Characterization of Functional Properties and Organic Acids in Vangueria infausta Burch. (Wild Medlar/Nzvirumombe/Umviyo) Fruit(s) Found in Zimbabwe

Abstract

Edible indigenous wild fruits are popular in the communities they are found. In recent years, these fruits have been purveyed in urban markets and contribute to household income. However, the nutritional and other health benefits of some of the fruits have not been studied. The objectives of the current study were to detect and identify the bioactive compounds that give Vangueria infausta fruits their unique flavor characteristics and proposed health benefits. The study detected and quantified the phytochemical compounds present and profiled the volatile organic compounds and organic acids in the fruit. The phytochemicals detected were phenols, tannins, flavonoids, anthraquinones, alkaloids, coumarins, terpenoids, glycosides, anthocyanins, and quinones, which were extracted in both methanolic and aqueous solutions. Antioxidant activity was determined using the DPPH scavenging assay, and volatile compounds were determined using gas chromatography. Organic acids were determined using HPLC. It was observed that the V. infausta fruits contained phenols, tannins, flavonoids, coumarins, alkaloids, anthocyanins, and terpenoids. The concentration of total phenolic compounds, total flavonoids, and total tannins in methanolic extracts was significantly (p ≤ 0.05) higher than those in the aqueous extracts. The total phenolic content (TPC) of V. infausta fruit pulp was found to be in the range 128–170 mg GAE 100 g−1 dry weight basis, which corresponded to the low antioxidant activity of less than 20% that was recorded. Formic acid (68.25 mg/kg) and ascorbic acid (297.3 mg/kg) were the two organic acids detected in the fruit pulp. Various volatile compounds were also detected in the fruit pulp including 5-hydroxymethylfurfurals and fatty acids such as ethyl octadecanoic acid, methyl stearate, methyl and ethyl hexadecanoic acid, and methyl-2-furoate. Methyl stearate, hydroxymethyl furfurals, and methy-2-furoate were novel compounds in the current study. It was therefore concluded that the V. infausta fruits contained bioactive compounds that are important for its flavor and have both pharmacological and food processing applications. Further studies are needed to investigate options for value addition, propagation, and conservation of the fruit V. infausta.