The present invention relates to a composition, a method of preparation thereof and to the use of such a composition. In particular, the present invention relates to a composition which can be used for the preservation of prawn and the like, and to a method of preparation and use of such a composition. Furthermore, the present invention relates to a method of preparation and use of an aqueous solution of the composition and a concentrates of the solution.

Background Art

Blackspot (melanosis) is a dark pigmentation that forms on prawn and the like within a few hours of harvest. Whilst this pigmentation is thought to be relatively harmless, it reduces the commercial value and the acceptability of prawn and the like.

Surface discolouration resulting from the following series of biochemical reactions can occur if prawn and the like are kept out of water. In the presence of oxygen, the enzyme polyphenol oxidase (PPO), which occurs naturally in the shells of prawn and the like, converts monophenols (colourless) to diphenols. The so-formed diphenols are converted to highly coloured quinones which then react with amino acids to form complex brown polymers. The complex brown polymers appear as discolouration on the shells, which is often referred to as "blackspot".

Blackspot can reduce the commercial value and the acceptability of prawn and the like.

For several years, melanosis has been treated using sodium

metabisulphite solutions. However, the use of sodium metabisulphite solutions has several disadvantages. For example, sodium metabisulphite is corrosive and therefore hazardous to handle, and can be damaging to fishing vessels or processing areas. Also, sodium metabisulphite dipping solutions are often prepared onboard vessels by untrained personnel, thus the concentration of the solutions prepared can vary dramatically, and the prawn and the like can be dipped for too long. This is of particular concern as the Food Standards Agency maximum limit for sodium metabisuphite in foodstuffs is 150mg per kg, an amount which can be easily exceeded if the dipping solutions are too concentrated, or if the prawn and the like are dipped for too long.

A known alternative way to mitigate melanosis is to use treatments containing 4-hexylresorcinol. For example, EverFresh (SunOpta

Ingredients Group, Massachusetts) contains both 4-hexylresorcinol and sodium chloride in powder form, and is used in the inhibition of melanosis in shrimp, lobster, crab, prawn and crawfish. 4-hexylresorcinol is only partially soluble in cold water, and therefore available compositions containing 4-hexylresorcinol which are then made in a solution when required for use, typically at sea, suffer from the disadvantage that they do not properly dissolve in water. Thus, dipping treatments containing 4- hexylresorcinol in powder form are often inhomogeneous, particularly when prepared at sea by staff that are not chemically trained. Further, such treatments may be poorly mixed and/or may be prepared in contaminated containers, or using water which is not of suitable purity for application to foodstuffs.

Additionally, compositions comprising 4-hexylresorcinol have been formed which include green tea, as this was considered to enhance the

preservation of prawn. Green tea is a highly coloured and expensive natural product that contains anti-oxidants amongst other things. Whilst these compositions comprising green tea are expensive to produce it was believed that the anti-oxidant effect of green tea combined advantageously with 4-hexylresorcinol. Summary of the Invention

According to a first aspect of the present invention there is provided a preservative composition for use in the preparation of a solution for inhibiting melanosis in prawn and the like, said composition comprising an effective amount of a polyphenol oxidase inhibitor and a hydrotrope, wherein said composition does not comprise green tea.

In embodiments the weight ratio of PPO inhibitor to hydrotrope can be in the range 1 :2 to 1 :4.

Any reference herein to "prawn and the like" will be understood to mean prawns, nephrops, crabs and other such crustacean or shellfish that are susceptible to the formation of blackspot or melanosis. The term crustacean includes crabs, lobsters, crayfish, langoustine, shrimp, and prawn. In embodiments prawn can be decapod crustaceans. In embodiments the term "prawn" can include cold water prawn, warm water prawn, caridean shrimp, whiteleg shrimp, Atlantic white shrimp, Indian prawn, banana prawn and tiger prawn.

