title: [Determination of total protein content in soya-bean milk via visual moving reaction boundary titration].
abstract: A visual, rapid and accurate moving reaction boundary titration (MRBT) method was used for the determination of the total protein in soya-bean milk. During the process, moving reaction boundary (MRB) was formed by hydroxyl ions in the catholyte and soya-bean milk proteins immobilized in polyacrylamide gel (PAG), and an acid-base indicator was used to denote the boundary motion. The velocity of MRB has a relationship with protein concentration, which was used to obtain a standard curve. By paired t-test, there was no significant difference of the protein content between MRBT and Kjeldahl method at 95% confidence interval. The procedure of MRBT method required about 10 min, and it had linearity in the range of 2.0-14.0 g/L, low limit of detection (0.05 g/L), good precision (RSD of intra-day < 1.90% and inter-day < 4.39%), and high recoveries (97.41%-99.91%). In addition, non-protein nitrogen (NPN) such as melamine added into the soya-bean milk had weak influence on MRBT results.
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
authors.forename: Chengye
authors.initials: C
authors.lastname: Guo
authors.affiliation: School of Life Sciences and Biotechnology of Shanghai Jiao Tong University, State Key Laboratory of Microbial Metabolism, Shanghai 200240, China.
authors.forename: Houyu
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Life Sciences and Biotechnology of Shanghai Jiao Tong University, State Key Laboratory of Microbial Metabolism, Shanghai 200240, China.
authors.forename: Liuyin
authors.initials: L
authors.lastname: Fan
authors.affiliation: School of Life Sciences and Biotechnology of Shanghai Jiao Tong University, State Key Laboratory of Microbial Metabolism, Shanghai 200240, China.
authors.forename: Chengxi
authors.initials: C
authors.lastname: Cao
mesh_terms: D000143:Acids; D000468:Alkalies; D041942:Soy Milk / Q000737:chemistry*; D030262:Soybean Proteins / Q000032:analysis*
chemical_list: D000143:Acids; D000468:Alkalies; D030262:Soybean Proteins