Regulatory effects of Platycodon grandiflorus polysaccharides on dough quality and gluten protein structure in low-gluten wheat flour system

This study aimed to investigate the regulatory effects of PGP on dough processing characteristics and gluten protein structure in low-gluten flour system and to evaluate its potential in improving the quality of short biscuits. Results showed that PGP led to significantly increased water absorption by 1.90% and prolonged dough stability from 5.07 min to 6.48 min. The incorporation of PGP also resulted in reduced swelling and setback values of starch. DSC analysis showed that thermal transition temperature and enthalpy change (ΔH) of dough reached the maximum values of 127.1 °C and 796.8 J/g at 1.0% PGP, respectively. Structural analyses revealed that the addition of 0-1.0% PGP induced a conformational transition of gluten proteins from β-sheets to α-helices (from 17.89% to 19.91%) and random coils, acco mpanied by a 25.8% reduction in free sulfhydryl groups and a 56.3% enhancement in disulfide bond formation. Moreover, PGP of 1-2.0% led to significantly enhanced crispness of short biscuits, as puncture force decreased from 2.57 N to 1.86 N. Those results illustrated that PGP affected the processing performance and textural properties of low-gluten flour products through hydrogen-bonding and steric-hindrance effects, providing a formulation basis for utilizing PGP as a natural texture modulator in short biscuits.