Study On Optimization Of Processing Technology For Wildstrawberry Wine And Its Antioxidant Activities

The resources of wild strawberry distributed in China are rich and wide, the fruits are pure nature, non-pollution with high nutritional value and strong healthy function. However,the processing and utilization of fruits are lower,there are lack of highly processed products.Development of wild strawberry wine is beneficial to the consumption of fruit, and can extend the industrial chain, increase industrial value. On the basis of fruit wine production technology, this research combined the material properties of wild strawberry, focused on its fermentation conditions and optimization of brewing process parameters, and evaluated its antioxidant activities.The aim of the paper was to provide theoretical basis for relevant enterprises to develope wild strawberry wine. The primary results showed as below,1. The main nutritional compositions of wild strawberry fruit were determined systematacially.Including the total sugar, soluble solids, moisture content, the type and content of amino acids, organic acids, minerals, fruit aroma, etc.The results showed that the total sugar was 54 g/L,soluble solids 7.1%,moisture content 86.2%.There were 14 kinds of amino acids detected in the wild strawberry fruit, containing 6 kinds of essential amino acids, leucine0.05%, lysine0.04%, valine0.04%, histidine 0.04%, phenylalanine 0.03% and threonine 0.03%. The elements of K, Ca, Na, Mg, P and trace elements Fe, Se, Mn, Cu, Zn were analyzed, respectively, the level of these mineral substances were 1383.00mg/kg,724.20mg/kg,17.79mg/kg,305.10 mg/kg,18.00mg/kg,0.45mg/kg,0.0192mg/kg,1.68 mg/kg,0.43mg/kg,and Zn was not detected.The citric acid 1.34% was mainly organic acids in wild strawberry.From the point of relative content, esters were the most aroma substances, followed by alcohol, ketones, volatile acid, aldehyde and phenol.2. The enzymolysis process parameters of wild strawberry fruit was selected.The best combination was pectinase 0.5 g/kg, temperature 40℃, time 150 min, and the juice yield was 82.0%.3. The fermentation parameters of wild strawberry wine was optimized. Vintage Red was choosed as Saccharomyces cerevisiae,and yeast addition amount 0.2 g/L, fermentation temperature 22℃, initial sugar 22%, SO2 40 mg/L. In this condition, the sensory score of wine was 89.2, the wine was clear and transparent with nice red color and harmonious aroma.4. The changes of phenolics content and antioxidant activity in the fermentation process of wild strawberry wine were ensured.At the main fermentation stage(0 to 14 days), total phenol and flavonoids gradually increased, anthocyanins content rised and later decreased.secondary fermentation stage(15-28 d), the content of total phenol, flavonoids and anthocyanins were maintain stability.The change of antioxidant activity in the fermentation process was as follows, at the main fermentation stage, the free radical clearance of DPPH and ABTS radical,and reducing power all showed a trend of increase, their ability were also maintain stability in the secondary stage. Compared with the ordinary type of red wine, the antioxidant activity of wild strawberry wine was well.5.The correlations between different phenolics, phenolics and antioxidant activity in wild strawberry wine were analyzed. There were significant correlations between the total phenol and flavonoids, the clearance rate of DPPH free radical,reducing power,but the total phenol and the clearance rate of ABTS radical was irrelevant.The correlations between the flavonoids and the clearance rate of DPPH free radical, the clearance rate of ABTS radical, reducing power were also significant.As well as the clearance rate of DPPH and the clearance rate of ABTS radical, the clearance rate of DPPH and reducing power, the clearance rate of ABTS radical and reducing power.In conclusion, the wild strawberry is a kind of resource which has rich nutrition and unique flavor, and can be used for processing.Based on the raw material of wild strawberry,its wine has a favourable organoleptic quality with unique fragrance of the fruit and nice antioxidant activity.The product has high added value and can also cater to the demand of modern consumer for food safety, it will has an expansively prospect for market application.