Search

The attention towards active films has increased due to consumer demand for high-quality foods without chemical additives. Active biopolymer-based films have shown great potential for active films by impacting food safety, acting as the carriers of various natural antioxidant and antimicrobial compounds, and decreasing environmental pollution from petrol-derived packaging materials. However, there is a wide range of challenges concerning the different characteristics of biopolymers and plasticizers, often hygroscopic/hydrophilic, compared to numerous lipophilic bioactive compounds. Therefore, recent studies have focused on applying oil-in-water emulsion-based systems to enhance the lipophilic bioactive compounds' dispersibility into the film matrix, improving their performance. It is worth emphasizing that resulting complex systems give rise to new challenges such as (i) dispersion technology of the bioactive compounds with minimum adverse effects on its bioactivities, (ii) interactions between different components of the active films, giving rise to new physicochemical properties, and (iii) the change of the diffusion properties of bioactive compounds into the active films, resulting in different release properties. These challenges are profound and critically discussed in this review, as well as the encapsulation techniques employed in preparing emulsions loaded with lipophilic bioactive compounds for the active film development. An outlook of future directions in the research, development, and application of these active films are given.

Active films have gained increasing interest because of their potential to reduce the amount of additives into foods. The aim of this work was to produce and characterize bi-layer films based on gelatin in both layers, in which the nisin and/or “pitanga” leaf hydroethanolic extract was loaded in the second layer. The bi-layer gelatin-based films were characterized regarding humidity and solubility in water, color, microstructure, mechanical properties, water contact angle, water vapor permeability, UV/Vis barrier, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and antimicrobial and antioxidant activities. The addition of active compounds on the second layer of the films was sufficient to produce active films. The presence of additives in the films’ second layer did not affect film humidity, water vapor permeability, or the molecular interactions of the polymer matrix as assessed by FTIR. Although some mechanical properties and the water contact angle were affected, it was not necessarily deleterious to the films’ functionality. All active films presented activity against Staphylococcus aureus and Listeria monocytogenes even with the additive being present only in a thin layer. And, as it could be expected, only films containing PLHE presented antioxidant activity. This study concluded that the bi-layer technique permits the production of active films while employing only one third of the amount of additives when compared to similar monolayer films of the same thickness, as produced in a previous work.

Processed meat products have been increasingly consumed, a highlight being dried-cured coppa, commonly purchased sliced, making it more susceptible to bacterial deterioration and lipid oxidation. The aim of this work was to produce and apply bi-layers films based on gelatin (in both layers) with addition of nisin and/or Pitanga leaf hydroethanolic extract (PLHE) only in the food contact thinner layer, in order to evaluate their effect on the refrigerated storage of sliced dried-cured coppa. Dried-cured coppa slices covered with active films were vacuum-packaged and stored under refrigeration for 120 days. Every 30 days, samples were tested for moisture content, water activity, pH, color parameters, lipid oxidation by TBARS and peroxide index methods, and microbiological analysis. The different film formulations presented no influence on the water activity, pH and color parameters of sliced dried-cured coppa. However, they significantly affected moisture content, bacterial count and lipid oxidation. The addition of both active compounds - nisin and PLHE - in the food contact thinner layer was observed to have the most favorable effect.

The aim of this study was to evaluate the effect of the incorporation of water-in-oil-in water (W/O/W) double emulsion (DE) loaded with “pitanga” leaf hydroethanolic extract on the physicochemical, antimicrobial and antioxidant properties of films based on gelatin, chitosan and gelatin/chitosan blend to target the future application of these films as active food packaging. Scanning electron microscopy and atomic force microscopy images of the films showed that the presence of DE caused heterogeneity on the surface and internal structure. As a consequence, the decrease in the gloss and the water drop contact angle of films was caused mainly by the increase in surface roughness. In addition, the DE significantly improved the UV/Vis light barrier property of the films. The DE increased the strength and stiffness of the films based on gelatin and chitosan, but decreased those properties in the gelatin/chitosan blend, and increased the extensibility of all films, in addition to decreasing water solubility, water vapor permeability and opacity. Films with DE showed high antioxidant activity, but only the films based on gelatin and with DE inhibited Staphylococcus aureus. The other films containing DE inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella ssp bacteria just in the region of contact with the films.

