54F-3

C. SÁNCHEZ-MORENO¹, L. Plaza¹, P. Elez-Martínez², O. Martín-Belloso³, B. De Ancos¹, and M. P. Cano¹. (1) Plant Foods Science and Technology Dept., Instituto del Frío-CSIC, José Antonio Novais 10, Ciudad Universitaria, Madrid, 28040, Spain, (2) Food Technology Dept., UTPV-CeRTA, University of Lleida, Av. Alcalde Rovira Roure 191, Lleida, 25198, Spain, (3) Food Technology Dept., UTPV-CeRTA, Univ. of Lleida, Av. Alcalde Rovira Roure 191, Lleida, 25198, Spain

It is necessary to know the effect of refrigerated storage on the bioactive compounds and antioxidant characteristics of foods processed by emerging technologies. Orange Juice (OJ) is an excellent source of vitamin C. OJ is traditionally pasteurized by heat treatment. Vitamin C is vulnerable to air and heat. Therefore, it is important to develop new technologies that minimize the conservation processes and guarantee the microbiological safety. High-Pressure (HP) treatment reduces microbial counts and enzyme activity and offers new advantages to process fresh fruit/vegetable juices minimizing chemical changes. Pulsed Electric Fields (PEF) processing is being extensively studied as a nonthermal food preservation method. PEF processing is very effective for the pasteurization of fruit juices. Our objective was to evaluate the effect of refrigerated storage (4º C/40 days) of OJ processed by new emerging technologies (HP=400 MPa/40º C/1 min), and PEF (35 kV/cm/750 µs/800 Hz) in comparison with OJ processed by traditional technology (low pasteurization=70º C/30 s). Carotenoids analyses were conducted after extraction of saponified extract by HPLC. Flavanones and vitamin C were determined by HPLC. The antioxidant activity was evaluated by the measurement of the DPPH^• radical scavenging. After 40 days at 4º C, the OJ treated by HP showed significantly higher carotenoid content than the untreated OJ, whereas low pasteurized and PEF-treated OJs did not show significant difference. However, in all the OJs treated, we found a significant decrease in the flavanones during the storage. At the end of the refrigerated storage, regarding vitamin C and antioxidant activity, OJ treated by HP and low pasteurization showed similar vitamin C losses (14% and 18%, respectively), and did not showed significant losses in antioxidant activity compared with the untreated OJ. HP and PEF processing retained the antioxidant characteristics of the untreated OJ after a refrigerated storage at 4º C for 40 days.

Session 54F, Nonthermal Processing: General I
2:00 PM - 5:30 PM, Monday PM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana