O aproveitamento de proteína de pescado como coprodutos do processo de industrialização, constitui-se em uma alternativa para a elaboração de produtos com elevada qualidade nutricional. A carne mecanicamente separada (CMS), produzida a partir de carcaças do descarte do processamento de tilápia híbrida vermelha (CMSV), Oreochromis niloticus var. Red Stirling e de tilápia preta (CMSP), Oreochromis niloticus, foram caracterizadas física, química, microbiológica e sensorialmente. Em um primeiro estudo avaliou-se a eficiência de dois tipos de equipamentos de extração mecânica da CMS, rosca- sem-fim e cinta-tambor. Posteriormente, avaliou-se a qualidade da CMS congelada durante 90 dias de armazenamento. Em seguida avaliou-se os atributos sensoriais de cor, odor e aparência da CMSV e CMSP congelada. Para a avaliação do sabor da CMS, foi adicionado ao molho de tomate com CMSV armazenada por 15 e 90 dias e a aceitação avaliada por consumidores. Foi realizado um estudo para avaliação das características de funcionalidade da CMS reestruturada da tilápia híbrida vermelha. O separador tipo rosca-sem-fim apresentou melhor rendimento de extração e controle da temperatura do processo, quando comparado ao separador do tipo cinta-tambor, embora ambos os processos tenham permitido a obtenção de CMS com teores de umidade, proteína e lipídeo adequados para o processamento de coprodutos. A avaliação da vida útil indicou que coprodutos da tilápia híbrida vermelha (CMSV) e tilápia preta (CMSP) apresentaram padrões microbiológicos, valores de pH e oxidação lipídica aceitáveis ao longo do estudo, mesmo apresentado uma descoloração ao longo do armazenamento. A avaliação sensorial para o estabelecimento da vida útil (teste de diferença do controle com provador treinado) foi realizada em períodos até 90 dias. Aos 15 dias de armazenamento, os provadores detectaram diferença significativa, porém o limite sensorial estabelecido pelos provadores (moderadamente diferente do controle) foi atingido aos 60 dias para a CMS da tilápia preta e aos 90 dias para a CMS de tilápia vermelha. A aceitação teve boa resposta, porém a intenção de compra apresentou queda de 19% para o molho adicionado de CMS estocada durante 90 dias. A CMSV é uma matéria prima, com elevado teor proteico (12%) e elevado teor lipídico (15%) e pode ser utilizada para elaboração de diferentes coprodutos. Foi possível obter produto reestruturado com boa funcionalidade tecnológica com adição de 100% de CMS de tilápia híbrida vermelha, o que demonstra a viabilidade de sua utilização, onde apresentaram respostas satisfatórias de rendimento, capacidade de retenção de água e força de penetração no reestruturado. Conclui-se que a CMS das variedades de tilápia estudadas representam um coproduto de qualidade a ser aproveitado pela indústria. Além de contribuir para para fornecer dados, junto a outros trabalhos, para se criar um padrão de identidade e qualidade da CMS de pescado, o que é de suma importância para o controle de qualidade da indústria processadora do coproduto. / The use of fish protein resulting from the industrial process constitutes an alternative to the development of co-products with nutritional quality. Mechanically recovered meat (MRM), produced from carcasses of Red hybrid tilapia, Oreochromis niloticus var. Red Stirling and black tilapia Oreochromis niloticus were characterized in terms of physical, chemical, microbiological and sensory aspects. The first study evaluated the efficiency of two mechanical extraction devices of MRM, the screw type and the belt and drum type. Later assessed the quality of frozen MRM for 90 days of storage. Then it was evaluated the sensory attributes of color, odor and appearance of defrozen MRM. The resulting MRM was used in the development of a tomato sauce and its acceptance with consumers was analyzed. A performance study of MRM restructured of red hybrid tilapia was conducted. The worm screw-type separator presented better extraction yield when compared to belt-drum type separator, but both processes allowed obtaining MRM with levels of moisture, protein and lipids suitable for processing co-products. Both MRM presented microbiological and oxidative stability after 90 days of storage. The sensory analysis of control difference for up to 90 days showed significant difference to that at 15 days of storage. The team of tasters set the value 4 (appearance, color and odor moderately different from the control) as limiting MRM shelf life to 60 days for MRM of the Nile tilapia and 90 days for MRM of the red tilapia. The tomato sauce with the addition of tilapia formulated with MRM of the red tilapia stored for 15 and 90 days was well accepted by consumers, but purchase intent dropped 19% for the product obtained from MRM with 90 days of storage. The MRM from the red hybrid tilapia is a raw material with high protein content, average 12%, and high lipid content, average 15%, and can be used to prepare different co-products of tilapia. It was possible to obtain restructured product with addition of 100% of MRM from the red hybrid tilapia with good processing characteristics, which shows viability of production with satisfactory responses of performance, water retention capacity and penetration force of restructured fish meat. We conclude that the CMS of the studied tilapia varieties represent a quality co-product to be used by the industry. Besides contributing to to provide data , along with other works , to create a standard of identity and quality of fish CMS , which is of paramount importance for the quality control of the co-product processing industry.

