Cocoa husks, a by-product of cocoa processing, may offer an alternative, environmentally friendly, and cost-efficient source of pectin for food, suggests a new study.
If research can build on the results of this preliminary study, published in the journal Food Chemistry, the cocoa waste-product could offer an alternative to sourcing the ingredient from citrus peel and apple pomace. Researchers from the Institute of Material Science and Chemical Engineering at Torino Polytechnic report that mincing the husks for one hour and then extraction under acidic condition (pH 2.5) produced the best yields of about eight per cent.
The ingredient, with worldwide production estimated at 35,000 tonnes a year, is currently widely used as gelling agents in jams, confectionary, and bakery fillings, and stabilisers in yoghurts and milk drinks. The research taps into the growing trend for alternative and novel sources of pectin, highlighted by an increasing number of studies looking at extracting pectin from sources such as sugar beet, mango, pumpkin and squash.
The functionality of pectin is dictated by the chemical fine structure, and the majority of the pectin used currently comes from citrus peel and apple pomace. Other sources of the ingredient have remained largely unexploited because of certain undesirable structural properties. "Recently, non-traditional pectin sources have been investigated," added the researchers.
"Pectins have been extracted from various food industry by-products and, considering that food processing is characterised by large amounts of waste material, by this way the extraction process could represent an efficient and environmental friendly matter recovery for the production of functional compounds." The researchers extracted pectin from the whole or minced husks of cocoa from Ghana and Venezuela under a variety of pH levels and extraction periods.
They stated that the hot acid extraction, as is usually applied for the extraction of commercial pectin, was also the most suitable for the recovery of pectin from cocoa husks. "Because some problems arose during extractions at low pH values (1.5, 1.0), for example the probable presence of tannins, more investigations into the optimization of the extraction parameters are highly desirable," they wrote.
"Further investigations need also to be directed at the characterisation of the extracted samples in order to reveal possible undesirable aspects and to correct them through chemical modifications during extraction." Researchers from Denmark and England recently highlighted the possibilities of this ingredient and proposed that 'designer' pectin will become increasingly common in the future (Trends in Food Science & Technology, Vol. 17, pp. 97-104).
Source: Food Chemistry (Elsevier) Published on-line ahead of print, doi:10.1016/j.foodchem.2007.09.006 "Extraction and characterization of pectins from cocoa husks: A preliminary study"
Authors: C. Mollea, F. Chiampo and R. Conti