Studies On Main Qualities Of Coix Lachryma-jobi Kernel Resources Of China And Activative Coixan

To evaluate the qualities of nutrition,healthy and for processing,thirteen species of Coix lachr yma-jobi kernel specimens were collected from twelve representative growing districts over China,where are from north latitude 20°to 48°.Based on the first phase study,the extracting and purifing technologies of Coixan from Fujian Jinsha Coix lachr yma-jobi kernel,with high amylose content,was focused on and had been systematically investigated,as well as the molecular structure,the physics and chemistry,and functional characteristics of Coixan..The main results were as follows:(1) Evaluation of the main qualities of Coix lachryma-jobi kernel resources in ChinaThe studies showed that the nutritional components in Coix lachr yma-jobi kernel suited the nutrient balance well,for the average contents of the nutritional components in Coix lachryma-jobi kernel were 15.80%protein,5.49%fat,63.05%carbohydrate,1.75% fibre,and 1.68%ash.Compared with rice or flour,Coix lachy ma-jobi kernel contained more protein and fat,but less carbohydrate.It is indicated that the Coix lachr yma-jobi kernel was rich in calcium,which was much more than that in rice and flour.The average contents of the VB₁,VB₂,VB₆,Fe,Zn,Se in Coix lachryma-jobi kernel were as much as that in rice and flour.The results of the amino acid analysis showed that the contents of the Glu,Leu, (Met+Cys) in Coix lachryrna-jobi kernel(accounting for 45.86 mg/g,21.71 mg/g,5.92 mg/g,respectively) were higher than that in the rice and flour,however,the content of Lys was less.According to ASS,Lys was the first limiting amino acid,and then,the second limiting amino acid was varied from the growing districts.For example,the second limiting amino acid of Coix lachryma-jobi kernel which from Yunan was Thy,from Sichuan was lie and from Guizhou was Val.The average of EAA/TAA and EAA/NEA were 35.86%and 55.91%.The average of EAAI was 58.91%.Compared to the FAO/WHO mode,the composition of amino acid of the protein in Coix lachr yma-jobi kernel was perfect,and the protein of Coix lachr yma-jobi kernel was considered as high quality protein.The study of healthy and processing qualities proved that Coix lachr yma-jobi kernel was an excellent economic crops which is served as food and medicine.Coix lachr yma-jobi kernel contains abundant Coixenolide,Coixan and total triterpenes,and their average contents were 44.60 mg/g,59.03mg/g and 22.83 mg/g,respectively.Coix lachryma-jobi kernel was a kind of starchy foodstuff,with 56.42%starch totally,and 4.78%amylase.Its healthy and processing qualities were closely related to the species and growing districts.This study originated the qualities research of Coix lachr yma-jobi kernel in China, and would provide an valuable reference for comprehensive utilization of Coix lachr yma-jobi kernel resources.(2) Kinetics for Coixan extractionIn a hot water extracting system,the mass transfer rates of Coixan were studied by varying the processing parameters,namely the extracting temperature(T),pH value,mass ratio of material vs water(R).The results showed that:â‘ The extracting temperature(T),pH value,mass ratio of material vs water(R) influenced Coixan saturation concentration(C^*) and Coixan saturation constant(K_sat) significantly(p＜0.01).â‘¡Through the three factors quadratic-rotation-interchangeable-composite experimental design,the empirical mass transfer models of C^* and K_sat with the parameters of the extracting temperature(T/℃),pH value,mass ratio of material vs water(R) were established.C^*×10³=47.2-1.17R-3.70T+75.38pH+0.054R2+0.050T2-6.38pH2(AOD)K_sat×10³=-1.13+5.27R+17.14T+222.4pH-0.027R.2-0.1T2-12.73pH2+0.017RT -0.1.7R pH(1/h)Results from experimental tests fitted the models well.(3) Optimization of the technology on deproteinization of CoixanThe removal efficiency of enzymatic deproteinization from Coixan was better than that of the sevag method or the trichloroacetic acid method.Through the rotating perpendicular combination experimental design,the parameters of enzymatic deproteinzation from Coixan were optimized,and the dynamic equation of deproteinization from Coixan was given.The results showed the optimal enzymatic deproteinzation conditions from Coixan were:the enzymatic temperature 45℃,pH 7.0,papain dosage 5000μ/g,thus,the percentage of the removed protein(PRP) went up to 80.12%.Moreover,if enzymatic deproteinization were combined with the sevag method,The protein could be removed from Coixan completely.