O caldo de cana é uma bebida saborosa, energética, não alcoólica que conserva todos os nutrientes presentes na cana-de-açúcar, muito apreciado no Brasil que, se devidamente explorado, pode alcançar um mercado consumidor com proporções ainda maiores. O presente trabalho teve como objetivos avaliar o grau de aceitação do mercado consumidor e a estabilidade do caldo de cana puro e adicionado de suco de frutas, submetido ao processamento térmico (70&#176;C/ 25 min) e/ ou à radiação gama (2,5 kGy), armazenado em garrafas de polietileno de alta densidade sob refrigeração (5 &#177; 1&#176;C). O teste de mercado do caldo de cana processado e embalado foi avaliado através da aplicação de 350 questionários em seis municípios paulistas. A qualidade do caldo de cana foi avaliada através dos parâmetros: microbiológicos (contagem de aeróbios psicrotróficos, bactérias lácticas e fungos filamentosos e leveduriformes), físico-químicos (pH, cor, acidez titulável, teor de sólidos solúveis, ratio e atividade da polifenoloxidase) e sensoriais (teste hedônico). Foi determinada a composição centesimal das bebidas elaboradas analisando-se: umidade, valor calórico, carboidratos totais, açúcares totais e redutores, extrato etéreo, proteínas, teor de ácido ascórbico, cinza e minerais. A vida útil foi determinada a cada 7 dias analisando o produto armazenado sob refrigeração durante 42 dias. Os resultados foram avaliados através de análise de variância e comparação das médias pelo teste de Tukey (p<0,05). Entre as 350 pessoas entrevistadas, mais da metade interessa-se e preocupa-se com a segurança de sua alimentação habitual e rotineira e apresenta receio em se alimentar em comércio de alimentos de rua. Os lanches foram os alimentos citados como os rotineiramente consumidos, seguidos pelo caldo de cana e pastel. Entre os entrevistados, 80% mencionaram apreciar caldo de cana, não havendo correlação entre idade e escolaridade e a preferência pela forma de consumo foi com adição de suco de limão. Cerca de 55% dos entrevistados mencionaram que consumiriam com maior freqüência o caldo de cana puro ou adicionado de suco de frutas, processado e embalado. Os processamentos aplicados ao caldo de cana não alteraram significativamente o aroma e o sabor da bebida. O teste sensorial para a escolha das melhores concentrações de suco de frutas a ser adicionado ao caldo de cana elegeu a adição de 4% de suco de limão e 10% de suco de abacaxi. A adição dos sucos de frutas ao caldo de cana nas concentrações propostas não alterou sua composição centesimal. No entanto, a adição do suco de abacaxi ao caldo de cana incrementou significativamente o teor de manganês e o de açúcares redutores quando comparado com o caldo de cana puro e adicionado de suco de limão. Considerando os resultados do teste de mercado, elegeu-se o caldo de cana adicionado de suco de limão como o preferido entre os provadores para a análise da vida útil do produto. As bebidas elaboradas pela mistura de caldo de cana e suco de limão submetidas à irradiação, pasteurização combinada com radiação e pasteurização mantiveram qualidade microbiológica, físico-química e sensorial satisfatória durante os períodos de 28, 35 e 42 dias, respectivamente, após o processamento. O tratamento térmico isolado foi considerado a melhor forma de conservação da bebida. / Sugarcane juice is a taste drink, energetic, no alcoholic that conserves all the nutrients in cane sugar. It was very appreciated by the Brazilian population and its production has been shown to be a highly lucrative business. This research had the following objectives: evaluate the acceptance of the consuming market and the stability of pure sugarcane juice or added with natural fruit juices, submitted of heat treatment (70&#176;C/ 25 min) and/ or gamma radiation (2,5 kGy) and stored in high density polyethylene bottles, under refrigeration (5 &#177; 1&#176;C). Sugarcane juice market test was evaluated through the application of 350 questionnaires on six São Paulo cities. Sugarcane juice stability was evaluated through microbiological (psicrothrophic count, lactic bacteria and yeasts and molds count), physical-chemical (pH, color, titratable acidity, soluble solids, ratio and polyphenoloxidase activity) and sensory (hedonic test) parameters. Centesimal composition was determined analyzing: humidity, caloric value, total carbohydrates, total and reducing sugars, lipids, proteins, ascorbic acid, ash and minerals. Sugarcane juice shelf life period was determinate ever 7 days over a period of 42 days stored under refrigeration. The data were submitted to the variance analysis and compared by Tukey&#39;s test (p<0,05). Among the 350 interviewed people, more of the half one is interested about its habitual food safe and care about street foods. Sandwiches had been cited foods as routinely consumed, followed for the sugarcane juice and &#34;pastel&#34;. Among the interviewed ones, 80% had mentioned to appreciate sugarcane juice. It had not correlation between age and school age and the preference for the consumption form was with lemon juice addition. About 55% of the interviewed ones had mentioned that would more frequently consume sugarcane juice processed and packed. Sugarcane juice processament didn&#39;t modify the flavor and taste of the drink. It was concluded from the sensory analyses that the best mixture was that formulated with sugarcane juice and 4% of lemon juice as well as 10% of pineapple juice. Sugarcane juice centesimal composition wasn&#39;t altered by fruit juice concentration addition. However, sugarcane juice added with 10% pineapple juice incremented manganese and reducing sugars when compared with pure sugarcane juice and added with 4% lemon juice. The market test prefered mixture was shown to be that containing sugarcane juice and natural lemon juice for evaluation the shelf life. Sugarcane juice added with 4% of lemon juice submitted to gamma radiation, heat treatment combinated with gamma radiation and heat treatment remaining satisfactory microbiological, sensory and physicalchemical characteristics until 28, 35 and 42 days respectively, after processing. These results indicated that the heat treatment was effective for sugarcane juice preservation.

