STABLE WATER-IN-OIL EMULSIONS

Abstract: The present invention describes stable water-in-oil emulsions comprising the following components: water, oil, a labile compound of interest, a stabilizing agent and an emulsifier. The labile compound present in the water phase is stabilized by addition of a stabilizing agent which preferably is a polyol. Specific emulsifiers are described which give rise to stable emulsions in the presence of high amounts of a polyol.

Description: Stable water-in-oil emulsions Technical field The present invention describes stable water-in-o emulsions. The emulsions are used to add labile compounds feed, food or cosmetic compositions. Background of the invention Several additives for food, feed and cosmetics a regarded labile, such as colourants, vitamins, vaccines enzymes. Additives can be chemically or enzymatical incompatible with other compounds present in a compositio Otherwise, additives can be heat labile and therefore tend be deactivated during processing steps which occur at elevated temperature. For example, feed or food is oft prepared by using an extrusion process. These extrusi processes are necessary for obtaining food or feed particl in the required shape. Furthermore, there is a growi tendency to include all sorts of additives to a basic feed food. Feed or food compositions are more often prepared co plete with additives which previously used to be add independently. Several solutions have been suggested to overco degradation of a labile compound. One solution is t addition of the desired compounds subsequent to a proce step at elevated temperature, e.g. after the extrusi process. Different reports have been published concerni formulations of labile compounds and/or for methods to a such compounds to feed or food particles. DE 2602260 describes the use of a suspension of enzyme in a liquid or a molten edible fat. After cooling the mixture the material has to be particularized. Aft rough destruction the particles are further treated f example by milling. This process has the disadvantage tha the milling of powders to guarantee a small particle size i very tedious and leads to undesirable dusts. International Patent Application WO 93/14645 solves th problem by addition of an oil suspension containing the heat labile compounds after the extrusion process. The addition o the suspension to the pellets is performed under lowere pressure. International Patent Application WO 92/06599 describe the use of a water-in-oil emulsion for protecting vaccines There is no mentioning of the use of a (protein) stabilizin (i.e. a water activity lowering) agent as part of th emulsion. The formulation of labile compounds such as enzyme in such an emulsion would give rise to a rapid loss of enzym activity. This loss may amount to 50% per month in ho climates which is unacceptable for commercial products. Thi patent application also describes the preferred applicatio of a lecithin-based emulsifier. International Patent Application WO 93/16175 describes stabilized, aqueous enzyme solution comprising urea and/or polyol as stabilizing agent. Urea and polyols are know agents to stabilize an enzyme in an aqueous environment. In the area of cosmetics there also is a growin tendency to include labile compounds in oil containing en products. Especially compounds aimed at skin protection cleansing and rejuvenation are of obvious interest. Labil compounds claimed to have beneficial effects in this respec include enzymes, such as proteases. To guarantee enzyme activity in cosmetic formulation over extended shelf life periods, essentially water-free hydrophobic compounds such as waxes, plant or mineral oil commonly are used as enzyme formulation agents. Although thi approach implies a high storage stability of the enzyme i the cosmetic formulation, a serious disadvantage is that th enzyme can only be activated by exposing the formulations t relatively large quantities of water (during which th initially water-free enzyme, is dissolved) . An inheren problem is that enzyme activation is relatively slow and th much of the initial enzyme activity is wasted. This approa is not very convenient in several cosmetic applications. In an alternative approach as described in J0300479 