The Preparation Of Mung Bean Hull Nanocrystalline Cel Ulose And Its Application In Edible Films

Due to the energy crisis and environmental pollution, the use of renewable biological resources and edible packaging materials research gets more and more attention of people. This article was about the ultrasonic microwave-assisted alkaline extraction of cellulose from the mung bean hull-the waste of mung bean product, the preparation of mung bean hull nanocrystalline cellulose which had a high degree of crystallinity, strength and large specific surface area, and the study on the shape size and microstructure of nanocrystalline cellulose. To improve the mechanical properties and the barrier performance of whey protein concentrate films, made the mung bean hull nanocrystalline cellulose blended with whey protein concentrate to prepare the edible film. The study can provide a reference for the abandoned mung bean hull recycling and the further development of edible packaging materials.Specific contents and conclusions are as follows:(1) Study on the extraction and its properties of mung bean hull celluloseCellulose was extracted from mung bean hull by ultrasonic microwave-assisted alkaline extraction. The paper analyzed the effects of five factors on the yield, swelling capacity and water holding capacity of mung bean hull cellulose. These factors were the mass fraction of Na OH, the addition of Na OH, ultrasonic microwave synergy time, microwave power and decoloring time. Conclusion: ultrasonic-microwave assisted alkaline extraction could improve the yield of mung bean hull cellulose and its physical and chemical properties more effectively; According to the single factor experiment results, the optimal technology parameters were the mass fraction of Na OH 10%, the addition of Na OH 15 m L/g, ultrasonic microwave synergy time 15 min, microwave power 300 W, decoloring time 90 min; and under the conditions, the yield of mung bean hull cellulose was 44.91%, the swelling capacity was 4.01 m L/g, and the water holding capacity was 7.16 g/g. The infrared spectrum analysis results showed that the characteristic peak of mung bean cellulose extracted by alkali with ultrasonic microwave-assisted had no obvious change and the cellulose had less residual lignin, no destruction in crystal structure of mung bean hull cellulose and could effectively improve the mung bean hull cellulose crystallinity.(2) Study on mung bean hull nanocrystalline cellulose preparation and its performanceThe mung bean hull cellulose was used as raw material to obtain nanocrystalline cellulose by sulfuric acid hydrolysis. Studied the effects of sulfuric acid concentration, acid solution time and acid solution temperature on the yield of mung bean hull nanocrystalline cellulose. At the same time, analyzed the microstructure, spectral properties and crystal structure of mung bean hull nanocrystalline cellulose. Conclusion: The best process conditions for Mung bean hull nanocrystalline cellulose was that sulfuric acid concentration 64.15%, acid solution temperature 45.43 ℃, acid solution time 1.52 h. Under the conditions, the average yield of mung bean hull nanocrystalline cellulose was 18.13%; The mung bean hull cellulose nanocrystals presented a rod-shaped nature with the length ranging from 100 to 200 nm and the diameter ranging from 10 to 20 nm; According to the mung bean hull nanocrystalline cellulose infrared spectrum analysis and X-ray diffraction analysis, during the preparation of the mung bean nanocrystalline cellulose, it keeped the typical cellulose structure and improved its crystallinity.(3) Study on mung bean hull nanocrystalline cellulose-whey protein concentrate edible films preparation and its performanceBy single factor tests and the response surface optimization tests, studied the effect of mung bean hull nanocrystalline cellulose content, concentrated whey protein concentrate and glycerin content on the mechanical properties, the barrier performance and transmittance of the edible films. Conclusion: The best process conditions of the preparation for edible films was that mung bean hull nanocrystalline cellulose content 1.93%, the concentration of whey protein concentrate 9.20% and glycerin content 5.93%. Under the conditions, the elongation at break was 120.50%, the tensile strength was 2.32 MPa, the oxygen permeability was 0.60 cm3/(m2·d·Pa), the water vapor permeability was 2.41 g/(cm·s·Pa), the transmittance was 41.61%; According to Mung bean hull nanocrystalline cellulose-whey protein concentrate films infrared spectrum and scanning electron microscopy analysis,we knowed that the right amount of mung bean hull nanocrystalline cellulose blended with whey protein concentrate was relatively uniform, and the compatibility is well.