Case Study: High-Shear Emulsifier Application in Sesame Paste Production
In the food processing industry, the quality of sesame paste is directly determined by the fineness of particle dispersion, uniformity of material mixing, and stability of the final product. Traditional production methods often face challenges such as uneven particle size, easy stratification during storage, long processing cycles, and high energy consumption. This case study focuses on how a high-shear emulsifier optimized the sesame paste production process, solved existing technical bottlenecks, and improved overall production efficiency and product quality.
1. Background and Production Challenges
The production facility specializes in the processing of nut-based pastes, with sesame paste as one of its core products. Prior to the introduction of new equipment, the facility relied on conventional mixing and grinding equipment for sesame paste production. After long-term operation, several prominent problems emerged, affecting both product quality and production efficiency.
Firstly, the particle fineness failed to meet consistent standards. The conventional equipment could not fully break down the sesame particles, resulting in a grainy texture in the final product. Some batches even contained visible small particles, which affected the mouthfeel and market acceptance. Secondly, the emulsification effect was unsatisfactory. Due to insufficient mixing of oil and water phases in sesame paste, the product was prone to stratification after a period of storage, with oil separating from the paste and forming a layer on the surface, reducing product stability and shelf life.
Thirdly, the production cycle was excessively long. The traditional process required multiple rounds of grinding and mixing to approach the desired texture, with each batch taking approximately 4 hours to complete. This low efficiency limited the facility's capacity to meet market demand during peak seasons. Additionally, high energy consumption and maintenance costs became a burden. The conventional equipment required high horsepower to operate, and frequent wear of grinding components led to increased maintenance frequency and costs.
To address these issues, the facility sought a technical solution that could improve particle fineness, enhance emulsification stability, shorten production cycles, and reduce overall operational costs. After conducting process tests and equipment evaluations, a high-shear emulsifier with customized parameters was selected for the production line.
2. Equipment Selection and Technical Adaptation
Considering the characteristics of sesame paste—high viscosity (up to 45,000 mPas), high oil content, and the need for fine particle dispersion—the selected high-shear emulsifier was customized to match the production requirements. The core design features of the equipment are as follows:
The emulsifier adopts a dual-stage rotor-stator structure, with a maximum rotational speed of 12,000 rpm and a linear speed of 42 m/s, which is significantly higher than that of conventional mixing equipment. This structure generates strong shearing force, impact force, and centrifugal force in the narrow gap between the rotor and stator, enabling efficient crushing and dispersion of sesame particles. The gap between the rotor and stator can be infinitely adjusted within the range of 0.1-0.5 mm, allowing precise control of particle size according to product requirements.
In terms of material selection, all parts in contact with the product are made of 316L stainless steel, which undergoes electrolytic polishing treatment to ensure a smooth surface with a roughness Ra ≤ 0.8 μm. This design not only meets food hygiene standards but also prevents material adhesion and residue, reducing the risk of cross-contamination and facilitating cleaning. The equipment is also equipped with a jacketed temperature control system, which can regulate the processing temperature between 25-60℃ to avoid the denaturation of nutrients in sesame and ensure the stability of the product's color and flavor.
To adapt to the high viscosity of sesame paste, the emulsifier is configured with a frequency conversion speed regulation motor, which allows stepless adjustment of rotational speed according to the material state during different production stages. The modular structure design enables quick replacement of wearing parts, reducing maintenance time and costs. Additionally, the equipment integrates a vacuum system with a vacuum degree of up to -0.095 MPa, which effectively removes air bubbles generated during the mixing process, further improving the uniformity and stability of the sesame paste.
3. Implementation Process and Process Optimization
Before formal production, the technical team conducted small-batch pilot tests to optimize the process parameters of the emulsifier. The test focused on adjusting rotational speed, processing time, temperature, and rotor-stator gap to determine the optimal parameter combination for sesame paste production.
