Technological benefits of using inulin and xylooligosaccharide in dulce de leche

Abstract The addition of prebiotic ingredients (inulin or xylooligosaccharide, XOS, 2.5 g/100 g) on ​​the quality parameters of Dulce de Leche (DL) was evaluated. Gross composition, hydroxymethylfurfural (HMF) values, rheological tests (texture profile analysis, TPA), color parameters, water mobility (TD-NMR), fatty acid profile, and crystal size (optical microscopy and predictive modelling) were performed. DL samples exhibited an appropriate gross composition and energy value. The addition of inulin improved the cohesiveness for full-fat milk samples while XOS led to a firmer, adhesive, and gummy texture, regardless of the fat content of the products. Regardless of the prebiotic ingredient, lower HMF values and more intense optical parameters were observed, without negative impact on the fatty acid profile. Regards TD-NMR, it was observed that inulin contributed to decrease the spin–lattice relaxation time (T1) when compared to XOS, resulting in a more homogeneous structure. The products with prebiotic components showed less development of lactose crystals compared to controls, and a delay in the increase of the crystal size during storage, observed by the predictive models. The addition of inulin or XOS to DL formulations proved to be an interesting alternative, inducing positive structural changes, and providing improved functionality, considering technological and functional purposes.