Impact of β-glucan addition on long-term starch retrogradation and digestion depends on starch fine molecular structures

β-Glucan could regulate starch retrogradation and digestion; however, its combined role with starch fine molecular structures remains unknown. Therefore, nine starches were selected, and their retrogradation and digestion properties were investigated after storage for 7 days with and without β-glucan. Notably, three groups of starches were identified based on the impact of β-glucan on retrogradation: inhibition (potato starch), minimal effect (buckwheat, lentil and wheat starch), and promotion (cassava, mung bean, sweet potato, corn and pea starch). It was proposed that only amylopectin chains with enough length can interact with β-glucan, inhibiting retrogradation. Nevertheless, β-glucan did not affect melting temperatures of retrograded starch. The addition of β-glucan reduced the digestion extent of all starches to varying degrees, possibly due to the increased V-type crystallinity and formation of thicker hydrogel matrix. These results improve the understanding of β-glucan-starch interactions, aiding the development of starchy foods with slow digestion and controlled retrogradation property. • Impact of β-glucan on retrogradation depends on starch fine molecular structure. • Long amylopectin chains interact with β-glucan to inhibit retrogradation. • β-Glucan did not affect the melting temperatures of retrograded starch. • β-Glucan reduces starch digestibility to varying extents.