IMPROVED PROCESS

The present invention relates to a new process for the production of a more stable vitamin C (or derivative of vitamin C) formulation.

Vitamin C is crucial in farmed fish and shrimp. Fish and shrimp are unable to synthesize vitamin C themselves, so it must be obtained through their diets.

Vitamin C is needed for:

'Growth and development

•Reproduction

•Wound healing

•Resistance to disease and immune system strength

Vitamin C has also some issue with its stability and therefore needs to be protected.

It is also common in the field of aquaculture to use a derivative of vitamin C instead of vitamin C. A very common and widely used derivative of vitamin C is L-ascorbyl-2-mono- phosphate.

L-ascorbyl-2-monophosphate is a more stable derivative form of vitamin C, which is has excellent properties and which is now used in many fish and shrimp farms.

This vitamin C derivative is L-ascorbyl-2-monophosphate, which is represented by the following formula (I)

Such vitamin C derivatives are commercially available for example from DSM under the trade names ROVIMIX® STAY-C ^® 35 and STAY-C ^® 50. In some application, L-ascorbyl-2-monophosphate is added on to the feed form and then coated with oil, before it is fed to the fish or shrimp. Such an application form has the disadvantage that some of the vitamin C (or the derivative) is lost when the form is soaked in water for a longer time. Therefore, the goal of the present invention was to find a way to make the formulation more stable with a process, which is easy to be carried out.

Surprisingly it was found that when the vitamin C (or the derivative) is mixed with at least one gum and then suspended in water before added on to the feed form, a more stable feed form is obtained. Additionally, this process can be carried with a minimal technical equipment. In fact, it could be carried out with kitchen appliances or even without any electrical equipment.

Therefore, the present invention relates to a process (P) for producing a feed formulation comprising the following steps

(i) a gel is formed by adding vitamin C and/or at least one derivative of vitamin C is added to at least one gel-forming compound chosen from the group consisting of the at least one gel-forming compound is chosen from the group consisting of alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc), and the mixture is gelled,

(ii) the gel of step (i) is mixed with (commercially available) fish or shrimp feed.

The so obtained formulation is more stable in regard to the loss of vitamin C (and/or derivative of vitamin C) while immersed in water.

This is a very important advantage for the fish or shrimp farmer.

Due to the simplicity of this process, it is possible to use simple household (kitchen) appliances (such as an electric mixer) or just an eggbeater.

It is clear that the process can also be carried out with equipment, which is used industrially. The so obtained improved formulation is a feed formulation for fish and/or shrimps. Therefore, all ingredients as well as their amounts used in the process according to the present invention are such ingredients and amounts thereof, which are approved for such feed for- mulations.

The various steps of the process are discussed in further details.

Step (i): (vitamin C and/or at least one derivative of vitamin C is added to a gel-forming compound and the mixture is gelled)

The first step is done according to the prior art.

Typical gel-forming compounds include natural gums, starches, pectins, gellan, agar-agar and gelatin. Often, they are based on polysaccharides or proteins.

Suitable gel-forming compounds are for example:

alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc). Therefore the present invention relates to a process (P1 ), which is process (P), wherein step (i) the at least one gel-forming compound is chosen from the group consisting of alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc).

The gelation process of the gelling agent can be initiated as commonly known. Very often the gelation is initiated by cations (such as Ca ²⁺ , Mg ²⁺ , Na ⁺ and K ⁺ ), which are added to the gel-forming compounds as an aqueous solution of a salt (such as CaC , MgC , NaCI, and KCI).

Usually and preferably the vitamin C and/or the vitamin C derivate is added to water and then the gel-forming compound is added and finally the gelling process is carried out. It is also possible to add the solution of vitamin C and/or the vitamin C derivates to the gel- forming compound.

In case a vitamin C derivate is not very well water-soluble (such as for example L-ascorbyl- 2-monophosphate) then it has to transformed into a water-soluble form.

L-ascorbyl-2-monophosphate for example is transformed into a water-soluble salt. Step (i) is usually carried out at ambient temperature. There is no need to heat the mixture.

Step (ii): {the gel of step (i) is mixed with (commercially available) fish or shrimp feed)

In this step, the gel, which is obtained from step (i), is added to the feed formulation. The feed can be any kind of feed (also commercially), which is to be fortified by vitamin C and/or a derivative of vitamin C (or the feed is added to the by vitamin C and/or a derivative of vitamin C).

The mixing is carried out under stirring (mechanical stirring or stirring by hand).

The so obtained fortified feed formulation can be used as such or if needed can be further fortified and/or brought in any other suitable application form.

Furthermore, more is also possible that the process according to the present invention can have additional steps. It is also possible that the formulation can be dried after the gelation. This can be of an advantage when the process is carried out not at one single location and/or at the same point in time. The spray-dried form can be stored and this form is storage stable.

Therefore, the present invention relates to a process (P2) for producing a feed formulation comprising the following steps

a. vitamin C and/or at least one derivative of vitamin C is added to at least one gel- forming compound chosen from the group consisting of the at least one gel- forming compound is chosen from the group consisting of alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc) and gelled,

b. the gelled form of step a is spray dried

c. the spray dried form of step b is mixed together with at least one gum and this mixture is suspended in water

d. the suspension of step c is mixed with (commercially available) fish or shrimp feed. Therefore, the present invention relates to a process (P3) for producing a feed formulation consisting of the following steps

a. vitamin C and/or at least one derivative of vitamin C is added to at least one gel- forming compound chosen from the group consisting of the at least one gel- forming compound is chosen from the group consisting of alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc) and gelled,

b. the gelled form of step a is spray dried

c. the spray dried form of step b is mixed together with at least one gum and this mixture is suspended in water

d. the suspension of step c is mixed with (commercially available) fish or shrimp feed.

