Screening of Citric Acid-degradation Yeast and Application in Blueberry Wine
|School||Anhui Agricultural University|
|Course||Of Food Science|
|Keywords||Screening Acid-degradation Blueberry Wine Application|
Organic acid in wine can protect wine color.Acid with appropriate quantity canmake wine taste downy, harmonize, however overmuch organic acid can make thetaste hard and sharp. Most fruits contain various organic acids, among which citricacid content is mayor, such as citric, orange, pineapple, blueberries, usually becauseof the influence of factors such as harvest time, the citric acid content is not alwaysthe same. Citric acid can promote the metabolism of human body heat, eliminatefatigue, promote digestion, but too much citric acid will destroy wine flavor.Therefore, in order to effectively degrade organic acid in wine, many scholars studieddifferent methods, mainly including chemical, physical, and biologicalacid-degradation.Blueberries are rich in sugar, organic acid and the anthocyanins, and juice yield ishigh, suitable for processing wine products. Blueberry wine belongs to none-foodtype low-degree wine, drinking for long-term reasonably can adjust humanphysiology balance, which is good for health. The research has focused on blueberrywine’s brewing technique, abundant organic acids make blueberry wine acidity high.For the purpose of citric acid-degradation wine, this paper through the biologicalacid-degradation method studied mainly in the following related research:(1)Establish organic acid’s test methods in blueberry wine;(2) Screening citricacid-degradation yeast, study the effect of application in Blueberry wine and theinfluence on the sensory quality of wine;(3) Identification the yeast by genomesequence analysis of26S rDNA D1/D2and study toxicology safety of the yeast,growth characteristics and optimize the culture medium formula.1. Establish organic acid’s test methods in blueberry wine; Using mobile phase:NH4H2PO4(4g/100mL), pH2.0; flow rate:1.0mL/min; wavelength:210nm;temperature:25℃; chromatographic column: Waters symmetry C-18(4.6×250mm,5μL). Through this method, blueberry wine was found nine mainorganic acid, oxalic acid, tartaric acid, malic acid, citric acid, different extracting acid,lactic acid, acetic acid, citric acid, succinic acid which was effectively separated andquantified, the recovery was99.52%and RSD was0.019%on average.2.Screening citric acid-degradation yeast;study the effect of application inblueberry wine and the influence on the sensory quality of wine; The result showedthe citric acid degraded from10.2322g/L to4.6617g/L in the medium of citric acid asthe only carbon source when inoculated the yeast for11days. Furthermore, the yeast was innoculated into blueberry wine, citric acid degraded from1.1440g/L to0.5971g/L for9days,and acid-degradation effect was significant, total sugar, alcoholdegrees and anthocyanins almost had no change.3.Identification the yeast by genome sequence analysis of26S rDNA D1/D2andstudy toxicology safety of the yeast, growth characteristics and optimize the culturemedium formula. The sequence’s length of product by PCR was561bp. Afterhomology analysis,the target strain can be identified as Sporidiobolus spp.By acute toxic class (ATC) method (oral),the result proved maximum tolerateddose (MTD) exceeded10000mg/(kg BW), the yeast was actual non-toxic level.The yeast can use glucose, sucrose, maltose, lactose, galactose, raffinose exceptmelibiose in fermentation; the order using carbon source:glucose> sucrose> lactose,not use soluble starch, xylose and sorbose; the order using nitrogen source:ammonium sulfate> peptone> urea;the growth curve showed its growth was dividedinto four phases,: lag phase, exponential phase, stationary phase, decreasing phase.