Green and single-step simultaneous composite starch aerogel formation-high bioavailability curcumin particle formation.

The high porosity and specific surface area of aerogels offer an ideal platform for loading bioactive molecules. In the present study, the microstructure of the bio-based starch aerogels was modulated by the incorporation of chitosan. The starch hydrogel precursors were prepared from high amylose corn starch in the presence of 0, 0.50, and 0.75 wt% chitosan. Afterward, a green single-step simultaneous aerogel formation-curcumin deposition method was applied to impregnate curcumin into the aerogels through supercritical carbon dioxide (SC-CO2) drying technology. Composite starch/chitosan aerogels showed a more open porous structure and lighter weight than the neat starch counterpart. Confocal microscopy and fluorescence spectroscopy analysis confirmed curcumin molecules' attachment to the aerogels' hydrophobic cavities. The impregnation capacity was 24-27 mg curcumin per gram of aerogel depending on the composition of the aerogels. The loading of curcumin in the aerogels significantly enhanced the bioaccessibility of curcumin in the simulated gastrointestinal fluid by almost 30-fold when compared to the unloaded curcumin. Furthermore, the bioaccessibility of the curcumin loaded in starch-chitosan composite aerogels was higher than that in neat starch aerogels. While unloaded curcumin showed an undetectable intestinal Caco-2 cell transportation, curcumin-loaded aerogels revealed a cumulative curcumin passing of 0.15-0.23 µg/mL.

Genotyping by sequencing for estimating relative abundances of diatom taxa in mock communities.

BACKGROUND: Diatoms are present in all waters and are highly sensitive to pollution gradients. Therefore, they are ideal bioindicators for water quality assessment. Current indices used in these applications are based on identifying diatom species and counting their abundances using traditional light microscopy. Several molecular techniques have been developed to help automate different steps of this process, but obtaining reliable estimates of diatom community composition and species abundance remains challenging. RESULTS: Here, we evaluated a recently developed quantification method based on Genotyping by Sequencing (GBS) for the first time in diatoms to estimate the relative abundances within a species complex. For this purpose, a reference database comprised of thousands of genomic DNA clusters was generated from cultures of Nitzschia palea. The sequencing reads from calibration and mock samples were mapped against this database for parallel quantification. We sequenced 25 mock diatom communities containing up to five taxa per sample in different abundances. Taxon abundances in these communities were also quantified by a diatom expert using manual counting of cells on light microscopic slides. The relative abundances of strains across mock samples were over- or under-estimated by the manual counting method, and a majority of mock samples had stronger correlations using GBS. Moreover, one previously recognized putative hybrid had the largest number of false positive detections demonstrating the limitation of the manual counting method when morphologically similar and/or phylogenetically close taxa are analyzed. CONCLUSIONS: Our results suggest that GBS is a reliable method to estimate the relative abundances of the N. palea taxa analyzed in this study and outperformed traditional light microscopy in terms of accuracy. GBS provides increased taxonomic resolution compared to currently available quantitative molecular approaches, and it is more scalable in the number of species that can be analyzed in a single run. Hence, this is a significant step forward in developing automated, high-throughput molecular methods specifically designed for the quantification of [diatom] communities for freshwater quality assessments.

Phylotranscriptomics reveals the reticulate evolutionary history of a widespread diatom species complex.

In contrast to surveys based on a few genes that often provide limited taxonomic resolution, transcriptomes provide a wealth of genomic loci that can resolve relationships among taxonomically challenging lineages. Diatoms are a diverse group of aquatic microalgae that includes important bioindicator species and many such lineages. One example is Nitzschia palea, a widespread species complex with several morphologically defined taxonomic varieties, some of which are critical pollution indicators. Morphological differences among the varieties are subtle and phylogenetic studies based on a few genes fail to resolve their evolutionary relationships. We conducted morphometric and transcriptome analyses of 10 Nitzschia palea strains to resolve the relationships among strains and taxonomic varieties. Nitzschia palea was resolved into three clades, one of which corresponds to a group of strains with narrow linear-lanceolate valves. The other morphological group recovered in the shape outline analysis was not monophyletic and consisted of two clades. Gene-tree concordance analyses and phylogenetic network estimations revealed patterns of incomplete lineage sorting and gene flow between intraspecific lineages. We detected reticulated evolutionary patterns among lineages with different morphologies, resulting in a putative recent hybrid. Our study shows that phylogenomic analyses of unlinked nuclear loci, complemented with morphometrics, can resolve complex evolutionary histories of recently diverged species complexes.

