WO2019178632A1 - Liquid composition containing a polymeric guanidine - Google Patents

Abstract

The invention relates to a liquid composition containing at least one polymeric guanidine and at least one wetting agent dissolved in an inorganic solvent, to the use of this composition for increasing the shelf life of harvested fruit and vegetables, or as a plant protection product against undesirable micro-organisms on the surface of harvested fruit and vegetables, and to a method for increasing the shelf life of harvested fruit and vegetables, or for combating undesirable micro-organisms, by applying this composition to the surface of harvested fruit and vegetables.

Description

 LIQUID COMPOSITION CONTAINING A POLYMERIC GUANIDINE

The invention relates to a liquid composition for increasing the shelf life of fruits and vegetables, comprising a polymeric guanidine.

Fruits and vegetables are especially important for a healthy diet. They contain a variety of important nutrients and trace elements. However, a supply of fresh fruit and vegetables is difficult, especially in winter.

After harvesting, fruits and vegetables are able to survive on their own. This means that metabolic processes continue in a different way.

For example, some fruits and vegetables produce ethylene during storage. Ethylene is a gaseous phytohormone that affects the maturation of fruits. Fruits which release ethylene during storage are, for example, apples, apricots, avocados, pears, kaki fruits, kiwi, mango, melons, nectarines, papaya, peach, plums, tomatoes. This causes an acceleration of breathing, aging and maturation in many other species. Fruits that are particularly susceptible to airborne ethylene, and therefore spoil significantly faster, include eggplant, bananas, cauliflower, broccoli, chicory, peas, green beans, cucumbers, lettuce, pumpkins, carrots, peppers, parsley, Brussels sprouts, Watermelons.

During storage, fruits and vegetables undergo various changes. Recognizable to the naked eye are the changes in the external appearance. A consequence of the storage is shown by fading or yellowing. Ethylene can cause discoloration in salads and cucumbers. By the release of water or the expiring transpiration and due to cellular respiration wilts and shrinks fruit and Vegetables during prolonged storage. Finally, rot or mildew can occur, which is caused by microbiological attack.

Less obvious is the loss of nutritional quality. Long-term storage causes many fruits and vegetables to lose significant amounts of nutrients. Particularly high are the losses in the group of vitamins. Of these, especially vitamin C, carotenoids, vitamin B1 and folic acid are affected during storage.

Another key quality feature in fruits and vegetables is the taste. Storage often flattens the taste of fruits and vegetables and may cause an undesirable off-taste.

For these reasons, there is a change in the quality of fruits and vegetables during storage. It is therefore necessary to preserve plant foods.

When properly stored, these undesirable phenomena can be delayed for different amounts of fruit and vegetables.

 The influence of ethylene can be reduced, e.g. by separate storage of ethylen-donating varieties and ethylene-sensitive varieties avoided. However, this is often not possible without problems.

Another important measure to extend the shelf life of fruits and vegetables is the lowering of the storage temperature. This achieves a slowing of cellular respiration, metabolism and enzymatic degradation processes. In addition, microorganisms are restricted in their growth.

Other measures are known to prevent the spoilage of food by microorganisms. For example, irradiations with ultraviolet or ionizing radiation are known. The disadvantage of this is that after sterilization a renewed infestation can not be avoided. However, it would be desirable to also protect the food from re-infestation.

In the field of disinfectants, for example, polymeric guanidines have long been known.

 WO 2008/080184 describes the use of polymeric guanidines for controlling microorganisms.

 Also known is the use of polymeric guanidines in agriculture. EP 2 084 967 describes the treatment of banana trees. The polymeric guanidine is injected into the plant.

However, this type of application is not suitable for already harvested fruits and vegetables. Residues on or in food should be avoided and subject to strict controls.

The object of the invention is therefore to provide an improved method for increasing the shelf life of harvested and intended for consumption fruits and vegetables.

The invention is achieved by providing a composition according to claim 1. A composition according to the invention contains at least one polymeric guanidine, and at least one wetting agent dissolved in an inorganic solvent. It has surprisingly been found that the shelf life of fruits or vegetables intended for consumption is markedly improved by the composition according to the invention.

This opens up the possibility of freeing the surface of fruits and vegetables from unwanted microorganisms while at the same time preventing new infestations. The Composition can be used to control unwanted microorganisms by exposing the surface of harvested fruits and vegetables.