In embodiments the invention can be used to inhibit melanosis in cold water prawn and warm water prawn. In embodiments the invention can be used to inhibit melanosis in languoustine. In embodiments the invention can be used to inhibit melanosis in banana prawn. Any reference herein to "green tea" will be understood to mean a product made with the leaves of Camellia sinensis that has undergone minimal oxidation during processing. Therefore there is provided a composition in which green tea (and the anti-oxidants associated therewith) is absent.

The present inventor has demonstrated that the omission of green tea from such a composition for use in the preparation of a solution for inhibiting melanosis in prawn and the like does not significantly affect mitigation of melanosis, and in fact its omission provides the composition with improved qualities. For example, the composition does not stain the surfaces of vessels and processing areas, and improves the appearance of the treated prawn. Furthermore, in several countries, green tea is prohibited from use with foodstuffs and thus it is advantageous if a suitable composition can be provided which can inhibit melanosis in prawn and the like, but which does not include green tea. The composition, concentrate and solution of the invention are particularly suitable for use on boats to inhibit melanosis of prawns and the like, for example nephrops, crabs, crustaceans, and shellfish. Suitably, the composition may be provided as a kit of parts wherein the components of the composition can be added to water to provide a suitable concentrate or solution for use in inhibiting melanosis in prawn and the like. Preferably the polyphenol oxidase inhibitor of the composition, concentrate or solution can be 4-hexylresorcinol. 4-hexylresorcinol binds to the

Polyphenol oxidase (PPO) enzyme thereby rendering it incapable of catalyzing reactions and minimizing the development of blackspot. This binding to the PPO enzyme is thought to be non-reversible. The effective amount of 4-hexylresorcinol present in a resultant solution of the invention for use on prawn and the like may be at least 30 ppm, preferably at least 40 ppm, more preferably about 60 ppm per kg of prawn, in particular 62 ppm per kg of prawn and the like. At lesser concentrations of 4-hexylresorcinol in the solution for use, dipping times must be increased to provide a preserving effect. Thus, the components of the composition can be added to water such that an appropriate concentration of 4-hexylresorcinol is reached. Preferably the polyphenol oxidase inhibitor is present in a composition, prior to the addition of water, in an amount from about 13.2% w/w to about 16.8% w/w.

In embodiments the hydrotrope of the invention can be monopropylene glycol. Whilst it will be appreciated that other approved food grade hydrotropes could be used, monopropylene glycol has been found to be particularly advantageous.

In embodiments the weight ratio of PPO inhibitor to hydrotrope can be in the range 1 :3 to 1 :4, more preferably 1 :3 to 1 :3.5, more preferably around 1 :3.3. In such embodiments, the PPO inhibitor can be 4-hexylresorcinol and the hydrotrope can be monopropylene glycol.

Suitably, in embodiments, water can be added to the composition at a ratio of 1 :6.2 to 1 :10 of PPO inhibitor to water to allow the 4- hexylresorcinol to be provided in solution.

Use of a ratio of around 1 :6.2, in particular 1 :7.5 of PPO inhibitor to water, results in a very concentrated solution. Suitably for use embodiments of this very concentrated solution can be diluted by around 1500 fold with water. Use of a ratio of around 1 :9 to 1 :10, in particular 1 :9.3 of PPO inhibitor to water results in a concentrated solution which suitably can be further diluted with water (or more preferably sea water), by about a 1000 fold, for example 1 ml of solution makes about 1 L, to form a dilute solution which can be used to treat the prawns and the like.

Optionally the composition further comprises at least one of a pH reducer, and sodium chloride. In embodiments, the sodium chloride can be sea salt or pure dried vacuum (PDV) sodium chloride.

In embodiments the weight ratio of 4-hexylresorcinol to pH reducer, for example citric acid can be about 1 :2. In embodiments the weight ratio of 4- hexylresorcinol to sodium chloride can be about 2.5:1 . A suitable pH reducer may be citric acid, or an acceptable salt of hydrate thereof, in particular citric acid monohydrate. In embodiments, the pH reducer can suitably provide the composition, when provided with water, with a pH in the range of between 1 .07 to 1 .35, more preferably 1 .25 to 1 .35, in particular 1 .31 . In more concentrated solutions formed using the composition, the pH can be in the range 1 .07 to 1 .15.

