Extraction of natural antioxidants from orange juice factory waste
2001
Chougui, N.
Recently, much interest has been expressed in finding new and safe antioxidants from natural sources because of their beneficial effect on health and their ability to preserve food. Such compounds are found in edible and non-edible plants, microorganisms and waste, the latter constituting a major problem in the food industry in that an efficient means of disposal has not yet been found. The present work seeks to identify the existing opportunities for the application and use of waste in the food industry, and more exactly in the orange juice processing industry. The orange peel as solid waste after pressurisation for juice making and essential oil extraction constitutes a rich source of a large number of phenolics (especially flavonoids) that are of economic value and have a potential market. To isolate these compounds, several extraction procedures involving solvents and other systems were perfomed and the main extracts obtained were evaluated for their antioxidant activities using: The RANCIMAT Test, the DPPH Free Scavenging Method, a Chemiluminascence Assay. Reverse-phase H.P.L.C. was used to characterize and quantify the content of the extracts, and the total phenolic content was determined colorimetrically using the Folin Ciocalteu Method. The choice of procedure was based on the antioxidant activity and the chromatographic profiles of the obtained extracts. The results showed thet the aqueous calcium hydroxide extraction system, at pH7, resulted in high amounts of hesperidin, while after further extraction, other compounds such as hydrocinnamic acid (cinnamic, ferulic and p-coumaric acids) were prevalent and showed high activity as was seen for KOH-W 1 per cent (SP), ETH.ACE, Ca(OH)2 (Ph3.5,LP,P1), Eth.Ace and KOH-M 1 per cent (LP), Eth.Ace.
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