Yes, a blue apple!

It’s not an apple variety but an innovative solution for lowering post-harvest losses.

Fruits and vegetables, as we all know, are perishable foods that cannot be stored for extended periods of time due to deterioration. In order to coordinate uniform ripening, they naturally release ethylene during respiration as a communication mechanism. The presence of ethylene gas accelerates ripening, hastening deterioration and resulting in massive post-harvest losses.

In order to prevent/reduce these losses, two friends, Timmy Chou and Eric M. Johnson, founded The Bluapple Company and innovated the Bluapple device.

It is a plastic device that contains a refill packet of ethylene absorbers and is intended to properly absorb ethylene gas for up to 3 months, depending on the type of food. When the internal contents of these refills have reached their maximum capacity for absorbing ethylene, we should empty them and utilise them as fertiliser in the plants. The active element does not “fade away,” but instead continues to absorb ethylene until its capacity is achieved.

These refills are sold separately, allowing Bluapples to be reused rather than ending up in landfills. These adorable tiny apples, on the other hand, may be preserved on the countertop of fresh produce, in the refrigerator, or in the dry storage room for a long period (where potatoes and onions are kept).


Another Bluapple gadget, Carbon Bluapple uses the same technology as Classic Bluapple, with the added benefit of reducing odours and contaminants inside the refrigerator. Indeed, the organization offers a low-cost and dependable method of reducing food waste at the household level. Diverse important investigations are being conducted in this era of technological progress for the design of such extraordinary devices employing various technologies.

The science behind Bluapple:

Ethylene gas is released by fruits and vegetables as a natural signalling mechanism to coordinate uniform ripening. The presence of ethylene gas, once condensed in your refrigerator or other storage rooms, continues to speed up ripening and increase deterioration.

In a regular household refrigerator produce bin or storage container, the Bluapple is designed to produce adequate ethylene gas absorption for three months. The active element does not “fade off,” but instead continues to absorb ethylene till its capacity has been achieved. A Year Refill Kit completes the Bluapple ethylene gas control product line, allowing users to reuse Bluapples rather than throwing them away.


Living plants naturally generate ethylene gas as a ripening indication. In reality, when food travelling for the US leaves other nations, industrial-sized gas absorbers are utilised to delay the produce from ripening until it reaches the grocery store. When the fruit was cheap, no one cared, but it is no longer cheap, that’s where blue apples come in.

Blue Apple is one of the three required pillars for produce freshness, humidity control, temperature, and ethylene gas management. These adorable tiny apples contain a package of volcanic material and the oxidizing chemical sodium permanganate. The active component absorbs the gas and renders it inert.

How Ethylene Gas Absorption Works:

The ethylene gas molecule is extremely reactive, and it can easily be oxidised into a non-damaging state. The oxidation of ethylene gas with sodium permanganate is one of the simplest and safest ways to eliminate it from produce storage areas. When ethylene gas reacts with sodium permanganate, the ethylene gas is oxidised, reducing the amount of sodium permanganate available. In most household refrigerators and dry storage areas, the amount of sodium permanganate available will last at least three months.

After three months, BluApple’s refill packet should be replaced with a new one. BluApple’s manufacturers recommend that customers recycle used zeolite by sprinkling it on plants and flowers around the house. Zeolite is a natural soil that contains MnO2, which supplies trace minerals to the soil and makes it an ideal fertiliser.

The carrier media for sodium permanganate (NaMnO4) varies, but a natural zeolite is utilized for the home market. A zeolite is a pure form of ancient volcanic ash with a large crystalline surface area, which makes it a suitable substrate for the oxidation of ethylene gas. When the humidity is too high, the large surface area retains molecules and absorbs water, releasing it back into the atmosphere when it becomes too dry. Of course, the zeolite in the BluApple achieves these goals as well, but its primary role is to eliminate ethylene gas from the produce bin.

Here’s how it works chemically:

3CH2CH2 + 2NaMnO4 + H2O = 2MnO2 + 3CH3CHO + 2NaOH

3CH3CHO + 2NaMnO4 + H2O = 3CH3COOH + 2MnO2 + 2NaOH

3CH3COOH + 8NaMnO4 = 6CO2 + 8MnO2 + 8NaOH + 2H2O

When you put the first 3 equations together, you get:

3CH2CH2 + 12NaMnO4 = 12MnO2 + 12NaOH + 6CO2

Many of the intermediate products generated become irreversibly linked to the media or act as reactants themselves, even if the reaction does not go all the way to the carbon dioxide-producing stage. The sodium hydroxide (NaOH) generated in equations 1 and 2 is an example of this. Through a simple acid-base neutralisation reaction, the NaOH reacts with the acetic acid generated in equation 2 to give the sodium acetate salt (NaCOOCH3). This is depicted below.


When you combine equations 1, 2, and 5, you get:

3CH2CH2 + 4NaMnO4 = 3NaCOOCH3 + 4MnO2 + NaOH + H2O

Read our latest article on: Significance of Plant-Based Functional Foods and Phytochemicals



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