Structure And Functional Properties Of Chinese Quince Seed Gum

Chinese quince seed gum was a kind of newly discovered natural hydrophilic colloid,which was a by-product of Chinese quince seed oil extraction.The existence form of Chinese quince seed gum was similar to flaxseed gum.After soaking the seeds at room temperature,a smooth and sticky colloidal solution was released on the surface.At present,the supply of natural hydrophilic colloid falls short of the demand because of its green,safe and non-toxic characteristics,so it was particularly important to develop new hydrophilic natural colloid resources.Chinese quince seed gum was a newly discovered hydrophilic colloid resource,but the basic structure and functional application properties of Chinese quince seed gum were very scarce,which greatly limited the application of Chinese quince seed gum in food,light industry and chemical industry.In this paper,the structure,functional properties and application of Chinese quince seed gum were studied.The main research contents and results are as follows:1.Chinese quince seed gum was derived from the surface of Chinese quince seed,and the extraction method was water extraction and alcohol precipitation.After extraction,the structure characterization and antioxidant activity of Chinese quince seed gum were studied.The results showed that Chinese quince seed gum was a heterogeneous heteropolysaccharide with narrow molecular weight distribution,the average molecular weight was 4.46×10⁵ Da,the protein content was 2%,the total sugar content was 68.25%,and the total aldehyde content was 31.6%.Its antioxidant activity in vitro is better than that of common food colloid:pectin,gum acacia and flaxseed gum.In this chapter,the overall structural characteristics and antioxidant activity of Chinese quince seed gum were studied for the first time,which provided a theoretical basis for the study of the function and application characteristics of Chinese quince seed gum.2.To explore the emulsification characteristics of Chinese quince seed gum under different gum concentration,Na Cl concentration and pH value of aqueous phase environment.Under the condition of higher CQSG concentration and neutral pH,the emulsion samples have smaller particle size,higher charge stability and lower air-water interfacial tension and oil-water interfacial tension,while the emulsion samples containing salt and acid were just the opposite.The heavy phase separation effect of the emulsion samples prepared by Chinese quince seed gum decreased gradually with the increase of the gum concentration.The emulsion samples with 0.3%and 0.5%CQSG(w/v)concentration were stored at 60?for 30days in the dark,and showed very stable performance without oil-water separation phenomenon.The final stability index of the Chinese quince seed gum emulsion samples with the concentration of 0.2?1.0 M of sodium chloride is about 60%,which was mainly represented by the precipitation of a large amount of free water.The emulsion prepared by Chinese quince seed gum was the most stable under the condition of neutral pH value,and the most unstable under the acidic condition of pH=5.This indicates that salt and acidic environment was not conducive to the stability of CQSG oil-in-water emulsion.When comparing the emulsification stability of Chinese quince seed gum with commercially used food hydrophilic colloid(pectin,acacia gum,guar gum and flaxseed gum),the gum concentration was 1.0%(w/v).Only the emulsion prepared by CQSG and flaxseed gum could be preserved for one month at 60?without phase separation.Therefore,CQSG was a promising new hydrophilic colloid emulsifier,whose emulsification stability was better than that of common natural food colloid,and it had potential application as emulsifier in food,medicine,cosmetics and other industries.3.The gel properties of Chinese quince seed gum were studied under different pH,sodium chloride concentration,calcium chloride concentration and complex phosphate concentration.The results showed that the structure,flow behavior,water holding capacity,Zeta potential and morphology characteristics of CQSG gel were significantly affected by different pH values,different salt ion types and concentrations.The cooling curve and reheating curve of DSC analysis showed a single exothermic peak and endothermic peak.The gelling temperature and melting temperature of CQSG gel were not affected by pH value and the addition of different types and concentrations of salt ions.The water holding capacity of CQSG gel firstly decreased and then increased with the increase of Na Cl and composite Ca Cl₂,and firstly increased and then decreased with the increase of pH and composite phosphate concentration.The effect of different salt ion types on the viscosity,absolute potential and gel strength of CQSG gel was consistent with the effect of water retention.These results indicated that the effects of different ions on CQSG gel can be promoted or weakened in a certain range.This law can be applied in industrial application of CQSG as a gelling agent to promote the gelling effect under reasonable ion concentration conditions.The melting point of Chinese quince seed gum was higher than the freezing point.It was a kind of thermally reversible cryogenic gel.The research results will provide impetus for its application as a new functional ingredient in food industry.4.Flax seed oil microcapsules were prepared with Chinese quince seed gum as wall material to evaluate the potential of Chinese quince seed gum as wall material for freeze-drying linseed oil microcapsules.Studies have shown that water-in-oil systems containing 40%and 50%flaxseed oil can observe 30-day storage without phase separation,while also showed smaller average droplet size and higher negative potential values.Chinese quince seed gum with smooth skin as wall material has obvious protective effect on flaxseed oil as the core of the microcapsule powder,40%of the microcapsule samples containing core at 60?for 30days can reduce the oxidation rate of up to 20%.The microcapsules prepared by freeze-drying have a typical porous fold structure.The results showed that Chinese quince seed gum could be used as a new type of microencapsulation wall material and could be used in food industry as a functional component of microencapsulated flaxseed oil.