Influence of Highland Barley Flour on Nutritional Quality, Dough Characteristics, and Volatile Aroma Compounds in Cakes

Effects of highland barley flour (HBF) with different proportions (10%, 30%, and 50%) in cakes were explored in this paper. Cakes enhanced with HBF had higher nutritional quality. In vitro simulated digestion experiments revealed that as the proportion of HBF increased, both the starch hydrolysis index (HI) and the estimated glycaemic index (eGI) of cakes decreased correspondingly. Thermomechanical analyses indicated significant increases (p < 0.05) in water absorption rates and stabilization times of the mixed dough with increasing proportions of HBF. Additionally, protein weakening and starch gelatinization properties were notably impacted. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) analyses revealed disruptions in the gluten network structure. Raman spectroscopy and measurements of disulfide bond content indicated that the stability and spatial structure of wheat gluten proteins were compromised by the inclusion of HBF. The distinctive aroma profile of cakes containing HBF is attributed to key volatile compounds such as acetoin, (Z)-4-heptenal, propanoic acid, 2-heptanol, 2-heptanone, and 1-hexanal. This study offers a theoretical basis and practical guidance for developing cakes enriched with HBF.