Agriculture and Food Sciences Research

Frying initiates different physical and chemical changes which can cause degradation of oil and quality of the fried food. This study was conducted to investigate and monitor the physicochemical and antioxidant properties of frying oils used by local fried food vendors in D/line-port Harcourt, Rivers State. A total of five frying oils were collected randomly during frying operations from the study area and analyzed at weekly intervals (3 weeks) for physicochemical and antioxidant properties. The results showed that all the frying oils collected were above the permissible limit for free fatty acid and saponfication value while peroxide values were within the Codex regulatory limit after three weeks of collection. The results also revealed a decrease in iodine values of the frying oils except for oil samples collected from Agudama Street and Railway close. Moisture content of all the frying oils was below the 0.3% maximum limit while smoke points were not in line with the recommended standard as all the oils had smoke points <170oC even up to the third week of collection. Increased usage of the oils during frying also resulted to a decrease in total phenolic content except for frying oil collected from Kaduna Street while a reverse was observed for total flavonoid content. The degradation in the quality of oils used by local fried food vendors in D/line, Port Harcourt during frying operations is an important health issue which could cause damaging health effects due to the toxic substances produced.