Preferably the pH reducer can be present in a composition (without water added) in an amount from about 27% w/w to 33% w/w, more preferably about 28.1 % w/w to about 31 .7% w/w. Sodium chloride may be present in the composition in an amount from about 4.2% w/w to about 7.8% w/w.

The hydrotrope may be present in a composition (without water added) in an amount from about 46% to 54%, preferably about 47.4% w/w to about 51 .0% w/w. As will be appreciated, whilst the ratio of PPO inhibitor to hydrotrope can be kept within the range 1 :2 to 1 :4, the %w/w of these components in any composition of the invention may vary depending on the total components present in the composition.

In an embodiment, the composition (without added water) can comprise

Components of composition Weight %w/w

present

4-hexylresorcinol (PPO inhibitor) 25kg 23.36

Monopropylene glycol (hydrotrope) 82kg 76.64

In an alternative embodiment the composition (without added water) can comprise

Components of composition Weight %w/w

present

4-hexylresorcinol (PPO inhibitor) 25kg 15.92

Monopropylene glycol (hydrotrope) 82kg 52.23

Citric acid monohydrate (pH 50kg 31 .85

reducer)

In a further alternative embodiment, the composition (without added water) can comprise

Components of composition Weight %w/w

present

4-hexylresorcinol (PPO inhibitor) 25kg 21 .37

Monopropylene glycol (hydrotrope) 82kg 70.08

Sodium Chloride 10kg 8.55 In a further embodiment the composition can comprise

Suitably a sufficient amount of water can be added to the above compositions such that the 4-hexylresorcinol may be retained in the solution. In embodiments the water can be demineralised water. As discussed, an advantage of the present composition over other 4- hexylresorcinol compositions is its ability to be readily prepared and maintained in aqueous solution. A composition of the invention can be applied to prawn and the like to be preserved as an aqueous solution. It is advantageous to provide the composition of the invention as a solution as it enables it to be mixed more easily for use in applying to prawns and the like when on a boat. In preferred embodiments the composition of the invention is provided as a concentrated solution 1000x the concentration to which it is used to treat the prawns and the like. This is advantageous as it facilitates storage and transport of the composition and enables the composition to be readily diluted for use.

According to a second aspect of the invention there is provided an aqueous solution concentrate for inhibiting melanosis in prawn and the like comprising the composition as described herein as the first aspect of the invention and water wherein PPO inhibitor to hydrotrope to water can be in the range 1 :2:9 to 1 :4:10, preferably 1 :3:9 to 1 :4:10, more preferably 1 :3:9.3 to 1 :3.5:9.3, more preferably around 1 :3.3:9.3. In embodiments, the PPO inhibitor can be 4-hexylresorcinol and the hydrotrope can be monopropylene glycol and water can be demineralised water.

In an embodiment of the invention, a concentrated aqueous solution can comprise

In embodiments the polyphenol oxidase inhibitor can be 4-hexylresorcinol. In embodiments, the polyphenol oxidase inhibitor can be present in the concentrated aqueous solution in an amount from about 5.4% w/w to about 6.9% w/w.

The hydrotrope can be present in a concentrated aqueous solution made by the method in an amount from about 19.5% w/w to about 21 .0% w/w.

Where the concentrated aqueous solution includes a pH reducer, the pH reducer can be present in an amount from about 1 1 .6% w/w to about 13.1 % w/w. Where the concentrated aqueous solution includes sodium chloride the sodium chloride can be present in an amount from about 1 .9% w/w weight to about 3.2% w/w. The concentrated aqueous solution may comprise from about 58.0% w/w to about 59.5% w/w water.

