<![CDATA[Background. Strawberry (Fragaria × ananassa) is a rich dietary source of anthocyanins—red-purple flavonoid pigments with antioxidant activity—but its high perishability means it is most often preserved as jam, a product that conventionally carries a heavy sucrose load. Replacing sucrose with the non-nutritive glycoside sweetener stevia (Stevia rebaudiana) could lower the sugar burden, yet its impact on both consumer acceptance and pigment retention in strawberry jam has not been characterised together in a single product. Objective. To quantify the effect of graded sugar-to-stevia substitution on (i) the sensory acceptability and (ii) the total anthocyanin content of strawberry jam. Methods. Five formulations were prepared: a sucrose control (F0) and four formulations substituting 1, 3, 5, and 7 g stevia per 100 g strawberry (F1–F4). Anthocyanin content was measured by the pH-differential method (UV-Vis spectrophotometry; cyanidin-3-glucoside equivalents) under a one-factor completely randomised design with three replicates per formulation. Acceptability of colour, aroma, taste, and texture was rated by 30 untrained panellists on a five-point hedonic scale in a within-subject design. Anthocyanin data were analysed by one-way ANOVA with Tukey HSD post-hoc tests after verifying normality (Shapiro-Wilk) and variance homogeneity (Levene); hedonic data were analysed by the Kruskal-Wallis test. Results. Anthocyanin content differed markedly across formulations (one-way ANOVA F(4,10) = 86.25, p < 0.001, η² = 0.97). It was highest in the sucrose control F0 (66.93 ± 2.22 mg L⁻¹) and lowest in F3 (45.57 ± 0.89 mg L⁻¹), a 31.9% reduction, but rose again in F4 (52.71 ± 1.84 mg L⁻¹) despite its higher stevia dose, revealing a non-monotonic dose–response. Hedonic ratings differed significantly for every attribute (Kruskal-Wallis: taste H = 23.08, p < 0.001; colour H = 17.80, p = 0.001; texture H = 16.87, p = 0.002; aroma H = 12.68, p = 0.013), with acceptance declining as the stevia dose increased and F0 preferred throughout. Conclusion. Sugar-to-stevia substitution exerted a significant, formulation-dependent rather than strictly dose-dependent effect on both anthocyanin retention and sensory acceptability of strawberry jam. Moderate substitution offers the most workable compromise between sugar reduction and product quality, but a genuine “low-sugar” label claim would require direct sugar-composition analysis, which was outside the present scope.]]>
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