Abstract In the production of gluten-free noodles by using a single screw extruder, cooking is done at two consecutive stages. Initially, the dough of gluten-free formula is steamed manually at certain times and temperatures. During extrusion, the pre-cooked dough is re-cooked inside the extruder barrel. The purpose of this study was to evaluate the properties of gluten-free noodle (color, texture profile) produced from different production batches (batch 1 to 6) of two different single screw extruders (A: capacity 24 kg/hr, B: capacity 12 kg/hr) by using a single factor completely random design. The results showed that steaming process in batch cause intermitten time for extrusion and affected some non-uniform properties of the gluten-free noodles produced by the two extruders. The two extruders produced noodles with distinctive properties. The noodles from extruder A exhibited the hardness (average 26,925.14 ± 2,355.74gf) and adhesiveness (-7.66 ± 6.41 gs). The noodles of extruder B showed the elongation (157.91 ± 39.67%) and cohesiveness (0.91 ± 0.02).

Abstract The presence of calcium oxalate is the major obstacle in flour processing of Amorphophallus muelleri tuber since the calcium oxalate can induce skin irritation and is harmful to kidneys. The development of a rapid analytical method to detect calcium oxalate in Amorphophallus flour is required. This research was intended to evaluate the use of some analytical methods (FTIR, SEM-EDS, XRD, XRF, and titration methods) in calcium oxalate detection in Amorphophallus muelleri flour prepared from different treatments (soaking in water (W), solution of sodium bisulfite 1000 ppm (B), solution of sodium chloride salt 3% (S), solution of sodium bisulfite 1000 ppm and sodium chloride salt 3% (BS)). Results showed that the presence of oxalate in Amorphophallus flour can be detected in the FTIR spectra from the C=O group at a wavenumber of 1610 cm-1. SEM images confirmed that calcium oxalate in Amorphophallus flour existed as raphide crystals in which their quantity can be estimated by the EDS feature of SEM. The presence of calcium oxalate crystals in Amorphophallus flour can be differentiated from other salts present in the flour by XRD. XRF can be used as a rapid analytical tool to detect the presence of calcium oxalate in Amorphophallus flour. The potassium permanganate titration technique can be used as a reference method for other rapid analytical methods in detecting calcium oxalate in Amorphophallus flour.