AU2016287365B2

AU2016287365B2 - Coating compositions made of shellac and emulsifier, and methods for coating food products

Info

Publication number: AU2016287365B2
Application number: AU2016287365A
Authority: AU
Inventors: Alberto Sardo
Original assignee: Xeda International SA
Current assignee: Xeda International SA
Priority date: 2015-06-29
Filing date: 2016-06-29
Publication date: 2020-02-27
Anticipated expiration: 2036-06-29
Also published as: NZ738122A; FR3037774A1; BR112017028097B1; AU2016287365A1; BR112017028097A2; EA201792647A1; WO2017001502A1; EA033545B1

Abstract

The present invention relates to novel compositions for coating food products, made of shellac, solvent, emulsifier such as polysorbate and optionally water with a content of less than 8 wt.%, and to the uses thereof for coating food products.

Description

SHELLAC- AND EMULSIFIER-BASED COATING COMPOSITIONS AND FOOD PRODUCT COATING METHODS

Fresh foods such as fruit and vegetables, citrus fruits in particular, are generally coated before marketing to improve the preservation and appearance thereof for consumers. Food waxes are especially used to coat citrus fruit. The use thereof is limited however on account of their low solubility in ethanol, a solvent that is considered food safe. WO 2010/031929 describes coating compositions containing a filmogenic agent selected from among waxes, resins, shellac or the esters of abietic acid in a solvent for application via drenching under atmosphere pressure or by immersion. More particularly, shellac-based compositions in ethyl alcohol, optionally in the presence of ammonia, are described. Nonetheless, it has been observed that these compositions are not fully satisfactory in terms of ageing of the coated fruit and vegetables. There remains to be provided an improved shellac-based composition that can allow the ensured improved ageing of coated fruit and vegetables. Documents EP 2 468 107, CN 102 630 744, KR 101 419 385 and CN 102 823 644 describe food product coating compositions containing shellac and non-ionic emulsifier in particular of polysorbate type. However, the compositions described in these three first documents do not exhibit satisfactory drying properties and are therefore not suitable for the treatment of fruit and vegetables under industrial conditions. The last document describes compositions in the form of creams with which it is difficult to obtain homogeneous distribution over the surface of the food products to be treated.

Therefore, a first subject of the invention concerns a coating composition for food products, in the form of a solution, said composition comprising shellac, an organic solvent, at least one non-ionic emulsifier and optionally water, on the understanding that when the composition contains water it is contained in an amount of 8 % by weight or lower.

In the present invention the term « solution » designates a homogeneous mixture in liquid form of two or more constituents. The « solutions )) of the invention therefore differ from pastes, waxes, creams or emulsions. The compositions of the invention are therefore in the form of clear solutions.

According to one embodiment, the present invention concerns food product coating compositions comprising: - shellac; - a solvent; and - at least one non-ionic emulsfier of polysorbate type As non-ionic surfactant that can be used in the invention, mention can be made of the condensation product of an aliphatic fatty alcohol, preferably C1-C22 with a C2-C3 alkylene oxide. The C2-C3 alkylene oxide may be ethylene oxide, propylene oxide or else a mixture of ethylene oxide and propylene oxide in any proportion. One example of said surfactant is the product of lauryl alcohol with ethylene oxide. The condensation product of a fatty acid with polyethoxylated sorbitan can also be cited, such as polysorbates. Mention can also be made of the product derived from the condensation of polyethoxylated sorbitan with oleic acid, called Tween 80, or polysorbate 80 - IUPAC name polyoxyethylene (20) sorbitan monooleate. According to one preferred embodiment, the emulsifier is Tween 80. According to one embodiment, the content of the non-ionic emulsifier is between 0.25 and 5 %, more particularly between 1 and 4 %, further particularly about 2 % by weight of said compositions.