According to a third aspect of the invention there is provided the use of a composition as described herein as the first aspect, or the concentrated aqueous solution as described herein as the second aspect when suitably diluted, in the inhibition of melanosis in prawn and the like.

Suitably, in embodiments the concentrate of the second aspect can be diluted by around 1000 times with sea water.

In embodiments the prawns and the like can be prewashed.

In embodiments of the method, the prawns and the like can be kept in contact with a solution of the composition of the invention for at least 7 minutes, suitably at least 8 minutes, preferably at least 10 minutes. In embodiments the solution of the invention can be used at less than 10°C when it is in contact with the prawns and the like. In embodiments the solution of the invention can be less than 5°C when in contact with the prawns and the like. In embodiments the solution of the invention can be in the range of 1 °C to 3°C when in contact with the prawns and the like.

As indicated, a solution of the invention can be a concentrated solution, for example x1000 concentration, as provided by the second aspect of the invention, which is further diluted with water or sea water, before it is used in the treatment of prawn and the like.

According to a fourth aspect of the invention there is provided an aqueous solution for inhibiting melanosis in prawns and the like, said solution comprising an effective amount of a polyphenol oxidase (PPO) inhibitor, a hydrotrope and water, (for example 4-hexylresorcinol, monopropylene glycol and water) wherein said composition does not comprise green tea.

In embodiments the weight ratio of PPO inhibitor to hydrotrope (for example 4-hexylresorcinol, monopropylene glycol) can be in the range 1 :2 to 1 :4, preferably in the range 1 :3 to 1 :4, more preferably 1 :3 to 1 :3.5, more preferably around 1 :3.3. In embodiments of a solution comprising PPO inhibitor, a hydrotrope and water, the effective amount of the PPO inhibitor for use on prawn and the like in the solution may be from at least 30 ppm, preferably at least 40 ppm, more preferably about 60 ppm per kg of prawn, in particular 62 ppm per kg of prawn and the like. The solution suitably can further comprise a pH reducer, for example citric acid, or an acceptable salt of hydrate thereof, in particular citric acid monohydrate. In embodiments the weight ratio of 4-hexylresorcinol to pH reducer, for example citric acid, can be about 1 :2. In embodiments the solution can further comprise sodium chloride. Suitably the weight ratio of 4- hexylresorcinol to sodium chloride may be about 2.5:1 .

Typically, in use, a concentrated solution of the invention is diluted with water, for example sea water, prior to use in the treatment of prawns and the like, for example prior to dipping of the prawns and the like.

According to a fifth aspect of the present invention there is provided a method of preparing an aqueous solution of the composition described herein, the method comprising the step of combining an effective amount of a polyphenol oxidase inhibitor and water wherein the water is provided at a temperature of from about 63°C to about 100°C, suitably around 63°C to about 90°C, suitably about 65°C to about 95°C, suitably around 65°C to about 90°C, at about 65°C to about 80°C, at about 70°C to about 75°C and a hydrotrope, for example monopropylene glycol. The temperature range used enables the polyphenol oxidase inhibitor to fully homogenise or dissolve in the water without being damaged, and without exposing the operator or the equipment to hazardous high temperature conditions.

Preferably in embodiments of the method of the invention the polyphenol oxidase inhibitor can be 4-hexylresorcinol. The method can comprise the further step of adding water at a temperature of approximately 30°C. In embodiments, at least one of a pH reducer and sodium chloride can be added with the additional water. Advantageously, the addition of water at 30°C helps dissolve the pH reducer, for example citric acid, and sodium chloride, and reduces the working temperature of the solution, whilst mitigating precipitation of the 4-hexylresorcinol.

Preferably the polyphenol oxidase inhibitor can be present in a

concentrated aqueous solution made by the method in an amount from about 5.4% w/w to about 6.9% w/w. In an embodiment, the method of preparing an aqueous solution of the composition can comprise the steps i) to iv) in the following order:

i) adding water at approximately about 63°C to about 100°C, suitably around 63°C to about 90°C, suitably about 65°C to about 95°C, suitably around 65°C to about 90°C, suitably at about 65°C to about 80°C, suitably at about 70°C to 75°C to a vessel;

ii) adding a polyphenol oxidase inhibitor;

iii) adding a hydrotrope; and

iv) adding water at approximately 30°C. The method may comprise the further step of adding a pH reducer and/or sodium chloride with the water at step iv).

