[Analysis of soluble Ca content in banana pulp based on pretreatment of digestion model in vitro].

In the present paper, soluble Ca content in banana pulp was analyzed with pretreatment of digestion model in vitro. All the samples were digested by strong acid (perchloric acid and nitric acid with 1 : 4 ratio) and determined by AA700 flame atomic absorption spectrophotometry (FAAS). Meanwhile, the reproducibility of the analytical method was investigated. The results showed that (1) Content of Ca was 1.479 mg x g(-1) x DW in eighty percent maturity banana pulp. And the relative standard deviation was 4.12%. (2) Contents of Ca in the soluble and insoluble fractions were 1.108 and 0.412 mg x g(-1) x DW, respectively in eighty percent maturity banana pulp with pretreatment of digestion model in vitro. The extraction rate was 74.9% and the residue rate was 27.8%. (3) The relative standard deviations of the analytical results of Ca contents in those two fractions were 2.56% and 9.10%, respectively, in the reproducibility tests. It was showed that the digestion model in vitro did not affect the reproduction quality significantly. Moreover, the deviation between the theoretical value and the summation value of the extraction and the residue rates was only 2.7%, which showed good availability of the digestion model in vitro to be used as a pretreatment method in mineral element analysis process. (4) Relative standard deviation and recovery yield in the determination procedure were 0.11% (n = 9) and 99.2%, respectively.