Yield and miraculin content of nine miracle fruit (Synsepalum Dulcificum) morphotypes

Abstract

Miracle fruit (Synsepalum dulcificum) is an understudied tropical fruit species with potential as a source of natural, non-caloric sweetener. Miracle fruit berries have been consumed in Africa for over 100 years. The fruit pulp contains a protein called miraculin, a natural, non-caloric sweetener, that changes the perception of sour foods and beverages to sweet. Demand for natural, non-caloric sweeteners like miraculin is increasing due to the growing number of people affected by chronic diseases associated with high sugar consumption. Miracle fruit could play a role in reducing sugar content in some food and beverage applications, but basic plant yield data and miraculin content in the fruit is generally lacking. To overcome these limitations, fruit yield and miraculin content were analyzed for individual plants from a commercial miracle fruit farm growing nine plant morphotypes. Miracle fruit plants in general followed synchronized flowering periods with six harvest peaks within a single year with the largest yields from May to July. Total average yield ranged from 0.06 to 3.44 kg/tree/year for individual plants. The highest yielding plant morphotype was ‘Imperial’ with 2.76 kg/tree/yr. Average fruit weight ranged from 1.22–1.54 g, and pulp thickness ranged from 0.21–0.31 cm. A simplified extraction and quantification method was used to quantify miraculin from fruits. Miraculin content ranged from 0.07 for a ‘Holly’ morphotype to 1.30 mg/g of juice for a ‘Flame’ morphotype as measured by HPLC using recombinant miraculin as a protein standard. Overall, this study identified variation in both yield and miraculin content across sixty-six mature miracle fruit plants. These results will be useful for selecting superior plant types and provide foundational information supporting a new industry growing the natural, non-caloric sweetener miraculin.