Study On The Technology Of Extracting Insoluble Dietary Fiber From Red Algae's Residue

As an important component of function food, dietary fiber has attracted more and more attention during the function food development. Red algae's residue is the wastes from gelidium, gracilaria and eucheuma left after the extraction of agar and carrageenan, which includes plenty of dietary fiber and has been wasted as garbage.The aim of the research is to extract IDF from red algae residue respectively using chemical methods, enzymatic and chemical - enzyme binding methods. Moreover, the content of IDF by these methods have been analyzed and compared.By the single-factor experiment and the orthogonal experiment, the optimal condition for the extraction of IDF from red algae's residue were that: the rate of raw material to water was l:8. Then the material was soaked in the NaOH at pH=9, added 0.4% trypsin and 6% lipase, extracted for 3h at 40℃, washed to neutrality,dried for 4h at 60℃, and comminuted in the end, and the yield was 54.0%.The research studied the processing of bleaching the product twice extracted by the optimal processing to increase the product's whiteness. By the orthogonal experiment,, the most optimal conditions of IDF bleaching were that: the product was bleached once, the solid-liquid ration was 1:5, the concentration of NaClO was 8%, the process temperature was 40℃at pH=4 for 30min. The whiteness of the product by the first bleaching process was increased from 6.20 to 54.10. The color of the product was creamy-white.The IDF content was 93.61%, the protein content 1.42%, the fat content 1.37%, the whiteness 54.10. Its water holding capacity and swelling force were 5.05g/g and 6.47mL/g respectively, which were higher than the standards of western countries.(water holding capacity was 4mL/g, swelling force was 4g/g)...