The Chemical Composition and Metabolic Effects of Attalea phalerata Nut Oil in Hyperlipidemic Rats Induced by a High-Fructose Diet.

The fatty acids found in nuts are important regulators of the metabolism. These acids are frequently associated with a reduction of serum cholesterol and body fat and a lower risk of developing cardiovascular disease. In this context, the aim of this study was to identify and quantify the nut oil fatty acids from Attalea phalerata and investigate their metabolic effects in rats with hyperlipidemia induced by a diet rich in fructose. Oleic and lauric acids were the major compounds found in the A. phalerata nut oil (APNO). Hyperlipidemic rats treated with APNO showed a reduction in the total serum cholesterol similar to those treated with simvastatin, an increased body temperature by 1 °C, and a reduction in the body weight gain and mesenteric depot of white adipose tissue compared to the hyperlipidemic controls rats. There was an increase in the relative liver weight of rats treated with APNO, without, however, any change in the serum markers of hepatic toxicity. In addition, there was an increase in the moisture and lipid content of the feces of the rats treated with APNO compared to the controls. Together, these results suggest that APNO has potential use in health foods and nutritional supplements to control hypercholesterolemia and obesity.

Viscoelastic Reversibility of Carrageenan Hydrogels under Large Amplitude Oscillatory Shear: Hybrid Carrageenans versus Blends.

The viscoelastic response of carrageenan hydrogels to large amplitude oscillatory shear (LAOS) has not received much attention in the literature in spite of its relevance in industrial application. A set of hybrid carrageenans with differing chemical compositions are gelled in the presence of KCl or NaCl, and their nonlinear viscoelastic responses are systematically compared with mixtures of kappa- and iota-carrageenans of equivalent kappa-carrageenan contents. Two categories of LAOS response are identified: strain softening and strain hardening gels. Strain softening gels show LAOS non-reversibility: when entering the nonlinear viscoelastic regime, the shear storage modulus G' decreases with increasing strain, and never recovers its linear value G0 after successive LAOS sweeps. In contrast to this, strain hardening carrageenan gels show a certain amount of LAOS reversibility: when entering the nonlinear regime, G' increases with strain and shows a maximum at strain γH. For strains applied below γH, G0 shows good reversibility and the strain hardening behavior is maintained. For strains larger than γH, G0 decreases significantly indicating an irreversible structural change in the elastic network. Strain hardening and elastic recovery after LAOS prevail for hybrid carrageenan and iota-carrageenan gels, but are only achieved when blends are gelled in NaCl, suggesting a phase separated structure with a certain degree of co-aggregated interface for mixed gels.

Incorporation of Locust Bean Gum and Solid Lipid Microparticles as Strategies to Improve the Properties and Stability of Calcium-Rich Soy Protein Isolate Gels.

The present study aimed to investigate the properties of calcium-rich soy protein isolate (SPI) gels (14% SPI; 100 mM CaCl2), the effects of incorporating different concentrations locust bean gum (LBG) (0.1-0.3%, w/v) to the systems and the stability of the obtained gels. Also, the incorporation of solid lipid microparticles (SLMs) was tested as an alternative strategy to improve the system's stability and, therefore, potential to be applied as a product prototype. The gels were evaluated regarding their visual aspect, rheological properties, water-holding capacities (WHCs) and microstructural organizations. The CaCl2-induced gels were self-supported but presented low WHC (40.0% ± 2.2) which was improved by LBG incorporation. The obtained mixed system, however, presented low stability, with high syneresis after 10 days of storage, due to microstructural compaction. The gels' stability was improved by SLM incorporation, which decreased the gelled matrices' compaction and syneresis for more than 20 days. Even though the rheological properties of the emulsion-filled gels (EFGs) were very altered due to the ageing process (which may affect the sensory perception of a future food originated from this EFG), the incorporation of SLMs increased the systems potential to be applied as a calcium-rich product prototype.

Dual Modification of Cassava Starch Using Physical Treatments for Production of Pickering Stabilizers.

