Background of the invention

Field of the invention

The present invention relates to a food composition which is capable of preventing oxida- tion of fatty acids and has high protein content. The present invention also relates to a method suitable for the production of such food composition or product containing it, as well as products prepared by such method.

This food composition is suitable for a variety of uses. It can be utilized among other things in baking and production of meat products and convenience food. In addition to foods, it is also suitable for drug and cosmetic industry to improve compositions of the products.

Description of related art Proteins consists of amino acids and they are known to be naturally in a kink due to the bonds formed by amino acids between each other, by particular generally known mechani cal or other chemical etc. treatments, protein structures can be better opened to benefit among other pharmaceutical, bio and food industries. Hence, proteins can be used at inter faces of different chemical mediums and use those as emulsifier ingredients. Typically, different protein-rich raw-materials obtained either from plant or living organism are used in the industry. Raw-materials are usually processed and treated in such a way that the nat ural kink structure of proteins is opened and protein content is increased by generally known methods. Hence, proteins act better in industrial processes, they are among other more soluble and mix more easily with other raw-materials.

In addition to nutritional purpose, protein is used for its functional properties. Depending on the protein used and its properties, an emulsion is obtained. Typically, emulsions are produced by different homogenizers and mixers. In general, the problem has been found to be the weakening of strength, stability and uniformity of emulsion structures due to too mild mechanical treatment (mixing).

In patent CN103651677 (B) has been described a production of micro emulsion as improv ing factor of industrial production of food and especially production of bread. In the patent, a composition of water and oil phase, LACTEM additive and two different form of citric acid glyceride has been described, which composition is carried out by fast mixing at a temperature of 35 to 65 °C, components are mixed by high pressure homogenizer. After this, the mixture is cooled to room temperature and processes with a significant high pres sure treatment for 30 seconds to 30 minutes, wherein monoester content of the LACTEM ingredient is above 80 % and citric acid glycerides content is above 60 % of total esters.

In patent CN103054042 (B) has been described a micro emulsion, which is formed by linoleic acid and is suitable for food, and its production in which the emulsion acts as a carrier. The composition includes 0.5 to 20 weight-% Tween20-ethanol mixture, 0.5 to 9 weight-% linoleic acid and 71 to 99 parts water. The production is made in constant stir ring, wherein the Tween20-ethanol mixture is added gradually at certain weight- proportions, then the linoleic acid is added and finally water. Hence, a transparent uniform mixture system is obtained, which system is the required micro emulsion carrier. Thus, the insolubility of linoleic acid into water phase is solved and a reduced particle size of the micro emulsion is obtained.

In publication CN106692050 (A) has been presented a production method and composition of enteral nutritional micro emulsion. The micro emulsion contains 0.5 to 5 weight-% pro tein, 36 to 61 weight-% fat, 8 to 30 weight-% minerals calculated form the emulsion and 5 to 30 weight-% emulsifier. The composition may solve problems associated with cohe siveness and stability of traditional emulsions caused by large particle sizes and presence of water phase. In addition, among other things solubility and bioavailability of nutrients are improved.

In patent ETS5891490 has been presented eatable oil-in-water micro emulsion, which pro vides crispness and browning surface to microwave treated food coated by it. Proportion of water in the composition is 80 weight-%, proportion of oil is below 10 weight-% and at least one non-ionic surface-active material is used in the composition. The invention present in patent application FI20175435 relates to a food fat component which is capable to prevent oxidation of fatty acids and simultaneously improve both nutri tional profile and organoleptic properties of the product. The invention also relates to method suitable for production of such component, and products in which this component has been utilized. In this invention the prevention of oxidation of fatty acids is based on physical barrier and antioxidants possibly contained in the ingredients. Such food fat com ponent is suitable for variety of uses. It can be utilized for example in minced beef, choco late masses and pies, and in addition to these it is suitable for pharmaceutical and cosmetic industries to improve compositions of products.

Proteins function in the body ^' s enzymes, tissue structures, hormones and antibodies. Pro teins consist of amino acids, and they supply the necessary amino acids from the nutrition to the body. Proteins contain 20 different amino acids. Nine of these are necessary i.e. they are needed from food, the rest 1 lean be build up in the body from compounds containing carbon and nitrogen or formed from necessary amino acids. Necessary amino acids (histi dine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and va line) for human needed from food are easily available from animal origin food proteins. The intake of proteins from food is often clearly higher than the minimum requirement, and deficiencies do not occur in healthy people. Vegetable food proteins are also versatile in amino acids. However, when using only ordinary vegetables, the intake of lysine, me thionine and threonine amino acids may remain scarce. The situation improves if the diet contains enough legumes, nuts and seeds.

