دانلود رایگان مقاله پکتین فراکسیون غنی سازی شده رئولوژیکی و شیمیایی

ABSTRACT

Yield, properties and functionality of pectins depend on the source material and method of extraction. The objective of this work was to compare pectinolytic enzyme activity in fresh pulp as well as the physicochemical and rheological properties of polysaccharides extracted with citric acid from six new potential sources: fruit materials – peach, blackcurrant, raspberry, strawberry, plum and a vegetable Source: carrot. The uronic acid content of polysaccharides extracted in citric acid depended on pectinolytic enzymes activity in fresh plant tissues and ranged between 16.5 and 37.1%; which are slightly lower values than those of commercial pectins isolated from citrus and apple. The values of examined rheological parameters (viscosity, thixotropic effect, flow behaviour) demonstrated quality and possibility of pectin enriched fraction application as a food texture modifier. Pectin enriched fractions extracted from seasonal fruit and carrot with citric acid showed considerable potential as thickeners and gelling agents.

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.