Effects of multiple-step cold plasma processing on banana (Musa sapientum) starch-based films

In recent years, films of biodegradable materials have been studied to determine and improve their physical properties, mechanical strength, and hydrophobicity. This research focused on the study of banana starch-based films (Musa sapientum). The films were prepared using the casting method, and a 2k experimental design was conducted to evaluate the effects of cold plasma treatment on three steps of film production. Dielectric barrier discharge (DBD) plasma (excitation frequency of 400 Hz, voltage of 20 kV, and 15 min of processing time) was applied in three processing phases: on the starch granules, the filmogenic suspension, and the film. Plasma-treated films presented better short-range order structure degree (or crystalline/amorphous ratio) than untreated films. Significant differences were observed on the surface of the films, especially when the filmogenic suspension or the film were subjected to plasma treatment. Films produced with the treated starch granules and filmogenic suspension presented the lowest values of moisture (<9.5%) and solubility (<31.1%), while the films produced with DBD plasma-treated starch granules and also subjected to plasma treatment presented the highest water contact angle (65.1 degrees), the highest tensile strength (9.11 MPa), and good puncture resistance (0.33 MPa), resulting in the highest hydrophobicity and highest mechanical strength among the tested films. Research must be done to adapt these promising results and apply to other techniques and botanical sources.

Automated summary

In recent years, research has been conducted on films made from biodegradable materials to improve their physical properties, mechanical strength, and hydrophobicity. This study specifically focused on banana starch-based films and their production process using cold plasma treatment. The results showed that plasma-treated films had better crystalline/amorphous ratio and improved surface properties compared to untreated films. Films produced with treated starch granules and filmogenic suspension had the lowest moisture and solubility values, while films produced with plasma-treated starch granules and subjected to plasma treatment had the highest water contact angle, tensile strength, and puncture resistance, making them the most hydrophobic and mechanically strong among the tested films.