Quality of Miracle Berry Wine as Influenced by pH and Inoculum Levels

Abstract

Synsepalum dulificum (also known as miracle berry) fruit is rich in nutrients, flavour and antioxidant compounds. However, the fruit is underutilized in the sub region and susceptible to post harvest losses. In this study, miracle berry wine was produced and the effects of varying pH and inocula levels during fermentation (at room temperature for 7 days) on the wine parameters (soluble solids, pH, titratable acidity, acid taste index, total phenols and antioxidant activity) were investigated. During fermentation, changes in ˚brix and pH were also monitored. Total soluble solids varied between 4.8-20°Brix while total phenols and antioxidant activity (% DPPH inhibition) ranged 300-580 mg GAE/L and 52-86 %, respectively. There was a decrease in ˚Brix, pH, phenolic content and antioxidant activity for all samples fermented at varying pH after fermentation. There was, however, an increase in titratable acidity (7-14 g/L tartaric acid) and acid taste index after fermentation. Wine samples produced at pH of 3.8, 4.6 and 5.8 using 1% inoculum produced 13%, 10% and 10% (v/v) alcohol, respectively. With respect to varying inocula, there was a decrease in ˚Brix, pH, phenolic content and antioxidant activity for wine samples produced at pH of 4.6 and inocula of 1% and 2%, respectively, but increased in titratable acidity and acid taste index after fermentation. At the end of the fermentation process, wine sample with pH 4.6 and inocula of 1% and 2% had alcohol content of 10% and 12% (v/v), respectively. The study revealed that it is possible to produce red wine from miracle berry rich in antioxidant with possible health imparting benefits. Again, varying the pH and inoculum levels can affect the quality of the wine produced.