Multi-Scale Structural and in Vitro Digestion Properties of Amino Acids-Tiger Nut Starch Complexes and Applications in Noodles

Abstract

Protein and its hydrolysates play crucial roles as nutritional components in daily diets and additives in food processing, their effect on starch digestion attracted extensive attention. In this study, tiger nut starch (TNS) mixed with multiple type of amino acids were subjected to annealing (ANN) treatment. Through the analysis of morphological characterizations, physicochemical properties, molecular structure on the mixtures, and assessment of enzyme inhibition effects of these amino acids, the mechanism of diverse in vitro digestion properties of the resulting mixtures were examined. Our findings revealed that the addition of Phenylalanine (Phe), Lysine (Lys), and Histidine (His) significantly reduced rapidly digestible starch (RDS) content while increasing levels of slowly digestible starch (SDS) and resistant starch (RS) content. Phe, Lys, and His were found to influence digestion properties through molecular interactions, as indicated by analyses of relative crystallinity (RC) and short-range order. Notably, Lys and His exhibited notable amylase inhibition effects thereby further enhanced enzyme resistance: His on α-amylase (11.98%) and Lys on α-glucosidase (89.33%), respectively. Finally, wheat noodles prepared with TNS-Lys and TNS-His showed favorable processing properties and digestion resistant, highlighting their promising applications in low glycemic index foods.

Keywords: Amino acids, Cyperus esculentus, Digestion properties, Tiger nut starch.