Erythritol Is It Bad for You?

Erythritol is a new functional sweetener that is widely found in fungi (such as mushrooms and seaweed), fruits and vegetables (such as cucumbers and grapes), and various fermented foods (such as beer and soy sauce), as well as in the body fluids and tissues of humans and animals (such as urine and blood) [1]. Erythritol has been used in many industries such as food, chemical, pharmaceutical and cosmetics due to its excellent processing characteristics, such as thermal stability, acid and alkali resistance, and low moisture absorption, as well as its functional characteristics, such as low calorie, low side effects and non-cariogenic properties [2-3]. Currently, erythritol is produced mainly by microbial fermentation and chemical synthesis.

1. The physical and chemical properties and physiological function characteristics of erythritol

1.1. The physical and chemical properties of erythritol

Erythritol is a natural four-carbon polyol with the chemical name 1,2,3,4-butanetetrol, molecular formula C4H10O4 and relative molecular weight 122.12. Its molecular structure is symmetrical. Erythritol does not contain a reducing aldehyde group in its molecular structure and has similar chemical properties to other polyols [4].

Erythritol has a pure sweet taste, and its sweetness is similar to that of sucrose. Its relative sweetness is 70%–80% that of sucrose. Importantly, it can be used in combination with some high-intensity sweeteners, such as acesulfame potassium and aspartame, to replace sucrose in foods. It is a white crystal or powder that is easily soluble in water. The aqueous solution is a colorless, transparent, non-viscous liquid with almost no hygroscopicity, even at 90% air humidity. The melting point of erythritol is 118°C to 122°C. It can absorb a lot of heat when dissolving, and the heat of dissolution in water can be up to three times that of glucose. It can be used in the manufacture of cooling foods. Erythritol is highly stable to both acids and high temperatures. Studies have shown that the recovery rate of erythritol in finished foods can reach 100%, so it can be used in baked or acidic foods [5-7].

1.2 Physiological function characteristics

1.2.1 Low caloric value

The caloric value of erythritol is about 1/10 that of sucrose. It is a non-metabolic low-calorie sugar alcohol. During metabolism, its small molecular weight allows it to be absorbed in the small intestine without being broken down, and then excreted from the body with the urine, without affecting body fat. Therefore, it can be used alone or in combination with other sweeteners to replace sucrose in the production of low-calorie foods. In addition, erythritol cannot be metabolized by the body's enzyme system, does not cause changes in blood glucose and insulin levels, and has no effect on sugar metabolism. Therefore, it can be used to develop foods suitable for obese and diabetic patients [8].

1.2.2 Anti-caries

The occurrence of dental caries is mainly due to the fermentation of the sugar substrate in the mouth by bacteria, especially Streptococcus mutans, which produces acid. This acid can destroy the enamel of the tooth through deionization, resulting in dental caries. Erythritol is difficult to be utilized by cariogenic bacteria in the mouth, and cannot be fermented by enzymes in the mouth to produce acid, so it has no effect on the teeth. Yang Qingling et al. reported that erythritol has a certain inhibitory effect on the fermentation of sugars by bacteria in the mouth [9].

1.2.3 Promotes the proliferation of probiotics

Erythritol is not only difficult to be utilized by bacteria in the mouth, but also by bacteria in the intestine. However, it has a significant proliferative effect on the intestinal probiotic Bifidobacterium, which in turn improves the body's immunity.

1.2.4 Antioxidant properties

Erythritol has antioxidant activity, can effectively scavenge free radicals in the body, and has a good inhibitory effect on the production of free radicals, thus helping to prevent vascular damage induced by high blood sugar [10]. It has been reported in the literature that erythritol reacts with free radicals to form erythrose and erythritol [11-13]. The results of zoological experiments also show that erythritol has the effect of protecting endothelial cells [14].

1.2.5 High tolerance

According to literature reports, 80% of the erythritol ingested by the body is absorbed in the small intestine, and very little enters the large intestine. Of this, 50% is excreted with the feces, and very little is retained in the large intestine. This effectively avoids the side effects of diarrhea and flatulence caused by non-absorbed substances. Therefore, erythritol is the most tolerable of the sugar alcohols [15]. Numerous animal and clinical experiments have also shown that erythritol is safe and non-toxic [16-17]. Research conducted by the Health Sciences Research Center at the University of Nebraska in the United States shows that the safe intake of erythritol in humans is 1 g/(kg body weight·d).

