The smell of ripened mangoes is very strong. Why the smell is so strong. Let’s start some properties of fruit ripening.
The fruit ripening signal is the sudden production of ethylene. Ethylene is the simple hydrocarbon gas produced in ripening fruit and released into the atmosphere. This ethylene signal causes developmental changes that result in fruit ripening. These developmental changes are triggered by the set of enzymes called hydrolases.
Ethylene apparently ‘ turns on’ the genes that are transcribed and translated to make these enzymes. The enzymes then catalyze reactions to alter the characteristics of the fruit. The action of the enzymes causes the ripening responses. Chlorophyll is broken down and sometimes new pigments are made so that the fruit skin changes colour to red, yellow, or blue. Acids are broken down so that the fruit changes from sour to neutral.
The starch is digested by Amylase to produce the simple sweet sugars. As a result, the mealy quality is reduced and juiciness is increased. Finally, enzymes break down large organic molecules into smaller ones that can be volatile, which we can detect as an aroma. A wide range of such compounds has been identified, including esters, lactones, mono – and sesquiterpenes.
Monoterpene hydrocarbons such as cis- ocimene, alpha and beta-pinene, myrcene and limonene seem to be particularly important contributors to the flavour of the fresh fruit, depending upon the variety. The monoterpene cis-ocimene is a major flavour component in mango cultivars Alphonso from India and Jaffna from Srilanka, Among the sesquiterpenes, beta-caryophyllene and alpha – humulene are common components in the volatiles mixture of almost all cultivars of mango.
The mango fruits are harvested in any one of the three stages namely mature green stage in which the fruits have pale ash green colour with smoky appearance, half-ripe stage and ripe stage.
The pulp of ripe fruit harvested at this stage exhibited higher total amounts of the aroma volatiles namely the monoterpenes and the sesquiterpenes. Fruit harvested at the fully ripe stage resulted in higher concentrations of esters, alkanes and norisoprenoids. To achieve better quality and greater aroma volatile production of the ripe fruit, mango should be harvested at the green stage.