Extraction,Purification And Substation Of Polysaccharides From Medemia Argun Fruits And Its Microcapsules Applied Research

Argun palm(Medemia argun)is a type of African fan palm native grown in the Nubian Desert Oases of Egypt and Sudan with ambiguous history.Its prevalent Bedouin name is argun palm and Nubian Desert Palm.This palm was once more widespread but is now restricted in the River Nile's upper valley in Egypt and Sudan.Argun fruits are usually of medium size,globose with a large stone kernel covered by fibrous and sweet flesh covered by a purple-black smooth,fragile peel.This research was conducted to investigate the nutritional composition of the argun palm fruit,Moreover,extraction,purification,and characterization of the polysaccharides from the fruit flesh.Besides the application of Argun fruit polysaccharide(AFPS)as a novel encapsulation wall material and find out the best AFPS based formulations for producing tea polyphenols(TP)microcapsules and Citrus aurantium L.essential oil(CAEO)microcapsules and study their stability.The significance of this study lies in that it is the only systematic study that covered the physicochemical,nutritional,antioxidant,and functional properties of Peel,Flesh,and Kernel of the Argun fruit.Moreover,production AFPS as a novel encapsulation wall material alternative to gum arabic and maltodextrin and applied it successfully to encapsulate the Citrus aurantium L.essential oil and tea polyphenols.Firstly,this study investigated the nutritional,chemical compositions,and functional properties of argun palm fruit because there is no research on the Sudanese variety of this palm.Flesh,peel,and kernel of argun fruits were analyzed based on their dry weight.The argun fruit analysis showed that its fruit had 54.85%dry weight(dwt)carbohydrate,13.25%dwt fiber,2.47%dwt Protein,0.86%dwt fat,and 0.01%vitamins.Argun peel had the highest phenolic content(43.76 mg gallic acid equivalent/g dwt)with the higher antioxidant activity in terms of DPPH·IC50(0.49 mg dwt)and ABTS·+radical cation(69.48 mg Trolox equivalents/g dwt).There were significant differences among all argun fruit parts in terms of the functional properties.In conclusion,the argun fruit is a good source of carbohydrates.Secondly,in this work,crude AFPS was extracted from the dry flesh of argun palm fruit with hot water in ratio 1:20 w/w and deproteinized by four different methods,namely HCl,TCA,Na Cl,and Ca Cl₂.The extraction yield of crude AFPS was 20%,and the polysaccharides content of the crude AFPS was 72%.The deproteinization percentage of samples treated with HCl,TCA,Na Cl,and Ca Cl₂methods were 59.62,58.03,89.47,and 62.52%,respectively;at the same time,polysaccharides loss during this step was 7.15,4.25,18.16,and 25.69%,respectively.Depending on these findings,the Na Cl method was chosen as the suitable deproteinization method.Furthermore,the AFPS(Na Cl method)was purified with on Sephadex G200 gel column eluted by distilled water at a flow rate of 0.5 m L/min,then the characteristics of obtained pure AFPS were measured.The purification yield was 80%,the purity of AFPS was 96.2%,and its molecular weight was 4.46×105 Da.The polysaccharide from argun palm fruit consisted of2.05%fructose,4%arabinose,36.2%rhamnose,29.15%galactose,3.15%glucose,7.55%xylose,and 17.9%galacturonic acid,these sugars were linked by the?-glycosidic bonds.The thermal properties and antioxidant activity of pure AFPS were investigated by Differential scanning calorimetry(DSC),Thermo-gravimetric analysis(TGA),DPPH·assay,ABTS·+assay,and FRAP assay.The result of TGA and DSC indicated that AFPS has good thermal stability.The DPPH·IC₅₀ and ABTS IC₅₀of studied AFPS were 5.17 mg/m L and 13.61 mg/m L;in addition,AFPS showed good Fe-reducing power.Depending on antioxidants experiments,it was clear that AFPS possessed high antioxidant activity,and It has potential applications as a natural antioxidant.Thirdly,polysaccharides are regarded as promising biopolymers for encapsulation and delivery of food-derived bioactive ingredients because of their molecular structure.The target of this part was to evaluate the influences of the partial replacement of the maltodextrin(MD)as typical wall material by AFPS as a new promising wall material in the microencapsulation of CAEO.MD replaced with AFPS at 0%,25%,50%,75%,100%.The emulsions properties,yield,microencapsulation efficiency(MEE),structural and physicochemical characteristics,TGA,Glass transition temperatures by DSC,crystallinity,oxidative and antioxidant stability of the freeze-dried CAEO microcapsules were investigated.The highest values of viscosity and droplet size were achieved by CAEO emulsion stabilized with wall material formulation,in which the replacement rate was 100%.The yield and MEE of CAEO microcapsules were significantly enhanced with increasing of AFPS in the formulations.The partial replacement treatments by AFPS increased solubility,bulk density,tapped density,particle density,and porosity of the obtained microcapsules.FTIR,X-ray,DSC,and TGA techniques confirmed that the encapsulation of CAEO was perfectly successful.The replacement of MD with AFPS improved the oxidative stability and antioxidant activity of microencapsulated CAEO during storage.Depending on physicochemical properties,thermal stability,and antioxidant activity,it could be considered that these microcapsules have promising applications in the functional food and medicine industry.Fourthly,the objectives of this work were to prepare TP microcapsules loaded in single gum arabic(GA),single AFPS,and their complexes in different ratios(GA/AFPS 1:3,GA/AFPS1:1,and GA/AFPS 3:1)using a freeze dryer and evaluate the influences of these carrier agents combination on the physicochemical,structural,antioxidant activity,and storage properties of the microcapsules.This study showed that the encapsulation efficiency and yield of TP microcapsules were increased by increasing AFPS in coating mixtures.TP microcapsules coated with GA/AFPS 1:3 had the highest encapsulation efficiency and yield than microcapsules coated with GA,AFPS,and other mixtures.The particle morphology of each microcapsule became smoother when the concentration of AFPS was increased.FTIR,X-ray,and DSC confirmed the success of the encapsulation process in this work.Their analysis showed that the TP was perfectly encapsulated and had good crystallinity and thermal stability.Microcapsules coated with GA,AFPS,and their complexes showed higher stability with the lower release of encapsulated TP when stored at 4 and 25°C for 28 days.Moreover,microcapsules coated by GA/AFPS 1:3 showed the highest antioxidant activity and capacity.It could be considered that these microcapsules have promising incorporation in medical products and functional foods.