Twenty algal-oligosaccharide-lysates (AOLs), derived from six agars and four algal polysaccharide extracts (APEs), were treated first with agarases with 250 or 500 agarase activity units (AU), which were produced from the agar-liquefying bacterial strain Pseudomonas vesicularis MA103, named MA103-agarases. The AOLs were then treated with agarases (250 or 500 AU) derived from the agar-softening bacterial strain Aeromonas salmonicida MAEF108, named MAEF108-agarases. Anti-oxidative properties of the AOLs were evaluated by five in vitro methods. The AOL obtained from the APE of Porphyra dentate, digested by 250 AU of MA103-agarases, and by 250 AU of MAEF108-agarases, designated as A 250 -Por, showed better results than the 19 other AOLs. This result is in accordance with the level of soluble total polyphenols (STP) of A 250 -Por, which was also higher than the remainder of the AOLs tested. The AOL derived from the APE of P. dentate, digested by 500 AU of MA103-agarases and then 500 AU of MAEF108-agarases, and designated as B 500 -Por, displayed the second highest data in four potential evaluation methods, except in H 2 O 2 scavenging capacity. In this study, certain agars or APEs digested by specific agarases can present an increasing antioxidative capacity. These agars include Bitek agar, Agar powder, Bacteriological, Agar Bacteriological, and Guanghui agar, plus APEs of Gracilaria sp. and Monostroma nitidum decomposed stepwise by two agarases. The fraction of polyphenols (<1 kDa) that were derived from A 250 -Por showed anti-oxidative activities on a,a-diphenyl-b-picrylhydrazyl (DPPH) assay and reducing power determination, while the remaining four agar-lytic fractions obtained from A 250 -Por did not exhibit anti-oxidative activity. This phenomenon may suggest that anti-oxidative properties of AOLs originate in polyphenols. Algal-oligosaccharide-lysates may have potential use as a health food.

Algal-oligosaccharide-lysates (AOL), derived from six agars and four algal polysaccharide extracts (APE), were treated with 100-500 activity units (AU) of MA103-agarases or MAEF108-agarases, and their antioxidative properties evaluated. Soluble total polyphenols (TP) were between 462.2 ± 1.6 gallic acid equivalents (GAE, mg/mL) and 70.6 ± 17.4 GAE. The DPPH radical scavenging capacity of all AOL went from 68.3 ± 0.7% to 0.5 ± 0.1%. The ferrous ion chelating capacity of all AOL went from 93.1 ± 0.2% to 21.7 ± 0.9%. Evaluation of the H 2 O 2 scavenging capacity of all AOL was between 35.9 ± 5.4% and 0.1 ± 0.2%. The reducing power of all AOL went from 51.3 ± 2.6 to 3.2 ± 6.8 expressed as mg/mL ascorbic acid. In DPPH radical scavenging capacity, ferrous ion chelating capacity and reducing power etc., the AOL derived from the APE of Porphyra dentate (digested by 500 AU of MAEF108-agarases) were highest, in all test sets. However, the AOL derived from the APE of Monostroma nitidum (digested by 500 AU of MAEF108-agarases) had the highest H 2 O 2 scavenging capacity in all test sets. The order of antioxidative activity performance of all AOL treated in this experiment, by these four antioxidative methods, is as follows: ferrous ion chelating capacity > DPPH radical scavenging capacity > H 2 O 2 scavenging capacity > reducing power; this may be related to their polyphenols, small molecular weight polysaccharides or simple sugar constituents. In this study, it is demonstrated that various agarases derived from algal oligosaccharide mixtures possess good potential for use as a health food, due to their antioxidative capacity.

Seaweeds have an extremely numerous of species in the world and been able to be divided into several developmental systems. Broadly, three types of seaweeds can be defined according to their color: brown seaweeds, green seaweeds, and red seaweeds. Thousands of years ago, mankind used seaweeds as food and medicine. Seaweed extracts are gaining increasing attention due to their unique composition and the potential for widespread use in industry. A variety of novel (green) extraction techniques have been devised for converting seaweed biomass into seaweed extracts, such as enzyme-assisted extraction (EAE), microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), supercritical fluid extraction (SFE), and ultrasound-assisted extraction (UAE), which are capable of extracting seaweeds' biologically active compounds without causing degradation. Seaweed extracts contain compounds, such as carbohydrates, proteins, minerals, oils, fats, and polyunsaturated fatty acids and abundant bioactive compounds, such as antioxidants, pigments, and sulfated seaweed polysaccharides (SWP), as well as antibacterial, antifungal, anti-inflammatory, antioxidation, antitumor, antiviral, and hypolipidemic effect. The purpose of this article is to describe the antioxidant activity of SWP of brown seaweeds, green seaweeds, and red seaweeds by novel assisted extraction.

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