Nopal cladode as a novel reinforcing and antioxidant agent for starch-based films: A comparison with lignin and propolis extract

The potential use of nopal cladode flour (NC) as reinforcing/bioactive agent in cassava starch-based films was evaluated and compared with the use of propolis extract or lignin, which are commonly used for these purposes. Cassava starch-based films containing untreated NC (S-NC), NC treated at pH 12 (S-NC12), aqueous propolis extract at two different concentrations (S-P1 or S-P2), or lignin (S-L) were produced by the casting technique; glycerol was used as plasticizer. NC12 and NC affected the mechanical properties of the cassava starch-based film similarly as compared to propolis extract and lignin. Moreover, NC and NC12 had different performance as reinforcing and antioxidant agent in cassava starch-based film. Thus, S-NC12 film was more elongable (28.5 +/- 6.5%), more hydrophobic (contact angle: 70.8 degrees +/- 0.1), less permeable to water vapor (0.8 +/- 0.0 x 10(-10) g.m(-1).s(-1).Pa-1) and had better antioxidant activity by ABTS(center dot+) (44.70 +/- 0.3 mu M Trolox.g(-1) of film) than the S-NC film. SEM and TGA analysis of films showed that NC12 was better incorporated into the cassava starch matrix than NC, lignin and propolis extract. Overall, nopal cladode flour has potential use in the production of active biodegradable packaging for the food preservation with high oxidation rate. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The potential use of nopal cladode flour as reinforcing/bioactive agent in cassava starch-based films was evaluated, with NC12 and NC showing similar effects on the mechanical properties of the films but differing in their performance as reinforcing and antioxidant agents. NC12 exhibited superior qualities in terms of elongation, hydrophobicity, water vapor permeability, and antioxidant activity, making it a promising option for active biodegradable packaging for food preservation with high oxidation rate.