Physicochemical, structural, mechanical and antioxidant properties of zein films incorporated with no-ultrafiltered and ultrafiltered betalains extract from the beetroot (Beta vulgaris) bagasse with potential application as active food packaging

The development of active food packaging based on natural polymers and pigments is of interest to the food industry. Pigments to make this type of packaging can be extracted from waste and by-products, giving added value and reducing production costs. Therefore, the objective of this work was to study the physicochemical, structural, mechanical and antioxidant properties of zein films with non-ultrafiltered (Z-NUBE for films or NUBE for extract) and ultrafiltered betalain extract (Z-UBE for films and UBE for extract) from beet bagasse as active food packaging. SEM analysis showed that the films with Z-UBE showed a more uniform and smoother surface compared to Z-NUBE. FTIR analysis showed that the possible interaction of zein with betalains was due to physical forces, mains by hydrogen bonds. TGA analysis showed that the average degradation temperature for all films was around 313 degrees C, giving a greater weight loss due to the interaction between zein and betalains. Analysis by contact angle determined that films with Z-UBE were the most hydrophobic that films with Z-NUBE. Also, as the concentration of betalains increases, their hydrophobicity increases. Regarding antioxidant properties, ZNUBE showed better antioxidant activity than films with NUBE, mainly by the FRAP method, Z-NUBE1 and ZUBE1 (both with 1% extract) were 251.161 +/- 16.45 and 523.49 +/- 26.04 mu M T/g, respectively. For the phytochemical content, Z-UBE showed a higher amount of betalains (specifically betacyanins) with increasing concentration between 56.05 and 76.43%, but similar content of phenolic compounds, less than 0.1 mEq GA/g. Therefore, it is concluded that the addition of UBE to zein films has a potential application in the food industry as active food packaging in refrigerated meats and products stored at room temperature.

Automated summary

This study investigated the influence of betalain extract from beet bagasse on the physicochemical, structural, mechanical, and antioxidant properties of zein films. The results showed that the addition of betalain extract improved the uniformity and smoothness of the film surface, increased the degradation temperature, and enhanced hydrophobicity. Furthermore, the betalain extract exhibited good antioxidant activity. Therefore, incorporating betalain extract into zein films has potential applications in the food industry as active food packaging.