Study On Curing Characteristics Of Coix Seed Based On Stabilization Treatment Technology

Coix(Coix lachryma-jobi)Seed is a high-quality miscellaneous grain resource featured by high edible and medicinal value,which is produced primarily in Guizhou Province,China.However,owing to its prolonged cooking time resulted from its hard and dense texture,it is difficult to cook with other grains,which brings inconvenience to family cooking.Stabilization treatment technology can change the starch pasting property and pore structure characteristic of Coix seed on the basis of its physical effects,and then improve curing characteristics of Coix seed,thereby promoting a wide application in grain processing.In this paper,three stabilization treatment technologies were applied for processing,including vacuum microwave treatment(VMWT),microcosmic thermal current resonance treatment(MTCRT),superheated steam treatment(SHST).The curing characteristics and improvement mechanism of stabilization treatment of Coix seed were studied,followed by comprehensive quality evaluation.The purpose of the study is to provide a potential theoretical basis for the application of stabilization treatment technology in the improvement of curing characteristics of Coix seed and to promote the development of Coix seed industry.The main content of this paper is as follows:(1)Study on curing characteristics and kinetics of Coix seed through stabilization treatment technologyA simulation test of curing was carried out in Coix seed underwent stabilization treatment to explore its curing rate,magnetic resonance imaging(MRI),curing ratio,moisture content,degree of starch pasting,hardness and volume expansion rate,etc.The correlation analysis and kinetics study were carried out subsequently,with results described below.The curing rate of VMWT reached the highest,besides,the moisture content and the degree of starch pasting were significantly correlated with each curing characteristic index(p<0.05).Furthermore,the Weibull model of moisture content and degree of starch pasting fitted well(correlation coefficient of 0.997~1.000),which can be regarded as possible predictors for curing characteristics.Meanwhile,the co-cooking validation test of Coix seed and rice showed that VMWT could achieve co-boiling and co-cooking,exhibiting better effect of improving curing characteristics.(2)Study on the mechanism of stabilization treatment for improving curing characteristics of Coix seedThe starch pasting properties of Coix seed were characterized by rapid viscosity analysis(RVA),differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The microcosmic appearance was observed under scanning electron microscopy(SEM),and mercury intrusion porosimetry(MIP)was applied for the first time to characterize the pore structure of Coix seed.The results showed that the increase of total pore surface area and micropore volume was the major reason for the increase of curing rate(extremely significant correlation,p<0.01).(3)Comprehensive quality evaluation of Coix seed underwent stabilization treatmentFor quality evaluation,a factor analysis(FA)was established by determining 21 indexes such as nutritional activity,curing characteristic,starch pasting property and pore structure of Coix seed underwent stabilization treatment,etc.Then,three common factors were extracted as "pore structure and curing characteristic factor","starch pasting characteristic factor","nutrient and active ingredient retention factor" for further comprehensive quality analysis.The results showed that the ranking order was VMWT,SHST,CK and MTCRT,among which VMWT had the best comprehensive quality.