Description

Cyclodextrins are cyclic α-(1,4)-linked maltooligosaccharides. α-, β-, and γ-Cyclodextrin consist of 6, 7, and 8 glucose units, respectively.

In foods, cyclodextrins can protect volatile compounds from evaporation, and chemically sensitive products from oxidation or photodegradation. Cyclodextrins also can stabilize emulsions and foams, mask certain undesirable tastes and odors, provide bulk, and improve texture. The suitability of the different cyclodextrins for these applications varies on the size of the "guest" molecule which the cyclodextrin ring should accommodate. With its larger ring size, γ-Cyclodextrin (γ-CD) has wider applications in this respect than α- or β-CD[1].

γ-CD production

In the first step of γ-CD production, food-grade, liquified starch is treated with CGTase under controlled pH and temperature conditions[2]. Cyclohexadecen-1-one (CHDC) or another appropriate complexant is added to precipitate formed γ-CD. The complex is removed and purified. The complexant is separated from γ-CD by extraction with n-decane, a component of "odorless" light petroleum hydrocarbons that may be used in some food processes. According to the specifications of γ-CD, total residue levels of volatile organic compounds (i.e., CHDC and n-decane) will not exceed 20 ppm. γ-CD is obtained by crystallization as a white powder with a purity of P98% (on a dry matter basis).

Uses of γ-CD in food

The ability to form complexes with a wide variety of organic molecules coupled with a relatively high water solubility makes γ-CD a versatile food ingredient. It may be used as a carrier and stabilizer for flavors, typically in a ratio of about 5–20 parts of flavor with 100 parts of γ-CD. By forming inclusion compounds, γ-CD also can stabilize certain sensitive colors (e.g., lycopene and anthocyanin), fat-soluble vitamins, and polyunsaturated fatty acids (PUFAs). γ-CD-stabilized preparations of vitamins and PUFAs are useful for the formulation of dietary supplements and meal replacements (formula diets) in powder form. γ-CD can stabilize emulsions of fats and oils. This property is useful for the preparation of bread spreads in which the typical use levels of γ-CD would not exceed 20%. In frozen dairy desserts, γ-CD improves the melting behavior at a concentration of less than 3%. In ready-to-eat dairy desserts, or desserts prepared from dry mixes with the admixture of milk (e.g., chocolate mousse), γ-CD stabilizes the fat/water emulsion and the foam, also at levels up to 3%. The addition of about 1–2% γ-CD to dough increases the volume of baked products. In no-fat or low-fat doughs, an admixture of 1% γ-CD is sufficient to achieve this effect[3].

Toxicity

On oral administration, no deaths occurred at γ-CD levels of up to 16 g/kg bw in mice and 8 g/kg bw in rats. Intraperitoneal and subcutaneous administration of γ-CD did also not produce any immediate or delayed adverse effects. However, when γ-CD was administered intravenously to mice (5, 7.5, or 10 g/kg bw) and rats (2.5, 3.75, or 5 g/kg bw), some dose-related signs of toxicity, such as piloerection and sluggishness, were observed within 1 h to a few days after treatment in all dose groups. In both mice and rats, some deaths occurred within a few days (1/10, 4/10, and 5/10 mice, and 0/10, 4/10, and 6/10 rats in the low-, mid-, and high-dose groups, respectively). The surviving animals recovered and appeared healthy at the end of the 14-day observation period. Macroscopic examination of the animals did not reveal any treatment-related gross alterations.

References

[1] Mielcarek, J. “Analytical study of photodegradation of inclusion complexes of nimodipine with alpha-, gamma-cyclodextrin, methyl-beta-cyclodextrin, and hydroxypropyl-beta-Cyclodextrin.” Drug Development and Industrial Pharmacy 24 2 (1998): 197–200.

[2] Hao Wu . “Improved production of gamma-cyclodextrin from high-concentrated starch using enzyme pretreatment under swelling condition.” Carbohydrate Polymers 284 (2022): Article 119124.

[3] I.C Munro . “Safety assessment of γ-cyclodextrin.” Regulatory Toxicology and Pharmacology 39 (2004): Pages 3-13.