Study On Extraction And Quality Control Of Almond Dregs Protein

Almond protein is rich in many nutrient value and economy value, also is an underutilized protein source. In this paper, almond dregs was taken as the experimental material, and the ultrasound-assisted extraction and enzyme extraction technology of almond dregs protein were researched. The performance and composition of almond protein from almond dregs were analyzed, and finally the general quality control system of almond protein extraction was established. The main results were as follows:1. The method of alkali fusion and acid precipitation is convenient, rapid, simple and easy to be applied. In order to improving the efficiency of almond protein extraction, the ultrasound-assisted extraction were used. On the basis of single factor test, the optimization of maximum effciency of protein extraction was investigated using response surface methodology with three variables including extraction temperature, pH and ratio of solid to liquid. The regression equation was acquired: Y=68.753+4.85X₁+2.30X₂-0.44X₃-3.10X₁X₂-0.75X₁X₃+0.89X₂X₃-5.49X₁²-5.77X₂²-6.61X₃². The results showed that the optimized parameters of the almond dregs protein extraction process were as follows: extracting temperature 37°C, pH 10.1, and ratio of solid to liquid 1∶29.5. The effciency of protein extraction was 69.76%with twice extraction for each 30 min under the above conditions.2. Extracted almond dregs protein by enzyme is mild reaetion condition and substrate specialization. In order to improving the efficiency of almond protein extraction, the Alcalase and Protamex were used. The effciency of protein extraction is first parameter for the ratio of two proteases. On the basis of single factor test, the optimization of maximum effciency of protein extraction was investigated using response surface methodology with three variables including enzyme, pH and ratio of solid to liquid. The regression equation was acquired: Y=59.06+2.88X₁+2.81X₂+2.71X₃+0.77X₁X₂-0.39X₁X₃-1.56X₂X₃-5.17X₁²-5.98X₂²-1.52X₃². The results showed that the optimized parameters of the almond dregs protein extraction process were as follows: the ratio of Alcalase to Protamex, enzyme concentration, solid-liquid ratio, temperature, pH and extraction time were shown to be2:1, 4.3%, 1:30 , 41℃, 8.8 and 3hour, respectively, under which the effciency of protein extraction was up to 61.12%.3. The SDS-PAGE method has been applied to analyse the compositions of the extracted almond protein and the results showed the existence of at least three different types of molecules in almond protein. Water absoprtion and oil bsoprtion of almond protein were tested and were compared to soybean portein.The results were that water absoprtion and oil absoprtion of almond protein were higher than soybean protein.4. In this paper, the hazard of the almond protein extraction was analyzed. The critical control points in almond protein extraction had been confirmed as material check, alkaline extraction and acid precipitation. The general control system was designed and constructed for the factories making almond protein by ultrasound-assisted extraction.