The effects of agitation rates from 400 to 900 rpm and aeration rates ranging from 0.18 to 0.6 vvm on biomass and citric acid production on glycerol media by acetate-negative mutants of Yarrowia lipolytica, Wratislavia 1.31 and Wratislavia AWG7, in batch culture were studied. The agitation rates of 800 and 900 rpm (at a constant aeration rate of 0.36 vvm) and aeration rates within the range of 0.24-0.48 vvm (at a constant agitation rate of 800 rpm), which generated dissolved oxygen concentration (DO) higher than 40%, were found the best for citric acid biosynthesis from glycerol. An increase in agitation rate (higher than 800 rpm) and aeration rate (higher than 0.36 vvm) had no impact on DO and citric acid production. The highest citric acid concentration (92.8 g/L) and yield (0.63 g/g) were obtained with Wratislavia 1.31 strain at 0.24 vvm. The highest volumetric citric acid production rate (1.15 g/Lh) and specific citric acid production rate (0.071 g/gh) were reached at 0.48 vvm.
Extrusion cooking technology was applied for obtaining corn extrudates fortifi ed with various level (10-20%) of rosehip pomace powder or apple pomace powder. The total polyphenols content, antioxidant activities (ABTS), organoleptic properties and colour of the extrudates were determined. Pomace addition increased the level of total polyphenols content and antioxidant activity in obtained corn -pomace extrudates, especially in samples enriched with rosehip pomace. Extrudates with 20% of rosehip pomace addition characterized the highest polyphenols content and antioxidant activity. Only the slight decrease of some quality features -shape and size, taste and fl avour, structure and colour of obtained extrudates was observed. Sample with fruit pomace addition showed increasing consistency evaluation. The extruded products by utilising fruit by-products got good evaluation of panelists and can be an excellent source of bioactive compounds in the daily human diet.
Fruit and vegetable processing by-products, undervalued until recently, are rich sources of nutrients. This study investigated properties of extruded corn puffs with addition (5–20%) of blackcurrant or chokeberry pressings. We assessed expansion rate, water absorption index (WAI) and water solubility index (WSI) of the produced extru-dates, the concentration of polyphenols, and antioxidant activity measured by FRAP method and ABTS method. The puffs with addition of chokeberry pressings had higher WSI values, higher phenolic acids, flavonols, and anthocyanins content, and higher antioxidant activity than puffcorn with addition of blackcurrant pressings. The corn puffs with addition of fruit pressings contained much higher concentrations of phenolic compounds and were characterized by much higher antioxidant activity than pure puffcorn. This confirms the usefulness of addition of such fruit processing by-products in order to manufacture functional food.
The aim of this study was to determine selected properties of extrudates produced from potato starch with the addition of ethyl alcohol. Ethyl alcohol at 5, 10, 15, and 20% concentration was added to potato starch with moisture content of 18 and 23%; the starch was then extruded in single-screw extruder. The extrusion process was carried out in three temperature variants. The resultant extrudates were determined for color, expansion ratio, and mechanical properties. Properties of the extrudates were found to depend on parameters of the extrusion process, moisture content of the extruded sample and ethanol content. Morphological characteristics of the extrudates produced were affected by temperature of the extrusion process, i.e., increasing extrusion temperature resulted in a higher expansion ratio, a lower density, and higher saturation of white color. The extrudates produced from starch with the addition of ethanol were whiter, than those prepared without ethanol. The samples produced with ethanol addition were characterized by a higher number of air spaces and thinner walls, when compared to the those prepared from starch moistened only with water. All mechanical properties were lower in the samples prepared with the addition of ethanol, as compared to the extrudates without its addition.
The aim of this study was to determine the properties of single-and double-extruded starch. Single-extruded starch was obtained using a single screw extruder at temperatures of 50-60-70°C, 90-100-120°C and 140-150-170°C, whereas double-extruded starch was obtained after grinding each of the three single-extruded starch samples and their re-extrusion at temperatures of 90-100-120°C and 140-150-170°C. The samples were determined for solubility in water and absorption capacity at a temperature of 30 and 80°C. Flow curves of the prepared pastes were plotted. Properties of double-extruded potato starch differed from those of the single-extruded starch. The study shows that the extent and direction of these changes depended on the number of the conducted extrusion processes and on their temperatures. Each successive process of extrusion and the increase in process temperatures resulted in an increased solubility of the preparations and a decrease in their water absorption capacity. Values of the rheological properties of pastes prepared from double-extruded potato starch were lower than those of the pastes produced from single-extruded potato starch.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.