Shellac is also called E904. It is commercially available and in particular from SSB STROEVERSCHELLAKBREMEN. According to one embodiment, the compositions generally comprise up to 50 % by weight of shellac, in particular from 0.25 to 35 %, more particularly from 1 to 35 % by weight.

Advantageously, the solvent is selected from among an alcohol or light alkane, particularlya C2-C10 alcohol or C6-C10 alcohol. Particular mention can be made of ethyl alcohol, isopropyl alcohol or hexane. Preferably, the solvent is an alcohol and more preferably ethyl or isopropyl alcohol. According to one embodiment, the solvent is ethyl alcohol. The use of alcohol as solvent is particularly advantageous in that it has disinfectant even sterilising action on the food product against contaminations present on the surface thereof. Ethanol is particularly cited having regard to its approval for food use.

When a water-soluble solvent is used such as alcohols, the coating composition may also comprise a base. The solvent generally represents 15 to 99 % by weight of the composition, preferably 50 % to 95 % by weight of the composition.

The compositions of the invention may optionally contain water. The compositions of the invention comprise less than 8 % by weight of water and preferably less than 5% by weight of water relativeto the total weight of the composition. The compositions of the invention therefore generally have a water content lower than that of the azeotrope described by the phase diagram of a water/alcohol mixture, thereby allowing better drying of the compositions after application. The water may derive from the base if it is a diluted aqueous solution.

According to one embodiment, said compositions of the invention further comprise a base. The adding of a base to the coating composition comprising a water-soluble solvent allows improved solubility of the resin in the solvent, so that the coating is of satisfactory quality even in the presence of residual water e.g. when water originating from ambient humidity etc., condenses on the food products to be treated. As base, particular mention can be made of any organic or mineral base. Preferably, the base is selected from among ammonia, sodium hydroxide, potassium hydroxide or amines such diethanolamine or morpholine.

The base may be in the form of an aqueous solution: in this case the compositions comprise water. In general, the base is between 0 and 10 % by weight of the coating composition, preferably between 0.1 and 5 %, more preferably between 1 and 5 %.

According to one embodiment, the compositions of the invention comprise: - between 0.25 and 50 % by weight of shellac; - between 15 % and 99 % by weight of solvent; and - between 0 and 10 % by weight of base; and - between 0.25 and 5 % by weight of non-ionic emulsifier.

According to one more particular embodiment, the compositions comprise: - between 1 and 35 % by weight of shellac; - between 15 and 95 % by weight of ethyl alcohol;

- between 0.25 and 5 % of Tween 80; - between 0.1 and 10 % of base.

The compositions of the invention may also comprise monopropyleneglycol. In general, the compositions of the invention may comprise between 0.5 and 5 % by weight of monopropylene glycol. The coating composition may also comprise one or more terpenes, selected in particular from among non-oxygen-containing terpenes such as pinenes and limonene, or eugenol, in general between 0 and 50 % by weight of terpene(s). The compositions of the invention are prepared by mixing the ingredients under agitation. By food product is meant any food such as fruit, vegetables, cheese or eggs usually coated for preservation. Particular preference is for fruit and vegetables. The expression ( fruit or vegetables » preferably refers to the treatment of citrus fruit such as oranges, lemons, clementines, grapefruit, mandarins or apples or any other fruit or vegetable usually coated for preservation and/or marketing.

The compositions of the invention can be applied by drenching or spraying onto the food products to be coated, arranged on a conveyor. Said drenching is performed at atmospheric pressure without a jet, spray or atomizer. According to the invention, drenching is efficiently obtained using the overflow of the feed tank of said composition, with over-spilling of the composition which falls under gravity onto the food products positioned on a first zone of the conveyor, underneath the overflow zone, or via drip flow by means of perforations made in the feed tank. Alternatively, the composition may also be applied by spraying using a jet, spray or atomizer. According to another embodiment, said composition may also be applied by dipping the products to be coated into a bath containing the composition. In general, the application of the composition is performed after harvesting and before marketing of the food products, in particular at ambient temperature. The compositions can be applied in a single time or several times. According to one embodiment, the compositions are applied to the food products after they have been previously dried. All the percentages indicated herein are weight percentages. The coating compositions of the invention are intended to be applied pure, in particular without prior dilution.

