Carob Seed: Structure, Locust Bean Gum (E410), Uses and Sales
The carob seed is the hard, glossy brown seed set in the compartments of the sweet pulp inside the carob fruit (Ceratonia siliqua L.). To someone eating the fruit it may look like the part that gets "picked out and thrown away", but in the carob industry the opposite is true: locust bean gum (carob bean gum, E410), obtained from the seed's endosperm, is a valuable natural thickener used in a wide range of products, from ice cream to infant formula.
In this article we cover the carob seed from every angle: the parts of the seed, how many seeds a pod contains, gum production from the seed, the uses of the gum and of germ meal, its connection to the word "carat", the characteristics of the seed market, and what to look out for when buying carob seed.
What Is Carob Seed?
The carob seed is the seed inside the carob pod. It is flat and oval, with a very hard, glossy brown coat; when the fruit is fully ripe and dry, the seeds loosen in their compartments and rattle when the pod is shaken. Because of this hardness the seed is not eaten with the fruit; industry processes it using special methods.
| Feature | Details |
|---|---|
| Source | Carob (harnup) pod |
| Share of the pod | Approximately 10–25% by weight; varies by cultivar and region |
| Parts | Seed coat (hull), endosperm and germ (embryo) |
| Main product | Locust bean gum (carob bean gum, E410) |
| By-product | Protein-rich germ meal |
| Uses | Food, infant foods and foods for special medical purposes, pet food, pharmaceuticals, cosmetics, textiles |
For the general characteristics of carob, see our guide What Is Carob (Harnup)?
Structure of the Seed: Seed Coat, Endosperm and Germ
From the outside in, the carob seed consists of three parts, and each has its own industrial use:
- Seed coat (hull): The hard, dark brown layer enclosing the seed. It is removed (dehulled) during gum production.
- Endosperm: The whitish tissue beneath the seed coat. It is the actual source of locust bean gum.
- Germ (embryo): The protein-rich part at the centre of the seed. As a by-product of gum production it is turned into germ meal.
As reported by Medronho and colleagues, the seed coat makes up roughly 30–35 percent of the seed's dry weight, the endosperm 40–50 percent and the germ 15–30 percent (Medronho et al., 2025). A Turkish study drawing on Batlle and Tous's monograph on carob gives the proportions as 30–33 percent for the seed coat, 42–46 percent for the endosperm and 23–25 percent for the embryo.
The European Food Safety Authority's report states, based on information from industry, that carob seeds are difficult to process because the seed coat is very hard and tough (EFSA, 2017). This is why the most critical step in gum production is removing the seed coat without damaging the endosperm.
How Many Seeds Are in a Pod?
The general figure most often cited in international sources is that the seed accounts for about 10 percent of the pod's weight; a recent review, however, stresses that this share ranges between 10 and 25 percent (Correia and Pestana, 2024). The main factor behind the difference is the type of tree: one review notes that seeds make up 8–12 percent of pod weight in grafted cultivars but 16–20 percent in ungrafted wild types (Dahmani et al., 2023).
Growing location matters too. In wild carob collected from different districts of Antalya, seed yield varied markedly from one district to another (Balkıç et al., 2024):
| District | Seeds per pod (count) | Seed yield (%) |
|---|---|---|
| Demre | 14.95 | 26.80 |
| Kumluca | 12.12 | 21.85 |
| Gazipaşa | 10.52 | 21.60 |
| Alanya | 10.24 | 20.26 |
| Manavgat | 10.60 | 16.43 |
The researchers reported that seed yield was higher in southern and low-altitude locations. This finding shows how important the choice of cultivar and planting material is in orchards aimed at seed and gum production. We discuss pod structure in detail in our article Carob Varieties.
What Is Locust Bean Gum (E410)?
Locust bean gum is the ground endosperm of carob tree seeds; in the international literature it is known as "locust bean gum" or "carob bean gum", and as a food additive it is identified by the code E410 (EFSA, 2017). The gum is obtained from the seed, not from the fruit's pulp; its composition and function are therefore completely different from those of carob flour or carob powder.
The main component of the gum is a high-molecular-weight polysaccharide called galactomannan. Sparse galactose side chains are attached to a linear backbone of mannose units; the mannose-to-galactose ratio is about 4:1. According to information from industry, the gum contains 87–88 percent galactomannan on a dry basis; the remainder is mainly protein and fibrous residues (EFSA, 2017).
This structure gives the gum three important properties: it forms a viscous system with water, limits ice crystal growth in ice cream, and shows strong synergy with certain hydrocolloids such as carrageenan and xanthan, strengthening the gel structure. E410 is a permitted additive according to EFSA's 2017 re-evaluation and the Turkish Food Codex Regulation on Food Additives; for the conditions of use in a specific product, the current annexes of the regulation should be consulted. For more detail, take a look at our article What Is Locust Bean Gum (E410)?
From Seed to Gum: How Is It Produced?
Locust bean gum production begins with kibbling the fruit to separate the seed from the pulp. At the gum plant, the following steps are then carried out (EFSA, 2017):
- Cleaning and grading: The seeds are separated from foreign matter, pulp residues and defective seeds.
