| Euglena?-glucan crystal is a high-order aggregate of microfibers,and its crystallinity is close to 90%in natural state,so Euglena?-glucan can't be dissolved in water because of its structural characteristics.?-glucan has a wide range of biological activities.At present,Euglena?-glucan has been widely used in food,cosmetics,medicine and other fields,with almost no toxic or side effects.In this experiment,ultra-high pressure microfluidics were used to extract?-glucan from Euglena for the first time,and electron beam irradiation was used to degrade?-glucan from Euglena.On this basis,the degraded?-glucan was further purified by column chromatography,and the structural changes were analyzed by FT-IR,XRD and SEM.The specific research contents and conclusions are as follows:(1)In this paper,the effects of ultra-high pressure microfluidization time,pressure,solid-liquid ratio and SDS concentration on the extraction rate of?-glucan from Euglena nudiflora were studied by single factor and response surface design experiment.The results showed that the optimal extraction conditions of EBG were as follows:time 93 s,pressure 34 MPa,solid-liquid ratio 1?270 g/m L and SDS concentration 4.2 g/L.Under these conditions,the extraction rate of EBG was 80.27%.Compared with Congo red test and FT-IR of Euglena beta-glucan standard(EBG),the results showed that EBG extracted by ultra-high pressure microfluidics still had an orderly triple helix structure.And EBG has that same characteristic peak as EBGS.(2)In this chapter,the Euglena?-glucan was degraded by electron beam irradiation,and the effects of different irradiation doses on the physical and chemical properties and structure of Euglena beta-glucan were analyzed by solubility analysis,particle size analysis,FT-IR,XRD and SEM.The results showed that the dissolved fraction of?-glucan(I-EBG)in Euglena after irradiation increased with the increase of absorbed dose.And the particle size and the particle size dispersion showed a trend of first decreasing and then increasing.FT-IR and XRD analysis show that irradiation can break the?-glycosidic bond of?-glucan molecules and then oxidize them into carbonyl groups.It can be seen from SEM that?-glucan molecules agglomerate with the increase of irradiation dose.(3)I-EBG was separated and purified by DEAE-52 cellulose column chromatography to obtain components I-EBG-1 and I-EBG-2,and I-EBG-1 and I-EBG-2 were further purified by dextran gel column chromatography.After purification,I-EBG-1 and I-EBG-2 had single components and high purity.I-EBG-1and I-EBG-2 have arabinose,rhamnose and galactose that EBG does not have.The weight average molecular weights of EBG,I-EBG-1 and I-EBG-2 are 6387,2730 and3839 Da,respectively.The infrared spectra of I-EBG-1 and I-EBG-2 show that I-EBG-2 has neither?-glycosidic bond nor carbonyl group formed by oxidation.(4)The experimental results of antioxidant activity of EBG,I-EBG-1 and I-EBG-2 showed that I-EBG-2 had significant effects on DPPH·and·OH clearance rate is obviously higher than I-EBG-1.I-EBG-2 versus O2-·compared with I-EBG-1,the scavenging rate and reducing ability are only slightly superior,but the overall antioxidant activity shows that I-EBG-2>I-EBG-1>EBG.It shows that irradiation treatment can improve the antioxidant capacity of EBG. |
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