Polymeric guanidines have a good activity against microorganisms. By combining with the wetting agent, the surface of the vegetable food can be completely treated. Only partial wetting or dripping of the composition is avoided. It thus forms a flat layer on the surface of the vegetable food.

As a result of the polyaminosaccharide contained in the composition, the composition forms a film-forming layer on drying. This layer consists of the polyaminosaccharide and the polymeric guanidine. The polymeric guanidine remains attached to the surface of the vegetable food. As a result, as complete as possible protection of the surface of the vegetable food can be achieved. By having the composition as a solution in an inorganic solvent, this layer is easily removable before consumption of the food by washing, for example, in water. This is especially important in plant foods whose shell is to be suitable for consumption. This may be the case when the fruit or vegetables are usually consumed with shell, such as apples or pears. Or even if the shell itself is used, such as the shell of citrus fruits when baking.

The application of the composition to the fruit or vegetables can be done, for example, by spraying, brushing or misting. The misting is particularly suitable for use in containers, trailers, boxes and other transport containers. It is also possible to use dilutions of the composition, for example in the ratio 1: 4000. Another possibility is that the fruit or vegetables are dipped in the composition and kept therein for a given residence time. The residence time depends on the type of fruit or vegetable to be treated and is 1 to 5 minutes. Subsequently, the fruit or vegetables can be removed from the solution and dried, for example, in the air. The drying time depends on the climatic conditions.

As a wetting agent chitosan is particularly well suited. Chitosan is a poly (D) glucosamine or a deacetyl chitin. The degree of deacetylation is usually between about 60% and 100%. For the present composition, a degree of deacetylation of 80% to 90% is particularly advantageous. Chitosan has as natural product a particularly good compatibility. Even the consumption of chitosan is harmless according to today's findings. The composition of the polymeric guanidine with chitosan as wetting agent is particularly suitable for use to increase the shelf life of fruits and vegetables.

The film-forming layer reduces the release of liquid from the stored plant foods. This can dehydration, and as a result, the shrinkage, be reduced. The stored fruits and vegetables will stay fresh longer. The film-forming layer can also minimize the influence of ethylene on the harvested fruits and vegetables. This allows a common storage of different fruits, without having to accept limitations in durability.

In addition, this composition is particularly good washable with water. It has also surprisingly been found that washing not only the composition itself can be easily removed, but also common pesticides are washed off. The composition of the polymeric guanidine with Chitosan thus serves as a solubilizer for common pesticides and increases their water solubility. As a result, fruit and vegetables treated with the composition are also cleaned of pesticide residues during washing.

As the solvent in the composition, for example, water can be used. By using water, a harmless in the food industry solvent can be used. In addition, water is tasteless. Water evaporates without leaving residue and thus helps to form the protective layer. In addition, water has particularly good dissolution properties for polymeric guanidines and polyaminosaccharides.

Different polymeric guanidines can be used for the composition. The preparation of polymeric guanidines is described, for example, in WO 01/85676 A1 and in patents AT 408302 B and AT 411060 B. Polymeric guanidines also include, for example, or are referred to as Akacid, or X-cid, and are described, for example, in Kratzer et al. , Antibiotics Monitor 1/2/2006; Buxbaum et al. , Journal of Antimicrobial Chemotherapy (2006) 58, 193-197; US 2,325,586; GB 1095902 A; WO 1999/054291 A1; WO 01/85676 A1; WO 2002/030877 A1; WO 2006/047800 Al; WO 2008/080184 A2; WO 2009/092123 A2; EP 2520605 Al; WO 2013/064161 A1; WO 2014/113835 A1; WO 2016/015081 A1 (all incorporated herein by reference). The polymeric guanidine may also be in the form of a complex, for example with gelatin or a polysaccharide (for example as described in WO 2010/106007 A1). WO 2008/080184 describes the use of polymeric guanidines for controlling microorganisms in non-therapeutic applications, for example by nebulization for disinfecting the room. A composition referred to therein is Akacid, poly [2- (2-ethoxy) -ethoxy-ethyl-guanidinium chloride and Akacid Plus, a 3: 1 mixture of poly (hexamethylene guanidinium chloride) and poly [2- (2-ethoxy ) ethoxyethyl) guanidinium chloride]. Herein, the term "polymeric guanidines" in particular for "polymeric guanidine derivatives based on an alkylenediamine and / or an oxyalkylenediamine" (WO 2009/009815 Al), especially for "polymeric guanidine derivatives based on diamines which alkyl chains and / or oxyalkylene chains between two Amino groups, the guanidine derivatives using a product of the polycondensation of a guanidine acid addition salt with diamines which contain polyalkylene chains and / or polyoxyalkylene chains between two amino groups. "EP 1 280 766 B1, claim 1. Particularly preferred are a poly (hexamethyleneguanidinium ) Salt and / or poly [2- (2-ethoxy) ethoxyethyl] guanidinium salt Akacid and Akacid Plus are preferred polymeric guanidines according to the present invention.