protein decomposing enzymes to be used in cosmetics a stabilized by adding polysaccharides to aqueous solution the enzymes. Although this approach minimises the use water needed to re-activate the enzyme, the approa disregards the need for a lipophilic phase in many cosmet formulations. Summary of the invention The present invention discloses stable water-in-o emulsions. Specifically, the present invention discloses water-in-oil emulsion characterized in that it comprises t following components: water, oil, a labile compound interest, a stabilizing agent and an emulsifier. The water-in-oil emulsions of the present inventi comprise a labile compound of interest dissolved in the wat phase and stabilized by addition of a stabilizing agen Preferably, the stabilizing agent is a water activi lowering agent. More preferably, the stabilizing agent is polyol. The polyol is added to the water phase of the water-i oil emulsion in high concentrations, i.e. in amounts of least 10%, preferably in amounts of 10-70%, more preferab in amounts of 30-70% (w/w) . A preferred composition comprises a water-in-o emulsion containing a labile compound of interest in t water phase together with a polyol, and wherein the emulsi is stabilized using an emulsifier which is active at hi concentrations of the polyol. The emulsifier which is us preferably is a distilled monoglyceride or polyglycer polyricineolate. Furthermore, the compound of interest preferably is enzyme, a vitamin, a colourant or a vaccine. The presented emulsions are used to protect labil compounds before addition to food, feed, cosmetic or oil compositions. The water-in-oil emulsions of the present invention ar stable for prolonged periods of time. They can be used fo the preparation of human or animal food compositions. Fo instance, the water-in-oil emulsions of the present inventio are sprayed on feed or food particles. Preferably, th emulsions are sprayed on feed or food particles afte dilution of the emulsion in an oil or fat. In addition, th emulsions of the present invention can be used for th preparation of cosmetic compositions. Detailed description of the invention The present invention discloses a water-in-oil emulsio containing in the water phase a compound of interest which i labile together with a stabilizing agent, and wherein th emulsion is stabilized using a suitable emulsifier. The water-in-oil emulsion comprises the followin components: water, oil, a labile compound of interest, stabilizing agent and an emulsifier. The labile compounds ar present in the water phase. The stabilizing agent is added t the water phase to stabilize the desired compound. The labile compound can be any compound which i chemically or enzymatically incompatible with othe compounds. An incompatible compound can be present either i the emulsion or in the composition to which the emulsion i added. In addition, the labile compound can be any compoun which is heat labile. The present invention discloses stable water-in-oi emulsions comprising more than one labile compound in th water phase. The present invention also discloses stabl water-in-oil emulsions comprising a labile compound and compound incompatible with the labile compound in the wate phase. The present invention enables the preparation emulsions comprising mutually incompatible, water-solub compounds. The physical separation of these incompatib compounds is advantageously accomplished by the incorporation in individual water droplets in the oil pha of the emulsion. Preferably, the labile compound comprises li microorganisms, which can be used for instance as probiotic. More preferably, the labile compound is an enzym a vitamin, a colourant or a vaccine. Suitable enzymes inclu proteases, phytases, carbohydrases, lipases, phospholipas and oxidoreductases. Suitable vitamins include water-solub vitamins, e.g. vitamin C. The emulsions of the present invention are especial useful to formulate mutually incompatible compounds, e. enzyme mixtures of which one of the enzymes is a proteolyt enzyme. Furthermore, the emulsions of the present inventi enable an exact dosage of labile compounds. First of a because stability of the labile compounds is guarantee additionally because dosage of a liquid