Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF STABLE RED BEET PIGMENT CONCENTRATE

Abstract

The present invention particularly relates to a process of treating beet root/ beet hairy roots to recover red betacyanin pigments in the form of a liquid concentrate with extended fade resistance and shelf life. The present invention enables to obtain betacyanin in liquid form. The extraction procedure of the present invention enables to maximize the betacyanin recovery in contrast to the prior art. Further the presence of polyols, which are GRAS substances in the final product, was observed to enhance the solubility and thermal stability on storage of betacyanin.

Full Text

The present invention relates to an improved process for the preparation of stable red beet pigment concentrate. The present invention particularly relates to a process of treating beet root/ mta beet hairy roots to recover red b cyanin pigments in the form of a liquid concentrate with extended fade resistance and shelf life. Betacyanin pigments are suitable for the use in yogurt, sherbet, ice creams, frozen fruit desserts, candies, frostings and puddings (Freund et al 1988, Natural colour for use in foods, Cereal Foods World 33: 553-559). In recent years the use of natural colorants has been steadily increasing because of the changes in consumer preference towards more natural products, which is known to exhibit specific functional properties. However natural colorants are more sensitive to heat, light and pH than their synthetic counterparts. Therefore they are usually added at the lowest possible temperature and as late as possible during processing. Developments in natural colors therefore tend to focus on evaluating unexploited food sources of permitted pigments and on improving the stability, dispersibility and handling properties. The red table beet (Beta vulgaris L.) is a rich source of red pigments termed betacyanins. Together with a small amount of yellow pigments, namely betaxanthines, these pigments comprise of a class of compounds called betalaines (Pasch, JH et al. (1975), Betalaines as colorants in Dairy Products, J. Milk Food Technol, 38, 25-28). Of the betacyanines, betaine is the principle component, accounting for 75% to 95% of the total betacyanine content of the beet (von Elbe et al, 1972, Quantitative analysis of betacyanins in red table beets (Beta vulgaris), J. Food Sci, 37: 932-934). Commercial preparation of beetroot can be either in the form of liquid concentrates or dehydrated beet powders. Liquid concentrates are prepared by pressing blanched ground beets, filtering the liquid and concentrating under vacuum to 60- 65% solids. The above mentioned beet juice is usually spray dried with maltodextrin and is called beet powder. Dehydrated beet powder is generally used in dry mix products in which the brown notes and insolubles are not an issue. Commercial beet powders usually contain 0.4 to 1 % pigment expressed betanin, 80% sugar, and 8%ash and 10% protein together with citric acid/ascorbic acid as a preservative. The stability of betacyanins from red beet is strongly affected by pH, temperature, oxygen, light, and water activity. The influence of temperature on the stability of betacyanin is very significant (von Elbe et al 1974, J. Food Science 39:334). The half-life of the heat decomposition of betacyanin depends on the pH value, although generally decreases with increase in temperature. Elbe et al (1981) reported the pigment losses during betacyanin processing which suggests that there will be a total pigment loss of 41% during canning. Blanching to an initial temperature of 66°C causes 63% loss where as sterilization at 126°C for 10 min accounts for a loss of 22%. The stability of betacyanin is also strongly influenced by the presence of oxygen. When oxygen is depleted from the concentrates the stability increases significantly (Adams and von Elbe, 1977, J. Food science 42:410). Another important factor which influences the stability is the water activity and the decomposition of the pigments is reduced at lower values of water activity (Pasch JH and von Elbe JH, 1975, J Food Science: 40:1145). Visible and ultraviolet radiations as well as the presence of heavy metal ions have negative effects on betacyanin stability (Havilikova et al 1983, Heat stability of Betacyanins, Z.Lebensm Unters Forsch, 177: 247-250). Commercial beet colorants vary considerably in colour strength, depending on their content of yellow betaxanthines. The betaxanthine content varies depending on the colour varieties of beet variety, beet root quality and maturity at harvest, method of pigment extraction. Beet root pigment is typically