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This study aimed to produce soluble potato starch ultrafine fibers for the encapsulation of pinhao coat extract (PCE), evaluating their relative crystallinity (RC), thermal stability, antioxidant activity, antimicrobial activity against Escherichia coli and Staphylococcus aureus, as well as in vitro biological digestion. In the simulation of in vitro biological digestion, the phenolic compounds release profile was also evaluated. The ultrafine fibers were produced by electrospinning, based on a polymeric solution composed of soluble potato starch (50% w/v) and formic acid. Then, PCE was incorporated at various concentrations (0.5%, 1.0%, and 1.5%, w/w, dry basis). The endothermic event of free PCE was not observed in the ultrafine fibers, which suggests its encapsulation. The RC decreased according to the increase in PCE concentration in the ultrafine fibers. The PCE resisted thermal treatments when encapsulated into the ultrafine fibers (100 and 180°C), and the ultrafine fibers with 1% PCE presented the highest amount of preserved phenolic compounds. Regarding antioxidant activity, the free PCE presented 85% of DPPH inhibition and the ultrafine fibers had 18% inhibition, not differing among the PCE concentrations (p

BACKGROUND The supplementation of folic acid in food is essential in the human diet. The present study aimed to encapsulate folic acid at different concentrations (5, 10 and 15% (w/w) on a dry basis) in potato starch nanofibers produced through electrospinning. The starch/folic acid nanofibers were evaluated through morphology, Fourier transform infrared (FTIR) spectra, thermal properties, encapsulation efficiency (EE) and in vitro simulation of the human digestion. The nanofibers were also evaluated based on the folic acid content after thermal treatment (100 and 180 °C) and UVA irradiation (1 and 24 h). RESULTS Folic acid incorporation influenced the morphology of the nanofibers to display a homogeneous and beadless morphology for nanofibers containing 15% folic acid compared with the other nanofibers (0, 5 and 10% folic acid). The mean diameter varied from 75 to 81 nm. Folic acid characteristic bands and peaks were not found in the nanofiber FTIR spectra and thermograms, respectively. The EE was 73, 87 and 95% for nanofibers with 5, 10 and 15% folic acid, respectively. CONCLUSIONS The starch nanofibers protected folic acid from high temperature and UVA irradiation and during in vitro digestion, showing a release of the vitamin at the end of the simulation (intestinal conditions). The supplementation of folic acid in foods can be effectively achieved by its encapsulation into starch nanofibers, to ensure its protection and controlled release. © 2020 Society of Chemical Industry.

In this study, a method was developed to encapsulated carvacrol in nanofibers from soluble potato starch. The carvacrol was added in starch solutions at various concentrations (0, 20, 30 and 40% v/v) and electrospun into fibers. The morphology, size distribution, thermal stability, FT-IR spectra, relative crystallinity (RC) and antioxidant of the electrospun fibers were analyzed. For mechanical properties and antimicrobial activities evaluation electrospun nonwovens were obtain. The carvacrol-loaded nanofibers showed homogeneous morphology and average diameters ranging from 73 to 95 nm. The carvacrol encapsulated in the nanofibers had greater thermal stability than the free carvacrol. FT-IR analysis showed interactions between starch and carvacrol. The RC of the nanofibers was approximately 40%. The electrospun nonwovens mechanical properties did not present significant differences (p 0.05). The 40% carvacrol-loaded nanofibers exhibited higher antioxidant activity with 83.1% of inhibition. The electrospun nonwoven loaded with 30% carvacrol resulted in 89.0% reduction of Listeria monocytogenes, 68.0% for Salmonella Typhimurium, 62.0% for Escherichia coli and 49.0% for Staphylococcus aureus. These electrospun nonwovens sustained antimicrobial activity for at least 30 days against S. aureus. The starch nanofibers are promising materials for application as a vehicle for carvacrol release in antimicrobial and antioxidant food packages.

The objective of this study was to immobilize α-amylase in ultrafine polyvinyl alcohol (PVA) fibers by electrolysis and to evaluate its stability at different temperatures and pHs using various starch substrates such as corn starch and germinated and ungerminated wheat starches. The α-amylase-loaded ultrafine fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and loadability and enzymatic activity evaluations. Incorporation of the enzyme resulted in a slight change in fiber morphology; the fibers became flatter and thicker with increasing enzyme concentration. The mean diameters ranged from 187 to 282 nm. FT-IR spectra indicated that the enzyme was incorporated into the fibers. PVA showed a high loading capacity for α-amylase at all concentrations tested (1.0, 1.5, and 2.0% w/v), indicating that PVA is an excellent support. The enzymatic activity of α-amylase was tested on the different starch substrates; the activity was higher in the immobilized form than in the free form. Enzymatic immobilization improved the stability of α-amylase over a wide range of temperatures and pHs. Enzymatic activity was highest when germinated wheat starch was used as the substrate at different temperatures and pHs, indicating great potential for its application in hydrolysis with α-amylase.

