Title of Invention

IMPROVED DELIVERY OF BENEFET AGENTS

Abstract

A process for producing substantially encapsulated food additive particle comprising: a) an inorganic, porous core in which at least one water soluble functional ingredients is impregnated and b) a water insoluble outer coating comprising at least one multivalent metal salt of fatty acids wherein the fatty acid has a chain length not less than 8 and the melting point of the coating is greater than 100°C. said process comprising the steps of: a) forming the impregnated core by adding up to 90% of the pore volume of the inorganic porous material an aqueous solution of the water soluble functional ingredient; b) forming a coating of the multivalent metal salt of at least one fatty acid on the impregnated core. such that the encapsulated food additive particle thus formed has the pore volume of the porous core is from 2 to 5.5 ml/g, more preferably from 2.5 to 2.8 ml/g

Full Text

FORM -2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10) IMPROVED DELIVERY OF BENEFIT AGENTS HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the nature of the invention and the manner in which it is to be performed. TECHNICAL FIELD The present invention relates to substantially encapsulated functional ingredients and a process for making the same. BACKROUND TO THE INVENTION Functional ingredients are often known to be coated or encapsulated in the prior art. This is usually done to reduce adverse interaction between the ingredient and the product during incorporation of the ingredient into a product, processing of the product or storage of the product and to provide heat, pH and/or moisture resistance. Encapsulation or coating is also done to provide controlled or targeted release of the ingredient. Examples of such functional ingredients are perfumes, pigments, dyes,, flavours, vitamins and food functional ingredients. Several methods of coating or encapsulation are known in the art. These include physico-chemical processes like interfacial polymerisation, coacervation, phase separation from aqueous or organic solvents, forming meltable dispersions followed by coating and solidification and mechanical processes that include spray drying and vacuum coating. It is required that the coating be strong enough to withstand chemical and physical abuse and yet break down under appropriate conditions to release the functional ingredient. An exhaustive description of coating and encapsulation methods is provided in Microcapsule Processing and Technology, A. Kondo, ed. and revised J.W van Valkenburg, Marcel Dekker , New York and Basel, 1979. Coating materials may be water soluble or water insoluble. Examples of water soluble coatings include cellulose, hydroxyethyl cellulose, gelatin, casein, dextrin and carboxymethyl starch. Insoluble coating materials include silicates, clays and alkaline earth metal salts of fatty acids. However, it is often preferable to disperse the functional ingredient in a core material, followed by coating or encapsulation of the core. A common core material is a gel in which the ingredient is dispersed. Examples of such materials are methyl cellulose and gelatin. Porous, inorganic materials, examples of which are silica and zeolites have also been disclosed in the prior art as core materials. In particular, volatile organic compounds like flavours and perfumes and reactive compounds like bleaches can be dispersed inside the pores of the inorganic material, becoming available only during use. Functional ingredients like iodine containing compounds and vitamins are often added to food articles. However, they can be unstable under certain cooking conditions as well as during storage. For example, iodine containing compounds like potassium iodate reduce to elemental iodine in acidic pH and in the presence of reducing agents (e.g. spices used during cooking) and are thus unavailable to the body in the required form. Other functional ingredients like iron compounds and oligopeptides when incorporated into food preparations, often impart an undesirable colour or sensory properties either during storage or during use. It is therefore required that they be encapsulated in order that they do not interact with other food components and adversely affect the organoleptic properties. PRIOR ART US4671963 discloses foodstuffs coated with alkaline earth metal salts of stearic acid. The water insoluble coating helps to retain the original texture of the coated food in the presence of moisture. Preferred examples of such food stuffs are crunchy foodstuffs like cereal bars. The zinc, calcium or magnesium stearate is dissolved in hard fat and then applied to the cereal. The stearates may also be dusted on an oil containing cereal to provide a moisture resistant coating. IN 182558 and IN 1.82559 disclose methods to encapsulate iodine containing compounds. According to the inventions, a number of materials can be used to provide a protective coating