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Enzyme assisted aqueous extraction processing (EAEP) facilitates the production of high quality oils without the need for chemical refining. However, up to date, oil recovery remains remarkably below that found in mechanical and solvent extraction. In this study, response surface methodology (RSM) was applied, to optimize oil extraction from high oleic sunflower seeds via EAEP in a prototype automatic continuous stirred-tank extractor. Temperature, enzyme mass, water mass and proton concentration were varied for the exploration of optimum process conditions. The fit of a full second-order model was significant (p = 0.003), while the lack of fit was non-significant (p = 0.111). A local maximum was found at an extraction efficiency of 82.18%. A subsequent mass balance succeeded in reproducing the results from the RSM optimization. 93.03 ± 2.80% of the initial total mass was recovered, of which 90.90 ± 4.3% could be related to the components of the fractions. [ABSTRACT FROM AUTHOR]

Background and aims: Weed suppressive potential of annual pasture legumes has been previously described, the mechanism of interference with weeds has not been clearly elucidated. We, therefore, aimed to delineate the role of secondary metabolites synthesized and released by pasture legumes through a series of studies to: 1) characterize key metabolites present in plant tissues, residue and the rhizosphere and 2) correlate their presence with weed suppressive properties. Methods: Field and in vitro experimentations coupled with targeted and non-targeted metabolic profiling was performed to evaluate the abundance of key phytotoxic metabolites using UHPLC QTOF-MS. Further, those metabolites strongly correlated with weed suppression and phytotoxicity were predicted by chemometric analyses and their concentration evaluated in field soils collected from the same legume site. Results: Field experimentation, methanolic extracts and dried residues of Biserrula pelecinus L. and Ornithopus compressus L. exhibited marked phytotoxicity in a series of laboratory experiments. Metabolic profiling revealed that both foliar tissues and rhizosphere soils of pasture legumes possessed a high abundance of flavonoids and their precursors. Chemometric analyses suggested the strong association of quercetin, isoquercetin, kaempferol, and kaempferol-7-O-glucoside with weed suppression under field conditions. Specifically, the abundance of quercetin and kaempferol was significantly higher in soils collected from established stands of biserrula and yellow serradella in contrast to arrowleaf, gland and subterranean clover. Conclusion: Current study provided an evidence for the role of certain annual legume-produced flavonoids in weed suppression in southern Australia and further insight into their localization and release in the soil rhizosphere. [ABSTRACT FROM AUTHOR]

In recent times, the cultivation, processing and consumption of biofortified yellow-flesh cassava is of significant interest to breeders and food processors due to its relatively high pro-vitamin-A content, compared to the conventional white-flesh cassava. In light of this, osmotic dehydration (OD) kinetics of a recently released biofortified yellow-flesh cassava was compared to that of a white-flesh cassava, using salt, sugar, and salt–sugar solutions at different temperatures (30, 45, 60 °C) and fixed cube/solution-ratio. Water loss (WL) and solids gain (SG) data were fitted by non-linear regression using four models (Page, Weibull, Azuara, and Peleg). Azuara model was most appropriate in describing OD kinetics for both cultivars. Azuara estimates for equilibrium WL and equilibrium SG, respectively, ranged between 0.101–0.120 and 0.049–0.094 g/g for salt solution, 0.158–0.212 g/g and 0.107–0.268 g/g for sugar solution and 0.234–0.306 g/g and 0.189–0.276 g/g for salt–sugar solution. The best conditions for OD of both cultivars by salt solution and sugar solution was at 60 °C and 45 °C, respectively, while that for salt–sugar solution varied with cultivar. Increasing temperature increased water loss and solids gain. Salt-OD conformed to Arrhenius temperature dependence of diffusivity, but sugar-OD and salt–sugar-OD did not. Micrographs reveal biofortified yellow-flesh cassava was more susceptible to cell wall collapse than white-flesh cassava. Extent of dehydration by OD agents ranked: salt–sugar > sugar > salt. Osmotic dehydration may be useful as a means of dehydration for cassava prior to drying, and is especially relevant for the carotenoids-rich biofortified yellow cassava. [ABSTRACT FROM AUTHOR]