Study On Extraction Of Chinese Quince Seed Oil And Structure And Application Characteristics Of Seed Polysaccharide

Chinese quince?Chaenomeles sinensis;family Rosaceae?is a small fruiting tree,native to China.Chinese quince is rich in polysaccharides,organic acids,phenolic acids,vitamins,triterpenes,including oleanolic acid,ursolic acid.Flavonoids that can effectively prevent oxidative damage caused by free radicals are also one of the main components in the fruit of Chinese quince.The dried Chinese quince fruit has been traditionally used in Chinese medicine to treat throat diseases,and its fruit liquor has been commonly added to lozenges to treat coughs and sore throats in Japan.At present,a large number of Chinese quince fruits are exported to Japan and Korea at low price.The extracts of Chinese quince fruits are often added to high-grade cosmetics.Recently,many attempts have been made to verify the antiulcer and antioxidant activities of fruit extracts from the Chinese quince.Typically,in processing quince fruits,the seeds are discarded.Therefore,investigations on Chinese quince seed will provide a fundamental basis for the further development and utilization of Chinese quince resource.The main research contents and conclusions are as follows:1.The high quality oil and defatted meal with a high protein content can be obtained by subcritical fluid extraction technology.Subcritical fluid?SCF?extraction is executed at lower pressures and temperatures than the pressures and temperatures used in supercritical fluid extraction.However,no studies on the SCF extraction of CQS oil are reported.Therefore,the objective of this study was to evaluate the use of SCF for the extraction of Chinese quince seed?CQS?oil and to compare the use of SCF with the classical soxhlet?CS?extraction and supercritical CO₂?SC-CO₂?extraction methods.Response surface methodology?RSM?was used to investigate the extraction conditions:temperature?45 ^oC-65 ^oC?,time?30 min-50 min?,and solvent/solid ratio?5 mL/g-15 mL/g?.The optimization results showed that the highest yield?27.78%?was obtained at 56.18°C,40.20 min,and 12.57 m L/g.The oil extracted by SCF had a higher unsaturated fatty acid content?86.37%-86.75%?,higher?-tocopherol content?576.0 mg/kg-847.6 mg/kg?,lower acid value?3.97mg/g?,and lower peroxide value?0.02 meq O₂/kg?than extractions using CS and SC-CO₂ methods.The SCF-defatted meal of oilseed exhibited the highest nitrogen solubility index?49.64%?and protein dispersibility index?50.80%?,demonstrating that SCF extraction was a promising and efficient technique as an alternative to CS and SC-CO₂ methods,as very mild operating conditions and an eco-friendly solvent can be used in the process with maximum preservation of the quality of the meal.2.In order to realize waste recycling of Chinese quince seed meal,the structure and antioxidant properties of polysaccharide from defatted meal were determined to provide a theoretical basis for further research and application of Chinese quince meal.In the present study,three polysaccharide fractions,QSMP-1,QSMP-2,and QSMP-3,were isolated and purified from the seed meal of Chinese quince.These fractions'structures were investigated by high performance anion exchange chromatography?HPAEC?,gel permeation chromatography?GPC?,Fourier transform infrared?FT-IR?,and nuclear magnetic resonance?NMR?,and their antioxidant activities were assessed.The results showed that QSMP-1 is a novel polysaccharide with a backbone mainly composed of?4)-Glcp-?1?,?6?-Glcp-?1?,?6?-Galp-?1?,?2,3,4?-Xylp-?1?.The side chains consist of?4?-Arap-?1?,?3,4?-Arap-?1?,?2?-Galp-?1?,?4?-Manp-?1?,?3?-Galp-?1?,and?3,6?-Glcp-(1?with the non-reducing terminals Glcp and Galp.QSMP-1 exhibited effective antioxidant activities by ferrous ion chelation and superoxide anion-scavenging in a dose-dependent manner.These investigations of the polysaccharides from the seed meal of Chinese quince provide a scientific basis for the use of the by-products of quince seed oil processing,particularly as an ingredient in functional foods and medicines.3.The physicochemical characteristics and functional properties of crude polysaccharide extracts from Chinese quince seed meal were determined and analyzed for discovering its potential in the food industry.This study investigated the water absorption property,oil absorption property,foam capacity,foam stability and emulsification properties of