Effects of carbon dots in combination with rosemary-inspired carnosic acid on oxidative stability of deep frying oils

Antioxidative carbon dots (CDs) were prepared and first characterized in terms of their morphology, size and microstructure. The feasibility of CDs to enhance oxidative stability of a blend soybean and palm frying oil was then evaluated; the efficacy of CDs was evaluated in comparison with those of rosemary-inspired carnosic acid (CA), combined CA/CDs and tert-butylhydroquinone (TBHQ). CDs appeared as spherical nanoparticles with the size smaller in general than 1 nm. Their characteristic features could be attributed to their oxygen functional groups and highly defected graphitic structure. CDs exhibited superior properties for scavenging DPPH, hydroxyl and superoxide anion radicals. Both CA and CDs showed significant inhibitory effect against oxidative rancidity of the oil. Interestingly, 0.05% CA/CDs displayed similar inhibitory effect as 0.02% TBHQ in terms of p-anisidine value, total polar compounds content, fatty acids composition, conjugated diene and triene contents as well as color and viscosity of the oil.

Automated summary

The antioxidative properties of carbon dots (CDs) were characterized, showing superior scavenging abilities for different radicals. CDs, along with carnosic acid (CA) and CA/CDs, exhibited significant inhibitory effects against oxidative rancidity in comparison to tert-butylhydroquinone (TBHQ).