emulsion, particular of an emulsion diluted in oil, is more preci than dosage of a powder. For instance, it is known th during the processing of feed, factors like heat, pressur humidity, redox reactions and friction can have a dramat impact on the stability of vitamins. Especially vitamins E, and C (ascorbic acid) are known for their instability (s for example M.B. Coelho, Feed International, December 199 page 39-45) . Ascorbic acid is water soluble and known to extremely sensitive to trace minerals which are common added to feed, such as iron. The incorporation of ascorb acid into the water phase of a water-in-oil emulsi according to the present invention is an attractive option minimise costly overdosage of the vitamin. The water-in-oil emulsions of the present inventi contain a water phase containing the desired compound in highly concentrated form. The desired compound can be add to the water phase in an amount of 0.01-30% (w/w) on basis the dry weight of the active compound. The labile compounds are stabilized by the addition of stabilizing agent to the water phase. Preferably, a wat activity lowering agent is used as a stabilizing agent. T water activity lowering agent preferably is a salt, mo preferably a polyol. Polyols that are particularly useful a glycerol, sorbitol, sucrose, polypropylene glycol, trehalos maltodextrins, lactose and glucose. In addition, the water activity lowering agent will a to prevent microbial growth in the water phase of t emulsion. If required, the microbial stability of the wat phase can be further enhanced by incorporation of general accepted (foodgrade) antimicrobial agents, such as sorbat or benzoates. The amount of a water activity lowering agent to added to the water phase depends on the amount of the age which is required to obtain the desired stabilizing or t desired antimicrobial effect. Polyols are added to the wat phase in amounts of at least 10%, preferably in amounts 10-70%, more preferably in amounts of 30-70% (w/w). To obtain stable emulsions, an emulsifier is use Emulsifiers are surface-active substances which allow o liquid phase to be dispersed in another liquid phas Emulsifiers possess both hydrophilic and lipophilic group the ratio of these groups is known as the HLB value. In general, fat-soluble, hydrophobic emulsifiers ha HLB values in the range of 0-9, while water-solub substances have HLB values between 11 and 20. Suitab emulsifiers or mixtures of emulsifiers for stabilizing wate in-oil emulsions are claimed to have HLB values in the low range. Surprisingly, well known emulsifiers such as Span™ 8 (HLB=4.3) , Tween™ 80 (HLB=15) and mixtures thereof do n give rise to stable water-in-oil emulsions in the presence relatively high amounts of polyols. Lecithin-bas emulsifiers, like Emulbesto™ 2000, Emulfluid™ E likewi result in fast phase separation. The present invention for the first time describe emulsifiers which are active in the presence of relativel high amounts of polyols. Emulsifiers which work in th presence of amounts of polyols as high as 50% have bee found. Useful emulsifiers are monoglycerides (such as Hymono 1163 and Hymono™ 7804) and polyglycerol polyricinoleat (Admul™ WOL 1403) . Due to the efficacy of the selecte emulsifiers in the presence of relatively high amounts o polyols, coalescence of individual water droplets present i the oil phase is low. In this way, the emulsion according t the invention adequately prevents the migration of non-oi soluble compounds between individual water droplets in th emulsion. Polyglycerol polyricinoleate (Admul™ WOL 1403) was foun to be particularly useful in combination with phytase. Polyglycerol polyricinoleate is liquid at roo temperature and does not require heating up prior to o during mixing with oil. The viscosity of the emulsion remain low when using polyglycerol polyricinoleate and almost n droplet flocculation occurs. In addition, the use o polyglycerol polyricinoleate allows for a high concentratio of the water phase in the emulsion. Oils used in the emulsions of the present invention ar the oils normally used in food, feed or cosmeti preparations. They include fish oil, soya oil, rapeseed oil olive oil, cornflower oil, palm oil, avocado oil an different mineral