Preparation Of Polysaccharides Film And Dynamic Monitoring Of Film Formation Process And Film Pilot Scale Process Research

In this thesis,a dynamic monitoring film forming device was designed,and polysaccharide membrane fluid was cast on the membrane disk of the device,and the near-infrared technique was used to dynamically monitor the membrane drying process,and the uniformity of the dried film was evaluated based on results of membrane thickness.The film casting machine for pilot experiment was designed and customized,and was used to investigate the formula for konjac glucomannan(KGM)film preparation and corresponding manufacturing process for pilot experiment.The produced KGM film in pilot experiment was applied in seasoning packaging of instant noodle,and the storage experiment was carried out.The main conclusions were obtained as follows:(1)The pullulan solution was cast on the membrane disk of film forming device.At the initial stage of drying(0 h),the near infrared reflectance spectrum of the points on the inner ring,middle ring,and outer ring of membrane solution were overlapped,in consistent with the uniform status of the pullulan solution;after drying for 2.5 h,the near-infrared reflectivity of the pullulan membrane solution was gradually decreased from the outer ring to the inner ring,in consistent with the drying process of the membrane fluid from the outer ring to the inner ring;after the film drying was finished(5 h),the near-infrared reflectivity of the outer ring was slightly higher than that of the middle ring,and the near-infrared reflectivity of the middle circle was slightly higher than that of the inner ring,this may be due to the slight shrinkage of the membrane to the center during the drying process,resulting in higher film thickness in the center than the edge of the film.The uniformity of the films prepared by dynamic monitoring film forming device was measured,and the film thickness at all points did not have significant differences.(2)The optimized formula for KGM was: KGM/water ratio 1.25%(w/v),glycerol addition 25%(w/w)based on the mass of KGM.The optimized KGM film manufacturing condition for pilot experiment was: casting thickness 2 mm,drying temperature 60 °C,and the ventilation speed 25 HZ.The corresponding film produced under the optimized formula and manufacture condition was flat and uniform,with tensile strength 84.3 MPa,breaking elongation 63.9%,and transparency T value 0.014.(3)The quality and appearance of the seasoning bag(seasoning powder,dehydrated vegetable,sauce)packaged by KGM film did not have significant changes after 6 months storage,and compared with the seasoning bad packaged by plastic bags,no significant difference was observed between the total number of microorganisms in both packages,and the total number of microorganisms in the seasoning powder package is about 120 cfu / g,the total number of microorganisms in the dehydrated vegetable bag is about 450 cfu / g,the total number of microorganisms in the sauce bag is about 350 cfu / g,and thus all results were less than 1000 cfu / g,fitting the requirement in national food safety standards...