2 Research on the production process of erythritol

At present, the main methods of producing erythritol are chemical synthesis and microbial fermentation. Chemical synthesis is a process in which sugars are hydrogenated under high temperature and pressure to produce erythritol. This method is fast and efficient, and is suitable for large-scale production. However, it also has disadvantages such as high energy consumption, high pollution, harsh reaction conditions, and insufficient product purity [18]. With the increasing maturity of the technology for producing erythritol by microbial fermentation, the fermentation method has shown a number of advantages over the chemical synthesis method, such as mild production conditions, low energy consumption, and environmental friendliness. Therefore, the application of microbial fermentation to produce erythritol has also become a current research hotspot.

2.1 Chemical synthesis

Currently, there are two main methods of chemical synthesis: (1) using the periodate method to convert starch into diallyl starch, and then oxidizing it to obtain erythritol and other derivatives; (2) preparing 2-butene-1,4-diol from acetylene and formaldehyde alcohol, and then let butene-2,4-diol react with hydrogen peroxide, and mix its aqueous solution with a chromium catalyst, add the inhibitor ammonia water, and pass hydrogen gas under a pressure of 0.5 MPa to carry out a hydrogenation reaction to obtain erythritol [19]. The chemical synthesis method for producing erythritol is generally plagued by high requirements for conditions, serious pollution and poor product safety. However, the microbial fermentation method does not have these disadvantages, and therefore it has become the most researched and applied production method.

2.2 Microbial fermentation method

Initially, erythritol was produced using certain molds or yeasts through biotechnology. The microbial fermentation method involves first enzymatically digesting starchy raw materials such as corn or wheat to obtain glucose, and then using the fermentation of molds or high osmotic yeasts to obtain a mixture of polyols such as erythritol and ribitol. After filtration, concentration and refinement, erythritol can be obtained. Compared with chemical synthesis, this method has the advantages of mild production conditions and environmental friendliness [20]. At present, both domestically and abroad, erythritol is produced on a large scale using microbial fermentation. The fermenting microorganisms are mostly food-grade osmophilic yeasts, such as Candida lipolytica and Moniliella pllinis, and the yield of the product is about 50% [21-22].

3 Applications of erythritol

At present, the main application fields of erythritol include food, medicine and chemical industry. In recent decades, with the improvement of people's living standards and consumers' emphasis on food safety, nutrition and health, low-sugar or sugar-free foods are rapidly becoming a huge market. Erythritol is favored in the food industry due to its unique physical and chemical properties and functional characteristics [23-25].

3.1 Confectionery production

With the increase in childhood tooth decay, obesity and diabetes, the confectionery industry is gradually shifting from traditional products to low-sugar or sugar-free products. This has placed higher demands on sucrose substitutes, and the properties of erythritol meet these demands well [26]. With a caloric value of only 1.7 J/g, erythritol can effectively reduce the calories in the food being made, making it an ideal ingredient for low-calorie sweets. It also has a high tolerance, avoiding side effects such as bowel rumbling and diarrhea. Erythritol is non-hygroscopic, similar in appearance to granulated sugar, and can directly replace sucrose while maintaining the original process. The thermal and acid stability of erythritol ensures that browning and decomposition are effectively prevented in the production of hard candy. The high heat absorption of erythritol can be used in the production of chewing gum to give the product a long-lasting, refreshing and cooling sensation. In the production of confectionery, erythritol can be used alone or in combination with other sweeteners to produce products of excellent quality, and the texture and shelf life of the products produced are the same as those of traditional products.

3.2 Baked goods

Based on the above characteristics of erythritol, it is also widely used in baked goods. The safe dosage of erythritol in the formulation of common baked goods such as cakes, cookies and biscuits can reach 10%, which not only reduces the caloric value of the product, but also extends its shelf life. Wei Zhencheng et al. reported that the combination of erythritol and maltitol can completely replace sucrose to produce low-calorie sugar-free baked goods [27].

