The lipid oxidation process of Robusta green coffee beans was characterized during accelerated storage for 20 days at 40 °C, 50 °C, and 60 °C. The conventional oxidation indexes and fatty acid compositions were evaluated, and the shelf life of the green coffee beans was predicted using the Arrhenius model. The acid value, iodine value, peroxide value, total oxidation value, thiobarbituric acid reactive substances, and free fatty acid content increased throughout storage, while the moisture content, p-anisidine value, and unsaturated fatty acid content decreased, which suggests that lipid oxidation occurred during accelerated storage. The predicted shelf life of green coffee bean samples were 57.39 days, 44.44 days, and 23.12 days when stored at 40 °C, 50 °C, and 60 °C, respectively. This study provided scientific evidence of the impact of lipid oxidation on the loss of quality during the accelerated storage of green coffee beans.

The novel dyes of organoimido-substituted hexamolybdates for positive type dye-sensitized solar cells (p-type DSSCs) have been studied on the basis of time-dependent density functional theory (TDDFT) calculations. The electronic absorption spectra, light harvesting efficiency (LHE), charge separation efficiency (CSE), and holes injecting efficiency (HJE) of designed systems have been systematically investigated. The results reveal that the long π-conjugated bridge and auxochrome play crucial roles in red-shifting the absorption bands and reinforcing the intensity of the bands. Based on [(n-C4H9)4N]2[Mo6O18(N-1-C10H6-2-CH3)], the designed systems 6 and 4 are good candidates for p-type DSSC dyes due to the strong absorption in the visible region as well as high LHE, CSE, and HJE. The maximum absorption of the one-electron-reduced system obviously red-shifts to the visible region. Therefore, the highly efficient dyes of p-type DSSC can be prepared by reducing POM-based organic–inorganic hybrids which have both long π-conjugated bridge and auxochrome.

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