Casein hydrolysate

Milk protein that has been broken down by enzymes into smaller peptides to improve digestibility and reduce allergenicity.

Should I eat Casein hydrolysate?

Casein hydrolysate is a processed milk protein broken into small peptides that delivers complete nutrition. When extensively hydrolyzed and clinically proven, it can be used in hypoallergenic formulas; otherwise, its suitability varies by product.

Summary

This ingredient provides all essential amino acids with excellent protein quality and is widely used in medical and specialized nutrition. Regulators review specific hydrolysates for infant formulas and have affirmed nutritional safety when strict specs are met. Importantly, hypoallergenic status is not universal—residual allergenic proteins can vary depending on processing, so clinical validation matters. Hydrolysis can make products taste bitter, and hydrolysates made from caseinates may contribute sodium, which is relevant if you monitor salt. For most healthy adults, it is a solid protein option; those managing milk allergy should use only products proven hypoallergenic.

Key Research Benefits

Complete, high‑quality protein

Casein supplies all essential amino acids, with DIAAS values above 100 in research models, supporting growth and maintenance.

Option for milk‑allergic infants when proven

Extensively hydrolyzed casein that meets clinical criteria is considered hypoallergenic and has been judged nutritionally safe and suitable for infant and follow‑on formula.

Peptides may absorb quickly

Breaking proteins into smaller peptides can speed uptake, which is why hydrolysates appear in clinical and sports nutrition, though benefits versus intact proteins vary by product.

Key Research Risks

Not all hydrolysates are hypoallergenic

Hypoallergenicity depends on the degree of hydrolysis and clinical testing; suitability must be confirmed for each product, especially for infants with cow’s milk allergy.

Residual allergens possible

If hydrolysis or manufacturing controls are insufficient, trace allergenic proteins can remain.

Possible added sodium and bitterness

Some hydrolysates made from caseinates contain sodium, and hydrolysis tends to produce bitter peptides that can affect palatability.

Overview

What is it?

Source: Cow's milk

Method: Isolate casein, then enzymatically hydrolyze and dry

Processing Level: 9 / 10

Why is it used?

Purpose: Dairy protein broken into peptides to reduce milk‑allergen reactivity and improve digestibility.

Commonly found in: Infant formula, Protein bars, Medical shakes, Sports drinks, Meal replacements

Why manufacturers choose it: It delivers complete, high‑quality protein with reduced allergenicity and reliable performance in medical and sports formulas.

Origin

Casein, the main protein in cow’s milk, has been isolated for more than a century for use in foods. Enzymatically hydrolyzed casein—created by breaking casein into smaller peptides—became prominent in the late 20th century for hypoallergenic infant formulas and clinical nutrition when research showed that extensive hydrolysis can reduce milk-allergen reactivity while preserving protein nutrition.

Process: Isolate casein, then enzymatically hydrolyze and dry

Steps

1. Separate milk: Skim and clarify milk to obtain the protein fraction.

2. Isolate casein: Precipitate casein (acid or rennet), wash and neutralize to casein/caseinate.

3. Dissolve: Rehydrate casein/caseinate in controlled conditions.

4. Enzymatic hydrolysis: Apply food-grade proteases to cleave casein into peptides.

5. Enzyme inactivation: Heat-treat to stop hydrolysis and ensure safety.

6. Filter & polish: Remove insolubles; optionally de-bitter and demineralize.

7. Dry & mill: Spray-dry to a free-flowing powder and sieve.

Chemicals

Food-grade proteases

Research & Safety

Research Summary

Casein hydrolysate is made by using enzymes to break the main milk protein (casein) into smaller peptides. Regulators such as EFSA review specific hydrolysates for infant and follow‑on formulas and have found some to be nutritionally safe and suitable when they meet strict specifications. The FDA explains that only extensively hydrolyzed, clinically tested formulas are considered hypoallergenic for cow’s milk allergy. Studies consistently rank casein as an excellent‑quality protein (DIAAS >100), meaning it supplies indispensable amino acids well. Analytical work shows that residual allergenic fragments can persist if hydrolysis or manufacturing controls are inadequate, so hypoallergenic status is product‑specific rather than a blanket property of all hydrolysates. Hydrolysis frequently generates bitter peptides, and taste‑management steps are often needed; products made from caseinates may also carry sodium from the salt form used.

