Synergistic antioxidant activity of selected medicinal plants in Brunei Darussalam and its application in developing fortified pasta.

Abstract

Developing functional foods by utilizing plants can often lead to compromised sensory properties. Thus this study investigates the combination of plants to produce synergistic effects and to incorporate these plant powders into a pasta formulation without affecting its sensory acceptance. Six common Brunei medicinal plants were evaluated for their in vitro antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 ), ferric reducing antioxidant power (FRAP) assay and 2,2'-azino-bis(3-ethylbenziazoline-6-sulfonic acid) (ABTS) radical scavenging assay. Aqueous extracts of Amaranthus tricolor, Breynia androgyna, Manihot esculenta, Polygonum minus, Apium graveolens and Coriandrum sativum were prepared. Breynia androgyna had the highest FRAP value of 74.3 ± 5.33 mg g-1 ascorbic acid equivalents (AAE), with DPPH IC50 antioxidant activity of 70.3 ± 3.14 μg mL-1 and ABTS scavenging activity of 44.0 ± 2.80 mg g-1 AAE. This correlates well with the total flavonoid, flavonol and phenolic content (50.5 mg g-1 gallic acid equivalents (GAE), 50.6 mg g-1 GAE and 24.3 mg g-1 GAE, respectively). Plant species powders were combined in pairs and evaluated for their synergistic antioxidant properties. With potential synergistic plant mixtures, fortification of these mixtures into functional food can be developed to improve its overall antioxidant capacity. Based on the synergistic IC50 results of these mixtures, three fortified pastas were formulated by incorporating selected plant powder combinations of Amaranthus tricolor + P. minus, Apium graveolens + P. minus, and P. minus + B. androgyna into wheat pasta at 1:100 (w/w). Fortification of pasta with the plant powder blends resulted a significant increase in DPPH antioxidant activity, while successfully maintaining indistinguishable features from the control pasta, including minimal cooking loss, agreeable measure of cohesiveness, springiness and chewiness, with good overall sensory acceptability. © 2022 Society of Chemical Industry.