What is guar gum in food ingredient lists? Is it safe? Experts: Don’t be afraid of it!

Abstract: Edible gum is a widely used food additive in the world. Guar gum is widely used in food due to its advantages of multiple physical, biological and chemical activities. For human food, the National Food Safety Standard for the Use of Food Additives (GB 2760-2014) indicates that the maximum allowable amount of guar gum in cream is 1000 mg/kg, and in formula foods for older infants and young children is 1000 mg/L. The domestic Feed Additive Variety Catalogue (2008) clearly states that guar gum is a pet stabilizer and emulsifier that is allowed to be used. The Safe Use of Feed Additives Specifications points out that most edible gums are recommended to be used in pet food in appropriate amounts according to production needs, with a high safety factor. In addition to domestic regulations, the European Union, the European Food Safety Authority Animal Food Additives and Products (FEEDAP) Group, and the Codex Alimentarius Commission (CAC) have also made regulations on the use of guar gum in human or pet food. Combined with relevant academic research on guar gum, it can be seen that the appropriate use of guar gum is generally safe and harmless and may bring health benefits to humans or animals. In addition, when testing the guar gum content in food, if it is found to be excessive, the test method and results should be verified for deviations, and the content should be reviewed and evaluated to see if it is really excessive. As long as guar gum is used in an appropriate amount in strict accordance with national standards, the safety of food additives can be guaranteed, and toxicity cannot be discussed without considering the dosage.

1. Introduction of guar gum

Edible gum is a widely used food additive in the world. Edible gum is used in almost all foods. There are many types of edible gum, most of which are extracted from plants, seaweed, microorganisms and animals. There are about 60 types of edible gum allowed for use in the world, and about 40 types are allowed for use in my country. The most widely used monomer edible gums include carrageenan, xanthan gum, guar gum, konjac gum, locust bean gum, edible gelatin, alginate and agar. The sources of edible gum are detailed in Table 1[1].

Table 1. Sources of edible gums[1]

Guar gum is derived from the endosperm of the pods of guar beans (Cyamopsis tetragonolobus (L.) Taub) of the Leguminosae family. The main component is a high molecular weight hydrophilic polysaccharide, which is composed of galactose and mannose as basic sugar units and belongs to galactomannan. Guar gum is one of the most widely used hydrophilic colloids in the world. Guar gum powder is generally white to light brown powder, without any peculiar smell, and can be dissolved in cold or hot water to form a colloidal solution. It has the highest viscosity among natural gums [1].

Guar gum has a variety of physical, biological and chemical activities and is relatively safe for humans and animals and does not pollute the environment. Therefore, it is widely used in food and pet food. It is often used as a thickener, stabilizer, preservative or a source of natural dietary fiber[2]. It is usually used alone or in combination with other edible gums[1].

2. The dosage used is closely related to food safety, and toxicity cannot be discussed without considering the dosage.

The physiological effects of edible gum have been widely studied in animals and humans, and there are different opinions on the toxicity of edible gum, which mainly depends on its dosage. Therefore, we need to pay attention to the amount of edible gum used in human or pet food to ensure safety.

In addition, for human food, China's "National Food Safety Standard for the Use of Food Additives" (GB 2760-2014) states that the maximum allowable amount of guar gum in cream is 1000 mg/kg, and in formula for older infants and toddlers it is 1000 mg/L (calculated based on the amount used in ready-to-eat foods) (see Table 2) [6].

Table 2. China Food Additive Usage Standards - Guar Gum

The Ministry of Agriculture of the People’s Republic of China’s Announcement No. 1126, “Catalogue of Feed Additives (2008)”, states that edible gums such as guar gum, xanthan gum, carrageenan, cassia gum, locust bean gum, etc. are permitted binders, anti-caking agents, stabilizers and emulsifiers for use in pet food (see Table 3) [3].

Table 3. Catalog of pet food additives - guar gum

In order to effectively strengthen the management of pet food additives, ensure the quality and safety of pet food additives, and promote the sustainable and healthy development of the pet food industry and breeding industry, the Ministry of Agriculture of the People's Republic of China (2017) No. 2625 "Safety Use of Feed Additives" stipulates the amount of edible gum used: most edible gums such as carrageenan, cassia gum, locust bean gum, etc. are recommended to be used in appropriate amounts according to production needs in pet food or total mixed diets. Among them, the maximum limit of cassia gum in pet food or total mixed diets is 17,600 mg/kg (see Table 4) [4], which has a high safety factor.