to the iodine containing compound. The patents claim that such . encapsulated particles can be incorporated in common salt. US6030645 discloses particles that comprise an oleophilic substance dispersed in a matrix of at least one core material and a coating. The oleophilic material is vitamin A or E. The core material is a gel and maybe chosen from cellulose and its derivatives, alginic acid and its derivatives, sugar and sugar alcohols and glycerol. The coating material is water insoluble and comprises calcium silicate. Magnesium silicate, silicon dioxide, calcium or magnesium stearate may also be added to the coating. EP675194 discloses liquid detergent compositions comprising encapsulated particles. The detergent active is adsorbed on a porous, hydrophobic material. Hydrophobic silica can be used as the porous material. The material is further coated with a hydrophobic compound, an example of which is silicone oil. W09842 818 discloses laundry functional ingredient particles for effective perfume delivery comprising a porous carrier core intermixed with a glassy encapsulating material. The porous core is a zeolite. The encapsulating material is a glassy, partially water soluble or water dispersible compound and can be selected from water soluble polymers, carbohydrates, cellulose and waxes amongst others. WO 9748386 discloses a compressed core tablet comprising a therapeutic dose of diltiazem (the active), colloidal silica and magnesium stearate amongst others. Encapsulation methods are known in the prior art. It is also well known in the art that heat, moisture and pH sensitive functional ingredients such as potassium iodate and vitamins are lost during storage and/or cooking. The functional ingredients are therefore not available to the body during or after consumption of food articles containing them., a problem which needs to be addressed. Encapsulation methods as known in the art do not ensure that the coating is heat, moisture and pH resistant and that the encapsulated functional ingredients are made available to the body. Additionally, certain functional ingredients such as iron containing compounds and oligopepetides are known to adversely affect the organoleptic properties of foods. This can be attributed to interaction of the functional ingredients with other components present in the food. The problem has not been satisfactorily addressed by the prior art. The applicants have now shown that it is possible to provide for novel encapsulated particles comprising functional ingredients and a process to make the same. Such encapsulated particles can be suitably incorporated in foods. It is thus possible to provide for a) stability of the functional ingredients under the conditions of processing and storage of the food b) stability in the presence of reducing agents c) moisture, heat and pH resistance and d) break down of the coating of the invention in the digestive system to make functional ingredients available for bio-absorption. The encapsulated particle of the invention also isolates the functional ingredient from other components of the food thereby significantly improving organoleptic properties of the food. SUMMARY Thus the present invention provides for free flowing particles comprising an inorganic, porous core material in which a water soluble functional ingredient is impregnated and a water insoluble, heat stable outer coating which comprises one or more multivalent metal salts of fatty acids and a process to make the same. The particles prepared by this process can be incorporated in food articles. The outer coating breaks down during the digestion process to make the functional ingredient bio-available to the body. Examples of water soluble functional ingredients are iodine and iron containing compounds, carotenoids and oligopeptides. DEFINITION OF THE INVENTION According to the first aspect of the invention there is provided an encapsulated particle comprising: a) an inorganic, porous core in which one or more water soluble functional ingredients are impregnated and b) a water insoluble outer coating comprising one or more multivalent metal salts of fatty acids wherein the fatty acid has a chain length not less than 8 and the melting point of the coating is greater than 100°C. According to the second aspect of the invention, there is provided a process to make the encapsulated particles of the invention comprising the steps of a) forming the impregnated core by adding an aqueous solution of the functional ingredient to an inorganic, porous material such that the solution does not occupy more than 90% of the pore volume b) forming a coating of the multivalent metal salt of one or more fatty acids on the impregnated core According to a thrid aspect of the invention, there is provided a synergistically fortified food article comprising the encapsulated particles of the invention. DETAILED DESCRIPTION OF THE INVENTION All parts given herein below are by weight unless