Impact of kernel hardness, protein, and total starch content on wheat starch digestibility

Wheat starch digestibility is crucial for its nutritional value, yet the impact of kernel hardness, protein content, and total starch content on this process remains unclear. To investigate this, we analysed 272 wheat varieties that were collected worldwide for hardness index (HI), grain protein content (GP), total starch content (TS), rapidly digestible starch content (RDS), slowly digestible starch content (SDS), and resistant starch content (RS). Correlation and regression analysis revealed that increased kernel hardness is associated with higher RDS and lower SDS, while GP negatively correlates with RS, and TS positively influences RS. Path analysis shows that TS has a stronger impact on starch digestibility, whereas the effect of GP is weaker. The results suggest that wheat varieties with softer kernels, higher TS, and lower GP content exhibit slower starch digestion, offering insights for breeding strategies to improve nutritional quality.