Clean-Label Starch Modifications: Dry Heat Treatment in Combination with Ion Exchange

Potato starch offers the unique potential of mineral enrichment through the presence of phosphorylated amylopectin chains. This property was utilised in a straightforward dual modification of native potato starch by combining mineral enrichment with dry heat treatments (DHT). DHT itself (110-130 °C, 3-6% moisture, 2 h) affords potato starches with lower viscosity and gelatinisation temperatures and higher contents of digestible starch. Prior ion exchange with Na⁺, K⁺, Mg²⁺, and Ca²⁺ enhanced the versatility of dry heat treatments. This study demonstrates the fine-tuning of functional properties (rheology) of these novel, dual-modified starches. Of special interest are magnesium and calcium due to their nutritional value and their valency, allowing ionic cross-linking. The present study contributes to the understanding of starch-ion interactions in DHT, clearly highlighting the role of specific ion effects, as per the Hofmeister series (K⁺ > Na⁺ and Ca²⁺ > Mg²⁺), in addition to the reversible ionic cross-linking effect of divalent cations. This knowledge is of use for potential substitution of chemically modified starches in food products, serving relevant trends and needs of today's food industry for clean-label starches.