Proteins of nutrition degrade in the digestive tract into amino acids which absorb and inter fere with the amino acids from body ^' s own proteins. Part of the amino acids are free in bloodstream, while part is used as body ^' s proteins. Amino acids are transferred between the free storage and the proteins in both directions and they form other nitrogen-containing compounds, such as purines, creatine and hormones, such as adrenaline. Part of the amino acids is degraded and used either as in energy metabolism or stored as carbohydrates or fat. When the protein intake is higher than the need, they are used for satisfaction of energy need in the same way as carbohydrates. The energy value of proteins and amino acids cor responds to carbohydrates (17 kJ/g). Nitrogen-containing parts of compounds eventually produce ammonia in the kidneys. A method described in publication CN101878904 (A) produces a gel-like wheat protein emulsion. The method consists of the following steps: wheat protein condensate or isolate is dispersed with distilled water (solid/solution ratio 0.8 to 1.5: 10) and the mixture is dehy drated for 6 to 12 hours, wherein a soluble dispersion is obtained. By heating the mixture for 0.3 to 1.0 hours at a temperature of 70 to 75 °C and mixing the dispersion to vegetable oil at a ratio of 8 to 4:2 to 6 and continuing a vigorous homogenization treatment a coarse protein emulsion is obtained. Finally, Microjet-homogenization gives a milky light emul- sion. The method advantages include among other simplicity, low costs, safety and envi- ronmental friendliness. The produced emulsion can be applied in different nutritional and functional foods and it can act as a carrier of fat-soluble drugs.

In application W02005112657 (Al) has been described a method for processing of amino acid-enriched proteins and protein hydrolysates into functional and medical foods. In the method, protein and endopeptidase contained in it or added as a separate mass are mixed at a temperature of 20 to 51 °C or at certain temperature of optimal enzyme, at pH 2 to 7, to one or more of the following amino acids: LYS, ARG, PHE, TYR, TRP, THT, CYS, GLU, ASP, MET, ALA, VAL, GLY, LETT, ILEET. The dry-matter content of the preparation var ies in the production between 10 to 40 %. The mixture is diluted with water and pH is ad justed to range of 2 to 7.

Summary of the invention

The present invention is defined in the independent claims. Certain embodiments are de fined in the dependent claims.

According to a first aspect the present invention relates to a food composition which is ca pable to prevent oxidation of fatty acids, and has high protein content.

According to a second aspect the invention relates to a product wherein the above de scribed food composition is used to simultaneously improve both organoleptic properties and nutritional profile of the product, enabling especially a favorable amino acid profile.

According to a third aspect the invention relates to a method for the production of the above described food composition. According to a fourth aspect the invention relates to the use of a food composition or prod- uct according to the invention.

The invention enables the improvement of protein and amino acid content of products sim ultaneously with the prevention of oxidation of fatty acids. Especially raw-materials natu- rally containing protein are used in the invention and they are treated into suitable technical conformation, i.e. such a way that their native form releases i.e. the natural kink structure opens, wherein the proteins are beneficial in the formation of micro emulsion, wherein they are easy to process into homogenous mass by generally known methods.

The method according to the present invention and the composition produced by it enables the protection of soluble fat against oxidation. In the present invention the prevention of oxidation of fatty acids is based on physical barrier and antioxidants optionally contained in the ingredient. The method of the invention allows the preservation of the nutritional quality of soluble fats as well as the prevention of primary oxidation and hence preferably improvement of the quality of fatty acids in the products compared with normal orally con sumed products containing soluble fat.

Several benefits are achieved with the present invention. The invention enables combining of functional properties, nutritional need and novel production method of protein in novel manner and ensuring more likely progress of the reaction with sufficient heat energy, wherein the final composition is a preparation containing protein and especially also essen tial amino acids, which preparation can be the final product or other food raw-materials containing protein can be added thereto to obtain the final product. The product according to the invention contributes to the metabolism of tissues and cells and gives a feeling of satiety.