oils. The invention further discloses a method for th preparation of said water-in-oil emulsions. The emulsions can be prepared by imput of a high amoun of energy. For example by severe stirring or by applying hig shearing forces. In this way, stable emulsions are obtained which can be stably stored in this form. The present invention discloses emulsions which ar stable during a long storage time. The emulsions are stabl for one month, more preferably for six months, mo preferably for more than a year. The water-in-oil emulsions according to the prese invention can be employed as additives for food, feed cosmetics. The use of the emulsions of the invention enables foo feed or cosmetic manufacturers to apply labile compounds process steps which would otherwise lead to deactivation said labile compounds. Furthermore, the use of the emulsio of the invention adequately prevents the migration of non-o soluble compounds from a feed, food or cosmetic compositi to the water phase of the emulsion. In this way, the labi compound(s) of interest present in the water phase of t emulsion is/are adequately protected against chemical enzymatical incompatibilities present in the composition which the emulsion is added. The emulsions of the present invention are used in t preparation of human or animal food or feed particle especially in the preparation of particles for fish poultry feed. Preferably, the emulsions are added by sprayi on food or feed particles. The addition can also be perform under reduced pressure, as described in International Pate Application WO 93/14645. The emulsions can be used as such to apply to the fo or feed particles. Preferably, the emulsions are diluted an oil or fat before addition to the food or feed particle An advantage of this process is that the concentrated labi compound can easily, that is with low energy input, homogeneously mixed with the oil phase. In this way an ev distribution of the active compound in the oil is guarantee The oil, which then contains the diluted desired compound c subsequently be sprayed on the food or feed particle. Th process requires a minimal investment in preparing the fin mixture to be sprayed on the particles. In another application the emulsion of the prese invention can be used to improve the degumming of soy a rapeseed oil. In this case the emulsion is containi phospholipase A2. Degumming is the removal of lecithin fr the indicated oils. The use of phospholipase for degummi has been extensively described in EP 0 513 709. This enzy improves the water solubility of non-hydratab phospholipids, improving their removal from the oil. T water-in-oil emulsions of the present invention facilita the addition of the phospholipase to the indicated oils. Below some examples are presented, which only functi to illustrate the present invention and in no way are mea to limit its scope. Example 1 Physical stability of water-in-oil emulsions using different emulsifiers and different enzymes la. Composition of enzyme solutions Stabilities of the various water-in-oil emulsions we demonstrated using a food-grade, neutral protease and a fee grade phytase. The standard solution of the protease contained 20 g Protease B500 (Gist-brocades, Holland) dissolved in 80 g water. After complete dissolution, either sorbitol glycerol was added and dissolved to reach the designat concentration. The standard solution of phytase contained either t raw fermentation concentrate (Natuphos ® UF concentrat obtained by ultrafiltration of a germ-free Aspergill culture filtrate) or the standardized fermentation produ Natuphos ® 5000 (Gist-brocades, Holland) containing 4 sorbitol. The phytase solutions used in the vario experiments contained glycerol or sorbitol in e concentration between 35 to 50%. lb. Emulsions prepared with Span™ 80 / Tween™ 80 mixtures To 5 g of fish oil (capelin oil as obtained fr Skretting, Norway), 0.5 g of either Span™ 80 or Tween™ emulsifier (both from Brocacef, the Netherlands) was adde Additionally, an emulsifier mix was prepared containi different ratios of the above prepared Span™ 80 and Tween™ 8 solutions. After thorough mixing, 0.18 g of one of the above described stabilized enzyme solutions was added, followed b extensive vortexing. All emulsions