The functionality of pectin is dictated by the chemical fine structure, and the majority of the pectins used currently come from citrus peel and apple pomace. Other sources of the ingredient have remained largely unexploited because of certain undesirable structural properties.
"Although the potential stocks of these raw materials enables the main pectin producers (USA, Germany, Denmark) to plan an annual increase of pectin production of approximately 3.8 per cent, searching for new pectin-containing raw materials is an important task of science and industry," wrote the researchers from the Saratov State Agarian Vavilov University and the Moscow State University of Applied Biotechnology.
"Pumpkin pulp seems more promising for pectin production in Russia and it would be appropriate to verify the hydrolysing action of the early used enzyme preparation on this non-traditional pectin-containing raw material," they added.
Researchers from Denmark and England recently highlighted the possibilities of this ingredient and proposed that 'designer' pectins will become increasingly common in the future (Trends in Food Science & Technology, Vol. 17, pp. 97-104).
The ingredient, with worldwide production estimated at 35,000 tonnes a year, is currently widely used as gelling agents in jams, confectionery, and bakery fillings, and stabilisers in yoghurts and milk drinks.
The chemical and enzymatic modification of the pectins occurs after extraction from the plant, and the most industrially important pectinolytic enzymes coming from bacterial sources. This approach has enabled scientists to tailor the pectin according to the required functionality.
The research, published in the journal Food Hydrocolloids and presented last year at the 8th International Hydrocolloids Conference in Norway, enzymatically modified pectin extracted from pumpkin using enzymes cultured from Aspergillus awamori.
The pectin was classified as a high-methoxy pectin with a degree of esterification greater than 50 per cent, which, the authors admit, does not conform with the food industry standard of using pectins with DE greater than 60 per cent.
"It may seem that the biopectin obtained using the enzyme preparation from Aspergillus awamori is not promising for use in food production," they said. "However, this would be a wrong conclusion."
Ptichkina and co-workers point out that the biopectin can form gels with a 60 per cent sucrose solution, making it "possible to use [it] in confectionary and baking jelly-covered cakes, and in preparing fruit jelly products and soft drinks."
Also, they note that pectins with DE less than 60 per cent can bind and remove heavy metals from the body, making the pumpkin pectin interesting as a nutritional recommendation for those who work with such metals.
Further work is clearly needed to characterise fully the pectins, as well as exploring the full potential of this source of pectin.
Source: Food Hydrocolloids (Elsevier)
Published on-line ahead of print, doi: 10.1016/j.foodhyd.2007.04.002
"Pectin extraction from pumpkin with the aid of microbial enzymes"
Authors: N.M. Ptichkina, O.A. Markina, G.N. Rumyantseva