polysaccharides from Chinese quince seed meal.Different temperature?60°C,80°C,100°C?conditions were used to extract Chinese quince seed meal polysaccharide?CQSMP?and the three fractions were gradedly deproteined by the Sevage method.The droplet sizes and stabilities of emulsions of polysaccharides at different concentrations were measured.The results indicated that the protein content,foam capacity,foam stability of samples decreased,carbohydrate content,water absorption capacity and oil absorption capacity increased as the extraction temperature increased.In CQSP60,CQSP80 and CQSP100 fractions,as the deproteined time increased,the water absorption capacity,oil absorption capacity,carbohydrate content increased.CQSP60-3 and CQSP80-3 showed higher FC and FS when compared to all other tested crude polysaccharides,which indicated their promising application for improving functional properties in different food formulations.According to the emulsification of CQSP100 fractions,the effects of the solution concentration,deproteined times,storage time on mean droplet size were not significant.The mean droplet size was not the only factor on the emulsification of sample solution.The emulsification properties of CQSP60?2%and 6%?,CQSP60-2?2%and 4%?,CQSP60-3?2%?,CQSP80?2%?,CQSP80-3?2%?,CQSP100?2%and6%?,CQSP100-1?2%,4%,6%?,CQSP100-2?2%?,CQSP100-3?2%and 4%?were relatively good.CQSP60,CQSP60-2,CQSP60-3,CQSP80,CQSP80-3,CQSP100and its deproteined fractions could be as emulsifier used in food and non-food industries.Therefore,polysaccharides of Chinese quince could be utilized as a natural emulsifier.4.Chinese quince seed gum?CQSG?is a novel potential viscosifier or stabilizer with good storage stability.In this work,CQSG was extracted from the surface of Chaenomeles sinensis?Chinese quince?seeds,and purified by DEAE-Sepharose Fast-Flow and Sephacryl S-400 HR chromatography;three fractions were obtained?CQSG-1,-2,-3?.The main fraction?CQSG-2?was investigated by monosaccharide analysis,methylation and one-dimensional?1D?and two-dimensional?2D?nuclear magnetic resonance?NMR?experiments to determine its structure.Results showed that CQSG-2 is composed of arabinose?Ara?,glucose?Glu?,xylose?Xly?,galacturonic acid?Gala?and glucuronic acid?Glua?in a molar ratio of 4.0:0.3:15.2:4.2:3.8.?4-?-d-Xylp-1?and?2,4-?-d-Xylp-1?constitute the backbone in a ratio of 5.9:4.5,and the Arap-1?,?-d-GalpA-1?,?2-?-d-GlcpA-1?,?4-?-d-Glcp-1?,and?2,3,5-l-Araf-1?form the branched chain.The molecular aggregation of CQSG-2 with high molecular weight?Mw??1.4×10⁶ Da?was strong compared with CQSG-1 and CQSG-3.This is the first systematic elucidation of the structure of Chinese quince seed gum,and it provides the basis for developing applications for this gum in the food and pharmaceutical industries.5.Characterization of the rheological properties of Chinese quince seed gum?CQSG?is fundamental both to designing optimized products and to ensuring stability when using it in food production.In the present paper,the rheological properties of CQSG at different concentrations?0.1%,0.3%,0.5%,1%,2%and 3%?,temperatures?5°C,20°C,35°C,50°C,65°C and 80°C?and pH values?3,5,7,9and 11?,and with the addition of salt solutions?KCl,NaCl,MgCl₂ and CaCl₂?in different concentrations were characterized by using steady and dynamic shear experiments.The results demonstrate that all CQSG solutions presented Newtonian plateaus followed by shear thinning regions and exhibited a dependence on concentration over the range of the shear rate(0.01 s^-1-100 s^-1).The viscosities of the gum solutions decreased with the addition of any salt,with increase in temperature and at extreme pH values?3 and 11?.The effect of temperature was examined using the Arrhenius model.As gum concentration increased the activation energy decreased.Additionally at higher gum concentrations,thixotrophic behavior was stronger in that CQSG had the elasticity typical of a solid.This effect was described using the Herschel-Bulkley models.The stress and frequency sweep tests demonstrated a unique result in that the crossover frequency shifted to a higher value when the CQSG solution concentration increased.At 3%,the solution reached a gel-like state,and the deformation was primarily elastic and recoverable under non-destructive conditions.These results could be the basis for CQSG product development and quality control in order to realize its potential industrial applications.