| Blueberry liqueur is a natural and healthy beverage product that is processed by special processes from blueberry concentrate,The sour-sweet and tasty blueberry juice and the elegant and delicate maotai-flavor liquor are allocated have a rich fruity,and the aftertaste is more abundant and unique.Blueberry liqueur is rich in procyanidins,which can resist oxidation and scavenge free radicals,fight cancer,regulate blood lipid and anti-aging.However,its quality stability is different from the general liqueurs,which is derived from the productive process without any additives,but the natural healthy products obtained through special processing.Its quality stability depends on the stability of the procyanidins in Maotai-flavor liqueur.Through the study of the stability of procyanidins in blueberry liqueurs,it provides references for the research and industrial development of blueberry liqueurs.At the same time,it will help stabilize product quality,extend shelf life,and improve production standards for enterprises.It will provide technical support and experience for the production and processing of such high-juice,high-nutrition,and zero-added pure natural liqueurs.In order to further explore the procyanidins stability of blueberry liqueur,in this paper,the extract of procyanidins in blueberry liqueur was studied to determine it extraction process,establishment it detection methods,study the stability and oxidation resistance.The main results are as follows:1)Preliminary established the extraction process of procyanidins:the extract was obtained by degreasing,extraction,elution,vacuum concentration,freezing drying process,etc.in the process of procyanidins extraction,by single factor test,it is concluded that the yield of procyanidins from the optimal conditions of single factor ethanol volume is 70%,solid-liquid ratio is 1:7,extraction temperature is 50 ? and time is 50 min.2)On the basis of single factor,the extraction process was optimized by response surface,the yield of procyanidins was used as evaluation index,Four factors were selected for ethanol volume,solid-liquid ratio,extraction time and temperature,the response surface analysis of the procyanidins yield in blueberry liqueur was designed by using the Box-Behnken center combination principle,the test results were analyzed with variance analysis and regression model,and get the regression equation: Y=4.686-0.19A+0.042B+0.29C+0.52D+0.015AB-0.13A-0.29AD+0.08BC+0.065BD+0.34CD-0.74A2-0.34B2-0.56C2-0.59D2.Response surface analysis predicted the optimum extraction conditions of procyanidins in blueberry liqueur:66.96% ethanol volume,soild-liquid ratio of 1:18(g/m L),extraction temperature 55.08 ?,the extraction time is 56.71 min,under the condition of procyanidins yield of 4.97 mg/g.The experimental results show that the model can predict the extraction conditions of the procyanidins yield in blueberry liqueur,and finally determine the technological conditions:67.0% ethanol volume and solid-liquid ratio of 1:7.2(g/m L),extraction temperature 55.1 ?,the extraction time is 56.7 min,under the condition of procyanidins yield of 4.82 mg/g.3)Three methods: HPLC,n-butanol hydrochloric acid and vanillin hydrochloric acid were used.Through the repeatability,stability,repeatability and sample recovery,the quantitative detection method of procyanidins in blueberry liqueur was evaluated.Results show that the HPLC,n-butanol hydrochloric acid and vanillin hydrochloric acid method have good repeatability,stability and reproducibility.Three methods of determination of procyanidins standard addition recovery rate of average achieves the requirement of the samples determination,by contrast,high performance liquid chromatography RSD value is the lowest,The times of vanillin hydrochloric acid method,n-butyl alcohol of hydrochloric acid method is higher.Therefore,HPLC is more suitable for the determination of procyanidins in blueberry liqueur by HPLC.4)The effects of different p H values,temperature,illumination,metal ions and additives on the stability of procyanidins extract were studied,the results showed that proanthocyanidin was stable in the acidic environment,the p H values increases gradually and the stability decreases;Proanthocyanidin was stable at low temperature and decreased with the increase of temperature;Light can destroy the structure of procyanidins,resulting in degradation of procyanidins,and reduced the stability of procyanidins;The stability of Mg2+,Na+,K+,Cu2+,Ca2+ and Fe3+ has a certain effect on their stability.The influence of Cu2+,Ca2+ and Fe3+ was obvious.Sodium phosphate,glucose,sodium chloride and citric acid were added into the procyanidins solution respectively,and the results showed that the stability of procyanidins could be improved by glucose and citric acid in a certain concentration range.In order to improve the stability of procyanidins in the process of procyanidins processing,storage and use,the procyanidins should be placed under the conditions of acidic,low temperature and light avoiding,contact with metal ions such as Cu2+,Ca2+,Fe3+ should be avoided,proper addition of a certain amount of food additives can improve the stability of procyanidins.5)During the study of the antioxidant activity of procyanidins in blueberry liqueurs,The procyanidins in blueberry liqueur has a significant effect on DPPH and superoxide anion free radical(O2·-),and the cleared effect is greater than VC.Therefore,this experiment further confirmed that the antioxidant properties of procyanidins are several dozens of times the antioxidant properties of VC. |
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