Pulsed electric fields as an alternative to thermal processing for preservation of nutritive and physicochemical properties of beverages: A review (original) (raw)
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Foods
Novel pulsed electric field (PEF) process conditions at moderate electric field strength and long pulse duration have recently been established to obtain microbial inactivation. In this study, the effect of these PEF conditions (E = 0.9 and 2.7 kV/cm, with pulse duration 1000 µs) at variable maximum temperatures was evaluated on quality attributes of freshly squeezed orange juice. Results were compared to orange juice that received no treatment or a mild or severe thermal pasteurization treatment. No differences for pH and soluble solids were found after application of any treatment, and only small differences were observed for color and vitamin C content (ascorbic acid and dehydroascorbic acid) after processing, mainly for conditions applied at higher temperature. Variations in the maximum temperatures of the PEF and thermal processes led to differences in flavor compounds and the remaining activity of pectinmethylesterase (PME). At PEF conditions with a maximum temperature of 78 °...
Molecules
The deactivation of degrading and pectinolytic enzymes is crucial in the fruit juice industry. In commercial fruit juice production, a variety of approaches are applied to inactivate degradative enzymes. One of the most extensively utilized traditional procedures for improving the general acceptability of juice is thermal heat treatment. The utilization of a non-thermal pulsed electric field (PEF) as a promising technology for retaining the fresh-like qualities of juice by efficiently inactivating enzymes and bacteria will be discussed in this review. Induced structural alteration provides for energy savings, reduced raw material waste, and the development of new products. PEF alters the α-helix conformation and changes the active site of enzymes. Furthermore, PEF-treated juices restore enzymatic activity during storage due to either partial enzyme inactivation or the presence of PEF-resistant isozymes. The increase in activity sites caused by structural changes causes the enzymes t...
Journal of Food Process Engineering, 2016
Effects of pulsed electric fields (PEF) processing on physical properties, bioactive compounds, and formations of furfural and hydroxylmethylfurfural (HMF) were determined for apple juice. A central composite design to determine the optimal number and order of experimental runs and the best-fit multiple nonlinear regression (BF-MNLR) models to quantify and predict rates of change in the response variables as a function of the PEF processing were used. No significant difference was detected between the control and PEF-treated apple juice in terms of physical properties, organic acids, and polyphenols of (2)-epicatechin, caffeic acid, p-coumaric acid, ferrulic acid, quercetin, and gallic acid. The highest predictive power (R 2 pred) belonged to a* (88%), (1)-catechin (90.7%), and HMF (93.8%). Except for chlorogenic acid, no significant decrease was detected in the initial concentrations of the bioactive compounds. PEF processing provided retention of quality attributes and bioactive compounds without significant formation of furfural and HMF. Practical applications Heat processing causes degradation of bioactive compounds, changes in physical properties, and formation of undesirable compounds in apple juice; however, PEF processing provided the preservation of most bioactive compounds without significant changes in physical properties. Thus, findings in this study revealed that PEF processing is a viable option for fruit juice industry, especially, for apple juice pasteurization. 1 | INTRODUCTION The consumption of apple juice, one of the most popular fruit crops, reached 76 million tons globally and 15 million tons in Europe in 2012 (FAOSTAT, 2013). Apple juice plays an important role in human nutrition owing to its high level of antioxidants, phenols or phenolic compounds that may defend humans against free radical damage, thus reducing the incidences of coronary heart disease and cancer (Lee, Hwang, & Ha, 2003). Heat processing is the most common processing method commercially applied to fruit juices (Aadil et al., 2015). However, the deterioration of juice quality, flavoring agents, and compounds with antioxidant properties during the heat processing have oriented consumer preferences towards minimally processed fresh-like juices with enhanced nutritional and sensory properties. Thus, many studies have focused on novel nonthermal pasteurization technologies of fruit juices including pulsed electric fields (PEF) with different magnitudes of electric field strength (Evrendilek & Varzakas, 2015). There are numerous studies about effects of PEF on bioactive compounds, enzyme and microbial inactivation, physical and sensory properties, and shelf life extension (
Food Control, 2011
A response surface methodology was used to determine the combined effect of HIPEF critical processing conditions on vitamin C, anthocyanins and antioxidant capacity of strawberry juice. Keeping constant the electric field strength at 35 kV/cm and the treatment time at 1000 ms, the treatments were set at frequencies from 50 to 250 Hz, pulse width from 1 to 7 ms using monopolar or bipolar mode. A second order response function covering the whole range of experimental conditions was obtained for each healthrelated compound. Strawberry juice antioxidant potential was affected linearly by frequency, pulse width and pulse polarity. The quadratic term of frequency and the combined effect of frequency and pulse width were also significant. HIPEF treatments conducted at 232 Hz with bipolar pulses of 1 ms led to strawberry juices with the greatest presence of health-related compounds. The evaluation of the HIPEF critical parameters influence on health-related compounds can contribute to achieve optimal processing conditions to obtain strawberry juices with high antioxidant potential.
Innovative Food Science & Emerging Technologies, 2008
The effect of high-intensity pulsed electric fields (HIPEF) on the Salmonella Enteritidis and Escherichia coli O157:H7 populations inoculated in apple, pear, orange and strawberry juices as influenced by treatment time and pulse frequency was investigated. Combinations of HIPEF (35 kV/cm, 4 μs pulse length in bipolar mode without exceeding 40°C) with citric acid or cinnamon bark oil against these pathogenic microorganisms in fruit juices were also evaluated. Treatment time was the more influential factor on the microbial reduction in all the fruit juices analyzed. S. Enteritidis and E. coli O157:H7 were reduced by more than 5.0 log 10 units in orange juice treated by only HIPEF; whereas strawberry, apple and pear juices were pasteurized when HIPEF was combined with citric acid at 0.5, 1.5, 1.5%, respectively, or cinnamon bark oil at 0.05, 0.1 and 0.1%, respectively. Synergistic and additive killing effects against S. Enteritidis and E. coli O157:H7 in fruit juices by combining treatments were observed.
