color-plantsThe colors that we observe in fruits and vegetables are attributed by 4 primary pigments: chlorophylls, carotenoids, anthocyanins, and betalains. Today we will be focusing on chlorophylls. Chlorophylls are green and blue pigments found naturally in the chloroplasts of plants and algae, as well as in photosynthetic cyanobacteria such as spirulina and chlorella. One molecule of chlorophyll contains one molecule of the mineral magnesium, which makes green fruits and vegetables decent sources of magnesium. Notice the long hydrocarbon tail (Fig. 1) of chlorophyll. This chemical feature gives chlorophylls a high solubility in oils and poor solubility in aqueous solutions like water.

One molecule of chlorophyll contains one molecule of the mineral magnesium, which makes green fruits and vegetables decent sources of magnesium. Notice the long hydrocarbon tail (Fig. 1) of chlorophyll. This chemical feature gives chlorophylls a high solubility in oils and poor solubility in aqueous solutions like water.

Veri-Green Canned Green Beans

Veri-Green Canned Green Beans

Chlorophyll is highly unstable in heat, which means that the vibrant green color will turn into an olive to brown color when heated. Imagine making a green bean casserole, your green beans will start off with a nice green color and by the end of the baking process, your green beans are mostly now “brown” beans. Fear not, there is a solution to this problem. Food scientists have found a way to improve the heat stability of chlorophylls by substituting the magnesium ion with either zinc or copper. The zinc ions and copper ions stabilize the entire molecular structure of chlorophyll and provide a much better heat stability compared to its native structure. An example of a food product that utilizes this technique is canned green beans. The green beans are pretreated with zinc chloride before canning and

 

Fear not, there is a solution to this problem. Food scientists have found a way to improve the heat stability of chlorophylls by substituting the magnesium ion with either zinc or copper. The zinc ions and copper ions stabilize the entire molecular structure of chlorophyll and provide a much better heat stability compared to its native structure. An example of a food product that utilizes this technique is canned green beans. The green beans are pretreated with zinc chloride before canning and retorting to preserve the color of green beans.

Author: Ben Yeap, M.S., Coalescence Food Scientist

Tags: ,
0