Carob Extraction Technologies
What products such as carob must, molasses, syrup and extract have in common is that the soluble components in the fruit are transferred to a solvent, most often water. This stage is called extraction and the method used; It directly affects sugar yield, amount of phenolic compounds, taste, color and production time.
In this article, we comparatively discuss the extraction technologies used in carob, from traditional aqueous extraction to ultrasound and microwave-assisted methods, and from there to purification and enrichment techniques, in the light of scientific studies.
What is Extraction and Why is it Important in Carob?
Extraction is the transfer of the desired components in a raw material from the solid structure to the liquid phase with the help of a suitable solvent. The pulp of the carob fruit contains high levels of sugar, fiber and phenolic compounds. According to Antoniou et al. (2020) from the Cyprus Agricultural Research Institute, carob cracks contain about 48–56 percent sugar, about 40 percent crude fiber, 2–7 percent protein, and 1.4–2.0 percent total polyphenols over dry weight.
The same study defines the aqueous extraction of carob crumbs as the "basic step" in the production of carob must and molasses. Because molasses or syrup is actually the condensed form of this must. Therefore, the more sugar passes into solution in the extraction, the more efficient production can be made in the next thickening stage.
The difficulty of extraction is due to the fibrous structure of carob. In a doctoral thesis conducted at Munzur University (Eroğlu, 2020), it is stated that the extraction time can be extended from 12 hours to 3 days to obtain must in traditional carob molasses production, which is due to the difficult dissolution of sugar due to the fibrous structure of the fruit. Most of the new extraction technologies have been developed to shorten this period or increase the yield.
Traditional Aqueous Extraction
The most common and oldest method is to soak crushed carob in water or heat it and bring it into contact with water. The advantage of this method is its simplicity and the fact that it does not require organic solvents; therefore, it is natural to prefer water for food products.
Antoniou et al. examined four key variables that influence yield in aqueous extraction: the source of the raw material, kibble size, temperature, and duration. The study's notable findings include:
- The factor that determined the amount of phenolic compounds the most was the source of the raw material.
- The source of the raw material also affected the ratio of sucrose, glucose, and fructose to each other; this could alter the perceived sweetness of the must.
- Increasing the temperature from 25 °C to 75 °C in heat-assisted extraction passed phenolics into more solution than sugars.
- Extending the period at 25 °C improved sugar yield without causing an excessive increase in phenolics.
This conclusion is important in practice: The concept of "hotter water, better extraction" is not always correct. High temperature can pass more phenolic compounds into the wort, shifting the taste of the product towards astringency. The researchers note that relying on heat support to increase sugar yield remains limited, while longer extraction in conditions close to ambient temperature can increase sugar yield by keeping phenolics low.
Impact of Part Size
Mass transfer generally accelerates as the surface area of contact with the solvent increases in extraction. Antoniou et al. compared two kibble sizes: a medium kibble of 9–13 mm and a dust-sized kibble of 1–4 mm. The effect of kibble size was found to be more pronounced in ultrasound-assisted extraction than in the heat-assisted method, but this effect decreased as the ultrasound time was extended.
A practical observation of the researchers is also worth noting: in trials with light mixing, powder-sized kibble settled to the bottom and prevented the circulation of the solvent, while this problem was overcome with continuous ultrasound application. The study states that powder-sized kibble are an inevitable and low-cost by-product of industrial carob crushing, often used as feed or in the production of must and molasses.
In a doctoral thesis conducted at Mersin University (Yalım Kaya, 2010), particle size, water/fruit ratio, extraction temperature and time were optimized together for the production of high-purity sugar syrup from carob. This approach shows that extraction is not a single setting, but a balancing of variables that affect each other.
Ultrasound-Assisted Extraction
In ultrasound-assisted extraction, high-frequency sound waves applied to the liquid medium lead to the formation and collapse of small bubbles (cavitation). This effect can relax cell structures, accelerating the passage of soluble components into the liquid. The attractive aspect of the method for carob is that it can produce results in a short time at relatively low temperatures.
In Eroğlu's (2020) thesis, ultrasound-assisted extraction conditions were optimized by time, temperature, fruit/solvent ratio, and ultrasound power variables; the optimal conditions were determined as 40 °C, 21 minutes, 1:9 ratio, and 84 percent ultrasound power. When molasses produced from ultrasonic wort was compared with molasses produced from conventional wort, no significant differences were found in terms of chemical composition, color, antioxidant capacity, and total phenolic substances. HMF values were reported to be slightly higher in ultrasound application, but remained below acceptable limits. The author concluded that the method could reduce the traditional extraction from hours to about 21 minutes.