Developing dual nano/macroporous starch bioaerogels via emulsion templating and supercritical carbon dioxide drying.

In this study, emulsified oil droplets were employed as a temporary porogen to obtain dual nano/macroporous starch aerogels by supercritical carbon dioxide (SC-CO2) drying. This method took advantage of the solubility of the oil droplet porogens in acetone, and the insolubility of corn starch in this solvent, so this process could be integrated into the typical aerogel processing method. The effect of porogen content and starch concentration on physical and mechanical properties and the internal morphology of the obtained aerogels were studied. While the neat starch aerogel showed a compact structure in macroscale size with interconnected nanopores, the sacrificing oil droplet porogens induced macropores in the emulsion-templated aerogels. Furthermore, the nanoporous structures of starch aerogels were also well-preserved in which the macropores were surrounded by fine and interconnected nanofibrous networks. It resulted in aerogels that exhibited internal morphology in two scales (macropores and nanopores) with a high surface area (156-190 m2/g).

Enhancing the bioaccessibility of lycopene from tomato processing byproducts via supercritical carbon dioxide extraction.

Tomato peel and seed from tomato processing industry are treated as waste; however, they contain lycopene, a high-value bioactive compound. In this study, lycopene was extracted from tomato peel and seed using supercritical carbon dioxide (SC-CO2) and hexane, and the bioaccessibilities of lycopene in the SC-CO2- and hexane-extracted oleoresins were investigated for the first time. The (Z)-lycopene content of the SC-CO2-extracted oleoresin (69%) was higher than that of hexane-extracted oleoresin (45%). Separation of the insoluble fraction from the oleoresins increased the (Z)-lycopene contents of the SC-CO2- and hexane-extracted oil fractions to 80% and 49%, respectively. The bioaccessibility of total-lycopene in the oleoresins was increased by 3.3-fold via SC-CO2 extraction, which was attributed to higher (Z)-lycopene content, and small-sized uniform distribution of lycopene in the oleoresin. SC-CO2 extraction is not only a green method for extraction of bioactive compounds, but also has the potential to improve health benefits of bioactive compounds.

Evaluating the effect of cooking and gastrointestinal digestion in modulating the bio-accessibility of different bioactive compounds of eggs.

Eggs' nutritional value has been enhanced by enriching hen's diet with bioactive compounds, but factors influencing bio-accessibility are unspecified. This study investigated the effect of hen breed, diet enrichment, and cooking methods in modulating the egg compounds' bio-accessibility after gastrointestinal (GI) digestion. White Leghorn (WLH) and Rhode Island Red (RIR) hens were fed a corn-soybean-based diet enriched with flaxseed and carotenoids; eggs were collected, cooked, and subjected to simulated GI digestion. The results showed that egg proteins were equally digestible with no change in the degree of hydrolysis (DH). The linolenic fatty acid in enriched-cooked samples remained bio-accessible after GI digestion. The lutein bio-accessibility in enriched eggs decreased after GI digestion except in RIR fried sample. Eggs from WLH and RIR achieved similar peptide content after GI digestion. These results elucidate the bio-accessibility of different bioactive compounds in cooked eggs and the use of eggs as potential functional foods.

In vitro bioaccessibility of fish oil-loaded hollow solid lipid micro- and nanoparticles.

Fish oil-loaded hollow solid lipid micro- and nanoparticles were prepared by atomization of the CO2-expanded lipid mixture. The obtained particles were spherical and free-flowing with an average particle size of 6.9 µm. Fish oil loading efficiency was achieved at 92.3% (w/w). The in vitro digestive stability, lipid digestibility and EPA and DHA bioaccessibility of the fish oil-loaded particles were examined using an in vitro sequential digestion model. The mean particle diameter increased markedly after oral (15.2 µm) and gastric (32.4 µm) digestion and then decreased after the small intestinal stage (24.0 µm). Fish oil-loaded particles remained spherical and intact but mainly agglomerated on the top phase throughout the oral and gastric digestion. However, a mixed digesta was formed after the small intestinal digestion, which contained digested broken particle pieces, undigested fish oil-loaded particles, free fatty acids, monoacylglycerols and micelles. The extent of lipolysis was significantly increased for the 30% fish oil-loaded particles as compared to physical mixtures of empty hollow solid lipid particles or bulk FHSO and fish oil (p < 0.05). Moreover, EPA and DHA bioaccessibility was significantly improved from 9.7 to 18.2% with the 30% fish oil-loaded particles (p < 0.05).

