Tahir , Mahmood (2011) Investigation Of Valuable Phytochemicals In Native Berries And Cherries Fruits. PhD thesis, University of Agriculture, Faisalabad.
In view of the ever-increasing interest and demand for safer antioxidants by the food industry and preventive medicine, the research on natural antioxidants has gained considerable momentum. Soft fruits such as strawberry, mulberry and cherry are emerging crops with high economic value, not only due to their desired taste but also for their known health-promoting properties.The subject fruits being a potential source of functional bioactives and natural antioxidants namely, phenolic acids and flavonoids with reported medicinal health functions have gained much attention.It is widely accepted that cultivar, genotype and maturation stages can affect the profile of antioxidants, phenolics and minerals in fruits.The present research project was mainly designed to evaluate the compositional changes in valuable nutrients and antioxidants of strawberry, mulberry and cherries fruits in relation to different maturity stages/ripening and extraction protocols.Proximate analysis reveals that tested fruits are a good source of protein, crude fiber and minerals which vary considerably with regard to fruit ripening. Antioxidant components of fresh, ambient and sun-dried fruits were extracted using two solvents in different concentration, methanol (100 %, 80 %) and ethanol (100 %, 80 %) and three extraction techniques- orbital shaker, magnetic stirring and ultra-sonication-assisted stirring. Overall, best possible extraction yields of antioxidant components were obtained with 80% methanol using ultra-sonication-assisted stirring from sun-dried fruits.The tested fruits also showed good amounts of total phenolics and flavonoids and DPPH radical scavenging activity.The composition of individual sugars, organic acids, flavonols and phenolic acids was studied using chromatographic techniques such as HPLC and GC-MS, etc. Fructose and glucose were established to be the major sugars in all tested fruits while citric and ascorbic acid predominant in strawberry and mulberry, while in cherry, tartaric acid being the major organic acid.The tested fruits mostly showed an increasing trend in the concentration of sugars and organic acids as fruit maturity progressed.HPLC analysis for flavonols and phenolic acid showed that Morus laevigata contained high levels of flavonols (myricetin, quercetin, kaempferol) at fully ripened stage followed by strawberry. Relatively higher amounts of phenolic acids namely p-hydroxy benzoic acid and p-coumaric acid were found in strawberry and cherry than those in other fruits, while mulberry contained p-coumaric, chlorogenic and vanillic acid in higher amounts. Overall, the present study explored the tested fruits from Pakistan to be a potential source of natural sugars, organic acids, minerals and natural antioxidants (phenolics), suggesting their utilization as nutraceutical and functional foods ingredients for promoting health of consumers.The results also advocate the significant effect of ripening stages on the nutritional and antioxidant properties of the tested fruits. Besides, aqueous organic solvent and sonication-assisted stirring proved to be the best possible extraction systems to recovering the maximum amounts of potent antioxidants from these fruits.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Nutraceutical, Investigation, Fruits, Phytochemicals, Protein, Native, Methanol, Antioxidant, Cherries, Chromatographic, Berries, Valuable|
|Subjects:||Physical Sciences (f) > Chemistry(f2)|
|Deposited By:||Mr. Javed Memon|
|Deposited On:||28 Feb 2013 10:40|
|Last Modified:||10 Jan 2015 17:22|
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