Ohmic heating assisted vacuum evaporation of pomegranate juice: Electrical conductivity changes
Ohmic heating assisted vacuum evaporation of pomegranate juice: Electrical conductivity changes
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DOI：
10.1016/j.ifset.2016.12.014
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发表时间：
2017-02-01
影响因子：
6.6
通讯作者：
Cokgezme, Omer Faruk
中科院分区：
文献类型：
--
作者：
Icier, Filiz;Yildiz, Hasan;Cokgezme, Omer Faruk
将一种新型的电加热方法——欧姆加热集成到真空蒸发系统中，在180 mm Hg的绝对压力下，通过施加7.5、10和12.5 V/cm的电压梯度，将石榴汁浓缩至总可溶性干物质含量达到40%。在7.5、10和12.5 V/cm电压梯度下，总蒸发时间分别为152、78和53 min。与传统蒸发法相比，欧姆加热法可使石榴汁浓缩时间缩短56%左右。7.5 V/cm时电导率为25%，10 V/cm时电导率为35%，电导率为10 V/cm时电导率呈下降趋势。而在12.5 V/cm的蒸发过程中，它是恒定的（0.55 0.01 S/m）。建议将欧姆加热方法与真空蒸发工艺相结合，显著缩短加工时间。工业相关性：欧姆加热已被用作加热、巴氏杀菌、烹饪等目的的替代方法，通过欧姆加热可以获得相对更好的产品。如今，浓缩果汁生产需要节能系统。将欧姆加热集成到传统的真空系统中，可以有效地利用能源生产出高质量的浓缩果汁。本研究成功地对石榴汁进行了欧姆加热辅助真空蒸发。这种方法减少了果汁浓缩的总过程时间，这对工业规模生产至关重要。考虑到欧姆系统的设计特点，如电导率随温度和总可溶性固形物浓度的变化，这种新方法可以应用于果汁生产线。本文还报道了电加热辅助蒸发过程中主要工艺参数电压梯度对电导率变化的影响。(C) 2017 Elsevier Ltd.版权所有。
A novel electrical heating method, named as ohmic heating, was successfully integrated to vacuum evaporation system, and pomegranate juice was concentrated until its total soluble dry matter content reached to 40% by applying three different voltage gradients (7.5, 10, and 12.5 V/cm) at 180 mm Hg absolute pressure in this system. Total evaporation times were determined as 152, 78, and 53 min at the voltage gradients of 7.5, 10, and 12.5 V/cm, respectively. The concentration time of pomegranate juice was shortened about 56% by ohmic heating relative to conventional evaporation. The electrical conductivity values were increased up to reach 25% TSDM for 7.5 V/cm and at 35% TSDM for 10 V/cm, then showed a decreasing pattern. However, it was constant (0.55 0.01 S/m) during evaporation process at 12.5 V/cm. It is recommended that the ohmic heating method could be successfully integrated to vacuum evaporation process to shorten the processing time significantly.Industrial relevance: Ohmic heating has been utilized as alternative method for the purpose of heating, pasteurization, cooking etc., and relatively better products can be obtained by ohmic heating. Nowadays, energy efficient systems are needed in concentrated juice production. The integration of ohmic heating to the conventional vacuum systems could serve the production high quality juice concentrates with efficient use of energy. In present study, ohmic heating assisted vacuum evaporation of pomegranate juice was conducted, successfully. This method decreased the total process time for juice concentration, which is critically important for industrial scale productions. This novel method can be implemented to the fruit juice production lines by taking into account of design characteristics of ohmic systems such as electrical conductivity changes depending on both temperature and total soluble solids concentration. The effects of main process parameter, named as voltage gradient, on electrical conductivity changes during electrical heating assisted evaporation process has been also reported in the present study. (C) 2017 Elsevier Ltd. All rights reserved.