Preparation, structure, and digestibility of crystalline A- and B-type aggregates from debranched waxy starches.
Highly crystalline A- and B-type aggregates were prepared from short linear α-1,4 glucans generated from completely debranched waxy maize and waxy potato starches by manipulating the chain length and crystallization conditions including starch solids concentration and crystallization temperature. The A-type crystalline products were more resistant to enzyme digestion than the B-type crystalline products, and the digestibility of the A- and B-type allomorphs was not correlated with the size of the aggregates formed. Annealing increased the peak melting temperature of the B-type crystallites, making it similar to that of the A-type crystallites, but did not improve the enzyme resistance of the B-type crystalline products. The possible reason for these results was due to the compact morphology as well as the denser packing pattern of double helices in A-type crystallites. Our observations counter the fact that most B-type native starches are more enzyme-resistant than A-type native starches. Crystalline type per se does not seem to be the key factor that controls the digestibility of native starch granules; the resistance of native starches with a B-type X-ray diffraction pattern is probably attributed to the other structural features in starch granules.
Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA.
Liming
L
Cai
Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA. Electronic address: ycshi@ksu.edu.
Yong-Cheng
YC
Shi
D055162:Biocatalysis; D003460:Crystallization; D005936:Glucans / Q000737:chemistry*; D006868:Hydrolysis; D010316:Particle Size; D011198:Solanum tuberosum / Q000737:chemistry*; D013213:Starch / Q000737:chemistry*; D014961:X-Ray Diffraction; D003313:Zea mays / Q000737:chemistry*
D005936:Glucans; D013213:Starch
Annealing; Debranching; Digestibility; Short-chain amylose; Starch crystals