Este trabalho teve como objetivo avaliar o efeito de revestimentos comestíveis na qualidade de mamão \'Formosa\' minimamente processado durante armazenamento a 5°C por 15 dias. Os tratamentos foram: o controle, e os seguintes revestimentos: amido de arroz 3%, alginato de sódio 0,5% e carboximetilcelulose 0,25%. O uso de revestimentos causou alterações nos parâmetros físicos, físico-químicos e microbiológicos do mamão minimamente processado, quando comparado ao controle. As alterações mais importantes foram: menor contagem de coliformes totais; menor respiração dos mamões tratados com amido de arroz e maior dos tratados com carboximetilcelulose, ao longo do tempo; menor descoloração da polpa dos frutos ao longo do armazenamento; maior manutenção da firmeza das amostras tratadas com carboximetilcelulose; e redução do teor de sólidos solúveis e aumento da acidez titulável. Os revestimentos não afetaram os atributos sensoriais. Como a maioria dos efeitos positivos das coberturas ocorreu no 12° e 15° dias e, considerando o custo da tecnologia relacionado ao preço dos revestimentos, a melhor opção, até 9 dias de armazenamento, consiste em fazer apenas uma boa sanitização dos frutos, como feito no controle. No entanto, se o interesse for preservar a vida útil dos mamões por um período maior, até 15 dias, os revestimentos testados podem ser utilizados com resultados satisfatórios. / This study aimed to evaluate the effect of edible coatings on the quality of minimally processed \'Formosa\' papaya during storage at 5°C for 15 days. The treatments were: the control, and the following coatings: rice starch 3%, sodium alginate 0.5% and carboxymethylcellulose 0.25%. The use of coatings caused changes in the physical, physicochemical and microbiological parameters of minimally processed papaya, when compared to control. The most important changes were: lower counts of total coliforms; lower respiration of papayas treated with rice starch and higher of those treated with carboxymethylcellulose over time; less fruit pulp discoloration during storage, increased firmness maintenance of samples treated with carboxymethylcellulose; and reduction of soluble solids and increased acidity. The coatings did not affect the sensory attributes. Since most of the positive effects of the coatings occurred at the 12th and 15th days, and considering the technology cost related to the price of coatings, the best option, until 9 days of storage, is just to do a good sanitization of fruits such as that of control samples. However, if the interest is to preserve the shelf life of papayas for a longer period, up to 15 days, the coatings tested could be used with satisfactory results.

O efeito da injeção do lactato de potássio associado ao uso de atmosfera modificada com alto oxigênio sobre músculos Longissimus lumborum de bovinos machos inteiros foi avaliado. Foram utilizados animais anelorados (com características fenotípicas de Nelore) com diferentes faixas de pH final (pHf - 48h post mortem). Foram coletados 18 músculos e divididos em 3 grupos, sendo eles: baixo (controle; 5,4 < pHf < 5,8), intermediário (5,81 < pHf < 6,3) e alto (pHf > 6,3). Na primeira etapa, foi injetada em cada músculo uma solução de lactato de potássio a 2,5%, em seguida foram cortados em bifes, embalados em atmosfera modificada contendo 80% de oxigênio e 20% de gás carbônico e estocados