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Introduction: Alginate is a biopolymer commonly in brown algae, high content, diversity in structure and bioactivity. They are applied to other fields such as food, functional food, pharmaceuticals, and heavy industry and extracted from Sargassum, Laminarin, Tubinaria and Sargassum polycystum species commonly grow in the world than another genus. The content, the antioxidant activity, and the physical chemistry properties of alginate extracting from the species did not exhibit in the previous studies. Methods: The study focused on the impact of various extraction conditions (temperature (40 to 90,oC), time (01 to 06, hours), the solvent-to-material ratio (10/1 to 40/1, v/w), solvent pH (8, 9, 10), and numbers of extraction (1, 2, and 3 times) on alginate content and its antioxidant activity, also evaluated sugar compositions, average molecular, viscosity, and 13C-NMR spectrum characteristics of alginate. Results: The results showed that the suitable condition for the extraction of alginate was for 4 hours at 60oC with the ratio of Na2CO3 (pH 9)-to-material (40/1, v/w) and one number of extraction. The highest alginate content was 176.22 mg uronic acid equivalent/g DW, corresponding to antioxidant activity (188.54 mg ascorbic acid equivalent/g DW). Alginate possessed the intrinsic viscosity (271.86, ƞ) and the average molecular weight (78.6, kD). Different sugar compositions of antioxidant alginate were fructose, fucose, mannose, galactose, rhamnose, mannose, and glucose. The 13C-NMR spectrum of antioxidant alginate exhibited chemical shifts of C sites of D-mannuronic (M) and L-guluronic (G), corresponded to C1, C2, C6, and C2, C3, C4, C5, C6, respectively. Conclusion: Alginate is non-toxic, therefore, antioxidant alginate extracting from brown algae Sargassum polycystum grown in Vietnam is a potential in functional food and pharmaceuticals.

Carrageenan is an anionic sulfated polysaccharide that accounts for a high content of red seaweed

Nowadays, people face many different dangers, such as stress, unsafety food, and environmental pollution, but not everyone suffers. Meanwhile, free radicals are the biggest threat for humans because they lead to over 80 different diseases composed of aging. Free radicals can only be eliminated or minimized with antioxidant foods or antioxidants. The chapter on the functional-antioxidant food presents the antioxidant functional food concept, the classification, the structure, and the extraction process of antioxidant ingredients. Various antioxidant substances such as protein (collagen), polysaccharides (fucoidans, alginates, glucosamines, inulins, laminarins, ulvans, and pectins), and secondary metabolites (polyphenols (phlorotannins, lignins, polyphenols), alkaloids, and flavonoids) also present. The production technology, the mechanism, the opportunity, and the challenge of antioxidants functional food also present in the current chapter. The current chapter also gives the production process of functional-antioxidant food composed of the capsule, the tablet, tube, the pills, the powder, and the effervescent tablet.

Objective: To investigate the content and antioxidant activities of polyphenol, the correlation between polyphenol content and their antioxidant activities, and phytochemistry compositions of different extracts from marine sponge Aaptos suberitoides commonly found growing in Nhatrang bay, Vietnam orienting application into functional food and pharmacy. Methods: Evaluating the toxicity of antioxidant polyphenol powder preparing from the initial concentrated extract was by the adjusted Behrens Karber method and a correlation between polyphenol content and antioxidant activities basing on the Pearson coefficient in Excel. Separating antioxidant polyphenol content was base on solvents polarization of n-hexane, chloroform, ethanol, ethyl acetate and n-butanol which the quantification of polyphenol content and antioxidant activities, and preliminary phytochemical compositions qualitative. Results: Antioxidant polyphenol powder did not affect mice weight during the assay time of 28 d. Polyphenol content and antioxidant activities got the highest value at chloroform extract in comparison to other extracts, a significant difference (p0.9). Polyphenol content (122.682 mg gallic acid equivalent ml-1), total antioxidant activity (368.183 mg ascorbic acid equivalent ml-1), reducing power activity (24.08 mg FeSO4 equivalent ml-1) and DPPH scavenging (72.48±1.54 %) were the highest values. Alkaloids, flavonoids, steroids, tannins and triterpenoids existed in initial methanol extract. Weakly polarized polyphenol content was 70.27% in comparison to initial methanol extract. Conclusion: Antioxidant polyphenol of sponge Aaptos suberitoides has the potential for application into the field of functional food and pharmaceuticals.

Alginate is a high-value biopolymer, exists in brown algae, and applied widely in numerous fields, for example, food, functional foods, and pharmaceutics. The study focused on the biophysical-chemistry characterization of alginate in brown algae species Sargassum dupplicatum grown commonly in Vietnam under the effect of NaCl, KCl, MgCl2, chitosan, carrageenan, and ethanol in different physical condition. Antioxidant activity of alginate and their compound was also studied. The results showed that Na_Alg, K_Alg, and Mg_Alg disperse the net style in the water. Ca_Alg, chitosan_Alg, and Carrageenan_Alg absorbed water and swelled for forming a sphere, yarn, and yarn in the water, respectively. Chitosan_Alg and carrageenan_Alg precipitated faster in ethanol, compared to Na_Alg, K_Alg, and Mg_Alg. 20% of ethanol did not cause the precipitation of Alginate salt, Chitosan_Alg, and carrageenan_Alg for 30 minutes. Alginate salt, Chitosan_Alg, and Carrageenan_Alg were full precipitated for 30 minutes when using ethanol concentration was more than 80%. Chitosan_Alg and Carrageenan_Alg occurred the precipitation in 20% of ethanol for 30 minutes. Total antioxidant activity and reducing power activity of chitosan_Alg got the highest value (a and b, respectively), compared to Carrageenan_Alg, Na_Alg, K_Alg, and Mg_Alg. The antioxidant activity difference in a group of Na_Alg, K_Alg, and Mg_Alg, and a group (Chitosan_Alg and Carrageenan_Alg) did not happen. The difference only occurred between the two groups.