Enhanced waste hot-pot oil (WHPO) anaerobic digestion for biomethane production: Mechanism and dynamics of fatty acids conversion

Application of Different Animal Fats as Solvents to Extract Carotenoids and Capsaicinoids from Sichuan Chili

Inspired by the proved dissolving power of vegetable oils for non-polar and low-polar natural compounds, animal fats with triglycerides as the major components were investigated as food-grade solvents in this study for the simultaneous extraction of carotenoids and capsaicinoids from Sichuan chili. The dissolving power of lard, beef tallow, chicken fat and basa fish oil in the extraction of er jing tiao chili was firstly compared, where animal oils with worse extraction ratios for carotenoids (0.79 mg/g in average) performed better for the extraction of capsaicinoids (0.65 mg/g in average). Furthermore, the solvent effect of animal fats on the oleo-extracts was evaluated in terms of fatty acid composition, oil quality indexes, crystal polymorphism, melting and crystallization behaviors, where no significant differences were observed between animal fats before and after extraction. The oxidative stability of animal fats could be 1.02- up to 2.73-fold enhanced after extraction and the pungency degree could reach the same spicy level as commercial hotpot oil. In addition, the Hansen solubility parameters of solvents and solutes were predicted for further theoretical miscibility study, which helps to make a better comprehension of the dissolving mechanism behind such oleo-extraction. Overall, animal fats demonstrated their considerable solvent power for extracting carotenoids and capsaicinoids simultaneously from Sichuan chili, which showed significant potential for developing a novel Sichuan spicy hotpot oil with enhanced flavor and stability.

Lipid-rich particles of processed food waste for microalgae harvest through lipid-enriched floating biomat formation

Food waste was collected from the campus canteen and lipid-rich particles (LRP) phase was evaluated to harvest Tetradesmus obliquus. Box-Behnken design showed the highest harvest efficiency (HE) of 84.69 % in run#1 (LRP = 30 %; initial OD680 = 1.75; and harvest time = 6 h). Numerical optimization ramps suggested 24.15 % (v/v) LRP ratio, initial OD680 3.00, and harvest time 3.82 h for maximum HE. Two flocs were observed, a precipitate at the bottom (B-Floc) and a floating biomat (F-Floc). Experimental results showed HE of 88.3 %, with 67 % and 33 % of the harvested biomass forming F-Floc and B-Floc, respectively. Pre-heating of LRP in a boiling water bath for 10 min (HFB-T10) promoted F-Floc proportion up to 91.6 %. In addition, HFB-T10 showed the highest FAMEs yield of 11.17 g/L of the total used volume, which was significantly higher than that of the centrifuged cells and heat-untreated biomat. Moreover, HFB-T10 showed better iodine value and cetane number of the produced biodiesel.