Síntese e caracterização do poliestireno expansível: emprego de água como agente de expansão

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência e Engenharia de MateriaisO poliestireno expansível, EPS, pode ser definido como uma matriz do polímero onde se encontra impregnado um agente de expansão. Esse agente de expansão é um fluido que, pelo aumento da temperatura, aumenta seu volume e força a partícula a se expandir. O EPS convencional, aquele disponível comercialmente, utiliza hidrocarbonetos voláteis como agente de expansão. O emprego de novas substâncias que poderiam atuar como promotores de expansão é uma alternativa para a redução de custo do produto final e tem sido reportado nos últimos anos. Particularmente, a substituição por água aparece como uma possibilidade de interesse. Este trabalho apresenta uma metodologia para a obtenção de EPS com água como agente de expansão. Ainda, técnicas de caracterização foram aplicadas a fim de elucidar as relações entre as propriedades deste material e seu comportamento frente ao processo de expansão. Sucintamente, promoveu-se a incorporação da água nas pérolas de poliestireno para, assim, dotá-lo da capacidade de expandir. A água foi pulverizada, ou aspergida, sobre o monômero e, pela ação do surfactante, um sistema em emulsão foi formado. O produto final foi produzido em suspensão e a reação seguiu até que as gotas do monômero fossem convertidas em pérolas sólidas contendo o agente de expansão espalhadas no seu interior. Foram determinados peso molecular médio ponderal, teor de monômero residual, temperatura de transição vítrea, quantidade de agente de expansão incorporado, massa específica, razão de expansão, diâmetro médio e dispersão dos diâmetros das gotas de água incorporada e, finalmente, a dimensão média e dispersão das células formadas após a expansão. Foi avaliada a influência do uso de um agente reticulante já empregados no caso do EPS convencional. O material foi obtido em ampliação de escala e em reatores sem semelhança geométrica, e os resultados foram reproduzidos quanto à incorporação de água e estrutura celular bem como para o peso molecular e grau de conversão. O comportamento do material e as propriedades determinadas mostram que a técnica de produção implementada foi eficaz e sugerem que o uso de água como agente de expansão é uma alternativa viável

Development of dairy beverages functionalized with pure ergosterol and mycosterol extracts: an alternative to phytosterol-based beverages

In the present work, Agaricus bisporus extracts obtained by ultrasound-assisted extraction (UAE), and ergosterol, were incorporated into dairy beverages at concentrations mimicking commercial phytosterol-added yogurts, to work as alternatives. The samples were analysed for nutritional and bioactive properties, and compared with controls (yogurts with no additives or phytosterols), at two storage times (right after incorporation (ST = 0) and after seven days at 4 °C (ST = 7)). The ones incorporated with the extract (YAb) and with ergosterol at the same concentration as in the extract (YPEAb) showed similar antioxidant properties as the ones with phytosterols (YPhy), but a higher cytotoxicity against tumor cells. YPEPhy, the sample with ergosterol at the same amount as phytosterols in YPhy, was the strongest in both bioactivities. For YAb, YPEAb and YPEPhy the antioxidant capacity increased from ST = 0 to ST = 7, meaning that the extract and ergosterol protected the yogurt from oxidation, improving the shelf life. Nutritional parameters were identical for all samples.The authors acknowledge FCT (Portugal) for financial support to (UID/AGR/00690/2013), Sandrina A. Heleno (SFRH/BPD/101413/2014), L. Barros (SFRH/BPD/107855/2015) and R.C. Calhelha (SFRH/BPD/BPD/68344/2010); POCI-01-0145-FEDER-006984 (LA LSRE-LCM), funded by FEDER, through POCI-COMPETE2020 and FCT; Project NORTE-01-0145-FEDER-000006.info:eu-repo/semantics/publishedVersio

Heat and pH stable curcumin-based hydrophylic colorants obtained by the solid dispersion technology assisted by spray-drying

Natural food colorants are on demand due to food safety concerns related with some synthetic counterparts. Health-friendly alternatives can be available from plant sources, which include curcumin extracted from Curcuma longa L. However, its industrial use is difficult to achieve due to the low water affinity, pH and thermal instability, which is particularly challenging, e.g. for baked foods. In this work, the solid dispersion technique followed by spray-drying, an emergent approach in the context of colorants, was applied to curcumin using k-carrageenan, poly(vinyl alcohol) and polyvinylpyrrolidone, as the encapsulant materials. An orthogonal central composite design with dummy-variables was applied, and principal component analysis (PCA) and hierarchical cluster analysis (HCA) carried out to identify the experimental conditions leading to the most effective formulations. In general, particles with a wide range of pH and heat stability have been produced depending on the chosen encapsulant material, used formulation (curcumin, surfactant and polymer contents), and synthesis conditions (pH). Moreover, the used mathematical approach showed to be a valuable tool to support the development of tailor-made formulations directed to specific applications where pH and temperature are relevant processing parameters.This work was financially supported by Associate Laboratory LSRE-LCM (UID/EQU/50020/2019) funded by national funds through FCT/MCTES (PIDDAC), and Foundation for Science and Technology (FCT, Portugal). CIMO (UID/AGR/00690/2019) through FEDER under Program PT2020. Authors thank CAPES (Brazil), CNPq (Brazil) and Fundação Araucária (Brazil) for the support.info:eu-repo/semantics/publishedVersio

