Enhancement of physicochemical, microbiological, and sensory properties of oil cake fortified with wheat bran, α-amylase microcapsules, and Roselle extract nano-emulsions during storage

Abstract

Cakes are prone to staling and spoilage, with wheat bran (WB) fortification often compromising texture and sensory quality. While α-amylase microcapsules (EM) and Roselle extract nano-emulsions (REN) offer benefits, their stability and effectiveness in cakes remain limited. This study aimed to assess the impact of EM and REN on various attributes of oil cake during storage. The total phenol content (TPC), antioxidant activity (AA), and active compounds of RE were first evaluated, followed by antimicrobial activity (AMA) against common pathogens, with significant results against Staphylococcus aureus. Oil cake formulations were tested after adding WB, EM, and REN, and observations were made after 28 days of storage at 25 ± 2 °C. Results showed that cakes with WB, EM, and REN had a 30% increase in moisture content (MC) (from 15 to 19.5 g/100 g), a 24% improvement in texture (force to compress increased from 2.5 N to 3.1 N), and a 40% reduction in microbial growth (from 1.2 × 10⁶ CFU/g to 7.2 × 10⁵ CFU/g). Shelf life increased by 35% (from 10 days to 13.5 days). These findings highlight the potential of EM and REN in enhancing the physicochemical (30% in MC, and 24% in texture), oxidative (a decrease of 128% in peroxide value), and microbiological (40%) properties of oil cakes during storage in plastic packaging.