Cheese whey treated by membrane separation as a valuable ingredient for barley sourdough preparation M. Sluková a,1 , A. Hinková a,⇑ , S. Henke a,1 , F. Smrz ˇ b,2 , M. Lukac ˇíková a,1 , V. Pour a,1 , Z. Bubník a,1 a Institute of Chemical Technology, Prague, Department of Carbohydrates and Cereals, Technická 5, 16628 Prague 6, Czech Republic b Zeelandia Company, Malšice 267, 39175 Malšice, Czech Republic article info Article history: Received 14 October 2014 Received in revised form 5 March 2015 Accepted 9 March 2015 Available online xxxx Keywords: Propionic acids Rejection Recovery Food preservatives Cheese whey Sourdough Diafiltration Barley Extrusion Fluid drying abstract Utilisation of cheese whey for production of healthier food has been the main task of this study. Cheese whey, which is often considered as a waste material, was treated by a series of processes including fer- mentation, membrane filtrations, mixing with barley flour, drying, and/or extrusion to produce barley sourdough. In the first series of experiments, the effect of membrane ultrafiltration (UF) and nanofiltration (NF) on separation of whey components has been studied. Non-fermented sweet cheese whey was treated by pilot-plant membrane ultrafiltration (50 kDa tubular ceramic membrane, TAMI Industries, France), fol- lowed by three step diafiltration to minimise losses of lactose, glucose, galactose, and organic acids (namely lactic acid) in retentate. The UF permeates were used for the subsequent nanofiltration and diafiltrations (spiral wound membrane NF 270-2540, Filmtec, Dow Chemicals, USA). The results showed high recovery of proteins (81%) during UF and reduction of lactose and propionate losses by using diafil- tration. Rejections of components on the NF membrane were: 93% lactose, 77% galactose, and 76% lactic acid. However, the diafiltration on the NF membrane reduced the relative recovery both for carbohy- drates and organic acids. In the second series of experiments, cheese whey was concentrated by reverse osmosis (RO) and the obtained retentate was fermented with Lactobacillus plantarum, Lactobacillus sanfranciscensis and Propionibacterium freudenreichii subsp. freudenreichii. Part of the fermented whey was mixed with barley flour and dried by cold air fluid drying to produce sourdough pellets. The other part of fermented whey was filtered by nanofiltration and both permeate and retentate were sprayed on the surface of sourdough pellets in several layers and dried again. The extrusion of a mixture containing barley flour and fermented whey was tested for pellet production as well. The main aims were to obtain sourdough rich in natural preservatives, and maintain the present microorganisms active. That is why all the technological pro- cesses, including drying, were carried out under low temperatures. The content of organic acids (lactic, acetic and propionic) was analysed in final sourdough samples. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction The technology of fermented cereal products is nearly as old as the humankind itself, and seemingly, there is not much to improve. Nevertheless, concerns about food safety and quality, nutritional properties, and positive effect on human health boosted the research even on traditional food products, such as bread. Nowadays, the attention is drawn to sourdough, as well as new types of cereals. Barley represents such cereal even though it is one of the oldest crops. Barley has been mostly used as animal feed or for malt pro- duction, and only 5% is being used in food (FAO, 2009). From a nutritional point of view, barley contains high amount (8–10%) of soluble dietary fibre in form of b-glucans (Dickin et al., 2011; Dieckmann, 2011), which are evenly distributed in the whole grain, including endosperm and pericarp (Baik and Ullrich, 2008; Holtekjølen et al., 2006). Many studies have confirmed the positive effect of b-glucans in human diet on the prevention of many life-style diseases, such as type 2 diabetes, cardiovascular diseases, obesity and high choles- terol levels (Andersson and Åman, 2011). For example, according to Collins et al. (2010), a higher dietary fibre intake reduced the risk of cardiovascular disease and myocardial infarction. Barley http://dx.doi.org/10.1016/j.jfoodeng.2015.03.023 0260-8774/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +420 220443111; fax: +420 220445130. E-mail addresses: hinkovaa@vscht.cz (A. Hinková), fsmrz@zeelandia.cz (F. Smrz ˇ). 1 Tel.: +420 220443111; fax: +420 220445130. 2 Tel.: +420 602491470. Journal of Food Engineering xxx (2015) xxx–xxx Contents lists available at ScienceDirect Journal of Food Engineering journal homepage: www.elsevier.com/locate/jfoodeng Please cite this article in press as: Sluková, M., et al. Cheese whey treated by membrane separation as a valuable ingredient for barley sourdough prepa- ration. Journal of Food Engineering (2015), http://dx.doi.org/10.1016/j.jfoodeng.2015.03.023