Microencapsulation of ergosterol and Agaricus bisporus L. extracts by complex coacervation using whey protein and chitosan: Optimization study using response surface methodology

In the present work microencapsulation was applied to an ergosterol enriched extract (EEE) from Agaricus bisporus L. and pure ergosterol (PE) using a complex coacervation process. The process was optimized following two steps: (i) using response surface methodology to optimize the conditions of temperature (T, 55 to 95 °C), protein-to-chitosan ratio (P/C, 0.5 to 10.5), maximizing yield (Y1, %, w/w), efficiency (Y2, %, w/w) and load (Y3, %, w/w); and (ii) using the dose-response methodology to optimize the ergosterol content (E) at the optimal conditions achieved in (i). The global optimal conditions for both cases were the same (T of 55 °C and a P/C of 0.5), but with maximized responses of Y1=75.02%; Y2=100.00%, Y3=12.78%, and Y1=19.19%; Y2=100.00%, Y3=15.87%, respectively. The effect of increasing ergosterol content led to the reduction of the microencapsulation yield, but with an increase in the ergosterol load and maintenance of the microencapsulation efficiency.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), to European Structural and Investment Funds (FEEI) through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®, Sandrina A. Heleno (SFRH/BPD/101413/2014), L. Barros (SFRH/BPD/107855/ 2015) and Xunta de Galicia for financial support for the post-doctoral researcher of M.A. Prieto; POCI-01-0145-FEDER-006984 (LA LSRE LCM), funded by FEDER, through POCI-COMPETE2020 and FCT; Project NORTE-01-0145-FEDER-000006.info:eu-repo/semantics/publishedVersio

Tailoring swelling of alginate-gelatin hydrogel microspheres by crosslinking with calcium chloride combined with transglutaminase

lginate-based hydrogels can find uses in a wide range of applications, including in the encapsulation field. This type of hydrogels is usually ionically crosslinked using calcium sources giving rise to products with limited internal crosslinking. In this work, it is hypothesized that the combination of alginate crosslinked by calcium chloride (external crosslinking; ionic mechanism) with gelatin crosslinked by transglutaminase (internal crosslinking; enzymatic induced mechanism) can be used to tailor the swelling behavior of alginate-based hydrogel microspheres. A systematic study was conducted by covering process variables such as gelatin content, TGase concentration, and CaCl2 contact time, added by statistic tools as central composite rotatable design (CCRD), principal component analysis (PCA) and multiobjective optimization, to map their effect on the resulting water content after production (expressed as swelling ratio), and swelling properties at pH 3 and 7. Among the studied variables, particle's swelling was mostly affected by the gelatin content and transglutaminase concentration.This work was financially supported by Associate Laboratory LSRELCM (UID/EQU/50020/2019) funded by national funds through FCT/ MCTES (PIDDAC), and Foundation for Science and Technology (FCT, Portugal) and by CIMO (UID/AGR/00690/2019) trough FEDER under Program PT2020. The authors are grateful to CAPES, CNPq and Fundação Araucária for the support and also to Ajinomoto Foods Europe S.A.S. (France) for kindly provide the transglutaminase sample used in this work. I.P. Fernandes thanks the national funding by FCT, P.I., through the institutional scientific employment program-contract for her contract.info:eu-repo/semantics/publishedVersio

Chemometric evaluation of enzymatic hydrolysis in the production of fish protein hydrolysates with acetylcholinesterase inhibitory activity

Fish protein hydrolysates (FPH) obtained from industrial processing residues are sources of bioactive peptides. The enzymatic hydrolysis process is essential in obtaining specific bioactivities such as inhibition of the enzyme acetylcholinesterase (AChE). In this study the effect of different hydrolysis conditions on the properties of FPH to inhibit the enzyme acetylcholinesterase. A chemometric evaluation, based on a central composite rotatable design and principal component analysis, was applied to select hydrolysis conditions with best yield, degree of hydrolysis and acetylcholinesterase inhibition. Experimental design results for AChE inhibition were between 10.51 and 40.45% (20, 30 and 50 mg.mL-1 of FPH), and three hydrolysis conditions were selected based on PCA evaluation. The amino acids profile, FTIR and AChE inhibition kinetics were evaluated. Results showed a mixed type of inhibition behavior and, the docking molecular analyzes suggest that the inhibition AChE occurred due to the basic amino acids, mainly by arginine.Authors thank to CNPq (Chamada Universal– MCTI/CNPq N◦ 28/2018, Process 421541/2018-0) and Fundação Araucária (convênios 40/2016, 53/2019 and 039/2019) for the financial support. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Authors thank to Central Analítica Multiusu´ario da UTFPR Campo Mour˜ao (CAMulti-CM) by the analysis.info:eu-repo/semantics/publishedVersio

Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acid

Mushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC 50 values: 214 and 272 mg.mL −1 ) that decreased after 7 days (EC 50 values: 248 and 314 mg.mL −1 ). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC 50 values, 0 days: 106 mg.mL −1 ; 7 days: 48.7 mg.mL −1 ), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties.This work was financially supported by: Project POCI-01-0145-FEDER-006984 – Associate Laboratory LSRE-LCM funded by FEDER through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT – Fundação para a Ciência e a Tecnologia. The authors are also grateful to FCT and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013), S. Heleno grant (SFRH/BPD/101413/2014) and L. Barros, J. Barreira and C. Calhelha contracts. To Norte 2020, through FEDER e FSE under PT2020 (Projeto NORTE-01-0145-FEDER-000006). To FEEI through NORTE 2020 (Project ValorNatural®). To CAPES (Brasil) (Project 99999.000488/2016-00, Strategic programs -DRI).info:eu-repo/semantics/publishedVersio

Chemometric approaches to evaluate the substitution of synthetic food dyes by natural compounds: The case of nanoencapsulated curcumin, spirulina, and hibiscus extracts

Finding natural food coloring options from plant-based sources to substitute artificial dyes is a challenging task because natural dyes often present low water-solubility, not very vibrant hues, and instability due to interactions with food ingredients. Chemometric approaches can be used to evaluate color differences and patterns resulting from natural and synthetic dyes when applied to food systems. Here, the Mixture Design and the Principal Component Analysis (PCA) were applied to evaluate the substitution of the following artificial food dyes: yolk yellow, apricot yellow, strawberry red, and tartrazine by natural dyes (water-soluble curcumin, yellow shade; Hibiscus sabdariffa extract, red shade; Spirulina platensis extract, blue/green shade), in three food simulated systems (phosphate buffer, pH 6.9; yogurt, pH 4.0 and citrate buffer, pH 3.0). The color parameters L*, a*, b*, C* and °h were determined and color difference (ΔE*) with artificial dyes resulted in 11 empirical models. PCA yielded a clear map for the identification of the closely matches natural/artificial dyes for the food simulated systems in three subregions. Furthermore, the antioxidant capacity of the natural dyes was determined by OxHLIA and TBARS. It was possible to make an assessment guide that may be useful for other food systems and dyes.Authors thank to CNPq (Chamada Universal– MCTI/CNPq Nº 28/2018, Process 421541/2018–0) and Fundação Araucária (convênio 039/2019) for the financial support. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. Authors thank to Central Analítica Multiusuário da UTFPR Campo Mourão (CAMulti-CM) by the color analysis. Authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to the CIMO (UIDB/00690/2020). L. Barros and C. Pereira thank the national funding by FCT, P.I., through the institutional scientific employment program-contract for their contracts.info:eu-repo/semantics/publishedVersio

β-Carotene colouring systems based on solid lipid particles produced by hot melt dispersion

In this work, β-carotene was selected to develop a novel study, namely a food colorant system based on beeswax solid lipid particles obtained by hot melt dispersion. The obtained microparticles were characterized by optical microscopy, scanning electron microscopy, particle size analysis and Fourier Transform Infrared spectroscopy. It was observed that the obtained size can be modulated by using different amounts of emulsifier, as well as the dispersing capability. In a final stage, the obtained particles were tested concerning their colorant power by selecting a food matrix widely appreciated and consumed (mayonnaise). Moreover, the formulation providing the best hue and dispersibility (formulation containing 3% of Tween 80, and β-carotene at 5 mg/25 g of commercial mayonnaise) was analysed along a storage period of 15 days concerning colour, nutritional value and chemical composition. The results pointed out for colour stability and nutritional value maintenance, after 15 days under storage at 6 °C.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UIDB/00690/2020), and to UIDB/50020/2020 of the Associate Laboratory LSRE-LCM - funded by national funds through FCT/MCTES (PIDDAC); national funding by FCT, PI, through the institutional scientific employment program-contract for L. Barros’s and I. Fernandes contract; to the project AllNat for the contract of C. Caleja (Project AllNat POCI-01-0145-FEDER-030463), the Valor Natural project for the contract of E. Pereira (Mobilized Project Norte-01-0247- FEDER-024479), and FCT for the PhD research grant SFRH/BD/147326/2019 (S.C. Rezende). This work is also funded by the European Regional Development Fund (ERDF) through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01- 0247-FEDER-024479: ValorNatural®; and to FEDER-Interreg España- Portugal programme for financial support through the project TRANSCoLAB 0612_TRANS_CO_LAB_2_P.info:eu-repo/semantics/publishedVersio