A preferred embodiment of the composition according to the invention is characterized in that a polymeric guanidine is provided which contains an alkylenediamine and the oxyalkylenediamine in a molar ratio between 4: 1 and 1: 4. The amino groups of alkylenediamine and / or the Oxyalkylendiamins are preferably terminal, wherein for producing the polymeric guanidine as alkylenediamine a compound of general formula NH2 primarily (CH2) _nN is provided H2, in which an integer between 2 and 10, in particular 6 , is. For the preparation of the polymeric guanidine, a compound of the general formula NH _{2 [(} CH _{2) 2} O)] _{m (} CH _{2) 2} NH ₂ may be provided as oxyalkylenediamine, in which an integer between 2 and 5, in particular 2.

Preferred polymeric guanidines may be selected from polyhexamethyleneguanidine; Poly [2- (2-ethoxy) ethoxyethyl] guanidine (Akacid, [374572-91-5]); Polytriethylenglykolguanidin; Polyethylenglykolguanidin; Polyoxypropylenguanidin; Polyoxyethylene guanidine or mixture of poly (hexamethyleneguanidinium chloride) and poly [2- (2-ethoxy) ethoxyethyl) guanidinium chloride] (Akacid Plus), especially a 3: 1 mixture.

Most preferably, the polymeric guanidine is a polyalkylene guanidine, especially a polyoxyalkylene guanidine. "Alkylene" may be a C1-C8 alkyl, preferably a C2-C6 alkyl such as ethyl, propyl, butyl, methylpropyl, pentyl, branched or unbranched, which is preferred in all uses of the term "alkylene" or "alkyl" herein.

Other preferred polymeric guanidines which are well suited for the present invention are described in WO 2014/113835 A1 and WO 2016/015081 A1. Such polymeric guanidines (also called "polyguanidine") may correspond to the formula (I), (II) or (III)

worin Ri entweder für ein aromatisches Ringsystem mit zumindest einem aromatischen Ring, das gegebenenfalls ein oder mehrere Heteroatome, ausgewählt aus 0, N und S enthält und das gegebenenfalls mit einer oder zwei Vinylgruppen substituiert ist, oder für Ethylen steht, oder das eine durch Ringschluss unter Eliminierung eines Guanidins erhaltene zyklische Struktur aufweist. Beispiele für RI sind Benzene (vorzugsweise para- oder meta-stellig eingebunden) , Pyridin (vorzugsweise and den beiden C-Atomen benachbart zum N eingebunden) , Divenylbenzol, Biphenyl (vorzugsweise jeweils beide Benzene para-stellig eingebunden), 1, 3-Bis ( (E) -2- vinyl) benzol, Furan, Pyrrol, Thiophen, Fluoren, Ethylen (vorzugsweise cis-stellig eingebunden) . Derartige polymere Guanidine sind in WO 2016/015081 Al beschrieben.

wherein Ri is either an aromatic ring system having at least one aromatic ring optionally containing one or more heteroatoms selected from O, N and S and which is optionally substituted with one or two vinyl groups, or is ethylene, or the one by ring closure Elimination of a guanidine has obtained cyclic structure. Examples of R 1 are benzenes (preferably para- or meta-digit embedded), pyridine (preferably attached to the two carbon atoms adjacent to the N), divinylbenzene, biphenyl (preferably both benzene linked in a para-position), 1, 3-bis ((E) -2-vinyl) benzene, furan, pyrrole, thiophene, fluorene, ethylene (preferably cis-linked). Such polymeric guanidines are described in WO 2016/015081 A1.

Polymeric guanidines may also contain the compound of formula (IV)

worin

wherein

X from NH ₂ aminoguanidino and 1 3-diaminoguanidino is selected;

Y is selected from -H and -R _I -NH ₂ ; or X and Y together represent a chemical bond to give a cyclic structure;

 Ri is selected from divalent organic radicals having 2 to 20 carbon atoms in which one or more carbon atoms are optionally replaced by 0 or N; a and b are each 0 or 1,

where a + b is not equal to 2, if no 1, 3-Diaminoguanidin- units are included;

R _{2 is selected} from -H and -NH ₂ ,

wherein R _{2 is -NH 2} when a + b = 0,

R _{2 is} H or -NH ₂ when a + b = 1 and

R _{2 -} H is when a + b = 2; and n is greater than or equal to 2;

or a salt of it. Such polymeric guanidines are in WO

2014/113835 Al described.