Table 4. Safe Use Specifications for Pet Food Additives - Binders, Anti-caking Agents, Stabilizers and Emulsifiers

The "Safety Standards for the Use of Feed Additives" has not yet stipulated the amount of guar gum used in pet food. It is generally believed that an appropriate amount of guar gum is safe and harmless, and relevant research has also confirmed this.

Based on a comprehensive fertility/developmental study on rats, the expert group determined that the no observed adverse effect level (NOAEL) for guar gum at 5200 mg/kg body weight per day (equivalent to 5.2 times the national standard limit) was 5200 mg/kg body weight per day (equivalent to 5.2 times the national standard limit) based on the number of corpora lutea. In another test on the highest dose of guar gum in rats at 2500 mg/kg body weight per day (equivalent to 2.5 times the national standard limit), no carcinogenic effects were reported [5]. It can be seen that the appropriate use of guar gum has no toxic side effects.

In addition to domestic regulations, foreign regulations also regulate the use of guar gum in human or pet food.

According to the Food Additives Regulation (EC) No 1333/2008, guar gum is authorized as a human food additive in the EU. Guar gum can be used in sufficient quantities in most foods. The maximum amount of guar gum used in some foods is specified, see Table 5 [5].

Table 5. European Food Additive Usage Standards - Guar Gum

The Codex Alimentarius (CAC), jointly established by the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO), updated the Codex General Standard for Food Additives (Codex STAN 192-1995), clarifying the use of guar gum in human food. For example, the maximum amount used in infant food is 1000-2000 mg/kg, and the amount added to other foods should be as low as possible and in compliance with good manufacturing practices (GMP). See Table 6 for details [8].

Table 6. CAC General Codex Standard for Food Additives - Guar Gum

At the request of the European Commission, the European Food Safety Authority was asked to issue a scientific opinion on the safety and effectiveness of guar gum as a food additive for animal species. Based on the results of the tolerability study, the FEEDAP panel concluded that the maximum safe concentration of guar gum for use in pet food is 1320 and 1100 mg/kg for dogs and cats, respectively (see Table 7) [7].

Table 7. FEEDAP Research Group - Maximum safe concentrations of guar gum in pet food

In academic research related to guar gum, such as the evaluation of guar gum by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), there was a study on beagles, in which five male and five female beagles were divided into four groups and fed with food containing 0%, 1%, 5% or 10% guar gum (equivalent to approximately 0, 750, 3750 and 7500 mg/kg body weight per day) for 30 weeks. At a dose of 10% guar gum (equivalent to 7.5 times the national standard limit), rapid intestinal motility, loose stools and reduced digestibility were observed, while no adverse reactions were found at doses of 1% and 5% (equivalent to 75% and 3.75 times the national standard limit, respectively) [5].

In addition, low-dose guar gum may also bring health benefits to humans or animals. Fifteen rats were fed a diet containing 0.5% guar gum (equivalent to 600 mg/kg body weight per day, 60% of the national standard limit) and different amounts of water for 21 days. The study showed that the rats gained weight and improved protein efficiency. Adults were well tolerated when taking 128–429 mg/kg body weight (equivalent to 12.8%-42.9% of the national standard limit) of guar gum orally per day [5]. A single-center, single-arm, open-label, proof-of-concept study enrolled 12 healthy men to test the effects of taking 88-133 mg/kg (equivalent to 8.8%-13.3% of the national standard limit) of guar gum per day for 18 consecutive days on microbiome metabolism and adaptation. The results showed that 88-133 mg/kg guar gum was well tolerated in healthy men and exerted selective regulatory effects on the human microbiome at the taxonomic and functional levels. In addition, guar gum regulates the absorption of nutrients in the small intestine and has beneficial effects on cholesterol metabolism and blood sugar control[9].

Considering the widespread use of edible gum in pet food, the FEEDAP expert group and related studies have summarized the effects and benefits of safe doses of edible gum in pet food, see Table 8 for details.