no escuro a 2 ± 1ºC durante 5 dias. Posteriormente, estes seguiram para um expositor refrigerado com iluminação e temperatura controlada (2 ± 1ºC), onde permaneceram por 9 dias, completando 14 dias de vida útil. Análises de composição gasosa, pH, composição centesimal, sensorial de odor, avaliação microbiológica, oxidação lipídica e cor instrumental foram realizadas nos dias: 0, 5, 8, 11 e 14. Os resultados estatísticos obtidos foram analisados pelo método de medidas repetidas no tempo e também utilizando análise não-paramétrica. A oxidação lipídica foi menor (P < 0,05) e apresentou maior estabilidade em músculos com pHf alto. Não houveram diferenças (P > 0,05) na análise sensorial de odor entre os grupos. A contagem microbiana permaneceu dentro dos limites aceitáveis para consumo humano. Os grupos de pHf intermediário e alto apresentaram uma maior (P < 0,05) estabilidade da cor (maiores valores de a*, croma e oximioglobina). Nas condições do presente estudo, a injeção do lactato de potássio associada à atmosfera com alto oxigênio atuou beneficamente na estabilidade da cor e vida útil de músculos de pHf intermediário e alto. Pode-se concluir que a injeção desta solução é uma alternativa viável para tornar a aparência de bifes provenientes de músculos L. lumborum mais atrativa para o consumidor por meio da estabilização da cor, sem prejudicar a vida útil mesmo nas condições de embalagem utilizadas. / The effect of potassium lactate enhancement in a high oxygen modified packaging on bulls\' Longissimus lumborum was studied. Zebu animals (with phenotypic characteristics of Nellore) animals with different range of ultimate pH (pHu - 48h post mortem) were used. Eighteen muscles were collected and segregated into three groups, wich were: low (control; 5.4 < pHu < 5.8), intermediate (5.81 < pHu < 6.3) and high (pHu > 6.3). In the first stage, a 2.5% potassium lactate solution was injected into each muscle, then they were cut into steaks, packaged in a modified atmosphere containing 80% oxygen and 20% carbon dioxide and stored in the dark at 2 ± 1ºC for 5 days. Later, they were displayed with light and controlled temperature (2 ± 1ºC), where remained for 9 days, completing 14 days of shelf life. Gas composition, pH, proximate analysis, odor sensory, microbiological evaluation, lipid oxidation and instrumental color analysis were performed on days: 0, 5, 8, 11 and 14. The statistical results were analyzed by the method of repeated measurements over time and also using non-parametric analysis. The lipid oxidation decreased (P < 0.05) and showed greater stability on high pHu treatment. There were no differences (P > 0.05) between the treatments on odor sensory analysis. Microbial counts remained within acceptable limits for human consumption. The intermediate and high pHu groups had a higher (P < 0.05) color stability (higher values of a*, chroma and oxymyoglobin). Under the conditions of this study, the potassium lactate enhancement associated with high oxygen atmosphere (Hi-Ox MAP) can be an alternative to increase color stability and shelf life of intermediate and high pHu muscles. It can be concluded that the injection of this solution is a viable alternative to make L. lumborum steaks appearance more attractive to the consumer through the color stabilization, without sacrificing shelf life even under packaging conditions used.