Natural additives to extend food shelf-life has gain importance because consumers aim at acquiring health and wellness from food products without synthetic additives. The utilization of plant additives, mainly herbs and spices extracts, can be an alternative to replace synthetic additives in meat products. Nevertheless, extracts from less conventional plants, such as Pitangueira (Eugenia uniflora) has attracted attention due to its bioactive properties. Thus, in this work, the utilization of pitangueira leaf extracts (PLE) as alternative to traditional additives in fresh pork sausage was described. Procedures to improve the quantity of bioactive compounds in the extracts were described, and fresh pork sausages formulations with natural and/or traditional synthetic additives were prepared and assessed for their physical-chemical properties during 12 days, at 4 °C. Before presenting some experimental results, a brief review on pork quality, chemical additives used in processed pork, and plant bioactive compounds was presented. After that, some important experimental data on production of PLE and its characterization regarding cytotoxicity, antioxidant and antibacterial activities were presented. At the end, some data from experiments on conservation of a fresh sausage based on pork meat additive with the PLE, stored at 4 °C for 12 days, was also presented.

Atualmente, existe uma crescente preocupação e uma preferência por alimentos com reduzida incorporação de aditivos e com utilização de compostos naturais em substituição aos sintéticos. Assim, os filmes ativos a base de biopolímeros podem ser uma boa alternativa. Eles podem permitir uma maior vida de prateleira, garantindo a segurança alimentar, sem a incorporação direta de conservantes nos alimentos. O objetivo geral desta tese foi o desenvolvimento e a caracterização de filmes ativos a base de gelatina, com duas camadas, uma camada de gelatina sem aditivo, e uma segunda camada, mais fina, contendo os princípios bioativos: agente antioxidante (extrato hidroetanólico de folhas de pitangueira, EHFP) e/ou agente antimicrobiano (nisina ou natamicina). Especificamente, pretendeu-se estudar as atividades antioxidante e antimicrobiana dos filmes ativos dupla camada contendo EHFP com, e sem, nisina ou natamicina; estudar as propriedades físicas desses filmes ativos dupla camada a base de gelatina; e aplicar um filme ativo selecionado, contendo EHFP e/ou nisina na segunda camada, na conservação da Copa fatiada. Os filmes ativos foram caracterizados para conhecimento do efeito dos aditivos na segunda camada, sobre suas propriedades físico-químicas, mecânicas, ópticas, microestruturais, térmicas e atividades antimicrobiana e antioxidante. A adição de nisina foi capaz de produzir filmes com atividade antimicrobiana, enquanto a adição do EHFP produziu filmes com atividade antioxidante e antimicrobiana. A adição de ambos aditivos conjuntamente não provocou efeito antagônicos, ou seja, os filmes apresentaram ambas as atividades. Em nenhum dos casos, houve prejuízos às propriedades físicas dos filmes. Por outro lado, a adição de natamicina também produziu filmes ativos contra os fungos estudados, no entanto, a natamicina mostrou um efeito maior nas propriedades físico-químicas dos filmes a base de gelatina quando comparado à nisina ou ao extrato. A adição conjunta do extrato com o agente antimicrobiano permitiu observar que não houve interação entre eles que pudesse diminuir ou inibir a ação de um dos compostos. Ou seja, esses filmes a base de gelatina incorporados com agentes ativos podem ser usados como um potencial material de embalagem ativa para aumentar a vida útil e a segurança dos alimentos. No estudo da aplicação dos filmes a base de gelatina contendo EHFP e nisina em Copa fatiada, pode-se comprovar a eficiência da incorporação de ambos aditivos na segunda camada do filme em contato com o alimento, na conservação do produto em estocagem a 4 °C por até 120 dias, comparado com o controle. Pode-se então concluir que foi possível desenvolver filmes ativos, com atividades antioxidante e antimicrobiana, com potencial aplicação na conservação de alimentos. Currently, there is a preference for foods with reduced incorporation of additives and with natural compounds to replace synthetic ones. Thus, biopolymer-based active films can be a good alternative, as they allow longer shelf life and ensure food safety without the direct incorporation of agents in food. The general goal of this thesis was the development and characterization of gelatin-based double-layer active films, the first layer of gelatin being free of additives, while the second (thinner one), contains the bioactive principles: antimicrobial agent (nisin or natamycin) and/or antioxidant agent (Pitanga leaf hydroethanolic extract, PLHE). Specifically, the goal was to study the antimicrobial and antioxidant activities of active double layer films containing nisin or natamycin, with and without PLHE, as well as the physical properties of these films; and to apply a selected active film, containing nisin and/or PLHE in the second layer, to preserve dry cured pork shoulder (coppa). The active films were characterized in order to determine the effect of additives in the second layer on their physical-chemical, mechanical, optical, microstructural, thermal and antimicrobial and antioxidant activities. The addition of nisin was proven to produce films with antimicrobial activity, while the addition of PLHE produced films with antioxidant activity. The addition of both additives together did not cause an antagonistic effect, that is, the films presented both activities. In none of the cases, damage to the physical properties of the films was observed. On the other hand, the addition of natamycin also produced films active against the studied fungi. However, natamycin showed a greater effect on the properties of gelatin films when compared to nisin or to the extract. In the case of joint addition of the extract and the antimicrobial agent, no interaction between them that could decrease or inhibit the action of one of the compounds was observed. That is, these gelatin films incorporated with active agents can be used as a potential active packaging material to increase the shelf life and safety of food. In the study of the application of gelatin films containing nisin and PLHE, in sliced coppa, it is possible to prove the efficiency of incorporating both additives in the second layer of the film in contact with the food in preserving the product in storage at 4 °C for up to 120 days. In conclusion, the possibility of developing active films, with antioxidant and antimicrobial activities, with potential application in food preservation was proven.

