•MAGs rich in ω-PUFAs is produced by combining enzymatic glycerolysis with SPD process.•SPD enables a distillate stream of MAGs with 91% purity and 94% overall recovery.•The capability of SPD to ...directly concentrate n-3 PUFAs in MAG form is demonstrated.•A processing diagram for scalable production of n-3 PUFAs enriched MAG is mapped out.
Production of monoacylglycerols (MAGs) rich in ω-3 polyunsaturated fatty acids (n-3 PUFAs) was conducted through short path distillation (SPD) of an acylglycerol mixture (containing 67% MAGs) produced by enzymatic glycerolysis of sardine oil with glycerol. A stepwise SPD process in a UIC KDL 5 system (vacuum 10−3mbar, feeding flow 1.0mL/min) was proceeded: the first distillation performed at evaporator temperature (TE) of 110°C to remove glycerol completely and most of FFAs; and the second distillation at optimized TE 155°C; resulting in a stream distillate with 91% purity and 94% overall recovery of MAGs. This work also demonstrated that SPD is able to concentrate n-3 PUFAs in MAG form by distilling at proper TE e.g. 125°C, where n-3 PUFAs are concentrated in the residues. Moreover, this work mapped out a complete processing diagram for scalable production of n-3 PUFAs enriched MAGs as potential food emulsifier and ingredient.
Physical modifications of flours are an environment-friendly technology receiving increasing attention for widening the range of utilization of these raw materials. Rice flour was modified with ...ultrasound treatments at a frequency of 24 kHz and varying treatment time (2–60 min) and flour concentration (5–30%) in the dispersion. The effect of the modification was measured in the flours' physical, functional, pasting and rheological properties. Particle size of treated samples was reduced, and particle's disruption was observed by SEM; this had an impact on the water absorption ability, as shown by a sharp increase of swelling power. The thermal properties showed a significant reduction of gelatinization enthalpy, as well as narrowing of the gelatinization temperature range, characteristic of better packed starch crystalline structures after sonication. Modified patterns in starch and proteins were obtained with XRD and FTIR, which indicated impact to their crystalline and amide I secondary structures as a consequence of ultrasonication. Pasting profiles were found to be reduced with increasing treatment time, while higher concentrations did not significantly change the modification achieved. The pasting temperature was found to be significantly increased in all treated samples. Ultrasound treatment led to gels with higher strength, obtaining lower values of tan δ with increasing sonication time and flour concentration. Ultrasound allowed the modulation of rice flour functionality, being the effect independent on the concentration of the treated flour dispersion, up to 30%, and increased by treatment time up to 10 min; for longer treatments not many differences were found.
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•Pasting curves of rice flour decreased significantly with the ultrasound treatment.•Pasting and gelatinization temperatures increased in sonicated flours.•Ultrasound treatment changed particle size and surface area of rice granules.•Sonicated rice flour led to stronger and more elastic gels than native one.•Ultrasounds modified XRD and FTIR patterns of starch and proteins in rice flour.
Microwave radiation (MW) is an environment-friendly technology used to physically modify flours. Rice flour was MW-treated at different moisture content (MC) (3 %, 8 %, 13 %, 15 %, 20 % and 30 %). In ...vitro starch digestibility was determined and related to the changes caused by MW treatment to flours' structure and thermal properties, which were influenced by MC. A reduction of 49 % and 65 % in the gelatinization enthalpy of samples treated at 20 % and 30 % MC denoted a partial gelatinization. A loss of granular crystallinity in treated samples was confirmed by XR-diffraction and FTIR, particularly at 15 %, 20 % and 30 % MC. MW promoted the formation of random-coil, α-helix and β-turn protein structure, and the disappearance of LF-β-sheet. Morphological differences were found between samples treated at 8 % MC (loss of polygonal structure, protein layer covering granules' surface and small holes) and 30 % MC (rounded and aggregated granules, covered with exudate amylose). In vitro starch digestibility revealed that samples treated at 20 % and 30 % MC showed 40 % and 47 % higher rapidly digestible starch, 48 % and 70 % lower slowly digestible starch and 90 % lower resistant starch than the untreated flour. Flour MC in MW-treatment allowed the modulation of structural and thermal characteristics of rice flour and consequently its starch hydrolysis rate.
