Study On Extraction,structure And Functional Application Properties Of Chinese Quince Seed Gum

Chinese quince（Chaenomeles sinensis）belongs to the Rosaceae family.Chinese quince is different from the widely known papaya（Carica Papaya L.）.Papaya belongs to papaya family,papaya genus plant.Papaya can be eaten directly and its ripe fruits can be used as fruit.However,mature Chinese quince fruit is highly lignified and still contain more tannins and organic acids,which has a sour,woody taste and can only be used for jams,juices and preserves after processing.A large amount of seeds produced during the processing of Chinese quince fruit,which is a potential raw material for edible oil production.During the pre-treatment process of oil production,a large amount of water-soluble gum by-products,namely Chinese quince seed gum,is dissolved on the surface of Chinese quince seeds.How to efficiently exploit this by-product of Chinese quince seed oil production process is of great importance to improve the value of the whole Chinese quince seed processing industry.According to the understanding,the selection and optimization of the dissolution conditions for Chinese quince seed gum have not been covered.In order to realize the efficient dissolution of Chinese quince seed gum and continue to expand the application of Chinese quince seed gum,the main research contents of this study are as follows:1.The structural and functional properties of Chinese quince seed gum extracted under different temperature and p H conditions were investigated.The results showed that the yield of Chinese quince seed gum was low under acid or alkaline conditions,and the yield was the highest under neutral environment of 80°C,but the emulsification stability was the worst.The sample extracted at 50°C had the best emulsion stability and higher free radical scavenging ability.With the increase of extraction temperature,the samples contained a small amount of protein components.The molecular weight of the quince seed gum was higher under neutral or acidic extraction environment,and lower in alkaline extraction environment.The rheological properties of the samples extracted under neutral condition were better than those under alkaline condition.In general,Chinese quince seed gum extracted from neutral environment at 50°C showed high emulsifying stability and antioxidant activity,and stable rheological properties,which showed excellent application potential as natural antioxidant,emulsifier,stabilizer and other additives.2.The functional properties of Chinese quince seed gum were investigated under different drying methods.After drying,the samples dried under oven-dried at 105°C had the brightest appearance with the darkest red color and were restricted to use only in products such as sausages.The solution of sample dried under oven-dried at 50°C has higher stability and the best emulsification property.Vacuum-dried sample solution has poor stability and worst emulsification stability.Except for the samples dried by oven-dried at 105°C,the foaming ability of the samples under other drying conditions was weakened.The foam stability of samples obtained by oven-dried of 50°C and oven-dried of 105°C is better.The results showed that suitable drying methods could be selected based on different functional characteristics of Chinese quince seed gum.3.The functional properties of Chinese quince seed gum were investigated under different freeze-thaw conditions（-18°C,-30°C）.After freezing and thawing,the consistency coefficient（K）,flow resistance and viscosity of Chinese quince seed gum solution increased.The hardness,elasticity,cohesiveness,chewiness and emulsification ability were improved,and the ability to form network structure of gum was enhanced,and the characteristic change of high concentration sample solution（1.0%w/v）was more obvious.After freezing and thawing,Chinese quince seed gum can effectively slow down foam instability,and the hydrogen bond interaction remains stable,which has the ability to inhibit ice crystal growth.These results indicate that Chinese quince seed gum can protect frozen foods and desserts from structural damage after dehydration,and has the potential to be used as a frozen protective agent to protect the shape of food,and has the potential to be further applied in frozen foods such as ice cream,frozen desserts,surimi and meat products.4.The low molecular weight oligosaccharide was prepared from Chinese quince seed gum by hydrogen peroxide oxidation method and its antioxidant activity in vitro was studied.The results showed that when H₂O₂ concentration was 0.3 mol/L,reaction temperature was120°C and reaction time was 2.0 h,the highest yield of oligosaccharides was 17.6%.The monosaccharide of the oligosaccharide is mainly composed of xylose（61.0%）and arabinose（16.2%）,and the molecular weight of arabinose is 1774 Da.It has strong water absorption and high free radical scavenging ability（DPPH free radical:88.3%,hydroxyl free radical:94.7%,ABTS⁺free radical:86.1%,DMPD⁺free radical:82.5%）.The results showed that Chinese quince seed gum could be oxidized by H₂O₂ to produce a natural arabinoxylan,which could be used as a natural antioxidant or functional oligosaccharide in food and non-food industry.In summary,the study showed that the selection of extraction temperature and drying conditions not only help to obtain Chinese quince seed gum with good functional application properties,but also help to obtain stable solution dispersion system;Chinese quince seed gum has potential as cryoprotectant;oligosaccharides obtained by oxidant（H₂O₂）treatment with Chinese quince seed gum as raw material have high antioxidant activity.This study not only provides a basis for the extraction and drying conditions of Chinese quince seed gum,but also provides a theoretical and technical basis for its further application in food industry.