Table 8. Effects/benefits of adding edible gum to pet food

Combining the relevant academic research on guar gum and comparing it with the national standard for the limit of guar gum in human food (1000mg/kg), it can be seen that the appropriate use of guar gum is generally safe and harmless, and low doses may have health benefits for humans or animals. Only at high doses can guar gum produce slight adverse reactions, but such high doses of guar gum are generally not added to food and pet food production, so there is no need to worry too much. It can be seen that the role and impact of guar gum in pet or human food cannot be generalized. Neither toxicity can be discussed without considering the dose, nor can the function be discussed without considering the dose.

3. Detection Method

How do we know whether the guar gum content in food meets the above standards?

According to the relevant provisions of the Food Safety Law of the People's Republic of China and its implementing regulations, the State Administration for Market Regulation has approved and issued 10 food supplementary inspection methods and 9 food rapid detection methods. Among them, the "Determination of Guar Gum in Animal-derived Foods" (BJS 202301) mentions a liquid chromatography-tandem mass spectrometry method for the determination of guar gum in pork, beef and mutton. The sample and standard are hydrolyzed by β-mannanase, acetonitrile is added to precipitate the protein and then centrifuged. The supernatant is purified by a neutral alumina column and the characteristic oligosaccharides of the enzymatic hydrolysis product are detected by liquid chromatography-tandem mass spectrometry (when different instruments are used, the instrument parameters may be different, and the instrument parameters should be optimized to the best before determination). The guar gum content is determined by the external standard method. Precision: Under repeatability conditions, the absolute difference between two independent determination results shall not exceed 10% of the arithmetic mean. The detection limit of this method is 3.00 mg/kg, and the quantification limit is 10.0 mg/kg. If characteristic oligosaccharides of guar gum enzymatic hydrolysis products are detected in the sample, the source may be guar gum[13].

It can be seen that different detection methods and instruments will cause certain deviations in the determination of guar gum content. The results of a single measurement also need to be reviewed to assess whether the content is actually exceeding the standard and whether there is a safety risk.

IV. Conclusion

In summary, guar gum and other edible gums are often used as binders, anti-caking agents, stabilizers, etc. in pet food, and are safe to use in moderation. If the guar gum content in pet food exceeds the standard, there is no need to worry too much. You should first verify whether there is any deviation in the test method and results, and review and evaluate whether the content is really excessive. As long as guar gum and other edible gums are used strictly in accordance with the scope of use, dosage and method of use specified in national standards, the safety of food additives can be guaranteed [14].

References:

[1] Bai Mingyin. Common edible glues in meat products and their applications [J]. Food Safety Guide, 2010(1): 50-52.

[2] Huang Jie, An Qiufeng. Research progress of guar gum[J]. Food Research and Development, 2011, 32(1): 144-147.

[3] Announcement No. 1126 of the Ministry of Agriculture of the People’s Republic of China (2008) “Catalogue of Feed Additives”.

[4] Announcement No. 2625 of the Ministry of Agriculture of the People’s Republic of China (2017) “Safety Specifications for the Use of Feed Additives”.

[5]EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), et al. EFSA J. 2017 Feb 24; 15(2): e04669.

[6] National Food Safety Standard - Standard for the Use of Food Additives (GB 2760-2014).

[7]EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), et al. EFSA J. 2022 Apr 29; 20(4): e07253.

[8] Codex General Standard for Food Additives (Codex STAN 192-1995).

[9]Barber C, et al. Front Nutr. 2023 Jun 30; 10: 1160694.

[10]Azevedo R, et al. Foods. 2023 Mar 26; 12(7): 1408.

[11]EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), et al. EFSA J. 2022 Apr 29; 20(4): e07285.

[12]EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), et al. EFSA J. 2022 Aug 5; 20(8): e07435.

[13] “Determination of guar gum in animal origin foods” (BJS 202301).

[14] Qian He, et al. Function and risk control of chemical additives in food[J]. Progress in Chemistry, 2009, 21(11): 2424-2434.

author:

Zhao Yue | Senior Regulator of Food Industry, China Agricultural University

Reviewers:

Dai Xiaofeng | Second-level researcher and doctoral supervisor at the Chinese Academy of Agricultural Sciences