A A C C   2 0 0 0   A n n u a l   M e e t i n g

The objective of this study was to optimize a laboratory starch extraction procedure to obtain maximum starch yields with minimum disruption or modification of granules. Two commonly used laboratory small-scale starch extraction procedures were compared for their impact on yield, protein content, and thermal properties. The different treatments used in the study were steeping time (24, 48, or 72 hr), numbers of kernels extracted (2, 5, or 10 kernels), and starch isolation methods (sedimentation or centrifugation). Compared to longer steeping times, starch extracted after steeping for 24 hr and purified by the sedimentation method had a lower gelatinization onset temperature and a wider gelatinization temperature range, but did not differ in the energy required for starch gelatinization. Starch extracted from fewer kernels, or using centrifugation, had a higher protein content. A comparison of the granule size distribution showed that starch extracted using sedimentation had a lower mean granule size and a more skewed distribution than starch extracted using centrifugation. This study, therefore, suggests that soaking seeds for less than 48 hr and using the sedimentation procedure are preferred to minimize protein contamination and to minimize alterations in starch thermal properties for laboratory research purposes.