Brewing Techniques And Flavor Substances Of Huanghua Pear Vinegar

Huanghua pear is one of the most important fruit trees cultivatedvarieties in Jianning, Fujian known as thin peel, crisp flesh, rich juiceand good taste. It belongs to Chinese pear as climacteric fruit. It’shard to storage without proper technology of fresh keeping and/ordistribution in time. In addition with the high temperature during itsharvest time, huge economic losses are caused. So it is necessary to findways out to make use of the excessive pear fruits before its corruption.This passage studied how to prepare Huanghua pear into vinegar in orderto resolve this problem. The main results are as follows：(1) With the juice and pomace of Huanghua pear, preponderant yeastswere isolated named as FJN1and FJN2. Adaptability of the two yeasts werestudied. Comparing the productive capability of two isolated yeast, FJN1and FJN2, besides two bought kinds, As2.300and As2.069, FJN2had a bettergas production and yeast ability. It has a lower alcohol conversion butbetter fermentation flavor, supposed to be aroma-producing yeast. As2.069was chosen as alcohol fermentation strain.(2) With As2.069as alcohol fermentation strain, the optimum rangeof initial sugar content, fermentation temperature and inoculation amountwere determined by single factor experiment. Orthogonal experimentindicated that the optimal initial sugar content was16%, fermentationtemperature26℃, inoculation amount10%, and finally got alcohol contentto be9.5%.(3) Comparing the fermentation capability of two different kinds ofacetic acid bacteria, As1.41was the best for acetic fermentation. Theoptimum range of initial alcoholic strength, fermentation temperature andinoculation amount were determined by single factor experiment.Orthogonal experiment indicated that the optimal initial alcoholicstrength was5.5%, fermentation temperature33℃, inoculation amount10%, and finally got total acid to be5.86g/100ml.(4) Aroma in Huanghua pear vinegar extracted by solvent extractionincluding volatile compounds and involatile compounds was analyzed byGC/MSD.40kinds of essential volatile components were detected covering16esters,9alcohols,4ketones,3acids,1hydrocarbons and2aldehydes.16kinds of essential involatile components were determined including4acids,5hydrocarbons,1alcohol. Comparative analysis revealed thatalcohols, esters, hydrocarbons and acids were the major componentsaffecting the flavor of Huanghua pear vinegar.