Field of Invention

The invention relates to a novel food surfactant which contains lecithin and medium chain triglycerides.

Background of Invention

Food dehydrates in particle form or food powder (the term which will be used throughout the specification) are produced as drink or paste bases. The addition of water and subsequent dilution of the base enables drinks, high liquid-content foods and sauces as well as ice cream mixes to be prepared. Preparation of such bases results in long life compact bases, useful as convenience foods in kitchens or readily and simply converted in industrial applications. In order to minimize the need for much mechanical energy in effecting dilution, instant products have been developed, these readily sink in water and are easily dispersed into solutions with the expenditure of relatively little mechanical energy. Such bases are usually powders which are treated with surfactants to present a hydrophilic face to the water used in reconstitution.

Whereas some other compounds, for example alcohols or sucrose esters, exercise a surfactant type reaction which enable powders with free surface fats to be readily wetted, lecithin components are the most accepted nutritionally. Lecithin components are completely harmless and are even beneficial to human health. Moreover, they are among the most effective food surfactants known as they readily form a hydrophilic interface between oil and water thus facilitating the formation of emulsion. The lecithin carrier

The lecithin fractions of interest in food surfactant processes are best carried in oil as water suspensions need very high levels of refined lecithin components which are generally expensive. However, the conventional and present application of lecithin dissolved in oil to a powder surface involves preparing the highest concentration of lecithin in oil which is impractical for the following reasons. The oil component employed as the carrier is often undesirable nutritionally and further achieves rapid contact with oxygen thereby inducing oxidation which causes spoilage.

Commonly, 1 part of lecithin to 2 parts of oil by weight is employed. At high concentrations of lecithin, oil/lecithin surfactant solutions are extremely viscous and difficult to be atomized into the spray needed to ensure powder particle coverage. Although heating of the solution would reduce viscosity, temperatures of over 65 0C would denature the lecithin and reduce its efficiency and hasten the oxidation process of the oil. A compromise situation is usually sought where surfactant solutions are applied at around 60 0C and the particle coverage is subsequently optimized via surfactant application as a fine spray and the food powder being kept mobile during application to ensure adequate mixing.

Reduced lecithin activity is a risk if temperature is increased during the solution preparation, storage and application. In addition, the resulting food surfactant solution is easily subjected to oxidation and deterioration of flavor.

It is thus an object of the present invention to provide a carrier solution for lecithin which is novel over the conventional and existing carriers. Disclosure of Invention

In accordance with the invention, there is provided a food surfactant comprising lecithin fractionates, preferably in dry form, and medium chain triglycerides (MCT), said MCT functioning as a carrier for the lecithin. MCT occurs naturally in palm and/or palm kernel oil and is derived by means of fractionation. MCT has low melting points and thus remains liquid even at low temperatures

The very low viscosity of medium chain triglycerides enables higher lecithin concentrations to be used and finer application spray droplets to be formed. The resultant food surfactant would even show that less of said solution would be needed during its application to achieve good coverage of the food powder particles. In addition, the low viscosity of the MCT allows the surfactant solution to migrate over the surface of the food powder particles at temperatures down as low as 4°C, completing the enrobiment of the particle with surfactant and enabling better penetration of particle surface and interstitial free fat with the lecithin component of the surfactant, allowing the thus treated food powder to dissolve instantly be instantized in cold water. Moreover, the low viscosity of the resultant surfactant solution when prepared with medium chain triglycerides enables other materials to be carried in solution apart from the lecithin fractionates without affecting its viscosity.

It would be proven that a composition of lecithin in medium chain triglycerides alone has higher resistance to oxidation than compositions of lecithin in vegetable oils as employed in conventional and existing food surfactant solutions. Such high resistance would even be enhanced when sugar esters and/or tocopherol are added therefore is preferred that the food surfactant solution of the present invention also includes antioxidants such as sugar ester, tocopherol and/or ascorbic acid and ester, most preferably in the amount of 10 ppm to 200 ppm. The use of medium chain triglycerides as a reagent carrier is nutritionally desirable. Medium chain triglycerides are metabolized into energy in the human liver, unlike other fats and unlike these do not contribute to fat deposition. Medium chain triglycerides can therefore be used in diet applications.

