Tecnología emergente: Campo de pulsos eléctricos (PEF) para el tratamiento de alimentos y su efecto en el contenido de antioxidantes

RESUMEN Los métodos de conservación de alimentos no-térmicos han generado un considerable interés en la industria alimentaria como potencial alternativo a los métodos tradicionales de procesamiento. Uno de los métodos no-térmicos más estudiados es el de campos eléctricos pulsados o PEF (Pulsed Electric Fields). La aplicación de PEF en el procesamiento de alimentos permite limitar la exposición a altas temperaturas y reducir la necesidad de aditivos alimentarios. En PEF, se expone al alimento a pulsos eléctricos generando poros en la membrana celular, este fenómeno se le conoce como electroporación. La electroporación promueve la inactivación de organismos patógenos, reduce la actividad enzimática, favorece la transferencia de masa, mantención de color, sabor y contenido de compuestos antioxidantes, mejora la eficiencia en el procesamiento de alimentos y mantiene de cualidades organolépticas que son atractivas tanto para el consumidor como también para la industria. Los antioxidantes son sustancias capaces de proteger a las células de los radicales libres. La acción de los antioxidantes es de interés tanto del punto de vista sanitario, como industrial. Existe abundante evidencia que asocia el consumo de antioxidantes como factor protector ante enfermedades. Por otro lado, los antioxidantes cumplen un rol importante en la duración de los alimentos ya que actúan como conservantes, prolongando su vida útil. La utilización de PEF, respecto a otras tecnologías para el procesamiento de alimentos, ha demostrado un aumento en la extracción, menor pérdida por temperatura y una mayor disponibilidad de compuestos de interés, incluidos antioxidantes.

ABSTRACT Non-thermal food preservation methods have gained considerable interest in the food industry as a potential alternative to traditional processing methods. One of the most studied non-thermal methods is Pulsed Electric Fields (PEF). The application of PEF in food processing allows limiting exposure to high temperatures and reducing the need for food additives. In PEF, food is exposed to electrical pulses generating pores in the cell membrane, this phenomenon is known as electroporation. Electroporation promotes the inactivation of pathogenic organisms, reduces enzyme activity, favors mass transfer, maintains color, flavor and antioxidant compound content, improves food processing efficiency and maintains organoleptic qualities that are attractive to both the consumer and the industry. Antioxidants are substances capable of protecting cells from free radicals. The action of antioxidants is of interest both from a health and industrial point of view. There is abundant evidence that associates the consumption of antioxidants as a protective factor against diseases. On the other hand, antioxidants play an important role in the shelf life of foods as they act as preservatives, prolonging their shelf life. The use of PEF, compared to other food processing technologies, has shown an increase in extraction, lower temperature loss and greater availability of compounds of interest, including antioxidants.

Comparative Evaluation of Antioxidant Potential in Thermally Processed, Underutilized Food Grains of the Himalayan Region

Aims: To determine the bioactive components and total antioxidant capacity (TAC) in selected underutilized crops of the Himalayan region viz. Barnyard millet, Grain amaranth, Rice bean, Black soybean and Horsegram. Study Design: Experimental design (Lab experiment). Place and Duration of Study: Department of Foods and Nutrition, College of Home Science, G. B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, in the year 2016-18. Methodology: We applied different processing techniques (covered pan cooking and pressure cooking) in the underutilized crops and analyzed the total phenol, total flavonoids and total antioxidant capacity (Ferric reducing antioxidant power (FRAP) assay and (2, 2-Diphenyl-1-picrylhydrazyl) (DPPH) by using standard methods. Results: It was found that black soybean had highest phenolic content after both thermal treatments (3233.76 mg GAE/100 g for pan cooked and 1883.11 mg GAE/100 g for pressure cooked samples) and TAC by both FRAP (6423.76 mg TE/100 g for pan-cooked and 4415.58 mg TE/100 g for pressure cooked) and DPPH (536.41 and 453.98 mg TE/100g for pan and pressure cooked samples, respectively) method. Among raw samples, rice bean contained the highest flavonoid content and TAC by FRAP assay. In contrast, raw grain Amaranth showed the lowest phenolic content. Further, pressure cooking was found to be better for barnyard millet, while in pulses, pan cooking yielded the best results (in terms of increased value/lower losses). Conclusion: It can be concluded that among pulses pan cooked black soybean was found to have a good store of bioactive compounds as compared to rice bean and horse gram. The pressure cooking method was found to be suitable for millet like a barnyard.