otherwise specified. The encapsulated particle The encapsulated particle comprises one or more functional ingredients that are dispersed in an inorganic, porous core. The porous core is preferably hydrophilic in nature. The inorganic porous core is referred to hereinafter as the porous core and the porous core comprising one or more functional ingredients is referred to hereinafter as the impregnated core. The impregnated core is further coated with one or more multivalent metal salts of fatty acids (referred to hereinafter as outer coating) . The porous core and the outer coating are preferably present in a ratio from 1:0.1 to 1:10, more preferably from 1:0.2 to 1:5 and most preferably from 1:0.2 to 1:3. It is essential that the outer coating substantially encapsulates the impregnated core. The particle size of the encapsulated particle is preferably from 0.1 to 100 micron, more preferably from 0.5 to 80 micron and most preferably from 1 to 50 micron. Process of coating or encapsulation The porous core is impregnated with one or more water soluble functional ingredients by adding an aqueous solution of the functional ingredient to the inorganic porous material. A preferable method of adding is spraying or adding the aqueous solution drop-wise to a stirred powder of the inorganic, porous material. It is preferable that the aqueous solution of the functional ingredient be added in a gradual manner to the inorganic, porous material to prevent agglomeration of the inorganic, porous material. The aqueous solution occupies not more than 90% of the pore volume of the core material. The impregnated core may be optionally dried to remove water from the pores. Water can also be removed from the pores by dispersing the impregnated core in a solvent in which water is soluble but the functional ingredient is insoluble. The impregnated core that is formed needs to be further coated with the one or more multivalent metal salts of fatty acids. The coating can be provided by several methods. A preferred method to obtain the coating is to first add the impregnated core to a mixture of a multivalent metal hydroxide, a multivalent metal halide and a suitable solvent. The fatty acid melt is then added to this mixture to generate the water insoluble, outer coating of the impregnated core. The outer coating is formed by the in-situ generation of the metal salt of fatty acid and precipitation on the impregnated core. It is essential that the pH of the mixture of the multivalent metal hydroxide, multivalent metal halide and the solvent be from 8 to 10.5. Without being limited by theory, this buffering is necessary to retain the required structure of the impregnated core. More preferably the pH is from 9 to 10.5 and most preferably from 9.9 to 10.3. Calcium and magnesium hydroxide are especially preferred multivalent metal hydroxides. Calcium and magnesium chloride are especially preferred multivalent metal halides. The multivalent metal halide is preferably present in an amount of 3 5-50% by weight of the multivalent metal hydroxide, more preferably from 39 to 42% by weight of the alkaline earth hydroxide. The solvent should have a moderate dielectric constant, should not dissolve the functional ingredient present in the impregnated core and should solubilise the fatty acid. Examples of such solvents are C1-C6 short chain alcohols. Ethanol is an especially preferred solvent. Without being limited by theory, the solvent enables dissociation of the fatty acid as well as the metal hydroxide resulting in the formation of the fatty acid salt. In a typical process, the impregnated core is added to a mixture of the multivalent metal hydroxide, a multivalent metal halide, solvent and stirred. This dispersion is then added to the fatty acid melt. The fatty acid melt comprises one or more fatty acids. It is required that the mixture be continuously stirred. The temperature of the reaction mixture is from 60-75°C, more preferably from 65-75°C. The mixing time is not critical, preferably the time is at least 10 minutes. In-situ precipitation of the fatty acid salt or fatty acid salts takes place on the impregnated core to give substantially encapsulated particles. The solvent can be removed by any conventional process of drying or evaporation and can be recycled. It is known in the art that complete encapsulation does not take place. The process of the invention thus provides for substantial encapsulation of the porous core. Functional ingredients The amount of the functional ingredient in the porous core is preferably from 0.1 to 60%, more preferably from 1 to 30% and most preferably from 5 to 20%. The functional ingredient is present in the pores of the inorganic, porous material. When the functional ingredient is an iodine containing compound, it is preferably chosen from alkali metal iodides or iodates or their mixtures thereof. Iron compounds suitable for encapsulation include ferrous sulphate, ferrous gluconate and ferrous