In the initial test phase, the team found that a rotational speed of 8,000 rpm, a processing time of 15 minutes, a temperature of 45℃, and a rotor-stator gap of 0.2 mm achieved the best results. Under these parameters, the sesame particles were fully crushed, and the oil and water phases were completely fused. Based on the pilot test results, the production line was adjusted and upgraded to integrate the emulsifier into the existing process flow.
The optimized production process is as follows: After roasting and cooling, the sesame seeds are first crushed into coarse powder by a grinder, then transferred to the high-shear emulsifier. The emulsifier operates under the preset parameters, and the material is circulated through the rotor-stator area multiple times to achieve full dispersion and emulsification. During the process, the temperature control system maintains the material temperature at a stable level, and the vacuum system removes air bubbles in real time. After emulsification, the sesame paste is directly discharged to the next stage for degassing and filling.
Compared with the traditional process, the optimized process reduces the number of processing steps by integrating grinding and emulsification functions. The technical team also adjusted the feeding speed to match the processing capacity of the emulsifier, ensuring continuous and stable production without material accumulation.
4. Application Results and Performance Improvements
After the high-shear emulsifier was put into formal operation, the production line achieved significant improvements in product quality, production efficiency, and operational costs. The specific results are reflected in the following aspects:
In terms of product quality, the particle fineness of the sesame paste was significantly improved. The average particle size was reduced from 50 μm to less than 2 μm, and the particle size distribution CV value was controlled within 5%, resulting in a smooth and delicate mouthfeel without graininess. The emulsification stability was greatly enhanced—after 6 months of sealed storage at room temperature, no stratification or oil separation occurred, and the product maintained consistent texture and flavor. The elimination of air bubbles also improved the appearance of the sesame paste, making it more uniform in color and luster.
In terms of production efficiency, the processing cycle per batch was shortened from 4 hours to 45 minutes, a reduction of 81.25%. The emulsifier's high throughput capacity enabled the facility to increase daily production from 8 tons to 25 tons, effectively meeting the increased market demand during peak periods. The automated control system of the equipment reduced manual intervention, minimizing human errors and improving production consistency. The operator only needs to set the parameters and monitor the operation process, reducing labor intensity.
In terms of operational costs, the energy consumption per ton of product decreased by 32% compared with the traditional process. The high efficiency of the emulsifier reduced the operating time of the equipment, while the frequency conversion motor adjusted energy consumption according to production needs. The maintenance cost was also reduced by 40%—the wear-resistant rotor-stator and modular design extended the service life of the core components, and the easy-to-clean structure reduced the time and cost of equipment cleaning and maintenance.
Furthermore, the equipment's compliance with food hygiene standards (EHEDG guidelines and 3A certification) ensured that the production process met relevant regulatory requirements, reducing the risk of quality inspections and product recalls. The stable product quality also improved customer satisfaction, with a noticeable reduction in feedback related to texture and stratification issues.
5. Summary and Experience
The application of the high-shear emulsifier in sesame paste production successfully solved the technical bottlenecks faced by the traditional process, achieving a win-win situation in product quality improvement and production efficiency enhancement. The key to this success lies in the precise matching between the equipment's technical characteristics and the production requirements of sesame paste— the high shear force, adjustable parameters, and vacuum function of the emulsifier effectively addressed the problems of uneven particle size, poor stability, and low efficiency.
For food processing enterprises engaged in high-viscosity paste products, selecting equipment that matches material characteristics and conducting sufficient pilot tests are crucial steps in process optimization. The modular and intelligent design of the emulsifier also provides flexibility for future production adjustments, allowing the facility to adapt to changes in product specifications and market demand by adjusting parameters or replacing components.
In the context of increasing consumer demand for product quality and rising production costs, the application of efficient and stable emulsification equipment has become an important way to improve the competitiveness of food processing enterprises. This case provides a practical reference for the optimization of sesame paste and similar nut-based paste production processes, demonstrating the significant value of advanced processing equipment in promoting industrial upgrading.
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