Metabolic engineering of soybean seeds for enhanced vitamin E tocochromanol content and effects on oil antioxidant properties in polyunsaturated fatty acid-rich germplasm.

Soybean seeds produce oil enriched in oxidatively unstable polyunsaturated fatty acids (PUFAs) and are also a potential biotechnological platform for synthesis of oils with nutritional omega-3 PUFAs. In this study, we engineered soybeans for seed-specific expression of a barley homogentisate geranylgeranyl transferase (HGGT) transgene alone and with a soybean γ-tocopherol methyltransferase (γ-TMT) transgene. Seeds for HGGT-expressing lines had 8- to 10-fold increases in total vitamin E tocochromanols, principally as tocotrienols, with little effect on seed oil or protein concentrations. Tocochromanols were primarily in δ- and γ-forms, which were shifted largely to α- and ß-tocochromanols with γ-TMT co-expression. We tested whether oxidative stability of conventional or PUFA-enhanced soybean oil could be improved by metabolic engineering for increased vitamin E antioxidants. Selected lines were crossed with a stearidonic acid (SDA, 18:4Δ6,9,12,15)-producing line, resulting in progeny with oil enriched in SDA and α- or γ-linoleic acid (ALA, 18:3Δ9,12,15 or GLA, 18:3Δ6,9,12), from transgene segregation. Oil extracted from HGGT-expressing lines had ≥6-fold increase in free radical scavenging activity compared to controls. However, the oxidative stability index of oil from vitamin E-enhanced lines was ~15% lower than that of oil from non-engineered seeds and nearly the same or modestly increased in oil from the GLA, ALA and SDA backgrounds relative to controls. These findings show that soybean is an effective platform for producing high levels of free-radical scavenging vitamin E antioxidants, but this trait may have negative effects on oxidative stability of conventional oil or only modest improvement of the oxidative stability of PUFA-enhanced oil.

Evaluation of oil-gelling properties and crystallization behavior of sorghum wax in fish oil.

Inspired by the potential opportunities offered by sorghum as a natural wax source, the objective of this study was to investigate for the first time the potential of three types of sorghum waxes, namely, sorghum bran wax (SBW), sorghum DDGS wax (SDW), and sorghum kernel wax (SKW), as an oleogelator. All the three sorghum waxes showed good gelation properties with minor differences. Fast cooling rate and ultrasonic treatment favored the oil-gelling capacity and reduced oil loss by reducing the crystal size. All sorghum wax oleogels exhibited two common x-ray diffraction peaks around d-value of 0.415 nm and 0.374 nm, suggesting the evidence of a hexagonal symmetry and ß' crystals. Faster cooling rate resulted in an earlier onset of crystallization and ultrasonic treatment narrowed the melting range. Oxidation of fish oil in the sorghum wax oleogels were delayed considerably compared to free fish oil, while SDW generated the most stable oleogels.

A novel and green nanoparticle formation approach to forming low-crystallinity curcumin nanoparticles to improve curcumin's bioaccessibility.

Health-promoting effects of curcumin are well-known; however, curcumin has a very low bioavailability due to its crystalline structure. The main objective of this study was to develop a novel green nanoparticle formation method to generate low-crystallinity curcumin nanoparticles to enhance the bioavailability of curcumin. Nanoporous starch aerogels (NSAs) (surface area of 60 m2/g, pore size of 20 nm, density of 0.11 g/cm3, and porosity of 93%) were employed as a mold to produce curcumin nanoparticles with the help of supercritical carbon dioxide (SC-CO2). The average particle size of the curcumin nanoparticles was 66 nm. Impregnation into NSAs decreased the crystallinity of curcumin and did not create any chemical bonding between curcumin nanoparticles and the NSA matrix. The highest impregnation capacity was 224.2 mg curcumin/g NSA. Curcumin nanoparticles significantly enhanced the bioaccessibility of curcumin by 173-fold when compared to the original curcumin. The concentration of curcumin in the bioaccessible fraction was improved from 0.003 to 0.125 mg/mL by impregnation of curcumin into NSAs (42-fold). This is a novel approach to produce food grade curcumin nanoparticles with reduced crystallinity and maximize the utilization of curcumin due to increased bioaccessibility.