In the formulas (I) to (IV), n corresponds to a plurality, e.g. to achieve the above molar masses of the polymer. For example, n can be 3 to 200.

Preferably, the guanidine is a guanidinium salt, preferably selected from a halide, preferably a chloride; Phosphate, preferably one

Dihydrogen phosphate; Carbonate; Nitrate; sorbate; Acetate, preferably hydroacetate; gluconate; Citrate; Silicate; etc. This also applies to the polymeric guanidines. The polymeric guanidine of the present invention may be a polyguanidine salt. These compounds with salting partners (counterions), e.g. Halide, phosphate, etc. are e.g. described in AT 411060 B.

Preferably, the average molecular weight of the polymeric guanidine is 200 Da to 10,000 Da, preferably 500 Da to 3,000 Da. For example, the polymeric guanidine may be provided with at least 3 guanidine residues. The polymers of these sizes can be obtained by nanofiltration through membranes become. For nanofiltration, filters with corresponding pore sizes can be used for the permeability of the desired molecular weights. Filtrates (to remove larger polymers) or the residue (to remove the smaller polymers) can be further used to obtain the desired polymer. The desired, preferred polymeric guanidines have improved toxicology. In particular, the elimination of short-chain oligomers and monomers, as well as the elimination of the entrained by the synthesis residues of the diamines is a major focus. Accordingly, monomeric starting materials (guanidines) and oligomers or polymers of guanidine having a molecular weight of 250 Da or smaller, or even 400 Da or smaller, are advantageously removed.

For the treatment of fruits and vegetables, a composition containing 0.025-0.4% by weight, in particular 0.04-0.15% by weight, of polymeric guanidine is particularly effective. Furthermore, it can be provided that the composition 0.5 to 5 wt.%.

Polyaminosaccharide, in particular chitosan contains. As a result, a good film-forming property can be achieved. A particularly effective treatment can be achieved with a composition according to the following formulation.

Polymeric guanine: 0.025-0.15% by weight

 Chitosan: 0.5 to 5% by weight

 - water balance to 100% by weight

 (% By weight based on the total amount of the composition)

The invention is illustrated by way of example with reference to the following examples and figures, without limiting the general inventive idea:

Fig. 1 shows oranges treated with an exemplary composition after storage Fig. 2 shows untreated oranges which were stored simultaneously with the oranges of Fig. 3.

Fig. 3 shows apples treated with an exemplary composition after storage.

Fig. 4 shows untreated apples stored simultaneously with the apples of Fig. 1.

Example 1: Preparation of a polymeric guanidine (e.g., Akacid Plus)

The formulations are based on active ingredients of the group of polyguanidines (Akacid, described in Kratzer et al., Antibiotika Monitor 1/2/2006, Buxbaum et al., Journal of Antimicrobial Chemotherapy (2006) 58, 193-197, WO 01/85676

al; WO 2006/047800 Al; WO 2008/080184 A2; WO 2013/064161 A1). The preparation of Akacid Plus is described in particular in WO 2006/047800 (incorporated herein by reference). The starting substances triethylene glycol diamine, hexamethylene diamine and guanidine hydrochloride were reacted together in one process. In the present case, a 3: 1 mixture of polyhexamethylene guanidinium chloride and poly [2- (ethoxy) ethoxyethyl] guanidinium chloride was used. These polymeric guanidine compounds show an excellent antimicrobial profile and are also able to impart stable formulations with difficult-to-mix substances without solubilizers from the group of polyethoxylated nonionic compounds.

Example 2: Preparation of Exemplary Composition

An exemplary composition was created by mixing the following components: Akacid Plus: 0.05 wt

Chitosan (deacetylation degree of 85%): 1% by weight

Water: balance to 100% by weight

The procedure was as follows:

 Akacid Plus was taken up in water, then an aqueous solution of chitosan was added with constant stirring.

Example 3: Comparative Experiments Oranges

Figures 1 and 2 show the effect of the exemplary composition on harvested oranges. Fig. 1 shows the test group with 10 oranges, Fig. 2 shows the control group with also 10 oranges.