Antoniou et al. also state that ultrasound is an effective tool in sugar extraction, especially from powder-sized kibble. In another study (Ben Hamouda et al., 2025), maceration and ultrasound-assisted extraction were comparatively optimized based on variables such as ethanol concentration, temperature, duration, and ultrasound power to increase antioxidant yield.
Microwave and Supercritical Fluid Extraction
In microwave-assisted extraction, energy is transferred directly to the water in the solvent and feedstock; in this way, heating occurs quickly and the increase in intracellular pressure can facilitate the exit of components. In supercritical fluid extraction, carbon dioxide is generally used as a solvent in conditions above critical temperature and pressure.
A study involving researchers from Morocco, Italy, and Spain (Mansouri et al., 2022) compared four methods for obtaining phenolic compounds from carob fruit. The results are summarized in the table below:
| Method (Mansouri et al., 2022) | Total phenolics (mg GAE/g dry matter) |
|---|---|
| Microwave-assisted extraction | 34,35 |
| Supercritical fluid (CO₂) extraction | 28,38 |
| Ultrasound-assisted extraction | 20,38 |
| Soxhlet extraction | 11,55 |
In this study, microwave application was performed in a closed container at 100 °C, with a power of 400 W and with an acetone/water mixture. Total flavonoid and condensen tannin values were also found in the highest microwave extract. An important distinction should be noted here: Such studies are carried out on a laboratory scale and often with organic solvents for analysis or bioactive compound extraction. In the production of must or molasses, which is a food product, the solvent is water and the target is mostly sugar yield. Therefore, the fact that a method is "the best" in obtaining phenolics does not mean that it is the most suitable method for food production.
Purification and Enrichment: What Happens After Extraction?
The liquid obtained by extraction; In addition to sugars, it contains phenolics, minerals, proteins and suspended solid particles. Depending on the purpose of the product, this liquid is subjected to different processes:
- Filtration and clarification: Removal of suspended solids and turbidity substances
- Adsorbent application: Reduction of color and some phenolic compounds
- Membrane filtration: Separation of molecules based on their size
- Thickening: Increasing dry matter by removing water
In the thesis of Yalım Kaya (2010), it was reported that a syrup containing 73.62 percent sucrose, 14.58 percent glucose and 9.06 percent fructose with a total sugar of approximately 97.26 percent was obtained through clarification and purification steps. This example shows that a very different product from traditional molasses can be obtained from the same raw material depending on the post-extraction processes.
An example of enrichment is D-pinitol studies. Hacıoğlu et al. (2020) enriched D-pinitol from carob extract by extraction, clarification, adsorbent application and nanofiltration steps; reached the highest concentration of D-pinitol with a 5 kDa membrane, at a feed pressure of 3 bar and at 25 °C, obtaining 10.48 g/L D-pinitol in filtrate. For detailed information about D-pinitol What is D-Pinitol in Carob? You can take a look at our article.
Cold Extraction and "Carob Extract" Products
Some products sold in the market under the name "carob extract" state that they are produced by condensing the must obtained by cold extraction at low temperature. Yavuz Küçük and Duraklı Velioğlu (2022) compared these products with traditional carob molasses. The total phenolic substance was approximately 5.80–18.00 mg GAE/g in molasses samples and 0.10–18.40 mg GAE/g in extract samples; HMF was found to be approximately 0.79–50.25 mg/kg in molasses and 1.25–68.77 mg/kg in extracts. The researchers did not detect a statistically significant difference between the two groups in terms of measured properties and stated that the findings may shed light on future adjustments for this product group.
This result reminds us that the expression "cold" or "low temperature" alone does not guarantee product quality; the main determinant is raw material, process control and final product analysis. About the concepts of extract and extract What is Carob Extract? You can find more information in our article.
What to Look for When Choosing a Method
There is no single "best method" for carob extraction. The choice is based on the target crop:
| Objective | Featured approach | Point to note |
|---|---|---|
| Must and molasses | Aqueous extraction, ultrasound support if required | Sugar/phenolic balance, taste, HMF |
| Pure sugar syrup | Aqueous extraction + clarification and purification | Color, clarity, sugar purity |
| Phenolic/antioxidant extract | Microwave, supercritical, ultrasound (mostly with solvent mixtures) | Solver security, scalability |
| Specific ingredient (e.g., D-pinitol) | Extraction + membrane separation | Purity, yield, cost |
Reviews evaluating a combination of advanced extraction techniques used to extract bioactive components from natural sources (e.g., Bhadange et al., 2024) show that these methods are increasingly being investigated in different feedstocks. However, issues such as equipment investment, energy consumption, and large-scale transfer must be calculated separately for each business; it is not always easy to replicate good results obtained in the laboratory in the same way in industrial facilities.