A more detailed description of the food surfactant solution will be described as follows in accordance with the most preferred embodiment thereof.

Detailed Description of Invention

A preferred food surfactant solution according to the invention comprises lecithin fractionates in dry form dissolved in medium chain triglycerides (MCT) or C8 - C10 fatty acid esters of glycerols derived from caproic and caprylic acids. During application, the low viscosity of the MCT {as illustrated previously} at ambient temperatures provide efficient contacts between the resultant surfactant solution and the food powder particles, and hence, less food surfactants are needed to cover the food powder particles effectively.

A surfactant solution of 1 part of lecithin fractionates dissolved in 3 parts of MCT derived from glycerol tri-caproate/caprylate exhibits a viscosity of 7 mpa/s at 25°C while a surfactant solution of lecithin fractionate in soy bean oil at same conditions (concentration and temperature) exhibits a viscosity of 36 mpa/s. The relatively low viscosity of the surfactant solution of the invention facilitates the ease of effective particle coating on the food powders.

In addition, as MCT is remarkably stable and resists oxidation at modest temperatures, the food surfactant solution of the invention would function to provide an oxygen barrier to the treated food powders. To further enhance the anti-oxidant properties to the food surfactant, anti-oxidants such as alpha tocopherol and sucrose palmitic or any other natural and synthetic tocopherols and palmitic, oleic and stearic esters of sucrose could be added in the amount of up to 2% (by weight). Using the "Rancimat" test, it would be shown that the surfactant solution without the anti-oxidants has an induction or stability period of between 210 and 400 hours at 1000C. The induction period then increased to between 900 and 1300 hours subsequent to adding 100 ppm (weight) of synthetic alpha tocopherol and 50 ppm (weight) of sucrose palmitate.

In comparison, similar tests conducted on surfactant solution of lecithin in anhydrous milk fat or soy bean oil with and without anti-oxidants exhibit an induction period of between 5 to 10 hours at 1000C.

The following tests were also conducted: -

(i) Flavor Deterioration

A standard sample of agglomerated whole milk powder of 28% total oil and 3% free oil was incubated at 500C in the presence of air in a sealed container. The following samples were then prepared: Sample 1 - similar milk powder treated with 0.6% (weight) of a 1:3 (weight) surfactant solution of lecithin fractionate in corn oil. Sample 2 - similar milk powder treated with 0.6% of a 1 :3 (weight) surfactant solution of the invention.

Both Samples 1 & 2 were subjected to the same condition as the standard sample. All three (3) samples were then examined at daily intervals (15% solution water) and revealed the following result: - Unacceptable flavour was detected from the standard sample and Sample 1 after six (6) days and only after twenty-six (26) days from Sample 2.

When the test was repeated with incubation at 250C, Sample 2 remained wholesome for 19 months while flavour deterioration was detected from the standard sample and Sample 1 following 3 to 6 months.

(ii) Solubility

13.0 g of the Sample 2 dissolved in 100 mis. water at 26°C in 12 seconds while the same quantity of standard sample and Sample 1 failed to be dissolved even after 15 minutes of stirring.

In addition to these tests, the following test was conducted: -

A chocolate drink base prepared by blending sugar, modified starch, whole milk powder, non dairy cream, vanilin powder, chocolate powder and appropriate quantity of the surfactant solution of the invention yielded a homogeneous and dust free resultant powder. 28g of the powder dissolved in 100 mis. water at 8°C in 24 sec. Meanwhile, identical chocolate powder employing surfactant solution from Sample 1 failed to dissolve in water at 8°C.

Similar results were obtained after comparative treatments of non-dairy creamer, 3 in 1 coffee and cereal preparations, instant dessert mixtures, and infant feed.

Method of Application/s Application of the surfactant solution of the invention to food powder could be effected by spraying a mist of the surfactant solution over the surface of the powder during blending in a ribbon, screw or tumble blender or during mechanical or vacuum or pneumatic conveying of the same. It is not necessary to heat either the surfactant solution or the food powder.

Alternatively, the application of the surfactant solution could be effected by pouring the surfactant solution on to powdered sucrose, lactose or maltodextrin/glucose syrup solids and homogenizing the mixture by blending. Food powder is subsequently added and followed by additional blending for 5 to 10 minutes which should suffice to coat all particles.