| It is well known that pectin is one of the main components of primary cell wall and inner cell layer in higher plants,and it is a complex polysaccharide.Pectin owns some properties,for example,natural,environmental and low price,as well as antioxidation,antiglycation,anti-tumor,hypolipidemic and other biological activities,as a consequence,it can be used as a kind of natural food additive to reduce the loss of food quality and nutritional value,improve the quality of food,and reduce a series of Chronic non-communicable diseases.In this study,hawthorn was used as raw material to extract pectin by using ultrasonic method,enzymatic method,and hot water method.After decolorization and deproteinization treatment by macroporous adsorption resin D3520 and polyamide,the yield,total sugar content,galacturonic acid content,total phenol content,sulfuric acid group content,esterification degree were determined,also include antioxidant and antiglycation activities in vitro.On this basis,the hawthorn pectin was applied to the DEAE-52 column for separation and purification,and the eluted peaks were collected and concentrated,dialyzed and freeze-dried.The neutral sugar composition(WPS)and the acidic polysaccharide(SPS-3),which are the most abundant in the eluted fraction,were assayed for monosaccharide composition,infrared,and antioxidant and antiglycation activities.Finally,hawthorn pectin,hawthorn pectin hydrolysate,SPS-3 and SPS-3 hydrolysate were added as antiglycation agents to infant formula,compared the ability to inhibit advanced glycation end products(AGEs)formation.The results are as follows:1.Extraction and purification of hawthorn pectin: 1)Pectin was extracted by ultrasonic method(extraction power 200 W,250 W,300 W,350 W),enzymatic method,and hot water method.While decolorization was performed by using D3520.After discoloration,the color changes can be observed from bright red to milk white.The protein clearance rate of polyamide deproteinization was above 90%.The enzymatic extraction of pectin has the highest yield of 11.50%;followed by hot water extraction with a yield of 10.81%;ultrasonic extraction of hawthorn pectin has the lowest yield of only 8%.2)To explore the effects of different extraction methods on the physicochemical properties of hawthorn pectin.The results showed that the total sugar content(92.15%)and galacturonic acid content(74.11%)of the extracted hawthorn pectin were the highest when the ultrasonic power was 350 W.Theenzymatically extracted hawthorn pectin had the highest esterification degree(88.17%)and total phenolic content(0.10%),but the total sugar and galacturonic acid content were lowest.The pectin sulfate group content obtained by the hot water method(0.33%)was the highest.3)In the determination of antioxidant activity,the scavenging ability of DPPH free radicals,hydroxyl radicals and superoxide radicals is relatively strong when ultrasonic power is 350 W,while the scavenging ability of hot water method and ultrasonic method with extraction power 200 W on the three free radicals was relatively weak.In the antiglycation assay,the inhibition rate of AGEs was highest when ultrasonic power is 350 W,and the inhibition rate of hawthorn pectin extracted by enzymatic method was the lowest.2.Separation and purification of hawthorn pectin and determination of its properties.1)The hot water extraction of hawthorn pectin was separated and purified by ion exchange column DEAE-52 to obtain five components,including neutral sugar WPS and acid sugar SPS-1,SPS-2,SPS-3 and SPS-4.Among them,WPS and SPS-3have the highest content,so WPS and SPS-3 components are selected for monosaccharide composition,infrared and in vitro antioxidant and antiglycation activities.2)The carbohydrate content of WPS and SPS-3 were very close,but the uronic acid content of SPS-3 was much higher than that of WPS.The results of monosaccharide component indicated that the main monosaccharide of WPS was glucose(25.60%),galactose(36.50%),arabinose(14.60%)and rhamnose(10.50%),and the main monosaccharide of SPS-2 was galacturonic acid(72.30%),arabinose(17.30%)and rhamnose(3.60%).Combined with monosaccharide composition and FT-IR spectrum results,both WPS and SPS-3 were polysaccharides,and SPS-3 was pectin with high lipid.3)In the activity determination,the scavenging ability of SPS-3 on superoxide free radicals,hydroxyl free radicals,DPPH free radicals and the inhibitory ability on AGEs were all stronger than WPS.Therefore,SPS-3 was selected as an antiglycation agent to be added to infant formula milk powder for the determination of antiglycation activity in vitro.3.Determination of anti-glycation ability of hawthorn pectin and its enzymatic hydrolysate in infant formula milk powder: adding hawthorn pectin,hawthorn pectin hydrolysate,SPS-3 and SPS-3 enzymatic hydrolysate to powder.At the same time,no pectin and its hydrolyzed products were set as blank control,and aminoguanidine was added as a positive control.After 0,7,14,21 and 28 days of accelerated storage at60 ℃,the ability to resist glycation was compared.At the end of accelerated storage,the results showed that the fluorescence intensity of the blank control group increased by 154.18%,the fluorescence intensity of the hawthorn pectin group increased by72.09%,and the hawthorn pectin hydrolysate group increased by 86.68%.The SPS-3group increased by 45.06%,the SPS-3 hydrolysate group increased by 50.61%,and the aminoguanidine group increased by 44.23%.During the entire accelerated storage period,the order of increase in fluorescence intensity was blank control > hawthorn pectin hydrolysate > hawthorn pectin > SPS-3 hydrolysate > SPS-3 > aminoguanidine.It can be seen that SPS-3 has the strongest inhibitory effect on the formation of AGEs in infant formula,followed by SPS-3 hydrolysate,and the antiglycation activity of hawthorn pectin hydrolysate is the weakest.In conclusion,hawthorn pectin was used as the research object in this paper to decolorize and deproteinize the extracted hawthorn pectin,and then the purified hawthorn pectin was separated by column.The components with the highest content of WPS and SPS-3 were selected for the determination of monosaccharide composition,infrared spectrum and antioxidant and antiglycation activities.Since the antiglycation activity of SPS-3 in vitro was superior to that of WPS,SPS-3 was selected as the main antiglycation agent to be added into infant formula milk powder to explore its ability to inhibit AGEs.For comparison,hawthorn pectin,hawthorn pectin hydrolysates,SPS-3 and SPS-3 hydrolysates were added to the milk powder.The results showed that SPS-3 had the strongest antiglycation activity in the milk powder.This paper provides a theoretical basis for the development of natural food-borne antiglycation agents. |
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