Moisturizing Effects of Collagen Peptides Extracted from Salmon Skin
Ming Yi (Corrine) Zhu
Crofton House
Floor Location : S 065 D

Collagen is an extracellular macromolecule, so it is difficult for human bodies to absorb collagen due to its high molecular weight. However, collagen peptides are hydrolytic products of collagen, so their molecular weights are usually less than 10, 000 Da. Collagen peptides contain all types of amino acids, and their absorption, solubility, and water retention are better than collagen itself. Collagen peptides contain a large number of hydrophilic groups, such as hydroxyl groups and carboxyl groups, exposed on the exterior of the molecules and abundant amounts of serine, glycine, aspartic acid and other moisturizing factors that can improve collagen peptides’ water retention. In addition, collagen peptides with lower molecular weights can be absorbed quickly into the skin epidermis and combine with water to form a net structure, so moisture can be trapped and absorbed by skin effectively. Therefore, collagen peptides could possibly serve as natural moisturizing factors for skin.
Recent studies primarily focus on the oral collagen peptide supplementations’ ability to improve skin elasticity and water retention (Mari Watanabe-Kamiyama, 2010). However, not many researches have studied the effects of external application of collagen peptides extracted from salmon skin, which is relatively rich in collagen proteins. This study tested the efficiency and simplification of our salmon skin collagen peptide extraction protocol and investigated the extracted peptide samples’ moisturizing effects.
Fats and impurities were first removed from the protein before collagen peptides could be extracted with protease and filtered under different conditions. Varying the protease concentration, we prepared two groups of collagen peptides, one with high molecular weight (MW) and the other with low molecular weight (MW). We then observed the samples under an electron microscope and tested the molecular weights distribution. We made the samples into solutions and then applied the solutions onto the 3M tape on slides before placing them in water bath with relative humidity of 85%. We recorded the amount of water loss every hour to test the sample’s moisturizing ability.
Our electron microscopy results showed that collagen proteins were cut into pieces of various sizes. The high performance liquid chromatography test showed that 97.6% of the fragments in the low-MW sample and only 27.8% of fragments in the high-MW sample had MW of less than 2,000 Da. This result indicated that our peptide extraction protocol was efficient. Furthermore, the low-MW sample had less water loss than the high-MW sample and the control group in the six-hour period. Thus, collagen peptides extracted from salmon skin can maintain moisture steadily. My results can have many implications. Firstly, I created an effective approach in extracting salmon skin collagen-derived peptide. Secondly, through this experiment, I concluded that moisturizing peptides exist in the hydrolyzed salmon skin. Finally, the salmon skin collagen peptides are comparatively cheap, so it has a broad application prospect in skincare products.