The increasing market demand for fresh produce promotes a keen interest in developing a rapid, sensitive and reliable method for monitoring plant health and determining the shelf-life of postharvest produce. The objective of this study is to explore the capability of Surface-enhanced Raman spectroscopy (SERS) in these applications. SERS integrates Raman spectroscopy which measures molecular vibrations and nanotechnology which enhances the weak Raman signals. Herein, we developed two SERS methods based on a surface detection approach using nanoparticles solution and a headspace detection approach using gold nanoparticles (AuNPs) fibers, to detect biochemical changes during postharvest storage of arugula leaves. Compared with surface detection, the headspace detection revealed significant spectral changes during the storage, particularly in the shifts around 500, 950 and 1030 cm-1. These changes analyzed using principal component analysis (PCA) to establish a prediction model for shelf-life determination. Through analyzing reference standard compounds, we identified the dimethyl disulfide (DMDS), 1-propanethiol and methanethiol (MT) were most likely to account for the signature spectra of headspace arugula at the late storage period due to the activities of spoilage bacteria. The headspace detection method was also applied to monitor the stress responses of living basil to abiotic stresses (pesticide/salinity). However, the volatile analysis of the basil plants response to abiotic stresses (pesticide/salinity) showed indistinctive results. In conclusion, the headspace detection based on SERS provides a new strategy for quality monitoring of fresh produce in the food industry.

Tesis por compendio / [EN] In the present Doctoral Thesis, antimicrobial active packaging materials, at lab and at semi-industrial scale, have been developed with the aim to reduce the natural flora of peeled and cut fruit and extend its shelf life. Packaging prototypes have been developed for their further application. Prior to developing the active materials, the most suitable active agents were selected. To that end, the antimicrobial properties of the volatile active agents citral, hexanal and linalool and mixtures thereof were evaluated against typical microorganisms related to fruit spoilage, molds and yeast, concluding that the effectiveness of the mixture is higher than the sum of the effectiveness of the individual agents. Likewise, non-volatile antimicrobial agents such as potassium sorbate and sodium benzoate were selected, which are widely used in the food industry due to their antifungal properties. With the selected active agents, monolayer polypropylene (PP) films with different concentration of the active mixture citral, hexanal and linalool, at lab scale by means of extrusion, and bilayer films at semi-industrial scale with different active layer thickness by means of coextrusion were prepared. Besides, active packaging trays were developed at semi-industrial scale by thermoforming active sheets obtained by coextrusion of PP and ethyl vinyl acetate (EVA) compounds containing potassium sorbate and sodium benzoate as active agents. Mechanical, barrier and thermal properties of the developed active packaging materials, as well as their sealability and transparency were evaluated. In general, the materials' properties were not affected in a significant manner. However, active trays decreased in transparency due to the incorporation of non-volatile active agents. The release kinetics of the volatile and non-volatile active agents were studied at different temperatures, defining their diffusion coefficients by the adjustment to mathematic models based on Second's Law Fick. Among the volatile active agents, hexanal showed a higher diffusion coefficient, followed by citral and linalool. On the other hand, very small differences were observed between potassium sorbate and sodium benzoate diffusion coefficients, being of the same order of magnitude. In vitro tests were also performed at different temperatures to evaluate the antimicrobial properties of the developed materials. In general, the active packaging materials showed high antimicrobial properties which were enhanced with the increment of temperature. Once the