Study On Antioxidant And Antifatigue Activity Of Red Raspberry Lyophilized Powder And Preparation Of Jam

Red raspberry,also known as raspberry(Rubus Idaeus L.),is the mature fruit of the woody plant of the genus Rubus in the Rosaceae family.Polyphenol compounds are the main chemical substances in red raspberry.In recent years,more and more studies have shown that red raspberry has the effect of lowering blood sugar,anti tumor,anti inflammatory and so on,which has a great health promotion effect.This study with raspberry producing as raw material,determination of the content of polyphenol compounds,inspects its oxidation resistance,anti fatigue activity,and to explore its correlation between polyphenol compounds and antioxidant activity,through the single factor experiment and orthogonal experiment the best formula of raspberry jam,and to study its storage stability,provide reference for raspberry application in food industry.The main results are as follows:1.Determination of polyphenols in freeze dried red raspberry powder:Ultraviolet absorption spectrophotometry(UV)was used to determine the contents of total polyphenols,total flavonoids and anthocyanins in freeze dried red raspberry powder.A High Performance Liquid Chromatography(HPLC)method was established to determine the contents of six polyphenols in red raspberry freeze-dried powder.The results showed that the contents of total polyphenols,total flavonoids and anthocyanins in the freeze dried red raspberry powder were 72.2 mg/g,10.84 mg/g and 0.18 mg/g,respectively.The established HPLC method has good selectivity,repeatability,stability,precision and accuracy.The contents of catechin,gallic acid,rutin,proanthocyanidin B₂,ellagic acid and quercetin in freeze dried red raspberry powder were 0.41,0.62,0.81,0.37,0.64,and 0.014?g/g.2.Study on antioxidant and anti fatigue activity of red raspberry freeze dried powder:The antioxidant activity of red raspberry freeze dried powder was evaluated by measuring hydroxyl radical,DPPH free radical and ABTS free radical scavenging rate and total reducing power.The results showed that the antioxidant activity of red raspberry freeze dried powder was obvious in vitro.When the concentration of red raspberry freeze dried powder reached 1 mg/mL,the scavenging rates of hydroxyl radical,DPPH radical and ABTS radical were 73.56%,73.64%and66.15%,respectively.The IC₅₀values were 0.316 mg/mL,0.269 mg/mL and 0.437 mg/mL,and has a very good ability to restorerespectively.According to the correlation analysis,the effect of rutin and gallic acid on the antioxidant activity of red raspberry freeze dried powder is obvious.The anti fatigue activity of red raspberry freeze dried powder was evaluated by measuring Blood Lactic Acid(BLA),Blood Urea Nitrogen(BUN)and Hepatic Glycogen(HG)in mice with weight bearing swimming test.The results showed that red raspberry lyophilized powder delayed the accumulation of lactic acid and urea nitrogen in blood and increased the content of liver glycogen in weight bearing swimming mice,suggesting that red raspberry lyophilized powder had anti fatigue effect.3.Preparation of red raspberry jam:Using red raspberry freeze dried powder as raw material,the effects of the addition amounts of water,carrageenan,xylitol and citric acid on the quality of red raspberry jam were investigated through single factor experiment and orthogonal experiment,and the optimal formula of red raspberry jam was determined.The results showed that when the supplemental levels of water,carrageenan,xylitol and citric acid were 36.4%,0.4%,36.4%and0.1%,respectively,the red raspberry jam had rich aroma,delicate taste,good tissue state and the highest score.The results of storage stability experiment showed that the storage time and temperature had great effects on the total polyphenols,total flavonoids,anthocyanins,moisture content,soluble solids,pH value and color of red raspberry jam.Compared with 25?,4?may be the best storage temperature for the jam.