Effects of Pulsed Electric Fields on the Activities of Microorganisms and Pectin Methyl Esterase in Orange Juice

• Published in: Journal of food science 2000-11, Vol.65 (8), p.1359-1363
• Main Authors: Yeom, H.W., Streaker, C.B., Zhang, Q.H., Min, D.B.
• Format: Article
• Language: English
• Subjects: Beverages; Biological and medical sciences; Citrus fruits; Food contamination & poisoning; Food industries; Food microbiology; Food processing industry; Food safety; Food science; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Microorganisms; nonthermal processing; orange juice; pectin methyl esterase (PME); pulsed electric fields (PEF)
• ISSN: 0022-1147; 1750-3841
• DOI: 10.1111/j.1365-2621.2000.tb10612.x

Orange juice was treated with pulsed electric fields (PEF) in a pilot‐plant system to optimize PEF‐processing conditions for maximum microbial inactivation and to investigate the effects of PEF on pectin methyl esterase (PME) activity. Electric‐field strengths of 20,25,30, and 35 kV/cm and total treatment times of 39, 49, and 59 μs were used. Higher electric‐field strengths and longer total treatment times were more effective to inactivate microorganisms and PME (p < 0.05). PEF treatment of orange juice at 35 kV/cm for 59 μs caused 7–log reductions in total aerobic plate count and yeast and mold counts. About 90% of PME activity was inactivated by PEF treatment at 35 kV/cm for 59 μs. PEF‐treated orange juice at 35 kV/cm for 59 ms did not allow growth of microorganisms and recovery of PME at 4, 22, and 37 °C for 112 d.