English abstract
Locally grown date palm fruit varieties such as Fardh, Khasab and Khalas at tamar and rutab stages were analyzed for bioactive compounds. Date Fruit (DF) extract was investigated for its antioxidant activities using several assay methods and for its protective effect against 3-nitropropionic acid (3-NP) induced neurotoxicity in pheochromocytoma (PC12) cells. The extraction of the polyphenols was conducted by changing solvents, temperature and pH. The stability of the polyphenols was also investigated. In addition the textural properties of DF (9 batches) were investigated using sensory, instrumental texture and physico-chemical properties to derive a correlation between these properties.
Among the three DF varieties Fardh variety had showed the highest phenolic and flavonoid contents and exhibited maximum antioxidant capacity. Further its extract was found to offer significant protection to 3-NP induced neurotoxicity significantly in PC12 cells by means of increasing the cell viability, improving the antioxidant status and by reducing the free radical generation. However, the exact mechanism of action is unknown and further extensive studies are warranted.
In the extraction studies the highest recovery of polyphenols was obtained by using a combination of low pk (=2) and high temperature (60°C) using methanol: water (4:1) mixture. Textural studies including Cluster analysis (CA) and principal component analysis (PCA) classified the 9 batches of DFs into 3 groups (hard-chewy, soft-medium-chewy and soft-non-adhesive) on the basis of their sensory and physico-chemical properties. Similarly, the results of instrumental TPA (Texture profile analyser) and physico-chemical properties classified them into 3 groups (hard-resilient, soft-springy and firm-adhesive). Significant correlation was obtained between sensory and instrumental textural attributes and with physico-chemical properties.
