Emulsifiers from grape processing by-products

Abstract

A process is described by which the solid waste of grape resulting from processes such as vinification, is treated with hot steam, then is treated with alcoholic solutions, the alcohol being removed, then the oil residues present in the solid residue are removed. The said solid residue is then subjected to aqueous extractions, the aqueous medium is separated from the remaining solids, and this aqueous medium is concentrated. The said material is also described, being capable of emulsifying oil-in-water emulsions and provide stability to colloids.

Claims

1. A process for isolating biopolymer-rich extracts from grape pomace, which comprises said steps: (a) grape pomace is subjected to a steam blanching process, from 0 minutes to 1 hour at 70-90 C., resulting in a blanched material, (b) subjecting said blanched material to extraction by water-ethanol mixtures of an ethanol concentration of 50% to 98% w/w, at temperatures below 70 C., to obtain a dispersed solid, (c) removing the liquid from said dispersed solid as to obtain a solid residue, (d) treating said solid residue with an organic solvent at temperatures from 20 C. to 90 C. and for times from ten minutes and twenty-four hours as to obtain a defatted solid material, (e) extracting said defatted solid material by an aqueous solvent, at temperatures from 20 C. to 90 C. and for times from ten minutes to twenty-four hours, as to obtain a biopolymer-rich liquid extract.

2. A biopolymer-rich solid extract obtained by drying the biopolymer-rich liquid extract of claim 1.

3. A food product comprising the biopolymer-rich liquid extract of claim 1.

4. An emulsion product comprising the biopolymer-rich liquid extract of claim 1.

5. A cosmetic product comprising the biopolymer-rich liquid extract of claim 1.

6. A food ingredient comprising the biopolymer-rich solid extract of claim 2.

7. A food product comprising the biopolymer-rich solid extract of claim 2.

8. An emulsion product comprising the biopolymer-rich solid extract of claim 2.

9. A cosmetic product comprising the biopolymer-rich solid extract of claim 2.

Description

DESCRIPTION OF THE INVENTION

(1) This Invention includes: (i) a process to isolate a material from solid grape-processing waste; (ii) the said material, which is able to act as an emulsifier for the formulation of oil-in-water emulsions.

(2) The process for the manufacture of the material in question is as follows:

(3) Starting material of the present invention is the solid waste obtained after any gape-processing technique, including but not limited to vinification process, henceforth called grape pomace, also referred in various sources as grape marc. This material is subjected to blanching process. During this process the grape pomace is inserted into blanching apparatus, such as a screw-blancher, for zero to tens of minutes, where it is contacted with hot steam. This process is performed in order to denature enzymes that are present to pomace, aiming at increasing the yield of the end product. The material can also be subjected to moisture reduction. Moisture reduction of grape pomace can be achieved via a number of treatments, including but not limited to drying under atmospheric pressure; drying under vacuum; freeze drying; combinations of the above.

(4) Extraction of the exhausted grape-processing waste using ethanol-water mixtures, of a composition ranging from 50% to 98% ethanol. Extraction takes place at temperatures below 70 C. After each extraction process, the solids are separated from the liquid. This can be achieved by a number of processes, including but not limited to filtration; centrifugation; sedimentation; or combinations of the above. This extraction process under ethanol may be repeated from one to nine times, and can be seen as the relevant recycling arrow in FIG. 1 (Drawing). The resulting solid residue is of interest to this process. Residual oil can be conditionally extracted by an appropriate process, including but not limited to Soxhlet extraction. This solid product is to be called exhausted grape waste.

(5) The material of the above treatment is subjected to aqueous extraction. The aqueous extraction solvents used in this process may nonexclusively comprise of potable water; distilled water; de-ionized water; ultra-pure water; doubly or multiply distilled or de-ionized water; or combinations of the above. The pH of the aqueous solvent may be adjusted by the use of buffer solutions of indicative but not limiting concentrations ranging from 0 to 100 mM. These buffer solutions include but are not limited to acetate and phosphate salts. The pH range of the extraction ranges between pH 3 and pH 10. Extraction temperatures can range between 50 C. and 90 C. This extraction step is to be followed by separation of the solid residues from the liquid medium. This can be achieved by a number of processes, including but not limited to filtration; centrifugation; sedimentation; reverse osmosis; microfiltration; nanofiltration; dialysis; or combinations of the above. This extraction process may be repeated from one to five times, and can be seen as the relevant recycling arrow in FIG. 1 (Drawing). The material of interest to this Invention resides in the liquid phase.

(6) The liquid phase produced by the previous stage undergoes processing as to reduce its water content to the desired level. Moisture reduction can be achieved via a number of treatments, including, but not being limited to, drying under atmospheric pressure; rotary evaporation; drying under vacuum; freeze drying; spray drying; reverse osmosis; microfiltration; nanofiltration; dialysis; or combinations of the above. The final material (Grape Waste Emulsifier, GWE) is able to act as emulsifier and/or stabilizer for the production of dispersions such as oil-in-water emulsions. In its dry form, the material resulting from this process is a brittle, fabric-like sticky mass, typically odorless, almost tasteless, and purplish to brownish in color, its overall image depending upon a number of factors including but not limited to grape cultivar; grape age; extraction parameters. The overall process is depicted in the Drawing (FIG. 1).

(7) The material produced by means of the process described above (GWE) is able to act as an emulsifier for the formulation and stabilization of fine dispersions of an oil into an aqueous phase, that is oil-in-water emulsions. That is, upon its dispersion or dissolution in an aqueous solution of an appropriate concentration, pH, temperature and salt content, and upon the subsequent addition of an appropriate amount of a hydrophobic liquid, including but not limited to vegetable oil, olive oil, melted fat, paraffin or hydrocarbon, or combinations of the above, and upon the enforcement of shear fields able to disrupt the oil into small droplets, the material of interest to this Invention can conditionally contribute in providing stability against flocculation, aggregation, coalescence, phase inversion, Ostwald ripening, combinations of the above, or similar destabilization mechanisms.

(8) The stability incurred by the application of GWE manifests as a stable distribution of the droplet sizes or a small increase of the average size of the droplets for a minimum of 24 hours, as compared to the absence of an emulsifier, and within the statistical error of the method used for droplet size measurement. Typical applications include, but are not limited to: 1% w/v of the extract concentration to emulsify an oil-in-water emulsion of oil phase volume fraction of 0.1, in order to produce droplets which can remain relatively stable for a period of at least 1 day.

(9) This invention is effective at low concentrations as an emulsifier at pH values lying between pH 2 and pH 10. The exact range of effectiveness can be narrower or wider than this range, depending on a number of factors such as the cultivar, the condition and composition of the grape waste, and the choice of extraction media and process conditions. This product can conditionally be used as an emulsifier or stabilizer in cosmetic, neutraceutical, pharmaceutical and food products. Under the above, potential applications may include but are not limited to, soups, day creams, desserts, spreads, beverages, dairy products, processed meat products, cured meat products, mayonnaise-type products, salad sauces, dressings, condiments, nutritional supplements, cocoa products, spreads, hand creams, body creams, day creams, night creams, emollient lotions, shampoos, bath formulations, drugs and relevant products.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(10) A brief description of the Drawings presented as FIG. 1 is as follows: The solid waste is blanched; then undergoes alcohol/water extractions, the residue is separated; oil is removed from the residue; the residue undergoes aqueous extractions; the liquid is separated and then concentrated.