Study On Fermentation Kinetics And The Fermentation Process Optimization Of Pomegranate Wine

The fruit of Pomegranate （Punica granatum L） is rich in nutrition, with health-care function and multipe altilizmy vaLue. Pomegranate wine contains many kinds of organic acids, amino acids, vitamins, flavonoids and minerals. It has special effects on preventing oxidation and cancer, lowing blood pressure, reducing glyceride in blood and inhibiting bacterium. The pigment of Pomegranate pericarp is an excellent natural color additive.The research includes: analysis of pomegranate’s basic components, fermentation kinetic models, dynamic changes of sugar content, alcohol during fermentation process, studied on Pomegranate wine’s fermentation, clarification, sensory evaluation, color stability, the optimum extraction and stability of Pomegranate pericarp pigment.The results are as follows:1. AnaLysis of pomegranate’s basic components. The results: water（pulp）80.04%, total acid（tartaric acid）3.29%, acid（pH）4.01, soluble solids13%, reducing sugar（as gLucose）125.22g/L, total sugar（as glucose）139.53g/L, tannin2.32%, flavonoids（seed）11.41mg/L, flavonoids（pericarp）61.87mg/L. Pomegranate fruit is nutrient-rich, including high soluble solids, flavonoids（pericarp） and sugar content these materials are good the growth and reproduction of yeast.2. Study of pomegranate wine’s fermentation kinetics. The results: yeast growth was consistent with S curve, R²=0.99867, better correlation, the model could describe the number of pomegranate wine yeast during the fermentation process. In the fermentation process, the sugar content was converted to alcohol, so that the sugar content showed a declining trend of dynamic change, and alcohol showed a growing trend of dynamic change.3. The best fermentation conditions were as follows: yeast inoculation quantity6%, levels of sulfur dioxide70mg/L, fermentation temperature26℃, static fermentation4～5d. The results are: wine alcoholicity10.3%vol, flavonoids content65.85mg/L. the liquor was precious stone red, nutritious and restorative, with pure taste, cLear transparent.4. Pomegranate wine’s sensory evaluation. The results: the highest and lowest score were orthogonal5and orthogonal8. The score of sensory evaluation was84.9.5. The three kinds of the pomegranate wines were produced with materials with seed, without seed and with1/3peel under the best fermentation conditions. The results: the highest alcohol content in wine was10.2%, which was produced by pomegranate juice with seed. The highest flavonoids content was716.4mg/L, which was produced by pomegranate juice with1/3peel and seed.6. Clarification of Pomegranate wine. The best clarification conditions were as follows: gelatin0.10g/L, chitosan0.8g/L, soap soil1.0g/L, diatomite0.8g/L. The clatify agent had certain effect to pomegranate wine components. The results: along with the increase of the content of the chitosan, alcohol, pH value and acidity of pomegranate wine almost had no change, but the flavonoids content and chroma decreased obviously. Then the chitosan had strong adsorption to flavonoid compounds.7. Study on stability pomegranate wine. Pomegranate wine’s suitable preservation conditions: low temperature acidic environment avoiding contacting with light, Fe3+and Al³⁺. K⁺, VC, benzene potassium and glucose were favorable to color. Citric acid could prevent bacterial pollution, and keeping the pomegranate wine quality.8. The best extracting conditions of granatum pigment were confirmed the ratio between liquid and material60（60:1）, power60W, temperature60℃, time7min. At such conditions, the color of was yellow, absorbance and chromatic aberration （L*、 a*、 b*） were perfect.9. Study on the stability of granatum pigment. The suitable preservation conditions: low temperature acidic environment avoiding contacting with light. Oxidant and reductant affected the extracted pigment liquid. Along with the increase of oxidant, the absorbance was increasing. On the contrary, along with the increase of reductant, the absorbance was decreasing. The pigment had strong antioxidant capability.