Effects of Thermal Processing on the Nutritional Antinutrient and In Vitro Antioxidant Profile of Monodora myristica (Gaertn.) Dunal Seeds

摘要

Proximate, minerals, and anti-nutrient content of raw Monodora myristica seed and Monodora myristica seeds boiled and roasted for 10, 20, and 30 min, respectively were assessed. In addition, the effects of boiling and roasting for 10, 20, and 30 min on the antioxidant properties of Monodora myristica seed extract were evaluated. Results showed that moisture, ash, fat, and crude protein were significantly reduced by boiling and roasting. Acid and neutral detergent fibres were significantly increased by roasting and boiling, with boiling causing a more significant increase than roasting. Processing resulted in significant decrease in magnesium, potassium, phosphorus, zinc, copper, manganese, and iron while calcium levels were unchanged. Total phenolics levels of raw seeds [(21.94 mg/100 g gallic acid equivalent (GAE)] showed a remarkable decrease (18.64 mg/100 g GAE) when the boiling time was increased to 30 min. Free fraction phenolics increased with thermal processing whereas bound phenolics decreased. Boiling was more effective in reducing anti-nutrients than roasting. Extracts of Monodora myristica seeds possess significant 1,1-diphenyl-2-picrylhydrazyl and 2,2’-azinobis( 3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging properties in a concentration-dependent manner, and this was significantly reduced after thermal processing. Monodora myristica seed extracts could be pharmaceutically exploited for antioxidant properties, and roasting may be preferred to retain the nutrient composition and antioxidant properties of Monodora myristica seeds.