A kinetic study on benzoic acid pungency and sensory attributes of benzoic acid

Aqueous solutions of benzoic acid (BA) were evaluated by two methods: (i) sensory profile: a descriptive test of sensory attributes combined with semiquantitative analysis; and (ii) pungency intensity measures as a function of time: a computerized recording using specific software. Kinetic parameters evaluated were maximal intensity (I(MAX)), total time of pungency (Ttot), rates of increase (V1) and decrease (V2), half-life (T1/2), area under curve (AUC) and time to maximal intensity (T(IMAX)). Results were analyzed by ANOVA, LSD test, iterative calculations and adjustment to equations according to mathematical models, regression analysis, principal component analysis (PCA) and clusters analysis. Pungency was the main sensory attribute of BA (3-36 mM) in the tongue and epiglottis. The seven kinetic parameters showed concentration-dependency (P < 0.001) and were described by different functions: (i) lineal: I(MAX) = 2.24 +/- 0.14C - 3.06 +/- 2.58, R2 = 0.98; T(IMAX) = 0.19 +/- 0.02C + 6.87 +/- 0.47, R2 = 0.92; V1 = 0.68 +/- 0.03C + 0.10 +/- 0.69, R2 = 0.99; AUC = 49.10 +/- 3.17C - 230.78 +/- 59.66, R2 = 0.98; (ii) potency: T1/2 = 6.62 +/- 0.61C(0.39+/-0.03), R2 = 0.97; V2 = 1.07 +/- 0.11C(0.53+/-0.04), R2 = 0.98; Ttot = 8.08 +/- 1.01C(0.43+/-0.04), R2 = 0.96. PCA revealed high correlation between (i) T(IMAX) and Ttot; (ii) T1/2 and V2; and (iii) I(MAX) and V1. Stimuli grouped across three main clusters: (i) 3 and 6 mM; (ii) 9, 12 and 18 mM; and (iii) 24 and 36 mM. Maximal pungency intensity best correlated with both concentration and persistence among kinetic parameters. Prototypical prickling of BA was observed at 12 and 18 mM.