Increased diffusivity of lycopene in hot break vs. cold break purees may be due to bioconversion of associated phospholipids rather than differential destruction of fruit tissues or cell structures

Abstract

Lycopene bioaccessibility is enhanced by processing, as explained by the destructuration of plant tissues, making diffusion easier. However, in tomato, the relationship between grinding intensity and lycopene release from purees suffers from uncertainty. In particular, hot break puree exhibited twice as much diffusible lycopene as compared to cold break, while both were processed with the same grinding intensity. To explain the difference, we systematically studied the diffusivity of particles according to their size and integrity, and used microscopic and physical analyses to reveal structural differences. Neither particle size distribution, nor cell destruction, nor plastid transformation exhibited any correlation to the differences in diffusivity. However, Raman microspectroscopy combined with a chemometric analysis revealed significant changes in lycopene spectra and a putative linkage to phospholipid transformation. Phospholipid profiling of five pairs of contrasted purees revealed that, during the cold break, a transition from complex phospholipids to more simple phosphatidic acid molecules systematically occurred.