Novel ready-to-eat rice containing seaweed and shellfish with potential application as space food: overall food quality and antioxidant efficacy

Although ready-to-eat (RTE) foods are gaining popularity owing to their convenience, enhancing their nutritional value remains challenging. In this study, RTE-packaged rice intended for space food applications, fortified with green laver ( Enteromorpha prolifera ) and oyster ( Crassostrea gigas ), was developed and its nutritional composition and antioxidant activity were evaluated. Four RTE rice formulations were prepared as follows: rice (RPR), green laver-added (RPR-GL), oyster-added (RPR-O), and green laver and oyster-added (RPR-GLO). The proximate composition, mineral content, and antioxidant activity were analyzed to determine the functional impact of ingredient incorporation. Adding green laver and oysters significantly altered the proximate composition of the samples ( p < 0.05). Protein and ash contents increased notably in RPR-GLO, with protein increasing from 2.84% in RPR to 4.39% and ash content increasing from 0.04 to 0.69%. Oyster inclusion contributed to higher moisture and potassium contents, while green laver elevated ash and mineral levels but showed low iodine concentrations. RPR-GLO exhibited the highest radical scavenging activity in both DPPH (23.24%) and ABTS (28.21%) assays, representing approximately 3.5-fold and 4.2-fold increases, respectively, compared to the control sample (RPR), suggesting a synergistic effect between the two ingredients. Therefore, incorporating green laver and oysters into RTE-packaged rice enhanced its nutritional quality and antioxidant activity.