Extraction & Concentration Technology Guide | Principles, Equipment & Quality Control

Concentrated fruit juice, dashi (stock) extract, tea catechin extract — extraction and concentration technologies that isolate target components from raw materials and condense them are the foundation for creating high-value-added food ingredients. This article compiles the essential knowledge for anyone looking to commercialize functional ingredients or concentrated raw materials through OEM manufacturing in Japan.

Extraction is the technology of dissolving target components from solid raw materials into a solvent to separate and recover them. In the food industry, it is widely used for obtaining plant extracts, fruit juices, dashi (stock), and functional ingredients. Extraction efficiency is determined by solvent type, temperature, time, raw material particle size, and solid-to-liquid ratio, and selecting the optimal extraction method based on the target component's characteristics is what determines quality and cost.

Hot Water Extraction

This is the most fundamental method, using water as the solvent under heated conditions (60–100°C) to extract water-soluble components from raw materials. It is broadly used for producing dashi (stock from bonito flakes, kelp, and shiitake mushrooms), tea (green tea, black tea, herbal tea), and plant extracts (licorice, ginger). Temperature and time settings critically affect quality. For example, for bonito dashi, 85–90°C for 2–3 minutes of short extraction is considered the optimal condition for maximizing umami components (inosinic acid) while suppressing off-flavors. For green tea, selective extraction by temperature is possible — low temperatures (60–70°C) prioritize theanine (umami) extraction, while higher temperatures (80–90°C) increase catechin (astringency/functional component) extraction rates. Equipment typically consists of batch extraction tanks (with agitators), while counter-current continuous extractors are used for large-scale production.

Ethanol Extraction

This method uses ethanol (food additive grade) as the solvent to efficiently recover lipophilic components and polyphenols that are difficult to extract with water alone. Ethanol concentration is adjusted within the range of 30–95%, with different concentrations extracting different components. Low concentrations (30–50%) extract sugars and saponins, while high concentrations (70–95%) preferentially extract fat-soluble vitamins, flavonoids, and terpenes. It is widely used for manufacturing functional ingredients such as propolis extract, turmeric extract, and grape seed extract. After extraction, ethanol is typically recovered and recycled by vacuum distillation, and residual ethanol in the final product is managed in accordance with Japan's Food Sanitation Act.

Supercritical CO2 Extraction

This advanced technology uses CO2 in a supercritical state (above its critical point: temperature 31.1°C, pressure 7.38 MPa), leveraging its intermediate solubility characteristics between liquid and gas. Supercritical CO2 is non-toxic, non-flammable, and leaves no residue — after extraction, simply reducing pressure converts the CO2 back to gas, which is completely removed, eliminating any concern about solvent residues. It is commercially used for coffee decaffeination, hop extract production, and oleoresin extraction from spices. By precisely controlling pressure and temperature, selective extraction of specific components is possible. Equipment requires high-pressure capability, resulting in significant capital investment (tens of millions to hundreds of millions of yen / several hundred thousand to several million USD), and processing costs are 3–10x higher than other extraction methods. However, it produces high-quality, organic-solvent-free extracts suitable for premium products.

Enzyme-Assisted Extraction

This method uses food-grade enzymes such as cellulase, pectinase, and protease to break down raw material cell walls, enhancing the extraction efficiency of internal components. Compared to conventional hot water extraction, it can operate at lower temperatures (40–60°C), offering superior preservation of heat-sensitive components. Applications include improving juice yield (pre-pressing treatment for apples and grapes), extracting plant-derived polysaccharides (beta-glucan, fucoidan), and manufacturing seaweed extracts. Optimizing enzyme type and dosage, reaction temperature, pH, and reaction time is the key to quality.

Concentration is the process of removing water from extracted liquids or juices to increase solids concentration (Brix value). It is performed to reduce transport costs, improve shelf life, and optimize for downstream processes (spray drying, filling). Since the degree of flavor, color, and nutrient preservation varies significantly by concentration method, selecting the optimal method for the product characteristics is critical.

Vacuum Concentration (Vacuum Evaporation)

This is the most common concentration method, using reduced pressure to lower the liquid's boiling point and evaporate moisture at low temperatures. Operating pressure is 5–50 kPa (absolute), which lowers the boiling point to 40–70°C. Compared to atmospheric evaporation, thermal quality degradation is significantly reduced, and this method is used for a wide range of food liquids including fruit juice, dashi, soup stock, and plant extracts. Multi-effect evaporators — multiple evaporation stages arranged in series to improve thermal efficiency — are the mainstream equipment, reducing energy costs by 1/3 to 1/7 compared to single-stage systems. Plate evaporators maximize evaporation surface area through thin-film formation while reducing residence time.

