Influence of temperature and heating duration on the thermal stability and flow characteristics of oil extracted from undersized crawfish (Procambarus clarkii) using non-solvent method

Undersized crawfish (UC) have less economic value for sale in live or processed tail meat markets. Therefore, this study's objectives were to extract crawfish oil (CO) from UC and determine the impact of temperature and heating duration on CO's thermal stability and flow properties. However, extracting oil from these undersized specimens could potentially add value to the crawfish industry. Crawfish minced meat (CMM) was obtained by passing cooked and chilled UC through a pilot scale deboning machine. CO was extracted by agitating CMM at 70°C for 30 min, followed by centrifugation at 10,000×g. CO was analyzed for inherent physicochemical characteristics, heating time (0–8 h), temperature (45–85°C) effects on peroxide value (PV) and astaxanthin (ASX) content, and flow properties at 5–35°C. ASX content, PV, water activity, bulk density, specific gravity, and free fatty acid values in CO were found to be 1.52 ± 0.06 mg/g oil, 0.22 ± 0.07 meq/kg, 0.56 ± 0.02, 0.88 ± 0.00, 0.90 ± 0.00 g/mL, and 0.11 ± 0.04%, respectively. ASX content in CO showed no significant change within or between same-temperature and different-temperature heated samples after 8 h. PV increased significantly from 0 to 8 h of heating at all tested temperatures (45, 65, and 85°C; Δ = 0.31, 0.51, and 10.76 meq/kg, respectively). CO had pseudoplastic characteristics below 30°C and Newtonian flow from 30 to 35°C. The Arrhenius equation suitably described the relationship between temperature and apparent viscosity of CO. This study characterized a seldom-researched oil (CO containing ASX) and provided insight into its ability to resist thermal degradation.