What are the methods for extracting capsanthin?

What are the methods for extracting capsanthin? What are the advantages and disadvantages of each?

1. Oil dissolution method

The oil dissolution method is to soak pepper peel or dried pepper powder in liquid edible oil (such as cottonseed oil, soybean oil, rapeseed oil, etc.) at room temperature to dissolve the capsanthin in the edible oil, and then extract the capsanthin from the oil by a certain method [8]. Process flow: pepper → extraction → distillation → capsanthin oleoresin → hydrolysis → filtration → solid matter → soaking → vacuum filtration → extract → vacuum distillation → concentrated and refined pigment → drying → powdered capsanthin. When using the oil dissolution method to extract capsanthin, the separation of oil and pigment is difficult, resulting in a low extraction rate of capsanthin and difficulty in obtaining products with high color value. It has now been basically discontinued.

2. Solvent method

This is the conventional production method of capsanthin: after removing the bad peppers, stems and seeds, the dried peppers are ground into powder, extracted with organic solvents (such as acetone, ether, chloroform, trichloroethane, hexane, etc.), the extract is concentrated to obtain the primary capsanthin oleoresin, and the product is obtained by vacuum distillation [9]. Process flow: pepper powder → organic solvent extraction → vacuum recovery of solvent → oily red pigment → organic solvent extraction → vacuum recovery of solvent → product There are four methods for extracting capsanthin using organic solvents: immersion method, percolation method, reflux extraction method, and Soxhlet extraction method. At present, most manufacturers of capsanthin at home and abroad use solvent extraction. However, no matter which of the above extraction methods is used, the pepper powder needs to be ground into powder before extraction, which has high operating costs. In addition, since a considerable amount of red pigment remains in the residue after extraction [10], the impurity content of the obtained product is high, the refining cost is expensive, and the availability of the residue is poor, which brings difficulties to production. Wu Ming et al. mentioned a new process for extracting capsanthin by using the hot countercurrent method when discussing the new process for extracting natural capsanthin.[11] Process flow: dry pepper → remove seeds and chop → extract capsanthin → remove spiciness → extract red pigment → reduce pressure and concentrate → vacuum drying → red pigment ↓ deep processing of residue → by-product. Its advantages are mainly reflected in three aspects: 1) short extraction time, low solvent usage, high yield, and high color value; 2) the raw materials do not need to be crushed into powder before extraction, the operating cost is reduced, and the utilization value of the residue is high. A series of products with high added value have been developed. In addition, the disadvantage of leaching out some components with larger molecular weight due to excessive damage to the plant cell wall is avoided.[12] This process integrates filtration, extraction, and concentration, so the equipment investment and operating costs are relatively low; 3) the red pigment can be extracted by this process to obtain the finished product in one go, and the product does not need to be refined, and all indicators meet the relevant standards. In short, this process has a high application value. Since the equipment used is similar to the equipment currently used for extracting capsanthin by solvent method, it also provides an ideal way for manufacturers to transform their processes.

3. Supercritical CO2

Fluid Extraction Supercritical CO2 fluid extraction is an extraction process that uses CO2 fluid above the critical temperature and critical pressure as a solvent. Supercritical fluid extraction is a new type of chemical separation technology. The key is to understand the solubility of supercritical fluids and their changing rules under the influence of many factors. This technology is simple, energy-saving, non-toxic and easy to recycle. The resulting product has extremely high purity, and the residual solvent meets FAO/WHO requirements. The pigments obtained by the extraction method are mostly mixed pigments. The method is simple, the cost is relatively low, and the color value is high. It has become a common preparation process at home and abroad. This method is an advanced extraction method, but it needs to be further improved.