| Gracilaria, Eucheuma, Sargassum and Laminaria japonica belong to massive economic seaweeds, and they are plentiful and rich in algin, cellulose, hemicellulose and minerals. So they are the high quality materials for producing dietary fibers (DF). At present, the four seaweeds mainly are used to produce food additives, which have the lower benefit because of their supplies exceeding demands, products unsalable and price falling. In order to resolve the problems, the nutrient compositions of Gracilaria, Eucheuma and Sargassum were analyzed and evaluated; and the seaweed dietary fibers which had the healthy functions were extracted from the four seaweeds by the new method. At the same time, the toxicology and functional properties of the seaweed dietary fibers were studied to provide theories for their safety and healthy functions. The study will expand the research category of dietary fibers and promote the further development of seaweed breeding aquatics industry and processing industry in our country. The main tasks and conclusions of the paper are as follows:1. The nutrient components of five Gracilaria samples which were from different species or grew in different sea areas were analyzed and compared with Laminaria japonica and porphyrya for evaluation in nutriology. The results showed that the content of Gracilaria DF reached 60%~70%, close to Laminaria japonica and porphyra. In addition, the content of protein was above 15% and the content of fat was below 2.5% and the Gracilaria was rich in minerals, microelements and vitamins. Therefore, Gracilaria was a good natural material for healthy foods, which had higher DF, higher protein, lower fat, lower calorie and rich minerals, microelements and vitamins and especially was fit for dietary fiber foods.2. The nutrient components of Eucheuma samples of Indonesia and Hainan provincewere analyzed and compared with Laminaria japonica and porphyra for evaluation in nutriology. The results showed that the carbohydrate contents of Eucheuma of Indonesia and Hainan province were 77.97% and 76.99%, respectively. The protein contents of Eucheuma of Indonesia and Hainan province were 3.17% and 2.23%? respectively. And Eucheuma was rich in minerals, microelements and vitamins. Therefore, Eucheuma was a good natural material for healthy foods, which had higher DF, lower fat, lower calorie and rich minerals, microelements and vitamins and especially was fit for dietary fiber foods.3. The nutrient components of six Sargassum samples which were from different species or grew in different sea areas were analyzed and compared with Laminaria japonica and porphyra for evaluation in nutriology. The results showed that Sargassum was rich in dietary fiber, in addition to the starch of brown alga, mainly was algin, fucoidan, cellulose and hemicellulose and reached 60%, close to Laminaria japonica and porphyra and the content of protein was above 7.0%. And Sargassum was rich in minerals, microelements and vitamins. Therefore, Sargassum was a good natural material for healthy foods, which had higher DF, lower fat, lower calorie and rich minerals, microelements and vitamins and especially was fit for dietary fiber foods.4. The technologic conditions of Gracilaria DF extraction was researched. The optimum technologic conditions of Gracilaria DF extraction had been obtained by orthogonal test, and the Gracilaria DF had been produced under the optimum conditions. The results showed that the yield of Gracilaria DF was 28.3%, and its color was whiter. The contents of Gracilaria DF, calcium and phosphorus were 92.83%, 1.08% and 0.068%, respectively (dry basis). The expansive capacity and water holding capacity were 9.0mL/g and 825%, respectively. The data of the quality and the functional properties far exceeded the standard of the bran DF of western nations with dry basis contents of dietary fiber 47%, the expansive capacity 4mL/g and water holding capacity 400%.5. The technologic conditions of Eucheuma DF extraction was researched. The optimum technologic conditions of Eucheuma DF extraction had been obtained by orthogonal test, and the Eucheuma DF had been produced under the optimum conditions. The results showed that the yield of Eucheuma DF was 32.4%, and itscolor was whiter. The contents of Eucheuma DF, calcium and phosphorus were 82.57%, 2.13% and 