Basic Study On Accumulation And Utilization Of Starch In Bulbs Of Lycoris

Starches are rich in bulbs of Lycoris. But the development and utilization of Lycoris starches were very limited.In this paper, many methods were used to study and analyze Lycoris chinensis,Lycoris aurea and Lycoris radiata starches. The results provided essential data for study on growth of Lycoris bulbs, and also provided theoretical bases for the practical use of Lycoris starches. The main results were as follows:1.The content of starch (total starch, amylose starch) and sugar (soluble sugar, reducing sugar) were changed with the changing of growth stages. Generally speaking, the content of these substance in the bulb plate were lower than in the scales, in Lycoris aurea were higher than in the other two. Both content of starch and sugar in exterior,middle,interior scales were different, showing a complex law of nutrient accumulation and use. The soluble sugar and starch were the main transportation and deposited forms of carbon nutrient in bulbs of Lycoris.2.Starch granule distribution characteristics in Lycoris chinensis bulb was analyzed. The experimental result indicated that it showed single peak curve in frequency of starch granules with the increasing of the area. The size of starch granules in the bulb plate was uniform, and smaller than it of starch granules in the scales. The percentages of large and small starch granules in Lycoris chinensis of different size had no significant difference.The percentages in the upper,middle,lower part of the bulb had no significant difference. But they had significant differences in exterior,middle,interior scales.3.The extraction of Lycoris chinensis starch was studied. The primary factors affected extraction in L.chinensis were the type of solution, pH value, material-liquid ratio,marinating time and subsiding time. All of the above factors had high significant influences. After single factor tests and orthogonal experiments L9(34), the optimum conditionwas concluded as follows: aqueous NaOH was used as extract liquid, pH value was 9.0, material-water ratio was 1:4, marinating time was 6h, and subsiding time was 4h. Under this condition, the extraction rates were over 80%.4.Properties of starches isolated from the three species of Lycoris bulbs with alkali extraction method were studied. The content of amylose were different of the three species of Lycoris starches, the highest was Lycoris aurea. The granular size was not even. The granule was diverse in shape. Obvious crosses were observed under polarized light microscope. The X-ray diffraction pattern was C-type. Analysis of pasting properties showed: the solubility, swelling power, freeze-thaw stability and clarity were low. The gelatinization temperatures were high investigated using DSC. There were significant differences in some properties of the three species of Lycoris starches, and there were different degrees of relevance among different physicochemical propertes.