Pelleting of diet for weaning pigs of different initial weights / Peletização da dieta para leitões recém-desmamados com diferentes pesos iniciais

ABSTRACT: Physical form effect of the pre-starter diet supplied during the post-weaning period from 21 to 41 days of age on diet digestibility and animal performance in terms of zootechnical performances of light-weight (5.82kg) and heavy-weight weaning piglets (6.32kg) was evaluated, as well as the residual effects of the treatments until slaughter. Forty-eight female pigs at 21 days of age were evaluated. The experimental design was completely randomized in a 2x2 factorial scheme (meal/pelleted diet vs. light-weight/heavy-weight piglets), with six replicates for the nursery phase and 12 replicates for the growing-finishing phases. Animals received the experimental diet from 21 to 41 days of age. Data were analyzed with ANOVA, setting the significance in 5%. Feeding with the pelleted diet resulted in a 39% greater daily weight gain and a 28% greater feed conversion rate for piglets from weaning to 40 days of age. Pelleting also resulted in a decrease in feed wastage during the first week after weaning (9.15% for meal diet vs. 1.68% for pelleted diet) and; consequently, the results showed an increase in feed consumption. Digestible energy of the pelleted diet (3,626kcal kg-1) was greater than that of the meal diet (3,424kcal kg-1). The physical form improved the performance of weaning pigs and the digestibility of the pre-starter diet, but there wasn't residual effect of the physical form and the weight of a piglet at weaning on live weight at slaughter.

RESUMO: Avaliou-se o impacto da forma física da dieta pré-inicial em leitões leves (5,82kg) e pesados (6,32kg) no período pós-desmame sobre o desempenho zootécnico e digestibilidade da dieta, bem como o efeito residual dos tratamentos até o abate. Foram utilizados 48 leitões fêmeas com 21 dias de idade, distribuídos em delineamento inteiramente ao acaso, em esquema fatorial 2x2 (farelada/peletizada vs. leitões leves/pesados), com seis repetições na fase de creche e 12 repetições na fase de crescimento e terminação. Os leitões receberam as dietas experimentais dos 21 aos 40 dias de idade. Os dados foram submetidos à análise de variância ao nível de 5% de probabilidade. Observou-se que a peletização melhorou em 39% o ganho de peso diário e 28% a conversão alimentar do desmame aos 40 dias de idade. Ao considerar a redução de desperdício da ração peletizada (9,15 vs. 1,68%) na primeira semana pós-desmame, a peletização da dieta proporcionou aumento do consumo de ração. Ao avaliar a digestibilidade da dieta, observou-se que a energia digestível aumentou de 3.424kcal kg-1 na forma farelada para 3.626kcal kg-1 na forma peletizada. A forma física da dieta proporcionou efeitos positivos sobre o peso vivo dos leitões desmamados e energia digestível da dieta. Porém, não foi observado efeito residual da forma física ou peso ao desmame sobre o peso vivo ao abate.

Farelo de arroz integral processado por infravermelho em diferentes períodos de tempo na dieta de frangos de corte / Full fat rice bran processed by infrared in different time periods in broiler diets

Trata-se de um estudo de metabolizabilidade em frangos de corte Cobb, para testar os benefícios do processamento térmico por infravermelho no farelo de arroz integral (FAI) em diferentes tempos (0, 6, 8 e 10min). O experimento foi realizado através do método de substituição, em que 20% de uma dieta referência (DR) a base de milho e farelo de soja foi substituída pelos FAIs processados em diferentes tempos. Usou-se um delineamento experimental completamente casualizado com 5 tratamentos e 10 repetições de uma ave. Entre 21 e 28 dias de idade das aves, foi feita a coleta total de excretas, com 4 dias de adaptação às dietas e 3 de coleta. A dieta com FAI 6min teve melhor aproveitamento em relação às demais e foi a única que não piorou os coeficientes de metabolizabilidade em relação à DR. Na comparação da metabolizabilidade dos ingredientes isolados, não houve diferenças estatísticas. Porém, conforme aumentou o tempo de processamento, diminuiu a solubilidade e a metabolizabilidade da proteína. O processamento térmico por infravermelho não foi capaz de melhorar a metabolizabilidade do FAI para frangos de corte.

This is a study of metabolizability in broilers Cobb, to test rice bran infrared (RB) thermal processed at different times (0, 6, 8 and 10min). It was used a reference diet (RD) based on corn and soybean in which 20% of RB was included. The experiment design was completely randomized, with 5 treatments and 10 replicates. Each replicate was a 21 day old bird. After 4 days of diet adaptation, total excreta was collected, during 3 subsequent days. Diet with RB processed at 6 was better used than the others, the only one that did not differ from RD. Comparing RB processing times, there were no significant difference between them, regarding digestibility. Processing time was negatively related to protein solubility and protein metabolizability. Infrared heat processing was not able to improve FAI metabolizability for broilers.

