Lactose Crystallization

Lactose crystallization is an industrial practice to separate lactose from whey solutions via controlled crystallization. Lactose, a major component of milk and whey, is used in food, dairy and pharmaceutical products. The dairy industry produces large amounts of lactose, but a significant portion of it has not been recovered from the process and is wasted. The waste of lactose is an economic loss and imposes a threat to the environment. To recover this by-product of the cheese industry derived from milk whey, massive industrial scale cooling crystallization is a trendy practice. However, the crystallization process is far from optimized.

Product quality and yield are highly dependent on particle size and the lactose crystallization process is complicated by the seasonal variability in milk quality, the presence of mineral impurities and slow crystal growth kinetics - which historically require long batch times. The majority of industrial lactose crystallization process produces relatively small crystals, resulting in the downstream separation of low efficiency and low recovery ratio.

The lactose crystallization process requires identifying mechanisms which influence the outcome:

• Nucleation (and Secondary Nucleation)
• Growth
• Oiling Out
• Agglomeration
• Breakage
• Polymorphism Chemistry

Gaining basic process understanding is the first step in optimizing the lactose crystallization process. Important steps, such as the solubility curve measurement and meta-stable zone width study, provide a fundamental understanding of crystallization thermodynamics.

A comprehensive particle engineering toolbox includes a reactor that mimics conditions at larger scales, as well as, probe-based tools that are inserted directly into the process to provide immediate and real time understanding of the impact of process parameters on the process of lactose crystallization.

Process parameters and particle mechanisms are recorded and monitored automatically and can be linked to an offline particle size analysis result. Software ties all of this information together seamlessly, allowing scientists to concentrate exclusively on using high-quality data to make excellent evidence-based decisions.

• EasyViewer is a probe-based imaging tool with image analysis, and captures high-resolution images and calculate crystal, particle and droplet size distributions as they naturally exist in process.
• ParticleTrack tracks in-situ the change in crystal size and counts. By understanding changes to particles in real time, scientists can quickly detect wanted and unwanted crystallization mechanisms, ensure batch-to-batch consistency, and optimize downstream throughput and product quality.
• Automated chemical reactors replace traditional round bottom flasks and jacketed lab reactors. These tools provide precise and automated control of an expanded range of process conditions and record parameters for analysis, repeat experiments and regulatory requirements.

• Pandalaneni, K., & Amamcharla, J. (2016). Focused beam reflectance measurement as a tool for in situ monitoring of the lactose crystallization process. Journal of Dairy Science, 99(7), 5244–5253. https://doi.org/10.3168/jds.2015-10643
• Siddique, H., Brown, C. J., Houson, I., & Florence, A. J. (2015). Establishment of a Continuous Sonocrystallization Process for Lactose in an Oscillatory Baffled Crystallizer. Organic Process Research & Development, 19(12), 1871–1881. https://doi.org/10.1021/acs.oprd.5b00127
• Li, H., Kawajiri, Y., Grover, M. A., & Rousseau, R. W. (2014). Application of an empirical FBRM model to estimate crystal size distributions in batch crystallization. Crystal Growth & Design, 14(2), 607–616. https://doi.org/10.1021/cg401484d
• Wong, S. Y., & Hartel, R. W. (2014). Crystallization in Lactose Refining-A Review. Journal of Food Science, 79(3), R257–R272. https://doi.org/10.1111/1750-3841.12349
• Chollangi, A., & Hossain, M. M. (2007). Separation of proteins and lactose from dairy wastewater. Chemical Engineering and Processing: Process Intensification, 46(5), 398–404. https://doi.org/10.1016/j.cep.2006.05.022
• Gänzle, M. G., Haase, G., & Jelen, P. (2008). Lactose: Crystallization, hydrolysis and value-added derivatives. International Dairy Journal, 18(7), 685–694. https://doi.org/10.1016/j.idairyj.2008.03.003