The amount of composition to be applied is dependent on the type of food products concerned and on the chosen application mode. In general, between 1 and 10 L of composition are applied per tonne of food products, in particular between 2 and 5 L/T. The solvent of the compositions is generally evaporated in air via suction followed by extraction or absorption.

The composition of the invention can be applied by any known means, in particular with the method and device described in application WO 2010/031929.

Figures: Figure 1 illustrates the impact of the presence of Tween 80 in the composition on the firmness of treated apples. Figure 2 illustrates the impact of the presence of Tween 80 in the composition on weight loss of the treated apples.

The following examples are given to illustrate the invention and are nonlimiting.

Example 1: A composition of the invention is prepared in the following manner: The following are mixed under agitation: - 86.5 g ethyl alcohol; - 10 g shellac; - 0.5 g Tween80; - 2.5 g monopropylene glycol, - 0.5 g 20 % alkali. A clear solution is obtained.

Example 2: The composition in Example 1 (hereafter calledXedasol L2) was applied after harvesting by dipping apples. For comparison, a composition called Xedasol L, devoid of Tween 80, was also applied. The composition of the solutions was the following:

XedasolL XedasolL2 ethyl alcohol 15 to 95% 86.5% shellac 1 to 35% 10%

Monopropylene glycol 0.5 to 5% 2.5% 20% alkali 0.1 to 10% 0.5% Tween 80 0% 0.5%

The study conditions and results are detailed below.

1. Plant material The test was conducted on harvested apples ofGoldrush variety. The fruit came from trees in lot P26 of the La Morinibre field station.

2. Experimental procedure The apples were randomized in crates containing 50 apples after harvesting. 4 repeats of 50 apples were used per modality.

3. Treatment modalities 4 treatment modalities were used:

Applied Modality Treatment Application modality dose dose TO XedasolL Dipping, drying in ambient air 5Lt/tonne On harvesting T1 XedasolL2 Dipping, drying in ambient air 5Lt/tonne T2 On leaving XedasolL Dipping, drying in ambient air 5Lt/tonne T3 CA storageat XedasolL2 Dipping, drying in ambient air 5Lt/tonne 2.50C

The treatments were performed: TO and T1: Two weeks after harvesting, followed by storage in a controlled atmosphere at 2.5°C. T2 and T3: On leaving storage about 4 months afterwards, then stored in normal cold storage for 16 days at 3°C (simulated removal from storage).

4. Storage conditions The fruit was stored in a controlled atmosphere at a temperature of 2.5°C, 1.5% C02, 2.5% 02 for about 4 months, then 16 days in normal cold storage at 3°C.

5. Measured parameters allowing interpretation of results Measurement of weight loss: The weight of the fruit was recorded before and after treatment, to evaluate loss of weight of the fruit.

Measurement of ethylene release: Ethylene release was measured on leaving storage to evaluate the impact of the wax on fruit respiration. Variance analysis was performed using Statbox software following C.E.B. method N° 225. If a significant difference was observed, a Newman Keulstest was conducted to classify the products among themselves.

« Quality analyses performed on date of harvesting

Starch Basic colour Firmness in kg/cm2 IR in % Brix Malic acid in g/l (scale 1to 10) (Golden code 1to 8)Fimesngc 5.7 5.2 8.3 14.1 8.2

Ethylene measurements on removal from CA storage

After storage for 24 hours and 7 days at 18°C, release of ethylene was measured for each modality XedasolL XedasolL2 XedasolL XedasolL2 XedasolL XedasolL2 XedasolL XedasolL2 harvest harvest CA removal CA removal harvest harvest CA removal CA removal

at+24 hours at20°C at+7 days at20°C

Ethylene production in 12.8 8.67 5.49 4.71 48.95 32.61 33.1 22.03 micro L/h/kg

The results show that the modalities treated with the wax formulationXedasol L2 on harvesting and on removal from storage release less ethylene comparedwith the batches treated with Xedasol L.

