Effects Of Rosemary Extract On The Antioxidant And Eating Quality Of Salami

Salami prone to excessive oxidation in machining process,moderate fat oxidation,protein oxidation,hydrolysis reaction can produce the flavor substances such as aldehydes and alcohols,which is beneficial to the quality of the salami.However,excessive oxidation could have negative effects on its flavor,texture and color quality.The common method that is used to control the oxidative and rancidity of fermented sausage is to add antioxidants.Currently the most antioxidant used in industry is synthetic antioxidants which have better antioxidant effects,but its safety has been questioned.Thus in many countries,synthetic antioxidants has beenn banned to be used in meat products.People gradually turn their attention to the natural antioxidant.Rosemary natural antioxidant is made from rosemary extract which has stronger antioxidant ability and good safety without producing side effects.At present,the study of rosemary extract mainly focuses on the extraction methods of the chemical composition,function and mechanism of action The study about rosemary extract antioxidant properties in the salami and its effects on the eating quality of salami is rare.In this study,rosemary extract was added to the salami,and its influences on antioxidant capacity and eating quality of the salami was studied.The concrete research content and conclusions are as follows:1.The antioxidant activity of rosemary extract in vitroWith rosemary powder as material,using 70%ethanol as solvent extraction,the total polyphenol contents of rosemary extract were determined by Folin-Ciocalteu method.The scavenging effects of rosemary extract on DPPH free radicals,ultra oxygen anion free radicals(O2-·),the oxygen radical absorbance capacity(ORAC)and the reductive activity were investigated using the same concentration of sodium D-isoascorbate as control.The results showed that the total polyphenol content of rosemary extract was 19.8%.The DPPH free radical clearance rate gradually increased with the increase of rosemary extract concentration.When the concentration was greater than 80 ?g/mL,the scavenging rate of rosemary extract on DPPH was higher than that of sodium D-isoascorbate(P<0.05).In the concentration range of 5?g/mL to 80 ?g/mL,the ultra oxygen anion free radicals(O2-·)clearance ability of rosemary extract was higher than sodium D-isoascorbate under the same concentration(P<0.05).In the tested concentration range,the average ORAC value was 2920.3 ?mol Trolox/g which was significantly higher than that of sodium D-isoascorbate(1746.9 ?mol Trotox/g)(P<0.05).There was no significant difference in the reductive activity between rosemary extract and sodium D-isoascorbate when the concentration reached certain level.2.The influences of rosemary extract on lipid and protein oxidation in the salamiDifferent concentrations of rosemary extract were added to salami,and two experimental groups were set as the control group.One was added D-isoascorbate,and another group was without any the antioxidants.Different concentrations of rosemary extract were added to salami and the pH value,water activity value,(L*,a*,b*)value,TBARS value,and the total protein thiol content were measured during the processing of salami.The results showed that the pH value of the experimental-group with rosemary was lower than 5 in the limit time,that has reached the requirement for product safety.There was no significant differences in pH values between 0.02%and 0.03%of the rosemary extract treated group with the addition of 0.02%sodium ascorbate(P>0.05).The water activity of the five experimental groups showed a gradual downward trend during the whole fermentation period while the addition of rosemary had no significant effect on the change of water activity in the whole process of salami(P>0.05).The a*/b*values of the three adding rosemary treatment groups were significantly higher than that of adding the 0.02%sodium ascorbate group(P<0.05).The addition of rosemary extract could improve the color of salami.The addition of 0.03%rosemary extract could effectively inhibit the lipid oxidation during the processing of salami,and the effect was better than 0.02%sodium ascorbate(P<0.05).The addition of 0.02%and 0.03%rosemary extract could significantly inhibit the protein oxidation,and showed a certain dose effect relationship(P<0.05).The 0.03%of rosemary inhibited the oxidation of protein with the equivalent of 0.02%sodium ascorbate.3.The effects of rosemary extract on the eating quality of salamiDifferent concentrations of rosemary extract were added to salami to study the the influence of rosemary extract with different concentrations on the sensory quality of salami through the determination of final product structure,main content,composition and content of volatile flavor and taste substances(free amino acids,free fatty acid),and the sensory evaluation of the final product.Results indicated that compared with the control group,the addition of 0.02%and 0.03%of rosemary extract could significantly decrease the hardness,adhesiveness and chewiness(P<0.05).The rosemary extract was also helpful to improve the water content(P<0.05),but not to the content of protein and fat Among the 17 free amino acids,the most abundantfree amino acids in the experimental group were alanine(2.142-2.434g/100g),followed by glutamic acid(1.727-2.056g/100g).Except tyrosine,cystine and threonine,there were no significant differences between the experimental groups in the contents of the remaining 14 free amino acids(P>0.05).The addition of 0.03%rosemary extract increased the type and the content of unsaturated fatty acids in salami,which is helpful to improve the flavor and nutritional value of salami.A total of 179 volatile compounds were detected in the five experimental groups and volatile substances with a relative content of more than 1%included aldehydes,alcohols,hydrocarbons,ketones,acids and ethers.The types of hydrocarbon compounds in the three rosemary treatment groups were significantly higher than those in the control group.Adding rosemary extract was beneficial to inhibit excessive generation of hexanaL The relative content of 2-and 3-hydroxy methyl ketone in the treatment group with the addition of rosemary was higher than that of the two control groupsthat was good for the formation of the final flavor.In this experiment,the result of sensory evaluation showed that the addition of rosemary extract had no significant effects on the sensory score of salami.