The concentration ratio is determined by the original Brix value and the target Brix value. For fruit juice, the standard is to concentrate from an original Brix of 10–15 to Brix 65–72. However, above Brix 40, viscosity increases sharply and evaporation efficiency drops, requiring forced-circulation evaporators or falling-film evaporators for high-viscosity liquids. Aroma compounds tend to volatilize early in the evaporation process, so aroma recovery units (devices that cool vapor to condense and recover aroma compounds) are commonly installed alongside the concentrator in fruit juice production, with recovered aromas re-added to the concentrate.

Membrane Concentration

This non-thermal concentration technology uses semipermeable membranes to selectively remove only water molecules. Because no heating is involved, loss of heat-sensitive components is virtually zero, providing excellent preservation of aroma compounds, vitamins, and enzyme activity. Primarily reverse osmosis (RO) and nanofiltration (NF) membranes are used.

• Reverse Osmosis (RO): Pore size 0.1–1 nm. Allows only water molecules to pass through while retaining virtually all solutes (sugars, salts, amino acids). Operating pressure is 2–8 MPa. Used for pre-concentration of fruit juice (Brix 10 → approximately 25). High-Brix concentration becomes difficult due to osmotic pressure increases, making Brix 25–30 the practical upper limit.
• Nanofiltration (NF): Pore size 1–10 nm. Retains divalent ions and molecules with molecular weight above 200 while allowing monovalent ions and small molecules to pass. Used for desalination and concentration of whey, and for selective separation of specific components.

The main drawback of membrane concentration is the decrease in permeate flux due to membrane fouling. Regular cleaning (alternating alkaline and acid cleaning cycles) and membrane replacement affect operating costs. Membrane lifespan typically ranges from 2–5 years depending on usage conditions.

Freeze Concentration

This technology partially freezes a liquid and separates the formed ice crystals to concentrate the remaining liquid. Because the operating temperature is -5 to -15°C, thermal quality degradation is completely avoided, yielding the highest-quality concentrate possible. It is used for premium products where flavor preservation is paramount, such as premium coffee concentrate, high-end fruit juice, and Japanese sake concentration. The drawbacks are slow concentration speed (several hours to over ten hours for batch processing) and high equipment and energy costs. The concentration ratio also has an upper limit of approximately Brix 40–50, which is lower than what vacuum concentration can achieve. Recent technological developments in progressive freeze concentration (continuously growing ice on a cooled surface) and suspension crystallization (generating and separating fine ice crystals) are improving efficiency.

Extraction and concentration technologies are utilized as indispensable foundation technologies across various sectors of the food industry. Below are representative applications and their technical highlights.

Fruit Juice Concentration

Concentrating pressed juice from oranges, apples, grapes, and other fruits to produce concentrated reconstituted juice (also known as "from concentrate" juice) is the largest-scale application of extraction and concentration technology. Pressed juice (Brix 10–15) is vacuum-concentrated to Brix 65–72, then stored and transported under refrigeration or frozen. At the point of use, water is added to restore the original Brix value (reconstitution). To compensate for aroma loss during concentration, aroma recovery processing — re-adding recovered aroma compounds to the concentrate — is the standard quality preservation technique. In recent years, a hybrid approach using membrane concentration for pre-concentration (to approximately Brix 25) followed by vacuum concentration to the final target concentration has become widespread. This rational approach preserves aroma compounds through the low-temperature membrane step while leveraging the high concentration ratios achievable with vacuum concentration.

Plant Extracts (Functional Ingredients)

Manufacturing plant extracts containing functional ingredients — such as polyphenols (green tea catechins, grape seed proanthocyanidins), carotenoids (lutein, astaxanthin), and flavonoids (isoflavones, hesperidin) — has seen rapidly growing demand alongside the expansion of the health food and supplement market. The typical process is: raw material pre-processing (washing, drying, milling) → extraction (hot water or ethanol) → solid-liquid separation (filtration, centrifugation) → concentration (vacuum concentration) → drying (spray drying) → powdering. To increase functional ingredient content, additional purification steps such as HP-20 column chromatography or ultrafiltration membrane processing may be added. Optimizing extraction conditions to balance target component purity and yield is the core of formulation design.

Dashi (Stock) & Soup Stock

Extraction and concentration technologies are also used in producing traditional Japanese dashi (bonito, kelp, dried sardine) and Western soup stocks (chicken broth, beef broth). For dashi, the raw material quality (grade of bonito flakes, origin and grade of kelp) combined with extraction conditions (temperature, time, solid-to-liquid ratio) determines the final flavor profile. Commercial concentrated dashi is vacuum-concentrated to Brix 20–40 after extraction, and distributed at room temperature or refrigerated. In recent years, enzyme-assisted extraction has also become popular as a technique to more efficiently extract umami components from within the cells of bonito flakes and shiitake mushrooms.

