Active polysaccharide compound nutrient with immunity-enhancing and fatigue-relieving activities and preparation thereof

A method of preparing a Mytilus edulis extract, comprising:

• (S11) subjecting Mytilus edulis to washing, shelling, de-byssus removal, grinding and freeze drying to obtain a Mytilus edulis freeze-dried powder;
• (S12) adding 20-25 parts by weight of the Mytilus edulis freeze-dried powder and 150-200 parts by weight of deionized water to a reactor to obtain an enzymatic hydrolysis system;
• and subjecting the enzymatic hydrolysis system to enzymatic hydrolysis;
• wherein the enzymatic hydrolysis comprises steps of:
• (S121a) heating the enzymatic hydrolysis system to 20-25° C.;
• cooling the enzymatic hydrolysis system to −45° C. at a rate of 15° C./min followed by keeping at −45° C. for 1 min;
• heating the enzymatic hydrolysis system to 20-25° C. at a rate of 10° C./min;
• adding an alkaline protease to the enzymatic hydrolysis system, wherein the alkaline protease is 1% by weight of the enzymatic hydrolysis system;
• adjusting the enzymatic hydrolysis system to pH 7.0-9.0;
• and heating the enzymatic hydrolysis system to 50-60° C. followed by reaction for 5-8 h;
• and
• (S121b) adjusting the enzymatic hydrolysis system to 40-55° C.;
• adding a first complex enzyme, chitosan, cysteine and sodium sulfite to the enzymatic hydrolysis system followed by adjustment to pH 6.0-6.5;
• and subjecting the enzymatic hydrolysis system simultaneously to pulsed magnetic field treatment and UV radiation for 10-12 h;
• wherein a weight ratio of the enzymatic hydrolysis system to the first complex enzyme to chitosan to cysteine to sodium sulfite is 1:0.05:0.02:0.03:0.02;
• the first complex enzyme is composed of phospholipase, papain and flavourzyme in a weight ratio of 1:0.5:0.5;
• the pulsed magnetic field treatment is performed at an intensity of 2.5-3.5 T using 20-30 pulses;
• and the UV radiation is performed at a power of 40 W and a wavelength of 180-280 nm for 40-60 min;
• (S122a) adjusting the enzymatic hydrolysis system to 20-25° C.;
• cooling the enzymatic hydrolysis system to −45° C. at a rate of 10° C./min followed by keeping at −45° C. for 0.5 min;
• heating the enzymatic hydrolysis system to 20-25° C. at a rate of 10° C./min;
• adding an acid protease to the enzymatic hydrolysis system, wherein the acid protease is 0.5% by weight of the enzymatic hydrolysis system;
• and adjusting the enzymatic hydrolysis system to pH 4.0-6.0 and 40-50° C. followed by reaction for 3-4 h;
• and
• (S122b) adjusting the enzymatic hydrolysis system to 40-55° C.;
• adding a second complex enzyme, chitosan, cysteine and sodium sulfite to the enzymatic hydrolysis system followed by adjustment to pH 6.0-6.5;
• and subjecting the enzymatic hydrolysis system to pulsed magnetic field treatment and UV radiation for 8-10 h;
• wherein a weight ratio of the enzymatic hydrolysis system to the second complex enzyme to chitosan to cysteine to sodium sulfite is 1:0.03:0.02:0.02:0.02;
• the second complex enzyme is composed of phospholipase, papain and flavourzyme in a weight ratio of 1:1:0.8;
• the pulsed magnetic field treatment is performed at an intensity of 2.0-3.0 T using 10-12 pulses;
• and the UV radiation is performed at a power of 40 W and a wavelength of 280-320 nm for 30-40 min;
• and
• (S123a) adjusting the enzymatic hydrolysis system to 40-55° C.;
• cooling the enzymatic hydrolysis system to −45° C. at a rate of 5° C./min followed by keeping at −45° C. for 0.5 min;
• heating the enzymatic hydrolysis system to 20-25° C. at a rate of 10° C./min;
• adding a neutral protease to the enzymatic hydrolysis system, wherein the neutral protease is 0.2% by weight of the enzymatic hydrolysis system;
• and adjusting the enzymatic hydrolysis system to pH 6.0-7.0 and 50-60° C. followed by reaction for 1-2 h;
• and
• (S123b) adjusting the enzymatic hydrolysis system to 40-55° C.;
• adding a third complex enzyme, chitosan, cysteine and sodium sulfite to the enzymatic hydrolysis system followed by adjustment to pH 6.0-6.5;
• and subjecting the enzymatic hydrolysis system to pulsed magnetic field treatment and UV radiation for 8-10 h;
• wherein a weight ratio of the enzymatic hydrolysis system to the third complex enzyme to chitosan to cysteine to sodium sulfite is 1:0.02:0.01:0.02:0.02;
• the third complex enzyme is composed of phospholipase, papain and flavourzyme in a weight ratio of 1:1.2:1.2;
• the pulsed magnetic field treatment is performed at an intensity of 1.8-2.0 T using 5-8 pulses;
• and the UV radiation is performed at a power of 40 W and a wavelength of 320-400 nm for 20-30 min;
• (S13) heating the enzymatic hydrolysis system to 90° C. followed by keeping at 90° C. for 10 min for enzyme inactivation to obtain a crude Mytilus edulis extract;
• (S14) mixing the crude Mytilus edulis extract with activated carbon under stirring followed by keeping at 55° C. for 60-90 min and centrifugation to collect a supernatant, wherein the activated carbon is 3% by weight of the crude Mytilus edulis extract;
• filtering the supernatant with diatomite at a pressure of 0.25-0.35 MPa to obtain a filtrate;
• mixing the filtrate with activated carbon followed by standing for 45-60 min and centrifugation to obtain a purified Mytilus edulis extract, wherein the activated carbon is 3% by weight of the filtrate;
• (S15) filtering the purified Mytilus edulis extract through a ceramic microfiltration membrane at 55-65° C. to obtain a first filtrate;
• filtering the first filtrate through a spiral-wound ultrafiltration membrane at 55-65° C. to obtain a second filtrate;
• concentrating the second filtrate through a spiral-wound reverse osmosis membrane at 35-40° C. to remove water, residual inorganic salts and impurities, so as to obtain a Mytilus edulis concentrate;
• and
• (S16) subjecting the Mytilus edulis concentrate to freeze-drying to obtain the Mytilus edulis extract.