Casein Powder Processing: A Guide for Food Processing Consultants and Manufacturers

Overview

Casein is the primary milk protein, making up nearly 80% of the total nitrogen content in milk. It plays a pivotal role in food processing and nutrition, offering a complete source of essential amino acids. Found predominantly in cow’s milk, casein serves not only the food manufacturing industry but is also extensively used in textile, paint, leather, and paper production.

For any food processing consultant or dairy technologist, understanding the intricacies of casein extraction and processing is crucial to deliver high-quality, shelf-stable protein products.

SEPARATION OF CASEIN

Casein is separated from milk by increasing its acidity, using:

Direct addition of acid (e.g., hydrochloric acid)
Biological fermentation via lactic acid bacteria such as Streptococcus thermophilus and Lactobacillus bulgaricus

The resulting casein curd can be transformed into caseinate by re-dissolving it in alkaline solutions like sodium hydroxide. This is common practice in dairy processing plants and food manufacturing facilities.

DRY CASEIN PRODUCTION:

Two types of caseins are there; Rennet casein and Acid casein.

Acid casein can be easily formed by making the skimmed milk acidic until it reaches the isoelectric point (pH± 4.6). For Rennet casein, the process used will be enzymatic coagulation. Both of these products are created by the effect of a reaction between the acid casein curd and acid casein powder with alkali (sodium hydroxide).

Caseinate is used more often in comparison to casein when it comes to its use in food industries because casein is less soluble than caseinate.

ACID CASEIN

Raw Material

Use low-fat, properly skimmed milk

Ensure pasteurization at 72°C for 15–20 seconds

Avoid overheating to prevent darkened casein

Pasteurizing

The raw skimmed milk should be pasteurized for 15-20 seconds at a temperature of 72deg.c.

Acidification

Inorganic Acidification: Add HCl to reduce pH to 4.3–4.6 and heat to 40–45°C

Biological Acidification: Add mesophilic cultures; maintain 25°C and allow 15 hours for gradual pH drop

Decanter and Washing

Decanter centrifuges remove whey efficiently

Use three-stage counter-current washing at 35°C to 60°C

Final product: ~45% dry matter

Drying

Hot air drying to reduce moisture content to 12%

Two-stage drying recommended: 50–55°C followed by 65°C

Grinding

Final casein powder is ground to sizes of 0.32mm, 0.42mm, or 0.64mm

Thinning

Rehydrate acid casein to 18–24% dry matter

Wet grind at <45°C to avoid agglomeration

Preheating and Drying

Preheat to 80–90°C for sprayability
Use spray drying towers (200–230°C) and fluidized bed dryers
Final moisture content: 10–12%

Alkalization and pH Control

Adjust to pH 6.7 using:

Sodium hydroxide for sodium caseinate
Calcium hydroxide/ammonia for calcium caseinate

Conclusion

The processing of casein powder—from separation and drying to conversion into caseinates—plays a critical role in the food manufacturing and dairy industries. With its high nutritional value, slow digestion rate, and wide industrial applications, casein is more than just a protein—it’s a strategic ingredient in both food product development and nutraceutical innovation.

For any food consultant, food processing consultant, or engineering consultancy involved in dairy plant design or protein ingredient optimization, understanding the nuances of acid and rennet casein production is essential. When coupled with hygienic plant design and precise process control, casein manufacturing offers opportunities to enhance product quality, extend shelf life, and meet global food safety standards.

By leveraging expert insights and adhering to engineering best practices, businesses can achieve operational efficiency while delivering high-quality dairy proteins that meet the evolving demands of the global food market.

Reference

Tetra Pak Dairy Handbook

GEA Casein Production Line

ScienceDirect: Casein

YouTube Video

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Overview

Conclusion

Reference