A quick FT-IR method for estimation of α-amylase resistant starch from banana flour and the breadmaking process

Abstract

Humankind is striving to adopt a nutrient-rich healthy diet leading to holistic development, and the fundamental limitation is the need for more awareness of alternative resources. For a decade, resistant starch (RS) has been gaining attention for its health-boosting impacts. Also, only a few methods are reported for quantifying resistant starch in food items; that, too, is a decade old. The present research aims at two objectives. First, to develop an accurate method for precise measurement of green banana RS in lower quantities, as the current AOAC method can only detect RS if its concentrations are higher than 2% in the sample. The second is to study its practical implication by measuring the RS from unripe banana flour and banana bread. To this end, we have developed a quick Fourier Transform-Infrared (FT-IR) spectroscopy-based method for quantifying RS using just one milligram of a sample, giving results in ten minutes. The quantification range for the presented method is 1–7 mg g−1 of sample. We also observed remarkable consistent changes in absorption intensity at 1641 cm−1 with increasing RS concentrations in the statistically supervised study. The absorbance at wavenumber 1641 cm−1 appeared in all the amylase-treated starch samples and was remarkably absent in Glucose and Maltose; This region was therefore considered RS’s fingerprint. Moreover, the absorbance quotient of 1641/2930 was significant for quantifying crystallinity in RS. Also, we investigated the assay procedure’s compatibility to quantify RS in food during the banana breadmaking process. The results are further validated with AOAC 2002.02.