Comparative Analysis of Mechanically Extracted Oils from Underutilized Seeds: Yield, Physicochemical Properties, and Antioxidant Potential for Industrial Applications

Abstract

The global demand for plant-based oils continues to rise, yet many underutilized 
seeds remain unexplored despite their nutritional and industrial potential. This 
study conducted a comparative evaluation of oils mechanically extracted from 
five underutilized seeds; black seed (Nigella sativa), flax seed (Linum 
usitatissimum), mustard seed (Brassica juncea), sweet melon seed (Cucumis 
melo), and castor seed (Ricinus communis). Using a standardized screw-press 
method and AOAC analytical protocols, the oils were assessed for yield, key 
physicochemical properties (iodine value and saponification value), and 
antioxidant potential (total phenolic contents and DPPH radical scavenging 
activity) to determine their industrial suitability. Castor seed yielded the highest 
oil contents (30.55%), while flaxseed oil exhibited the greatest unsaturation 
(iodine value: 153.21 g I₂/100 g). Sweet melon seed oil recorded the highest 
total phenolic contents (0.75 mg GAE/g), and all the oils demonstrated 
moderate but significant DPPH radical scavenging activity (50%). The 
saponification values (176.9–188.4 mg KOH/g) are within the acceptable range 
for soap and cosmetic formulations. The results highlight the unique 
compositional profiles of each oil: Black seed and mustard oils are valuable for 
nutraceutical and cosmeceutical applications due to their antioxidant capacity; 
and castor oil remains suitable for specialized industrial and pharmaceutical 
uses. The study provides a scientific basis for the valorization of underutilized 
seeds, supporting their integration into value-added products while promoting 
economic diversification and sustainable practices.