A modified mid-level data fusion approach for evaluating different storage conditions on rice germ shelf life

This study explores the possibility of extending shelf life of rice germ (a by-product of rice milling process) by reducing water activity in combination with modified atmosphere packaging, without any heat treatment. Dried samples at different water activities (0.55, 0.45 and 0.36) were packed in air, nitrogen or under vacuum, and stored at 27°C for 322 days (7 sampling points). To the aim, a non-targeted approach was applied by means of an FT-NIR spectrometer in reflectance with a rotating sample holder and a portable e-nose, equipped with 10 non-specific MOS sensors. A 2D correlation map is developed combining e-nose data with NIR spectra to understand relationships between the two blocks. On the same data, a modified mid-level data fusion approach is applied to combine the information most correlated with time. To follow samples evolution during storage and identify different clusters according to the storage conditions, a PCA is applied on fused data. In terms of correlation, the sensors could be divided in two groups, negatively inter-correlated: sensors ascribable to aromatic compounds and correlated with the NIR band around 4000 cm-1; broad-range response sensors, linked with the NIR band around 7550 cm-1. Data fusion highlights the importance of water activity on rice germ storage, while no interesting differences were ascribable to modified atmosphere packaging systems.