Microbiological, Proximate and Organoleptic Analyses of A Fermented Condiment Made from Seeds of Citrullus lanatus (Watermelon)

Abstract

Aim: This study was conducted to investigate the potential of the protein-rich oily seeds of Citrullus lanatus (watermelon) as raw material for fermented condiment production, and conduct the microbiological, proximate and organoleptic analyses of the condiment. Study Design: This is a laboratory-controlled experimental design. Place and Duration of Study: Dept. of Microbiology, Food and Industrial unit, Nasarawa State University, Keffi, Nigeria, between March and May 2017. Methodology: A local condiment (‘ogiri’) was made from dried seeds of Citrullus lanatus (watermelon) by Nigerian traditional method of condiment-making. Microbial enumerations of the fermented product and its raw (unfermented) sample were conducted using standard techniques. The proximate composition of the samples was conducted. Also, sensory evaluations of soup formulations made with the condiment from watermelon seed and a similar product from ‘egusi’ melon seed were carried out to determine their consumer acceptability. Results: The condiment obtained from traditional fermentation of Citrullus lanatus seeds was an oily brownish paste that has a characteristic pungent smell. The enumeration of the fermentative organisms showed that total aerobic growth ranged from 3.2x102 cfu/g at the starting time to 2.88 x108 cfu/g at the end of the fermentation period. There was no fungal growth at the beginning of the fermentation, till Day 1 that ranged from 8.0x103 cfu/g to 6.0x106 cfu/g on Day 5. The result of the proximate composition show that the moisture content of the dried fermented product was 3.5%, protein was 21.1%, fat was 36.9%, carbohydrate was 33.0% and ash was 5.5%. The result of sensory evaluation generally indicated that there was no significant difference (p≥0.05) in all the quality attributes of the soup samples analyzed. Conclusion: It can be concluded that Citrullus lanatus seeds can yield a highly nutritious, microbiologically and organoleptically acceptable fermented condiment.