Alpha-Amylase-Modified Cassava Starch in the Presence of Calcium Lactate as a Sour Starch Substitute for Gluten-Free Breadmaking

Sour cassava starch is traditionally produced through spontaneous fermentation and solar drying, processes that induce molecular changes responsible for its high baking expansion but are difficult to standardize. Therefore, this study evaluated a sustainable enzymatic strategy to mimic the functional properties of traditional sour cassava starch through the synergistic action of α-amylase (6 U g−1) and calcium lactate (CL) (0, 3, 6, and 9 mg/g starch). Structural, rheological, functional, and nutritional properties were evaluated. The results showed that α-amylase (6 U g−1) was consistent with preferential modification of the less ordered regions, resulting in a redistribution of short-range molecular organization. The treatment containing 6 U g−1 α-amylase and 6 mg/g CL showed lower apparent amylose content, lower retrogradation tendency, higher gelatinization torque, and greater bread specific volume, while maintaining an estimated glycaemic index of 50.9. These findings demonstrate that this enzymatic modification represents a standardized alternative for producing high-quality gluten-free breads.