TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process for the purification of polyphenols from a starting material. In particular the present invention relates to a fraction enriched in polyphenols, in particular chlorogenic acids (CGA's) obtainable from a plant material, wherein the isomer balance of the enriched fraction is substantially maintained compared to the starting material.
BACKGROUND OF THE INVENTION
An important property of beverages, such as coffee is persistent foam also referred to as “crema” and intense aroma which are considered important quality criteria. The volume, texture, finesse, color and stability of the crema are distinctive characteristics appealing to the consumer. Crema results from the extraction of surface active coffee components that coat and stabilize the gas bubbles created by blasting the tamped espresso coffee matrix with pressurized heated water.
Coffee aroma is also an important property because the intensity of the coffee aroma is the first sensoric experience that meets the consumer. When smelling coffee, the aroma can help you evaluate the coffee flavor and the brightness of the coffee. During roasting many aromatic compounds are formed or liberated from the coffee bean matrix and affect the experience (aroma and flavor) of the coffee. One of the most important precursor of aromatic compounds are chlorogenic acids, in particular caffeoyl quinic acid.
Thus, there has been an interest to isolate a polyphenol enriched fraction from many different kind of plant materials, e.g. berries, grapes, citrus, vegetables, cereals, herbs, tea, coffee, cocoa. In particular there has been an interest to isolate a polyphenol fraction enriched in chlorogenic acid compounds and which has an isomeric balance of the chlorogenic acid compounds that resemples the original plant material, in order to spike food and beverage products with e.g. aroma and flavor.
Furthermore, polyphenols have been reported to have antimicrobial, antiviral, antimutagenic, anticarcinogenic, antiproliferative and vasodilatory effects. Polyphenols may have antibacterial activity which may be useful in the combat of tooth decay caused by Streptococcus mutans. Polyphenols are listed as nootropics purported to improve mental functions such as cognition, memory, intelligence, motivation, attention and concentration.
However, strengthening of the rules for health claim in food legislation makes it compulsory to ensure a consistent level in the active ingredient as well as to refer to scientific evidence obtained on the manufactured products.
Thus, there is a need for a process for providing a polyphenol enriched fraction, especially comprising chlorogenic acids (CGA's) where the chlorogenic acid balance resembles the chlorogenic acid balance originally present in the plant material. The enriched fraction may subsequently be used to ensure a constant level in active ingredient of food product as well as in intervention studies to demonstrate the cause and effect relationship between the intake of polyphenols, such as from coffee, and a given claimed effect.
Thus, there is a need in the industry to provide a process for providing a fraction enriched in polyphenols, in particular chlorogenic acid, having the most authentic characteristics relative to the plant material it originates from which may be used to enhance the properties of a food product or a beverage.
SUMMARY OF THE INVENTION
Accordingly, the present invention describes a novel process for the purification of polyphenols where the polyphenolic balance is maintained or substantially maintained. Furthermore, the process of the present invention may result in a limited or no formation of derivatives formed during the process e.g. ethylesters of the polyphenols. Ethylesters are undesirable because they do not have the same properties as the native polyphenols naturally occurring in the plant material. In addition, ethylesters change the polyphenol balance of the enriched fraction relative to the original product.
Thus, one aspect of the invention relates to a process for providing a fraction enriched in polyphenols from a starting material, the process comprises the steps of:
(i) solubilizing the starting material in an aqueous solvent;
(ii) adjusting pH to below pH 3;
(iii) contacting the starting material with a chromatographic resin;
(iv) desorbing the polyphenols from the chromatographic resin to provide an eluate comprising the polyphenols;
(v) adjusting pH of the eluate to above pH 3.5; and
(vi) separating the eluate from the eluted polyphenols to obtain the fraction enriched in polyphenols.
Another aspect of the present invention relates to a fraction enriched in polyphenols obtainable from the process according to the present invention.
Yet another aspect of the present invention is to provide a food ingredient comprising the fraction enriched in polyphenols according to the present invention.
Still another aspect of the present invention is to provide a food product comprising the fraction enriched in polyphenols according to the invention and/or the food ingredient according to the present invention.
A further aspect relates to the use of the fraction enriched in polyphenols according to the present invention and/or the food ingredient according to the present invention as a precursor for generating aroma, flavor and/or foaming.
Yet another aspect relates to a pharmaceutical composition comprising the fraction enriched in polyphenols according to the present invention and a pharmaceutical acceptable carrier.
… Conversion factors of
chlorogenic acid isomers were determined using pure standards from
Biopurify. Concentrations, expressed in gram per 100 gram, of the other CQA are determined from that of the 5-CQA thanks to this formula …
