EFFECT OF DIFFERENT THERMAL TREATMENTS AND STORAGE ON STARCH DIGESTIBILITY AND PHYSICOCHEMICAL CHARACTERISTICS OF UNRIPE BANANA FLOUR

摘要

Unripe banana flour is an important source of indigestible carbohydrates, mainlynresistant starch (RS). However, during cooking of the fruit, the indigestible carbohydratesnare transformed to digestible. The aim of this study was to test differentntreatments: cooking (5, 15 and 25 min), cooking plus high-moisture treatmentn(HMT) and cooking plus HMT plus storage (HMT + S), to increase the slowlyndigestible starch (SDS) and RS fractions. Polarization light microscopy, leachednamylose, X-ray diffraction pattern, thermal and pasting characteristics, and starchndigestibility analysis of the flours were evaluated. The longest cooking timendecreased the RS content in the non-gelatinized samples; HMT and HMT + Snincreased the SDS level. These samples could be used in products without heatntreatment during their preparation. The gelatinized samples presented a significantnfraction of RS in comparison with the non-gelatinized, demonstrated that thensamples can be used in products where cooking is necessary, conserving a highnamount of indigestible carbohydrates.