Evaluation of African Star Apple (Chrysophyllum albidum) Seed Oil as a Potential Feedstock for Industrial Application

Aims: Evaluate possible application of African Star Apple seed oil as industrial raw material geared towards possible conversion of waste to wealth with no negative impact as it borders on food scarcity. Also unveiling the possibility of a sustainable environment via the eradication of waste from the environment, thereby creating a clean environment.

Place and Duration of Study: Fresh ripped fruits of African Star Apple were bought from some local market sellers at Agbarha-Otor market which is located in Ughelli North Local Government Area of Delta State, Nigeria on longitude 6° 2' 54" E /5° 30' 40" N, between November, 2019 and March, 2020.

Experimental Details: Soxhlet extraction with n-hexane as solvent was used for the oil extraction of 100 g per batch of extraction. Pretreatment procedure of oil was done prior to transesterification. Homogenous base-catalyzed transesterification reaction was used in this study under controlled experimental conditions such as temperature, reaction time, methanol to oil molar ratio and catalyst type and concentration were examined under varied ranges to ascertain optimum experimental conditions for the reaction. Extracted seeds oil were analysed for its physicochemical properties using standard methods via: specific gravity, acid value, refractive index, saponification value, iodine value and free fatty acid using standard methods.

Results: The results showed an oil yield of 14.9%, an indication that the seed reflects a poor source of abundant oil. Results obtained for the physiochemical properties, revealed that; specific gravity, refractive index, saponification value, acid value, free fatty acid and iodine value showed values of 0.896 kg/m3, 1.549, 231.32 mgKOH/g, 3.23 mgKOH/g, 2.07% and 47.63 mg/100 g respectively. Also, results for Methanol: Oil ratio showed that maximum yield was obtained at 6:1 molar ratio. Maximum conversion efficiency for molar concentration was achieved at 0.75% for both catalysts. While a reaction time of 125 min projected better yield.

Conclusion: The seed of African star fruit are discarded as waste, therefore its use as a source of oil for industrial feedstock and other domestic application, poses no challenge with regards to food security. Its non-drying potential based on its low iodine value, makes it suitable lubricating oil for industrial application. Similarly, potential application of the oil as feedstock for the production of biodiesel is justified on the basis of its low acid value. Conclusively, the seeds may not have sufficient oil volume potential to be used as edible (domestic) and industrial oil. Consequently upon its low yield, application for biofuel production in commercial scale becomes unrealistic.