In particular embodiments of the aqueous solution, the hydrotrope can be monopropylene glycol, and the pH reducer can be provided by citric acid, or an acceptable salt or hydrate thereof, typically citric acid monohydrate.

The hydrotrope can be present in a concentrated aqueous solution made by the method in an amount from about 19.5% w/w to about 21 .0% w/w.

Where the concentrated aqueous solution includes a pH reducer the pH reducer can be present in an amount from about 1 1 .6% w/w to about 13.1 % w/w. Suitably, in embodiments, the pH reducer can be citric acid monohydrate. Where a concentrated aqueous solution made by the method includes sodium chloride the sodium chloride can be present in an amount from about 1 .9% w/w weight to about 3.2% w/w. Further, a concentrated aqueous solution made by the method may comprise from about 58.0% w/w to about 59.5% w/w water. According to a sixth aspect of the invention there is provided an aqueous solution for inhibiting melanosis in prawn and the like prepared by the method as described herein as the fifth aspect.

According to a seventh aspect of the invention there is provided the use of an aqueous solution as described herein as the fourth aspect, or as described herein as the sixth aspect, in the inhibition of melanosis in prawn and the like.

Preferred and alternative features of each aspect of the invention are, where appropriate, as for each other aspect mutatis mutandis. The present invention will now be described by way of example only, with reference to the following Figures in which: Figure 1 is a graph showing the melanosis score for the cephalothorax dorsal of langoustines subjected to melanosis inhibiting treatments, and a control treatment;

Figure 2 is a graph showing the melanosis score for the cephalothorax ventral and parapods of langoustines subjected to melanosis inhibiting treatments, and a control treatment;

Figure 3 contains two graphs showing separately the melanosis score for the first clawed legs; and the pleopods of langoustines subjected to melanosis inhibiting treatments, and a control treatment; and

Figure 4 contains two graphs showing separately the melanosis score for the abdomen or tails; and the tail fan of langoustines subjected to melanosis inhibiting treatments, and a control treatment.

Figure 5 shows bottles of sample A, sample B and sample C after being stored at room temperature with from left to right the solutions being shown as Sample C, Sample B, Sample A. Figure 6 shows bottles of sample A, sample B and sample C after being stored at about 3°C with from left to right the solutions being shown as Sample A, Sample C, Sample B.

Example 1 A concentrated aqueous solution of a composition for use in the preservation of prawn and the like was prepared using the following process. The solution described below is a concentrated solution, which should be further diluted as described before it is used in the treatment of prawn and the like.

A batch of solution was prepared by firstly adding 75 kg of hot water (wherein the water is suitable for human consumption) at approximately 70°C to 75°C to a plastic mixing vessel. 25 kg of 4-hexylresorcinol was added to the hot water and the contents of the vessel were stirred until a dispersion was formed. 82 kg of monopropylene glycol was added. The so-formed dispersion was mixed until all components were dissolved thereby forming a solution. 58 kg of warm water at approximately 30°C with 50 kg of citric acid monohydrate and 10 kg of pure dried vacuum (PDV) sodium chloride salt was added to the solution including 4- hexylresorcinol and monopropylene glycol.

Samples of the solution were validated by quality control testing which checks the colour, density, pH and refractive index of the solution.

The order of addition indicated was found by the inventors to be the most effective way to ensure a homogenous solution was formed.

The quantities indicated above may vary by approximately ± 1 kg.

Therefore the "dry composition" (i.e., excluding water) may have from about 13.2% w/w to about 16.8% w/w of 4-hexylresorcinol. Furthermore, the monopropylene glycol may be present in an amount from about 47.4% w/w to about 51 .0% w/w. Again, based on the example above, the citric acid monohydrate is present in an amount from about 28.1 % w/w to about 31 .7% w/w.

