Comparative Effects of Drying Methods on Phytochemical Contents and Anti-Microbial Activities of Watermelon (Citrullus Lanatus) Seed and Rind

Abstract

Plants and fruits are consumed for their nutritional and medicinal purposes but the effectiveness of such may be dependent on their pre-treatment method prior use. This study investigated the effect of drying methods on the phytochemical and anti-microbial properties of watermelon (Citrullus lanatus) seed and rind. The seed and rind were dried using air drying, oven drying and sun-drying methods. The methanolic extract of each sample was screened for phytochemical content (saponin, tannin, alkaloid, steroid, flavonoid, cardiac-glycoside, terpenoid, phenol and phytate). The extracts were also sreened for anti-microbial activities using six bacteria: Staphylococcus Aureus, Bacillus Cerus, Pseudomonas Aureginuss, Pseudomonas Florescence, Eshericial Coli, Salmonella Typhi and two fungi: Penicillium Oxaticum and Penicillium Chrysogenium. The result showed that all the phytochemicals were present in oven dried seed and rind. Cardiac-glycoside and flavonoid were absent in the air-dried samples while phenol and phytate were absent in the sun-dried samples. The antimicrobial screening showed the oven-dried seed and rind were more effective against all the bacteria and fungi than the sun-dried and air-dried samples. However, the sun-dried samples had more anti-bacterial and anti-fungi properties that the air-dried ones. Although oven drying is less considered as a drying method for fruits, it is recommended that watermelon (Citrullus lanatus) seed and fruit be oven-dried in order to effectively preserve its medicinal values.Keywords: Drying Method, Phytochemicals, Antimicrobials, Watermelon Seed, Watermelon Rind