In vitro bioaccessibility of novel low-crystallinity phytosterol nanoparticles in non-fat and regular-fat foods.

Crystalline structure of phytosterols leads to poor bioavailability and makes their incorporation into foods challenging. Bioaccessibility of first-of-their-kind low-crystallinity phytosterol nanoparticles impregnated in nanoporous starch aerogels (PS-NSA) was evaluated in non-, low-, and regular-fat solid and aqueous food formulations, namely, granola bars and puddings for the first time. Bioaccessibility of the phytosterol nanoparticles was significantly higher than that of crude phytosterols in all food formulations (p < .05); it was 88.2 and 91.8% for low- or regular-fat granola bars, respectively, whereas bioaccessibility of crude phytosterols was ca. 30% in those formulations. However, decreasing the lipid content to zero resulted in lower phytosterols' bioaccessibilities from both PS-NSA (53%) and crude phytosterols (ca. 16%) in non-fat granola bars. Bioaccessibility of crude phytosterols (2%) was significantly enhanced with PS-NSA (19%) in the pudding formulation. PS-NSA allows preparation of low- and non-fat foods enriched with phytosterols while enhancing the health benefits of phytosterols with smaller doses.

In Vitro Bioaccessibility of Low-Crystallinity Phytosterol Nanoparticles Generated Using Nanoporous Starch Bioaerogels.

Phytosterols are natural health-promoting bioactive compounds; however, phytosterols have very limited bioavailability due to their crystalline lipophilic structure. With the aim of improving bioaccessibility, low-crystallinity phytosterol nanoparticles were generated by supercritical carbon dioxide (SC-CO2 ) impregnation of phytosterols into nanoporous starch aerogels (NSAs). The in vitro bioaccessibility of the phytosterol nanoparticles (35%) was significantly higher than that of the crude phytosterols (3%) after sequential oral, gastric, and intestinal digestion. The percentages of starch hydrolysis were not different among the various NSA preparations and reached to 64% after sequential digestion. The zeta potential of the phytosterol nanoparticles was higher compared to that of crude phytosterols in the micellar phase; indicating higher stability. The findings of this study support the use of NSA to produce nanoparticles of reduced crystallinity to improve the bioaccessibility of the lipophilic bioactive compounds. PRACTICAL APPLICATIONS: This novel process can decrease the size and crystallinity of phytosterols and thus improve phytosterols' bioavailability. It is a blueprint to apply to other water insoluble food bioactives. This novel approach may (i) improve the health benefits of water-insoluble bioactives; (ii) enable food manufacturers to add water-insoluble bioactives into low- and high-fat foods to produce health-promoting foods; and (iii) enhance the cost-benefit ratio of water insoluble bioactives.

Expression of the Arabidopsis WRINKLED 1 transcription factor leads to higher accumulation of palmitate in soybean seed.

Soybean (Glycine max [L.] Merr.) is a commodity crop highly valued for its protein and oil content. The high percentage of polyunsaturated fatty acids in soybean oil results in low oxidative stability, which is a key parameter for usage in baking, high temperature frying applications, and affects shelf life of packaged products containing soybean oil. Introduction of a seed-specific expression cassette carrying the Arabidopsis transcription factor WRINKLED1 (AtWRI1) into soybean, led to seed oil with levels of palmitate up to approximately 20%. Stacking of the AtWRI1 transgenic allele with a transgenic locus harbouring the mangosteen steroyl-ACP thioesterase (GmFatA) resulted in oil with total saturates up to 30%. The creation of a triple stack in soybean, wherein the AtWRI1 and GmFatA alleles were combined with a FAD2-1 silencing allele led to the synthesis of an oil with 28% saturates and approximately 60% oleate. Constructs were then assembled that carry a dual FAD2-1 silencing element/GmFatA expression cassette, alone or combined with an AtWRI1 cassette. These plasmids are designated pPTN1289 and pPTN1301, respectively. Transgenic events carrying the T-DNA of pPTN1289 displayed an oil with stearate levels between 18% and 25%, and oleate in the upper 60%, with reduced palmitate (<5%). While soybean events harboring transgenic alleles of pPTN1301 had similar levels of stearic and oleate levels as that of the pPTRN1289 events, but with levels of palmitate closer to wild type. The modified fatty acid composition results in an oil with higher oxidative stability, and functionality attributes for end use in baking applications.

