Physico-chemical properties and filmogenic aptitude for edible packaging of Ecuadorian discard green banana flours (Musa acuminanta AAA)

Abstract

Physico-chemical, functional properties, and filmogenic characteristics were determined in pulp (P) and whole (W) banana flours (BF), pretreated or not (preT and unT, respectively) with sodium metabisulfite, obtained from cultivars of Ecuadorian Musaceae: Musa acuminata AAA. The proximal composition revealed a high content of fat, protein, ash, and fiber in whole banana flours, while the total starch and amylose content was greater in pulp flours. The starch granules of both pulp and whole green banana flours presented an elongated and lenticular sizes and shapes, which could be related to the amount and variations in amylose and amylopectin structure in the raw materials. Pretreatment with metabilsulfite favors the increase in L* and b* parameters, while a* is reduced; likewise, the presence of the peel tends to darken the untreated flours. Water absorption, solubility and swelling capacity rose above 70 °C, matching the gelatinization temperature observed by DSC (74–78 °C). The temperature of gelatinization was higher for the pretreated whole banana flour, noticeably, the highest enthalpy ΔHgel (32.23 Jg-1) corresponded to the untreated whole banana flour. All banana flours had the ability to form filmogenic suspensions that showed a similar pseudoplastic behavior regardless of the flour composition, except for the pretreated pulp flour, which showed less shear thinning. The viscosity recovery capacity with the decrease in temperature was almost total in the untreated samples, while in the treated samples was lower (~20%). The higher amount of amylopectin favored the viscoelastic properties in the filmogenic suspension, while the lower content of this compound diminished these properties. For the aforementioned, green banana flours are an ingredient of interest and their ability to form filmogenic solutions can be a good alternative for its subsequent industrial application.