(4) The physics and chemistry characteristics and molecular structure of CoixanCoixan,isolated and purified with Sephadex-75,was a milk white,flocculent powder, dissolves in water readly,was neutral polysaccharide with pH 6.8,thermal stability at 0℃～100℃,and more stable in acid than in alkaline stability among the food processing pH value.However,under strongly acidic and alkali conditions,Coixan was less stable in acid than in alkali.The results of color reaction indicated:Reacting with phenol-sulfuric acid reagent,anthrone reagent,Coixan turned into blown and blind green, respectively.However,it turned out to be colorless while reacting with I₂-KI,FeCl₃, carbazole- sulfuric acid reagent,fehling reagent and Coomassie BrilliantG-250 reagent.Furthermore,HPGPC and UV were employed to analysis the molecular characteristics of Coixan.Results showed that Coixan was a pure polysaccharide compound, without protein or nuclnic acid,with 2933molecular weight,specific rotatory power[α]²⁰D =+155°(0.151,H₂O),and inherent viscosity[η]=0.313.Molecular structure and surface morphology of Coixan were observed and analyzed by X-ray diffraction(XRD),Infrared spectrum(IR),Nuclear Magnetic Resonance(NMR) and Atomic Force Microscopy(AFM).According to XRD,Coixan wasn't a crystal.But according to IR or ¹H-NMR,Coixan was a hetero-polysaccharide without sulfonic group,but with acetyl group.The polysaccharide was probablely composed withα-D-xylose,α-D-glucose,β- D- alactose,β- D- mannose andβ- L- arabinose,and with theβglycosidic bond.AFM observations found that Coixan dispersed readly in water,the molecular took on the shape of a helix or liner structure with little round particles,blame-like protuberance, diameter about 40.0 nm-50.0nm,and height about 0.880nm-1.551nm.(5) The antioxidant activities in vitro of CoixanUsing crude and pure Coixan as materials respectively,the scavenging capacities on superoxide anion(O₂^-.),hydroxyl radical(·OH),1,1-diphenyl 2-picrylhydrazyl radicals (DPPH·) and the reducing power were tested with Fenton system,Pyorgallol Autoxidation Method,DPPH·system,and FRAP Method respectively.In addition,Ferrozine was employed as a reagent and indicator of Fe²⁺,to observed the chelating efficiency of Coixan with metal ions.The results proved that Coixan was a great proton(H·) donor,and had strong power to scavenge free radicals and readly chelating with metal ions.Moreover,pure Coixan had more power to scavenge free radicals and O₂^·.than crude one.The studied revealed that Coixan was a multipurpose inhibitor for free radicals and metal ions,thus the possibility to develop the anti-free radicals healthy functional food with Coixan would be avaiable.(6) The antioxidant and immune regulation effects of Coixan in vivo on miceAcute tetrachloride-intoxicated mice model was established by ip 0.2mL 0.2% tetrachloride(CCl₄).Compared with V_E as Positive control group,the mice were given with different doses of pure Coixan 250,500,1000mg/kg and crude Coixan 250,500,1000mg/kg pretreated ig by 0.5mL each day respectively for 28d.Blood SOD and GSH-Px activities, the content of GSH and serum T-AOC were detected as the marker of the oxidation resistance activity:and the activities of liver GOT,GPT and liver index were also detected.The results showed that comparing with model group,Coixan could significantly enhance blood SOD and GSH-Px activities in mice,prevent acute liver from CCl₄ effectly,and significantly inhibit the rising of liver GOT,GPT activities and the content of MDA.There are obvious dose-effect relationship of physiological activities for Coixan,and the effect of pure Coixan was better than that of crude one.The immune suppressive mice mode was established by ig Cyclophosphamide, Compared with saline as the normal control,the immune organs index,half of hemolytic value(HC₅₀),peritoneal macrophage phagocytosis index and the effect of lymphocyte proliferation were determined to observe the immune regulating effects of Coixan on mice immune system.The results showed that Coixan can significantly inhibit the reduction of the thymus and spleen indices of mice with lower immune function,enhanced the macrophage phagocytosis index and lymphocyte proliferation,raised serum HC₅₀,and corrected immune disorders phenomenon.Coixan could significantly improve the anti-oxidation function of tetrachloride-intoxicated mice,and had a great immune regulation activities on mice with immune suppressive.The mechanism is probably mediated with Coixan being a great proton(H·) donor,which had strong power to scavenge free radicals,to enhance the activities of anti-oxidation enzyme and the content of GSH,and to prevent lipid peroxidation.