Effect of Indian brown seaweed Sargassum wightii as a functional ingredient on the phytochemical content and antioxidant activity of coffee beverage.

Seaweed is a novel food source that is packed with bioactive compounds but is rarely used in its raw/cooked form. An efficient nutrient delivery medium is required to make the potential health benefits of seaweeds accessible to the general population while maintaining its palatability. In this study, coffee infused with different seaweed concentrations (1%, 3%, 5%) were prepared and their physico-chemical, phenolics, flavonoids, antioxidants, rheology, thermal and spectral characteristics were observed. Increase in seaweed concentration resulted in increased acidity and decreased total soluble solids of the beverage with no distinct color change. Rheological measurements showed flow behavior index in the range of 1.09-1.34 indicating dilatant tendency of the seaweed-coffee infusions which gradually decreased towards a Newtonian nature with increase in seaweed concentration. Higher detection of flavonoids and ferric reducing antioxidant power was possible with increase in seaweed concentration from 1 to 5%. However, no significant changes in total phenols and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity was observed. Sensory evaluation of the coffee drinks was done using fuzzy logic which showed highest sensory acceptability for the infusion with 1% seaweed concentration. Thermograms showed changes in flavor profile on increasing seaweed concentration which was later confirmed using Fourier transform-infrared spectroscopy. Results of the study highlight that coffee can be successfully used to mask the off-flavor of seaweed while disseminating its health benefits to the general population through an effective and extensively utilized food medium. © Association of Food Scientists & Technologists (India) 2019.