Comparison of energy consumption, color, ascorbic acid and carotenoid degradation in guava (Psidium guajava) pulp during conventional and ohmic heating.

This study aimed to compare the effect of ohmic and conventional heat treatments on red guava pulp, evaluating the effects on pulp color, degradation kinetics of ascorbic acid and carotenoids, together with the thermal efficiency of both treatments. Samples were heated by conventional heating (water bath) and ohmic heating (platinum electrodes) using alternating voltage of 21.2 V/m and average frequency of 60 Hz at temperatures of 60, 70 and 80 °C for 110 min. In general, the ascorbic acid degradation followed a first order kinetics, for both heat treatments, the pulp color showed no significant variation (p < 0.05) according to the type and time of heating applied, whereas the carotenoid content was favored by ohmic heating, at the two lowest temperatures tested. As for the heat transfer process, the ohmic treatment showed an average thermal efficiency of 40.93%, while the conventional heating, 2.62%, proving to be a promising emerging technology for processing viscous foods with suspended particles like fruit pulps.

Film production with flaxseed mucilage and polyvinyl alcohol mixtures and evaluation of their properties.

Flaxseed mucilage was extracted with distilled water, dried and used for film production with polyvinyl alcohol (PVA) (ratio 1:1) of different hydrolysis degrees (88.0 and 98.3%). The properties of the films were evaluated by determining the thickness, tensile measurements, moisture content, water vapor permeability, apparent opacity, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) analysis and thermogravimetric analysis. Flaxseed mucilage, when mixed with PVA, produces less resistant, less rigid, more-flexible films, has a higher thermal stability, and does not change the water vapor barrier properties compared with pure mucilage films. SEM revealed that films with mucilage and PVA mixtures formed a compact and homogeneous structure, corroborating the FTIR spectra that indicated a chemical interaction between these two biopolymers. In general, the degree of PVA hydrolysis did not influence the properties of the films when mixed with flaxseed mucilage extract. Therefore, films obtained from mixtures of flaxseed mucilage and PVA can be an interesting and advantageous alternative for producing bio-based packaging.

Starch-PVA based films with Clitoria ternatea flower extract: Characterization, phenolic compounds release and compostability.

The kinetic release of phenolic compounds from biodegradable films with Clitoria ternatea flower extract (ECT) in different food-simulant fluids and compostability were evaluated for the first time. This work aimed to incorporate ECT in starch-PVA-based film formulations, and the antioxidant capacity, total phenolic compounds, opacity, color, mechanical properties, compostability, and polyphenol release in different fluid simulants were determined. The results obtained showed that antioxidant activity and the total phenolic compounds were ECT dose dependent. Due to its antioxidant properties, ECT interfered with the film's composting process, reaching an average weight loss of 70 %. Additionally, the addition of ECT interfered with the mechanical properties, reducing the tensile strength, probably due to the plasticizer effect. The type of simulating fluid influenced the release of polyphenols from the films, and the presence of water favored the release because it hydrated and swelled the starch-PVA matrix, facilitating diffusion. The classic zero- and first-order models were the most effective in describing the release kinetics of polyphenols from the films. The results of this study demonstrate that the antioxidant potential and the release of polyphenols from starch-PVA-based films in different simulated fluids allow their application in active packaging, making them a sustainable alternative for food preservation.

Inulin as prebiotic encapsulating agent for the production of spray-dried Hibiscus sabdariffa L. tea microcapsules.

Due to the high content of phenolics and anthocyanins of Hibiscus sabdariffa L. tea and the sensibility of these bioactive compounds, this work aimed to optimize the obtention of microcapsules by spray-drying, using inulin as a carrier agent. Using a Box-Behnken Design, the effects of inlet temperature (130, 150, and 170 °C), feed flow rate (5, 10, and 15 mL min-1), and inulin concentration (5, 10, and 15 g L-1) were evaluated. It was possible to obtain pale-rose, slightly sweet instant powders with good total polyphenol content (1.12 mgGAE g-1) and anthocyanins encapsulation efficiency (32.3-60.6%), besides moisture (4.61-17.79%) and water activity (0.221-0.501), indicating physico-chemical and microbiological stability of the microcapsules. A simultaneous optimization with the desirability function was performed to maximize all the response variables analyzed, and the optimum conditions of 5 g L-1 of inulin, inlet temperature of 170 °C, and feed flow rate of 83 mL min-1 were found.