A similar composition wherein the prevention of oxidation of soluble fats is combined in a new inventive manner favorably with proteins or amino acids has not been previously de scribed. Embodiments

The present invention relates to a food composition and method for producing this compo sition, which composition is capable to prevent oxidation of fatty acids and which also has high protein content, thereby improving nutritional and organoleptic properties of product.

The food composition comprises a food fat component and mechanically or by heating processed protein mass, three-dimensional structure of which is partly or completely opened as a result of processing.

According to a preferred embodiment the food fat component comprises an oil-in-water - type homogenate with which the protein mass is blended and the mass is dispersed by vig- orous mechanical treatment.

Mechanically or by heating processed protein mass has surprisingly found to stabilize the oil-in-water mixture formed in the production of the food fat component presented in pa tent application FI20175435 and to enhance its protective effect on fats in the food fat component.

According to another embodiment the food fat component used in the food composition is the oil-in-water mixture described in the patent application FI20175435.

Patent application FI20175435 describes an oily fat and grain containing food fat compo nent and a product including it, as well as a production method of these. The patent appli cation relates to a food fat component which is capable to preventing oxidation of fatty acids and simultaneously improving both the nutritional profile and organoleptic properties of the product. In said patent application the prevention of oxidation of fatty acids is based on a physical barrier and antioxidants optionally contained in the ingredients.

According to the mentioned patent application the function of the fat component is based on the idea that after the addition of protein and biomaterial (optionally also addition of electrolyte) to the oil-in-water mixture the fatty acids contained in the fat are bound by means of a mechanical treatment and assisted by the proteins into small particles, where upon the proteins and the active chains of their amino acids are via their affinities and part- ly via interatomic bonds contorted onto the surface of the particles. Also other biomaterial may be added to the mixture, after which the mixture is dehydrated, whereupon a finished food fat component is formed. By forming the oil-in-water mixture prior to addition of pro- tein, the oil and fatty acids have been rendered into stable protected structures, i.e. the fat remains in the product without detaching and causing an unpleasant mouthfeel. With the decrease of water as a result of dehydration, the preservability of the food fat component is enhanced and oxidation of fats can simultaneously be reduced. Both the nutritional and organoleptic properties of the products can be improved by means of the presented food fat component.

According to a preferred embodiment, it is significant for the present invention to first form a mixture of oil and water, and optionally electrolyte. Oil-in-water mixture is formed by mixing oil effectively into the water, in which mixture small oil droplets are evenly mixed with the water. The system thus formed is, however, not stable because oil repels water and small oil droplets easily combine, wherein two separate phases are quickly formed.

Thus, protein should be added to the oil-in-water mixture where the oil droplets are still evenly distributed in the water phase.

Proteins are polar compounds with both hydrophilic and lipophilic parts. According to a preferred embodiment, a water soluble protein is used in the present invention. When water soluble protein is added to above described oil-in-water mixture, the lipophilic parts of the protein seek on to the surface of the oil droplets before water molecules have time to form a shell around the protein, which shell weakens the interaction between protein and oil droplets. Thus, a protein membrane, in which the hydrophilic part of the protein is out ward, is formed around the oil droplets. The hydrophilic part is surrounded by water mole cules of the water phase by binding these tightly into the composition, which prevents dry ing of the food fat component during both storage and heating. Oil-in-water emulsion is formed, in which emulsion protein preferably acts as an emulsifier.

According to a preferred embodiment the food composition according to the invention comprises the food fat component according to the patent application FI20175435, in which component is blended the pre-treated protein mass. According to another embodiment the food composition according to the invention com prises the first part of the food fat component according to the patent application

FI20175435, which part comprises an oil-in-water mixture and protein, and into which has been blended the pre-treated protein mass.

According to a third embodiment the food fat component according to the invention com prises the oil-in-water mixture of food fat component according to patent application FI20175435, into which mixture is blended the pre-treated protein mass.

Generally, in the present invention, when talking about a food fat component, it refers to the food fat component according to patent application FI20175435 or any part of it, which parts have been described above.

Typically, protein mass contains protein and water contained in the biomaterial.

According to one embodiment the used protein raw-material is plant based.

According to another embodiment the pre-treated protein mass contains any protein-rich raw-material of animal origin, such as fractions containing protein obtained from various plant products, such as beans, lentils, seeds, grains, or insects, seafood, chordates, mam mals, fungi, algae or molds, or from protein-rich raw-material obtained from any mixture of these.

According to a preferred embodiment the protein mass is blended into the food fat compo nent or into part of it in homogenous form.

According to one embodiment the proportion of the pre-treated protein mass in the food composition is typically 10 to 70 weight-%, preferably 10 to 50 weight-%.

According to one embodiment total protein content of the food composition is typically 10 to 50 weight-%, preferably 15 to 45 weight-%. The total protein content comprises both pre-treated protein and protein in native form. The present invention also relates to a method for production of the above described food composition.

According to preferred embodiment of the method, biomaterial containing protein is pre diluted and heated preferably in such a way that the native sheet structures of protein open partly or completely, and the obtained mixture is homogenized by vigorous mechanical treatment. In the method according to the invention, homogenous mass containing protein is mixed into the food fat component or into any part of it.

According to a preferred embodiment the method according to the invention comprises addition of protein in one or more stages, for example in two or three stages. Typically, protein is added right at the beginning, as pre-treated protein mass, and possibly as native protein in one or more stages at later stage of the method.

Protein in native form can be added for example to oil-in-water mixture and/or right at the end of the production process with the last possible addition of biomaterial.

According to one embodiment, in the first stage of the method a protein mass is produced, which mass functionally helps the formation of micro emulsion. The produced protein mass is combined to the food fat component, after which in the actual second stage of the process protein-rich plant-derived raw-material is added to the composition thus formed, wherein a preparation high in protein can be produced, which preparation can be used as such or as a part of industrial production of other food.

According to one embodiment, in the first stage of the invention when protein mass is pro duced, mass containing protein is pre-diluted and heated. After the first stage, in the first mixing stage, water, vegetable oil and possibly electrolyte are added to the protein mass. The obtained mixture is homogenized with vigorously cutting blades, wherein a homoge nous mass is obtained. In the second mixing stage, raw-material containing protein is mixed to the homogenous mass and optionally the obtained mixture is dehydrated with heat.

The product is rendered into desired degree of fineness by generally known methods. The product can be used as such or it can be added as a component to food to be prepared. If necessary, lecithin is mixed with the fat phase, which lecithin can be used to affect the po- larity of the fat phase.

According to one embodiment the food fat component and its production method described in above mentioned patent application is used in the present invention. Typically, this food fat component comprises 10 to 70 weight-% oil fat, 10 to 70 weight-% biomaterial and 1 to 40 weight-%, preferably 1 to 30 weight-% protein. In addition, the component typically comprises water and possibly electrolyte. For example salts can be used as electrolytes.

According to a preferred embodiment water content, or more precisely moisture content, of a finished food fat component is typically 0.1 to 15 weight-%. Appropriate moisture can have a reducing effect on the oxidation of fatty acids. In addition, its advantages include, for example, non-dustiness and fluidity of the food fat component during use. Moisture can be in the form of pure water or some other aqueous liquid. Milk and vegetable and fruit juices are liquids typically suitable for this purpose.

As biomaterial in the production of the food fat component, use is typically made of carbo hydrate containing, but also protein and fat containing, biomaterial. As examples, mention can be made of cereal flours, semolina or flakes (such as wheat, barley, rye, oats, spelt, millet, maize, rice or sorghum); pseudocereal flours, semolina or flakes (such as buck wheat, amaranth or quinoa); legumes (soybeans, peas, chickpeas, beans, lentils, lupines) or field beans. The ingredients of the component form an oil-in-water emulsion, in which pro tein and biomaterial form, as a result of intensive homogenizing, a stable structure on the interfaces of the emulsion. By dehydrating the emulsion, a powder-like solid material is obtained.

According to a preferred embodiment, as biomaterial in the production of the food fat component, use is made of starch based material, such as oats, maize, rice, potato, vegeta ble powder or tapioca starch, or any mixture of these, preferably oats.

Any fat which at least upon heating is oil-like is suitable as the oil fat for use in the present invention. In fact, various different fats or lipid compounds can be used for the production of the component according to the invention, i.e. by using the method, different fat profiles can be generated for various orally consumed fat-containing biomatrices. As oil fat, use is typically made of vegetable fat or oil, such a s rapeseed or palm oil, shea butter, or a com bination of these. Omega fatty acids are particularly beneficial.