Cassava starch nanoparticles (SNP) were produced using the nanoprecipitation method after modification of starch granules using ultrasound (US) or heat-moisture treatment (HMT). To produce SNP, cassava starches were gelatinized (95 °C/30 min) and precipitated after cooling, using absolute ethanol. SNPs were isolated using centrifugation and lyophilized. The nanoparticles produced from native starch and starches modified using US or HMT, named NSNP, USNP and HSNP, respectively, were characterized in terms of their main physical or functional properties. The SNP showed cluster plate formats, which were smooth for particles produced from native starch (NSNP) and rough for particles from starch modified with US (USNP) or HMT (HSNP), with smaller size ranges presented by HSNP (~63-674 nm) than by USNP (~123-1300 nm) or NSNP (~25-1450 nm). SNP had low surface charge values and a V-type crystalline structure. FTIR and thermal analyses confirmed the reduction of crystallinity. The SNP produced after physical pretreatments (US, HMT) showed an improvement in lipophilicity, with their oil absorption capacity in decreasing order being HSNP > USNP > NSNP, which was confirmed by the significant increase in contact angles from ~68.4° (NSNP) to ~76° (USNP; HSNP). A concentration of SNP higher than 4% may be required to produce stability with 20% oil content. The emulsions produced with HSNP showed stability during the storage (7 days at 20 °C), whereas the emulsions prepared with NSNP exhibited phase separation after preparation. The results suggested that dual physical modifications could be used for the production of starch nanoparticles as stabilizers for Pickering emulsions with stable characteristics.

Causal stability ranking.

Genotypic causes of a phenotypic trait are typically determined via randomized controlled intervention experiments. Such experiments are often prohibitive with respect to durations and costs, and informative prioritization of experiments is desirable. We therefore consider predicting stable rankings of genes (covariates), according to their total causal effects on a phenotype (response), from observational data. Since causal effects are generally non-identifiable from observational data only, we use a method that can infer lower bounds for the total causal effect under some assumptions. We validated our method, which we call Causal Stability Ranking (CStaR), in two situations. First, we performed knock-out experiments with Arabidopsis thaliana according to a predicted ranking based on observational gene expression data, using flowering time as phenotype of interest. Besides several known regulators of flowering time, we found almost half of the tested top ranking mutants to have a significantly changed flowering time. Second, we compared CStaR to established regression-based methods on a gene expression dataset of Saccharomyces cerevisiae. We found that CStaR outperforms these established methods. Our method allows for efficient design and prioritization of future intervention experiments, and due to its generality it can be used for a broad spectrum of applications.

Cassava Starch Films Containing Quinoa Starch Nanocrystals: Physical and Surface Properties.

Quinoa starch nanocrystals (QSNCs), obtained by acid hydrolysis, were used as a reinforcing filler in cassava starch films. The influence of QSNC concentrations (0, 2.5, 5.0, 7.5 and 10%, w/w) on the film's physical and surface properties was investigated. QSNCs exhibited conical and parallelepiped shapes. An increase of the QSNC concentration, from 0 to 5%, improved the film's tensile strength from 6.5 to 16.5 MPa, but at 7.5%, it decreased to 11.85 MPa. Adequate exfoliation of QSNCs in the starch matrix also decreased the water vapor permeability (~17%) up to a 5% concentration. At 5.0% and 7.5% concentrations, the films increased in roughness, water contact angle, and opacity, whereas the brightness decreased. Furthermore, at these concentrations, the film's hydrophilic nature changed (water contact angle values of >65°). The SNC addition increased the film opacity without causing major changes in color. Other film properties, such as thickness, moisture content and solubility, were not affected by the QSNC concentration. The DSC (differential scanning calorimetry) results indicated that greater QSNC concentrations increased the second glass transition temperature (related to the biopolymer-rich phase) and the melting enthalpy. However, the film's thermal stability was not altered by the QSNC addition. These findings contribute to overcoming the starch-based films' limitations through the development of nanocomposite materials for future food packaging applications.

Knockdown of CENH3 in Arabidopsis reduces mitotic divisions and causes sterility by disturbed meiotic chromosome segregation.