- Dehulling: The hard seed coat is removed without damaging the endosperm and the germ.
- Germ separation: During splitting, the more brittle germ crumbles and is sieved off from the endosperm halves.
- Milling and sieving: The endosperm is milled and sieved to obtain "natural" locust bean gum.
Three basic methods are used for dehulling, and the method directly affects the colour and viscosity of the gum:
| Method | How is it done? | Effect on the result |
|---|---|---|
| Acid (sulphuric acid) | The seed coat is carbonised with acid at high temperature, then washed and brushed off | White, high-viscosity gum; the most common method in industry |
| Roasting (thermal) | The seeds are roasted in a rotary kiln and the seed coat is separated | No acidic wastewater; the gum may be slightly darker |
| Hot water | The seeds are soaked in boiling water and the seed coat is removed mechanically | No chemicals used; yellowish gum with lower viscosity |
A master's thesis carried out in Türkiye compared the three methods: the lowest protein content (5.01 percent) and the highest viscosity (533.9 mPa·s) were found in gum obtained by the sulphuric acid method, and the lowest viscosity (260.9 mPa·s) in gum obtained by the water method (Kıvrak, 2011). Refined (clarified) gum, a purer form, is produced by dissolving natural gum in hot water, filtering it and precipitating it with alcohol (EFSA, 2017). For details, see our article Locust Bean Gum (E410).
Uses of Locust Bean Gum
Locust bean gum is one of the most widely used natural hydrocolloids in the food industry; in some applications it is preferred over thickeners such as guar gum and carrageenan (Laaraj et al., 2023). Its main uses are:
- Ice cream and frozen desserts: Controls ice crystal formation and gives a smooth texture.
- Dairy products: Provides body and stability in cream cheese, yoghurt and milk-based desserts.
- Infant foods and foods for special medical purposes: EFSA notes that the EU Scientific Committee on Food accepted the gum's use in weaning foods in 1991 and in infant formulae for special medical purposes in 1994 (EFSA, 2017).
- Sauces, creams and ready-made desserts: Used as a thickener and stabiliser.
- Pet food: Common in canned pet food because, together with carrageenan, it forms a jelly-like structure.
- Non-food applications: Also used in the pharmaceutical, cosmetics and textile industries (Laaraj et al., 2023).
For the gum's technical properties and regulatory status, see our article What Is Locust Bean Gum (E410)?
Germ Meal: The Seed's Protein Store
After the endosperm has been separated during gum production, the remaining germ is dried and milled into carob germ meal. This meal is a natural by-product of gum production and is rich in protein: in a sample of industrial-grade germ meal, crude protein was measured at 54.7 percent, fat at 6.6 percent, ash at 6.5 percent and moisture at 8.3 percent (Dakia et al., 2007).
What makes germ meal interesting is that some of its proteins, when kneaded with water, form an elastic, extensible network resembling wheat gluten. Feillet and Roulland confirmed the viscoelastic properties of this protein complex through rheological measurements and named it "caroubin" (Feillet and Roulland, 1998). This property makes germ meal a raw material under investigation in gluten-free product development.
In this way, the seed's endosperm yields gum and its germ yields a flour valuable for its protein; making use of the compounds contained in the seed coat is also a subject of current research (Medronho et al., 2025).
The Carat and the Carob Seed: Myth or Fact?
The statement "Carob seeds all weigh the same; that is why jewellers used them as weights, and that is where the carat comes from" is partly true and partly myth.
The true part: The word carat really does come from the carob seed. The Greek "keration", meaning "little horn", referred both to the carob seed and to a small unit of weight; the word passed into Arabic as "qīrāṭ" and from there, via the Italian "carato", into European languages (Online Etymology Dictionary; Kallek, TDV İslâm Ansiklopedisi). The 200-milligram metric carat used today, however, was standardised at the beginning of the 20th century.
The myth: The claim that the seeds are remarkably uniform in weight has not been confirmed by scientific measurement. In the study by Turnbull and colleagues, the coefficient of variation in carob seed weight was found to be 23 percent, while the average for 63 species compiled from the literature was 25 percent. In other words, carob seeds are not noticeably more "uniform" than ordinary seeds (Turnbull et al., 2006). The full story is in our article The History of Carob.
The Carob Seed Market: Why Is It Valuable and Volatile?
The value of carob seed comes from the demand for locust bean gum. The supply side, however, is quite tight and cannot be increased in the short term. The main reasons are:
- The gum is obtained not from an annual crop but from a long-lived tree that takes years to come into bearing.
- Production is concentrated in a few Mediterranean countries.
- World carob production has declined over the long term: from a reported figure of about 650,000 tonnes in 1945, it fell to an average of about 184,000 tonnes in 2012–2021 (Mahdad and Gaouar, 2023).
- Drought and weather conditions make the harvest fluctuate from year to year.
- The seed accounts for only a small part of the pod by weight.