containing either protease or phytase i combination with one of the various Span™ 80 and/or Tween™ 8 emulsifiers showed separation of the oil and aqueous laye within a few hours at room temperature. lc. Emulsions prepared with lecithin-based emulsifiers Emulbesto™ 2000, Emulfluid™ E and VP627 are al lecithin-based emulsifiers and obtained from Lucas Meyer Germany. Following the approach outlined under (lb) emulsions were prepared using 0.5 g of each of the above mentioned lecithin-based emulsifiers. Within a few hours al emulsions prepared with these emulsifier products showe separation of the oil and aqueous layer. Id. Emulsions prepared with monoglyceride emulsifiers Hymono™ 1163 and Hymono™ 7804 were obtained from Quest Holland. Under gentle stirring 24 g of Hymono™ (a monoglyceride E471) is dissolved in 700 g of fish oil at a temperature o 70°C (Hymono™ 1163) or 50°C (Hymono™ 7804) . Subsequently, th solution is cooled down till at least 50"C. Using a hig speed homogenator (Ultra Turrax) , 200 g of enzyme solution i dispersed in the emulsifier-containing oil phase and th emulsion is cooled down to room temperature. After a perio of a few days, the water phase showed very limite sedimentation only. This sedimentation could be minimised b addition of palmitic acid. le. Emulsions prepared with polyglycerol polyricinoleate Admul™ WOL 1403 (polyglycerol polyricinoleate) wa obtained from Quest, Holland. In combination with labil compounds this emulsifier has several advantages, a.o. fact that Admul™ WOL 1403 is a liquid at room temperatu which allows easy dissolution in the oil phase. T circumvents the need for heating up the oil, so that t handling is easier and the labile compounds can be added the mixture of oil/emulsifier at room temperature, there minimising thermal stress. To prepare an emulsion with Admul™ WOL 1403, 3 g Admul™ WOL 1403 was mixed with 87.5 g of fish oil, follow by the addition of 25 g of Natuphos ® 5000 (stabilized wi 50% sorbitol) . The viscosity of the emulsion remained lo the droplet size of the water phase was about 2 μ and association of the droplets occurred. This indicates t excellent emulsifying property of Admul™ WOL 1403 in th system. The low viscosity allows a much higher concentrati of the water phase containing the enzyme in the fin emulsion. By increasing the quantity of Admul™ from 3 g to 9 g, appeared to be possible to emulsify a mixture of 75 Natuphos ® 5000 Liquid in 87.5 g fish oil. This emulsion physically stable for a period of 6 months at least. With t phytase enzyme, the Admul™ emulsion is superior over t Hymono™ emulsions in terms of flocculation behaviour and physically more stable than the Hymono™ emulsions (see Tab 1) . Table 1. Comparison of the physical parameters and properti of the Hymono™ 1163 and Admul™ WOL 1403 emulsions. PHYSICAL PARAMETERS AND PROPERTIES HYMONO 1163 ADMUL WOL temperature to dissolve the emulsifier 70 β C R.T. temperature during addition of the enzyme 50'C R.T. energy to prepare the emulsion high low viscosity of the emulsion medium low droplet flocculation medium low droplet size 2-10μ 2μ maximal concentration of water phase in the ca 22% ca 44% emulsion (w/w) (w/w) Example 2 Enzyme activity in a neutral protease water-in-oil emulsion Solution A: Under gentle stirring 5 g of a spray dried Protease B5 preparation is dissolved in 20 g demi water. The protea solution is diluted with glycerol to obtain a final glycer concentration of 50%. Solution B: Under gentle stirring 6 g of Hymono™ 1163 is dissolv in 175 g of fish oil at a temperature of 70°C. Subsequently, the solution is cooled down to 50°C. Using a high speed homogenator, Solution A is dispers in Solution B. The emulsion is cooled down to ro temperature. The protease activity of the protease water-in-o emulsion is about 17,000 U/g emulsion. The recovery protease from both Solution A and the water-in-oil emulsi was approximately 90%, which illustrates that emulsificati has no significant detrimental effects on proteolyt activity. The storage stabilities of the emulsion kept either 25°C or 35°C are shown in Table 2. Table 2. Storage stability of the protease emulsion preparation. TIME PROTEOLYTIC ACTIVITY DROPLET DIAMETER 25°C 35"C (week) u * /g % u * /g % 25°C 35 0 C emulsion emulsion 0 16,926 100 16,926 100 2 - 10 2 - 10 1 12,078 71 14,719 87 2 - 10 2 - 10 2 19,957 118 17,446 103 3 17,056 101 14,892 88 4 15,281 90 14,113 83 5 14,848 88 12,468 74 6 15,844 94 7,143 42 2 - 10 2 - 10 7 13,420 79 10,736 63 5 — — 2 - 15 (month) A unit of protease activity is the amount of enzyme activity which produces an amount of hydrolysate from casein (Hammersten, Merck) at pH 7.0 and 37°C, having a similar optical density at 275 nm as a tyrosine solution of 1.5 μg/ l Example 3 Enzyme activity in a stable phytase water-in-oil emulsion %■ Solution A: Under gentle stirring 100 g sorbitol is dissolved in 100 g of Natuphos ® UF-concentrate. Solution B: Under gentle stirring 24 g of Hymono™ 1163 is dissolved in 700 g of fish oil at a temperature of 70°C. Subsequently the solution is cooled to 50°C. Using a high speed homogenator, Solution A is disperse in Solution B. The emulsion is cooled down to roo temperature. The recovery of phytase activity from both Solution and the phytase water-in-oil emulsion was approximately 90% This illustrates that emulsification has no detrimenta effects on the phytic acid degrading activities of th enzyme. Phytase activity was determined as described in EP 420 358. The storage stabilities of the emulsion kept at eithe 25°C or 35°C are shown in Table 3. Table 3. Storage stability of the phytase emulsio preparation. TIME PHYTASE ACTIVITY DROPLET DIAMETER 25°C 35°C U U * /g % C 35°C (week) u * /g % 25° emulsion emulsion 0 531 100 531 100 2 - 10 2 - 10 1 623 117 569 107 2 - 10 2 - 10 3 494 93 654 123 4 616 116 528 99 5 523 98 337 63 6 513 97 451 85 2 - 10 2 - 15 7 295 56 380 71 5 — — 2 - 15 (month) A unit of phytase activity is defined as that amount o enzyme which liberates inorganic phosphorus from 1.5 m sodium phytate at the rate of 1 μ ol/min at 37°C and at a p of 5.50 Example 4 Preparation of stable phytase and protease water-in-oil emulsions using polyglycerol polyricinoleate 4a. Phvtase/oil emulsion Either 3.0 g or 9.0 g Admul™ W 1403 was dissolved i 87.5 g fish oil, whereupon an emulsion was prepared with 75. g Natuphos ® 5000 containing 50% sorbitol, using an Ult Turrax during 2* 30 seconds at full speed. The Natupho which was stabilized with 40% sorbitol has been brought 50% using additional sorbitol. As a result, the calculat activity will be 4100 U/g instead of 5000 U/g. The breaking of the emulsion: The emulsion is slowly deep frozen until -20°C and kept at this temperature during 20 hours. Subsequently, it i brought to room temperature and centrifuged at 20,000 rpm i a Sorvall centrifuge (SM 24 rotor) for 30 minutes. Duri this treatment the temperature is 20-25°C. The emulsion containing 3.0 g of emulsifier is no separated in 3 layers, i.e. a clear oil layer, a thi interphase and a clear water layer. In this water laye phytase activity has been determined to be 3750 U/g demonstrating that phytase activity has been recovered for a least 90%. The emulsion containing 9.0 g of emulsifier could not b separated by centrifugation. Kept at room temperature, th latter emulsion remained physically stable for a period of months at least. This observation is in accordance with t superior stability of the phytase emulsion described i Example 1. 4b. Protease/oil emulsion A mixture of 87.5 g fish oil, 3. Og Admul™ WOL 140 (dissolved in fish oil) and 75.0 g Protease B500 in solution of 50% sorbitol was homogenized in the same way described above for the phytase/oil emulsion. Qui surprisingly, the combination of this proteolytic enzyme wi the Admul™ WOL emulsifier generated emulsions which exhibit a decreased stability as compared to the stability Protease B500 in combination with the Hymono™ emulsifier (s Example 2) . Obviously, the Hymono™ emulsifier is to preferred in preparing the protease B500 emulsions. Example 5 Stability of phytase in emulsions containing proteases To demonstrate the protecting effect of the emulsion incompatible compounds, water-in-oil emulsions containi both phytase and an acid protease were made. This examp demonstrates that a mixture of emulsions containing eith the phytase or the acid protease in an aqueous phase is mo stable than an emulsion containing the two enzymes mixed one aqueous