Digestive Effects

Peptides from hydrolysates are generally absorbed quickly, which can reduce the digestive workload compared with intact proteins for some users. Most people tolerate typical serving sizes well. Large bolus intakes of any protein powder may cause transient bloating, nausea, or loose stools, especially on an empty stomach or without enough fluid. People who know they are highly sensitive to dairy proteins should consult their clinician about whether a specific, clinically validated hydrolysate is appropriate.

Limit Consumption

For infants with confirmed cow’s milk allergy, only use formulas that are explicitly labeled extensively hydrolyzed and have clinical evidence of hypoallergenicity; follow pediatric guidance. Children and adults with severe milk allergy should rely on products that specify their hydrolysis level and intended medical use, as residual proteins can vary by brand. Vegetarians can use casein hydrolysate, but it is not suitable for vegans because it is dairy‑derived. People monitoring sodium (e.g., for hypertension) should check labels because hydrolysates from caseinates may contribute sodium.

Fact Sheet

Regulatory Status

US FDA: Used as a protein source in foods; extensively hydrolyzed proteins used in hypoallergenic infant formulas per FDA framework (21 CFR 107; product-specific).

EU Status: Permitted as a protein source; EFSA assesses specific hydrolysates for infant and follow-on formula on a dossier basis.

Codex INS: None (casein and caseinates are standardized ingredients; hydrolysates are protein ingredients, not assigned INS numbers).

JECFA ADI: Not specified (protein ingredient; ADI not applicable).

ESG & Sustainability

Environmental Footprint: Dairy-derived; generally higher GHG and land use than plant proteins.

Sustainability: Impacted by dairy farming practices; sourcing from lower-impact dairy may reduce footprint.

Animal Welfare: Depends on dairy supply-chain standards and certifications.

Carbon Footprint: Higher than plant proteins on average; varies by region and practices.

Allergens and Diet

Allergen Status: Milk

Diet Compatibility: Vegetarian, Gluten-free

Natural Alternatives

Whey protein concentrate

Source: Cow’s milk whey

Processing Level: Moderate

Common Uses: Shakes, bars, powders

Replacement Benefit: Complete protein with high DIAAS and generally neutral taste.

Why it's not used: Whey is not hypoallergenic; casein hydrolysate is chosen for reduced allergenicity in specific populations.

Milk protein isolate

Source: Cow’s milk

Processing Level: Moderate

Common Uses: Bars, ready-to-drink shakes

Replacement Benefit: Intact high-quality dairy proteins with calcium and phosphorus.

Why it's not used: Intact proteins can trigger milk allergy; hydrolysates reduce allergenicity.

Soy protein isolate

Source: Soybeans

Processing Level: Moderate

Common Uses: Bars, shakes, meat analogs

Replacement Benefit: Dairy-free alternative suitable for milk-avoidant diets.

Why it's not used: Casein hydrolysates offer higher DIAAS and are designed for hypoallergenic infant formulas where soy may be unsuitable.

Citations

Infant Formula

2025-05-13

U.S. Food & Drug Administration • FDA

Nutritional safety and suitability of a specific protein hydrolysate for use in infant and follow-on formula

2025-03-05

EFSA NDA Panel • EFSA Journal

Multi-criteria assessment of pea protein quality in rats

2021-07-23

Guillin FM, et al. • PubMed

Real ileal amino acid digestibility of pea protein compared to casein

2022-04-08

Guillin FM, et al. • Food Chemistry

Nutritional safety and suitability of a specific protein hydrolysate for use in infant and follow-on formula (earlier opinion)

2023-07-18

EFSA NDA Panel • EFSA Journal

Strategies for oral delivery of bioactive peptides with focus on food-derived peptides

2023-05-31

Mirzapour-Kouhdasht A, et al. • Nature npj Science of Food

Codex Standard for Edible Casein Products (CXS 290-1995)

2014-01-01

Codex Alimentarius Commission • Codex Alimentarius

Pediatric Formulas: An Update

2024-07-01

American Academy of Pediatrics • Pediatrics in Review

Determination of Casein Allergens in Extensively Hydrolyzed Infant Formulas

2020-08-17

Hostetler GL, et al. • PMC

Characterization of bitter peptides in casein hydrolysates

2023-01-15

Höhme L, et al. • Food Chemistry / Sensory