Quantifying the impact of seed coat on the functional qualities of roasted pine nuts and its correlation with changes in multi-component interactions.

Abstract

This study investigated the effects of natural seed coats on quality formation of roasted pine nuts and underlying mechanisms. The intact seed coat imparted ideal crispness to the roasted pine nuts, improved paste properties (including cohesion, consistency index, viscoelastic modulus, and thixotropic recovery properties), and increased active compounds/antioxidant activity, reducing total lipid oxidation value by 45.03 %. 1-Pentanol and 1-octen-3-ol were key volatiles enriched in samples roasted with seed coats, favoring the balance of fresh woody aroma and roasted sweetness of pine nuts. Raman spectroscopy and LF-NMR/MRI revealed that seed coats promoted protein/polysaccharide insertion into lipid acyl chains, enhancing lipid binding and water retention capacity. Microstructural analysis showed that the shell-regulated roasting yielded smooth-surfaced nuts with compact cross-sections and uniform component distribution. Correlation network analysis inferred that roasting with in-situ coating controlled lipid mobility by promoting particle homogeneity and multi-component interactions, thereby creating conditions for quality improvement of roasted pine nuts.