Starches are widely used in food processing, and their rheological properties are affected by thermal conditions imposed during the process. The objective of the present study was to assess the rheological behavior of jackfruit seed starch (JSS) dispersions, with a particular interest on the effects of the starch extraction techniques using either water or an alkali solution (0.1 M sodium hydroxide) as solvents. The analyses on the starches were performed using small amplitude oscillatory shear tests, including frequency, temperature, and time sweeps, and determining flow curves at different temperatures (10–40 °C). JSS dispersions were classified as weak-intermediary gels, and those prepared with JSS extracted with water showed higher values of G’ and G” in all of the tested samples. All gelatinized samples exhibited viscoelastic behavior, and with increasing temperatures the storage and loss moduli increased until a maximum value before reaching a plateau. Gelatinization temperatures were slightly lower for dispersions prepared with JSS extracted with water. Gelatinization kinetics showed that increasing temperatures caused a reduction in the time to achieve gelatinization. The JSS dispersions displayed thixotropic behavior, which was influenced by their concentration and the extraction method employed. The flow curves exhibited pseudoplastic behavior. The Power Law model was used to describe the JSS dispersions rheological behavior, which enabled to assess the effects of starch concentration and extraction method on their rheological properties.

The aim of this research was to study the effects of laponite concentrations on some properties of nano-biocomposite films based on cassava starch, focusing mainly the relation between the properties of the surface microstructure and roughness, water contact angle and gloss. Nano-biocomposite films were produced by casting. We analyzed gloss, color, opacity, water contact angle, crystallinity by X-ray diffraction, and microstructure by scanning electron microscopy and atomic force microscopy. Texture parameters (energy, entropy and fractal dimension) were extracted from micrographs. We observed a great impact of laponite in the morphology of nano-biocomposite films. Texture parameters correlated with surface heterogeneity and roughness. Finally, surface roughness affected the surface hydrophilicity of nano-biocomposite films. Laponite platelets were exfoliated and/or intercalated with amylose and amylopectin chains. This research reports new information on the effects of laponite concentrations on the morphological, optical and wetting properties of nano-biocomposite films aiming future industrial applications.

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.

The effect of Laponite (a synthetic clay) on the structure, thermal and water vapor barrier properties of nanocomposite gelatin films produced by casting with 0, 4.5 and 15% w Lap/w gelatin, was studied. X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis and Fourier transform infrared spectroscopy measurements were reported. The X-ray diffraction patterns showed dual crystalline structure of the films with collagen-type bundles of triple helices, intercalated inside clay platelets, increasing interlayer distances. Depending on the renaturation of triple-helices and Laponite content, the glass transition temperatures substantially decreased. The amount of helices decreased with Lap concentration, affecting the enthalpy of melting. The nanocomposite gelatin films showed improved thermal stability. Changes of water vapor permeability could be related to the presence of larger free volume of the coils and intercalated structures, facilitating water transfer through the film., 43 pages, 5 figures, 4 tables, supplementary information

The objective of the present study was to analyze the effects of laponite concentrations (CLap) on surface morphology and physical properties of nano-biocomposite films based on collagen loaded with laponite. Films microstructure, thickness, moisture content (MC), gloss, color, opacity, crystallinity, chemical structure, thermal and mechanical properties (MP), water vapor permeability (WVP), and the water contact angle (WCA) were determined. A considerable impact of CLap on the surface roughness of the nano-biocomposite films was observed, without effect on its thickness, MC, gloss, color, opacity, MP, WVP, and WCA results. Laponite platelets were exfoliated into collagen chains, provoking a reduction in helix-coil formation, leading to a decrease in the enthalpy melting values of the nano-biocomposite films. This research reports for the first time information regarding films based on collagen loaded with laponite with potential use as food packaging.

