Dietary fibre analyser

Moisture content was determined by drying the samples at 105 °C to a constant weight (ICC 109/01). The ash content was determined gravimetrically as residue after combustion in a muffle furnace to 550 °C following AACC 08-01. Amino acid composition of wheat flour, microalgae and bread was estimated after hydrolysis in 6 M HCl for 22 h at 110 °C and analysed using HPLC and fluorescence detection [23 (link)]. The protein content of wheat flour, microalgae and bread are reported as the sum of all protein-bound amino acids. For protein digestibility determination [24 (link)] the protein content of the bread and digests was determined by combustion [25 (link)] using a Vario EL elemental analyser (Elementar, Langenselbold, Germany) with a nitrogen to protein conversion factor of 5.7 [26 (link)]. Free amino acids were determined by homogenizing the sample in an internal standard solution, derivatization with phenyl isothiocyanate, separation with reverse HPLC and detection by UV [27 ]. Crude fat content was estimated by a gravimetric method using solvent extraction [28 (link)]. The total dietary fibre (TDF) was measured gravimetrically following AOAC method 985.29 using an Ankom dietary fibre analyser. At least duplicate analyses were performed for all measurements.