Evaluation of pulsed electric field and conventional thermal processing on shelf life study of kokum juice (original) (raw)
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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.
Food and Bioproducts Processing, 2016
Processing of orange juice by pulsed electric fields (PEF) and heat treatments was carried out to determine the quality variables during storage of 180 days at 4 • C. Depending on the magnitude of applied electric field strength (13.82-25.26 kV cm −1), energy (10.89-51.32 J), in comparison with heat treatment (90 • C for 10 and 20 s); significant changes in pH, titration acidity, total dry matter, and browning index were found during the storage period. With no significant change in shelf-life period, the PEF processing better preserved orange juice quality than did the heat processing. Ascorbic acid content peaked with PEF-treated orange juice under the electric field strength of 17 kV cm −1 , the treatment time of 1034 s, and the energy of 17.37 J through which no significant degradation occurred during the storage with the longest half-life (1112 days). Although ascorbic acid retention of the most of the PEF processed samples was higher than that of the heat processed ones; samples processed by 10.89, 12.70 and 29.57 J energies resulted in lower ascorbic acid content than did the heat processing (90 • C for 20 s). Except for the samples treated by 43.99 and 51.32 J energies on 180th day, the PEF processing led to no hydroxyl methyl furfural formation during and at the end of the storage, unlike the heat treatment.
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.
Journal of Food Process Engineering, 2017
Fruit juices and other beverages constitute an important source of bioactive compounds, but thermal processing may reduce their contents thus decreasing natural nutritive value of foods. This has been recently led to the use of non‐thermal technologies, especially pulsed electric fields (PEF) as an interesting alternative to thermal pasteurization of beverages. Reported results show that PEF is a useful for pasteurization of fruit juices that can minimize changes in physicochemical and nutritional properties with retention of higher amounts of health‐related phytochemicals. This study presents an overview of the effect of PEF on the physicochemical (e.g., Brix, pH, viscosity, acidity, color, aroma, and flavor, etc.) and nutritional (e.g., fatty acids and free amino acids, bioactive compounds, antioxidant capacity, etc.) properties of beverages.Practical applicationsPulsed electric fields is suitable technological option for pasteurization, able to preserve valued bioactive compounds...
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.
Food and Bioproducts Processing, 2009
Thermosonication (TS) and pulsed electric fields (PEF) represent emerging technologies for liquid food preservation. In the present study shelf life and sensory attributes of orange juice were evaluated following treatment with a combination of these technologies (TS/PEF). The juice was exposed to batch TS at 55 °C for 10 min followed by continuous PEF at a field strength of 40 kV/cm for 150 micro-s. High-temperature short-time (HTST) pasteurisation (94 °C for 26 s) was used as a control. Sensory attributes (i.e. colour, odour, sweetness, acidity, flavour and overall acceptability) of different orange juices processed with TS/PEF or exposed to HTST pasteurisation were evaluated by 37 panellists using a hedonic scale (1.9 points). All sensory attributes were rated equivalent for TS/PEF- and HTST-treated juice (P>=0.05). During the shelf life study the effect of TS/PEF on selected physical properties (pH, °Brix and conductivity), microbiological activity and colour stabilitywas monitored directly after processing and following 25 °C storage up to 168 days. No significant change in the physical propertieswas detected after TS/PEF or HTST treatment during 168 days of shelf life (P>=0.05). Although the counts for both treatments were consistently within safe levels (<1000 CFU/ml) during the 168 days of storage, overall microbial counts in TS/PEF-treated juice were higher than in thermally pasteurised juice (P < 0.05). Colour attributes showed significant differences between TS/PEF- and HTST-pasteurised juice throughout the shelf life study (P < 0.05). Although promising results have been obtained further optimisation is required in order to maximise the quality of the resulting product.
Journal of Agricultural and Food Chemistry, 2001
Effects of packaging materials, storage temperature, and time on the stability of pulsed electric field (PEF) processed orange juice were investigated. Single-strength orange juice was treated with PEF at an electric field strength of 35 kV/cm for 59 µs using an integrated pilot plant scale PEF processing and glovebox packaging system. The retention of eight orange juice aroma compounds, color, and vitamin C in glass, polyethylene terephthalate (PET), high-density polyethylene, and low-density polyethylene were evaluated at 4 and 22°C for 112 days. Packaging material had a significant effect (p e 0.05) on the retention of orange juice aroma compounds, color, and vitamin C. PEF-treated orange juice had a shelf life of >16 weeks in glass and PET at 4°C.
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.
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 °...
Chemical Analysis on the Effect of Pulsed Electric Fields in Pineapple Juices Preservation
Applied Mechanics and Materials, 2014
The application of high voltage electric field for preservation of fruit juices has a promising scope in the food industry. The pulsed electric field (PEF) is an innovative non-thermal technique and free from bio-toxic effects. The technique has a viable solution of the problem yet faced in the food industry to prolong life and preserve and maintain quality with natural properties of the liquid food and beverages. In this study, we have treated the pineapples juice samples by different strengths of pulsed electric field such as 10, 20 and 30kV/cm for 5 minutes in each test. This study used new design of helix treatment chamber with three different lengths of 20, 30and 50cm. In these experiments, all samples were kept in same and normal condition with a temperature around 25-26 °a ndthe humidity was between 55 and 65%. Then the observation based on chemical tests such as pH, conductivity, salinity and total dissolved solids (TDS) was recorded for all samples before and after the test. Based on results obtained by chemical parameters suggest that the injection on pulsed electric field of 30 kV/cm by the 50 cm treatment chamber has the best effect on pineapple juices characteristic as compared to the other value. The result of this experiment is encouraging and supportive of the better way for pasteurization the pineapple juices and increasing longevity of pineapple juices.