| In recent years, though the output of plums grow rapidly, market is dominated by fresh fruits, which leads to a large number of fruits rotting. Thus, researching new plum products has very important practical significance, and it helps expand markets, increase revenues. Fraiar plum was used in this paper as the raw material in brewing fermented plum wine, pericarp anthocyanin stability and the color changing in different aging environment were studied. Results are as follows:1.The determination of maximum absorption wavelength and plum fruit anthocyanins stability The maximum absorption wavelength of anthocyanins in Fraiar plum pericarp is 515nm; pH has great influence on anthocyanins of plum fruit skin, and red color will be deepen with the decreasing of pH value; In short time and low temperature condition, the stability of anthocyanins in Fraiar plum skin is good; However,when greater than 40℃, anthocyanins solution will be significantly faded; Anthocyanins of plum fruits in the skin is sensitive to light, and should be preserved in darkness; Anthocyanins in plum fruit peel shows poor stability, when meet oxidant or reductant.2.Optimization of Fraiar plum wine fermentation process parameters The best Fraiar plum wine fermentation conditions:SO2 dosage of 80mg/L, fermentation temperature 21 ℃, fermentation time 9d. And it alcohol content is 13.4%, total sugar is 3.75g/L, total titratable acid is 4.5g/L, free sulfur dioxide is 54mg/L, the total sulfur dioxide is 78mg/L, volatile acid content is 0.34g/L, dry extract is 18.6g/L of plum fruit wine. All physical and chemical indexes meet the requirements of GB/T 15038-2006.3. The quality of Fraiar plum wine The Fraiar plum wine is clean and transparent, pale purplish red, with intense plum aroma, mellow taste, and long after-taste. The total number of bacteria (CFU/mL)≤47, coliforms (MPN/100mL)<3, did not detect pathogens. All those show that the plum wine quality is good.4. Identification of fraiar plum wine color The CIELab parameters of 13 samples were determined. The CIE parameters of Fraiar plum fruit wine not aged (No.0):L*=86.7, a*=12.8, b*=8.36. A* represents the red hue, positive, indicating the wine body is red; b* represents the yellow hue, positive, with yellow trend; Compared with the tone figure, the liquor body is purple. The color identification of other samples used the same analysis methods; Compared with the original wine, aging samples shows that red hue is weakened, yellow hue is strengthen. The best aging condition is at room temperature without lighting(No.8).5. Correlation between total anthocyanins and CIELab parameters Total anthocyanins amount of not aged sample (No.0) is 27mg/L. The total amount is less than 30mg/L, and it can be identified as peach red wine by color classification. Overall, total anthocyanins in various aging conditions is less than before; Total anthocyanins amount and a* has very significant positive correlations, and has significant negative correlations between with L*, Hab. |
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