The histone H3 variant (CENH3) of centromeric nucleosomes is essential for kinetochore assembly and thus for chromosome segregation in eukaryotes. The mechanism(s) that determine centromere identity, assembly and maintenance of kinetochores are still poorly understood. Although the role of CENH3 during mitosis has been studied in several organisms, little is known about its meiotic function. We show that RNAi-mediated CENH3 knockdown in Arabidopsis thaliana caused dwarfism as the result of a reduced number of mitotic divisions. The remaining mitotic divisions appeared to be error-free. CENH3 RNAi transformants had reduced fertility because of frequently disturbed meiotic chromosome segregation. N-terminally truncated EYFP-CENH3(C) is deposited to and functional within Arabidopsis centromeres of mitotic chromosomes, but cannot be loaded onto centromeres of meiotic nuclei. Thus the N-terminal part is apparently required for CENH3 loading during meiosis. EYFP-CENH3(C) expression reduces the amount of endogenous CENH3, thus mimicking the effect of RNAi. The consequences of reduced endogenous CENH3 and lack of meiotic incorporation of EYFP-CENH3(C) are reduced fertility caused by insufficient CENH3 loading to the centromeres of meiotic chromosomes, subsequent lagging of chromosomes and formation of micronuclei.

Recognition of A. thaliana centromeres by heterologous CENH3 requires high similarity to the endogenous protein.

The centromere is an essential chromosomal component assembling the kinetochore for chromosome attachment to the spindle microtubules and for directing the chromosome segregation during nuclear division. Kinetochore assembly requires deposition of the centromeric histone H3 variant (CENH3) into centromeric nucleosomes. CENH3 has a variable N-terminal and a more conserved C-terminal part, including the loop1 region of the histone fold domain, which is considered to be critical for centromere targeting. To investigate the structural requirements for centromere targeting, constructs for EYFP-tagged CENH3 of A. lyrata, A. arenosa, Capsella bursa-pastoris, Zea mays and Luzula nivea (the latter with holocentric chromosomes) were transformed into A. thaliana. Except for LnCENH3, all recombinant CENH3 proteins targeted A. thaliana centromeres, but the more distantly related the heterologous protein is, the lower is the efficiency of targeting. Alignment of CENH3 sequences revealed that the tested species share only three amino acids at loop1 region: threonine2, arginine12 and alanine15. These three amino acids were substituted by asparagine, proline and valine encoding sequences within a recombinant EYFP-AtCENH3 construct via PCR mutagenesis prior to transformation of A. thaliana. After transformation, immunostaining of root tip nuclei with anti-GFP antibodies yielded only diffuse signals, indicating that the original three amino acids are necessary but not sufficient for targeting A. thaliana centromeres.

Multi-response optimization of alginate bleaching technology extracted from brown seaweeds by an eco-friendly agent.

Alginate only finds industrial applicability after undergoing a bleaching process to improve its visual appearance. Box-Behnken Design was used to optimize bleaching parameters (time, oxygen flow and temperature) for sodium alginate (SA) extracted from seaweeds using ozone as the bleaching agent. The optimal conditions (oxygen flow 2 L/min for 35 min at 25 °C) resulted in an ozone-bleached SA with a mannuronic/guluronic acids ratio of 0.70, viscosity-average molecular weight of 66.30 kDa and dynamic viscosity of 1.39 mPa.s, aligned to strong and brittle gels formation, which are potentially suitable for hydrogels and bioink application. Results indicated that ozonation caused depolymerization of the SA chain. Colorimetric parameters showed that ozone has a great bleaching efficacy. The bleached sample presented high antioxidant capacity, highlighting that discoloration by ozone might have minimal effects on the bioactive compounds which are valuable ingredients for food-based products.

Development of natural pigments microencapsulated in waste yeast Saccharomyces cerevisiae using spray drying technology and their application in yogurt.

Although Saccharomyces cerevisiae has shown potential utilization as a bio-vehicle for encapsulation, there are no reports about the functionality of natural colorants encapsulated using yeast cells. The main objectives of this study were to produce natural food coloring by encapsulating extracts from grape pomace (GP) and jabuticaba byproducts (JB) in brewery waste yeast and evaluate the functionality of the pigments by their incorporation into yogurts. Particles produced by the encapsulation of extracts from GP and JB in S. cerevisiae using 5% of yeast had the highest encapsulation efficiencies for both anthocyanins (11.1 and 47.3%) and phenolic compounds (67.5 and 63.6%), the highest concentration of both bioactives during storage and stable luminosity. Yogurts showed a pseudoplastic behavior and were considered weak gels. Colored yogurts had acceptance indexes between 73.9 and 81.4%. This work evidenced the utilization of enriched yeasts as coloring agents and interesting additives for the production of functional foods.

