EXTRACTION OF PECTIN FROM TEJOCOTE (CRATA EGUS-MEXICANA) BY ACID-HYDROLYSIS AND BY ION-EXCHANGE RESINS

Extraction of pectin from tejocote (Crataegus mexicana) by acid hydrol ysis and by ion exchange resins was undertaken at laboratory level. A fractionated factorial experimental design was employed for acid hydro lysis in which the variables were the pH (1.5 and 3.0), temperature (8 and 90 degrees C), extraction time (45 and 90 min) and the ratio of e xtraction volume to raw material (85/5 and 95/5). Pectin yield and gel strength ere considered as the response variables. Esterification per centage and purity (galacturonic acid percentage) were used as quality indicators. The best acid hydrolysis treatments were achieved at 8 de grees C, pH of 1.5, 85/15 ratio of volume of extraction to raw materia l at both extraction times of 4 and 90 min. Under these conditions, th e pectin yield was near 1% and the gel strength was higher than hose r eported for lemon peel extracted pectins. The acid hydrolysis treatmen t that delivered the pectins;Kith higher yields and better quality wer e repeated using ion exchange resins. The gels obtained by ion exchang e resins showed the highest gel strengths, but lower yields than he ac id hydrolysis gels. The results indicate that the pectin obtained from tejocote is of a comparable quality to that obtained from citric mate rials, so that it may be considered as an alternative source for obtai ning pectin.