phase. Materials Natuphos ® UF concentrate (stabilized with 50% sorbitol b diluting a 70% sorbitol solution obtained from Roquett Freres, France) . Fromase ® 150 TL (a liquid acid protease from Mucor iehei a obtained from Gist-brocades) . Admul™ WOL 1403 (from Quest, Holland) . Fish oil (capelin oil from Skretting, Norway) 5a. Natuphos ® /oil emulsion Following the protocol outlined in Example 4, a stabl emulsion was obtained by dissolving 6 g Admul™ WOL in 87.5 fish oil and subsequent vigorous mixing of the oil with 75 Natuphos ® UF concentrate. The emulsion was kept at 20°C. first sample was immediately frozen at -20"C. 5b. Fromase ® /oil emulsion Two ml of Fromase ® 150 TL were added to 98 ml wate containing 50% sorbitol. The standard emulsion was prepare by mixing 87.5 g fish oil, 6 g Admul™ WOL and 75 g of th Fromase ® solution. The emulsion was kept at 20°C. 5c. The mixed emulsion Immediately after preparation of emulsions (5a) an (5b) , a mixed emulsion was prepared by adding 100 ml of th Natuphos ® /oil emulsion to 100 ml of the Fromase ® /oi emulsion. After thorough handmixing, the mixture was stor at 20°C. A first sample was immediately frozen at -20°C. 5d. Natuphos ® -Fromase ® /oil emulsion To 75 g of the Natuphos ® UF concentrate with sorbit 750 μl of Fromase ® TL was added and then mixed. Addition 87.5 g fish oil containing 6 g Admul™ WOL followed vigorous mixing yielded the desired emulsion. The emulsi was stored at 20"C. A first sample was immediately frozen -20°C. 5e. Stability of phytase in the various emulsions Kept at 20°C, the various emulsions were sampled after and 10 days of storage and immediately frozen at -20°C. Aft at least one night at -20°C, the various samples were thaw and centrifuged as described in Example 4. Phytase activiti were determined by samples taken from the aqueous laye Assuming 100% activity in the various samples obtained fr the Natuphos ® /oil emulsion (5a) , the following phyta activities were recorded after 5 respectively 10 days storage. In the mixed emulsion (5c) : 94% respectively 96% of t initial phytase activity. In the Natuphos ® -Fromase ® oil emulsion (5d) : 80% respective 78% of the initial phytase activity. Taking into account that the proteolytic activity of t Fromase ® is relatively low due to the presence of t sorbitol, the data illustrate that the emulsion adds to t stability of formulated labile compounds. Phytase protected against proteolytic attack when separate emulsified from the protease. Example 6 Stability of vitamin C in feed containing chemical incompatibilities Apart from the stabilizing effect observed in Example using two incompatible enzymes in a single emulsion, similar effect was observed in exposing vitamin C (ascorb acid) to feed particles. The incompatibility of ascorbic acid and trace minera like copper and iron is well documented (see for example C Handbook of Food Additives, second edition, page 85 a further) . However, nutritionists may advise combinations both iron and ascorbic acid for certain feed application su as broiler finisher feed. This example demonstrates th ascorbic acid incorporated in an emulsion is significantl more stable than a non-emulsified ascorbic acid soluti after mixing with broiler finisher feed pellets. Materials Soy oil (refined from OPG Farma, Holland) Admul™ WOL 1403 Glycerol 86% Citric acid (monohydrate p.a.) Ascorbic acid (p.a.) Broiler finisher feed (obtained from Arkervaart, Holland) 6a. Acrueous solution of ascorbic and citric acid The water phase was prepared by dissolving 1 g citri acid and 4 g ascorbic acid in 45 g demi water. The pH of th aqueous mixture obtained was approx. 2.4. After complet dissolution, 50 g of glycerol was added and the mixtur thoroughly mixed. 6b. Ascorbic acid/oil emulsion Following the protocol outlined in Example 4, a stabl emulsion could be obtained dissolving 3 g Admul™ W 1403 i 87.5 g soy oil and adding 75 g of the aqueous phase specifie under 6a. 6c. Dilution of the ascorbic acid/oil emulsion in fat The emulsions are intended to be used after dilution i oil or liquified fat. The diluted emulsion is sprayed ove the pelleted or extruded feed. To mix the emulsion with t fat, 100 ml of the emulsion (6b) was added to 100 ml of s oil after which the liquid was thoroughly hand mixed. 