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Electric field applications on dried key lime juice quality with regression modeling
Author(s) -
Altemimi Ammar,
Ali Haider I.,
AlHiIphy Asaad R. S.,
Lightfoot David A.,
Watson Dennis G.
Publication year - 2018
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/jfpp.13637
Subject(s) - chemistry , food science , phytochemical , lime , ascorbic acid , biochemistry , biology , paleontology
Abstract Key lime ( Citrus aurantifolia L.) is an important source of juice and vitamins. A continuous nonthermal juice pasteurizer (CNTJP) using electric field with alternating current was designed and constructed. The effect of electric field was investigated on dried (black) lime juice using voltage gradients ( X 1 ) of 24–88 V/cm and mass flow rates ( X 2 ) of 12–50 kg/hr. The treated juice was evaluated for physicochemical properties, phytochemical compounds with antioxidant capacity, and microbial quality. The results showed that there were no significant effects ( p > .05) between CNTJP treatment and both the thermal treatment and the control sample regarding the total soluble solids and pH values. However, the titration acidity value of dried juices in thermal treatment was significantly higher ( p < .05) compared to the control and CNTJP samples. There was a significant difference ( p < .05) between CNTJP samples and both the control and the thermal treatment samples regarding the total phenolic content, ascorbic acid content, and antioxidant activity (1,1‐diphenyl 2‐picrylhydrazyl). Also, the results showed that coliform bacteria, yeast, and mold were not capable of growing in control samples (fresh juice) or all samples treated by CNTJP treatments or thermal treatments. However, the total viable count of CNTJP samples varied between 1.93 and 4.79 (Log10 CFU/mL), whereas the total viable counts of the control sample and thermal treatment were 5.99 and 3.82 (Log10 CFU/mL), respectively. At the optimum conditions of mass flow rate of 28.24 kg/hr and voltage gradient of 82.38 V/cm, the highest electrical conductivity was 0.65 S/m. Practical applications Nonthermal, high‐throughput pasteurization systems are highly desirable as alternatives to overcome the negative effects of thermal pasteurization. Electric field (EF) is one potential alternative technology. Although this study did not focus on effectiveness of log reduction of pathogens, EF resulted in fewer pathogenic indicators than nontreated dried lime juice. Electric field did demonstration superiority over thermal pasteurization for maintaining total phenolic content, ascorbic acid, and antioxidant activity in dried lime juice. Maximizing healthy characteristics of fruit juice during pasteurization can lead to a product with a higher retail value than traditional thermal processing. This potential higher economic value for EF‐treated juice could offset implementation and processing costs. The EF system described in this study can be readily scaled up by having parallel lines of size similar to this study or by increasing the tubing and electrode sizes or both.