Through starch phosphorylation and solution aging treatments, the aim of this work was to produce electrospun fibers derived from native and anionic (modified with sodium tripolyphosphate) corn starches with amylose contents of

The ultrafine fibers were produced using a polymeric blend of soy protein isolate (SPI), polyethylene oxide (PEO), and zein at a ratio of 1:1:1 (v/v/v) by electrospinning. The ginger essential oil (GEO) was encapsulated in the ultrafine fibers and the morphology, Fourier-Transform Infrared Spectroscopy (FTIR) analysis, thermal properties and relative crystallinity were evaluated. The antimicrobial activity of ginger essential oil was evaluated against five bacteria (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli 0157:H7, Salmonella typhimurium, and Pseudomonas aeruginosa). Based on the preliminary tests, the concentration of GEO selected to add in the polymer solution was 12% (v/v; GEO/polymer solution). The fiber produced with 12% (v/v) GEO was used for antimicrobial analysis and in situ application (in fresh Minas cheese) against L. monocytogenes by micro-atmosphere. The ultrafine fibers produced, regardless the concentration of the essential oil, presented homogeneous morphology with cylindrical shape without the presence of beads. The application of the active fibers containing 12% GEO showed high potential to be applied in food packaging to reduce microbial contamination.

Background Thyme essential oil (TEO) is an excellent natural substitute for synthetic compounds to maintain the quality and safety of food products. It acts as an antioxidant agent. We aimed to nanoencapsulate TEO at concentrations of 1%, 3%, and 5% (v/w, dry basis) in electrospun nanofibers made of starch (50% w/v) and formic acid (75% v/v). The rheological parameters of the fiber-forming solutions were measured, and various physical and chemical properties of the nanofibers were analyzed. Results The starch/TEO nanofibers presented homogeneous morphology. The starch nanofibers showed high encapsulation efficiency (EE, 99.1% to 99.8%), which, along with the Fourier transform infra-red (FTIR) spectrum and thermogravimetric analysis (TGA) analysis, indicate strong protection of the phenolic compounds of TEO. Nanofibers with 5% TEO retained up to 50% of the phenolic compounds after exposure to thermal treatment. The antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals of the starch/TEO nanofibers varied from 11.1% to 14.2% and the inhibition values (29.8%, P ≤ 0.05) against hydroxyl radicals were the same for free TEO and the nanofibers. Conclusion Owing to these properties, electrospun starch/TEO nanofibers can be applied in food products or food packaging.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2020-08-24T23:01:02Z No. of bitstreams: 1 TESE_Laura_Martins_Fonseca.pdf: 7918957 bytes, checksum: 3fb74701dcd38a639b0b8635d668ab24 (MD5) Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2020-08-25T01:24:21Z (GMT) No. of bitstreams: 1 TESE_Laura_Martins_Fonseca.pdf: 7918957 bytes, checksum: 3fb74701dcd38a639b0b8635d668ab24 (MD5) Made available in DSpace on 2020-08-25T01:24:21Z (GMT). No. of bitstreams: 1 TESE_Laura_Martins_Fonseca.pdf: 7918957 bytes, checksum: 3fb74701dcd38a639b0b8635d668ab24 (MD5) Previous issue date: 2020-02-04 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES Nanofibras de amido produzidas por electrospinning são efetivas na encapsulação de compostos bioativos, gerando materiais biodegradáveis aplicáveis na elaboração de embalagens ativas para alimentos. Estas embalagens interagem com os alimentos, aumentando sua vida útil, como as antimicrobianas que retardam o crescimento de microrganismos deteriorantes ou patogênicos em alimentos, ou ainda, as com atividade antioxidante que retardam as oxidações ocorrentes no armazenamento. Nesse contexto, objetivou-se com o estudo produzir nanofibras a partir de amido de diferentes fontes (milho e batata) com diferentes teores de amilose, nativos ou modificados, e incorporá-las com carvacrol visando a produção de um material com atividades antimicrobiana e antioxidante. A tese está subdividida em três capítulos, sendo no primeiro produzidas nanofibras de amido de milho nativo e aniônico, ambos com diferentes teores de amilose. No segundo foi estudada a produção de nanofibras de amido de batata solúvel com diferentes tempos de descanso da solução polimérica formadora de nanofibras. Por fim, no terceiro capítulo foram produzidas nanofibras de amido de batata para encapsulação de carvacrol e avaliação de suas atividades antimicrobiana e antioxidante. Nos capítulos 1 e 2 as nanofibras foram produzidas e avaliadas quanto às suas propriedades morfológicas, estruturais e térmicas. As nanofibras de amido de batata solúvel apresentaram-se contínuas, com diâmetros na ordem de nanômetros e alta estabilidade térmica (Capitulo 2). Assim, foram escolhidas para encapsulação de carvacrol (Capítulo 3). As nanofibras de amido/carvacrol apresentaram alta atividade antioxidante frente ao radical ABTS e antimicrobiana reduzindo o crescimento de L. monocytogenes, S. Typhimurium, E. coli e S. aureus e ainda mantendo sua atividade antimicrobiana frente a S. aureus por 30 dias. Assim, mostrando potencial para serem aplicadas na conservação de alimentos pela formação de embalagens ativas. Electrospun nanofibers are effective in encapsulating bioactive compounds, generating biodegradable materials applicable as active packaging for food products. These packages interact with food, increasing its shelf life, such as antimicrobials that prevent the growth of deteriorating or pathogenic microorganisms in food. As well as those packages with antioxidant activity that delay oxidations during storage. In this context, the aim of the study was to produce and characterize nanofibers from starch from different sources (corn and potato) with different amylose contents, native or modified. Furthermore, to incorporate the nanofibers with carvacrol aiming at the production of an antimicrobial and antioxidant material. The thesis is divided into three Chapters: First, nanofibers of native and anionic corn starch were produced, both with different amylose contents. In the second chapter, the production of potato starch nanofibers with different aging times of polymeric fiber-forming solution was studied; Finally, in the third chapter, potato starch nanofibers were produced to encapsulate carvacrol and evaluate its antimicrobial and antioxidant activities. In Chapters 1 and 2, the nanofibers were produced and evaluated for their morphological, structural and thermal properties. The soluble potato starch nanofibers were continuous, with diameters in the order of nanometers and high thermal stability (Chapter 2). Thus, they were chosen for the encapsulation of carvacrol (Chapter 3). The starch/carvacrol nanofibers showed high antioxidant against ABTS radical and antimicrobial activity, reducing the growth of L. monocytogenes, S. Typhimurium, E. coli and S. aureus and maintaining their antimicrobial activity against S. aureus for 30 days. The nanofibers showed potential to be applied in food products conservation through the formation of active packages.

