Study On Optimum Fermentation Conditions And Antioxidant Activity Of Raspberry Vinegar

Raspberry(Rubus corchorifolius L.f.),also known as raspberry,mountain boil,milk froth,seedling froth,April froth,thorn gourd,steamed bun spinach,sauerkraut,has the reputation of "golden fruit".Raspberries are rich in nutrients,containing main active substances such as anthocyanins,superoxide dismutase,polyphenols,and flavonoids,as well as rich vitamins and minerals.Medically,raspberries are believed to have astringent essence,improve eyesight,help yang,nourish the kidney,sober up alcohol and quench thirst,resolve phlegm and detoxify.Because of its good medicinal value and health care effect,raspberry is considered to be a new fruit resource with great development potential.Raspberry products such as raspberry fructose and raspberry juice drink are very popular among consumers.Raspberry vinegar is produced through alcohol fermentation with yeast and acetic acid fermentation with acetic acid bacteria.Raspberry vinegar retains the rich nutrients and unique flavor of raspberries while taking into account the multiple nutritional functions of vinegar.This experiment uses raspberry as the raw material,through single factor and orthogonal experiment to determine the most suitable acetic acid fermentation conditions for this experiment;the content of the physiologically active components of raspberry vinegar,and the free radical scavenging ability of raspberry vinegar Measurements include DPPH,·OH,·O2-,ABTS+,iron ion scavenging capacity and total antioxidant capacity.The research results are as follows1.The optimal fermentation conditions for the alcohol fermentation stage are:fermentation temperature is 18℃,fermentation substrate sugar content is 16%,Fermivin yeast is used,and the addition amount is 0.1%of the mass of fruit pulp.When the alcohol content of the raspberry wine made by fermentation under these conditions reaches 6%,it is pressed and filtered to terminate the fermentation.2.The optimum fermentation conditions for the acetic acid fermentation stage are:fermentation temperature 30℃,acetic acid strain is Acetobacter pasteurianus 20056,vinegar mother inoculation amount is 10%.3.Study on the physiological activity of raspberry vinegar:In terms of active substances,the content of polyphenols in raspberry vinegar brewed in this experiment was 163.2 mg/100 mL,the content of flavonoids was 24.3 mg/100 mL,and the content of anthocyanins was 4.94 mg/100 mL.The total acid content of raspberry vinegar is 6.57 g/100mL,the reducing sugar content is 3.25 mg/100mL,and the amino acid nitrogen content is 0.16 g/100mL4.The clearance rate of raspberry vinegar for DPPH is 84.45%;the clearance rate for ·OH is 60.96%;the clearance rate for ·O2-is 48.95%,the clearance rate for ABTS+is 31.07 mmoL/L,and the iron ion reduction ability It is 25.24 mmoL/L,and the total antioxidant capacity is 1.62 U/mL.