Chemical and Technological Studies on Olive and Tomato Wastes Treated by Gamma Irradiation

The present study was carried out to evaluate of utilization of some food wastes such as olive and tomato pomace which were treated by different gamma irradiation doses (0, 3, 6 and 9 kGy for olive pomace) and (0,1,3 and 5 kGy for tomato pomace), then extracted with different solvents (ethanol, methanol and acetone 75% for irradiated olive pomace) and (chloroform: ethyl acetate (1:1), methanol and acetone 70% for irradiated tomato pomace). The total phenolic content, total flavonoids content and antioxidant and antimicrobial activity properties for all extracts were assessed with different methods. The obtained data showed that, the total phenolic content increased with an increase in irradiation dose for all extractions. Extracted Phenolic content and antioxidant activity from olive and tomato pomace by using acetone was higher than those extracted by other solvents, Then the best extract (acetone extract of irradiated olive pomace at 9 kGy and irradiated tomato pomace at dose 3 kGy) was assessed for antioxidant and antimicrobial activity in produced beef sausage (by addition level 20, 40 and 60 mg GAE/kg sausage) as compared with synthetic antioxidant (BHT at 100 mg /kg sausage) and gamma irradiation treatment at dose )3 and 5 kGy( during cold storage (4±1ºC). Olive and tomato pomace extract results were satisfactory effect in protecting against lipid oxidation in beef sausage, besides were more affective as antimicrobial agent comparing with irradiation treatments. In the same time, the treatment with olive and tomato pomace extracts more effective than irradiation in maintaining the oxidative stability of samples. As for sensory acceptance, the addition of tomato and olive pomace extracts (40 mg GAE/kg sausage) was effective in maintaining the sensory properties of the beef sausage during cold storage periods at (4±1ºC)