High-Purity Extraction of Functional Ingredients

For applications requiring high-purity extraction of specific functional ingredients, processes combining multiple extraction and purification technologies are designed. For example, for high-catechin-content extract from green tea, a three-stage process of hot water extraction → ethyl acetate partitioning → column chromatography produces an extract with catechin purity of 80% or higher. Supercritical CO2 extraction is particularly effective for selective separation of specific components such as caffeine removal (decaffeination) and astaxanthin extraction. These advanced purification processes require significant capital investment and operating costs, so they are typically adopted only for the production of high-value functional ingredients and supplement raw materials.

Extraction and concentration processes require precise process control to efficiently recover target components from raw materials while maintaining quality. Below are the major control items that affect quality.

Optimizing Extraction Conditions | Temperature, Time & Solvent Ratio

To balance extraction efficiency and quality, the three elements of temperature, time, and solid-to-liquid ratio (ratio of solvent volume to raw material weight) must be optimized. Generally, raising the temperature improves extraction speed, but simultaneously increases extraction of unwanted components (astringency, bitterness, coloring agents) and accelerates degradation of heat-sensitive components. For example, for green tea catechin extraction, the standard conditions are 80°C for 5 minutes, but low-temperature, long-duration extraction below 70°C may be chosen to suppress degradation of epigallocatechin gallate (EGCG). The solid-to-liquid ratio is typically set between 1:5 and 1:20 (5–20 L of solvent per 1 kg of raw material) — higher ratios improve extraction yield but increase the concentration load downstream. Multi-stage extraction (extracting from the same raw material with fresh solvent multiple times) is effective for improving yield, but involves trade-offs with processing time and cost.

Brix Management and Concentration Ratio Control

Brix value (soluble solids concentration as indicated by a refractometer) is the most fundamental inline control metric for the concentration process. Standard practice involves installing inline refractometers for real-time Brix monitoring, with automatic controls that terminate concentration when the target value is reached. Since Brix value represents the apparent solids concentration, including not only sugars but also amino acids, organic acids, and salts, some products require concurrent HPLC (High-Performance Liquid Chromatography) analysis for quantifying individual components. Excessive concentration can trigger Maillard reactions (browning) or caramelization, so setting upper limits for temperature and concentration degree is particularly important for products where sugars and amino acids coexist (fruit juice, dashi).

Color and Aroma Preservation

The color of extracted liquids directly influences consumer quality perception, so quantitative control using colorimeters (Lab values) is practiced. For fruit juice, specifications are set for L value (lightness), a value (red-green), and b value (yellow-blue), with numerical monitoring of browning progression. Since aroma compounds are highly volatile, their loss during the concentration process is a quality challenge. In addition to the aroma recovery technology described earlier, approaches such as the hybrid method combining membrane concentration → vacuum concentration for aroma preservation, and microencapsulation for stabilizing aroma compounds, have been commercialized.

Microbiological Control and Hygiene Measures

Extracted liquids are rich in nutrients and have high water activity, making them high-risk intermediate products for microbial contamination. The fundamental principle is to promptly proceed with concentration or sterilization after extraction to reduce the product's water activity. Extraction equipment and tanks are cleaned with CIP (Clean-in-Place) systems after every batch or daily to prevent microbial contamination of product-contact surfaces. Cold storage at 5°C or below or frozen storage at -18°C or below is recommended for concentrates. When ambient-temperature storage is required, microbial control through high concentration to Brix 65 or above, or pH adjustment (pH 4.0 or below), is necessary. Testing for total viable count, coliforms, and fungi (yeast and mold) is conducted as both in-process control and shipping inspection.

Residual Solvent Management (for Ethanol Extraction)

For products made using ethanol extraction, management of residual ethanol concentration in the final product is required. Japan's Food Sanitation Act does not specify explicit limits for residual solvents, but products with less than 1% alcohol content are not classified as alcoholic beverages under Japan's Liquor Tax Act. For supplements and health foods, many manufacturers set an internal quality standard of 0.5% or less residual ethanol, managed through quantitative analysis by gas chromatography (GC).

When outsourcing extraction and concentration to an OEM manufacturer, it is important to confirm in advance the available extraction methods, equipment scale, quality control systems, and regulatory compliance capabilities. Below are the main items to verify and cost guidelines.

