We have developed an economical methodology for the separation of whey proteins suitable for industrial applications (Adikane et al. 2017). This may encourage the dairy industry at large to process whey to obtain valuable products and to make it safe for disposal. Most countries have large dairy and cheese production units which generate huge amounts of whey. Whey is a watery part that remains after the coagulation of milk by acid or proteolytic enzymes and it contains mainly, lactose, proteins, minerals and water. In general, 100 L of milk produces about 12 kg of cheese or about 3 kg of casein and in either case, about 87 L of whey is made as a by-product that contain 0.57 – 0.65 percent protein and 4.7 – 5.0 percent lactose (Archer). However, land disposal of whey as a waste product has been widely practiced all over the world. That poses serious pollution problems for the surrounding environment because of its high biochemical oxygen demand 30,000- 50,000 mg/L and chemical oxygen demand of 60,000-80,000 mg/L2. Thus, it is highly essential that whey has to be process further to generate more valuable products and subsequently to make it suitable for safe disposal (Das et al. 2016).
Problem
In general, the membrane separation technique such as microfiltration and ultrafiltration are being used at industrial level for the production of proteins and lactose from whey. The membrane technology appears to be a perfect technique to remove such a low concentration molecules from huge volume as the concentration of protein (0.57-0.65%) and lactose (4.7-5.0%) is very low in whey. The use of ultra filtration for the concentration of whey protein in isolation or in combination with other membrane separation techniques has been widely reported. However, the problem associated with ultra filtration such as whey protein recovery and membrane fouling remains a major challenge (Wen-qiong et al. 2017).
Secondly, the product obtained using an ultra filtration is called whey protein concentrates (WPC), which has some undesirable properties such as high lipid and lactose content that limit its use. These undesirable properties can be eliminated using chromatography techniques and the product termed as whey protein isolate (WPI). WPI is made by adsorption of whey proteins onto ion-exchange beads. However, use of chromatography techniques enhances the product cost, primarily due to higher capital costs for building the ion-exchange plant compared to the ultrafiltration, microfiltration plant (Ayers et al. 1986).
Thus, the commercial-scale fractionation of different whey proteins has been hampered by the lack of an economical fractionation technology. The resolution and throughput of conventional chromatographic methods is too low to be economical as the whey proteins are present in small quantities and to recover a fixed amount of protein, large volumes of solution has to be processed. Secondly, as the concentration of whey protein by ultra filtration is being carried out almost on a daily basis in many industrial plants in the world. Thus, the new technology has to be compatible with existing technology available in the industry to enhance its adaptability. Considering all these factors, membrane chromatography appears to be the most appropriate technology as it is a well established technique in biomolecule separation.
However, irrespective of its technical supremacy, adaptation of membrane chromatography at commercial level operations does not go as per the expectations that may be due to some economical factors. The problem such as its high preparation cost and fouling that lead to high maintenance cost may be some reasons that holding its wide commercial utilizations. However, economy is an important factor in operations such as separation of proteins from whey. As it is a waste product management operation and secondly the market value of product is low.
What We Offer
The novelty of our invention is based on its uniqueness in the combination of ion exchange chromatography and membrane filtration device equipped with modified flow pattern. This helps to obtain whey proteins in a single process step in concentrated form using pH 7 as eluent without any additional salt, which can be directly used for freeze drying, spray drying, etc. We have used a cotton cloth as a base material to develop it into adsorbent. This ensures higher pore size, which means low fouling and high throughput, low preparation and maintenance cost in comparison with the available commercial adsorbent.
The combination of chromatography and membrane filtration technique helps in minimizing the conventional problems associated with adsorption membranes and chromatography adsorbent media. The developed adsorbent has shown 3438 ± 52.7 (mg / m2) milk whey protein adsorption. However, 2753 ± 42.5 (mg / m2) whey protein adsorption was obtained with the commercial adsorption membrane when tested under similar conditions. The preparation cost of developed adsorbent was around 18,000 Rs. / m2.
There was negligible decrease in buffer flux (543 ± 36 L / m2 / h) after 30 consecutive runs with the developed adsorbent; whereas commercial adsorbent showed almost 77percent decrease in buffer flux after 8 consecutive runs (43 ± 0.0 L / m2 / h). The product obtained using developed adsorbent will be lactose free whey protein isolates (WPI), which is not possible using a conventional membrane filtration technique that is generally being used at industrial level operations. The scale-up studies carried out suggests no problem in scalability of the present invention. The results obtained using developed adsorbent showed the 3438 mg/m2 and 8128 mg/m2 adsorption of whey proteins for 5 ml and 1000 ml operating volume respectively.
The increase in adsorption in case of 1000 ml operating volume may be attributed to the difference in membrane filtration device configurations. In case of 5 ml operating volume it was Amicon® Stirred Cell whereas flat sheet module configuration was used for 1000 ml operating volume. This clearly shows the developed adsorbent has the sufficient flexibility to accommodate as per the need of respective membrane filtration device configurations. However, prior to going for commercialization it is essential to generate a pilot plant scale data as per the requirements of end user. This will help for the successful commercialization of developed technology.
Conclusion
Our developed methodology appears to be a most economical method suitable for obtaining lactose free proteins from whey. It provides a methodology to obtain all the major whey proteins in concentrated and pure forms (Figure 1&2). Secondly, the high flux regeneration capacity with minimum washings that ensures longer life of developed adsorbent. Thus, our methodology has all the parameters that suggest its suitability for the economical separation of proteins at industrial level operations.
Acknowledgement: We thank for the financial support given by the Ministry of Food Processing Industries Government of India, New Delhi, to carry out work (76/MFPI/R&D/2011).
* Scientist (Bioengg); Chemical Engineering Div, National Chemical Laboratory,
Pune – 411 008, INDIA, Email: hv.adikane@ncl.res.in
References:
Adikane, H. V. Jagtap, M. D. (2017) Apparatus and method for separating whey proteins from whey using the same. WO patent (Appl. no. PCT/IN2017/050176; 11.05.2017).
Archer, R. H. Whey Products (https://nzic.org.nz/ChemProcesses/dairy/3G.pdf).
Das, B. Sarkar, S. Sarkar, A. Bhattacharjee, S. Bhattacharjee, C. (2016). Recovery of whey proteins and lactose from dairy waste: A step towards green waste management. Process Saf. Environ. Prot., 101, 27-33.
Wen-qiong, W. Lan-wei, Z. Xue, H. Yi, L. (2017). Cheese whey protein recovery by ultrafiltration through transglutaminase (TG) catalysis whey protein cross-linking. Food Chem., 215, 31-40.
Ayers, J.S.; Elgar, D. F.; Peterson, M. J. (1986). Whey protein recovery using Indian S, an industrial ion exchanger for proteins. N. Z. J. Dairy Sci. Technol., 21, 21-35.
Scientist (Bioengg); Chemical Engineering Div,, National Chemical Laboratory,
Pune – 411 008, INDIA, Email: hv.adikane@ncl.res.in