used as a colorant of 4-25 mg/kg in quite a wide range of dairy and confectionery products as well as meat substitutes (Serris GS and Billiaderis 2001, Degradation kinetics of beet root pigment encapsulated in polymeric matrices, Journal of the Science Food and Agriculture 81: 691-700). Production of betacyanin concentrate and powder has been studied for many years and there are many research articles and patents concerning it. Reference may be given to Elbe et al 1974 (von Elbe JH, Adams JP, and Pasch JH (1974) Betalaines as food colorants, IV- international congress of food science and technology 1d, 18-20) wherein the large scale purification methods involving fermentation of carbohydrates in beet juice followed by concentration and/or purification on polyvinyl-pyrrolidone columns to produce dry preparations with 50-75% pigment content. The possible drawback of the above mentioned method may be, even though several resins and other absorption processes such as Dowex SOW followed by polyamide column chromatography and numerous others are available for purification of pigments, they are not permitted by law (Francis FJ, In Colorants 1999, Eds) Reference may be made to the process for the production of beet powder by Kopelman and Saguy (1977) wherein drum drying is used for the production of beet powder. Reference may also be made to the method of Vorovski (1984) where in the method is based on hot steam treatment of raw beet roots, concentration of the resulting juice and drying the mash to get beet powder. The possible draw back of the above mentioned methods can be the loss of pigments during heating and further it will result in the production of whole beet powder rather than a concentrate. Therefore a large amount of beet powder may be needed to get the required colour in the product and the use is limited to dry mixed powders only where the brown notes and insolubles are not an issue. Reference may be made to the method of Driver and Francis (1979), where in the extraction of the pigment was carried out using solvents like butanol, acetone and diethyl ether. The possible draw back in the above method can be the solvents used are not of food grade and the concentrate of beet colour prepared from this has to be again stabilized as in the pure form will be highly hygroscopic and the presence of moisture content will affect severely the stability. Reference may be made to the US patent (US4132793: Stable beet colour composition) where in the natural dye stuff from beet root is stabilized using antioxidants like ascorbic acid and phosphates like sodium hexametaphosphates and EDTA. The draw back of the above mentioned method is that this refers to the in situ stabilization and it has been beet powder preparation only. Reference may be made to the US patent (US 4027042: Colour extract from beets and method of preparation for the same) wherein the preparation of the colouring agent by fermenting the beet pigment, separating the soluble phase from the insoluble phase and then removing the aqueous medium to produce beet concentrate. The draw back of the above said method is that, it describes the removal of sugars by fermentation, which at times can produce off flavours in the product, and also the additional step of fermentation is cumbersome. Reference may be made to the method of Adams (1978) wherein the pigment is extracted and the juice is subjected to ultra filtration and then subjected to fermentation by Candida utilis, under partially anaerobic conditions and then dried to get a dry powder. The possible drawback of the above mentioned method can be that it results in a concentrated liquid containing water which may severely affect the stability during storage. Reference may be given to the US patent 4371549 where in a stable liquid red beet colour is provided which is formed by spray drying liquid beet colour carried on a solid medium such as gum arable or maltodextrin, which is dispersed in a liquid medium such as glycerin, hydrogenated vegetable oil or propylene glycol. The possible drawback in the above-mentioned patent can be that there will be a loss of betacyanin during the spray drying process, as betacyanin pigments are not heat stable. Reference may be made to C.F.T.R.I process (Annual report of C.F.T.R.I, 1987: Natural Food colours) where in, 1. Colour is extracted from beet root, Ph. is brought down and concentrated. 2. Colour is extracted, fermented using yeast and than concentrated. 