Chemical composition and thermal properties of Chilean Araucaria araucana starch

摘要

Starch isolated from Chilean Araucaria araucana seed was characterized as a follow-up on a previous study. The apparent amylose (AMM) content determined by potentiometric titration was 28%. The chain length distribution profile of amylopectin (AP) showed two peaks at polymerization degrees (DP) of 12 and 43-44. Around 51% of unit chains had DP in the range 13-24. The average DP of AP branch chains was 19.6%. The molecular weight distribution of A. araucana starch analyzed by Sepharose CL 2B is also reported. The ratio of blue value to total carbohydrates was 0.30 for the AP peak, which is characteristic of a low proportion of long lateral chains. The gelatinization temperature and enthalpy determined by DSC were 65.6 degrees C and 14.5 J/g, respectively.