OBJETIVES: Modifications in the treatment of samples and operational sequence of the gravimetric non enzymatic method were carried out in order to simplify it and allow the quantification of soluble and insoluble quantities of the total dietary fiber. METHODS: Lyophilization influence was first evaluated in guava samples and afterward in samples of acerola, mango, sugar apples, sapodilla and grapes. The mentioned fruits and also pineapple, cashew, passion fruit and strawberry were tested for the modifications intrinsic in the methodological sequence. RESULTS: The average total dietary fiber for guava, both lyophilized and non-lyophilized, were: 10.50% ±0.97 and 10.53% ±0.88, respectively, revealing good method reproducibility and no significant differences among the treatments applied to guava and other fruits. Differently from what was found in the determination of the insoluble dietary fiber, which had a variation of 99.6% for cashew and 54.0% for acerola, the data generated for soluble dietary fiber were disregarded, due to the dispersiveness found. CONCLUSION: Those results show that the samples do not depend on lyophilization and that the quantification of soluble dietary fiber needs further adjustments of the precipitation stage.
dietary fiber; gravimetric non enzymatic method; fruits
