Create biobased peptides and determine their mechanisms as ice recrystallization inhibitors

Non-technical Abstract:

Ice recrystallization, where large ice crystals replace small ones, is a critical problem that impacts quality and functional property of biomaterials, such as food, biomedical tissues, and cell cultures during freezing storage. Ice recrystallization inhibition (IRI) is the restriction of the growth of ice crystals caused by fluctuations in freezing temperature.

Although synthetic chemicals can be used as ice growth inhibitors, their wide application is limited due to toxicity. This research, based on exciting preliminary findings, aims to understand how peptides obtained from hydrolysis (breakdown due to reaction with water) of food proteins can act as an IRI agent and how minor structural modification will enhance such effect.

The research will address the relationship between molecular structure and IRI activity so that the mechanism of action can be better understood. These bio-based peptides are expected to have adequate IRI activity and low toxicity. They will have a wide range of applications in the food industry (increasing quality of frozen foods), agriculture (increasing resistance of plant to freezing temperatures), medicine (cold storage of cells and tissues), and material technology (deicing road or aircraft and climate control).

The knowledge gained and evaluation tools established from this study will provide insights to future fundamental biomaterial chemistry research. This project will provide STEM education to underrepresented graduate and undergraduate students. The training will increase students’ understanding of the role of fundamental chemistry in advancing science through addressing the current challenges and needs.

It will have a long-lasting impact on the students’ appreciation of applying basic knowledge in problem-solving. The students will also grow in key skills to become future biomaterial researchers through leadership training, and introduction to FDA and EPA regulations of new bio-based compounds and intellectual property protection and technology adoption.

Successful recruitment and training of minority students will diversify student profile in the department and college and create an inclusive and enriching environment for all. Technical Abstract:

Ice recrystallization and growth during freezing storage is a critical challenge that remains to be addressed. Bio-based and safe compounds are urgently needed to avoid the toxicity of synthetic anti-freezing agents. Based on the exciting earlier findings of the investigators’ group, this project aims to investigate ice recrystallization inhibition (IRI) using peptides that are derived from common food proteins through biocatalyzed hydrolysis and amidation reactions.

The relationship among peptides’ structure, physicochemical properties, and IRI activity will be established. The fundamental understanding of how peptides’ H-bonding ability and their amphiphilicity affect IRI activity will be gained. The ice-water interfacial behaviors influenced by peptides will be studied using a novel vibrational sum frequency generation spectroscopic method.

Therefore, this research addresses what is currently unknown in the field, i.e., how the bio-based peptides’ molecular characteristics relate to their IRI activity. Although theories of IRI have been tested for some pure compounds, little is known about peptide mixtures from common proteins. The structural diversity of proteins and peptides has made the structure-function studies challenging, and this is to be addressed by studying group characteristics in this work.

The proposed quantification of H-bond and amphiphilicity as the key factors for IRI activity is a novel angle for IRI research, and the use of advanced spectroscopy will provide new insights on mechanisms of action. Hence, this research demonstrates the use of innovative approaches to identify bio-compatible materials for maintaining quality and integrity of biological systems under freezing conditions.

This research will provide transformative experience for graduate students and undergraduate research assistants in their appreciation of how chemistry principles are used in problem-solving. Successful recruitment and training of students with diverse backgrounds will provide an enriching environment in the academic communities within the college and in the local community.

Students’ practice of essential skills of critical thinking, problem solving, teamwork, and leadership will lead to the development of future biomaterial researchers and an highly capable and adaptable workforce.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.