Trehalose is a natural sugar known for its protective abilities. This disaccharide stabilizes biological materials under challenging conditions, playing an important role in the survival and adaptation of various life forms.
Understanding Trehalose
Trehalose is a disaccharide formed from two alpha-glucose units, linked by a unique alpha,alpha-1,1-glycosidic bond. This structure gives trehalose distinct properties compared to sucrose, which combines glucose and fructose.
Unlike sucrose, trehalose is a non-reducing sugar because its specific bond keeps its end groups in a closed-ring form. This makes trehalose resistant to acid hydrolysis and stable in solutions, even at high temperatures or under acidic conditions. Though both share the chemical formula C12H22O11, their different arrangements result in varied physical and chemical behaviors.
Where Trehalose Naturally Occurs
Trehalose is widely distributed in nature, found across various organisms. It is synthesized by bacteria, fungi, insects, invertebrates, and both lower and higher plants. In many of these organisms, trehalose serves as an energy source and provides protection against environmental stresses.
Mushrooms, yeast, and certain plants, such as the “resurrection plant” (Selaginella), contain trehalose. Insects like grasshoppers, butterflies, and bees use trehalose as their primary blood sugar, similar to glucose in humans, and as an energy storage molecule for activities like flight. In fungi, trehalose acts as a reserve carbohydrate and a stress metabolite, accumulating in resting cells and spores, sometimes making up a significant portion of their dry weight.
Remarkable Properties of Trehalose
Trehalose protects biological molecules from environmental stresses. It stabilizes proteins and cell membranes, preventing protein denaturation and aggregation caused by desiccation, freezing, or heat.
It achieves this by replacing water molecules around proteins and membranes, forming hydrogen bonds that maintain their three-dimensional structure. This mechanism, known as “anhydrobiosis,” allows organisms to survive prolonged periods without water. Trehalose forms a glassy matrix that physically supports cellular components, preventing ice crystal damage during freezing (cryoprotection) and maintaining integrity during drying. It also interacts with plasma membrane phospholipids, protecting lipid bilayers from intracellular ice damage.
Diverse Applications of Trehalose
Trehalose’s properties have led to its widespread application across industries. In the food industry, it functions as a sweetener, stabilizer, and preservative. It is used in frozen foods like ice cream to lower the freezing point, and in baked goods and instant noodles to extend shelf life and maintain texture. Trehalose can also enhance flavors, mask bitter tastes, and improve the creamy feel in various products.
In pharmaceuticals, trehalose stabilizes sensitive biological materials like vaccines, antibodies, and therapeutic proteins during storage and transport. It maintains their activity and structure, especially in freeze-dried formulations. It also finds use in medical research for cryopreservation of cells, tissues, and organs, including sperm and stem cells, protecting them from freezing damage. The cosmetic industry incorporates trehalose for its moisturizing and antioxidant properties. It helps skin retain moisture, mimics natural hydration factors, and protects against oxidative stress and environmental damage.
Trehalose and Human Health
When consumed, trehalose is broken down into two glucose molecules by the enzyme trehalase. This enzyme is found primarily in the small intestine’s brush border, but also in the kidney, liver, and blood plasma. The glucose released from trehalose is then absorbed and metabolized by the body.
Trehalose is a nutritive sweetener, providing 4 kilocalories per gram, with approximately 45% of sucrose’s sweetness. It has been evaluated for safety by food regulatory authorities and is generally recognized as safe for human consumption. While most people digest trehalose without issue, a small percentage of individuals may have trehalase deficiency, which can lead to digestive discomfort like diarrhea if they consume large amounts of trehalose-rich foods such as mushrooms.