Frequently Asked Questions
Why use water in carob extraction?
In food products such as must, molasses and syrup, the target is mostly water-soluble sugars. Water is a safe, cheap and food-grade solvent.
Does increasing the temperature always improve the extraction?
One study reported that an increase in temperature passes phenolics into more solution than sugars, which can shift the taste to astringency.
Does ultrasound ruin molasses quality?
In a thesis study examined, no significant difference was found between molasses produced from ultrasound-assisted must and traditional molasses in terms of composition, color and antioxidant capacity; Although HMF was slightly high, it remained below the limits.
Can the microwave method be used in food production?
In carob studies, microwave has been tried mostly for obtaining phenolic compounds and often with organic solvents. Its use on a food scale should be evaluated separately.
Carob Raw Material with Carob Türkiye
Whichever extraction method is chosen, the first factor that determines the result is the raw material. As studies have shown, the source of the raw material and the size of the kibble directly affect the yield of sugars and phenolics.
At Carob Türkiye, we supply carob fruit, crumbs, flour/powder, kernels, and extracts. Carob Kibble (Granular), Carob Extract and D-Pinitol Extract You can review our pages, where we explain molasses production. What is Carob Molasses and How is it Made? You can read our article. For your wholesale and export requests Contact Now You can contact us on our page.
Domestic resources
Eroğlu, Z., "Investigation of some quality properties of molasses obtained from carob by determining ultrasonically assisted extraction parameters", PhD Thesis, Munzur University Graduate Education Institute, 2020 (YÖK Thesis No: 628859). Tezara.
org/ theses/ 628859 Yalım Kaya, S., "Production of high purity sugar syrup from carob fruit", PhD Thesis, Mersin University Institute of Natural and Applied Sciences, 2010 (YÖK Thesis No: 283071). Tezara.
org/ theses/ 283071 Yavuz Küçük, A., Duraklı Velioğlu, S., "Determination of Some Chemical Properties of the Product Offered for Sale Under the Name of 'Carob Extract' and Comparison with Carob Molasses", Gıda, 47(5), 889–903, 2022. doi.
org/ 10. 15237/ food. GD22033 Hacıoğlu, A., Assoumou, U. T. Z., Yıldız, M., Arslan Kulcan, A., Yavuz, İ., Karhan, M., "Optimization of D-pinitol Enrichment from Carob (Keçiboynuzu) Extract by Nanofiltration Using Response Surface Methodology" (title of the article in English), Turkish Journal of Agriculture – Food Science and Technology, 8(9), 1846–1853, 2020. doi.
org/ 10. 24925/ turjaf. v8i9. 1846- 1853. 3429 Foreign sources
Antoniou, C., Kyratzis, A., Rouphael, Y., Stylianou, S., Kyriacou, M. C., "Heat- and Ultrasound-Assisted Aqueous Extraction of Soluble Carbohydrates and Phenolics from Carob Kibbles of Variable Size and Source Material", Foods, 9(10), 1364, 2020. doi.
org/ 10. 3390/ foods9101364 Mansouri, F. E., et al., "Evaluation of Different Extraction Methods on the Phenolic Profile and the Antioxidant Potential of Ceratonia siliqua L. Pods Extracts", Molecules, 27(19), 6163, 2022. doi.
org/ 10. 3390/ molecules27196163 Ben Hamouda, G., Bettaieb Rebey, I., Zar Kalai, F., Hammami, M., Ksouri, R., "Enhancing antioxidant yield from carob (Ceratonia siliqua L.): evaluating the efficacy of maceration and ultrasound-assisted methods", International Journal of Environmental Health Research, 35(7), 1793–1805, 2025. doi.
org/ 10. 1080/ 09603123. 2024. 2407456 Bhadange, Y. A., Carpenter, J., Saharan, V. K., "A Comprehensive Review on Advanced Extraction Techniques for Retrieving Bioactive Components from Natural Sources", ACS Omega, 9(29), 31274–31297, 2024. doi.
Scientific Resourcesorg/ 10. 1021/ acsomega. 4c02718