Edible coatings and films with incorporation of prebiotics -A review.

Prebiotics are compounds naturally present in some foods or can be synthesized by microorganisms and enzymes. Among the benefits associated with prebiotic consumption are the modulation of the intestinal microbiota that increase the production of short chain fatty acids and prevent the development of some disorders such as colon cancer, irritable bowel syndrome, diabetes, obesity, among others. Traditionally, prebiotics have been used in diverse food formulations to enhance their healthy potential or to improve their technological and sensory properties. However, different alternatives for the production of prebiotic products are being explored, such as edible coatings and films. Therefore, this review aims to highlight recent research on edible coatings and films incorporated with different prebiotics, the concept of prebiotics, the general characteristics of these materials, and the main production methods, as well as presenting the perspectives of uses in the food industry. Current works describe that polyols and oligosaccharides are the most employed prebiotics, and depending on their structure and concentration, they can also act as film plasticizer or reinforcement agent. The use of prebiotic in the coating can also improve probiotic bacteria survival making it possible to obtain fruits and vegetables with synbiotic properties. The most common method of production is casting, suggesting that other technologies such as extrusion can be explored aiming industrial scale. The use of film and coating carried of prebiotic is an emerging technology and there are still several possibilities for study to enable its use in the food industry. This review will be useful to detect the current situation, identify problems, verify new features, future trends and support new investigations and investments.

Analytical validation of an ultraviolet-visible procedure for determining vitamin D3 in vitamin D3-loaded microparticles and toxigenetic studies for incorporation into food.

Vitamin D is a water-insoluble compound presented in two main forms (D2 and D3), susceptible to environmental conditions. Microencapsulation is an alternative to supplements and preserve vitamin D properties in foods. Entrapment efficiency (EE) is the main property to evaluate the encapsulation effectiveness and therefore it is of interest the study of analytical methods for the identification and quantification of this compound within the particle. This paper describes a low cost UV-Vis methodology validation to the identification and quantification of vitamin D3 in microparticles produced by hot homogenization. The method was validated following the International Conference on Harmonization (ICH) guidelines. To guarantee safe application in foodstuff, microparticles toxigenicity was evaluated with Allium cepa L. in vivo model, showing no cytotoxic nor genotoxic potential. High entrapment efficiency was obtained, the results also demonstrated that the concentration of vitamin D3 in microparticles can be safely accessed by the validated method.

Araucaria angustifolia (Bertol.) Kuntze extract as a source of phenolic compounds in TPS/PBAT active films.

There is growing interest in the development of biodegradable packaging materials containing natural antioxidant extracts. In this sense, the use of extracts obtained from agro-industrial byproducts has proved to be a sustainable alternative. In this study, Pinhão extract, a byproduct of Pinhão (Araucaria angustifolia (Bertol.) Kuntze) seed consumption, was characterized by HPLC-DAD-ESI/MSn, demonstrating the presence of eight phenolic compounds, (+)-catechin and (-)-epicatechin being the most abundant molecules. TPS/PBAT films containing Pinhão extract were produced by blown extrusion and their properties (tensile properties, thermal characteristics and microstructure) were evaluated in order to determine the effect of the presence of extracts. Results suggested that the interaction between the phenolic compounds of the extract and the polymeric matrix caused the reduction in the crystallinity degree, and an increase in the starch glass transition temperature. The presence of Araucaria angustifolia (Bertol.) Kuntze extract significantly (p < 0.05) affected the color and opacity of the film. Regarding water vapor permeation, no significant difference (p > 0.05) was detected. However, the water solubility and the contact angle with water (polar solvent) and diiodomethane (non-polar solvent) significantly changed due to the extract addition. Moreover, the Pinhão extract conferred significant antioxidant capacity to the TPS/PBAT films as determined by DPPH, suggesting that this material can be applied as an active packaging material.

Caracterização de filme à base de amido de residuo de aveia com composto antifúngico natural / Characterization of edible film based on starch from industrial oat residue added with natural antifungal compound

Tendo em vista o estudo para o melhor aproveitamento do resíduo de aveia industrial, o trabalho teve como objetivo desenvolver e caracterizar um filme à base de amido de resíduo industrial de aveia, com composto antifúngico natural, visando analisar a aplicabilidade em frutos pós-colheita na forma de revestimento comestível. O extrato bruto (EB) contendo composto antifúngico foi produzido a partir do cultivo de Hansenula wingei em Caldo Meio Para Levedura sem agitação (25ºC/96 horas). O filme foi desenvolvido pelo método casting, empregando o EB como substituinte integral da água, o amido e o glicerol e as seguintes propriedades foram determinadas: espessura, solubilidade, permeabilidade ao vapor d’água e perfuração. As propriedades do filme foram satisfatórias para aplicação como revestimento em frutos in natura.