properties of the developed materials were evaluated, in vivo tests with peeled and cut orange and pineapple were performed by packing these fruits with the active film, active tray and their combination (active packaging system). In general, the active packaging system improved the microbiological preservation of the fruit for longer times, between 2 and 7 days for orange and pineapple, respectively, and maintained quality parameters of the fruit at stable levels for longer times. Lastly, the safety of the active packaging materials was evaluated according to the European food contact materials and food legislation, and it was concluded that these materials were not of any safety concern for the consumers. / [ES] En la presente Tesis Doctoral se han desarrollado materiales de envase activo antimicrobiano, a escala laboratorio y a escala semi-industrial, con el objetivo de reducir la proliferación de la flora natural de la fruta pelada y cortada y extender su vida útil. Se han desarrollo distintos prototipos para su posterior aplicación industrial Previo al desarrollo de los materiales de envase, se ha realizado una selección de agentes activos más idóneos. Para ello se han estudiado mediante ensayos in vitro las propiedades antimicrobianas de agentes activos volátiles, citral, hexanal y linalool y diferentes mezclas de los mismos, frente a distintos microorganismos típicos del deterioro de las frutas, mohos y levaduras, concluyendo que la efectividad de la mezcla de los tres es superior a la suma de la efectividad de los activos de forma individual. Así mismo, también se han seleccionado antimicrobianos no volátiles como el sorbato potásico y benzoato sódico, los cuáles son ampliamente empleados en la industria alimentaria debido principalmente a sus propiedades antifúngicas. Con los agentes activos seleccionados, se han desarrollado películas monocapa de polipropileno (PP) con distintas concentraciones de la mezcla activa, citral, hexanal y linalool, a escala laboratorio, mediante técnicas de extrusión, y películas bicapa a escala semi-industrial con distintos espesores de capa activa mediante coextrusión. Por otra parte, se desarrollaron bandejas activas a escala semi-industrial mediante termoconformado de láminas obtenidas por coextrusión de compuestos de PP y etilvinilaceteto (EVA) con sorbato potásico o benzoato sódico como agentes antimicrobianos. Se han evaluado las propiedades mecánicas, barrera y térmicas de los materiales activos desarrollados, así como su sellabilidad y transparencia. En general, las propiedades de los polímeros no se vieron afectadas de manera relevante. Sin embargo, las bandejas activas perdieron su carácter transparente debido a la incorporación de los agentes activos no volátiles. Se ha estudiado la cinética de liberación de los compuestos activos volátiles y no volátiles a distintas temperaturas, determinando los coeficientes de difusión de los agentes activos mediante el ajuste a modelos matemáticos de difusión basados en la Segunda Ley de Fick. Entre los agentes volátiles, el hexanal mostró un mayor coeficiente de difusión seguido de citral y linalool. Por otra parte, no hubo apenas diferencia en los coeficientes de difusión del sorbato potásico y benzoato sódico, siendo éstos del mismo orden de magnitud. Igualmente, se han realizado diferentes experimentos in vitro a distintas temperaturas para determinar las propiedades antimicrobianas de los materiales desarrollados. En general, los materiales activos presentan una elevada capacidad antimicrobiana que se ve potenciada al aumentar la temperatura de exposición. Una vez evaluadas las características de los materiales desarrollados, se han efectuado ensayos de envasado de naranja y piña pelada y cortada con las películas y las bandejas activas y con la combinación del sistema de envase bandeja activa termosellada con la película activa. En general, el sistema de envase activo mejoró la conservación de la fruta por un mayor tiempo, entre 2 y 7 días para la naranja y piña, respectivamente, presentando una gran capacidad antimicrobiana y manteniendo los parámetros de calidad de la fruta en niveles estables por un mayor tiempo. Por último, se ha estudiado la seguridad de estos materiales de acuerdo a la legislación