| Abstract: | Abstract : A process for the micropropagation of Amorphophallus rivierii (elephant yam or konjac) and for the extraction and purification of the glucomannan polysaccharide from fresh konjac plant corms has been developed. This process involves extraction with 2-propanol, which has the additional benefit of extracting carotenoids as a potentially valuable side-product. Starch granules with an unusually high and homogeneous gelatinisation temperature range are normally present in the corms, particularly immature ones, and this greatly reduces the strength of gels formed using the glucomannan. Therefore, the extraction process also involves the selective hydrolysis of the starch, by α- and β-amylases that have been specially selected for an absence of contaminating β-mannanase or β-glucanase activity that would depolymerise the glucomannan and render it nonfunctional. Bacillus lichenformis α-amylase was preferred. Using this process pure glucomannan could be extracted which, when mixed with K -carrageenan, forms a gel almost twice as strong as locust bean gum-K -carrageenan gels of the same concentration. |
