| Summary: | 碩士 === 靜宜大學 === 食品營養學系 === 103 === The objectives of this study were to investigate the changes of starch content and physicochemical properties of banana flours and banana starch in the different ripening stages. Unripe banana were treated with ethylene gas and stored at low temperature (15℃) for seven days during ripening. The changes of total starch, resistant starch, chemical compositions and physicochemical properties were analyzed each day during ripening.
The results showed the total starch and resistant starch content of banana flours in the different ripening stages were 76.2% and 34.6%, respectively at the harvest stage. Both total starch and resistant starch content were significantly declined to 25.3% and 8.8%, respectively with progress of ripening. Free sugar content of banana increased with the increases of ripening stage. Swelling power of banana flour decreased with the increases of ripening stage, but solubility increased. These phenomenon could be the decreases of starch content of banana flour during ripening. Both water insoluble and alcohol insoluble solids of banana flour decreased with the progress of ripening stage. The water-soluble fiber of banana flour increased with the increases of ripening stage. As ripening stage extended, the ranges of gelatinization temperature of banana flours increased. Two endothermic peaks were appeared at the stage 7 that could be the increases of free sugar content in the banana flour during ripening. Gelatinization enthalpy of banana flour decreased with the increases of ripening stage. The similar results of gelatinization characteristics were observed in bananas flour and banana starch. The highest peak viscosity and setback of pasting properties of banana flour were observed in the stage 1 of unripen banana because of high starch content. The scanning electron micrograph of banana starch showed the size of starch granular ranged in 10-50 μm. The shapes banana starch appeared to be round and rectangle on the unripe stage. Broken granular gradually appeared on the surface of banana starch granular with the progress of ripening that could be caused by enzyme reaction during ripening.
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