Production and free radical scavenging activity of guyabano (Annona muricata L.) peel tea with varying levels of honey and calamansi (Citrus fortunella microcarpa B.) juice

The production of tea drinks typically uses tea leaves but now various sources, like the bark and peel of certain plants, are being used. Guyabano (Annona muricata L.) peel has a higher free radical scavenging activity (FRSA) than its pulp. This enables the use of guyabano peel as a medium for tea production. This study was conducted to formulate guyabano peel tea with varying levels (0, 5 and 10% v/v) of honey and (0, 2.5 and 5% v/v) of calamansi (Citrus fortunella microcarpa B.) juice. Physico-chemical properties of the product, such as total soluble solids concentration (TSS), pH and titratable acid (TA) were determined and sensory qualities (color, aroma, taste, flavor, general acceptability) were evaluated using a 9-point hedonic scale. Consumer preference testing and free radical scavenging activity were determined on the optimum formulation and on an existing product. The optimum formulation has the potential to compete with existing green tea products in the market. The addition of honey and calamansi juice increased the overall acceptability score to be≥6.8 (like slightly to like moderately) of guyabano peel tea. The TSS and pH of guyabano peel tea decreased at a high concentration of calamansi juice, while TSS and pH increased with added honey. The FRSA values of the control (0% honey and 0% calamansi juice), the highly acceptable product (10% honey and 5% calamansi juice) and the existing green tea product were 246.84, 342.91 and 333.96 μmol Trolox Equivalent 100 mL^‑1, respectively. The optimum formulation of guyabano peel tea, with 8.4% honey and 3.0% calamansi juice, had an FRSA of 324.64 μmol Trolox Equivalent 100 mL^‑1.