Furthermore, the PDV salt may be present in an amount from about 4.2% w/w to about 7.8% w/w.

The % w/w values given above relate to the relative amounts of all components present except water. Clearly, the total amount of

composition must be 100%, and the relative amount of the components can be varied within the tolerances indicated to ensure that this is the case. This also applies to the concentrated aqueous solution described in more detail below.

The composition may also be provided as a concentrated aqueous solution.

For example, in the aqueous solution produced in Example 1 , the 4- hexylresorcinol is present in an amount from about 5.4% w/w to about 6.9% w/w, and the monopropylene glycol is present in an amount from about 19.5% w/w to about 21 .0% w/w. The citric acid monohydrate is present in an amount from about 1 1 .6% w/w to about 13.1 % w/w and the PDV salt is present in an amount from about 1 .9% w/w weight to about 3.2% w/w. The water is present in an amount from about 58.0% w/w to about 59.5% w/w. Example 2

The concentrated aqueous solution described in Example 1 can be used to preserve prawn and the like, and in particular is useful in the treatment of live and/or raw prawns and nephrops to mitigate or prevent the onset of discolouration of the prawns and nephrops, for example blackspot.

Furthermore, the composition in the aqueous solution described above may be provided without water and may be used to preserve a prawn and the like. The concentrated aqueous solution is used in the preservation of prawn and the like as described below. A dipping tank or bin is thoroughly cleaned using a suitable sanitiser such as Xyrex™ Xyresan™ (available from Xyrex™, Glasgow, UK). The concentrated aqueous solution of composition as described in Example 1 is thoroughly mixed (for example, by shaking) and is combined with sea water or a saline solution with approximately the same salt content as sea water (about 3% w/v to 4% w/v). A minimum of 1 part aqueous solution of composition to 1000 parts of saline solution should be used. However, a stronger solution can be used.

The so-formed mix is formulated in, or added to, the dipping tank or bin. The prawns to be treated are washed thoroughly using a suitable wash such as Xyrex™ U500 (available from Xyrex™, Glasgow, UK). The prawns are then soaked in the aqueous solution of composition in the dipping tank for between five and ten minutes to ensure effective coverage. It is advisable to soak the prawns for at least seven minutes to ensure that the maximum effect is achieved. Once treated, the prawns are boxed, iced and stored as normal.

Approximately 100 ml of concentrated aqueous solution of composition, as described in Example 1 , can be diluted to form 100 litres of dilute aqueous solution which is used to treat approximately 200 kg of prawn. Thus, 0.5 ml of concentrated aqueous solution of composition is used to make a dilute aqueous solution to treat 1 kg of prawn. It should be noted that 1 litre of concentrated aqueous solution weighs approximately 1 .1 kg.

Therefore, 0.5 ml of concentrated aqueous solution equates to

approximately 550 mg (i.e., 0.55 g) concentrated aqueous solution. Therefore, using the % w/w values from above, it can be calculated that approximately 0.5 ml of concentrated aqueous solution contains approximately 27.15 mg to approximately 34.55 mg of 4-hexylresorcinol; approximately 99.0 mg to approximately 101 .2 mg of monopropylene glycol; approximately 63.0 mg to approximately 65.40 mg of citric acid monohydrate; and approximately 8.65 mg to approximately 16.0 mg of sodium chloride; and can be combined with a saline solution to make a dilute solution for treating approximately 1 kg of prawn.

When the concentrated aqueous solution of composition is diluted as described above, the amount of each component is reduced by a factor of 1000. Thus, approximately 550 g of composition is suitable for treating approximately 1 kg of prawn. The dilute solution contains the following components in the following amounts: approximately 27.15 g to approximately 34.55 g of polyphenol oxidase inhibitor; approximately 99.0 ig to approximately 101 .2 g of hydrotrope; approximately 63.0 g to approximately 65.4 g of pH reducer; and approximately 8.65 g to approximately 16.0 g of sodium chloride; and can be used to treat approximately 1 kg of prawn.

