Research at UAF - Extraction of Natural Antioxidants from Agro-Industrial Wastes for Food Applications
Principal Investigator: Dr. Masood Sadiq Butt
Cell #: 03006622685
Fax #: 041-9201105
Co-Principal Investigator: Dr. Faqir Muhammad Anjum
Telephone #: 041-9201105
Duration: 24 Months
Cost: 38,39,892/-
Funding Agency: Higher Education Commission

Progress Reports

Abstract: Agro-industrial wastes i.e. potato, apple, banana and citrus peels and carrot pomace were analyzed for their phenolic contents with special reference to DPPH (1, 1-diphenyl-2-picrylhydrazyl), b-carotene and TPC (total polyphenols content). After extraction, the phenolic extracts were heated at 50 and 100οC for 60 and 120 min. The residual antioxidant activity was determined using TBA method. In order to ensure pH stability, the extracts were pre-incubated at various pH levels (3, 5, 7, 9 and 11), prior to storage. The storage session lasted for 90 days involving the antioxidant determination over a period of 30 days interval. Citrus peel and carrot pomace showed higher antioxidant potential i.e. 74.99 and 66.62%, respectively to scavenge the free radicals. Among various solvents, methanol showed a higher extraction rate followed by ethanol and hexane. Antioxidant capacity of citrus peel and carrot pomace extracts were found higher during storage. Moreover, 60 days storage study of oils of corn, cotton and sunflower was also conducted in which citrus peel extract in methanol was scored higher than carrot pomace. Sensoric judgement of cakes and cookies prepared from both extracts showed better acceptability and keeping quality of citrus peel extract.

Problem Statement: In the proposed project, peels and pomace of selected fruits and vegetables are being utilized for production of natural antioxidant to replace the synthetic ones and to promote the concept of value added food products.


  • Preparation of antioxidant extracts for efficient utilization of agro-industrial wastes
  • Exploitation of extracted antioxidant by determining their extraction yield, phenolic contents, antioxidant activity and radical scavenging properties
  • Evaluate the stability of extracts prepared from different sources
  • Utilization of extracts with the highest activity, economic justification and phenolic content in edible oils and different baked products to prevent auto-oxidation

Methodology: In this study, locally available agro-industrial by-products like citrus, apple, banana and potato peels along with carrot pomace were used for extraction of phenolics using hexane, methanol and ethanol to check their comparative efficiency. Extracts were evaluated for their antioxidant capacity by using DPPH (1, 1-diphenyl-2-picrylhydrazyl), b-carotene, TPC (total polyphenols content), pH, temperature and storage stability. Storage study was also conducted for corn, cotton and sunflower oil after using the selected extracts as source of natural antioxidants and comparison was made by BHA (0.02%) and blank, on the basis of oil analysis, includes; peroxide value (POV), free fatty acids (FFA) and thiobarbituric acid (TBA) value. Sensory evaluation for cookies and cakes made from selected extracts was carried out to judge the consumer acceptance. 
Results and Discussions:  The data obtained was scrutinized statistically and results of extracts analysis revealed that citrus peel and carrot pomace had high activity in DPPH, b-carotene, TPC, pH, temperature and better storage stability. Citrus peel extract exhibited DPPH inhibition ranged from 40.44 to 50.40%. Highest DPPH activity in carrot pomace 73.61% was observed in methanolic solvent, whilst lowest 56.27% in hexane. However, methanol and ethanol were selected for further assessment because of their high extraction rates. Among all phenolic extracts, high antioxidant activity was observed for carrot pomace and citrus peels. Likewise, maximum polyphenols were recorded in citrus peel extract 13.20±2.32mg/g followed by 11.74±1.82mg/g in apple, potato peels contained minimum polyphenols i.e. 3.64±0.63mg/g. During the storage of oil, it was inferred that citrus peel extract gave better stability among all extracts. Peroxide value increased in all oil samples but there was less tendency reported in oil having citrus peel extract and same trend was documented for free fatty acid (FFA). Cakes and cookies made by citrus peel extract were found better on the basis of hedonic evaluation that conducted by trained taste panel.
Conclusions: It is deducted from the present exploration that different agro-industrial wastes are rich source of natural antioxidant. There is a possibility to extract these bioactive molecules for food applications as in oil to prevent the rancidity by neutralizing free radicals produced during storage. Methanol is found a better medium for extraction of antioxidants. Sensory evaluation and oil stability inferred that citrus peel extract is better in majority of aspects than that of carrot pomace.


  • Agro-industrial wastes of fruits and vegetables should be utilized for the production of value added products especially for antioxidants to cope with life style disorders.
  • Nutrient dense products like cakes and cookies should be introduced with proven therapeutic potential.
  • Government should focus on the economical and valuable natural resources for the replacement of synthetic additives.