food addtive glucono delta lactone

Traditional tofu is made by coagulating soy milk with gypsum and brine. Now, a better alternative to gypsum and brine called glucono delta-lactone (GDL), has been invented. Tofu coagulated with GDL is more tender, has a higher flavor and nutritional value, and is absolutely harmless to the body. The boxed tofu available in supermarkets is made using GDL coagulation.

Overview

Glucono delta-lactone, abbreviated as GDL, with the molecular formula C6H10O6.It is a white crystalline or powdery substance, almost odorless, with a sweet and sour taste. It is easily soluble in water. Glucono delta-lactone is used as a coagulant, mainly in the production of tofu、cheese, and can also be used as a protein coagulant in dairy products.

Principle

The principle of using glucono delta-lactone to coagulate tofu is that when GDL dissolves in water, it converts into gluconic acid, which has an acid-coagulating effect on the protein in soy milk. Due to the slow decomposition of GDL, the coagulation reaction is uniform and efficient, resulting in pure and delicate tofu with good water drainage, high heat resistance, and a delicious taste. By adding other coagulants such as gypsum, brine, calcium chloride, and flavorings, various flavored tofu can be produced.

 Uses

Tofu Coagulant

Using glucono delta-lactone as a protein coagulant in tofu production results in tofu with a white, tender texture, without the bitter taste associated with traditional brine or gypsum. It prevents protein loss and achieves a high tofu yield while being convenient to use.

Since tofu made solely with GDL may have a slightly acidic taste, which is not desirable for tofu, GDL is often used in combination with CaSO4 or other

coagulants.

According to reports, when producing fresh tofu, a GDL/CaSO4 ratio of 1/3 to 2/3, with an additional amount of 2.5% of the dry soybeans, and a temperature control of 4°C, can result in a tofu yield five times the weight of the dry soybeans, with good quality.

However, using GDL to make tofu has some issues worth noting, such as reduced chewiness and texture compared to traditional tofu, as well as a lower amount of wash water resulting in higher protein loss in the soybean residue.

Dairy Coagulant

GDL is not only used as a protein coagulant in tofu production but also as a coagulant for dairy proteins in the production of yogurt and cheese.

Studies have shown that the gel strength of milk formed by GDL acidification is twice that of the fermented type, while the gel strength of goat acid milk gel produced by GDL acidification is 8-10 times that of the fermented type. They believe that the lower gel strength of fermented yogurt is possibly due to the interference of fermentation agent substances (biomass and polysaccharides) in the gelation of proteins.

Research has also indicated that the gel formed by heating milk with 3% GDL at 30°C has a similar structure to that produced by fermentation with lactic acid bacteria. Furthermore, it has been reported that adding 0.025%-1.5% GDL to buffalo milk achieves the desired curd pH, and the specific amount varies depending on the fat content of buffalo milk and the ripening temperature.

Quality Improver

The use of GDL in luncheon meat and canned pork can enhance the effect of colorants, thereby reducing the dosage of highly toxic nitrites. Additionally, GDL

also has emulsifying, preservative, and gelling properties, which improve the quality of meat-based canned products. The maximum recommended addition of GDL, in this case, is 0.3%. According to reports, adding GDL at 4°C can improve the elasticity of myofibrillar proteins. Whether in the presence of myosin and actin or in the case of myosin alone, the addition of GDL increases the gel strength. Furthermore, mixing GDL (0.01%-0.3%), ascorbic acid (15-70ppm), and sucrose fatty acid esters (0.1%-1.0%) and adding them to the dough can improve the quality of bread. Adding GDL to fried foods can help reduce oil consumption.

Preservative

Studies by Saniea, Marie-Helence, and others have shown that GDL has a significant delaying and inhibitory effect on the production of bacteriophages in lactic acid bacteria, thus ensuring normal growth and reproduction of the bacteria. Adding an appropriate amount of GDL to milk can prevent the instability of cheese products caused by bacteriophages. Qvist, Sven, and others have studied the preservative properties of GDL in large sausages and found that adding 2% lactic acid and 0.25% GDL effectively inhibits the growth of Listeria monocytogenes. Samples of large sausages inoculated with Listeria monocytogenes stored at 10°C for 35 days showed no bacterial growth, while samples without preservatives or with only sodium lactate added showed rapid bacterial growth at the same storage conditions.

However, it is worth noting that excessive use of GDL can cause a noticeable off-flavor in some individuals. According to reports, mixing GDL with sodium acetate in a ratio of 0.7-1.5:1 can extend the shelf life and freshness of bread.

Acidulant

GDL, as an acidulant, can be added to sweet fruit syrups and jellies, such as vanilla essence and chocolate banana. It is the main acidic substance in composite

leavening agents and slowly releases carbon dioxide, resulting in a uniform and delicate bubbles, producing flavorful pastries.

Chelating Agent

GDL, as a chelating agent, is used in the dairy and beer industries to prevent the formation of milk stone and tartar.

Protein Coagulant

In protein-containing industrial wastewater, the addition of a coagulant made from GDL, magnesium salts, and alum can cause protein aggregation and precipitation, which can be removed by physical methods.Glucono delta lactone is a white crystalline powder that can be stored for a long time under dry conditions. However, it is prone to decomposition in humid environments, especially in water solutions. At room temperature, the lactone partially decomposes into acid within 30 minutes in solution. The hydrolysis rate increases at temperatures above 65 degrees, and at temperatures above 95 degrees, it rapidly and completely converts to gluconic acid. Therefore, when using lactone as a coagulant, it should be dissolved in cold water and used within half an hour. Avoid storing the water solution for an extended period.