3.3 Beverages

Because of its stability in an acidic environment, erythritol has been used in recent years to develop new low-calorie beverages. According to reports by Gao Shengjun and Gao Shengjun, erythritol can effectively improve the sweetness, thickness and smoothness of beverages, while reducing their bitterness. In addition, erythritol can also extend the shelf life of fermented milk drinks by reducing the amount of acid produced during storage [28-29].

3.4 Table condiments

Erythritol not only provides a similar flavor, crystal structure and density to sucrose, but also exhibits good stability and fluidity due to the non-hygroscopic nature of its crystals, making it particularly suitable for use in combination with high-intensity sweeteners. Its use in table condiment formulations can improve texture and mouthfeel while also masking undesirable aftertastes.

4 Conclusion and outlook

Erythritol is a new type of polyol sweetener that has excellent processing characteristics and functional properties. It has been used in a variety of industries, including food, chemical, pharmaceutical, and cosmetics. This paper briefly introduces the physical and chemical properties, functional characteristics, and production process of erythritol, and provides an overview of its application in the food industry, providing a scientific reference for its further development and application.

With the improvement of people's living standards and changes in dietary structure, various health problems have become increasingly prominent, which has forced consumers to continuously improve their health awareness. Consumers have begun to reduce their intake of sugar and high-calorie foods, and have a great demand for functional health products such as sugar-free, low-calorie, and weight-loss products. Erythritol is a natural sweetener that is known as a “zero” ingredient, and it satisfies consumers' pursuit of taste and health. And because erythritol has a number of unique physical and functional properties, it is widely used in food, pharmaceuticals and chemical industries. Therefore, in the future food and health product industries, erythritol will be an indispensable healthy ingredient.

The “Research and Development of Erythritol”, a key national science and technology project during the Tenth Five-Year Plan undertaken by the China National Research Institute of Food & Fermentation Industries and related units, has made significant breakthroughs in the production of erythritol by microbial fermentation. The main technical parameters of the strain selection and production process have reached the international leading level, and pilot tests have been carried out. The microbial fermentation method uses starch as a raw material, which has the advantages of a rich source of raw materials, an environmentally friendly process, and high product safety. This method has become the mainstream method for producing erythritol [30]. With the continuous improvement of microbial fermentation technology, the continuous improvement of product quality, and the continuous reduction of production costs, the erythritol produced will be more competitive.

References:

[1] Jin Qirong, Jin Fengqiu. Development and application of erythritol [J]. Starch & Starch Sugar, 2002(3): 13-15.

[2] MUNRO IC, BERNDT WO, BORZELLECA JF, et al. Erythritol: an interpretive summary of biochemical, metabolic, toxicological and clinical data[J]. Food Chem Toxicol, 1998, 36(12): 1139-1174.

[3] You Xin. The function and industrial application development prospects of sugar alcohols [J]. China Food Additives, 2010(6): 45-52.

[4] Yang Libo, Zheng Zhiyong, Zhan Xiaobei. Glycine and proline promote the fermentation of glycerol by Yarrowia lipolytica to produce erythritol in a hyperosmotic environment [J]. Food and Fermentation Industry, 2013(12): 1-6.

[5] TOMASZEWSKA L, RYWINSKA A, MUSIAL I, et al. Effect of vitaminssource on erythritol biosynthesis by Yarrowia lipolytica WratislaviaK1[J]. Current Opinion in Biotechnology, 2011, 22(S1): S94-95.

[6] Yu Limei, Bai Weidong, Yang Min, et al. Development of erythritol sesame soft candy and evaluation of its efficacy [J]. Journal of Zhongkai University of Agriculture and Engineering, 2012, 25(3): 30-31, 36.

[7] HARTOG GJ, BOOTS AW, BROUNS F, et al. Erythritol is a sweet antioxidant[J]. Nutrition, 2010, 26(4): 449-458.

[8] GEOFFREY LIVESEY. Health potential of polyols as sugar replaces, with emphasis on low glycaemic properties[J]. Nutrition Research Review, 2003(16): 163-191.

[9] Yang Qingling, Lu Wei, Pei Pengfei, et al. Effect of erythritol on the growth and acid production of major cariogenic Streptococcus and fluororesistant strains [J]. Chinese Journal of Microecology, 2012, 24(2): 139-141.

[10] Gao Shengjun, Mao Jun. Study on the protective effect of erythritol on vitamin C in lemon juice beverage [J]. Food Industry Science and Technology, 2014(3): 49-51.