Production of a rich-carotenoid colorant from pumpkin peels using oil-in-water emulsion followed by spray drying.

Peels and seeds are byproducts generated during the processing of fruits and vegetables that have been cut off or rejected in the food industry. Pumpkin peels are an example of products that provide valuable nutritional aspects but that have low commercial value. This work aimed at recovering carotenoids from pumpkin peels to produce valuable powders. The pumpkin peel flour was obtained from convective drying and milling processes. Liquid-solid extraction produced the ethanol raw extract with a high carotenoid content. Carotenoid extract and Arabic gum suspensions were mixed in proportions of 1:2, 1:3, or 1:4 w/w. Emulsions produced via Ultra-Turrax (UT) and Ultra-Turrax plus high pressure (UTHP) were evaluated and spray dried. The particles carotenoid concentrations varied from 159.1 to 304.6 µg/g and from 104.3 to 346.2 µg/g for samples primarily produced via UT and UTHP, respectively. UTHP 1:3 particles showed the lowest degradation of carotenoids during 90 days of storage, with a retention index of 79%. The homogenization and spray drying techniques were proven to be suitable steps to preserve the carotenoids recovered from the byproduct studied. Microparticles can be used as a natural dye with potential use in food, pharmaceuticals, and cosmetics.

Reducing carotenoid loss during storage by co-encapsulation of pequi and buriti oils in oil-in-water emulsions followed by freeze-drying: Use of heated and unheated whey protein isolates as emulsifiers.

Buriti and pequi oils are rich in carotenoids and beneficial to human health; however, carotenoid oxidation during storage causes color loss in foods, making it difficult to use these oils in food products. This research aimed to encapsulate pequi oil and co-encapsulate pequi and buriti oils by emulsification using whey protein isolate (WPI) as an emulsifier in two forms, natural (unheated) and heated, followed by freeze-drying. The emulsions were studied by droplet size under different stress conditions, instability index, and rheology. The freeze-dried (FD) samples were studied after accelerated oxidation and the total carotenoid retention was determined; for the reconstituted FD, the zeta potential and droplet size were recorded after storage at 37 °C for 30 days. The emulsions were stable in all conditions, with average droplet sizes between 0.88 ± 0.03 and 2.33 ± 0.02 µm, and formulations with heated WPI presented the lowest instability index values. The FD's zeta potential values ranged from -50 ± 3 to -32 ± 3 mV. The co-encapsulated oils presented higher carotenoid retention (50 ± 1 and 48 ± 1%) than the free oils (31 ± 2%) after 30 days. The oxidative stability indexes were 51 ± 4 and 46 ± 3 for the co-encapsulated oils with unheated and heated WPI, respectively, and 20.5 ± 0.1 h for the free oils. FD formulations with 1:3 ratio of oil: aqueous phase and heated or unheated WPI showed the best carotenoid retention and oxidative stability, indicating that FD oil emulsions have potential as next-generation bioactive compound carriers.

Quinoa starch nanocrystals production by acid hydrolysis: Kinetics and properties.

Quinoa starch (QS) acid hydrolysis was investigated, focusing on the kinetics and physicochemical properties of nanocrystals production as a function of temperature (30, 35 and 40 °C). Waxy maize starch (WMS) was hydrolyzed at 40 °C for comparison. QS presented different hydrolysis percentages at 30 °C (63%), 35 °C (73%) and 40 °C (91%), on the fifth day. QS showed faster hydrolysis (first-order rate constant, k = 0.59 day-1) than WMS (k = 0.39 day-1) at 40 °C. Material produced at 30 °C was micrometric-sized and irregularly-shaped while that at 35 and 40 °C, was nanometric-sized and conical and parallelepiped-shaped. The hydrolysis temperature increase did not affect the crystallinity index of quinoa starch nanocrystals (QSNC), whereas zeta potential and Fourier transform infrared spectroscopy band intensities increased, and thermal transition peak temperature and thermal stability decreased when hydrolysis temperature increased. QSNC were produced at 35 and 40 °C with yields of 22.8% and 6.8%, respectively. At 40 °C, QSNC presented smaller sizes than WMS nanocrystals, but also lower yield and crystallinity index.