In the last years, new concepts for edible coatings have been developed as a response to the demands of modern society, as well as the industrial production trends toward fresh, safe, wholesome, mildly preserved, convenient and quality food products with a longer shelf life. In this way, smart and active edible coatings have been developed as food packaging for several products. Smart edible coatings are used to monitor and inform food conditions to consumers in real time whereas active edible coatings are used to increase the shelf life in foods. Smart and active edible coatings are manufactured using biopolymers as solid matrix to immobilize additives with specific properties (e.g. pH sensitive, antimicrobial and antioxidant properties, among others). Recently, layer-by-layer (L-b-L) technique has been used to manufacture composite edible coatings. This technique is based on the alternate deposition of different biopolymers which enhance the physicochemical properties and activity of smart and active edible coatings. This chapter reviews the state of the art with regard to the use of L-b-L technique as well as the use of additives (including nanoparticles) to manufacture smart and active edible coatings. Especially, this chapter include information about the use of biopolymers for producing edible coatings by L-b-L; the use of additives (biological and synthetic) and nanoparticles to manufacture smart and active edible coatings, as well as prospects and limitations in smart and active edible coatings.

O amido é um ingrediente com grande versatilidade de aplicação, e as sementes de jaca, fruto bem difundido, porém pouco aproveitado no Brasil, contêm uma quantidade considerável de amido, sendo ainda fonte de ferro e proteínas. Dessa maneira, os objetivos desse projeto foram a obtenção da farinha de sementes de jaca das variedades mole e dura, a extração do amido utilizando diferentes solventes, e a caracterização de suas propriedades físico-químicas, estruturais e funcionais, bem como a caracterização reológica de dispersões/géis de amido em cisalhamento estacionário e oscilatório. A extração alcalina do amido, além de reduzir significativamente o conteúdo de lipídeos e proteínas, deixando o amido mais puro, promoveu um aumento no teor de amilose e influenciou diretamente as características de inchamento e solubilidade, que apresentaram aumento significativo a partir da temperatura de 70 °C. O aumento da temperatura ocasionou aumento no poder de inchamento e solubilidade, que foi mais pronunciado para a variedade dura, porém esses valores ainda foram considerados baixos (< 17%). Os amidos de sementes de jaca apresentaram grânulos lisos, arredondados e em forma de sino, com formato mais truncado para o amido extraído com hidróxido de sódio. O diâmetro médio dos grânulos de amido foi menor para a extração alcalina, mas sempre com comportamento monomodal. Foi observado um padrão de difração de Raios-X do tipo A para todas as amostras estudadas, e o índice de cristalinidade foi maior para os amidos de sementes de jaca dura, com uma redução estimada em 70% para os amidos obtidos por extração alcalina. A temperatura de gelatinização dos amidos de semente de jaca foi considerada alta (70-100 °C). Os amidos de sementes de jaca dura obtidos na extração com água apresentaram maiores valores de viscosidade de pico e de Breakdown, que representa menor resistência mecânica. A extração com solução de NaOH 0,1 M aumentou a tendência a retrogradação de ~36% (extração aquosa) para 64% e 45% dos amidos de sementes de jaca das variedades mole e dura, respectivamente. Todas as amostras apresentaram comportamento pseudoplástico (n < 1) nas concentrações e temperaturas estudadas, e as dispersões e/ou géis de amido obtidos pela extração alcalina com NaOH apresentaram menor tixotropia e maiores valores de viscosidade. Os modelos Lei da Potência e Herschel Bulkley apresentaram ótimos ajustes aos pontos experimentais (R² ~0,998) para as amostras com 2 e 6 % de amido, respectivamente, porém para a concentração de 5%, o melhor modelo foi função da variedade do fruto usado na obtenção do amido. A dependência das propriedades reológicas com a temperatura foi analisada pela equação de Arrhenius e a energia de ativação foi baixa (15-25 kJ/mol). Quanto ao comportamento viscoelástico, as amostras com 5 e 6% de amido apresentaram comportamento de gel fraco e o aumento da concentração desse polissacarídeo produziu um aumento na elasticidade do material. Os módulos de armazenamento (G\') associados à elasticidade do gel de amido aumentaram durante o seu resfriamento nos ensaios de varredura de temperatura, o que pode ser relacionado à recristalização da amilose durante esse processo e mantiveram-se praticamente constantes no aquecimento isotérmico a 80 °C, sugerindo boa estabilidade térmica do gel. A farinha isolada da semente de jaca pode ser considerada fonte de fibras e apresentou elevados teores de proteínas (~14-16%) e ferro (~85-150 mg/kg). A distribuição do tamanho de partículas da farinha apresentou comportamento bimodal, com grânulos arredondados, presença de fibras e uma matriz proteica envolvendo os grânulos de amido. As propriedades de pasta revelaram maior pico de viscosidade para a farinha de semente de jaca mole. As características encontradas sugerem que os amidos de semente de jaca poderiam ser aplicados na produção de filmes biodegradáveis, e a farinha da semente de jaca poderia ser utilizada em substituição parcial à farinha convencional na fabricação de bolos e biscoitos. Starch is an ingredient with great versatility of application, and the seeds of jackfruit, a well spread fruit but little exploited in Brazil, contain a considerable amount of starch, being a source of iron and proteins. Thus, the aimes of this project were to obtain the jackfruit seed flour of hard and soft varieties, extraction of starch using different solvents and characterization of its physicochemical, structural and functional properties, as the rheological characterization of dispersion/gels starch under steady and oscillatory shear. Alkaline extraction of starch significantly reduced the content of lipids and proteins, leaving to a purest starch, and promoted an increase in amylose content, besides, directly influenced the swelling and solubility characteristics, which showed a significant increase from the temperature of 70 ° C. The increase in temperature caused an increase in the power of swelling and solubility, which was more pronounced for the hard variety, but these values are still considered low (