Stability of carotenoids, phenolic compounds, ascorbic acid and antioxidant capacity of tomatoes during thermal processing / Estabilidad de carotenoides, compuestos fenólicos, ácido ascórbico y capacidad antioxidante de los tomates durante el tratamiento térmico

In the present investigation we ascertained the stability of lycopene, ß-carotene, ascorbic acid, polyphenolic compounds and total antioxidant capacity (AC) during the process of concentrating tomatoes into two tomato pastes (10 and 15ºBrix). Thermal processing increased the content of lycopene, total phenolic compounds, total flavonoids, and the individual phenolic compounds quercetin, rutin, chlorogenic and cafeic acids, whereas it decreased the other analysed compounds. However, lycopene in the 15ºBrix-tomato paste decreased due to the extension of thermal processing, which led to degradation. The AC of aqueous and organic extracts was measured and different AC values were observed depending on the antioxidant profile of the extract and assay used (TEAC and FRAP). AC expressed in dry matter decreased as result of ascorbic acid losses. Overall, thermal processing enhanced the nutritional value of tomatoes, mainly by increasing the lycopene and phenolic antioxidants, but the extension of treatment must be controlled to prevent lycopene degradation.

En el presente trabajo hemos estudiado la estabilidad del licopeno, ß-caroteno, ácido ascórbico, compuestos fenólicos y capacidad antioxidante total (AC) durante el procesado de concentración del tomate en dos pastas de tomate (10 y 15ºBrix). El tratamiento térmico incrementó el contenido de licopeno, compuestos fenólicos totales, flavonoides totales y el contenido de quercetina, rutina y ácido clorogénico y cafeíco, disminuyendo el contenido de los otros compuestos analizados. Sin embargo, el contenido de licopeno en la pasta de tomate de 15ºBrix disminuyó debido al tratamiento térmico como consecuencia de la degradación térmica. La AC de los extractos acuosos y orgánicos de las muestras proporcionaron diferentes resultados dependiendo del perfil de antioxidante extraído y del método de análisis utilizado (TEAC y FRAP). La AC expresada en material seca disminuyó como resultado de las pérdidas de ácido ascórbico. En general el procesado térmico incrementa el valor nutricional del tomate , debido principalmente al incrmento de licopeno y compuestos fenólicos, pero la extensión del tratamiento en tiempo y temperatura debe ser controlado para prevenir la degradación del licopeno.

Effect of heat treatment of digestion-resistant fraction from soybean on retarding of bile acid transport in vitro

In this study, we investigated the heat effect of digestion-resistant fraction (RF) from soybean on retarding bile acid transport in vitro. The RFs from soybean retarded bile acid transport. A raw, unheated RF of soybean (RRF-SOY) was significantly more effective than the heated RF of soybean (HRF-SOY). The RS1 which physically trapped in milled grains and inaccessible to digestive enzyme after 18 hrs incubation level of content in RRF-SOY was found to be as high as 24.1% and after heating the RS1 of HRF-SOY was significantly reduced to 16.8%. The X-ray diffraction pattern of RF from soybean was altered after heat treatment. The RFs from soybean were characterized by peak at diffraction angles of 12.0degrees and 20.0degrees corresponding to RS content. Cellulose contents of RRF-SOY was 5% higher than that of HRF-SOY and pentosan contents of RRF-SOY was 5% higher than that of HRF-SOY, too. Whereas the hemicellulose content of RRF-SOY was 13% lower than HRF-SOY.

Causas dos defeitos em conservas enlatadas de sardinhas colhidas no comércio varejista de Niterói/Brasil / Causes of spoilage in canned of sardines collected from retail trade in Niterói -Brazil

Foram examinadas 600 latas de sardinhas no comércio varejista de Niterói e Rio de Janeiro. Nestas, observou-se que 20 (3.33%) apresentavam defeitos de recravação, tais como: vêes, bicos e franjas, sendo que 45% estavam amassadas e 76% estufadas. Na análise microbiológica foi constatado, em 19 latas cultura mista de microrganismos à microscopia de imersão. Na análise dos recipientes, estas mesmas latas apresentaram vazamentos através de furos ou defeitos de recravação. A causa mais provável da deterioração do conteúdo destas latas é a contaminação pós-processamento.

Six llundred cans of sardines collected from local stores in Niterói -Brazil, 20 cans (3.33%) had major container defects. Leaking seams at the manufacturer's end and droops and vees on the canner's end, presented swelled and crushed. Nineteen cans of sardines were submited to a. microbiological analysis and showed a mixed culture of microrganisms when observed under immersion. In the containers analysis, these same cans presented holes or cracks in their double seams, permitting fluid to leak in or out. The probable cause of the spoilage material presents inside the cans must be the post-processing contamination.