Study On Inspection And Accumulation Under Storage Conditions Of Lipofuscin-Like Pigments In Walnut (Carya Cathayensis Sarg.)

Lipofuscin-like pigments is a compound formed by the complexation of protein with malonaldehyde derived by the peroxidation of poly-unsaturated lipids. And it is implicated in cellular damage due to lipid peroxidation and ageing. Walnut(Carya cathayensis Sarg.) has sufficient antioxidant substances and protect enzymes which can retard the oxidation of fat. But the high moisture and unsaturated fatty acid content of walnut is also the reason of fat oxidation during storage. In this paper, the inspection of Lipofuscin-like pigments and the effect of storage conditions on it’s accumulation was studied; the relation between Lipofuscin-like pigments and lipid oxidation, membrane lipid peroxidation, browning reaction were discussed. The results were as follows:(1) The Lipofuscin-like pigments for the compound extracted from walnut were carried out directly on the original chloroform-methanol-warter mixture. The extracts from walnut showed an excitation maximum at360nm and an emission peak around430nm which is the expected spectrum for Lipofuscin-like pigments.(2) Lipofuscin-like pigments accumulated gradually with storage. The relative contents of lipofuscin-like pigments (express by fluorescence intensity) were closely correlated with rise in the temperature. As well, the accumulation of Lipofuscin-like pigments increase in the Oxygenated condition, rendering the tissue more susceptible to oxidative damage. Lipofuscin-like pigments content of walnut in light rises initially and then declines during senescence. It indicated that exposure to light caused the photooxidation of Lipofuscin-like pigments. The statistical analysis showed that temperature had a far greater impact on accumulation of Lipofuscin-like pigments than the ambient gas throughout the storage. The influence of temperature on Lipofuscin-like pigments was greater than the light at earlier storage, but the light condition became more important factors at later storage.Storage in low temperature, oxygen-free or dark could maintain the Polyphenols Content; The peroxide value and anisidine value of walnut increased generally during storage, suggesting that generation of lipid peroxidation. Statistical analysis showed a positive correlation with the correlation coefficient of0.98existed between content of lipofuscin-like pigments and the total Peroxide Value of walnut during storage. The observations support the contention that accumulation of Lipofuscin-like pigments in senescing membranes is attributable to lipid peroxidation. The rising of the formation rate of O2·-and the content of MDA indicated the degree of cell membrane lipid peroxidation enhanced during storage; The results also showed a positive correlation with the correlation coefficient of0.92and0.93separately existed between content of lipofuscin-like pigments and the MDA and O2·-production rate of walnut during storage, this suggested that cell membrane lipid peroxidation of walnut during storage should be considered in regard to the accumulation of Lipofuscin-like pigments. In addition, polyphenols Content declined while browning degree rised during senescence. The results showed a positive correlation with the correlation coefficient of-0.95and0.88separately existed between content of lipofuscin-like pigments and the Polyphenols Content and browning degree of walnut during storage. It demonstrated that browning reactions provides some contributions to the development of lipofuscin-like pigments. Moreover, interaction of peroxidised lipids has been shown to result in a rather Lipofuscin-like pigments, suggesting that generation of Lipofuscin-like pigments follows by lipid oxidation.