BACKGROUND Yerba mate extract was encapsulated in electrospun zein fibers. Solutions were prepared with 30% (w/v) zein, and yerba mate extract was added at concentrations of 1%, 3%, and 5% (w/w). The rheology and electrical conductivity of the polymer solutions were evaluated. The extract and the fibers were characterized through an analysis of total and individual phenolic compounds, antioxidant activity, and Fourier-transform infrared (FTIR) spectra. Morphology, size distribution, and thermal stability were also evaluated. The release kinetics of zein fibers loaded with different concentrations of yerba mate were evaluated in a hydrophilic food-simulant medium (10% ethanol). RESULTS Yerba mate extract had a total phenolic compound content of 1287.76 ± 11.55 mg of gallic acid 100 g-1 yerba mate extract. The major individual phenolic compounds obtained were chlorogenic acid and rutin, quantified by high-performance liquid chromatography and mess spectrometry (HPLC-MS). Zein fibers loaded with 5% extract exhibited higher antioxidant activity with 83.0% inhibition. The fibers with different concentrations of yerba mate displayed homogeneous morphology. Yerba mate extract encapsulated in zein fibers had greater thermal stability than the free extract. Zein fibers comprising 5% yerba mate extract, when in contact with a hydrophilic food simulant medium, showed a release of approximately 49% of extract within 50 h. CONCLUSION Zein fibers containing yerba mate extract may be used as antioxidant releasers for food packaging. © 2020 Society of Chemical Industry.

This study is focused on the production of zein-TiO2 nanofibers produced through electrospinning and the evaluation of such fibers as ethylene absorbers when used to improve the storage of cherry tomatoes. Zein (30 % (w/v)) were dissolved in 70 % (v/v) ethanol and incorporated with TiO2 (0 %–5 %). The polymer solutions were evaluated for their electrical conductivity and viscosity, and the nanofibers were evaluated for their morphology, size distribution, thermal properties, Fourier transform infrared and water contact angle. The nanofibers with the smallest diameter were selected for testing as ethylene absorbers in the storage of cherry tomatoes for 22 days. The addition of TiO2 reduced the diameter of the nanofibers and altered their thermal properties. Interactions between the zein and TiO2 were observed based on the infrared spectrum. Containers with sachet of nanofibers exhibited a lower concentration of ethylene, demonstrating their significant potential for use as an active food packaging.