0.013%, respectively (dry basis). The expansive capacity and water holding capacity were 24.5mIVg and 1450%, respectively. The data of the quality and the functional properties far exceeded the standard of the bran DF of western nations.6. The technologic conditions of Sargassum DF extraction was researched. The optimum technologic conditions of Sargassum DF extraction had been obtained by orthogonal test. The results showed that the yield of Sargassum DF was 7.9%, and its color was whiter. The contents of Sargassum DF, calcium and phosphorus were 81.08%, 6.82% and 0.23%, respectively (dry basis). The expansive capacity and water holding capacity were 22mL/g and 1250%, respectively. The data of the quality and the functional properties far exceeded the standard of the bran DF of western nations.7. Combining the enzyme technology and chemical disposing, the extraction technology of Laminaria japonica DF was studied. The optimum technologic conditions of Laminaria japonica DF extraction had been obtained by orthogonal test. The Laminaria japonica DF had been produced under the optimum conditions. The results showed that the yield of Laminaria japonica DF was 27.3%, and its color was whiter. The contents of Laminaria japonica DF and calcium were 73.3% and 7.5%, respectively. The expansive capacity and water holding capacity were 55mL/g and 2650%, respectively. The data of the quality and the functional properties far exceeded the standard of the bran DF of western nations.8. In order to assess the food safety of the 4 seaweed DF, the acute toxicity test, Ames test, micronucleus test of marrow cell as well as chromosome aberration test, teratogenicity tests and 30 days feeding test were carried out to judge the acute toxicity, genetic toxicity, embryo toxicity and general toxicity according to the methods of our country for toxicological assessment on food safety. The results showed that the LD50 of the 4 seaweed DF were more than 15000mg/kg.bw, belonging to nontoxic level; there was no obvious toxicity, side-effect and dose dependently, and genetic toxicity, teratogenicity effect and mutabginicity wasn't observed with range of high dose. Therefore, the 4 DF were an edible and safe food without obvious signs of toxicity to trial animal in according with the demands of procedures and methods for toxicological assessment on food safety.9. The scavenging effect of the 4 seaweed DF was studied by free radical assay systems, which included hydroxyl radical system, superoxide radical system, alkyl radical oxidation system and DPPH system. The results showed that IC50 of Gracilaria DF ,Eucheuma DF, Sargassum DF and Laminaria japonica DF were 5.2 mg/mL, 5.5 mg/mL, 4.4 mg/mL, and 4.1 mg/mL respectively in hydroxyl radical assay system. In superoxide radical assay system, IC50 of Gracilaria DF and Eucheuma DF were 4.8 mg/mL and 5.3 mg/mL, respectively; while for Sargassum DF and Laminaria japonica DF, free radical scavenging ratio were as high as 36% and 42%, respectively. In alkyl radical oxidation system, the scavenging ratio of Gracilaria DF and Eucheuma DF on free radical were about 36% and 26%, respectively ,which were lower than that of Sargassum DF and Laminaria japonica DF, IC50 4.1 mg/mL and 3.5 mg/mL respectively. In DPPH system, the scavenging ratio of Gracilaria DF and Eucheuma DF on free radical were 31%, 11% and 26%, respectively; while for Laminaria japonica DF, IC50 was 6.2 mg/mL. It was proved that the 4 seaweed DF had the scavenging effect on free radical compared with special positive control in these systems.10. The adsorption effect of the 4 seaweed DF and wheat bran on exogenous estrogens was studied by simulating the environment of stomach and small intestine in vitro, and feeding rat in vivo. The results showed that the adsorption effect of the DF on estrogens was better in simulating small intestine environments than that in simulating stomach environment. Especially the adsorption quantity of Laminaria japonica DF and Sargassum DF on estrogens in small intestine environment were 10 times and 6.2 times than that in the stomach environment, respectively and higher than wheat bran DF, Gracilaria DF and Eucheuma DF. The adsorption ability on estrogens of Laminaria japonica DF was the strongest in the small intestine environment and the adsorption quantity on estradiol was 108ug/g. It