This study aimed to analyse the physicochemical, structural, functional, and thermal properties of flour from two indigenous Ethiopian Potato (Plectranthus edulis) varieties, Chanqua and Loffo, and to compare with wheat flour (WF). The study also investigated how oven and sun drying methods affected the physicochemical properties of the flours. The results demonstrated a significant distinction (p ≤ 0.05) between the flour samples and WF, attributable to variations in both the varieties and the drying methods except that no significant difference in pH was observed due to the varieties, and the fibre and ash content did not vary significantly with the drying methods. The moisture content (MC) of the flours ranged from 5.72 % in oven-dried Chanqua Ethiopian potato flour (OD-CEPF) to 7.53 % in sun-dried Loffo Ethiopian potato flour (SD-LEPF), both of which were lower compared to WF. The protein content varied from 4.47 % (SD-CEPF) to 5.93 % (OD-LEPF). FTIR tests revealed a significant impact on the structural changes, leading to variations in the location and intensity of infrared absorption peaks, particularly in sensitive regions. Whereas, the XRD patterns showed characteristic B-type diffraction, with a relative crystallinity (RC) of 31.97 % in CEPF and 30.53 % in LEPF having a significant difference (p ≤ 0.05) between them. LEPF had better flow properties than CEPF, with lower Hausner ratio (HR) (1.16 vs. 1.25), Carr's index (CI) (14.51 % vs. 20.26 %), and angle of repose (31.00° vs. 34.67°). It also showed significantly higher (p ≤ 0.05) water absorption capacity (WAC), oil absorption capacity (OAC) and swelling power (SP) properties than CEPF. The study also indicated notable distinctions in the thermal and paring properties of flours. The oven drying method was found to be superior in enhancing the physicochemical properties, with LEPF showing better physicochemical, functional, structural, and thermal properties than CEPF.

The Ethiopian potato (Plectranthus edulis) is an annual tuber crop indigenous to Ethiopia. The crop is underutilized and not much studied despite its high yield of starch, which has a good potential to contribute to the effort in meeting the quickly growing demand for starch. In this study, the effects of the ecotype and isolation methods on the physicochemical, functional, structural, and crystalline properties of starches were evaluated. Starches were isolated from two Ethiopian potato ecotypes (Loffo and Chanqua) using distilled water (DW), 0.01% sodium metabisulphite (SMS), and 1M sodium chloride (NaCl) in the isolation media. The results showed that the lowest starch yield was obtained from Chanqua using DW (97.4%), while the maximum was from Loffo using SMS (99.3%). The L* (lightness) and whiteness values of the starches obtained from Loffo were higher than those of Chanqua starches, with NaCl and SMS extractants yielding the highest values. The bulk density, water activity (a_w), pH, proximate composition (moisture content, protein, ash, fat, crude fiber, and carbohydrate contents), and techno-functional properties were established. The majority of these parameters varied depending on both the isolation method and the ecotype. The crystallinity pattern of all starches showed B-type diffraction, with differences in diffraction peak intensities between all starches. FTIR tests showed structural changes as a function of the ecotype and isolation procedure used. The Loffo ecotype exhibited considerably better results, and the SMS isolation method was found to be the most effective way to acquire the highest starch quality in most of the characteristics evaluated.

This study examines the moisture sorption isotherms and rheological properties of indigenous Ethiopian potato (EP) starch and flour to address knowledge gaps. Moisture sorption isotherms were determined at 20°C using saturated salt solutions, with equilibrium moisture content (EMC) plotted against a _w . Five models (Guggenheim–Anderson–de Boer [GAB], Modified GAB, BET, Oswin, and Peleg) were applied, with BET and modified GAB best describing the sorption behavior. Rheological properties were analyzed using Bingham plastic, power‐law, Herschel–Bulkley, Robertson–Stiff, and Prandtl–Eyring models. The power‐law model best fit starch, while Prandtl–Eyring was optimal for flour. Both exhibited pseudoplastic behavior, with flow index ( n ) values below 1. Dynamic frequency sweep tests showed that storage modulus ( G ′) exceeded loss modulus ( G ″), indicating elasticity. The complex viscosity ( ƞ   ^∗ ) decreased with angular frequency and was lower in starch (289.92 Pa.s) than flour (346.24 Pa.s). Tan δ values (0.13 for starch, 0.18 for flour) suggested stronger elastic behavior. This study demonstrates that EP starch and flour exhibit good moisture stability and favorable rheological properties, supporting their use in food processing like thickening, gelling, and gluten‐free food products.