fumarate as well as iron-amino acid complexes like ferrous sulphate-glycine. Vitamin C or its precursors, carotenoids and oligopeptides are also suitable water soluble functional ingredients that can be encapsulated by the process of the invention. Peptides containing fewer than 10 amino acids are called oligopeptides. The porous core The porous core is inorganic, water insoluble and hydrophilic in nature. The porous core is chosen such that its average pore diameter is greater than that of the hydrated sphere of the functional ingredient or its dissociated ion. The pore volume is large enough to contain the aqueous solution of functional ingredients. The porous core is preferably chosen from one or more of silica, silicates and alumino-silicates. Silica is preferably present in the form of amorphous silica. Silicates include the alkali metal and alkaline earth metal silicates. Alumino-silicates include zeolites. Amorphous silica is an especially preferred core material. The particle size of the porous core is preferably from 0.1 to 50 micron, more preferably from 0.2 to 25 micron, and most preferably from 0.5 to 10 micron. The pore diameter of the porous core is preferably from 0.1 to 500 nm, more preferably from 0.4-100 nm and most preferably from 0.5-50 nm. The pore volume of the porous core is preferably from 2 to 5.5 ml/g, more preferably from 2.5 to 2.8 ml/g. The outer coating The outer coating is hydrophobic, water insoluble and has a melting point greater than 100°C. The outer coating preferably comprises one or more multivalent metal salts of a fatty acid of chain length not less than 8. More preferably, the outer coating is the multivalent metal salt of one or more of stearic, palmitic and myristic acid and most preferably the outer coating is the calcium salt of stearic acid. When a mixture of fatty acids is used, they can be used in any ratio without affecting the stability and the water insoluble nature of the outer layer, provided the melting point of the outer coating is greater than 100°C. The thickness of the outer layer is preferably from 0.003 micron to 1 micron, more preferably from 0.01 micron to 0.8 micron, and most preferably from 0.1 to 0.5 micronµ,. The outer coating is stable at pH of 4.0 and above. The pH in the stomach may vary from 0.9 to 3.0. The coating will break down during the digestive process and the functional ingredient will be released from the porous core. Incorporation of the encapsulated particle in a food article The encapsulated particle of the invention can be added to food articles. Examples of such food articles are salt, beverages, wheat flour, fruit juices, cereals etc. The invention is further illustrated by the following non-limiting Examples, in which parts and percentages are by weight unless otherwise specified. EXAMPLES Comparative Example A 18 ml of an aqueous solution of potassium iodate (E. Merck (I) Ltd.) was added slowly to 10 g of dry precipitated silica (ex Madhu Silica Pvt. Ltd., India) at 25°C with continuous stirring for 30 minutes. The impregnated core was recovered as a dry powder at the end of this process. The average particle diameter was determined by Zeiss microscope and was found to be 4-15 micron. The total iodate content was determined by iodometry and was found to be 8% (with respect to silica). Comparative Example B 8 g of potassium iodate was added to a mixture of molten stearic and palmitic acid (ex Loba Chemie, Mumbai, India). The ratio of the stearic acid: palmitic acid was 55:45. The molten fatty acid was maintained at 75 °C. The mixture was stirred and subsequently cooled down to laboratory temperature. The average particle diameter as determined by Zeiss Microscope was found to be 50-200 micron and the total iodate content was 8% (with respect to calcium stearate) as determined by iodomtery. Example 1 Process for preparing the encapsulated particle a. Method of preparing the impregnated core 18 ml of an aqueous solution of potassium iodate (E. Merck (I) Ltd. ) was added slowly over a period of 30 minutes to 8 g of dry precipitated silica (ex Madhu Silica Pvt. Ltd., India) at 25°C. The mixture was continuously stirred during the addition. The impregnated core was recovered as a dry powder at the end of this process. b. Method for preparing the encapsulated particle 2.15 g. of calcium chloride was added to ethanol to form a homogeneous solution. This solution was further added to an ethanolic dispersion of calcium hydroxide. The pH of the stirred mixture was 10.3. The KIO3 containing impregnated core was added to the ethanolic dispersion. There was no significant change in pH. The ethanolic dispersion comprising the impregnated core was poured into 24 g of molten stearic and palmitic acid (ex Loba Chemie, Mumbai, India). The ratio of the stearic acid: palmitic acid was 55:45. The mixture was maintained at 7 5 °C and continuously stirred. It was subsequently cooled down to laboratory temperature. The excess