. 2019 Aug 14;6:127. doi: 10.3389/fnut.2019.00127

Table 1.

Protein contents of preparative dietary fiber preparations in percent determined by different detection methods after Kjeldahl digestion.

	(1) Titration	(2) Cuvettes	(3) 24-Well plates	(4) Electrode
asparagus IDF	9.44 ± 0.15	9.12 ± 0.17	9.36 ± 0.70	9.26 ± 0.13
asparagus SDF	21.14 ± 0.06^ab	22.02 ± 0.10^a	19.77 ± 0.97^b	22.03 ± 0.34^a
wild rice IDF	50.22 ± 0.35	52.08 ± 1.63	51.36 ± 1.05	49.51 ± 0.69
wild rice SDF	23.01 ± 0.05^a	25.07 ± 0.46^b	23.06 ± 0.91^a	23.63 ± 0.45^ab
buckwheat IDF	21.72 ± 0.27	20.71 ± 0.43	21.07 ± 1.03	21.69 ± 0.49
buckwheat SDF	35.95 ± 0.30	37.64 ± 0.63	34.23 ± 1.96	35.95 ± 0.43
pear IDF	6.20 ± 0.05^a	5.39 ± 0.18^b	5.96 ± 0.25^ab	5.50 ± 0.25^ab
pear SDF	13.83 ± 0.03	12.45 ± 0.18	13.00 ± 1.12	13.03 ± 0.16
wheat IDF	14.54 ± 0.04	14.42 ± 0.20	13.75 ± 0.04	14.59 ± 0.46
wheat SDF	18.74 ± 0.08	19.16 ± 0.08	18.60 ± 0.90	18.30 ± 0.49

The tested methods comprise a (1) classical titration with diluted HCl after steam distillation, the spectrophotometric method according to Willis et al. (8) in (2) cuvettes or in (3) 24-well plates, and the determination using an (4) ammonia electrode. IDF, insoluble dietary fiber; SDF, soluble dietary fiber. The data was statistically analyzed for each sample individually using one-way ANOVA and Tukey's test (α = 0.01). Values of a specific sample with the same letter are in the same group.