•Microwave treatment (MWT) modified the intensity of rice flour X-ray diffractograms.•Signs of partial gelatinization were found in samples treated at 20 and 30 % humidity.•The MWT decreased the 1047:1022 ratio in FTIR spectra regardless the flour humidity.•The MWT promoted the formation of random coil, α-helix and β-turn protein structure.•The flour humidity during the MWT determined the rate of starch hydrolysis.
The capacity of microwave (MW)-assisted dry-heat and heat-moisture treatments to modify techno-functional properties and gel viscoelasticity of rice flour was studied. Flour samples at 30%, 20%, 15%, ...13%, 8%, and 3% of moisture content (MC) were microwaved for 480 s at 18W/g. The 3% MC sample was unmodified by treatment. However, the 8% MC sample was one of the most affected, along with the 20% and 30% samples, indicating that a small amount of water can plasticize rice flour enough to rearrange its biopolymers molecules (mainly starch) responsible for the modifications. The lowest peak and breakdown viscosities and the highest pasting temperature were found in the 30% MC sample, which varied −58%, −89%, and +8 °C respectively, from native flour. DSC revealed partial pre-gelatinization in the 20% and 30% MC samples. Swelling power increased in all samples after treatment, while water solubility only increased in the 8% and 30% MC samples. Treatments promoted gel stability and enhanced viscoelastic moduli, particularly in the 8% and 20% MC samples. Flour MC in MW-assisted treatment allowed the modulation of techno-functional properties of rice flour and rheological and thermal characteristics of their gels.
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•The flour water content determined the temperature reached during the MW treatment.•The swelling power increased in all the MW treated-samples.•Treatments at 8% and 30% humidity increased the apparent amylose content of flour.•The treatments promoted gels stability and resulted in enhanced viscoelastic moduli.•Treatments at 20% and 30% humidity led to a partial gelatinization of rice flour.
Quinoa has recently been considered as an alternative oilseed crop due to the quality and quantity of its lipid fraction. Supercritical fluid extraction (SFE) was used as a green process to extract ...quinoa oil without solvent residues. Defatted quinoa flour is a potentially valuable raw material whose performance as food ingredient needs to be established. Structural, physicochemical, pasting, and thermal properties of quinoa (cv. Titicaca) defatted by supercritical CO
2
extraction (DQ-SCCO
2
) were characterized. In vitro starch enzymatic susceptibility was also evaluated. Full fatted quinoa (NDQ) and quinoa defatted by hexane extraction (DQ-HX) were also evaluated in parallel. DQ-SCCO
2
showed a disrupted and microporous structure due to the pressurization/depressurization of CO
2
in SFE. However, its viscometric profile was very similar to that of NDQ, while that of DQ-HX was significantly lower. This denotes a physical/thermal modification of the flour as a result of the higher temperature applied during hexane extraction, 68 °C, versus 40 °C in SFE. Defatted samples showed lower pasting temperatures (4–5 °C) and higher amylopectin retrogradation extent than NDQ. Quinoa showed a very high enzymatic susceptibility regardless its lipid content; 90% of the starch was hydrolyzed by digestive enzymes in 20 min in the three samples. However, defatted quinoa had lower slowly digestible starch content than NDQ, being the lowest value for DQ-SCCO
2
sample. The work confirms the feasibility of using DQ-SCCO
2
as a raw material in food applications, free of solvent residues, and with a technological quality superior to that obtained by extraction with organic solvents.
The quality of quinoa flour is greatly determined by its non-starch components, mainly protein and lipids. Dry fractionation has an important impact on the composition and physicochemical properties ...of quinoa flour and grits. Quinoa cv. Titicaca, the most extensively grown in Europe and little studied so far, was used in this work. Hydration, techno-functional, rheological and thermal properties of three quinoa fractions obtained by dry fractionation (fine, medium and coarse) were evaluated and related to their particle size and composition. The medium fraction (~500 μm) was enriched in protein (50%) and lipids (80%) and depleted in starch (30%) with respect to the original grain; while the coarse fraction (~1000 μm) was enriched in starch (7%) and reduced in protein (15%). The fine fraction showed the most similar functional, pasting and rheological properties to the whole grain quinoa flour. The coarse fraction led to the most consistent gels, with the elastic (G′) and viscous (G'') moduli being ten and twenty times higher than those found in the other quinoa fractions and the whole grain flour. The degree of retrogradation as well as the formation of the amylose-lipid complex were markedly affected by the particle size and not so by the composition of each fraction. This work allows to conclude that dry fractionation of quinoa grains is a feasible procedure to tailoring the nutritional profile of the flour and its techno-functional and rheological properties.