Steps (a) and (c) are in analogy the steps (i) and (ii) of process (P) and (P1 ).

The 4 steps (especially the 2 additional ones) are discussed in more details. Step (a): (vitamin C and/or at least one derivative of vitamin C is added to at least one gel- forming compound and gelled)

The first step is done according to the prior art.

Typical gel-forming compounds include natural gums, starches, pectins, gellan, agar-agar and gelatin. Often, they are based on polysaccharides or proteins.

Suitable gel-forming compounds are for example:

alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate agar, gellan, carrageenan, locust bean gum, pectin gelatin and modified cellulose (such as methyl cellulose, ethyl cellulose, etc).

The gelation process of the gelling agent can be initiated as commonly known. Very often the gelation is initiated by cations (such as Ca ²⁺ , Mg ²⁺ , Na ⁺ and K ⁺ ), which are added to the gel-forming compounds as an aqueous solution of a salt (such as CaC , MgC , NaCI, and KCI).

Usually and preferably the vitamin C and/or the vitamin C derivate is added to water and then the gel-forming compound is added and finally the gelling process is carried out. It is also possible to add the solution of vitamin C and/or the vitamin C derivates to the gel- forming compound.

In case a vitamin C derivate is not very well water-soluble (such as for example L-ascorbyl- 2-monophosphate) then it has to transformed into a water-soluble form.

L-ascorbyl-2-monophosphate for example is transformed into a water-soluble salt.

Step (a) is usually carried out at ambient temperature. There is no need to heat the mixture. The amount of vitamin C and/or vitamin C derivate included in the gel can be adjusted according to solubility of vitamin C and/or vitamin C derivate.

Step (b): (the gelled form of step a is spray dried)

The gel, which is obtained from step (a) can now, be spray dried using commonly known spray drying processes.

A very suitable way to do so is by using a bench-top spray drier (about 120°C - 170°C inlet temperature and 50 - 90 °C outlet temperature).

The so obtained product can be stored it needed.

Step (c): (the spray-dried form of step b is mixed together with at least one gum and this mixture is suspended in water)

The spray-dried product obtained from step b is suspended in water and usually and preferably, at least one gum is added to the suspension. This gum can be natural or synthetic. Suitable gums are for example guar gum, xanthan gum, modified starch, and carboxyl me- thyl cellulose, and hydroxyl ethyl cellulose.

The suspension is produced usually under stirring.

Step (c) is usually carried out at ambient temperature. There is no need to heat the mixture. The ratio of the spray-dried product obtained from step b to the gum added in step c can be adjusted according to the targeted vitamin C and/or vitamin derivate concentration in fish/shrimp feed.

Step (d): (the suspension of step c is mixed with (commercially available) fish or shrimp feed) In this step the suspension, which is obtained from step (c), is added to the feed formulation. The feed can be any kind of feed (also commercially), which is to be fortified by vitamin C and/or a derivative of vitamin C (or the feed is added to the by vitamin C and/or a derivative of vitamin C).

The mixing is carried out under stirring (mechanical stirring or stirring by hand).

The so obtained fortified feed formulation can be used as such or if needed can be further fortified and/or brought in any other suitable application form.

The following Example illustrates the invention further without limiting it. All percentages and parts, which are given, are related to the weight and the temperatures are given in °C, when not otherwise stated.

Fig. 1 : Retention of Stay-C in feed pellets at the end of 10, 30 and 60 min immersion in water

Examples

Example 1 : 0.1 g of sodium citrate and 10 g of Stay-C ^® (from DSM) were dissolved in 75 g of deionized water in a glass beaker and mixed. Afterwards 0.08 g of low acyl gellan gum was slowly added into water with continuous mixing for 30 min.

Then 15 g of a 2% aqueous CaC solution was added drop by drop into solution to initiate gel formation with continuous mixing for 15 min.

Afterwards 100 g of the so prepared gel solution was pumped to a bench-top spray drier under mixing at 150°C inlet temperature and 66°C outlet temperature. The spray dried gel powder was collected and stored.

Then 10 g of this so spray-dried Stay-C ^® gel powder, 0.7 g of guar gum powder, and 0.3 g of xanthan gum powder were added together into 89 g of deionized water and mixed at 600 rpm for 20-30 min to obtain homogeneous suspension.

Finally 25 g of commercial shrimp feed was mixed with 0.5 g (20g/kg feed) of the prepared suspension in a round bottom flask by hand shaking followed by 15-30 min rotating in a rotatory evaporator to absorb the residual suspension on the flask.

The so obtained fortified feed formulation was then tested in view of the vitamin C stability. For that purpose, an immersion test was carried out.

The immersion test, the test feed (inventive embodiments) and the control feed were immersed into 1500 g of deionized water in a glass beaker and kept static throughout immersion test. The L-Ascorbate-2-Monophosphate level in the water was analyzed at 10, 30 and 60 min. Feed pellets were weighed and analyzed for dry matter content. Retention percent- age were then calculated.

The control feed was produced as follows: 10 g of Stay-C ^® was dissolved into 90 g of deionized water. 0.5 g solution was then sprayed onto 25 g of commercial feed, the same level of Stay C ^® as test feed.

The results of the test was summarized in Figure 1 , where it can be seen that the feed formulation which is produced according to process of the present invention shows an significantly improved stability!