3. The above-obtained concentrate is spray dried with maltodextrin. The drawback of above said method is that, the concentrate contains water that may affect the stability, also additional step of fermentation is cumbersome, and colour obtained in powder form will be very hygroscopic. The main object of the present invention is to provide an improved process for the preparation of a stable red beet pigment concentrate, which obviates the drawbacks as detailed above. Another object of the present invention is to maximize the yield of pigments from beet rood/beet hairy root. Yet another object of the present invention is to provide a betacyanin extraction and stabilization method, which is fast, effective, uses simple and inexpensive chemicals. Still another object of the present invention is to provide a stabilization method, which enhances the light and heat stability of the pigment. In another object of the present invention is to include the stabilization agents in the extraction solvent. Accordingly the present invention provides an improved process for the preparation of stable red beet pigment concentrate, which comprises: a) granting mechanically the red beet by using a pulper, b) adding ethanol containing organic acid as herein described in the range of 0-0.01% (v/v), polyols in the range of 2-10% (v/v) and a chelating agent ethylenediamine tetraacetic acid (EDTA) in the range of 0.001-0005 g/1 to the above said pulp obtained in step (a) in a pulp to solvent ratio in the range of 1:1 to 1:2.5 (w/v), c) stirring the above said reaction mixture at a temperature in the range of 20-3 0°C for a period of 0.5-1.5 hr, d) filtering the above said mixture to separate the liquid phase and the residue, e) repeating the above steps twice to obtain residue and pooling the corresponding filtrates and f) clarifying the filtrates as obtained in step e) by passing through diatomaceous earth, followed by concentration under vacuum to obtain solvent free red beet pigment concentrate. In An embodiment of the present invention, the organic acid used may be selected from acetic acid and citric acid. In another embodiment of the present invention, the polyol used may be selected from glycerol, propylene glycol and a mixture thereof. Yet in another embodiment of the present invention, the chelating agent used may be selected as ethylenediamine tetraacetic acid (EDTA) The novelty of the present invention lies in the extraction and stabilization method in which the betalaines are allowed to selectively diffuse in to the extraction medium containing the stabilizing agents and getting a very stable betalaine concentrate which has high dispersibility and storage stability. The present invention enables to obtain betacyanin in liquid form. The extraction procedure of the present invention enables to maximize the betacyanin recovery in contrast to the prior art. Further the presence of polyols, which are GRAS substances in the final product, was observed to enhance the solubility and thermal stability on storage of betacyanin. The present invention comprises of the following steps 1. Preparation of the whole beet pulp by means of grating, homogenizer or pulper. 2. Contacting the beet root pulp with ethanol containing acetic acid or citric acid in the range of 0- 0.01%, glycerol (in the range of 2-10% )or propylene glycol (in the range of 2-10% )or a mixture of glycerol and propylene glycol (in the range of 2-10%) , where in glycerol/propylene glycol ratio is in the range of 2:8 to 8:2v/v) by volume of the extraction solvent, EDTA (in the range of 0.001 to 0.005 gm), and allowing the betacyanin to diffuse into the extraction medium for a period of 1 to 4 hours at ambient temperature. 3. Separation of the liquid phase from the beet pulp by means of filtration 4. Repeating the extraction of this beet pulp was carried out twice or thrice as described in step 2 5. Clarification of the filtrate through diatomaceous earth to obtain clear betacyanin solution. 6. Concentration of the betacyanin solution to get betacyanin concentrate stabilized in glycerol or propylene glycol or in glycerol/propylene glycol mixture. The following examples are given by the way of illustration of the present invention and therefore should not be considered to limit the scope of invention. Example 1 Five hundred grams of beet root were washed thoroughly, grated in pulper and 1 liter of extraction solvent (ethanol) containing 1ml of citric acid, 20m! of propylene glycol, and 0.002gm of EDTA was added, mixed well using a stirrer and allowed to stand for 1 hour at ambient temperature. The extraction solvent containing betacyanin was then recovered by filtration. The extraction was repeated twice in the same way and all the extracts were combined and passed through diatomaceous earth. The filtrate was concentrated using vacuum to get betacyanin concentrate. The betacyanin