Sugarcane Juice with Co-encapsulated Bifidobacterium animalis subsp. lactis BLC1 and Proanthocyanidin-Rich Cinnamon Extract.

Bioactive compounds are sensitive to many factors, and they can alter the sensory characteristics of foods. Microencapsulation could be a tool to provide protection and allow the addition of bioactives in new matrices, such as sugarcane juice. This study focused on producing and evaluating the potential function of probiotics and proanthocyanidin-rich cinnamon extract (PRCE), both in free and encapsulated forms when added to sugarcane juice. The pure sugarcane juice treatment T1 was compared with other sugarcane juices to which bioactive compounds had been added; T2, a non-encapsulated Bifidobacterium animalis subsp. lactis (BLC1); T3, a non-encapsulated BLC1 and PRCE; T4, BLC1 microcapsules; and T5, with BLC1 and PRCE microcapsules. The samples were morphologically, physicochemically, rheologically, and sensorially characterized. Samples were also evaluated regarding the viability of BLC1 during the juice's storage at 4 °C. It was possible to produce probiotic sugarcane juice with non-encapsulated BLC1, but not with the addition of free PRCE, which in its free form reduced the viability of this microorganism to < 1 log CFU/mL after 7 days. The microcapsules were effective to protect BLC1 during juice storage and to maintain high contents of phenolic and proanthocyanidin compounds, although the products containing these had their viscosity altered and were less accepted than either the control or those with non-encapsulated BLC1.

Physicochemical characterization and sensory evaluation of yogurts incorporated with beta-carotene-loaded solid lipid microparticles stabilized with hydrolyzed soy protein isolate.

Beta-carotene is an extremely interesting bioactive compound in the food industry due to its antioxidant capacity and pro-vitamin A activity. However, its incorporation into food products can be challenging, as it is highly hydrophobic and chemically unstable. The aim of this study was to evaluate the feasibility of incorporating beta-carotene-loaded solid lipid microparticles (SLMs) stabilized with a hydrolyzed soy protein isolate in yogurt. The SLMs were produced using palm stearin as the lipid phase. Microparticle dispersions containing only beta-carotene and both beta-carotene and alpha-tocopherol were incorporated into yogurts, comprising 5% of its total mass. This addition itself was efficient to provide color, and the presence of the lipid microparticles did not change the physicochemical or the rheological characteristics of the product. Based on the sensory evaluation, the panelists approved the yogurt, as average grades of global acceptance were around 8.0 ("liked it very much") on the hedonic scale.

Stability of curcumin encapsulated in solid lipid microparticles incorporated in cold-set emulsion filled gels of soy protein isolate and xanthan gum.

The objective of this study was to investigate the feasibility of producing cold-set emulsion filled gels (EFG), using soy protein isolate (SPI) and xanthan gum (XG) and incorporating curcumin-loaded solid lipid microparticles (SLM). For this purpose, the formulation GXG (15%, w/v SPI, 0.1%, w/v XG and 5mM CaCl2) was selected for the production of EFG. A comparative study on the rheological and microstructural properties of non-filled gels and EFG revealed that SLM stabilized with Tween 80-Span 80 behaved as active fillers in the gel matrix, increasing the Young's modulus from 1.1 to 2.3kPa, and also increasing the values of storage and loss moduli. The incorporation of SLM also affected the microstructural organization of the systems. Whereas unfilled gels presented a microstructural organization similar to that of interpenetrated networks, EFG exhibited a microstructure with clear phase separation. The stability of encapsulated curcumin in EFG was monitored using a colorimetric test and it was confirmed that the bioactive component showed a high stability for 15days. After that period, the color started to change, indicating a decrease in curcumin concentration. The instability of curcumin was probably related to structural alterations of the EFG, which led to decreases of hardness after 7days of storage at 10°C, and to the collapse of the structures after 30days. Although formulation improvements are required, the results indicate that the encapsulation of curcumin in SLM incorporated in EFG is a potential alternative for the replacement of yellow artificial dyes in gelled food products.

Development of functional yogurt containing free and encapsulated echium oil, phytosterol and sinapic acid.