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•An efficient dry milling process of quinoa produces nutritional enriched fractions.•Fraction with medium particle size (~500 μm) was enriched in protein and lipids.•The coarse fraction (~1000 μm) led to gels much more consistent.•Amylose-lipid complex formation decreased in the larger particle size fractions.•Amylopectin retrogradation extent increased in the larger particle size fractions.
The production of polyunsaturated fatty acids (PUFAs) concentrates by enzymatic catalysis has gained interest due to their stereospecificity and the milder conditions employed compared to the use of ...inorganic catalysts. The enzymatic glycerolysis of sardine oil by Lipozyme® 435 to get PUFA concentrates in the forms of di- and monoacylglycerols (DAGs, MAGs) in an optimized amount of tert-butanol as the organic solvent was studied. First, mass transfer limitation of the reaction system was analyzed. The effects of different operating variables such as lipase loading, temperature and feed composition were investigated. A semi-empirical kinetic model based on the reversible elementary reactions of glycerolysis and hydrolysis of the glycerides was employed to correlate the experimental kinetic data. A molar ratio glycerol:oil of 3:1 was the optimum, which produced more than 84 wt% of MAG at 323 K. A comparison with other glycerolysis systems was performed using MAG yield, reaction rate and significance of kinetic parameters.
This work presents a detailed kinetic study of enzymatic glycerolysis of sardine oil catalyzed by the commercial lipase Lipozyme® 435. Glycerolysis is carried out in tert-butanol to create a homogeneous system avoiding mass transfer limitations.
Mono- 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. Substrate emulsification yielded higher reaction rates compared to kinetics with no previous emulsification, but still lower than in organic solvents. To avoid the use of organic solvent, SC-CO2 was used as reaction medium but no kinetic advantages were demonstrated in the pressure range from 15 to 25 MPa. By increasing temperature, from 40 to 90°C, reaction rates increased both in a solvent-free system and in SC-CO2 medium. It was also found that an increase in temperature does not lead to an increase in the final oxidation status of the reaction products. This behavior was due to the adsorption capacity of the Lipozyme 435 support, giving lower oxidation status at the highest temperature, 80–90°C.
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•Emulsified substrates improve the initial rate in solvent-free glycerolysis.•The use of SC-CO2 presents no kinetic advantages in glycerolysis reaction.•Hydroperoxides are adsorbed on the lipase support.•Sorption of hydroperoxide is favored at high reaction temperatures.
The 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. At high initial reactant molar ratio the three elementary steps can be considered as irreversible. However the reaction rate constants ratio for the deacylation of monoglyceride to glycerol decreased by decreasing the molar ratio ethanol:oil. The reaction rates are slower in n-hexane as reaction medium compared to tert-pentanol and a solvent-free system, at the experimental conditions essayed in this work. In this last case, ethanol acts as solvent for reaction and as reactant.
Oxidation kinetics of sardine oil have been determined at 40, 65 and 90 °C by measuring concentration of primary and secondary oxidation products in the presence of commercial immobilized lipases ...(Lipozyme 435, Lipozyme RM and Lipozyme TL) commonly used as biocatalyst in lipid modification reactions. Oxidation products concentration was found to be lower when the immobilized lipases were added at the highest temperatures studied. The lowest oxidation indices were observed in the presence of Lipozyme RM.
Although the mechanism to explain this decrease in the oxidation products is not still clear, these results might indicate that the use of these immobilized lipases in lipase-catalyzed reactions of fish oils at high temperature (90 °C) will yield higher reaction rates and also a reduction of the oxidation products formed due to oxidation of polyunsatured fatty acids.
•PV and TBARS increase faster than AV in the autoxidation of sardine oil.•Oxidation products concentration decreased in the presence of immobilized lipases.•The decrease was higher for PV and TBARS than anisidine reacted compounds.•Lipozyme RM presented the best results to obtain lower oxidation indices.
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