Impact of the composition on apple firmness

The results are illustrated in Figure 1:

The Xedasol L2 wax formulation comprising a surfactant improves the maintaining of firmness, after a shelf life period of 24 hours and 7 days.

Impact of composition on weight loss

The results are illustrated in Figure 2. The Xedasol L2 formulation comprising a surfactant applied at the time of harvesting allows improved control over weight loss during storage in a controlled atmosphere at 2.5°C. A reduction in the order of 29 % is observed in comparison with the modality waxed with XEDASOL L at the time of harvesting.

When applied on removal from storage, the difference is smaller. Thereduction in weight loss is 15 % over a period of 14 days under normal cold storage at 32°C. Statistical analysis does not differentiate between the waxed modalities on leaving storage.

CONCLUSION

The above crops show a significant effect when Xedasol L2 wax comprising a surfactant is applied at the time of harvesting. The modification of the formulation (addition of surfactants, here Tween 80) has a beneficial effect. Statistically, the fruit is firmer, weight loss is much reduced. This effect is less significant on the modalities treated on removal from controlled atmosphere storage; weight loss and firmness chiefly occur during the storage period.

Example 3: The apples coated with the Xedasol L and Xedasol L2 solutions of Example 2 were also compared for shine and humidity resistance. The solutions were applied at the same dose and using the same method as in Example 2.

3.1 Evaluation of shine after waxing and drying of fruit: Shine was evaluated visually and given a shine score of 0 to 10 (10= maximum shine). The following results were obtained: Shine score XedasolL 8.5 XedasolL2 9

3.2 Evaluation of resistance to humidity: 24h after application of Xedasol L and Xedasol L2, the fruit was immersed in water for 1 minute and then dried in ambient air. After a few hours, shine was evaluated visually and given a score of 0 to 10 (10= maximum shine) and the presence of any white marks was detected, such marking indicating humidity-related degradation of waxing. The following results were obtained:

shine Presence of white marks XedasolL 6 Yes XedasolL2 8.5 No

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1.- Composition for coating food products, in the form of a solution and comprising: - shellac; - an organic solvent; - at least one non-ionic emulsifier of polysorbate type; and - optionally water, such that said composition comprises less than 8 % by weight of water, wherein said emulsifier is Tween 80, and said organic solvent is ethyl alcohol.

2.- The composition according to claim 1 wherein said solvent represents 15 % to 99 % by weight of the composition.

3.- The composition according to claim 1 or 2 wherein it further comprises a base.

4.- The composition according to claim 3 wherein the base is selected from among ammonia, sodium hydroxide, potassium hydroxide, and amines such as diethanolamine or morpholine.

5. The composition according to any one of the preceding claims wherein it comprises between 0.25 and 5 weight % of Tween 80.

6.- The composition according to any one of the preceding claims wherein it comprises: - between 1 % and 35 % by weight of shellac; - between 0.25 and 5% by weight of Tween 80; - between 15 % and 95 % by weight of ethyl alcohol; and - between 0.1 and 10% by weight of base; - and optionally between 0.5 and 5 % by weight of monopropylene glycol.

7.- Method for preparing a composition according to any one of the preceding claims, comprising the mixing of the ingredients under agitation.

8.- Method for coating food products, comprising the application of a composition according to any one of claims 1 to 6 by drenching, immersion or spraying.

9.- The method according to claim 8 wherein between 1 and 10 L of the composition according to any one of claims 1 to 6 is applied per tonne of food products.

10.- The method according to one of claims 7 and 8 wherein said food products are fruit and vegetables.