Production and evaluation of physicochemical and sensory quality of a liqueur combining orange-fleshed sweet potato and lemon balm

Abstract

Liqueur is a spirit drink resulting from a mixture of ethyl alcohol of agricultural origin and/or brandy, drinking water, sugar and possibly other foodstuffs, with a sweet taste and flavored by maceration of vegetable substances or by distillation of the same substances or by the addition of flavorings. The aim of this study was to assess the physicochemical and sensory quality of a combined orange-fleshed sweet potato and lemon balm liqueur. Four formulations were produced: (A) 30% water, 15% sweet potato and 2% lemon balm; (B) 35 % water, 10% sweet potato and 1.5 % lemon balm; (C) 45% water, 5% sweet potato and 1% lemon balm; and (D) 47% water, without sweet potato and lemon balm; all of which contained 45% alcohol (purchased from the local market and redistilled in the laboratory) and 8 % sugar, were produced and characterized in terms of pH by potentiometry, titratable acidity by titration, total soluble solids content (ºBrix) by refraction, alcoholic strength by alcoholmeter and sensory value using affective methods. The results showed pH ranging from 5.43 to 6.51, titratable acidity from 2.26 to 12.66%, total soluble solids around 17.76±0.15 to 26.20±0.1 ºBrix and alcohol content from 12.60 to 21.30 %v/v. Significant differences were found in pH, titratable acidity, total soluble solids content and alcoholic strength. Sensorially, the acceptability index of the liquor formulations produced indicated that the best formulation was B, with acceptability of 71.14%, and 25% of the tasters stated that they would buy it. The orange-fleshed sweet potato combined with lemon balm is an alternative for making liqueurs and could contribute to product diversification.