A kind of pretreatment method of purple sweet potato pigment extract

Abstract

The invention belongs to the technical field of food processing, and relates to a pretreatment method of a purple sweet potato pigment extract solution. The preparation method comprises the following preparation processes: cleaning a purple sweet potato root tuber, cutting into slices and then cutting into shreds; adding 1.0-2.5% of (mass-to-volume ratio, w / v%) calcium chloride water solution to soak and extract; adjusting the pH value of the extract solution to 1.5-2.5; soaking and extracting for 2-6 hours; filtering or centrifuging the extract solution, and then adding a tannic acid aqueous solution while controlling the adding amount of tannic acid being 0.02-0.03% (mass-to-volume ratio, w / v%); evenly mixing and standing for 2-4 hours; separating and removing solid sediments, so as to obtain clear and stable pigment extract solution. The method has the characteristics that the light transmittance of the extract solution at 660nm can be improved by 6-10 times by adopting the composite adding precipitation method of calcium chloride and tannic acid; the clarification effect is significant; the dosage of concentrated hydrochloric acid or concentrated sulfuric acid for adjusting the pH value can be reduced by over 20% by adding calcium chloride in extraction. Therefore, corrosion on equipment caused by acid is also reduced.

Description

Technical field [0001] The invention relates to a pretreatment method for a purple sweet potato pigment extract, which belongs to the technical field of food processing, in particular adding calcium chloride when extracting pigments to reduce the precipitation of starch impurities and reduce the amount of acid used for pH adjustment; After finishing, add tannic acid, combine with protein, polysaccharide and calcium ion in the solution, play a role of co-precipitation, remove impurities that easily cause precipitation, and obtain a clear and stable solution to facilitate subsequent resin adsorption and purification operations of the pigment solution . Background technique [0002] Purple sweet potato pigment is a natural product extracted from the root tuber of Ipomoea batatas (Ipomoea batatas). The main component is cornflower 3-glucoside anthocyanin. As a kind of natural food coloring, purple sweet potato pigment is not only safe and non-toxic, but also has high nutritional val...

AI Technical Summary

Problems solved by technology

[0004] (1) The method of multi-stage natural sedimentation is time-consuming, low in production efficiency, and the stability of natural pigments is poor and easy to be oxidized, which will lead to a certain loss of pigments

[0005] (2) The method of filtration is adopted, the operation time is short, but the treatment is not thorough. Some macromolecular substances in the solution such as starch, protein and cellulose will aggregate with time, and precipitate slowly, which will be absorbed by the subsequent column. operation causing blockage