Equipment Capabilities and Compatibility

Extraction and concentration equipment varies widely among manufacturers in terms of available methods and scale. Equipment information to verify when selecting a manufacturer includes:

• Extraction equipment: Batch extraction tank capacity (100 L–10,000 L), agitation method, temperature control range, ethanol extraction capability (explosion-proof requirements), availability of supercritical CO2 extraction units
• Solid-liquid separation equipment: Availability of filter presses, centrifuges, and microfiltration (MF) membranes. Separation efficiency directly affects extract clarity and yield.
• Concentration equipment: Vacuum evaporator type (multi-effect, thin-film, plate) and throughput, availability of membrane concentration systems (RO/NF), availability of aroma recovery units
• Downstream equipment: Spray dryers, freeze dryers (needed for extract powdering), filling machines (needed for liquid concentrate filling)

Scale-Up from Lab Scale

Extraction and concentration processes are prone to quality variation during scale-up from lab scale (hundreds of mL to several L) to commercial scale (hundreds of L to thousands of L). In particular, agitation efficiency, temperature distribution uniformity, and solid-liquid separation efficiency change significantly with scale. A reliable OEM manufacturer should offer pilot-scale (50–200 L) confirmation batches. Proceeding directly to production with only lab data risks yield decreases and quality variation, so always conduct scale-up testing. Pilot prototyping costs are approximately ¥100,000–300,000 (about $700–$2,100 USD) per run.

Regulatory Compliance (Japan's Food Sanitation Act)

Manufacturing extraction and concentration products requires compliance with the following regulations under Japan's Food Sanitation Act.

• Food manufacturing business license: Manufacturing extraction/concentration liquids requires business licenses such as soft beverage manufacturing, food manufacturing (prepared foods, canned/bottled food manufacturing, etc.). Verify that the OEM manufacturer holds the appropriate licenses.
• Food additive usage standards: Confirm that ethanol used as an extraction solvent is food additive grade, and that enzymes used for enzymatic extraction are approved Japanese food additives.
• Residual solvent standards: When hexane (for oil extraction) is used, residual limits are established. While hexane extraction is common in edible oil manufacturing, residual hexane in the final product must be removed to undetectable levels.
• Foods with Function Claims filing: When an extract is used as the functional ingredient, the filing requires standardization of extraction conditions, establishment of ingredient specifications, and validation of analytical methods.

Cost Estimates

• Hot water extraction + vacuum concentration (liquid extract): Processing fee ¥300–1,000/kg (approx. $2–$7 USD/kg, concentrate basis). Minimum lot: 100–300 kg raw material.
• Ethanol extraction + concentration + drying (powdered extract): Processing fee ¥1,500–5,000/kg (approx. $10.50–$35 USD/kg, powder basis). Minimum lot: 100–500 kg raw material. Includes solvent recovery costs.
• Supercritical CO2 extraction: Processing fee ¥5,000–20,000/kg (approx. $35–$140 USD/kg, extract basis). Minimum lot: 50–100 kg raw material. Limited number of capable manufacturers due to equipment rarity.
• Membrane concentration (fruit juice, etc.): Processing fee ¥50–200/L (approx. $0.35–$1.40 USD/L, concentrate basis). Cost-effective at large volumes (several tons or more per batch).

Lead Time and Development Flow

Developing extraction and concentration products through OEM takes time for raw material selection and extraction condition optimization, so plan for 4–8 months from development start to first production batch. The standard development flow is: lab prototyping (1–2 months) → pilot prototyping (1–2 months) → quality specification finalization (1 month) → production preparation and raw material procurement (1–2 months) → production (2–4 weeks). For OEM manufacturing of standard extract products (green tea extract, turmeric extract, etc.) with already-optimized extraction conditions, lead time can be shortened.

Extraction and concentration technology is a process that requires many technical decisions, from raw material selection to extraction method choice and concentration condition optimization. Quality variation during scale-up is particularly significant for this process, so proceeding to production only after verification through pilot prototyping is a prerequisite for success.

This technology is ideal when you want to:

• Commercialize plant-derived functional extracts (catechins, polyphenols, etc.) as raw materials
• Sell concentrated fruit juice or dashi concentrate as commercial ingredients or retail products
• Use organic-solvent-free, high-quality extracts (supercritical CO2 extraction) as a product differentiator
• Incorporate high-value-added concentrated ingredients into existing food and beverage products

Key questions to ask OEM manufacturers:

• Do they support your required extraction method (hot water, ethanol, supercritical CO2, enzyme-assisted)?
• Can they conduct pilot-scale scale-up testing?
• Can they handle downstream processes (spray drying, freeze drying, filling) as part of an integrated service?
• Do they have aroma recovery or other flavor preservation equipment?
• Do they hold the required food manufacturing business licenses and HACCP certification?

Our platform makes it easy to search and compare OEM manufacturers in Japan that offer extraction and concentration services. Start by checking the detail pages of manufacturers that interest you and reach out for a free consultation.