Scientists Developed Ultra-Thin Heteroprotein Films to Expand Their Applications in Food Packaging Industries

Scientists have created ultra-thin heteroprotein films with excellent thermal, mechanical, and pH stability, which could pave the way for more thin film applications in the biomedical and food packaging industries. These films are much thinner than other protein or plastic films. They are soft and thin, with the added benefit of being more flexible than other films.

Several modifications of these protein films using appropriate heteroprotein complexes have recently been reported by various research groups. These complexes were typically formed from bulk solutions.

A research team from the Institute of Advanced Study in Science and Technology (IASST), Guwahati, an autonomous institute under the Department of Science and Technology, has successfully developed ultrathin monolayer protein films made of two globular proteins: bovine serum albumin (BSA) and lysozyme (Lys). They used the Langmuir-Blodgett (LB) technique, which results in film thicknesses in the nanometer range.

Dr. Sarathi Kundu, Associate Professor, along with Mr. Raktim J. Sarmah, SRF, a Ph.D. student, developed the first monolayer heteroprotein film using this technique. They investigated the various structures and morphologies of this complex film at various pH levels in order to investigate its stability and related properties.

The two proteins formed a complex at a specific pH of 9.2 as a result of electrostatic attraction and hydrophobic interactions. This monolayer complex was formed at the air-water interface and was later transferred to silicon substrates for further study at a surface pressure of 18 mN/m.

It was demonstrated that the monolayers at the air-water interface can retain their intrinsic structure for an extended period of time due to complexation, resulting in a highly stable film.

Films of such BSA and Lys protein complexes may be useful for fabricating highly stable biodegradable thin films of various protein complexes in order to broaden their applications in thin-film technology.

Various physicochemical methods, such as parameter modification or incorporation of different fatty acids or polyol moieties (glycerol, starch, gelatin, etc.) into this protein complex, can make the film self-supporting for a variety of applications. This study was recently published in the prestigious journal Food Hydrocolloids by the reputable Elsevier publishers.