Effect Of Lotus-seed Starch Quality On Rheology And Shelf Life Of Lotus-seed Juice

Lotus-seed, belonging to Nympheaceae Nelumbo Adans, is an important high-quality and special local resource and distributes widely in China. In this paper, A exact handy and fast method of determining amylose content of lotus-seed was established by improving iodine colorimetry, meanwhile twenty-two representive wild and cultivar varieties of lotus-seed in China were collected and their starch quality were studied; then processing technics of lotus-seed juice was optimized. Base on the study, liquid type of lotus-seed juice and effect of starch quality on rheology changes of lotus-seed juice in the storage were discussed, finally efect of starch quality on shelf life of lotus-seed juice was studied. The study could offer academic basis for optimizing materials of lotus-seed juice, decisions of technics optimization and quality control, and the results provided basic data for development of natural lotus-seed starch and quality control of lotus-seed products, meanwhile the study offered valuable reference for the processing of starchy products.1. A fast exact and handy method of determining amylose content of lotus-seed was established by improving iodine colorimetry; Base on the method, starch quality of twenty-two representive varieties of lotus-seed in China were studied. The results showed that optimal absorbing wavelength of improved iodine colorimetry method was 630nm and standard curve of amylose was y = 0.471x - 0.017, R=0.999, and the method was fast exact and handy by experiment proving. The results also showed that lotus-seed belonged to high-starch food. The average starch content is 41%, standard deviation is 12.41 and the differences of starch content of the varieties are significant; The differences of AC content of the varieties are also significant, the average content is 14.81%. The highest AC content is Zhejiang Liyehonghua lotus-seed, 21.25%. The two wild lotus-seeds (wild Honghu lotus-seed and Baiyangdian wild lotus-seed) contain lower AC-6.151% and 7.578% respectively. The two wild lotus-seeds are excellent materials for lotus-seed juice.2. Optimal processing technics of lotus-seed juice was discussed while Jianning huapai lotus-seed was material. The single-factor experiment showed that stability of lotus-seed juice was best when homogeneous press was 60MPa. Effect of Xanthan Gum, Glycerin monostearate and SE-11 on stability of lotus-seed juice were studied through orthogonal experiments. The results showed that optimal conditions of lotus-seed juice's stabilizers were Xanthan Gum 0%, Glycerin monostearate 0.15% and SE-11 0.15%, and Xanthan Gum destroyed stability of lotus-seed juice on the contrary.3. Seven varieties of lotus-seed were chosen for materials according to AC, lotus-seed juice was produced according to optimal technics, then rheology and retrogradation deposition...