32-4 |
Pulsed electric field processing to improve the freshness of orange and tomato juices |
D. B. MIN and Q. H. Zhang. Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., Rm. 110, Columbus, OH 43210 Pulsed electric field processing (PEF) has been studied as a nonthermal food processing method to maintain or improve the freshness of foods during storage. The effects of PEF processing on microorganisms, flavor, enzyme, vitamin C, color and texture of orange and tomato juices were studied during storage at 4 and 22°C. PEF achieved 6-log reduction of microorganisms in the juices. The juices were microbiologically stable for more than 16 weeks at 4°C. PEF inactivated 88% of pectin methyl esterase in orange juice and 65% of lipoxygenase in tomato juice PEF processed orange and tomato juices retained more flavor compounds and vitamin C than those of heat pasteurized juice at 94.6°C for 30s during storage at 4°C (P<0.05). The PEF processed juices had lower browning index and better color stabilities than the heat pasteurized orange and tomato juices during storage at 4°C (P<0.05). PEF processed tomato juice produced less 5-hydroxymethyl-2-furfural and retained more lycopene content than the thermally processed tomato juice during storage. The PEF orange juice had a smaller particle size than the heat pasteurized orange juice (P<0.05). Sensory score of PEF processed juices were significantly better than those of the thermally processed juices (p<0.05). The PEF processed orange and tomato juices had better flavor quality and stability, sensory quality, color, browning index, and more vitamin C than the thermally processed juices during storage (P<0.05). PEF nonthermal processing is one of very viable and effective processing methods to improve the freshness of liquid foods during storage.
Session 32, Refreshing the fresh concept
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