ethanol was removed by filtration. The encapsulated particle was obtained as a free flowing powder with an average particle diameter is 5 micron. The total iodate content was 3.3% in the encapsulated particle. Stability in water (room temperature and boiling temperature) The stability of the encapsulated particle in water and its ability to retain the iodate was determined. In the first test, the material of Example 1 was stirred in water for 3 0 minutes. The dispersion was then filtered and the amount of potassium iodate in the filtrate was determined by iodometry. The procedure was repeated for Comparative Examples A and B. In the second test, the material of Example 1 was dispersed in water and the temperature of the water was raised to boiling temperature. The boiling was continued for 3 0 minutes. The dispersion was then filtered and the amount of potassium iodate in the filtrate was determined by iodometry. The procedure was repeated for Comparative Examples A and B. The potassium iodate retained in the particle is expressed as follows: % iodate retained by the particle = (Itotai _ If literate) / Itotai X 100 where Itotai is the total iodate content in the particle and Ifnterate is the iodate content in the water (after filteration). The results are shown in Table 1. Table 1 : Potassium iodate retention Example % iodate retained in the particle Water (Room Temperature) Water (Boiling temperature) A 0 0 B 25 20 Example 1 89 89 The data in Table 1 shows that most of the iodate is retained by using the encapsulated particle of the invention. Acid Stability The stability of the particle was determined under cooking pH conditions as well as in stomach pH conditions. For determining stability in cooking pH conditions, the material of Example 1 was dispersed in water and the pH of the dispersion was adjusted to 4.2. The dispersion was then boiled for 30 minutes. The dispersion was then cooled, filtered and the potassium iodate content of the filtrate was determined by iodometry. The procedure was repeated for Comparative Example A and Comparative Example B. For determining stability in stomach pH conditions, the material of Example 1 was dispersed in a 0.33 N solution of hydrochloric acid and the mixture was stirred for 30 minutes. The dispersion was filtered and the potassium iodate content of the filtrate determined by iodometry. The procedure was repeated for Comparative Example A and Comparative Example B. % iodate in the particle after the treatment was determined as explained earlier. The data are shown in Table 2 Table 2: Stability in acidic solutions Example % iodate retained in the particle Cooking pH Stomach pH A 0 0 B 15 0 Example 1 75 1.5 The data shows that the encapsulated particle of the invention is stable at cooking pH but breaks down, liberating the iodate, at stomach pH. Thus the encapsulated particle of the invention is stable under normal cooking conditions and loss or breakdown of the iodate is prevented. However, it breaks down in stomach pH conditions and can thus make the iodate bio-available for absorption by the body. The present invention thus provides for a process to make stable, encapsulated particles that break down only at a low pH. Functional ingredients that are unstable during storage and use'or those that interact unfavourably with other food components can be suitable encapsulated using the process of the invention. We claim: 1. A process for producing substantially encapsulated food additive particle comprising: a) an inorganic, porous core in which at least one water soluble functional ingredients is impregnated and b) a water insoluble outer coating comprising at least one multivalent metal salt of fatty acids wherein the fatty acid has a chain length not less than 8 and the melting point of the coating is greater than 100°C. said process comprising the steps of: a) forming the impregnated core by adding up to 90% of the pore volume of the inorganic porous material an aqueous solution of the water soluble functional ingredient; b) forming a coating of the multivalent metal salt of at least one fatty acid on the impregnated core. such that the encapsulated food additive particle thus formed has the pore volume of the porous core is from 2 to 5.5 ml/g, more preferably from 2.5 to 2.8 ml/g 2 . A process as claimed in claim 1 wherein the components a) and b) are provided in the ratio 1:0.1 to 1:10, more preferably in the ratio 1:0.2 to 1:5 and most preferably in the ratio 1:0.2 to 1:3 to form the encapsulated food additive particle. 3 . A process as claimed in claims 1 or 2 adapted to form encapsulated food additive particle having a particle size of from 0.1 to 100 micron, more preferably from 0.5 to 80 micron and most preferably from 1 to 50 micron. 4 . A process as claimed in anyone of claims 1 to 3 adapted to form encapsulated food additive particles having the particle size of the porous core is from 0.1 to 50 micron, more preferably from 0.2 to 25 micron, and most preferably from 0.5 to 10 micron. 