Effects Of Plasma Treatment On The Structural And Functional Performance Of KGM

Konjac glucomannan(KGM)is a kind of natural renewable polymer,the film made of KGM has advantages of well filmed,edible and biodegradable,and is with broad prospect of application and high value for study in food and medicine field.To improve the surface properties of the KGM film and expand the application field,plasma surface modification processing on KGM membrane was did,and the effects of plasma treatment on the structure and film performance were studied.Preservation research of the modified KGM film on broccoli was also conducted.The main research contents and conclusions are as follows:1.The changes of KGM structure after plasma treatment were analyzed.UV,IR and Raman spectrum showed that nitrogen groups appeared,part of the KGM molecular chain fractured,the number of the hydrogen bonding increased,and there was no obvious change in the main body of the molecular chain and main functional group.The X-ray scan showed that crystallization area and ordered arrangement both increased,but overall remained amorphous and non-crystal forms.The XPS analyses indicated that the main distribution of nitrogen ions implanted was in 0?50nm depth,surface atomic concentration ratio(wO/wC)increased.The energy of the plasma conduced surface oxidation and glycosidic bond break,part of acetyl felled off and ammonia displaceed part of hydroxyl.The DSC results indicated that there was no obvious change with thermodynamics performance.2.The membrane performance of KGM before and after plasma treatment was compared,the mechanics performance of tensile strength and breaking elongation was improved.Tests of surface contact angle,solubility and hygroscopic showed that the whole KGM membrane hydrophilic reduced,and it presented a certain resistance to water.WVP value and luminousness were both reduced.3.The storage experiment on broccoli with the modified membrane was conducted.the results showed that modified membrane could better maintain the sensory index of broccoli and prevent moisture loss.It also had good effect on the maintaining of nutritional value(vitamin C,chlorophyll and soluble solids content).The broccoli with modified membrane had less physiological activity variation,the largest gap of cell membrane permeability was in the 3 day,in the early storage the POD expressed difference,but CAT was mainly in the later period,there was significant variation of MDA from the second day.