Subcritical water (SCW) hydrolysis was applied to valorize the low-valued ray-finned fish () into valuable protein hydrolysates, employing N and CO as pressurization agents at varying temperatures (140, 160, 180, and 200 °C). The degree of hydrolysis (DH) and total free amino acid content increased with temperature for both pressurizing agents. The highest DH (54.
View Article and Find Full Text PDFA green strategy employing water as solvent has been adopted to obtain protein hydrolysates from fish meal (FM), its water-soluble fraction (WSP), and its non-water-soluble fraction (NSP). The techno-functional properties of the hydrolysates have been investigated and compared to hydrolysates obtained with Alcalase®. In general, SWH hydrolysates presented higher content of free amino acids and higher degree of hydrolysis, which reflected on the molecular size distribution.
View Article and Find Full Text PDFA systematic kinetic study was conducted in subcritical water medium in the temperature range from 150 to 200 °C for pure glucose, xylose, proline and aspartic acid as well as binary mixtures of sugars + amino acids to understand the reaction kinetics and interactions among biomass components and to discern the influence of Maillard reaction (MR) on the overall reaction kinetics. The main degradation products identified for glucose and xylose were the respective dehydration products, hydroxymethyl furfural and furfural, yielding an increasing solid residue with temperature (15.9 wt% at 200 °C) with an augmented heating value.
View Article and Find Full Text PDFThe hydrolysis of the water-soluble protein (WSP) fraction from tuna fish meal was evaluated by subcritical water (subW) by using N and CO as different pressurization agents in the temperature range from 140 to 180 °C. For both gases, the amino group release increased by increasing working temperature while the Lowry response decreased due to production of smaller-size peptides and free amino acids. The free amino acid content was higher with CO than with N.
View Article and Find Full Text PDFThe fishery industry generates large amounts of waste (20-75% (/) of the total caught fish weight). The recovery of bioactive compounds from residues and their incorporation in cosmetics represents a promising market opportunity and may contribute to a sustainable valorisation of the sector. In this work, protein-rich extracts obtained by high-pressure technologies (supercritical CO and subcritical water) from sardine () waste and codfish () frames were characterized regarding their cosmeceutical potential.
View Article and Find Full Text PDFThe double effect of supercritical carbon dioxide, sc-CO, in a biorefinery concept applied to brewer's spent grain (BSG) was assessed in this work. Extraction conditions to remove and valorize the lipophilic fraction were studied (20-40 MPa and 40-80 °C) obtaining a maximum yield of 5.70 ± 0.
View Article and Find Full Text PDFThe valorization of Atlantic cod () frames from a filleting industry was investigated using subcritical water extraction and hydrolysis (SBW) at different temperatures (90, 140, 190 and 250 °C) and 100 bar to obtain extracts rich in proteins, peptides and amino acids. Up to 57.7 g of extract per 100 g of codfish frames were obtained, with nearly total recovery of the protein fraction.
View Article and Find Full Text PDFParticles from Gas-Saturated Solutions (PGSS)-drying has been used as a green alternative to encapsulate omega-3 polyunsaturated fatty acids (n-3 PUFAs) at mild, non-oxidative conditions. PGSS-dried particles have been compared to those obtained by conventional drying methods such as spray-drying and freeze-drying, finding encapsulation efficiencies (EE) up to 98% and spherical morphology for PGSS- and spray-dried particles. Freeze-dried powders showed irregular morphology and EE from 95.
View Article and Find Full Text PDFMono- and diacylglycerols rich in omega-3 have a great interest due to their good bioavailability and oxidation stability compared with other kind of omega-3 concentrates. The main drawback in mono- and diacylglycerols production by glycerolysis is the immiscibility of the substrates, oil and glycerol. To improve mass transfer rates, avoiding the use of organic solvents, emulsification of both reactants as reverse micelles (glycerol-in-oil) was carried out previous to lipase-catalyzed sardine oil glycerolysis.
View Article and Find Full Text PDFThe ethanolysis of fish oil in various reaction medium (tert-pentanol, n-hexane and solvent free system) catalyzed by the immobilized commercial lipase Lipozyme(®) 435 (Candida Antarctica) at atmospheric pressure has been studied in this work. The effect of some kinetic parameters, such as the amount of lipase, temperature and the initial reactant molar ratio ethanol:oil on monoacyglyceride and ethyl ester yield has been analyzed. Experimental data were successfully correlated by a simple kinetic model based on the elementary reactions proposed in this work.
View Article and Find Full Text PDFThe nuclear uptake and retention of [3H]testosterone or one of its metabolites and the aromatization of testosterone to estrogen were examined in the Swiss--Webster mouse. Castrated male mice were injected with 0.2 micrograms of either [1 alpha, 2 alpha-3H(N)]testosterone or [1 beta, 2 beta-3H(N)]testosterone per 100 g of body weight and killed one and one-half hours later.
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