[11] Fang Hua, Li Hao. The role of trehalose and heat shock protein in the tolerance of ethanol stress in Saccharomyces cerevisiae [J]. Chinese Journal of Bioengineering, 2014, 34(6): 84-89.

[12] Chen Yibing, Tian Li, Song Ning. Research progress of cryopreservation protectants for human red blood cells [J]. Chinese Journal of Blood Transfusion, 2015, 28(3): 338-341.

[13] Zhang Xiaoyan, Yun Xueyan, Liang Min. The effect of a biodegradable film containing trehalose on the preservation and color protection of chilled meat [J]. Food Industry Science and Technology, 2015, 36(8): 298-304.

[14] Yang YZ, Li F, Shuai B, et al. Application of erythritol, a natural healthy sugar alcohol, in low-energy foods [J]. China Food Additives, 2013(1): 181-185.

[15] Jiang SQ, Ma L. Development and research of new starch sugar products [J]. Food Industry Science and Technology, 2002, 22(3): 83-85.

[16] Fu Yong, Xu Caiju, Mao Guangming. Experimental study on the acute toxicity and genotoxicity of erythritol [J]. Detection Research · Carcinogenesis · Teratogenesis · Mutagenesis, 2003, 15(1): 54-55.

[17] MMRRO I C. BERET W O, BORZELECA J F, et al. Erythritol: An interpretive summary of biochemical, metabolic, toxicological and clinical data[J]. Food Chem Toxicology, 1998(36): 1139-1174.

[18] Fan J, Han Y, Zhou Z, et al. Research progress in the production of sugar alcohols by microbial fermentation [J]. Food and Fermentation Science and Technology, 2013(3): 13-15.

[19] Liu J, Zhao X, Tian Y, et al. Low-calorie sweetener erythritol [J]. Food and Fermentation Industry, 2007, 33(9): 132-135.

[20] Xu Ying, Li Jingjun, He Guoqing. Research progress and application of erythritol in food [J]. China Food Additives, 2005(03): 92-96.

[21] SAVERGAVE LS, GADRE RV, VAIDYA BK, et al. Strain improvement andstatistical media optimization for enhanced erythritol productionwith minimal by-products from Candida magnoliae mutant R23[J]. Biochemical Engineering Journal, 2011, 55(2): 92-100.

[22] GAO XL, SENVIRATNE CJ, LO EC, et al. Novel and conventional assays in determining abundance of Streptococcus mutans in saliva[J]. Int J Paediatr Dent, 2012, 22(5): 363-368.

[23] Zhang Yuhui, Duan Yingying, Zhao Wei, et al. Research on the optimization of trehalose conversion conditions [J]. Food Industry, 2014(30): 96-98.

[24] Teng Xiaohuan, Zhang Yinliang, Hu Xiaoming. The effect of trehalose and sodium stearoyl lactylate on bread quality [J]. Food Science and Technology, 2015(1): 172-177.

[25] Xu Guofa, Chen Ping, Zhang Jianbo, et al. Determination of the content change of the sweetener erythritol in the intracellular and extracellular fluids of PC12 cells by RP-HPLC [J]. China Food Additives, 2016(1): 133-140.

[26] Liu Dan, Yin Xianfeng. Process research on low-calorie functional jelly of Ophiopogon japonicus [J]. Food Research and Development, 2014, 35(6): 63-65.

[27] Wei Zhencheng, Zhang Mingwei, Chi Jianwei, et al. Development trends and prospects of China's baked goods industry [J]. Food Research and Development, 2007, 28(11): 182-184.

[28] Gao Zhishan, Wei Huaisheng. A production process for a fermented low-energy alcohol-free clarified hawthorn beverage [J]. Food Research and Development, 2015, 36(13): 73-75.

[29] Gao Shengjun, Mao Jun. Study on the protective effect of erythritol on vitamin C in lemon juice beverage [J]. Food Industry Science and Technology, 2014, 35(3): 49-52.

[30] Fan Guangsen, Zhu Siyue, Duan Shenglin, et al. Optimization of zero-calorie jelly powder formulation based on response surface [J]. Food Industry Science and Technology, 2016(2): 296-306.