Chemical and mechanical properties of cassava starch bioactive film with jambolan (Syzygium cumini L.) extract addition

Abstract

Jambolan is a fruit found in the north, southeast and northeast of Brazil. The fruit extract has high antioxidant activity, due to the presence of bioactive compounds, such as carotenoids and phenols. The study aimed to elaborate edible films from cassava starch as matrix and addition of jambolan extract. The jambolan aqueous extract was obtained by concentrating process using a rotary evaporator. The assays were carried out according to a 2² full-factorial central composite design with three center point replicates, to assess the effects of glycerol (from 7.95% to 22.05%) and jambolan extract (from 15.9% to 44.1%) concentrations on the mechanical properties (force and deformation at the breaking point) and phenols content of the film. A reduction of the force from 3.61 N to 2.55 N, and increase of puncture deformation from 1.44% to 76.33% were verified with the use of high contents of glycerol and jambolan extract. A statistical analysis of the results showed that the linear and quadratic effects of glycerol and jambolan extract concentrations and their interactions were significant on the force and puncture deformation at a 95% and 80% confidence level, respectively. The effect of jambolan extract concentration was significant on phenols content at a 95% confidence level with coefficient of determination (R²) 0.9782. The interactions between glycerol and jambolan extract facilitated the formation of cassava starch films with good mechanical and bioactive properties.

Keywords:
Packing; Plasticizer; Antioxidant; Phenols; Force; Deformation; Edible