In Vitro Digestibility of Nanoporous Wheat Starch Aerogels.

This study reports the in vitro digestibility of starch aerogels for the first time. The relative crystallinities of the wheat starch aerogels (WSAs) produced at gelatinization temperatures of 120 °C (WSA-120C), 130 °C (WSA-130C), and 120 °C with the addition of sodium metaphosphate (STMP) (WSA-STMP) and xerogel were similar. However, WSA-120C showed the highest amylose-lipid complex content. The addition of STMP created some cross-linked starch with a phosphorus content of 0.023%. Resistant starch (RS) contents of WSA-STMP (33.5%) and xerogel (26.9%) were higher than the other samples when they were uncooked prior to digestion. Nevertheless, the RS contents of WSA-STMP and xerogel decreased drastically with cooking. RS contents of WSA-120C and WSA-130C were stable with cooking and provided 4.5- and 3.0-fold increases in the RS content, respectively. WSA is a promising functional food ingredient with a high RS content, even after cooking.

Optimization of artemisinin extraction from Artemisia annua L. with supercritical carbon dioxide + ethanol using response surface methodology.

Malaria is a high priority life-threatening public health concern in developing countries, and therefore there is a growing interest to obtain artemisinin for the production of artemisinin-based combination therapy products. In this study, artemisinin was extracted from the Artemisia annua L. plant using supercritical carbon dioxide (SC-CO2 ) modified with ethanol. Response surface methodology based on central composite rotatable design was employed to investigate and optimize the extraction conditions of pressure (9.9-30 MPa), temperature (33-67°C), and co-solvent (ethanol, 0-12.6 wt.%). Optimum SC-CO2 extraction conditions were found to be 30 MPa and 33°C without ethanol. Under optimized conditions, the predicted artemisinin yield was 1.09% whereas the experimental value was 0.71 ± 0.07%. Soxhlet extraction with hexane resulted in higher artemisinin yields and there was no significant difference in the purity of the extracts obtained with SC-CO2 and Soxhlet extractions. Results indicated that SC-CO2 and SC-CO2 +ethanol extraction is a promising alternative for the extraction of artemisinin to eliminate the use of organic solvents, such as hexane, and produce extracts that can be used for the production of antimalarial products.

Development of omega-3-rich Camelina sativa seed oil emulsions.

Camelina sativa seed is an underutilized oil source rich in omega-3 fatty acids; however, camelina oil is not fully explored for food applications. Its high omega-3 content makes it susceptible to oxidation, which may limit food applications. Therefore, the main objective of this study was to investigate the potential of camelina seed oil to form physically and oxidatively stable emulsions as a potential delivery system for omega-3 fatty acids. Effects of homogenization conditions, namely, pressure (15 MPa-30 MPa), number of passes (1,3,5, and 7), and type of homogenizers (high pressure and high shear) on the structural properties and stability of camelina seed oil emulsions stabilized with whey protein isolate were studied. High homogenization pressure (30 MPa) and number of passes (>3) reduced the particle size (278 nm) and formed more physically and oxidatively stable emulsions compared to high shear homogenization; high shear homogenization generated bigger oil particles (~2,517 nm). Apparent viscosity and consistency index (k) decreased with increasing pressure, number of passes, and shear rate. Emulsions prepared with high pressure homogenization at both 15 and 30 MPa with 3 and more passes did not exhibit any peroxide formation over 28 days. Results indicated that camelina seed oil is a promising alternative oil source to form stable omega-3-rich emulsions for food applications.

Lipid composition and emulsifying properties of Camelina sativa seed lecithin.