concentrate thus obtained was highly stable and can be stored at room temperature. However the concentration of the beet pigment in the concentrate prepared in accordance with the practice of this invention can vary depending mainly on the variety of beet that is used for the extraction. Concentrated volume of 50ml having 2.7 gms of betalaine was obtained with a recovery of 90%. Example 2 Five hundred grams of beet root were washed thoroughly, grated in pulper and 1 liter of extraction solvent (ethanol) containing 1ml of acetic acid, 20ml of glycerol, and 0.002gm of EDTA was added, mixed well using a stirrer and allowed to stand for 1 hour at ambient temperature. The extraction solvent containing betacyanin was then recovered by filtration. The extraction was repeated twice in the same way and all the extracts were combined and passed through diatomaceous earth. The filtrate was concentrated using vacuum to get betacyanin concentrate. The betacyanin concentrate thus obtained was highly stable and can be stored at room temperature. However the concentration of the beet pigment in the concentrate prepared in accordance with the practice of this invention can vary depending mainly on the variety of beet that is used for the extraction. Example 3 Five hundred grams of beet root were washed thoroughly, grated in pulper and 1 liter of extraction solvent (ethanol) containing 1ml of citric acid, 10ml of propylene glycol, 10ml of glycerol and 0.002gm of EDTA was added, mixed well using a stirrer and allowed to stand for 1 hour at ambient temperature. The extraction solvent containing betacyanin was then recovered by filtration. The extraction was repeated twice in the same way and all the extracts were combined and passed through diatomaceous earth. The filtrate was concentrated using vacuum to get betacyanin concentrate. The betacyanin concentrate thus obtained was highly stable and can be stored at room temperature. However the concentration of the beet pigment in the concentrate prepared in accordance with the practice of this invention can vary depending mainly on the variety of beet that is used for the extraction. The main advantages of the present invention are 1. The extraction can be carried out with out the use-sophisticated equipment and easy to scale up. 2. The extraction method helps not only in maximizing the yield of betacyanin pigment but also in enhancing the thermal stability of the product. 3. Since the extraction solvent (ethanol) can be completely removed during concentration process and can be reused. 4. The process is environment friendly due to the use of biocompatible and GRAS (generally regarded as safe) substances. 5. The concentrate is easily dispersible in water, and also has improved stability to neat, light and oxidation. 6. The concentrate is not hygroscopic We claim: 1. An improved process for the preparation of stable red beet pigment concentrate, which comprises: a) granting mechanically the red beet by using a pulper, b) adding ethanol containing organic acid as herein described in the range of 0-0.01% (v/v), polyols in the range of 2-10% (v/v) and a chelating agent ethylenediamine tetraacetic acid (EDTA) in the range of 0.001-0005 g/1 to the above said pulp obtained in step (a) in a pulp to solvent ratio in the range of 1:1 to 1:2.5 (w/v), c) stirring the above said reaction mixture at a temperature in the range of20-30°Cfora period of 0.5-1.5 hr, d) filtering the above said mixture to separate the liquid phase and the residue, e) repeating the above steps twice to obtain residue and pooling the corresponding filtrates and f) clarifying the filtrates as obtained in step e) by passing through diatomaceous earth, followed by concentration under vacuum to obtain solvent free red beet pigment concentrate. 2. A process as claimed in claim 1, where in the organic acid used is selected from acetic acid and citric acid. 3. A process as claimed in claims 1&2, wherein the polyol used is selected from glycerol, propylene glycol and a mixture thereof. 4. An improved process for the preparation of stable red beet pigment concentrate substantially as herein described with reference to the examples.

Documents:

360-DEL-2002-Abstract-(21-04-2009).pdf

360-del-2002-abstract.pdf

360-DEL-2002-Claims-(21-04-2009).pdf

360-del-2002-claims.pdf

360-DEL-2002-Correspondence-Others-(21-04-2009).pdf

360-del-2002-correspondence-others.pdf

360-del-2002-correspondence-po.pdf

360-DEL-2002-Description (Complete)-(21-04-2009).pdf

360-del-2002-description (complete).pdf

360-del-2002-form-1.pdf

360-del-2002-form-18.pdf

360-del-2002-form-2.pdf

360-DEL-2002-Form-3-(21-04-2009).pdf

360-del-2002-form-3.pdf