Two main varieties of jackfruit (soft and hard) are commonly known in Brazil and contain a large amount of starch. This work aimed to evaluate the effect of extraction methods (aqueous and alkaline treatments) on the structural and physicochemical properties of starches from soft and hard jackfruit (Artocarpus heterophyllus) seeds. The jackfruit seed starch (JSS) granules were small (6.4–11.1 μm diameter), round, and bell-shaped with a smooth surface. Apparent amylose content ranged from 24 32% and was higher for the soft variety, which influenced several properties. The starches exhibited A-type XRD patterns, which contributed to the high peak gelatinization temperatures (72–81 °C), and a crystallinity index ranging between 9.3–36.9%. Peak viscosities (2362–3373 cP) were similar to cassava starch. However, irrespective of the extraction method, the hard JSS had relatively higher pasting properties (peak viscosity and breakdown), swelling power, and solubility index (90 °C) when compared to the soft JSS, which could be associated with the lower amylose content. Significant differences in lipid, protein, and amylose contents were observed in all starches extracted with the NaOH solution. The alkaline solvent decreased the average particle size of JSS by about 36%, probably causing a chemical gelatinization. Additionally, NaOH significantly reduced the crystallinity index and caused minor changes in granule morphology and swelling power.

Both gelatin and poly(vinyl alcohol) (PVA) can be cross linked with glutaraldehyde (GLU). In the case of gelatin, the GLU reacts with each e-NH2 functional group of adjacent lysine residues, while for PVA, the GLU reacts with two adjacent hydroxyl groups, forming acetal bridges. Thus it can be considered possible to cross link adjacent macromolecules of gelatin and PVA using GLU. In this context, the aims of this work were the development of biodegradable films based on blends of gelatin and poly(vinyl alcohol) cross linked with GLU, and the characterization of some of their main physical and functional properties. All the films were produced from film-forming solutions (FFS) containing 2 g macromolecules (PVA + gelatin)/100 g FFS, 25 g glycerol/100 g macromolecules, and 4 g GLU (25% solution)/100 g FFS. The FFS were prepared with two concentrations of PVA (20 or 50 g PVA/100 g macromolecules) and two reaction temperatures: 90 or 55 °C, applied for 30 min. The films were obtained after drying (30 °C/24 h) and conditioning at 25 °C and 58% of relative humidity for 7 days, and were then characterized. The results for the color parameters, mechanical properties, phase transitions and infrared spectra showed that some chemical modifications occurred, principally for the gelatin. However, in general, all the characteristics of the films were either typical of films based on blends of these macromolecules without cross linking, or slightly higher. A greater improvement in the properties of this material was probably not observed due to the crystallinity of the PVA, which has a melting point above 90 °C. The presence of microcrystals in the polymer chain probably reduced macromolecular mobility, hindering the reaction. Thus more research is necessary to produce biodegradable films with improved properties.