The dairy industry is one of the primary sources of industrial effluent. Global production of whey, the liquid remaining after milk has been coagulated and strained, is estimated at annual production of over 160 million tons, with an estimated growth rate of 1–2% yearly.
Based on the casein coagulation method this byproduct can be divided in two types: sweet and acid whey. Acid whey results from the activity of lactobacilli or by the addition of lactic acid or mineral acids and has a pH of approximately 4.3–5.1. Sweet whey typically has a pH range around 6 to 7, it occurs at cheese production by coagulating milk with rennet enzymes. While sweet whey has several commercial uses, the acid whey is often discharged into the sewage system.
This represents an enormous environmental impact as it has the potential to deplete oxygen levels in water, and poses a major risk to aquatic life, as well as to the environment and human health.
In recent years, acid whey production has increased due to a growing demand for Greek-style yogurt and acid-coagulated cheeses. The industry has long struggled to find a sustainable application for acid whey. Besides its high biological oxygen demand due to its composition, it is difficult to spray dry acid whey as most of the lactose is converted to its crystalline structure. Overall, while the primary use of acid whey is still as a feed ingredient for livestock, there are several emerging applications being explored that could lead to new opportunities for the utilization of this by-product.
During milk fermentation, some lactic acid bacteria (LAB) synthesis metabolites known as exopolysaccharides (EPS). The structure of EPS can be divided into two different groups: homopolysaccharides and heteropolysaccharides.
Hetero-exopolysaccharides (EPS) from lactic acid bacteria show a high potential for the use as thickening agents, commercially important hydrocolloids are mostly non-dairy and derived from plants (e.g., pectin, guar gum), algae (carrageenan) or fungi (pullulan).
However, the isolation of EPS is laborious and therefore not economically yet. The EPS concentration in fermented dairy products is at very low content approximately at ~ 0.02%, our aim is to improve the EPS effects. To overcome this draw back, we applied a simplified isolation protocol to a whey medium fermented with LAB resulting in isolates with different purities, macro-molecular properties and techno-functionality in model food systems.
The research project aimed to develop EPS-functionalized concentrates based on sour whey from various small scale membrane processes, which can be used instead of non-dairy hydrocolloids to improve the texture, rheology and stability of fermented milk products and ideally leads to clean-label products.