In vitro and in vivo digestibility from bionanocomposite edible films based on native pumpkin flour/plum flour

Abstract

Pumpkin (Cucurbita maxima) flour was used as an unconventional food hydrocolloid source for the development of glycerol-plasticized edible films using the casting methodology. Four film systems were made from thermoplastic pumpkin flour (TPPF) to evaluate the effect of matrix concentration (2.5% and 5%) and the addition of a natural filler (bionanocomposite - ‘huesito’ plum (Spondias purpurea) flour), maintaining the same matrix:plasticizer:nanofiller ratio. A comprehensive study in terms of the structural, thermal, crystalline, physicochemical, microstructural and mechanical properties was carried out here. These properties were related to the results obtained from the digestibility tests of the prepared edible films. This study showed that the increase in the concentration of the constituents of edible films significantly affected their properties, despite maintaining the same ratio of the constituents. A plasticizing effect was observed as a result of the increased concentration of the pumpkin flour matrix. This effect allowed obtaining more hydrophobic and plastic materials, and less digestible. It is worth noting that a new classification of resistant starch (RS) (type 6 RS) can be suggested based on the results obtained or the redefinition of the concept of type 5 RS can also be recommended. As for the effect of the addition of natural nanofiller, at a low concentration of the pumpkin flour matrix, natural nanofiller also caused a plasticizing effect. An anti-plasticizing effect was, however, determined at a high concentration of the pumpkin flour matrix. The addition of natural nanofiller in bionanocomposite films did not cause any significant effect on their digestibility.