Protein sources used in the food fat component are not restricted. Any protein obtainable from living organisms can be used in the invention (such as above mentioned flours, semo- lina and flakes, or insects, seafood, chordates, mammals, fungi, algae or molds).

According to a preferred embodiment, the protein contained in the food fat component is a protein contained in egg, such as avidin, ovalbumin, conalbumin or lysozyme, or a soy pro- tein, or several of these simultaneously.

According to a preferred embodiment the protein source contained in the food fat compo- nent has a protein content of at least 50 %, preferably at least 80 %, for example about 90 %.

According to another preferred embodiment, encapsulation of fat is performed without added stabilizing or emulsifying agents in the method according to the invention, in con trast to several already patented fatty acid microencapsulation methods. Preferably, the protein source used serves itself as emulsifier, such as in the case of egg. According to one embodiment, a separate emulsifier can also be used. When producing vegan products, for example lecithin can be used.

According to a preferred embodiment biomaterial and protein comprised in the food fat component are specifically from different sources. This is due to that the protein source should be protein-rich because it is the function of the protein to form a protein membrane around the oil droplets by its polar structure containing both hydrophilic and lipophilic parts. In turn, biomaterial is preferably carbohydrate-rich in order to be able to fulfill its function among others by protecting the above described formed structure and acting as a moisture binder.

According to one embodiment biomaterial may also comprise protein and fat, but in that case use is preferably also made of additional protein source. According to a preferred embodiment the biomaterial other than the main protein source is carbohydrate-based.

Ingredients of the food fat component added in right, in the present invention defined, or der and mixed form an oil-in-water emulsion in which protein and biomaterial form, as a result of intensive homogenizing, a stable structure on the interfaces of the emulsion.

According to one embodiment the emulsion can be dehydrated, wherein a powder-like sol id material is obtained.

In the production method according to patent application FI20175435, a fat phase and salt are added into water to a water content of 20 to 80 weight-%, preferably 30 to 70 weight- %, and the mixture thus obtained is stirred at below 60°C, preferably below 50 °C, for less than 10 min. At the latest as a result of this heating the fat used will be in an oil-like form and an oil-in-water mixture has formed in which the fatty acids are dispersed in the aque ous phase. The pre-treated protein mass according to the invention can be added at this stage. Protein is added to the mixture, and mechanical stirring is then continued. At the final stage, intense homogenizing treatment is applied for less than 10 min, preferably less than 3 min, until the mixture consists of a homogenous phase or phases. The protein is added at a temperature below 100 °C, preferably 0 to 70 °C, depending on the protein source. When necessary, an electrolyte, typically salts, can additionally be added to the mixture. This phase/these phases constitute the first part of the food fat component accord ing to the invention. Homogenization of the mixture is carried out by a commonly known mechanical method which is compatible with the viscosity of the desired mixture. Homog enization is preferably carried out with mechanically cutting blades. Alternatively, the pre treated protein mass according to the invention can be added at this stage to the formed first part of the food fat component.

In the next step the mixture is combined with other biomaterial, wherein food fat compo nent according to patent application FI20175435 is obtained. Combining takes place by generally known mechanical treatments such as grinding, mixing, high pressure treatment, cutting treatment or a combination of these. The biomaterial must be hygienically clean and fulfill the requirements of generally acceptable standards. As the final result, a homog- enous mass, mixture or suspension is obtained. Alternatively, the pre-treated protein mass according to the invention can be added at this stage to the finished food fat component.

According to one embodiment, plant-based protein-containing dry matter, in a form of powder, can still be blended into the finished food composition in order to further increase protein content and mix the composition into viscous mass.

According to one embodiment the resulting mass, mixture or suspension is dehydrated by generally known and applicable processing methods (e.g. freeze-drying or vacuum drying), preferably by heat treatment. The heat treatment takes place typically at below 250 °C for a time of less than 45 min, depending on the viscosity of the mixture and the volume of the mixture to be processed. Dehydration enables the amount of water to be reduced in the product and the preservability of the product thus improved. Typically, the moisture, i.e. water content of the dehydrated product is about 0.1 to 15 weight-%, depending on the dry ing conditions. Dehydrated product is grinded by generally known methods to suitable par ticle size.

