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Abstract
Cheese whey, the liquid remaining after the separation of milk fat and casein from whole milk, is a major problem as organic pollutant for the environmental natural quality, which demands simple and economical solutions for valorization or bioepuration. The bioconversion of lactose from whey to valuable products has been actively explored. Since whey and whey permeates contain significant quantities of carbon and nitrogen compounds, an interesting way to upgrade this effluent could be as a substrate for different fermentations. Due to the large lactose content generated, its conversion to bio-ethanol has long been considered as a possible solution for whey biovalorization. Bioactive whey proteins and peptides are gradually finding more applications not only as food or feed products but also as functional compounds to be use in the pharmaceutical field.
Keywords: whey, carbon and nitrogen compounds, biovalorization, environmental protection
Introduction
Cheese making is a process concentrating milk components, in particular fat and protein contents which are determinant factors of cheese yield. It is a linear process which involves many technological steps. Nowadays are using many types of different processing methods for cheese making.
In general, the production scheme of cheese manufacturing include the following steps: production of coagulum through the enzymatic or acid coagulation by using rennet and/or lactic acid, separation of the resulting curds from the whey and then processing of the curds to obtain the desired characteristics of the cheese (Dragone et al., 2009). A flowchart of cheese manufacturing consists of seven main steps and the waste flows from each manufacturing step are presented in Figure 1.
In the first step starter cultures are added to the milk to produce lactic acid. The rennet is then used to coagulate the milk protein. The curds and whey are separated and the curds washed and cut into cubes. The firmness of the cheese involves compressing and stretching the curds and can be carried out in tower systems.
Based on its low concentration of milk constituents (6-7 % dry matter), whey has commonly been considered a waste product (Koller et al., 2008; Staniszewski et al., 2009).
As cheese production increased, the volume of whey also grew and many cheese factories were built near waterways. So that most of the whey was diverted to these...