There is no information on the chemical composition of camelina seed lecithin; therefore, the objective of this study was to investigate the chemical composition and emulsifying properties of lecithin recovered from camelina seed oil by water (WDCL) and enzymatic degumming (EDCL) using phospholipase A1 (PLA1). The lecithin obtained by both WDLC and EDLC was rich in phosphatidylinositol (PI), and contents were 37.8 and 25.2wt%, respectively. Lecithin recovered by enzymatic degumming contained more lysophospholipids compared to water degumming. The saturated fatty acid content of the EDCL was significantly higher than that of the WDCL. Emulsions stabilized using EDCL resulted in the highest stability when deionized water was used as the aqueous phase (original pH); however, at pH=7.5, emulsions stabilized using EDCL and WDCL were less stable compared to the emulsion stabilized with soy lecithin. Results showed that camelina seed lecithin is a promising alternative PI-rich emulsifier for various food applications.

Formation of complexes between tannic acid with bovine serum albumin, egg ovalbumin and bovine beta-lactoglobulin.

Tannic acid (TA) shows strong interactions with proteins and the resulting complexes can be utilized as delivery systems for oral drugs. The complexation of TA with three proteins including bovine serum albumin (BSA), egg ovalbumin (EA) and bovine beta-lactoglobulin (BLG) at pH 7.4 was studied. The tryptophan (Trp) fluorescence of all three proteins was quenched by TA in a static quenching mechanism. BLG showed the highest binding affinity and a smallest binding distance with TA which may suggest that BLG-TA is the most stable complex. The results of circular dichroism, synchronous and three-dimensional fluorescence spectra suggested that the protein structures have been changed at different levels and helix structure was affected more significant than ß-strand. Zeta-potential of all three proteins was more negative after binding with TA, which is favorable for the stabilization of protein based nanoparticles. Information derived from this work could be important to potentially use TA-protein complexes as nanoencapsulation systems for oral drug delivery.

Encapsulation of fish oil into hollow solid lipid micro- and nanoparticles using carbon dioxide.

Fish oil was encapsulated in hollow solid lipid micro- and nanoparticles formed from fully hydrogenated soybean oil (FHSO) using a novel green method based on atomization of supercritical carbon dioxide (SC-CO2)-expanded lipid. The highest fish oil loading efficiency (97.5%, w/w) was achieved at 50%, w/w, initial fish oil concentration. All particles were spherical and in the dry free-flowing form; however, less smooth surface with wrinkles was observed when the initial fish oil concentration was increased up to 50%. With increasing initial fish oil concentration, melting point of the fish oil-loaded particles shifted to lower onset melting temperatures, and major polymorphic form transformed from α to ß and/or ß'. Oxidative stability of the loaded fish oil was significantly increased compared to the free fish oil (p<0.05). This innovative method forms free-flowing powder products that are easy-to-use solid fish oil formulation, which makes the handling and storage feasible and convenient.

Effect of Extraction Method on the Oxidative Stability of Camelina Seed Oil Studied by Differential Scanning Calorimetry.

Camelina seed is a new alternative omega-3 source attracting growing interest. However, it is susceptible to oxidation due to its high omega-3 content. The objective of this study was to improve the oxidative stability of the camelina seed oil at the extraction stage in order to eliminate or minimize the use of additive antioxidants. Camelina seed oil extracts were enriched in terms of natural antioxidants using ethanol-modified supercritical carbon dioxide (SC-CO2 ) extraction. Oxidative stability of the camelina seed oils extracted by ethanol modified SC-CO2 was studied by differential scanning calorimeter (DSC), and compared with cold press, hexane, and SC-CO2 methods. Nonisothermal oxidation kinetics of the oils obtained by different extraction methods were studied by DSC at varying heating rates (2.5, 5, 10, and 15 °C/min). Increasing ethanol level in the ethanol-modified SC-CO2 increased the oxidative stability. Based on oxidation onset temperatures (Ton ), SC-CO2 containing 10% ethanol yielded the most stable oil. Oxidative stability depended on the type and content of the polar fractions, namely, phenolic compounds and phospholipids. Phenolic compounds acted as natural antioxidants, whereas increased phospholipid contents decreased the stability. Study has shown that the oxidative stability of the oils can be improved at the extraction stage and this may eliminate the need for additive antioxidants.