5 . A process as claimed in claim 4 adapted to form encapsulated food additive particles having the pore diameter of the porous core is from 0.1 to 500 nm, more preferably from 0.4-100 nm and most preferably from 0.5-50 nm. 6 . A process as claimed in anyone of claims 1 to 5 adapted to form encapsulated food additive particles having the thickness of the outer layer is from 0.003 micron to 1 micron, more preferably from 0.01 micron to 0.8 micron, and most preferably from 0.1 to 0.5 micron. 7. A process as claimed in anyone of claims 1 to 6 adapted to form encapsulated food additive particles having the porous core chosen from silica, silicates and aluminosilicates. 8 . A process as claimed in claim 7 adapted to form encapsulated food additive particles having the porous core as silica, more preferably amorphous silica. 9 . A process as claimed in claim 1 adapted to form encapsulated food additive particles having the outer coating comprising at least one multivalent metal salt of a fatty acid of chain length not less than 8. 10 . A process as claimed in claim 9adapted to form encapsulated food additive particles having the outer coating material selected from calcium, magnesium salts of stearic, palmitic and myristic acid. 11. A process as claimed in claim 10 adapted to form encapsulated food additive particles having the outer coating comprising the calcium salt of stearic acid. 12 . A process as claimed in claim 1 adapted to form encapsulated food additive particles having the amount of water soluble functional ingredient from 0.1 to 60% of the porous core, more preferably from 1 to 30% and most preferably from 5 to 20%. 13 .A process as claimed in anyone of claims 1 to 12 adapted to form encapsulated food additive particles having the water soluble functional ingredient chosen from an iodine containing compound, an iron containing compound, vitamin C, precursors of vitamin C, caratenoids and oligopeptides. 14 .A process as claimed in claim 13 wherein the encapsulated food additive particles having the water soluble functional ingredient as potassium iodate or potassium iodide. 15 A process as claimed in anyone of claims 1 to 14 wherein the impregnated core is dried prior to forming said coating of multivalent metal salt on the same. 16 A process as claimed in anyone of claims 1 to 15 wherein the outer coating is obtained by adding the impregnated core to a mixture of a multivalent metal hydroxide, a multivalent metal halide and a solvent followed by addition of the fatty acid melt and removing the solvent after formation of the outer coating. 17 . A process as claimed in anyone of claims 1 to 16 wherein the pH of the mixture of multivalent metal hydroxide, a multivalent metal halide and a solvent is maintained from 8 to 10.5, more preferably from 9 to 10.5, most preferably from 9.9 to 10.3 18 .A process as claimed in anyone of claims 1 to 17, wherein the multivalent metal hydroxide used is calcium or magnesium hydroxide and the multivalent metal halide used is calcium or magnesium chloride. 19 .A process as claimed in anyone of claims 1 to 18, wherein the multivalent metal halide is used in an amount of from 35 to 50% of the metal hydroxide. 20 . A process as claimed in claim 19, wherein the multivalent metal halide is used in an amount of from 39 to 42% of the metal hydroxide. 21. A process as claimed in anyone of claims 1 to 20, wherein the solvent used is a C1-C6 short chain alcohol, preferably ethanol. 2 2 . A process as claimed in anyone of claims 1 to 21 wherein the said coating of the multivalent metal salt of atleast one fatty acid on the impregnated core is formed by in-situ generation of the metal salt of fatty acid and precipitating on the impregnated core. 2 3 . A process for forming synergistically fortified food article comprising providing the substantially encapsulated food additive as formed by the process of claims 1 to 22. 2 4 .A process for forming synergistically fortified food article as claimed in claim 23, comprising providing substantially encapsulated common salt wherein the water soluble functional ingredient is potassium iodate or potassium iodide.

Documents:

310-mum-2001-cancelled pages (23-09-2004).pdf

310-mum-2001-claims (granted) (23-09-2004).doc

310-mum-2001-claims (granted) (23-09-2004).pdf

310-mum-2001-correspondence (ipo) (13-09-2004).pdf

310-mum-2001-correspondence 1(02-04-2002).pdf

310-mum-2001-correspondence 2(06-04-2005).pdf

310-mum-2001-form 1(03-04-2001).pdf

310-mum-2001-form 19(23-06-2003).pdf

310-mum-2001-form 2 (granted) (23-09-2004).doc

310-mum-2001-form 2(granted) (23-09-2004).pdf

310-mum-2001-form 3(02-04-2002).pdf

310-mum-2001-form 5(02-04-2005).pdf

310-mum-2001-form-pct-ipea-409 (02-04-2002).pdf

310-mum-2001-form-pct-isa-210 (22-10-2003).pdf

310-mum-2001-other (17-06-2002).pdf

310-mum-2001-petition under rule-138(23-01-2004).pdf

310-mum-2001-power of attorney (17-06-2002).pdf