de materiales en contacto con alimentos y la legislación alimentaria europea, concluyendo que los materiales activos desarrollados no presentan preocupación para la seguridad de los consumidores. / [CA] En la present Tesi Doctoral s'han desenvolupat materials d'envasament actiu antimicrobià, a escala de laboratori i a escala semi-industrial amb l'objectiu de reduir la proliferació de la flora natural de la fruita pelada i tallada i estendre la seua vida útil. S'han desenvolupament diferents prototips per a la seua posterior aplicació industrial. Previ al desenvolupament dels materials actius, s'han seleccionat els agents actius mes idonis estudiant mitjançant assajos in vitro les propietats antimicrobianes d'agents actius volàtils, citral, hexanal i linalool i diferents mescles dels mateixos, enfront de diferents microorganismes típics de la deterioració de les fruites -floridures i llevats- concloent que l'efectivitat de la mescla dels tres és superior a la suma de l'efectivitat dels actius de forma individual. Així mateix, s'han seleccionat antimicrobians no volàtils, sorbat potàssic i benzoat sòdic, els quals son àmpliament empleats a l'industria alimentaria per les seues propietats antifúngiques. Amb els agents actius seleccionats, s'han desenvolupat pel·lícules monocapa de polipropilè (PP) amb diferents concentracions de la mescla activa, citral, hexanal i linalool, a escala laboratori, mitjançant tècniques d'extrusió, i pel·lícules bicapa a escala semi-industrial amb diferents espessors de capa activa mitjançant coextrusió. D'altra banda, s'han desenvolupat safates actives a escala semi-industrial mitjançant termoconformació de làmines obtingudes per coextrusió de compostos de PP i etil vinil acetat (EVA) amb sorbat potàssic o benzoat sòdic com a agents antimicrobians. S'han avaluat les propietats mecàniques, barrera i tèrmiques dels materials actius desenvolupats, així com la seua sellabilidad i transparència. En general, les propietats dels polímers no es van veure afectades de manera rellevant. No obstant això, les safates actives van perdre el seu caràcter transparent a causa de la incorporació dels agents actius no volàtils. S'ha estudiat la cinètica d'alliberament dels compostos actius volàtils i no volàtils a diferents temperatures, determinant els coeficients de difusió dels agents actius mitjançant l'ajust a models matemàtics de difusió basats en la Segona Llei de Fick. Entre els agents volàtils, l' hexanal va mostrar un major coeficient de difusió seguit de citral i linalool. D'altra banda, no va haver-hi a penes diferències en els coeficients de difusió del sorbat potàssic i benzoat sòdic, sent aquests del mateix ordre de magnitud. Igualment, s'han realitzat diferents experiments in vitro a diferents temperatures per determinar les propietats antimicrobianes dels materials desenvolupats. En general, els materials actius presenten una elevada capacitat antimicrobiana que es veu potenciada en augmentar la temperatura d'exposició. Una vegada avaluades les característiques dels materials desenvolupats s'han efectuat assajos d'envasament de taronja i pinya pelada i tallada amb la safata, la pel·lícula activa i la seva combinació (sistema d'envàs actiu). En general, el sistema d'envàs actiu va millorar la conservació de la fruita per un major temps, entre 2 i 7 dies per a la taronja i pinya respectivament, presentant una gran capacitat antimicrobiana i mantenint els paràmetres de qualitat de la fruita en nivells estables per un major temps. Finalment, s'ha estudiat la seguretat d'aquests materials d'acord a la legislació de materials en contacte amb aliments i la legislació alimentària europea, concloent que els materials actius desenvolupats no presenten preocupació per a la seguretat dels consumidors. / Lara Lledó, MI. (2016). Antimicrobial packaging system for minimally processed fruit [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/61388 / TESIS / Premios Extraordinarios de tesis doctorales / Compendio

