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Abstract

β-glucan is a dietary fiber-type complex sugar (polysaccharide) derived from the cellwall of baker's yeast (Saccharomyces cerevisiae), cereals (oat and barley), and mushrooms.Principally, yeast and mushroom contains a mixture of mainly β- 1,3-glucans and β-1,6-glucans. These substances stimulate the immune system. β-glucans also exhibithypocholesterolemic and cancer prevention properties. Thailand had some commerciallyavailable edible mushrooms; thus, eight edible mushrooms were selected for screening oftheir β-glucan content. It was found that β-glucan contents in Schizophylum commune Fr.,Pleurotus sajor-coju (Fr.) Sing, Pleurotus osttreatus (Fr.) Kummer, Auricularia auricula Judae,Volvariella vovacea (Bull, Ex, Fr.) Sing, Lentinus edodes (Berk.) Sing, Flammulina velutipes(Curt., Ex, Fr.) Sing and Boletus griseipurpureus Corner were 59.87%, 37.61%, 32.93%,31.51%, 27.85%, 25.50%, 19.37% and 12.09%, respectively. Therefore Auricularia auriculaJudae was selected to study the optimal conditions for extraction of β-glucan. Auriculariaauricula Judae has lowest cost of raw material per β-glucan content ( 2.38 Bath/ gram β-glucan). It contained 6.00% of total dietary fiber (TDF), whereas soluble dietary fiber (SDF)was 5.57% and insoluble dietary fiber (IDF) was 0.46 %.Extraction of β - glucan from Auricularia auricula Judae was done at 121 °C and highpressure for 30, 45 and 90 minutes. The dried powder of Auricularia auricula Judae waspre-hydrolyzed by cellulase at 50 U/ml for 360 minutes, then the molecular weightdistribution of β - glucan was analyzed using High Perfomance Size ExclusionChromatography (HPSEC). It was found that at temperature of 121 °C, at various times, thecontent (49. 92%) and molecular weight of β-glucans (ten to the power four - ten to the power five) Da were not significantlydifferent. (p>0.05). When extraction temperature was increased to 130 °C, B-glucans hadmolecular weight of ten to the power four - ten to the power seven Da. Opitimal condition for extraction of f- glucan was 130 °Cfor 30 minutes. The extract and sediment had β-glucans of 9.08% and 36.59%, respectively.β-glucan was purified by removal of monosaccharides using ultrafiltration. Themembranes with molecular weight cutoff (MWCO) of 5, 10 and 30 kDa, cross flow velocities(CFV) of 1 m/s and TMP of 1.5 bar using concentration mode. β-glucan were analyzed byHPSEC. It was found that 30 kDa showed the best for removal of monosaccharides.Results on study of β-glucan on promoting of probiotics 2 strain (Bifidobacteriumanimalis subsp. lactis (BB-12) and Lactobacillus plantarum TISTR 1465) cultivation on MRSplates at 37 °C in anaerobic jar for 48 h. It was found the β-glucan from Auricularia auriculaJudae could promote the growth of L. plantarum TISTR 1465 by increasing from 5.13x10 to the power sixto 2.37x10 to the power seven CFU/ml. Inulin showed the highest growth promotion of BB-12 by increase from1.01x10 to the power eight to 3.73x10 to the power eight CFU/ml. β-glucan from Auricularia auricula Judae showed slightlyincrease of BB-12 at 12 hr from 1.40x10 to the power eight to 1.49x10 to the power eight CFU/ml. It can be concluded that β-glucan from Auricularia auricula Judae has specific growth promotion growth of L.plantarum TISTR 1465 more than BB-12. So that β-glucan from Auricularia auricula Judaeis candidate prebiotic.