Do fillers improve the physicochemical properties of antimicrobial tapioca starch edible films?

Abstract

Edible films containing natural antimicrobials, like natamycin and nisin, constitute an emerging technology that provides an additional stress factor for food preservation. However, it has been observed that edible films based only on tapioca starch present several failures, such as poor mechanical properties and low hydrophobicity. Pumpkin and oat bran are ingredients that provide multiple health benefits. In this work, it was intended to improve mechanical properties and hydrophobicity of tapioca starch edible films, containing natamycin and nisin, by the addition of pumpkin peel, pumpkin mesocarp or oat bran fillers. In turn, the effect of fillers on the films was evaluated through the evaluation of their color, water vapor permeability, morphological characteristics, and microbiological behavior. Results showed that pumpkin fillers improved mechanical properties, reducing the strain at break and increasing the stress at break of tapioca starch edible films. Particularly, pumpkin peel filler increased 36 times the firmness of tapioca starch films, reaching a value of 87.64 MPa. Also, this filler increased 300% the hydrophobicity of the films with a contact angle of 48.29°. The incorporation of all studied fillers allowed the normal diffusion of natamycin. However, the different fillers retained the nisin in different degrees and, particularly, oat bran filler was the one with the highest affinity for it. After evaluating all the studied properties, it can be concluded that the composite film filled with pumpkin peel, is an improved version to the one without it, for food packaging.

Effect of Wheat and Oat Bran on the Physicochemical Properties of Edible Starch‐Based Films Obtained by Extrusion for Food Packaging Applications

“…Similar behavior was observed by Ollé Resa et al. [ 31 ] using 1.5 wt% of OB in casting starch‐based films. On the other hand, the combination of unprocessed grains and some holes presented in the films containing the lowest concentration of bran, as morphological study shown (Figure 2B,D), could lead to the non‐modification of σ – ɛ curves behavior.…”

“…Ollé Resa et al. [ 31 ] agreed and reported the same behavior in cassava starch films containing OB prepared by casting.…”

“…Oat bran has been widely used in the diet of consumers, since it is a rich source of unsaturated fatty acids, phenolic acids, and oat alkaloids, among other components. [ 28–31 ] Cassava starch films with 1.5 wt% oat bran obtained by casting showed decreases in the water resistance and no‐significant differences in the uniaxial stress parameters. [ 31 ]…”

“…[ 28–31 ] Cassava starch films with 1.5 wt% oat bran obtained by casting showed decreases in the water resistance and no‐significant differences in the uniaxial stress parameters. [ 31 ]…”

“…Oat bran has been widely used in the diet of consumers, since it is a rich source of unsaturated fatty acids, phenolic acids, and oat alkaloids, among other components. [28][29][30][31] Cassava starch films with 1.5 wt% oat bran obtained by casting showed decreases in the water resistance and no-significant differences in the uniaxial stress parameters. [31] The employ of a scalable manufacturing process to obtain biodegradable materials is currently a desire of the scientific community, and has aroused the interest of the plastics industry since it could have new "eco-friendly" products without the need for costly investments.…”