Fructose is a simple sugar, a member of the carbohydrate family. It's found especially in fruits and honey. Fructose is known for sweetness 2x more intense than that of glucose. It's beloved by humans and the environment.
Fructose or fruit sugar is a monosaccharide, able to be fermented, or combined with other sugars such as glucose to form sucrose. Its sweetness makes it desirable in many foods and drinks.
Fructose is created through photosynthesis in plants. Plants turn sunlight, water, and carbon dioxide into glucose, the primary energy source. Some glucose converts to fructose with action of the enzyme glucose isomerase.
For plants, fructose has several advantages.
Attracting Pollinators: The sweetness of fructose attracts pollinators such as bees and butterflies. These are indispensable to plant reproduction, as they facilitate transfer of pollen from one flower to another.
Seed Dispersal: Fructose-rich fruits entice animals to consume them. Fruit like mangoes and apples increase fructose content as they ripen, making them more appealing. This encourages animals to consume the fruits and aids in seed dispersal, promoting plant propagation.
Energy: Plants like fruits and root vegetables store fructose as an energy reserve for growth and development. Fructose provides quick energy to organisms. Bees prefer nectar high in fructose, which enables them to quickly replenish energy after foraging.
Fructose is found in glycosides, compounds within the cell sap of fruits and flowers. Glycosides help maintain osmotic balance and can provide energy for developing seeds.
In addition, fructose can be derived from sucrose by enzymatic hydrolysis. In industrial processes, sucrose is broken down into glucose and fructose using the enzyme invertase, the same used by yeasts.
This becomes high-fructose corn syrup (HFCS). The sweetener is used in many processed foods. Australian honey is rich in this sugar naturally, with 36-50% fructose and 28-36% glucose.
Properties of Fructose
Sweetness: Fructose is approximately 1.5 times sweeter than sucrose (table sugar) and 2.5 times sweeter than glucose. This intense sweetness makes it an attractive ingredient in processed foods.
Water Solubility: Fructose is highly soluble in water, allowing it to be easily transported within plants and readily incorporated into various food products. Solubility contributes to its sweetness and makes it easily absorbed by the digestive system.
Hygroscopicity: Fructose readily absorbs moisture from the air, which can contribute to the soft texture of baked goods and candies.
Keto Sugar: Unlike glucose, which is an aldose sugar, fructose is a ketose sugar. This structural difference affects how it's metabolized in the body.
An aldose includes an aldehyde (CHO) group of carbon, hydrogen and oxygen. A ketose has a ketone (CO) group, made of carbon and oxygen.
Fermentable Sugar: Fructose can be fermented by various microorganisms, leading to the production of alcohol and carbon dioxide. This property is used in the brewing and baking industries. Fermenting 200 g fructose can yield 92 g ethanol.
Polysaccharide Partnerships
Sucrose: Fructose combines with glucose to form sucrose, the common table sugar used worldwide.
Inulin: Plants like Jerusalem artichokes, garlic, leeks and chicory root store energy as inulin, a polysaccharide composed of fructose chains. Inulin is a dietary fiber with prebiotic properties. It's a carbohydrate reserve in many plants, especially in roots and tubers.
Levulin: This polysaccharide is produced through the breakdown of fructose and has potential as a source for biofuels.
Microbial Consumption and Fermentation
Fructose is readily digestible by many microbes, both in the human GI tract and the environment. This makes it an important carbon source for many microorganisms.
In humans, fructose is absorbed in the small intestine and metabolized in the liver. Unlike glucose, which can be quickly used by cells, fructose needs specific transport mechanisms and enzymes for metabolism.
In the environment, microbial communities readily use fructose as a carbon source, enhancing carbon cycling in ecosystems. This process promotes soil health and contributes to maintaining the balance of microorganisms vital for plant growth.
Non-Fiction Books:
Fiction Books:
READ: Lora Ley Adventures - Germanic Mythology Fiction Series
READ: Reiker For Hire - Victorian Detective Murder Mysteries