Comparative proteomic analysis of donor human milk treated by high-pressure processing or Holder pasteurization on undigested proteins across dynamic simulated preterm infant digestion
High-pressure processing (HPP) of donor human milk preserves the concentration and bioactivity of key bioactive proteins better than Holder pasteurization (HoP) and results in a protein profile after digestion that is more similar to raw milk. The study reveals that HPP-treated milk proteins are more resistant to proximal digestion, with specific undigested proteins remaining intact compared to those treated with HoP.
College of Health researcher(s)
College unit(s)
Highlights
- Study assessing how human milk pasteurization impacts protein digestion in vitro.
- Pasteurization minimally changes proteins (count, abundance) pre-digestion.
- Increased proteolysis in Holder vs. high-pressure milk during gastric phase.
- Simulated digestion of raw and high-pressure milk yields similar profiles.
- Key proteins in high-pressure milk better resist proximal digestion vs. Holder.
Abstract
High-pressure processing (HPP) of donor human milk (DM) minimally impacts the concentration and bioactivity of some important bioactive proteins including lactoferrin, and bile salt-stimulated lipase (BSSL) compared to Holder pasteurization (HoP), yet the impact of HPP and subsequent digestion on the full array of proteins detectable by proteomics remains unclear. We investigated how HPP impacts undigested proteins in DM post-processing and across digestion by proteomic analysis. Each pool of milk (n = 3) remained raw, or was treated by HPP (500 MPa, 10 min) or HoP (62.5 °C, 30 min), and underwent dynamic in vitro digestion simulating the preterm infant. In the meal, major proteins were minimally changed post-processing. HPP-treated milk proteins better resisted proximal digestion (except for immunoglobulins, jejunum 180 min) and the extent of undigested proteins after gastric digestion of major proteins in HPP-treated milk was more similar to raw (e.g., BSSL, lactoferrin, macrophage-receptor-1, CD14, complement-c3/c4, xanthine dehydrogenase) than HoP.
FAQ: High-Pressure Processing of Donor Human Milk
What is high-pressure processing (HPP), and how is it different from Holder pasteurization (HoP)?
HPP is a non-thermal pasteurization technique that uses high pressure to inactivate pathogens in food, including donor human milk. Unlike HoP, which uses heat (62.5°C for 30 minutes), HPP maintains a lower temperature, minimizing the degradation of heat-sensitive nutrients and bioactive components.
What are the benefits of using HPP to pasteurize donor human milk?
HPP better preserves many beneficial components of human milk, including:
- Bioactive proteins: Lactoferrin, bile salt-stimulated lipase (BSSL), lysozyme, and immunoglobulins
- Enzymes: Lipases, proteases
- Growth factors and hormones
- Vitamins: B6, B12, C, folate
- Other components: Volatile profile, milk fat globule membrane-associated proteins
How does HPP affect the digestion of proteins in donor human milk?
Research using a simulated preterm infant digestion model suggests that proteins in HPP-treated milk are digested similarly to raw milk. Notably, HPP milk retains higher levels of undigested lactoferrin, BSSL, and macrophage mannose receptor-1 in the stomach and duodenum compared to HoP milk. These proteins play a crucial role in infant health, including immune defense, nutrient absorption, and growth.
What is the significance of finding higher levels of undigested proteins in HPP-treated milk?
The presence of undigested proteins in the proximal digestive tract suggests that they may retain their bioactivity and contribute to infant health. For example, undigested lactoferrin can exert antibacterial and anti-inflammatory effects, while BSSL aids in fat digestion.
Does HPP impact the digestion of all proteins in the same way?
While HPP generally preserves proteins better than HoP, some differences are observed. The study found that HPP-treated milk had lower levels of undigested immunoglobulins (IgA and IgG) at the end of digestion compared to raw or HoP milk. Further research is needed to understand the implications of this finding.
What are the limitations of the study, and what future research is needed?
The study was limited by the small number of milk pools analyzed and the use of milk with a high bacterial load. Future studies should investigate a larger and more diverse set of milk samples. Additionally, clinical trials are needed to assess the impact of HPP-treated milk on infant health outcomes.
Is HPP a viable alternative to HoP for pasteurizing donor human milk?
Based on current research, HPP shows promise as a superior alternative to HoP for pasteurizing donor human milk. It preserves a wider range of beneficial components and appears to support more natural protein digestion patterns.
What is the overall conclusion of the study?
HPP offers a promising alternative to HoP for processing donor human milk, potentially leading to improved health outcomes for preterm infants who rely on donor milk. Further research, particularly clinical trials, is crucial to confirm these findings and assess the long-term benefits of HPP-treated donor milk.