 The oranges of both groups were inoculated after harvest with Penicillinum digitatum.

 The test group was treated after harvest with the exemplary composition (4000 ppm). The control group was not treated further.

 Subsequently, the oranges of both groups were stored under the same conditions for 7 days.

Fig. 1 shows that in the test group, none of the oranges had a fungal infection.

 Fig. 2 shows that in the control group all oranges showed a strong fungal attack. Seven oranges were completely covered by a fungus coating. The remaining three oranges were largely covered by a fungus layer.

 For the oranges of the test groups, no difference to the freshly harvested state was evident.

 The orange of the control group, however, were no longer suitable for consumption due to the fungal infestation.

The oranges of the test group thus had a significantly higher storage life. Example 4: Comparative experiments Apples

Figures 3 and 4 show the effect of the exemplary composition on harvested apples. Fig. 3 shows the test group with 10 apples, Fig. 2 shows the control group with also 10 apples.

 The apples of both groups were vaccinated after harvest with Botrytis cinerea, the causative agent of apple disease. The test group was additionally treated with the exemplary composition (2000 ppm).

 Subsequently, the apples of both groups were stored under the same conditions for 10 days.

 The apples of the test group (Figure 3) had no changes compared to the freshly harvested state.

 In the control group (Figure 4), clear signs of disease were evident. Eight apples were almost completely covered in putrefaction and shriveled. An apple had at least a large foul place. Another apple had only a minimal impairment.

 The apples of the test group were optically indistinguishable from freshly harvested apples after storage for 10 days. In the control group, almost all apples were inedible.

The treated apples therefore had a significantly higher storage life.

Example 5 Comparative Experiments Pears

The durability extension was tested by the use of exemplary solutions according to the invention of 10% Akacid Plus and chitosan in 2 varieties of Dangshan Su pear after harvest. Chitosan with a degree of deacetylation of 85% was used.

The aim was to determine the effect of the extension of the Shelf life with different concentrations of Akacid Plus 10% and chitosan.

Dangshan su pear pears were used. The test material came from 10-year-old pear trees, which had no infestation with insects, microorganisms or other damage. The pears were of largely the same maturity and size. The average weight was 147.74 g, the average hardness was 2.79 kg / cm ² and the average soluble solids content was 10.7.

The Dangshan Su pears were examined at normal room temperature compared to cold storage conditions. The test conditions were five test arrangements for storage at room temperature and in cold storage conditions (0-2 C °).

Different concentrations of Akacid Plus were used. Dilutions of 250, 500, 1000 and 1500 ppm were investigated and compared to pure water. The five approaches were repeated four times.

To each batch was added 1000 ml of 1% chitosan solution. Storage at room temperature was examined for 30 days. Controls were performed on the 10th, 20th and 30th day after storage.

For the cold storage conditions, a check was carried out on the shelf every 5th day. Three additional checks every 15 days were also made. The experiment was carried out for a total of 45 days. In each case weight, hardness, soluble solids and acid content were investigated.

The fruits of the test groups were initially held in the test solution for 5 minutes and then dried naturally for 24 hours. Each fruit was then stored on the bottom of a plastic drum (26 x 35 x 43 m) Closure was sealed with petroleum jelly. The fruits were stored under different temperature conditions.

Table 1 shows the evolution of strength during storage. The decrease in strength could be observed in all approaches, regardless of cool storage conditions or room temperature, or treatment with or without addition.

Table 1 :

Table 2 shows the content of soluble solids. Soluble solids content in the pears was significantly greater at day 30 in the treated groups. Even under the cold storage conditions, a higher content was detectable. The different Akacid Plus concentrations of the compositions were associated with a 5% higher soluble solids content per stage. Table 2:

 sojuble solid

Tab. 3 shows the content of titratable acids. For the titratable acid content, there was a significant difference between the content of the pears treated with the test solution and the control group. The difference between room temperature and cold storage was not as pronounced as compared to the test group.

Table 3:

Tab. 4 zeigt die Auswertung der bei Raumtemperatur gelagerten Birnen . Tabelle 4 : Unit; A 10-2%

Tab. 4 shows the evaluation of pears stored at room temperature. Table 4:

Die verwendete Akacid Plus - Chitosan Mischung hatte einen eindeutigen Frischhalteeffekt auf die Birnen. Dieser war wesentlich ausgepägter als der Effekt, der nur durch die kühleren Lagerbedingungen zu erzielen war. Table 5 shows the evaluation of the pears stored in cold storage conditions.

