Characteristics of canaryseed (Phalaris canariensis L.) starch

摘要

Canaryseed starches from three locations were isolated by an alkali steeping process and evaluated for their chemical, pasting and structural properties by amylograph, scanning electron microscope (SEM), differential scanning calorimeter, X-ray diffractometer and image analysis, in comparison with isolated wheat starch. The average yield of canaryseed starch was 50+/-2.9g starch per 100g of great with a mean extraction efficiency of 77%. The starch isolates contained from 93 to 97% starch with amylose contents ranging from 16 to 22%. Canaryseed starch was uniform in appearance, being small polygonal granules having an average diameter of 2.0 mu m. The granules were stable when subjected to shear and heat effects as indicated by visco/amylograph response and SEM-photomicrographs. The transition temperatures (peak and conclusion) and enthalpy of gelatinization of canaryseed starch were higher than those of wheat starch. Canaryseed starch showed major peaks around d-spacings of 5.9, 5.2, 4.8 and 3.8 Angstrom similar to wheat starch which are characteristics of an A-type starch. Canaryseed starch was also more susceptible to a-amylase hydrolysis and more soluble in dimethyl sulfoxide as compared with wheat starch. Based on its ease of extraction and functional properties, canaryseed starch could have potential for food and non-food uses.