Codfish is worldwide mostly consumed salt-cured due to the highly appreciated sensory characteristics promoted by salt. During the salting process huge amounts of salted wastewater are generated –approximately 22% w/w of the codfish – carrying ca. 250 g/L of sodium chloride and ca. 10 g/L of organic compounds, namely proteins and free amino acids. In this study, the salt load of wastewater generated during the salting process of codfish (Gadus morhua) was successfully reduced by ethanol extraction. The effects of time, sample:ethanol ratio, pH and temperature on salt extraction by ethanol addition were assessed by a onevariable-at-a-time approach and then by performing a 32 fractional factorial design. The effects of pH werealso assessed in absence of ethanol. The maximum amount of salt precipitated in the wastewater was ca. 33%, at a wastewater-ethanol ratio 1:1 (v/v), at a temperature of 0 °C and after 30 min. Proteins and free amino acids present in the wastewater significantly limited salt precipitation; in a blank solution (salt in water at ca.250 g/L) a higher amount of salt, ca. 37%, was precipitated in the same conditions. Ethanol and temperature showed a linear effect on salt precipitation for both wastewater and blank solution however ethanol was the driving factor. Changes in pH did not result in salt precipitation either in absence or presence of ethanol.During salt extraction, no precipitation of free amino acids occurred in the wastewater while ca. 1.4% of protein fell into the precipitated phase along with the salt.
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机译：由于盐引起的高度赞赏的感官特征，鳕鱼在世界范围内大多消耗盐腌制。在腌制过程中，会产生大量的腌制废水，约占银鳕鱼的22％w / w。 250 g / L氯化钠和大约10 g / L的有机化合物，即蛋白质和游离氨基酸。在这项研究中，通过乙醇萃取成功地降低了银鳕（加德摩斯）盐析过程中产生的废水的盐负荷。时间，样品：乙醇比，pH和温度对通过添加乙醇提取盐的影响的评估方法为一次可变方法，然后进行32阶乘设计。在没有乙醇的情况下也评估了pH的影响。废水中沉淀出的最大盐量约为。废水和乙醇的比例为1：1（v / v），温度为0°C且30分钟后为33％。废水中存在的蛋白质和游离氨基酸极大地限制了盐的沉淀。在空白溶液中（约250 g / L的盐水溶液）中加入更多量的盐。在相同条件下沉淀出37％。乙醇和温度对废水和空白溶液的盐沉淀均显示线性影响，但是乙醇是驱动因素。 pH的变化在无乙醇或无乙醇的情况下都不会导致盐沉淀。在盐提取过程中，废水中约无游离氨基酸沉淀。 1.4％的蛋白质与盐一起进入沉淀相。
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