Co‐extract of green tea and black rice: incremental effect of antioxidant and anti‐inflammatory properties and their freeze‐dried double emulsion encapsulated powder

Abstract

SummaryThe study explored the combination effect between of green tea extract (GTE) and black rice extract (BRE) and the encapsulation process of the co‐extract. A 2:1 (w/w) ratio of GTE to BRE in citric aqueous solution at pH 6 showed the highest antioxidant activity (IC50 = 0.306 mg mL−1) with the strongest incremental effect (combination index = 0.547). It exhibited potent anti‐inflammatory effects, with sirtuin 1 enzyme‐stimulating activity (28.593 of fluorescent intensity) and NF‐κB protein suppression in RAW 264.7 macrophages (57.76% at 100 μg mL−1). Freeze‐dried double emulsion encapsulated powder (CEP) with the highest encapsulation efficiency (73.38%) and total polyphenol content (218.28 mg GAE g−1) was prepared using a lecithin to O phase ratio of 2:25 (w/w) and a chitosan‐carboxymethyl cellulose to W1/O emulsion phase ratio of 1:1 (w/w). Our findings suggest utilising CEP as a compound in functional food by contributing to improved health and well‐being.