Some Properties of Normal‐ and Waxy‐Type Starches of Amaranthus hypochondriacus L

Abstract

Starch granules were prepared from seeds of two types of Amaranthus hypochondriacus L., which are native to Nepal. The perisperm of one type of seeds stained reddish‐brown with iodine solution and that of the other blue. Starch granules had round shape of about 1 μm diameter. X‐ray diffraction diagrams were very similar each other and identical with the corresponding ones of rice and maize starches (A‐type). Amylose contents and distribution of average chain‐lengths of amylopectin were determined by gel filtration for isoamylase‐debranched starches. Amylose content was about 14% and 0%, resp. Both types of Amaranthus starches had typical amylopectin nearly identical with those of rice and maize starches. Starch‐granule digestibility by amylases and pasting characteristics of the Amaranthus starches were similar to those of fine starch granules.

Some properties of starches of grain amaranths and several millets.

“…Gelatinization profiles of starches of the grain amaranths (Figs. 5a 1-5) are very similar to those reported by Kainuma et al (17) for fine starch granules such as those of Saponaria vaccaria as described earlier (2). Starches of A. caudatus #76325 exhibited the lowest temperature for initiation of gelatinization (Figs.…”

“…DISCUSSION We confirmed that there are both normal and waxy-types in the same species of Amaranthaceae, A. hypochondriacus L., by the investigation of properties of starches isolated from the seeds (Table 1). Starch granules of A. hypochondriacus #76338-2 consist of nearly 100% typical amylopectin the same as those of #76343-1 reported previously (2). The widespread distribution of starches staining red with iodine has been recognized for the past century (1).…”

“…This apparent amylose content may be due to the measurement technique used, to the effect of non-waxy starch granules from maternal tissue, to differences in the degree of branching, or to the presence of some linear materials as described by Shannon and Garwood (22). A small percentage of amylose usually was present in samples of commercially milled waxy maize starch (2), and this was due to contamination by normal starch, as was readily observed by light micros copy (1). When iodine was added, the presence of a few deep-blue granules among those staining reddish-brown was observed.…”

“…), maize (Zea mays L.), proso millet (Panicum miliaceum L.), rice (Oryza sativa L.) and sorghum (Sorghum bicolor (L.) Moench) among cultivated Gramineae (1). These mutants produce starch granules in the endsperm and the pollen which stain red with iodine and which contain nearly (2). Seeds of proso millet SGK-110 were collected in Afghanistan in 1978, and proso millet #76373 and 76382 were collected in Nara Prefecture, Japan in 1976, by Sakamoto.…”

“…Starch granules were isolated from the seeds by a modification of the method of MacMasters et al (7) combined with Schoch's method (8) as described earlier (2). About 10g each of the seeds of grain amaranths and proso millet except #76382 (about 2g of seeds) and about 20g each of the seeds of the other millets were used for preparation of starch granules.…”