was 1.5 times greater than that of Sargassum DF, 1.8 times than wheat bran DF, 3.1 times than Gracilaria DF and 3.0 times than that of Eucheuma DF. The adsorption ability on estrogens of Laminaria japonica DF and Sargassum DF were stronger than that of wheat bran DF. The adsorption ability on exogenous estrogens of brown seaweed DF (Sargassum and Laminaria japonica) was stronger than that of red seaweed DF (Gracilaria and Eucheuma). So, it can be presumed that the adsorption on estrogens by DF focused onthe small intestine. The adsorption abilities of the 4 seaweed DF on exogenous estrogens in vivo were as follow: Laminaria japonica DF>Sargassum D$>Eucheuma DF>Gracilaria DF .Compared with the wheat bran DF, the adsorption ability of Laminaria japonica DF and Sargassum DF was stronger, and the adsorption ratio on estradiol were 50.8% and 39.3%, respectively . Adsorption ratio of Sargassum DF and Laminaria japonica DF was 1.6 times and 1.2 times than that of wheat bran DF. 11. The adsorption effect of seaweed DF on exogenous Cd2+, Pb2+, Hg2+ and NO2" was studied by simulating the condition of stomach and small intestine in vitro ,and feeding rat in vivo. The results showed that the adsorption effect on NO2" of the 4 seaweed DF and wheat bran DF were related with pH and DF species, the adsorption quantity on NO2" at pH2.0 is twice as much as that at pH7.0. Among them, the adsorption ability of Laminaria japonica DF was the strongest, and the adsorption quantity at pH2.0 and pH7.0 were 1.19 mg/g and 0.74mg/g, respectively .The adsorption abilities of DF on NO2" were as follows: Laminaria japonica DF>Eucheuma DF>Gracilaria DF>wheat bran DF>Sargassum DF. The adsorption effect on Cd2+, Pb2+, Hg2+ of the DF were related with the pH and DF species and heavy metals species, the adsorption effect were better at pH 7.0 than that at pH 2.0.The DF had the best adsorption effect on Pb2+ among these heavy metals. The adsorption quantity of Laminaria japonica DF on Pb2+ at pH2.0 and pH7.0 were 114.48mg/g and 116.08mg/g, respectively .The adsorption ability of the 5 DF on Pb2+ were as follows: Laminaria japonica DF>Eucheuma DF>Gracilaria DF>wheat bran DF>Sargassum DF. And the scavenging ability on NO2" of the DF in vivo were significantly higher than that of control (p<0.05) .The scavenging abilities were as follows: Eucheuma DF>wheat bran DF>Gracilaria T)F>Sargassum DF > Laminaria japonica DF>control. Among them, the scavenging ability of Eucheuma DF was the strongest and reached 24.74%. The DF had significantly higher scavenging ability ona Cd2+, Pb2+, Hg2+ than that of control (p<0.05 ) . The scavenging abilities of DF on heavy metals were as follows: Eucheuma DF>Laminaria japonica DF>wheat bran DF>Gracilaria DF>Sargassum DF > control. Among them, the scavenging ability of Eucheuma DF on Cd2+ was the strongest and reached 79.65%. The tests proved that the adsorption ability of the seaweed DF on NCVwere weaker, but stronger on heavy metals. So the DF had the important value in discharging the heavy metals and NO2"in human body for reducing the cumulative toxicity in human body. 12. The constipated volunteers were chosen to evaluate the functional properties of the seaweed DF and wheat bran. Everyone took these DF in dose of 2g/once.body, three times a day, and continue for 30ds. The results showed that those who took the Gracilaria DF , the normal ratio of constipated patients was 52.5%, essential normal ratio was 37.5% and efficiency reached 100%.The total efficiency of Eucheuma DF reached 100% and the normal ratio and essential normal were 87.35% and 10.0% .respectively .The total efficiency of Sargassum DF reached 100% and the normal ratio and essential normal were 70.0% and 25.0% Respectively .The total efficiency of Laminaria japonica DF reached 100% and the normal ratio and essential normal were 92.5% and 5%, respectively. The total efficiency of wheat bran DF reached 100% and the normal ratio and essential normal were 37.5% and 30%, respectively .The 4 seaweed DF had the significantly laxative effect on constipated patients. Among them, the Laminaria japonica DF had the best effect, secondly Eucheuma DF and Sargassum DF, last the Gracilaria DF. The effect of the 4 seaweed DF on constipated patients was better than that of wheat bran DF from terricolous vegetables.
|
PDF Full Text Request