ABSTRACT
An unripe banana fruit is always perceived as hard, green, sour, mealy (starchy), and odorless. Ÿis status ends when ethylene is produced. Ethylene is a simple hydrocarbon gas (H2C ═ CH2) that causes developmental changes resulting in fruit ripening. Ethylene apparently “turns on” the genes that are then transcribed and translated to make new enzymes. Ÿe enzymes then catalyze reactions to alter the characteristics of the fruit. Ÿese include hydrolases to help break down chemicals inside the fruits, amylases to accelerate hydrolysis of starch into sugar, and pectinases to catalyze degradation of pectin. During this process, chlorophyll is broken down, and sometimes new
8.1 Introduction 71 8.2 Experimental Conditions 72 8.3 Results 73
8.3.1 Uncertainty of the Spectral Measurement 74 8.3.2 Uncertainty of the Digital Image Method 75 8.3.3 Comparing the Digital Imaging and Spectrophotometer
Methods 76 8.3.4 Banana Color Changes with Time 76
8.4 Conclusions and Discussions 77 References 77
pigments are synthesized so that the fruit skin changes color from green to red, yellow, or blue. Acids are broken down so that the fruit changes from sour to neutral. Ÿe degradation of starch by amylase produces sugar which reduces the mealy (¨oury) quality and increases juiciness by osmosis. Ÿe breakdown of pectin between the fruit cells unglues them, so they can slip past each other, resulting in a soÀer fruit. Also, enzymes break down large organic molecules into smaller ones that can be volatile, and this gives an aroma sensation.