Thermoplastic starch/polyester films: effects of extrusion process and poly (lactic acid) addition.

Biodegradable films were produced using the blown extrusion method from blends that contained cassava thermoplastic starch (TPS), poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with two different extrusion processes. The choice of extrusion process did not have a significant effect on the mechanical properties, water vapor permeability (WVP) or viscoelasticity of the films, but the addition of PLA decreased the elongation, blow-up ratio (BUR) and opacity and increased the elastic modulus, tensile strength and viscoelastic parameters of the films. The films with 20% PLA exhibited a lower WVP due to the hydrophobic nature of this polymer. Morphological analyses revealed the incompatibility between the polymers used.

Production and characterization of alginate microparticles obtained by ionic gelation and electrostatic adsorption of concentrated soy protein / Produção e caracterização de micropartículas de alginato obtidas por gelificação iônica e adsorção eletrostática de concentrado proteico de soja

ABSTRACT: Microencapsulation is used for protection and release of bioactive compounds. Combination of encapsulation methods allows the production of matrices with better technological properties compared to the application of one of the methods alone. Use of ionic gelation produces porous microparticles, and coating it with a protein, by electrostatic interaction, may contribute to a better protection of the active compound. The objective of the research was to produce alginate microparticles (AG) through ionic gelation and to coat them with soluble protein from soy protein concentrate. Two factors were studied, calcium concentration during ionic gelation (0.8, 1.6 and 2.4% w/w) and pH (3.5 and 7.0) of the protein solution for electrostatic interaction. Zeta potential (ZP) of biopolymers and microparticles were determined. Microparticles were characterized according to its morphology, average size and size distribution, as well as protein adsorption. Microparticles presented (154-334μm) multinuclear distribution of active compound, continuous and smooth surface, with a great standard deviation considering average size. The calcium concentration did not influence the protein adsorption on microparticles.The pH used in protein adsorption showed significant effect, with higher adsorption occurring at pH 3.5 (6.5 to 6.7% w/w, dry basis,db, of adsorbed protein) compared to pH 7.0 (<2.0% w/w, db, of adsorbed protein) indicating that electrostatic interaction was determinant for the protein coating. At this situation, ionic gelation microparticles and proteins presented ZP with opposite charges (pH>pKa AG<Isoelectric point, IP).

RESUMO: A microencapsulação é utilizada para a proteção de compostos bioativos e controle de sua liberação. A combinação de métodos de encapsulação permite a obtenção de matrizes com melhores propriedades tecnológicas em relação às técnicas utilizadas individualmente. Na gelificação iônica são produzidas micropartículas porosas, e o recobrimento por interação eletrostática com uma proteína permite a obtenção de micropartículas mais protetivas. O objetivo do trabalho foi produzir micropartículas de alginato (AG) através da gelificação iônica e recobri-las com proteínas solúveis de concentrado proteico de soja. Dois fatores foram estudados, o teor de cálcio utilizado na gelificação iônica (0,8,1,6 e 2,4% m/m) e o pH (3,5 e 7,0) para o recobrimento eletrostático com uma camada proteica. Os potenciais zeta (PZ) dos biopolímeros e das micropartículas foram determinados. As micropartículas foram caracterizadas quanto a morfologia, tamanho médio e sua distribuição e quanto ao teor de proteína adsorvida nas situações estudadas. As micropartículas obtidas apresentaram-se (154-334μm) com recheio distribuído de forma multinuclear, com superfície continua e visualmente lisas, porém com variação grande no tamanho médio. A variação do teor de cálcio não foi significativa na adsorção proteica. O pH utilizado na adsorção proteica foi significativo, com adsorções muito maiores em pH 3,5 (6,5 - 6,7% m/m de proteína adsorvida, base seca) comparado ao pH 7,0 (<2,0% m/m de adsorção proteica, base seca), indicando que a interação eletrostática foi determinante no recobrimento proteico. Nesta situação, micropartículas AG e a proteína apresentam PZ com cargas opostas (pH>pKa AG<ponto isoeletrico, PI).