified.

38. An oil cooked edible food containing a biologically essential metal having a valency of +2 or greater in the form of a metal proteinate wherein said metal proteinate is absorbed onto said food from the cooking oil and wherein said metal protein ate is a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides, and naturally occurring amino acids.

39. An oil cooked edible food as claimed in Claim 38, wherein the metal proteinate is selected from iron, zinc, copper, cobalt, manganese, magnesium, calcium, molybdenum, chromium and vanadium proteinate.

40. An oil cooked edible food as claimed in Claim 38 or 39, wherein the cooking oil contains from 0.2 to 2.0 grams of metal per gallon and the amount of metal chelate in the food will be approximately proportionate to the concentration of the metal proteinate in the oil absorbed by the food.

41. An edible food as claimed in Claim 38, 39 or 40, wherein the food is potato chips.

42. An edible food as claimed in Claim 38, 39 or 40, wherein the food is french fries.

43. An edible food as claimed in Claim 38, 39 or 40, wherein the food is a pastry.

44. An edible food as claimed in Claim 38, 39 or 40, wherein the food is a batter covered meat product.

45. An oil cooked edible food as claimed in any one of Claims 38 to 44, substantially as hereinbefore described and exemplified.

46. A product comprising a meat or meat flavored vegetable derivative containing a biologically essential metal having a valency of +2 or greater in the form of a metal proteinate or a mixture of metal proteinates, wherein each said metal proteinate is a chelate of said metal with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

47. A product as claimed in Claim 46, wherein the metal in the metal proteinate is selected from zinc, iron, copper, manganese, magnesium, cobalt, calcium, molybdenum, chromium and vanadium.

48. A product as claimed in Claim 46 or 47, wherein the metal content of each metal contained in said product as a proteinate is from 0.00001 to 0.01% by weight of said product.

49. A product as claimed in Claim 46, 47 or 48 substantially as hereinbefore described and exemplified.

50. A seasoning salt or spice which has been fortified with metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

51. A seasoning salt or spice as claimed in Claim 50, wherein the metal proteinate is selected from iron, zinc, copper, cobalt, manganese-, magnesium, calcium, molybdenum, chromium and vanadium proteinate.

52. A seasoning salt or spice as claimed in Claim 50 or 51, wherein the metal content of each metal in the metal proteinate is from 0.001 to 0.1/ by weight of the seasoning or spice.

53. A seasoning salt as claimed in Claim 50, 51 or 52, wherein said seasoning is a sodium or potassium salt.

54. A seasoning salt as claimed in Claim 53, wherein the sodium or potassium salt is selected from sodium chloride, potassium chloride and monosodium glutamate.

55. A seasoning salt or spice as claimed in any one of Claims 50 to 54 substantially as hereinbefore described and exemplified.

56. A food product containing on the surface thereof a seasoning salt which has been fortified with at least one metal proteinate wherein said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides, and naturally occurring amino acids.

57. A food product as claimed in Claim 56, wherein the metal proteinate is selected from iron, zinc, copper, cobalt, manganese, magnesium, calcium, molybdenum, chromium and vanadium proteinate.

58. A food product as claimed in Claim 56 or 57, wherein the seasoning salt is selected from sodium chloride, potassium chloride and monosodium glutamate.

59. A food product as claimed in Claim 56, 57 or 58, wherein the food product is a potato chip.

60. A food product as claimed in any one of Claims 56 to 59, substantially as hereinbefore described and exemplified.

61. A food product comprising a sugar as the principal ingredient and containing a metal proteinate or mixture of proteinates wherein each said metal proteinate is a chelate of a biologically essential metal having a valency of +2 or greater with at least two protein hydrolysate ligands selected from tripeptides, dipeptides and naturally occurring amino acids.

62. A food product as claimed in Claim 61, wherein the metal proteinate is selected from iron, zinc, copper, cobalt, manganese, magnesium, calcium, molybdenum, chromium and vanadium proteinate.

63. A food product as claimed in Claim 61 or 62, wherein the metal content of the metal proteinate is from 0.001 to 1.0% by weight of the food product.

64. A food product according to Claim 61, 62 or 63, wherein the food product is a candy.

65. A food product as claimed in Claim 61, 62 or 63, wherein the food product is a jelly.

66. A food product as claimed in Claim 61, 62 or 63, wherein the food product is a jam.

67. A food product as claimed in Claim 61, 62 or 63, wherein the food product is a syrup or topping.

68. A food product as claimed in any one of Claims 61 to 67 substantially as hereinbefore described and exemplified.