| At present,the world's annual demand for pectin continues to increase at a rate of 15%,with a total demand of more than 30,000 tons.However,the annual productivity of Chinese pectin is very low,and it is only enough to provide domestic demand of 20%.According to reports in the literature,the content of pectin in Premna microphylla Turcz is approximately 15~30%(based on dry leaf),but it has not been fully utilized for a long time.In this study,SHMP and ammonium oxalate were used to extract pectin from Premna microphylla Turcz,and its technological conditions were optimized.The purity of Premna microphylla Turcz pectin was improved by the steps of decolorization and decolorization,and the preliminary study on its application in yogurt was made in order to be the capital of Premna microphylla Turcz.The comprehensive utilization of the source provides a theoretical basis.The main results are as follows:1.Using SHMP as an extractant,auxiliary ultrasonic extraction,single-factor experiment and orthogonal test,the best ultrasonic power of Premna microphylla Turcz pectin was 100 W,extraction temperature 70°C,extraction time 70 min,SHMP mass concentration 17.5g/L and material The liquid ratio was 1:50g/mL,and the yield of pectin under this condition was 87.57%.However,compared with the ultrasound-assisted ammonium oxalate method used in the laboratory,SHMP ultrasound-assisted extraction method is higher than the ammonium oxalate extraction method,but its purity is only 25.56%,and it is difficult to desalination.2.The decolorization effects of the extracts of pectin were compared using activated carbon,X-5 macroporous resin,AB-8 macroporous resin,diatomaceous earth,and 30% hydrogen peroxide,respectively,to determine the decolorization rate and the yield after purification,these two items as evaluation indicators,the results showed that the decolorization rate and the yield after purification of activated carbon were all relatively good,the optimum process parameters for optimized decolorization of activated carbon were activated carbon 1.2g/100 mL pectin extract at a temperature of 40? for 30 minutes.The decolorization rate of pectin was 56.83% and the yield after purification was 87.44%.3.When using alcohol washing method to remove sugar,the removal rate of soluble sugar was 98.87%,and the yield after purification was 83.15%.The effect of degumming by dialysis was worse,the removal rate of soluble sugar was 94.33%,and the yield after purification was 84.48%.4.The crude pectin obtained by the ultrasonic-assisted extraction of ammonium oxalate had a purity of 66.48%.On this basis,after decolorization and purification,the purity of Premna microphylla Turcz pectin was 86.63%.The ash,drying weight loss and other indicators of the colloidal plasticity of the purification process have all decreased,and the main indexes of the two pectin have reached the light industry standard(QB2484-2000).5.The yoghurt was made from purified Premna microphylla Turcz pectin,commercial cellulite pectin and Carboxymethylcellulose sodium as a thickener,and the viscosity,water holding capacity,color and sensory indexes of the made yogurt were measured and evaluated.The results showed that the water holding capacity of yogurt with the thickener of Premna microphylla Turcz pectin thickener was significantly better than the other two,and the viscosity was between two,but the color and lustre was slightly worse than that of the yogurt with the orange peel pectin.At this time,the yoghurt was delicate and smooth at the entrance.Sexuality is better than the other two,and there is no significant difference in yogurt's unique milk flavor,sweet and sour taste,etc. |
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