Effect of High-Intensity Pulsed Electric Fields Processing and Conventional Heat Treatment on Orange−Carrot Juice Carotenoids

The inactivation kinetics of Lactobacillus plantarum was studied in orange-carrotjuice using high intensity pulsed electric fields. The results indicated that under the treatment conditions applied, 28.6, 32.0, and 35.8 kV/cm and treatment times ranging from 10.2 to 46.3 μs, the inactivation of L. plantarum obtained was up to 2.5 decimal reductions. Experimental and literature data were fitted to Bigelow, Hülsheger et al. and Peleg models and to Weibull frequency distribution function. Weibull was the one that best interpreted the data with accuracy factor values closer to 1.

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Effects of Heat and Pulsed Electric Fields on Bioactive Components and Color of Green Tea Infusions

International Journal of Food Engineering ◽

10.2202/1556-3758.1332 ◽

2008 ◽

Vol 4 (5) ◽

Cited By ~ 2

Author(s):

Mo Wang ◽

Ruijin Yang ◽

Wei Zhao

Keyword(s):

Heat Treatment ◽

Amino Acids ◽

Green Tea ◽

Electric Fields ◽

Free Amino Acids ◽

Free Amino ◽

Pulsed Electric Fields ◽

Bioactive Components ◽

Conventional Heat Treatment ◽

Tea Infusions

Green tea is an unfermented tea containing a higher quantity of bioactive components. It has received a great deal of attention due to many biological activities, such as antioxidative, anticarcinogenic and antitumour activities. However, deterioration in quality after heating processes, in particular sterilization, was technical barrier for commercial ready-to-drink green tea production. It has already been demonstrated that pulsed electric fields (PEF) processing can alternatively be applied to deliver safe and shelf-stable products. In this paper the effect of conventional heat treatment (121 oC, 3min) and PEF treatment on the bioactive components (polyphenols, catechins and free amino acids) and color of green tea infusions was studied. There was a significant (P<0.05) decline in polyphenols, total catechins and total free amino acids induced by heat treatment, and the green tea infusions darkened and became less green and deeper yellow after the heating. Compared to heat processing, PEF can efficiently retain the bioactive components and original color of green tea infusions.

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Inactivación de formas esporuladas de Bacillus subtilis mediante campos eléctricos pulsantes de alta intensidad en combinacion con otras tecnicas de conservacion de alimentos/Inactivation of Bacillus subtilis spores using high intensity pulsed electric fields in combination with other food conservation technologies

Food Science and Technology International ◽

10.1177/108201329800400105 ◽

1998 ◽

Vol 4 (1) ◽

pp. 33-44 ◽

Cited By ~ 63

Author(s):

R. Pagán ◽

S. Esplugas ◽

M.M. Góngora-Nieto ◽

G.V. Barbosa-Cánovas ◽

B.G. Swanson

Keyword(s):

Heat Treatment ◽

Bacillus Subtilis ◽

Hydrostatic Pressure ◽

Electric Fields ◽

High Intensity ◽

High Hydrostatic Pressure ◽

Pulsed Electric Fields ◽

Spore Suspension ◽

Attractive Alternative ◽

Intermediate Step

The inactivation of Bacillus subtilis spores using high intensity pulsed electric fields (HIPEF) was investigated. Spores were not inactivated when HIPEF treatment (60 kV/cm, 75 pulses) was used alone. The combination of-HIPEF and moderate temperatures around 60°C, and/or the activation of spore suspension prior to HIPEF treatment, and/or the use of up to 5000 IU/ml lysozyme, did not inactivate spores. High hydrostatic pressure (1500 atm, 30 min, 40°C) resulted in the initiation of germination of more than five log cycles in the number of spores, making them sensitive to subsequent pasteurization heat treatment, whereas they were not sensitive to subsequent HIPEF treatment at temperatures less than 40 °C. An intermediate step is needed which allows the outgrowth of spores to vegetative cells. Thus, the combination of high hydrostatic pressure and HIPEF treatment offers an attractive alternative to the stabilization of food products by heat to inactivate spores.

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