Because of this structure, seed and gum prices fluctuate depending on the harvest, demand, the situation of substitute products such as guar gum, and quality grade. For Türkiye, too, seed is tracked as a separate export item; according to the tables in a West Mediterranean Development Agency (Batı Akdeniz Kalkınma Ajansı) report, the value of Türkiye's carob seed exports rose every year from 2019 to 2022, roughly doubling (Erbaş, 2024). For details of the market, see our article Türkiye's Carob Exports.
What to Look for When Buying Carob Seed
Buyers of carob seed are mostly gum manufacturers and their suppliers. The main criteria that determine quality in these purchases are:
- Cleanliness: Pulp residues, dust, stones and other foreign matter should be kept to a minimum.
- Seed integrity: The proportion of broken, holed, crushed and rotten seeds should be low; seeds showing pest damage reduce yield and quality.
- Dryness: Moist seed is prone to mould and quality loss in storage; the moisture content should be documented by analysis.
- Uniformity: Seed size and colour should be uniform throughout the lot, with no mixing from different sources.
- Origin and harvest year: The region and season the product comes from should be known.
- Analyses and documentation: In line with the buyer's specification, results for moisture, foreign matter and, where necessary, other analyses should be requested.
Acceptance criteria, sampling method and packaging conditions should be clearly set out in the contract between buyer and seller. For general purchasing principles, see our article What to Consider When Buying Carob Wholesale.
Carob Seed Sales with Carob Türkiye
At Carob Türkiye, we supply seed separated from carob grown along the Mediterranean coast to gum manufacturers and industrial buyers, for wholesale and export. For product specifications, packaging options and analysis documents, see our Carob Seed product page.
If you are looking for raw materials made from the pulp, you can also browse our Carob Kibble (Granules), Carob Flour (Powder) and Carob Extract pages. For quantities, delivery terms and a price quote, get in touch with us.
Frequently Asked Questions About Carob Seed
What is carob seed used for? The seed's endosperm yields locust bean gum (E410), used in the food industry as a thickener and stabiliser. The germ is used to produce protein-rich germ meal.
Can you eat carob seeds? No. The seeds are very hard; they are removed when eating the fruit, and you should not try to crack them with your teeth.
Are locust bean gum and carob flour the same thing? No. Carob flour is made from the fruit's sweet pulp, while locust bean gum is obtained from the seed's endosperm; their composition and uses differ.
Is E410 harmful? E410 is a permitted food additive in the European Union and in Türkiye; EFSA re-evaluated it in 2017. Its conditions of use are set by legislation.
How many seeds are there in a carob pod? It varies by cultivar and region. The geographical indication registration document for Alanya Carob states that a pod contains 13–15 seeds; in wild types in Antalya, average values of between 9 and 15 have been measured.
Does the word carat come from carob? Yes, the word comes from the Greek "keration", meaning carob seed. However, the idea that all the seeds weigh the same is a myth.
What determines the price of carob seed? The harvest, demand for gum, the situation of substitute products, seed quality and level of cleanliness are the main factors determining the price. For a current quote, contact us.
EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), Mortensen, A. et al., "Re-evaluation of locust bean gum (E 410) as a food additive", EFSA Journal, 15(1), e04646, 2017. doi.org/10.2903/j.efsa.2017.4646
Medronho, B. et al., "On the Optimization of Carob Seed Peel Extraction Using Aqueous-Based Acidic Systems", Molecules, 30(7), 1397, 2025. doi.org/10.3390/molecules30071397
Correia, P. J., Pestana, M., "Sugars and phenols in carob tree fruits from different producing countries: A short review", Heliyon, 10, e30922, 2024. doi.org/10.1016/j.heliyon.2024.e30922
Dahmani, W. et al., "Exploring Carob (Ceratonia siliqua L.): A Comprehensive Assessment of Its Characteristics, Ethnomedicinal Uses, Phytochemical Aspects, and Pharmacological Activities", Plants, 12(18), 3303, 2023. doi.org/10.3390/plants12183303
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Kıvrak, N. E., "Farklı kabuk soyma yöntemleri kullanılarak keçiboynuzu çekirdeklerinden üretilen gamın bazı fiziksel ve kimyasal özelliklerinin belirlenmesi" (in Turkish), Master's thesis, Süleyman Demirel Üniversitesi, 2011. acikerisim.sdu.edu.tr
Dakia, P. A., Wathelet, B., Paquot, M., "Isolation and chemical evaluation of carob (Ceratonia siliqua L.) seed germ", Food Chemistry, 102(4), 1368–1374, 2007. doi.org/10.1016/j.foodchem.2006.05.059
Feillet, P., Roulland, T. M., "Caroubin: a gluten-like protein isolated from carob bean germ", Cereal Chemistry, 75(4), 488–492, 1998. doi.org/10.1094/CCHEM.1998.75.4.488
Turnbull, L. A., Santamaria, L., Martorell, T., Rallo, J., Hector, A., "Seed size variability: from carob to carats", Biology Letters, 2(3), 397–400, 2006. doi.org/10.1098/rsbl.2006.0476
Online Etymology Dictionary, "carat". etymonline.com/word/carat
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