On surface composition and stability of β-carotene microcapsules comprising pea/whey protein complexes by synchrotron-FTIR microspectroscopy

[Display omitted] •β-carotene microcapsules were produced with pea/whey protein as wall materials.•Polysaccharide addition resulted in microcapsules with less porous structure.•Synchrotron-FTIR revealed protein and lipid distribution on capsule surface.•Cross-linking and polysaccharide addition increased aggregated β-sheet in protein.•Heteroprotein with maltodextrin effectively encapsulated and protected β-carotene. This study aims to elucidate the stability of spray dried β-carotene microcapsules by identifying their surface composition using synchrotron-Fourier transform infrared (FTIR) microspectroscopy. To investigate the impact of enzymatic cross-linking and polysaccharide addition on heteroprotein, three wall materials were prepared: pea/whey protein blends (Con), cross-linked pea/whey protein blends (TG), and cross-linked pea/whey protein blends-maltodextrin complex (TG-MD). The TG-MD exhibited the highest encapsulation efficiency (>90 %) after 8 weeks of storage followed by TG and Con. Chemical images obtained using synchrotron-FTIR microspectroscopy confirmed that the TG-MD displayed the least amount of surface oil, followed by TG and Con, due to increasing amphiphilic β-sheet structure of the proteins led by cross-linking and maltodextrin addition. Both enzymatic cross-linking and polysaccharide addition improved the stability of β-carotene microcapsules, demonstrating that pea/whey protein blends with maltodextrin can be utilised as a hybrid wall material for enhancing the encapsulation efficiency of lipophilic bioactive compounds in foods.