Optimization of the Sensory Acceptability of an Ameliorated Traditional Cameroonian Herbal Tea (“mendím me zoñ”), Using Simplex Lattice Design
摘要
The ingredients of a traditional herbal tea recipe called “mendím me zoñ” (mature Solanum torvum fruits, Cymbopogon flexuosus leaves, and Plectranthus glandulosus leaves) were optimized using response surface methodology (RSM). This herbal tea is known for its hypotensive, lipid-lowering, and hypoglycemic properties, making it a promising option for the development of a functional beverage. The aim of the study was to formulate the herbal tea from the powders of these ingredients and to optimize its sensory properties, including color, odor, taste, flavor, and general acceptability, using a constrained three-component mixing plan comprising 12 formulations. In these, the powdered eggplant ranged from 50 to 100 g, Cymbopogon flexuosus powder (0–50 g), and Plectranthus glandulosus powder (0–50 g). 4.0 g of each formulation contained in an infusible bag was infused and subjected to hedonic analysis. Results showed that all three of the ingredients used significantly (p < 0.05) affected the sensory properties of the formulated herbal tea. Regression models of sensory attributes against formulation components and the desirability function revealed that the optimal mixture was 59 g of eggplant powder, 40 g of lemongrass powder, and 1 g of P. glandulosus powder for 100 g of herbal tea. This optimal formulation had a desirability of 0.81, and their observed sensory scores were 7.67 (appearance), 8.30 (odor), 8.28 (taste), 7.38 (aftertaste), 5.85 (flavor), and 8.03 (overall acceptability). The R2 values (0.81–0.96) and t-test p-values (0.01–0.03) between experimental and observed sensory scores showed a good fit of the generated models in predicting the sensory parameters of this herbal tea as a function of the amount of each ingredient in the mixture.