The used Akacid Plus - Chitosan mixture had a clear freshness effect on the pears. This was much more elaborate than the effect that could be achieved only by the cooler storage conditions.

The concentration that showed the best result in terms of freshness was a 500 ppm Akacid Plus dilution. It has been shown that treating the pears with an Akacid Plus chitosan solution has resulted in reduced aging, a better appearance and better inner quality of the pears.

Claims

Claims: A liquid composition containing at least one polymeric guanidine and at least one wetting agent dissolved in an inorganic solvent. 2. Composition according to claim 1, characterized in that the wetting agent is a polyaminosaccharide, in particular chitosan. 3. Composition according to claim 1 or 2, characterized in that the inorganic solvent is water. Composition according to any one of Claims 1 to 3, characterized in that the polymeric guanidine is a polyalkylene guanidine or a polyoxyalkylene guanidine. 5. The composition according to any one of claims 1 to 4, characterized in that the polymeric guanidine is a polymeric condensation product obtainable by reacting guanidine or a salt thereof, with an alkylenediamine and / or an oxyalkylenediamine, in particular with an alkylenediamine and / or a Oxyalkylenediamine terminated with amino groups. 6. The composition according to any one of claims 1 to 5, characterized in that the polymeric guanidine is obtainable by a reaction of guanidine or a salt thereof, with an alkylenediamine and an oxyalkylenediamine, wherein the alkylenediamine and the oxyalkylenediamine in the molar ratio between 4: 1 and 1: 4 are used. 7. A composition according to any one of claims 1 to 6, characterized in that as oxyalkylene diamine triethylene glycol diamine (relative molecular mass: 148) Polyoxypropylenediamine (relative molecular weight: 230) and / or polyoxyethylenediamine (relative molecular mass: 600) is provided. 8. The composition according to any one of claims 1 to 7, characterized in that the polymeric guanidine is obtainable by a reaction of guanidine hydrochloride with triethylene glycol diamine or is obtainable by a reaction of guanidine hydrochloride with hexamethylenediamine and with triethylene glycol diamine. Composition according to any one of Claims 1 to 8, characterized in that the polymeric guanidine is chosen from polyhexamethyleneguanidine; Poly [2- (2-ethoxy) ethoxyethyl] guanidine (Akacid, [374572-91-5]); Polytriethylenglykolguanidin; Polyethylenglykolguanidin; Polyoxypropylenguanidin; Polyoxyethylene guanidine or a mixture, especially a 3: 1 mixture, of poly (hexamethylene guanidinium chloride) and poly [2- (2-ethoxy) ethoxyethyl) guanidinium chloride] (Akacid Plus, [905929-86-4]). Composition according to any one of Claims 1 to 9, characterized in that the guanidine is a guanidinium salt, preferably selected from a halide, preferably a chloride; Phosphate, preferably a dihydrogen phosphate; Carbonate; Nitrate; sorbate; Acetate, preferably hydroacetate; gluconate; Citrate; Silicate. 11. The composition according to any one of claims 1 to 10, characterized in that the average molecular weight of the polymeric guanidine 200 Da to 10,000 Da, preferably 500 Da to 3000 Da. 12. The composition according to any one of claims 1 to 11, characterized in that the composition 0.025 to 0.4 wt.%, In particular 0.04 to 0.15 wt.%, Polymeric Guanidine contains, based on the total amount of the composition. 13. The composition according to any one of claims 1 to 12, characterized in that the composition contains 0.5 to 5 wt.% Polyaminosaccharide, in particular chitosan, based on the total amount of the composition. Composition according to any one of Claims 1 to 13, characterized in that the composition contains or consists of the following components: Polymeric guanine: 0.025 - 0.15% by weight  Chitosan: 0.5 - 5 wt. %  Water balance to 100% by weight  (% By weight based on the total amount of the composition) Use of the composition according to any one of claims 1 to 14 for increasing the shelf life of harvested fruits and vegetables and / or as crop protection agents against unwanted microorganisms on the surface of harvested fruits and vegetables. 16. A method for increasing the shelf life of harvested fruits and vegetables and / or controlling unwanted microorganisms by exposing the surface of harvested fruits and vegetables to a composition according to any one of claims 1 to 14. 17. Use according to claim 15 or method according to claim 16, characterized in that the harvested fruit or vegetables is sprayed with the composition, coated or atomized or dipped in the composition and held therein for a given residence time.