Lwt - Food Science and Technology, 2010
A response surface methodology was used to determine the combined effect of HIPEF critical processing conditions on vitamin C, anthocyanins and antioxidant capacity of strawberry juice. Keeping constant the electric field strength at 35 kV/cm and the treatment time at 1000 ms, the treatments were set at frequencies from 50 to 250 Hz, pulse width from 1 to 7 ms using monopolar or bipolar mode. A second order response function covering the whole range of experimental conditions was obtained for each healthrelated compound. Strawberry juice antioxidant potential was affected linearly by frequency, pulse width and pulse polarity. The quadratic term of frequency and the combined effect of frequency and pulse width were also significant. HIPEF treatments conducted at 232 Hz with bipolar pulses of 1 ms led to strawberry juices with the greatest presence of health-related compounds. The evaluation of the HIPEF critical parameters influence on health-related compounds can contribute to achieve optimal processing conditions to obtain strawberry juices with high antioxidant potential.
During the last decades pulsed electric field (PEF) processing received considerable attention due to its potential to enhance food products or create alternatives to conventional methods in food processing. It is generally acknowledged that PEF processing can deliver safe and chill-stable fruit juices with fresh-like sensory and nutritional properties. Relatively low-processing temperature and short residence times can achieve highly effective inactivation of microorganisms while retaining product quality. A first commercial application of PEF for preservation of fruit juices was launched in 2006 in the United States. Since then, industrial-scale processing equipment for liquid and solid products were developed and, in Europe in 2009, an industrial juice preservation line was installed using 20 kV/cm pulses at 40 to 50 • C to extend the chill-stability of fruit juices, including citrus juices and smoothies, from 6 to 21 d. The related PEF processing costs are in the range of US $0.02 to 0.03 per liter and are justified due to access to new markets and reduced return of spoiled product. However, despite its commercial success there are still many unknown factors associated with PEF processing of fruit and citrus juices and many conflicting reports in the literature. This literature review, therefore, aims to provide a comprehensive overview of the current scientific knowledge of PEF effects on microbial, enzymatic, nutritional, and sensory quality and stability of orange juices.
2017
Pulsed electric field (PEF) treatment is one of the non-thermal methods of food processing. PEF technology has been reported and recognized by a number of food researchers as an alternate method of conventional thermal processing for fluid and semi-fluid foods. Recently, the PEF technique application has been exploited in the field of extraction of bio-molecules, drying enhancement and enzyme activity modification. PEF has also proved significant and more effective application with moderate thermal treatment for food preservation as hurdle technology. Although significant work was found in the domain of milk and fruit juice processing and preservation, but limited reported work was found in the area of application of PEF for vegetable juice processing while no reported work was found on PEF treatment of mint and curry leaves juices. This paper reports about application of PEF and its effects in sensory qualities of the vegetable juices after a specified treatment. Few vegetable juic...
Food Chemistry, 2011
The effects of high intensity pulsed electric fields (HIPEF) (35 kV/cm with 4 ls bipolar pulses at 200 Hz for 800 or 1400 ls) or thermal (90°C, 60 s) treatments over phenolic and carotenoid compounds of a fruit juice-soymilk (FJ-SM) beverage stored at 4°C were evaluated and compared, having the untreated beverage as a reference. Coumaric acid, narirutin and hesperidin were the most abundant phenolic compounds in the FJ-SM beverage, while the main carotenoids were lutein, zeaxanthin and b-carotene. Immediately after HIPEF or heat processing, hesperidin content of the beverage showed a huge rise, resulting in a significant increase on the total phenolic concentration. Regarding carotenoid concentration, HIPEF or thermal treatment lead to a significant decrease; lutein, zeaxanthin and b-cryptoxanthin being the most affected compounds. In contrast, the content of some individual phenolics and carotenoids increased with time, while others tended to decrease or remained with no significant changes with regards to their initial values. Total phenolic concentration seemed to be highly stable during storage; while, total carotenoid content gradually diminished, irrespectively of the treatment applied. Overall, the changes observed in HIPEF treated FJ-SM beverage were less than those in the heat processed one. Hence, HIPEF is a feasible technology to obtain FJ-SM beverages with extended shelf-life and a similar profile of antioxidant compounds to freshly made beverages.
Effect of pulsed electric field treatment on shelf life and nutritional value of apple juice
Journal of Food Science and Technology, 2019
The aim of this study was to assess shelf life and nutritional value of apple juice, including the content of bioactive compounds, after pulsed electric field (PEF) treatment, taking into account different number of cycles: 4, 6, 8 (total 200, 300, and 400 pulses, respectively). Determination of vitamin C and polyphenols concentration, antioxidant activity as well as microbiological analysis were conducted immediately after PEF process and after 24, 48 and 72 h of storage. The results showed that PEF did not affect the content of bioactive compounds. PEF-treated juice did not show changes in the amount of vitamin C and total polyphenols during the storage for 72 h under refrigeration. PEF treatment was effective method for inactivation of a wide range of most common food spoilage microorganisms. PEF process can be used as an effective method of food preservation, allowing prolongation of shelf life and protection of nutritional value. This brings new opportunities for obtaining safe, healthy and nutritious food.