Decoupling texture from nutritional composition in sugar and fat reduced pound cake: A physico-chemical approach to...

Reducing sugars and fats in cakes often compromises sensory properties, limiting consumer acceptance. This study proposes that the textural changes from 30% fat replacement (using dietary fibres) can be balanced by adjusting the water-sugar mixture properties through a concurrent 30% sugar replacement. Specifically, key physico-chemical parameters were investigated to design cake reformulation: (i) the volumetric density of hydrogen bonds, Φ_w,eff, affecting protein denaturation and starch gelatinization; (ii) the molar volume density of effective hydroxyl groups in the sugar molecules, N_OH,s/v_s, influencing starch pasting properties; (iii) the Flory-Huggins water interaction parameter, χ_eff, describing the hygroscopic properties of sugar mixtures; and (iv) the volume fraction of flour, Φ_flour. These parameters were independently varied and tested against phase transitions, dough rheology (temperature sweeps) and cake properties. Results indicated that all physico-chemical parameters (Φ_w,eff, N_OH,s/v_s, χ_eff, and Φ_flour) effectively described key physical properties associated with phase transitions and batter rheology during heating, as well as final cake properties. Biopolymer phase transitions and the viscoelastic behavior of batters were primarily governed by Φ_w,eff, while cake properties depended on all physico-chemical parameters combined. Sensory tests with naïve consumers confirmed that properly modulating these parameters yielded cakes with sensory attributes comparable to the reference. Notably, cakes with enhanced sweetness, softness, and moistness were achieved despite the 30% sugar and fat reduction, positively influencing liking. Overall, this study highlights a formulation strategy that decouples texture from nutritional composition, enabling improved sensory properties while lowering calorie density.