Thesis (M.Sc. Agriculture (Horticulture)) -- University of Limpopo, 2022 / The most common postharvest limitation of litchi fruit is pericarp browning, which leads to consumer rejection of the solid fruit in the market even when the edible portion is not affected. Previously, sulphur dioxide (SO2) fumigation was used to control the browning and extend shelf life of litchi fruit. However, SO2 fumigation leaves undesirable residues, alters the fruit taste and may results in health hazards for consumers. An alternative method, namely, minimal processing was used to control pericarp browning and curb postharvest losses in litchi. Litchi fruit were harvested at two maturity stages (early harvest; 120 days after full bloom (DAFB), late harvest; 130 DAFB), peeled and immersed for two (2) minutes in three (3) solutions that represented treatments, namely 1) 1% citric acid 2) 1% calcium lactate and 3) a combination of citric acid and calcium lactate both at 1% measure. The untreated arils were dipped in sodium hypochloride (NaOCl) solution for 1 minute and represented the control samples. The treated arils were packed in sterilized clamshell containers and stored at 1±0.5°C and 95% relative humidity for 12 days, then held at 10±0.5°C for 2 days for shelf life study. As a result of the interaction effect of harvest stages and postharvest pre-treatments, least mass loss percentage (1.32%), juice leakage (1.8 ml per 120 g of fruit) and pH (4.18) was observed in litchi arils harvested late and treated with 1% citric acid only under cold storage. Under shelf life study, H2 control samples presented lower mass loss (2.8%) and juice leakage (4.2 ml per 120 g of fruit). At the end of cold storage, litchi arils harvested early and treated with 1% citric acid combined with 1% calcium lactate presented better tissue strength (56.0 N) and radical scavenging activity (36.6 mmol AAE/mL), while those harvested late presented higher ascorbic acid content (72.9 µg/mL), least microbial population and total colour change (3.5). However, at the end of shelf life storage, litchi arils harvested early and treated with 1% citric acid combined with 1% calcium lactate presented lower (3.1) total change in colour. Overall, harvesting the fruit late and treating with citric acid alone or combined with calcium lactate showed the potential of maintaining better aril quality with least microbial population for up to 12 days under 1±0.5°C storage, whereas harvesteing the fruit early and treating with citric acid alone or combined with calcium lactate showed the potential of maintaining better aril quality under shelf life storage. Keywords: Litchi chinesis sonn; calcium lactate; citric acid; maturity; fresh-cut. / Agricultural Research Council (ARC), National Research Foundation (NRF) and Agri-Seta

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Thesis (M.Sc. (Horticulture)) -- University of Limpopo, 2022 / Cold storage is commonly used to prolong papaya fruit storability. Furthermore, the optimal recommended storage temperature is below 10℃ for export and distant market. However, chilling injury (CI) occurs at 10℃ or lower during prolonged cold storage. This condition hampered consumer acceptance, resulting in economic losses for producers and exporters. Therefore, the study aimed to investigate the potential of postharvest polyamine dips and storage conditions to improve the quality and shelf life of ‘Solo’ papaya fruit. The experiment was conducted as 4 x 2 factorial arranged in a completely randomised design (CRD) with eight replications. The fruits were treated with putrescine (PUT) (0 (control), 1, 2 and 3 mM) before storage for 21 days at 7.5 and 13℃ plus 5 days storage at ambient temperature. Additionally, the PUT effect on quality attributes and shelf-life were studied. The results showed that physiological and pathological disorders increased with progressive storage, irrespective of storage temperature. However, PUT treatment reduced the incidence of chilling injury and anthracnose at both 7.5 and 13℃. Additionally, the interaction of treatment and cold storage temperature significantly affected ‘Solo’ papaya fruit physical and biochemical quality attributes. Furthermore, treatment with 2 and 3 mM PUT concentration reduced changes in colour, mass, firmness, TA, and TSS compared to control. In conclusion, postharvest PUT improved ‘Solo’ papaya fruit quality and prolonged shelf-life. / AgriSETA (Agricultural Sector Training Authority)

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