In any event, the solution or composition should preferably be replaced daily. Example 3

Comparative studies were carried out to establish the effectiveness of the composition as described herein in the inhibition of melanosis in langoustine. Langoustine were collected by otter trawler in the Clyde sea area. Once onboard, the langoustine were washed and separated into five different groups to which the following treatments were applied: (a) "Un-dipped" - no treatment (control group); (b) "Normal PF" - composition as described herein plus 75 g to 90 g green tea per kg of langoustine; (c) "PF 50% tea" - composition as described herein plus 37 g to 45 g green tea per kg of langoustine; and (d) "PF 0% tea" - composition as described and claimed herein. After initial treatment, all langoustine were transported on ice to the

University of Glasgow for testing and analysis. On arrival, the langoustine were stored at 3 °C, and melanosis was scored on days 3, 5, 7, and 1 1 .

With reference to Figures 1 to 4, it is clear that the composition of the present invention inhibits the onset and progression of melanosis.

Furthermore, with reference to the "tail fan" graph in Figure 4, it is clear that after day 5 the composition of the present invention has a significantly lower melanosis score than the other compositions tested. Also, it was observed that the langoustines treated with the composition of the present invention generally had a better appearance than those treated with the other compositions, exhibiting less staining and colouration as the trial progressed.

Without wishing to be bound by theory, in the composition and aqueous solution described, the 4-hexylresorcinol is believed to act as a polyphenol oxidase inhibitor, the monopropylene glycol as a hydrotrope, and the citric acid monohydrate as a pH reducer.

It has surprisingly been found that the composition, and the aqueous solution of the composition, of the present invention can be used to preserve, in particular to mitigate or prevent blackspot or melanosis in prawn and the like. Also, the inventors have surprisingly discovered that the removal of green tea has no adverse impact on the effectiveness of the composition and can, in fact, provide improved product appearance after several days. Furthermore, the inventors have determined an optimised composition, provided as a pre-solvated aqueous solution, which provides a controlled amount and concentration of components.

The aqueous solution of composition is advantageously prepared using the method described herein. This has the advantage of enabling the 4- hexylresorcinol to be dissolved and homogenised in solution, without being damaged, and without exposing the operator or the equipment to hazardous and expensive high temperature conditions. Example 4

Bottles of three solutions (solution A, solution B, solution C) were provided and exposed to different test conditions. The components of each test solution are indicated below.

Solution A was a sample from a larger stock solution comprising

Components of composition Weight

present

4-hexylresorcinol (PPO inhibitor) 50kg

Monopropylene glycol (hydrotrope) 165kg

Water 467kg

Citric acid monohydrate (pH 100kg

reducer)

Sodium Chloride 20kg Solution B was a sample from a larger stock solution comprising

Solution C was a sample from a larger stock solution comprising

In a first test condition, a bottle of each of solution A, B and C was left at room temperature (~20°C) for 12 hours. Solution A was observed to maintain the 4-hexylresocinol in solution, whereas each of solution B and C was observed to have a separation of components in the solution.

In a second test condition, a bottle of each of solution A, B and C was stored at 3°C for around 8 hours after being stored at room temperature. It is considered that around 3°C would be a typical temperature experienced in working conditions at sea. In this second test condition, it was observed that in sample C including 0% monopropylene glycol, the 4 hexylresorcinol had solidified, in solution B, including 50% monopropylene glycol, the 4- hexylresorcinol was not solid, but the solution did move slower than at room temperature

At 3°C, the components of solution A remained in solution and the solution was as workable as provided at room temperature. Further, solution A has been stored at -6°C overnight and the 4- hexylresorcinol remained in solution.

Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes of carrying out the invention which are obvious to those skilled in the art are intended to be covered by the present invention.