4. Conclusions
This study demonstrates that polysaccharides suitable as a food thickener can be obtained from commonly available fruit sources like peach, blackcurrant, raspberry, strawberry, plum and vegetable like carrot using citric acid extraction. Pectinolytic enzymes acting in fresh plant tissues have an influence on the properties of extracted pectin enriched fractions. Despite the fact, that isolated polysaccharides were found to have a lower uronic acid content than commercial apple and citrus pectins, pectin enriched fractions extracted using citric acid demonstrated rheological properties which are useful in gelling additives. Pectin enriched fractions extracted from different plant sources demonstrated the thixotropic effect, pseudoplastic flow behaviour and high viscosity which allow for the thickening and gelling of food fluids. The chemical properties as well as the rheological behaviour of analyzed polysaccharides from different sources differed from each other in the value of various parameters. This diversity presents great opportunities for new applications of pectins in the food industry. The desired properties of pectins, such as acting as gelling or stabi-lizing agents, as well as being used as functional food ingredients may be achieved by the appropriate selection of the plant source. Moreover, the use of citric acid for pectin enriched fractions extraction is an ecological alternative to the mineral acids commonly used in industry.
