Red lentil tofu enriched with nivik ( Arum maculatum ) extract: Effects on functional and bioactive properties

Plant-based functional foods enriched with natural bioactive compounds have attracted increasing attention due to their potential health benefits. However, studies on the functional enhancement of non-soy tofu systems remain limited. In this study, the use of nivik ( Arum maculatum ) leaf extract as a functional ingredient in red lentil tofu was investigated. Tofu samples were prepared with different extract concentrations and evaluated in terms of phenolic and flavonoid contents, antioxidant activity (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) [ABTS], 2,2-diphenyl-1-picrylhydrazyl [DPPH], and FRAP), dietary fiber composition, and α-amylase inhibition activity. Total phenolic content increased progressively with increasing extract concentration, reaching 77.01 ± 0.92 mg GAE/100 g in tofu supplemented with 5.00% extract, compared to 19.90 ± 0.65 mg GAE/100 g in the control sample, with a similar trend observed for total flavonoid content. Antioxidant capacity also increased markedly with extract addition. Extract incorporation further enhanced dietary fiber content and α-amylase inhibitory activity (16.0%–35.8%), indicating a concentration-dependent functional improvement of the tofu matrix. These results indicate that nivik extract improves the bioactive composition and antioxidant capacity of lentil-based tofu. Overall, red lentil tofu enriched with nivik extract represents a promising plant-based product with enhanced bioactive properties.