Study On Protein Extraction From Zophobas Morio

In this paper, the contents of general nutrients, amino acids, mineral and trace elements in differentinstars of zophobas morio were comprehensive analyzed. Zophobas morio protein was extracted from thefat-free pupae powder of zophobas morio with three kinds of extracting methods. They were methods ofalkali extracting, salt extracting and enzymatic hydrolysis. Took the protein extraction rate as an evaluationindex. on the basis of single factor test, optimized the extraction process using orthogonal test. And throughthe study of determining the isoelectric point of the protein, content of consisting of protein and removal ofthe nucleic acids with Dnase, trying to initially explored a reasonable way to extract and purify thezophobas morio protein, which will provide scientific basis for comprehensive utilization of zophobasmorio.The results showed that there was a moisture content range of58.67～62.05g/100g; and there was afatty content range of23.81～36.36g/100g; a protein content range of45.21～54.97g/100g in dry sample;they all comprised17kinds of amino acids (tryptophon not measured), in which there was a EAA range of39.63%～45.99%in total amino acid, the contents of EAA were all higher than beef and Erie whole milk,slightly lower than the eggs, the first limiting amino acid in different instars of zophobas morio is Met andCys, besides, the essential amino acid index (EAAI) ranges between92.84and110.84; the contents of P, Znand Fe was higher than those in general animal food, too; the optimum extraction conditions of protein inzophobas morio pupae with alkali method were: aqueous alkali concentration1.0g/100mL, solid-liquidratio1:10(g/mL), extracting temperature60℃, extracting time2.0h, the protein content was82.130%, andthe protein extraction rate was81.540%; the optimum extraction conditions of with salt method were: saltconcentration1.0g/100mL, solid-liquid ratio1:15(g/mL), extracting temperature50℃, extracting time2.0h, the protein content was75.010%, and the protein extraction rate was53.740%; through the screeningof5enzyme preparation, the optimum protease was Alcalase, the optimum process conditions withAlcalase were as follows: enzyme dosage (E/S)5.0%, enzymolysis pH12.0, material-water ratio1:20,enzymolysis temperature50℃and enzymolysis time2.5h, the protein content was76.220%, and theextraction rate of protein was86.960%; the isoelectric point of zophobas morio pupa protein (PI) was4.0;the content of four protein composition of zophobas morio pupa protein was determined, which werealbumin, globulin, gliadin, glutenin, albumin content was highest for32.740%; after the addition ofdeoxyribonuclease (Dnase), the protein content increased5.330percentage points with the enzymaticextraction method, alkali method and salt method were also increased by3.080and3.700percentagepoints.The results can be drawn that nutritional components of pupae was more reasonable than other instarsof zophobas morio; considering factors such as protein yield and quality, the ideal protein extractionmethod was the enzyme method; water-soluble protein is easily digested and absorbed by human andanimal body, and therefore zophobas morio pupae protein was a good quality protein; deoxyribonucleasecan achieve the purpose of preliminary purification of crude zophobas morio protein.