6d. Mixing of the ascorbic acid/fat emulsion and the aqueo ascorbic acid solution with broiler finisher feed Starting from either the ascorbic acid fat emulsion the aqueous ascorbic acid solution, equal quantities ascorbic acid (200 ppm final concentration) were applied broiler finisher feed pellets obtained from a local supplie To that end 200 ml of the oil emulsion was sprayed on 10 of feed pellets rotating in a concrete mixer. Similarl 50 ml of the aqueous ascorbic acid mixture (6a) was spray on 10 kg of feed pellets rotating in the concrete mixer. Th an additional quantity of 100 ml soy oil was sprayed on t same pellets. Immediately after spraying and subseque sampling, the samples were analysed for ascorbic acid pl dehydro ascorbic acid. 6e. Analysis of ascorbic acid in broiler finisher feed Ascorbic acid plus dehydro ascorbic acid were analys using the dehydro ascorbic/ascorbic acid test as describ in: Methods of Biochemical Analysis and Food Analysis usi Single Reagents (Boehringer Mannheim, 1989) . 10 g of pellets were extracted with 10 ml of acetone f 10 min (to dissolve the fatty material) , after which 90 ml demi water containing 1 g/1 Na-EDTA was added. After mixi the pellets and aqueous phase in the Ultra Turrax for 1 mi the samples were centrifuged. Using kit No. 4096 (Boehringer Mannheim) , the levels of ascorbic acid a dehydro ascorbic acid in the supernatant were determined. From the pellets sprayed with the aqueous ascorbic ac solution, 20% of the ascorbic acid could be recovered. contrast, from the pellets sprayed with the diluted ascorb acid/oil emulsion, 90% of the ascorbic acid was recovere This illustrates the protective effect conferred by t emulsion on ascorbic acid stability in a feed preparation.

Claims: Claims 1. A water-in-oil emulsion characterized in that i comprises the following components: water, oil, a labil compound, a stabilizing agent and an emulsifier. 2. An emulsion according to claim 1, characterized i that the stabilizing agent is a water activity loweri agent. 3. An emulsion according to claim 1, characterized i that the stabilizing agent is a polyol. 4. An emulsion according to claim 3, characterized i that the polyol is selected from the group comprisin glycerol, sorbitol, sucrose, poly propylene glycol, lactose trehalose, maltodextrins and glucose. 5. An emulsion according to claim 3 or 4 , characterize in that the polyol is present in the water phase of th emulsion in a concentration of at least 10%, preferably in concentration of 10-70%, more preferably in a concentratio of 30-70% (w/w) . 6. An emulsion according to claim 1, characterized i that the emulsifier is selected from the group of emulsifier which give rise to a water-in-oil emulsion. 7. An emulsion according to any one of the claims 3 t 5, characterized in that the emulsifier is active in th presence of high concentrations of the polyol. 8. An emulsion according to claim 6 or 7 , characterize in that the emulsifier is selected from the group o monoglycerides and polyglycerol polyricinoleate. - 21 - 9. An emulsion according to claim 1, characterized that the labile compound is selected from the gro comprising enzymes, vitamins, vaccines and colourants. 5 10. An emulsion according to claim 9, characterized that the enzyme is selected from the group comprisi proteases, carbohydrases, lipases, phospholipase oxidoreductases and phytases. 10 11. Use of an emulsion according to any one of t claims 1 to 10 in the preparation of a human or animal fo or a cosmetic. 12. A human or animal food or a cosmetic comprising 15 emulsion according to any one of claims 1 to 10. 13. A method for treating a food or feed partic characterized in that a stable water-in-oil emulsi containing a labile compound of interest is used to spray t 20 particles.

Inventors: EDENS LUPPO, MEIJER DIRK, VAN PARIDON PETRUS ANDREAS, EDENS, LUPPO, MEIJER, DIRK, VAN PARIDON, PETRUS, ANDREAS
Applicants: EDENS LUPPO, GIST BROCADES BV, MEIJER DIRK, PARIDON PETRUS ANDREAS VAN, EDENS, LUPPO, GIST-BROCADES B.V., MEIJER, DIRK, VAN PARIDON, PETRUS, ANDREAS
Application year: 1995
Main classification: A23K1
IPC codes: A23K1, A23L1, A61K8, A61Q19, B01F17, B01J13, C11B5, C12N9