Impact of maturity stages and modification processes on resistant starch and starch properties of green banana flour and its glycaemic response.

Abstract

Global demand for functional food ingredients has driven interest in green banana flour modification. This study evaluated the influence of ultrasound (US), blast freezing (BF), clove oil (CO) treatments and dual modification (DM) and chemicals on immature (70 %) and mature (100 %) green banana flour to enhance the functional attributes. Morphological analysis showed BF and US altered starch granular structure of flour and reduced particle size. Structural studies revealed OH stretching vibrations near 3400 cm-1, characteristic of starch, differing between mature and immature modified flour. B-type crystalline peaks were observed with CO and enhanced crystallinity in both the maturity stages. Application of BF displayed reduction in shear stress whereas the use of KMS + CA showed more shear-thinning behaviour. Water solubility index ranged from 6.66 g/g (CO) to 7.9 g/g (US) for immature flour, and 9.31 g/g to 11.74 g/g for mature flour. Hardness was highest with CO (251.61 and 245.34) and lowest with US (168.91 and 179.53). The resistant starch content of mature fruit flour decreased in following order: MUS (41.67) > MBF (33.07 %) > MDM (31.86 %) > MKC (30.7 %) > MCO (27.72 %). The findings provide opportunity to utilize immature and export reject banana to produce nutrition rich products to meet consumer demands for healthy foods.