Karim Ahasanul, Aider Mohammed
Department of Soil Sciences and Agri-Food Engineering, Université Laval, Quebec, QC G1V 0A6, Canada.
Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec, QC G1V 0A6, Canada.
ACS Omega. 2020 Mar 31;5(14):8380-8392. doi: 10.1021/acsomega.0c00913. eCollection 2020 Apr 14.
The demand for production of prebiotics at a commercial scale is rising due to the consumers' growing health awareness. Whey, a coproduct of the dairy industries, is a suitable feed medium to produce a prebiotic lactulose through the isomerization of lactose under alkaline conditions. The aim of the present study was to compare the isomerization of lactose into lactulose of whey by using electroactivation technology with the chemical isomerization method using KOH as catalysis under equivalent solution alkalinity. Electroisomerization of lactose into lactulose was performed by using whey solutions of 7, 14, and 21% (w/v) dry matter under current intensities of 300, 600, and 900 mA, respectively, during 60 min with a sampling interval of 5 min. The conventional chemical method was carried out using KOH powder as catalyst at the alkalinity that corresponded to that measured in the electroactivated whey at each 5 min interval. The results showed that lactulose production was dependent on the whey concentration, current intensity, and EA time. The highest lactulose yield of 32% was achieved under a 900 mA current intensity at 60 min for a 7% whey solution. Thereafter, the EA conditions were compared to those of a conventional chemical isomerization process by maintaining similar alkalinity in the feed solutions. However, no lactulose was produced by the chemical process for the equivalent solution alkalinity as in the EA technique. These results were correlated with the solution pH, which reached the required values in a 7% whey solution with values of up to pH 11.50, whereas the maximum pH values that were obtained at higher whey concentrations were around 10-10.50, which was not enough to initiate the lactose isomerization reaction. The outcomes of this study suggest that EA is an efficient technology to produce lactulose using whey lactose.
由于消费者健康意识的不断提高，对商业规模生产益生元的需求正在上升。乳清是乳制品行业的一种副产品，是在碱性条件下通过乳糖异构化生产益生元乳果糖的合适原料介质。本研究的目的是在等效溶液碱度下，将使用电活化技术使乳清中的乳糖异构化为乳果糖的过程与使用KOH作为催化剂的化学异构化方法进行比较。在60分钟内，分别使用干物质含量为7%、14%和21%（w/v）的乳清溶液，在电流强度为300、600和900 mA的条件下，以5分钟为采样间隔进行乳糖的电异构化生成乳果糖。传统化学方法是使用KOH粉末作为催化剂，在与每隔5分钟电活化乳清中测量的碱度相对应的碱度下进行。结果表明，乳果糖的产量取决于乳清浓度、电流强度和电活化时间。对于7%的乳清溶液，在900 mA电流强度下60分钟时，乳果糖的最高产率达到32%。此后，通过在进料溶液中保持相似的碱度，将电活化条件与传统化学异构化过程的条件进行比较。然而，对于与电活化技术中等效溶液碱度相同的情况，化学过程未产生乳果糖。这些结果与溶液pH值相关，在7%的乳清溶液中，pH值达到所需值，最高可达11.50，而在较高乳清浓度下获得的最大pH值约为10 - 10.50，这不足以引发乳糖异构化反应。本研究结果表明，电活化是一种使用乳清乳糖生产乳果糖的有效技术。
