Sorbitol:  properties, uses, pros, cons, safety

Sorbitol is a chemical compound, a six-carbon-atom sugar alcohol obtained chemically from purified glucose by hydrogenation. In the human body, it oxidises to fructose after consumption, but it does not affect blood sugar or uric sugar and can therefore be used as a sweetener for diabetics.

Due to its chemical structure, sorbitol is less caloric compared to sucrose and has a minimal impact on blood sugar levels, making it useful in products intended for people with diabetes or those seeking low-calorie alternatives.

Description of Raw Materials

Sorbitol is a polyol (sugar alcohol) commonly used as a sweetener and humectant in many food, pharmaceutical, and cosmetic products. The main raw materials for its production are:

Glucose: Derived mainly from corn starch, glucose is the starting point for sorbitol synthesis. It is a monosaccharide that serves as the base molecule for the reduction reaction.

Hydrogen: Used in the hydrogenation process, hydrogen reacts with glucose to form sorbitol.

Industrial Chemical Synthesis

• Preparation: The mixture is prepared by dissolving glucose in water. This aqueous glucose solution is then ready for hydrogenation.
• Hydrogenation: The glucose solution is exposed to hydrogen in the presence of a catalyst, typically nickel. This process occurs under high pressure and temperature conditions.
• Cooling and Separation: After hydrogenation, the mixture is cooled. Sorbitol separates from the solution as a viscous liquid.
• Purification: The sorbitol solution is purified to remove the catalyst and other impurities. This can include filtration and crystallization.
• Concentration: The purified sorbitol solution is concentrated to remove excess water, achieving a desired concentration.
• Crystallization and Drying: If necessary, sorbitol can be further crystallized and dried to obtain a solid form.

It occurs as a fine white powder or white crystals.

What it is used for and where

It is used as a raw material by fermentation and chemical synthesis to produce vitamin C. In addition to its moisturising sweetening effect, sorbitol has chelating, stabilising and moistening properties, particularly in toothpastes, cosmetics and tobacco.

Food

Labelled as E420 sweetener in the European list of food additives, sorbitol is found naturally in fruits such as pears, apples, cherries, sorbs, plums, etc., but is made industrially from glucose using a chemical process.

It is an artificial sweetener, widely used in food and pharmaceutical production for its sweetening properties.

Food sector.

• About 60% sugar sweetening power
• About 40% less calories than sugar
• Anti-mold properties
• Anti-leavening properties
• Preservative

Pharmaceutical 

Bulking agent in pharmaceutical products. ‘Bulking agents’ are substances which contribute to the volume of a foodstuff without contributing significantly to its available energy value (1).

Cosmetics

In cosmetic products, it has the function of retaining water and is also used as fragrance, humectant, skin conditioning, thickener, flow agent.

Fragrance. It plays a very important role in the formulation of cosmetic products as it allows perfume to be enhanced, masked or added to the final product, improving its commercial viability.  The consumer always expects to find a pleasant scent in a cosmetic product.

Humectant. Hygroscopic compound used to minimise water loss in the skin and to prevent it from drying out by facilitating faster and greater absorption of water into the stratum corneum of the epidermis.  The epidermis is the most superficial of the three layers that make up human skin (epidermis, dermis and hypodermis) and is the layer that maintains hydration in all three layers. In turn, the epidermis is composed of five layers: horny, the most superficial, granular, spinous, shiny, and basal. Humectants have the ability to retain the water they attract from the air in the stratum corneum and have the function of moisturising the skin. They are best used before emollients, which are oil-based.

Skin conditioning agent. An ingredient that is the mainstay of topical skin treatment by restoring, increasing or improving skin tolerance to external factors, including melanocyte tolerance. The most important function of the conditioning agent is to prevent skin dehydration, but the subject is rather complex and involves emollients and humectants.

Contraindications:

Diarrhea if the dose exceeds 40gr per day
Can give various intestinal disorders

Sorbitol studies

Typical optimal characteristics of Sorbitol as a commercial product

• Molecular Formula: C₆H₁₄O₆
• Molecular Weight: 182.172 g/mol
• CAS: 50-70-4  69-65-8  98201-93-5
• EC Number:200-061-5  619-324-4
• UNIII: 506T60A25R
• InChI=1S/C6H14O6/c7-1-3(9)5(11)6(12)4(10)2-8/h3-12H,1-2H2/t3-,4+,5-,6-/m1/s1  
• InChl Key      FBPFZTCFMRRESA-JGWLITMVSA-N
• SMILES    C(C(C(C(C(CO)O)O)O)O)O
• IUPAC   (2R,3R,4R,5S)-hexane-1,2,3,4,5,6-hexol
• ChEBI  17924
• Beilstein Registry Number:1721899
• MDL number:MFCD00004708
• PubChem Substance ID 329751137
• FEMA Number: 3029
• Synonyms:
• D-Sorbitol
• glucitol
• D-Glucitol
• Glucarine
• Sorbilande
• Diakarmon
• Sorbostyl
• Multitol
• Sorbex

References____________________________________________________________

(1) Regulation (EC) No 1333/2008 of the European Parliament and of the Council of 16 December 2008 on food additives (Text with EEA relevance)  OJ L 354, 31.12.2008, p. 16–33 (BG, ES, CS, DA, DE, ET, EL, EN, FR, GA, IT, LV, LT, HU, MT, NL, PL, PT, RO, SK, SL, FI, SV) 

We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular (1).

OBJECTIVE: To provide a comprehensive overview of published evidence on the impact of erythritol, a noncaloric polyol bulk sweetener, on oral health. METHODS:A literature review was conducted regarding the potential effects of erythritol on dental plaque (biofilm), dental caries, and periodontal therapy. The efficacy of erythritol on oral health was compared with xylitol and sorbitol. RESULTS:Erythritol effectively decreased weight of dental plaque and adherence of common streptococcal oral bacteria to tooth surfaces, inhibited growth and activity of associated bacteria like S. mutans, decreased expression of bacterial genes involved in sucrose metabolism, reduced the overall number of dental caries, and served as a suitable matrix for subgingival air-polishing to replace traditional root scaling. CONCLUSIONS: Important differences were reported in the effect of individual polyols on oral health. The current review provides evidence demonstrating better efficacy of erythritol compared to sorbitol and xylitol to maintain and improve oral health (2).

However, as a contraindication, it should be remembered that the accumulation of sorbitol is known to cause microvascular diabetic complications (3).

References___________________________________________

(1) Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.
Choudhary S, Save SN, Kishore N, Hosur RV.
PLoS One. 2016 Nov
(2) Erythritol Is More Effective Than Xylitol and Sorbitol in Managing Oral Health Endpoints.
de Cock P, Mäkinen K, Honkala E, Saag M, Kennepohl E, Eapen A.
Int J Dent. 2016
(3) A fiber-optic sorbitol biosensor based on NADH fluorescence detection toward rapid diagnosis of diabetic complications.
Gessei T, Arakawa T, Kudo H, Mitsubayashi K.
Analyst. 2015 Sep

Hyperglycemia Promotes Schwann Cell De-differentiation and De-myelination via Sorbitol Accumulation and Igf1 Protein Down-regulation.
Hao W, Tashiro S, Hasegawa T, Sato Y, Kobayashi T, Tando T, Katsuyama E, Fujie A, Watanabe R, Morita M, Miyamoto K, Morioka H, Nakamura M, Matsumoto M, Amizuka N, Toyama Y, Miyamoto T.
J Biol Chem. 2015 Jul