The Use of D-Optimal Mixture Design in Optimizing Formulation of a Nutraceutical Hard Candy

The aim of this study was to optimize the formulation of hard candy with antiviral herbal extracts and flowered with Citrus limon peel essential oils. To substitute water fraction, the D-optimal mixture design was used. The optimized mixture fractions of the best hard candy formulation contain Curcuma longa extract (10%), Artemisia herba-alba Asso extract (3.33%), Glycyrrhiza glabra extract (1.66%), and Zingiber officinale extract (1.66%) and flowered by 20 μL/100 gram of Citrus limon essential oils. The effect of the addition had been investigated on the sensory, physicochemical, and phytochemical of the hard candy according to the optimal formulation. The main component of Citrus limon essential oil is limonene (52.47%), which has a pleasant lemon fragrance. The mixture of herbal extract added increased the total phenols, the flavonoid, and the ash content of the formulated hard candy (10.90 ± 0.50 mg GAE/g, 0.054 ± 0.02 mg CE/g, and 0.018 ± 0.009, respectively). The measurement of the DPPH free radical activity reveals a good antioxidant activity (26.4%). Furthermore, the sensory analysis has shown a good appreciation. Thus, formulated hard candy is a sensorially and therapeutically interesting product.