According to a preferred embodiment the resulting mass, mixture or suspension is dehy drated as a thin layer, particularly when using heat treatment. The thickness of the layer to be dehydrated is preferably less than 10 mm, for example about 2 to 8 mm, preferably about 5 to 6 mm.

According to one embodiment dehydration takes place through drying the mass, mixture or suspension e.g. by freeze-drying or vacuum drying at low temperatures.

According to another embodiment dehydration takes place through baking the mass, mix ture or suspension by heat treatment. Preferably heat treatment takes place under 250 °C.

Adjustment of pH is possible during the production process. Since pH is of great im portance as regards the functioning of proteins, it can be used to influence the behavior of proteins. At a favorable pH the functional capacity of proteins is highest, whereby they effectively bind fatty acids into small particles, preventing their oxidation. Adjustment of pH thus allows one to have an influence on the degree of oxidation of fatty acids and fur- ther on the nutritional profile of the product. For most proteins, the favorable functional pH is approximately 7 to 8.

According to one embodiment food composition according to the invention can be added as such to the desired product in the production stage of the product.

The following non-limiting examples represent applications of the present technology. In

PRODUCTION EXAMPLES

Example 1 - Production of food composition.

Step a) Such mixture was prepared, in which initially watered plant based raw-material containing protein was boiled and allowed to water. The mass was homogenized suitably by generally known mechanical methods.

Step b) Oil-in-water type homogenate was blended into the mass and the mass was dis persed by vigorous mechanical treatment.

Step c) Finally, plant-based protein-containing dry-matters, in a powder form, was blended into the mass and mixed into a viscous mass. The mass was suitably shaped and dehydrat- ed at a temperature of above 100 °C. The yield was dried by a generally known method.

Example 2 - Production of food composition

STEP 1 - Production of lentil mass

Mass containing lentils and water was boiled and the mass was minced smooth by general ly known methods.

Table 1. Lentil mass composition.

STEP 2 - First step in the production of the food fat component: production of the homog enate (described above) and combining it with the lentil mass of step 1.

Table 2. Homogenate composition.

STEP 3 - Addition of biomaterial intothe homogenate.

Table 3. Composition of added biomaterial and final food composition

STEP 4 - Drying.

The composition formed by steps 1 to 3 was dried at 180 °C for 10 to 40 minutes. Example 3 - Production of food composition. Example 3a. The oil-in-water type homogenate to be added in step b of example 1 were directly mixed with protein-containing flour. The obtained mass was dehydrated in heat and grinded.

Example 3b. The mass formed on the basis of steps a and b described in example 1 was mixed with plant mixture mass (lentil, pea, carrot) and small and bigger species were shaped from the mass. The pieces were frozen. Example 3c. The mass formed on the basis of steps a and b described in example 1 was mixed with plant mixture mass (lentil, pea, carrot) and small and bigger pieces were shaped from the mass. The pieces were cooked.

Example 3d. Oats, preservatives and water were added to the mass formed on the basis of steps a and b described in example 1, and a spread was made of the mixture. The spread was heat treated to improve the preservability.

Example 3e. Aqueous solution and emulsifiers and preservatives were added to the mass formed on the basis of steps a and b of example 1. The soluble mixture was heat treated and packed. The produced product was drinkable.

Industrial applicability

The present invention can be used in general for preparation of a food composition and product according to the invention.

In particular, the present invention is suitable for improving protein and amino acid content of foods. In addition, the food fat component described in patent application FI20175435 (Food fat component, its production method and its uses) provides favorable, among other organoleptic properties and nutrition profile of the product improving properties into the food composition. Thus, the food composition is in general suitable to be used especially in production of food products improving their health and organoleptic properties and provid- ing added value in a form of high protein content.

The products according to the invention can be produced in industrial scale. The invention is namely based on industrial production and industrially used vigorous process treatments.

The food composition can be used as an independent product or as part of a composition in various matrixes, such as in various bakery products, meat products and convenience foods. List of reference publications

Patent literature

CN101878904 (A)

CN103054042 (B)

CN103651677 (B)

CN106692050 (A)

US5891490 (A)

WO 2005112657 (Al)

Other literature

WHO (World Health Organization). 1985. Energy and Protein Requirements. Report of a Joint FAO/WHO/UNU Expert Consultation. Technical Report Series 724. World Health Organization, Geneva. 206 pp.