Cold plasma processing has emerged a promising green technology with great potential to improve the quality and microbial safety of various minimally processed foods and materials. However, studies on non-thermal plasma-induced chemical interactions between major food ingredients that might change chemical structure and biological properties are very sparse. Thus, the objective of this study was to evaluate the influence of a dielectric barrier discharge (DBD) treatment on principal trans-resveratrol (TR) in several food stuffs by spectroscopic (HPLC, NMR, MS) and biological analyses. TR was dissolved in methanol and directly exposed to atmospheric non-thermal plasma field at 250 W for different durations (10, 20, 40, and 60 min), 40% relative humidity, and 25 °C. TR treated with plasma for 40 min showed greatly enhanced inhibitory activities for α-glucosidase and α-amylase than parent TR. Newly generated unusual compounds (1, 2) and known compounds (3–6) from plasma treated TR for 40 min were characterized using chromatographic and spectroscopic methods. The predominant reaction of TR induced by cold plasma followed by typical dimerization of products included methylene bridge formation and cyclization of TR. Among predominantly generated products, new compounds 1 and 2 showed more potent α-glucosidase and α-amylase inhibition capacities than parent TR. These results might be used to modify structures and enhance biological property of TR during food processing using DBD plasma treatment. Display omitted •Dimerization of trans-resveratrol was accelerated in methanol solution induced by plasma.•The structures of newly generated compounds from trans-resveratrol were elucidated by extensive spectroscopic interpretation.•Newly generated trans-resveratrol dimers can contribute to the enhancement of anti-diabetic properties.•Quantitative HPLC analysis of newly generated unique trans-resveratrol dimers was conducted.