To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the...To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the most suitable enzyme for hydrolyzing the flesh residue to release calcium-binding peptides among the seven tested proteases. The pepsin hydrolyzate (PHM) was divided into three fractions according to the molecule weight of its composition, which ranged from 0.5 to 15 kDa. The low-molecule-weight fraction named PHM-3 had the highest capability in combining calcium. The peptides existing in the PHM-3 fraction consisted of higher contents of Glu, Ala and Leu, and could produce one type of calcium-peptide complex by powerfully chelating calcium ions. PHM-3 products could effectively increase calcium absorption and retention while they decreased the calcium excretion in animal tests. Additionally, symptoms caused by low calcium bioavailability in ovariectomized rats, such as bone mineral density reduction and mechanical strength loss could be significantly ameliorated by the hydrolytic products addition in diet.展开更多
An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentat...An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.展开更多
基金supported by the National Natural Science Foundation of China (No.30900293)the Open Project Program of National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine (No.2011ZYX5-004),which is a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,PAPD(ysxk-2010)
文摘To prepare calcium-binding peptides, the flesh residue of Mactra Veneriformis was subjected to enzymatic hydrolysis. By comparing the capability of combining calcium of the hydrolyzates, pepsin was confirmed to be the most suitable enzyme for hydrolyzing the flesh residue to release calcium-binding peptides among the seven tested proteases. The pepsin hydrolyzate (PHM) was divided into three fractions according to the molecule weight of its composition, which ranged from 0.5 to 15 kDa. The low-molecule-weight fraction named PHM-3 had the highest capability in combining calcium. The peptides existing in the PHM-3 fraction consisted of higher contents of Glu, Ala and Leu, and could produce one type of calcium-peptide complex by powerfully chelating calcium ions. PHM-3 products could effectively increase calcium absorption and retention while they decreased the calcium excretion in animal tests. Additionally, symptoms caused by low calcium bioavailability in ovariectomized rats, such as bone mineral density reduction and mechanical strength loss could be significantly ameliorated by the hydrolytic products addition in diet.
基金the National Natural Science Foundatioo of China(No.30670566)the International S&T Cooperation Program of China(No.2006DFA33150)
文摘An improved process of hydrolysis of corn starch was adopted in the production of itaconic acid （IA）, the aim was to decrease the unfermentable reducing sugar （RS） in the medium from the beginning of the fermentation and to increase the crystallization efficiency of IA from the fermentation broth. The glucose （GS） syrups saccharified by several combinations of glucoamylase and pullulanase were investigated and used as the carbohydrate source of the fermentation medium for the spore-initiated submerged fermentations experiments. Compared with the conventional process （with pullulanase controlled）, the improved process decreased th.e RS residue in the fermentation broth from 3.01g/L to 1.35g/L and from 4.25g/L to 3.25g/L when the original RS of the medium were 100 and 120g/L, respectively. The crystallization efficiency of IA increased from 65% to 78.8% and from 69.58% to 82.81% with the original RS being 100 and 120g/L, respectively.
