Magical Additives: Molecular Encapsulation Technology of Cyclodextrin and Its Application in Modern Food

Dairy products are a treasure trove of valuable bioactive substances, and once this is understood, dairy manufacturers have a different perspective on them. Snow Brand Milk Products Co., Ltd. has successfully isolated and refined a type of cyanic acid with anti-infective properties, as well as ganglioside GD₃, and has begun selling them as reagents. Until now, this cyanic acid could only be extracted from the urine of cancer patients, and GD₃ could only be extracted from bovine brain, making it extremely expensive. Dairy products are now recognized as raw materials for functional foods, and the company will continue to invest heavily in research on the bioactive substances in dairy products.

Recently, infant formula made based on these research findings has become closer to breast milk, thanks to various efforts made in this regard. Morinaga Milk Industry launched "lactohepatoflavone," which has anti-infection properties, while Meiji Milk Industry launched products containing "docosahexaenoic acid," which has been shown in animal studies to improve learning abilities. Although research on milk has made progress, the differences between formula and breast milk remain significant. Breast milk contains hundreds of physiologically active substances, and if the concentration of these substances changes as the infant develops, formula must be formulated primarily with a limited number of these substances.

Even if formula milk powder made in this way has some components similar to breast milk, it can never compare to breast milk. Moreover, and most importantly, in most cases, only human substances have effects on humans. Assistant Professor Yuji Takeya of the University of Tokyo's Faculty of Medicine, who studies breast milk from an obstetrics and gynecology perspective, believes that "modern breast milk is the result of millions of years of human evolution; therefore, all substances contained in breast milk should have some physiological significance." Based on research into breast milk, "brain-boosting functional foods" have been developed with added physiologically active substances that promote brain development.

Even inexpensive, low-quality raw materials can be transformed into excellent processed foods with just a small amount of a certain substance, achieving results comparable to high-quality raw materials. This magical additive is cyclodextrin. Dextrin is composed of glucose molecules linked together. Cyclodextrin can also be described as a substance composed of multiple glucose molecules linked in a ring. It consists of 6 to 12 glucose molecules linked in a ring. The outer side of the cyclodextrin molecule has a strong affinity for water, while the inner side is lipophilic.

Therefore, the lipophilic inner ring has the property of encapsulating various molecules or reactive groups, thus stabilizing these encapsulated substances. Cyclodextrin was discovered as early as 90 years ago, but due to the lack of an effective manufacturing method, it was an expensive substance, and its use was limited to very small quantities to make bitter medicines easier to take. Around 1975, Japan discovered a bacterium with an enzyme that produces cyclodextrin. Using this enzyme on starch, cyclodextrin can be mass-produced at a low cost.

Since then, cyclodextrin has been mass-produced and used in food processing. Adding cyclodextrin to food has various functions, including removing odors and stabilizing aroma and color. Especially in the manufacture of sausages and hamburgers, where inexpensive scraps of meat, such as offal, are often added, using cyclodextrin to remove odors makes them virtually indistinguishable from those made with high-quality ingredients. Adding cyclodextrin to old rice eliminates its off-flavors, gives it a slightly sweet taste, and makes it glossy, making it almost indistinguishable from new rice.

Cyclodextrin is also an essential substance in the production of shredded purslane, a vegetable whose spiciness and color are easily lost. Because cyclodextrin is a natural additive and does not need to be labeled, it is generally unknown to the public. In the past two or three years, cyclodextrin has been widely added to many processed foods, including convenience foods. The applications of cyclodextrin in food processing, depending on their purpose, include the following: stabilizing substances that are easily oxidized, substances that can be decomposed under ultraviolet light, and substances that are unstable in water.

It can maintain the stability of fat-soluble vitamins, unsaturated fatty acids, and natural pigments. Adding it to volatile foods such as spices, essential oils, and flavorings can prevent their volatilization. Because it improves solubility, solidification, and hygroscopicity, it enhances the flavor, texture, and color of food. In particular, it improves emulsification and foaming properties, maintaining the fluidity of margarine and oils that make pastries crisp. Using cyclodextrin as a powdered base, only a small amount is needed to maintain flavor, prevent moisture absorption, and prevent the volatilization of aroma components.

In addition, modified cyclodextrins are widely used in the food industry. However, cyclodextrins also have several drawbacks. To overcome these drawbacks, second-generation cyclodextrins have been researched and developed. These second-generation cyclodextrins include methylated and propylated cyclodextrins, as well as cyclodextrins with glucose-linked branches at the α-1,6 positions. Compared to the first generation, second-generation cyclodextrins exhibit improved solubility in water and organic solvents and are more stable to enzymes.