Study On Extraction, Purification And Properties Of β-glucan From Oat

Oat is rich in protein, vitamins, phenols and β-glucan and they have a high nutritional value. The content of β-glucan in Oat is from3%to7%. Oat P-glucan has lowering of cholesterol, regulation of blood glucose levels, proliferating of intestinal probiotics, regulation of immune and other physiological functions. In addition, it also is applied in salad dressings, ice cream and non-fat yogurt and plays an important role in food system.Because of good properties of Oat P-glucan, research about β-glucan is hot in a academic field.In this paper, oat was used to extract β-glucan and the extraction, purification, properties of β-glucan from oat were studied. The results were as follows:1. In the extraction processing, the effect of water extraction method and ultrasonic extraction method on oat β-glucan yield was compared and analyzed. The optimal extraction conditions by single factor and orthogonal experiment were determined.The results showed that the optimal extraction conditions by ultrasonic method were as follows:the ratio of water to material20:1, the ultrasonic power720W, the pH10, the ultrasonic time35min and the temperature50℃. And the optimal extraction conditions by water method were as following:the temperature80"C, extraction time3h, the pH11, the ratio of water to material25:1. By comparison of β-glucan yield between by water method extraction and by ultrasonic treatment extraction, optimal method was ultrasonic treatment.2. The extraction liquid of P-glucan by ultrasonic treatment contained starch, protein and pigment. The process for the removal of starch by starch enzyme method was optimized as follows: enzyme dosage4U/g oat, reaction time10min. The optimal process for the removal of protein was trypsin-isoelectric point method, the removal rate was up to90.8%, the retention rate of β-glucan was90.42%. The process for decolorization by active carbon method was optimized as follows: amount of active carbon2%, the decolorization temperature40℃, time40min. The process for decolorization by AB-8resin method was optimized as follows:temperature40℃, time80min, amount of resin15g/100mL sugar liquid. By comparison of two kinds of decolorization agent, the results showed that decoloration rate of AB-8resin was the highest and up to55.27%, the retention of β-glucan was the highest, and up to90.69%. Thus, AB-8resin was as bleaching agent.The process of β-glucan precipitation by ethanol method was optimized as follows:ethanol concentration60%, ethanol precipitation time20h. The component of products by ultrasonic treatment extraction was analyzed.3. The viscosity of oat β-glucan solution was affected by mass percent concentration of β-glucan and NaCl, temperature and pH. With the increasing of mass percent concentration of β-glucan, the viscosity of solution was increasing. With the increasing of mass percent concentration of NaCl and temperature, the viscosity of solution was decreasing. When pH was from3to7, with the increasing of pH, the viscosity of solution was increasing. When pH was from7to11, with the increasing of pH, the viscosity of solution was decreasing.4. The water-binding capacity of oat β-glucan was affected by temperature, pH and NaCl mass percent concentration.With the increasing of mass percent concentration of NaCl, the water-binding capacity of oat β-glucan was decreasing. With the increasing of temperature, the water-binding capacity of oat β-glucan was increasing. Under acidic condition, with the increasing of pH, water-binding capacity was increasing. Under the alkaline condition, with the increasing of pH, water holding capacity was decreasing, but the change was not obvious.5. The foam and emulsion capability and stability of oat β-glucan was affected by β-glucan mass percent concentration, pH and temperature. With the increasing of mass percent concentration of β-glucan, foam and emulsion capability and stability was increasing. When temperature was from25℃to45℃, with the increasing of temperature, the foam and emulsion capability and stability of oat β-glucan was increasing. When temperature was from45℃to100℃, with the increasing of temperature, the foam and emulsion capability and stability of oat β-glucan was decreasing. Under acidic condition, with the increasing of pH, the foam and emulsion capability and stability was increasing. Under the alkaline condition, with the increasing of pH, the foam and emulsion capability and stability was decreasing.