The consumption of omega-3 fatty acids and phytosterol promotes the reduction of cholesterol and triacylglycerol levels. However, such compounds are susceptible to oxidation, which hampers their application. The objective of this work was to coencapsulate echium oil, phytosterols and sinapic acid (crosslinker/antioxidant), and incorporate the obtained microcapsules into yogurt. The microcapsules were evaluated for particle size, accelerated oxidation by Rancimat, and simulation of gastric/intestinal release. The yogurts were assessed for morphology, pH, titratable acidity, color, rheology and sensory analysis. The microcapsules (13-42µm) promoted protection against oil oxidation (induction time of 54.96h). The yogurt containing microcapsules, presented a pH range from 3.89 to 4.17 and titratable acidity range from 0.798 to 0.826%, with good sensorial acceptance. It was possible to apply the microcapsules in yogurt, without compromising the rheological properties and physicochemical stability of the product.

Rheology of Emulsion-Filled Gels Applied to the Development of Food Materials.

Emulsion-filled gels are classified as soft solid materials and are complex colloids formed by matrices of polymeric gels into which emulsion droplets are incorporated. Several structural aspects of these gels have been studied in the past few years, including their applications in food, which is the focus of this review. Knowledge of the rheological behavior of emulsion-filled gels is extremely important because it can measure interferences promoted by droplets or particle inclusion on the textural properties of the gelled systems. Dynamic oscillatory tests, more specifically, small amplitude oscillatory shear, creep-recovery tests, and large deformation experiments, are discussed in this review as techniques present in the literature to characterize rheological behavior of emulsion-filled gels. Moreover, the correlation of mechanical properties with sensory aspects of emulsion-filled gels appearing in recent studies is discussed, demonstrating the applicability of these parameters in understanding mastication processes.

Effect of different polysaccharides and crosslinkers on echium oil microcapsules.

Microencapsulation by complex coacervation using gelatin and arabic gum (AG) as wall materials and transglutaminase for crosslinking is commonly used. However, AG is only produced in a few countries and transglutaminase is expensive. This work aimed to evaluate the encapsulation of echium oil by complex coacervation using gelatin and cashew gum (CG) as wall materials and sinapic acid (S) as crosslinker. Treatments were analyzed in relation to morphology, particle size, circularity, accelerated oxidation and submitted to different stress conditions. Rounded microcapsules were obtained for treatments with AG (45.45µm) and microcapsules of undefined format were obtained for treatments with CG (22.06µm). The S incorporation for 12h improved the oil stability by three fold compared to oil encapsulated without crosslinkers. Treatments with CG and S were resistant to different stress conditions similar to treatments with AG and transglutaminase, making this an alternative for delivery/application of compounds in food products.

Analysis of Histones H3 and H4 Reveals Novel and Conserved Post-Translational Modifications in Sugarcane.

Histones are the main structural components of the nucleosome, hence targets of many regulatory proteins that mediate processes involving changes in chromatin. The functional outcome of many pathways is "written" in the histones in the form of post-translational modifications that determine the final gene expression readout. As a result, modifications, alone or in combination, are important determinants of chromatin states. Histone modifications are accomplished by the addition of different chemical groups such as methyl, acetyl and phosphate. Thus, identifying and characterizing these modifications and the proteins related to them is the initial step to understanding the mechanisms of gene regulation and in the future may even provide tools for breeding programs. Several studies over the past years have contributed to increase our knowledge of epigenetic gene regulation in model organisms like Arabidopsis, yet this field remains relatively unexplored in crops. In this study we identified and initially characterized histones H3 and H4 in the monocot crop sugarcane. We discovered a number of histone genes by searching the sugarcane ESTs database. The proteins encoded correspond to canonical histones, and their variants. We also purified bulk histones and used them to map post-translational modifications in the histones H3 and H4 using mass spectrometry. Several modifications conserved in other plants, and also novel modified residues, were identified. In particular, we report O-acetylation of serine, threonine and tyrosine, a recently identified modification conserved in several eukaryotes. Additionally, the sub-nuclear localization of some well-studied modifications (i.e., H3K4me3, H3K9me2, H3K27me3, H3K9ac, H3T3ph) is described and compared to other plant species. To our knowledge, this is the first report of histones H3 and H4 as well as their post-translational modifications in sugarcane, and will provide a starting point for the study of chromatin regulation in this crop.