What makes ethylene gas

However, once fruits are ripe, they tend to spoil quickly, as you might have noticed in your own experience. This article provides an insight into two of the changes that are associated with fruit ripening: 1 softness; and 2 flavor, in particular, sweetness, and the role of ethylene gas in controlling fruit ripening. As fruit-bearing plants grow, the fruits accumulate water and nutrients from the plant and they use these nutrients to create their flesh and seeds.

Most growing fruits initially provide protection to the developing seeds. At this stage, fruits are generally hard and unattractive to predators—including us! After seed development and fruit growth, the properties of the fruit change to make the fruit more attractive to potential consumers, such as animals, birds, and humans [ 1 ].

These changes include the most common ways by which we judge whether a fruit is ripe or not, including external features, such as softness to the touch, and internal features, such as sweetness. Fruits also change color as they ripen. This happens because of the breakdown of a green pigment called chlorophyll, along with the creation and accumulation of other pigments responsible for red, purple, or blue hues anthocyanin , or bright red, yellow, and orange hues carotenoids , to name a few.

First, how is fruit softness regulated? The softness or firmness of a fruit is determined by the state of its cell walls. The three main polysaccharide of the cell wall are cellulose , hemicellulose and pectin. Cellulose is made up of hundreds of glucose sugars joined together to form a long chaiin; hemicelluloses are also long chains of sugars, but unlike cellulose, these can include many different types of sugar, such as glucose, xylose, galactose, and mannose and instead of being linear are branched structures; pectins are also long branched chains of sugars, but in this case the sugars are galacturonic acid, rhamnose, galactose, and arabinose.

As the cell wall begins to break down, the fruit starts to get softer [ 2 ]. Cell wall breakdown happens when proteins called enzymes dissolve these important cell wall polysaccharides.

The activity of these enzymes is directly linked to the shelf life and texture of the fruit [ 2 ]. Fruit softness is also affected by the fluid pressure inside the plasma membrane called turgor pressure. Turgor pressure keeps the fruit firm, just like air pressure inside a balloon keeps the balloon firm. After maturation or harvest, fruits lose fluid water , causing a decrease in turgor pressure, so the fruits shrivel.

During ripening, there is an increase in the breakdown of starch inside the fruit, and a corresponding increase in the amount of simple sugars which taste sweet, such as sucrose, glucose, and fructose. This process is particularly obvious in bananas as they ripen.

Green bananas do not taste sweet at all, and the riper they get, the sweeter they taste. There is also a decrease in acidity as the fruit ripens and a decrease in bitter plant substances, such as alkaloids. Cell Respiration Experiments. Enzyme Activity in Apples. List of Flammable Gases. Science Fair Project on Ripening Bananas. Fastest Growing Plants for a Science Project. Science Projects on Smoking. Fruit Themed Science Activities.

How Do Stomata Work in Photosynthesis? How to Stop the Smog. Measurable Science Fair Ideas. It is a similar principle to using lemon juice to keep fruit fresh, as the enzyme doesn't respond well to acidic conditions.

The company also tested different varieties of banana to find the one which aged the slowest, discovering Cavendish bananas were the best of the bunch.

Now, you can find chopped banana in their fruit pots - all thanks to science. For a longer life 'eat a-day'. Why tomato is the world's favoured fruit. Ocado trials fruit-picking robot.

Apples are ethylene producers while cauliflower is ethylene sensitive. Presence of ethylene in amounts ranging from a few parts per billion ppb to a few parts per million ppm can reduce plant vigour, decrease life of various plant parts and reduce stock quality. Any closed environment, such as truck trailer, shipping container, warehouses and cold rooms, will have a similar effect resulting in increased concentration of Ethylene.

At the latter part of post-harvest, artificial ripening by using ethylene is general practice as it ensures that the produce reaches the consumers retail outlets with a degree of ripeness, which brings out its best in terms of taste, color, texture and nutritional value.

However these conventional methods adopted by most warehouses and cold stores of lowering the temperature and humidity and using gases like nitrogen and sulphur increase the shelf life but have several disadvantages. Refrigeration and humidity control slows decay but is not enough to halt the production of ethylene gas in cold stores and warehouse.

Even small amount of ethylene gas during storage is enough to hasten the process of decay of fresh produce. Controlled Atmosphere Storage CA — The concept of controlled atmosphere CA storage of horticultural products is based on the control of two major factors affecting plant aging.

Controlling ethylene gas will maintain the quality and extend the life of horticultural products, allowing them to be stored for a much longer period of time. While refrigeration and humidity control will slow ripening and decay, they will not halt ethylene control.

However it is necessary to ensure the following:.