Egg white microcapsules for vitamins A, D and E
What it found
In lab tests, tiny capsules made from raw hen egg white protected vitamins A, D and E through heat, moisture, UV light and baking, and released vitamin D in a simulated gut.
The work was done in the lab, not in people.
What they found
Animal and lab studies
Antibacterial activity
In lab tests, the egg white capsules broke down Micrococcus lysodeikticus bacteria, which the authors link to lysozyme in egg white. Control samples without capsules showed no change.
Protection during heating
After 20 hours in a 40 °C water bath, encapsulated vitamins A, D and E had more than 20%, 6% and 18% better recovery, respectively, than free vitamins.
Protection from UV light
After 8 hours of UV light, free vitamin A and E were significantly degraded and 60% of free vitamin D was degraded. Encapsulated vitamin D and E had more than 2-fold and 11-fold better recovery than free forms, but vitamin A showed no significant improvement. Adding a green tea and iron coating improved recovery by more than 8-fold, 2-fold and 15-fold for vitamins A, D and E, respectively, compared with free vitamins.
Survival through baking
When baked in dough at 220 °C for 15 minutes, bread with encapsulated vitamin D had 81.3% recovery, higher than bread with free vitamin D. The capsules stayed intact through kneading.
Release in simulated gut
In a simulated mouth, stomach and intestine model, more than 67% of encapsulated vitamin D reached the intestine in active form, compared with 32% for free vitamin D. The authors say this could improve vitamin D availability by more than 2-fold.
Other findings
Capsule size and shelf life
Vitamin D capsules averaged 5.2 micrometres across, and vitamin A and E capsules about 5.3 micrometres. Capsules kept their structure and size after 3 and 6 months of storage.
What the authors conclude
“The low-cost egg white shell encapsulated vitamins can improve the nutritional value of staple food products to combat maternal and child malnutrition.”
Also in their conclusions
- They say the ultrasound method successfully made vitamin-filled microcapsules from raw hen egg whites.
- They conclude that these microcapsules can protect vitamins through heat, moisture, UV light and mechanical stress, and release them slowly after eating.
- They suggest these stable microcapsules are promising for adding vitamins to staple foods to improve nutrition.
How it was done
Many vitamins are easily damaged by heat, oxygen and humidity during storage, transport and cooking, and vitamin D is scarce in natural foods. The authors wanted a simple, food-grade way to wrap vitamins so they survive these conditions and can be added to everyday foods.
They used ultrasound to form microcapsules from raw hen egg white around oil-soluble vitamins A, D and E, then coated some with a green tea and iron complex. They tested the capsules' size, shelf life, antibacterial activity, stability under heat, UV light and baking in dough, and release of vitamin D in a simulated mouth, stomach and intestine model.
What it can’t tell you
- This was lab work, not a study in people, so it cannot show how the capsules affect human health or how well vitamins are absorbed by the body.
- The simulated digestion model is not the same as a real human gut, so the release and absorption results may differ in people.
- The study did not test whether eating foods fortified with these capsules improves vitamin levels or health in anyone.
Who paid
- Conflicts
- The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
- Authors work at
- The University of Melbourne, Australia; RMIT University, Australia; Università di Roma "Tor Vergata", Italy
The paper
- Title
- Ultrasonic microencapsulation of oil-soluble vitamins by hen egg white and green tea for fortification of food
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Zhu H, Mettu S, Cavalieri F, Ashokkumar M (2021). Ultrasonic microencapsulation of oil-soluble vitamins by hen egg white and green tea for fortification of food. Food chemistry. doi:10.1016/j.foodchem.2021.129432Free full textPubMed 33714120DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error