Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Modified atmosphere packaging (MAP) is a dynamic process of altering gaseous composition inside a package. It relies on the interaction between the respiration rate (RR) of the produce, and the transfer of gases through the packaging material. These two processes are dependent on numerous factors such as storage temperature, film thickness and surface area, produce weight as well as free headspace within the pack. Therefore, in order to achieve the desired modified atmosphere in a given package, it is important to understand the three basic disciplines of MAP, namely produce physiology, polymer engineering, and converting technology. In this study the effects of storage conditions and duration on physiological responses i.e. respiration (RR) and transpiration rate (TR) of two pomegranate cultivars ‘Acco’ and ‘Herskawitz’, were investigated and mathematical models were developed to predict these physiological responses at given time and storage conditions. The result of this study showed that RR of whole pomegranate fruit was significantly higher than that of fresh arils, and that temperature had a significant impact on the RR of both whole fruit and fresh arils. The influence of time, and the interaction between temperature and time also had significant influences on RR of fresh pomegranate arils. These findings highlight the significance of maintaining optimal cold-storage condition for packaged arils or whole fruit along the supply chain. In addition, mathematical models based on the Arrhenius-type equation and the power function equation coupled with Arrhenius-type equation accurately predicted the effect of temperature and the influence of time and temperature on the RR of fresh pomegranate arils for both cultivars. Furthermore, the results of experimental and model prediction studies showed that both relative humidity (RH) and storage temperature had significant effects on TR. RH was the variable with the greatest influence on TR, and it was observed that arils were best kept at 5°C and 96% RH to maintain quality for 8 days. The applicability of the transpiration model developed was validated based on prediction of TR of pomegranate arils under different combinations of storage conditions. The model adequately predicted TR and provides a useful tool towards understanding the rate of water loss in fresh pomegranate arils as affected by storage conditions and duration. The effect of passive-MAP engineering design parameters as a function of produce weight contained, storage temperature and duration on fresh pomegranate arils was investigated. The result showed that produce weight of aril content, temperature and the interaction between temperature and time had slight but insignificant effects on measured physicochemical quality attributes. However, headspace gas concentration was significantly influenced by produce weight and storage temperature. Oxygen (O2) composition decline below 2% after day 3 and 5 at 15 and 10 ºC, respectively, while samples at 5 °C did not reach below 2% throughout the study. On the other hand, CO2 levels increased significantly during storage for all packaging conditions. This study showed the importance of a systematic approach to the design of optimal MAP systems. At lowest storage temperature the inability to achieve desired modified atmosphere (MA) required for optimal storage of arils despite the increase in produce weight, suggests that the use of active gas modification (gas flushing with recommended atmosphere) would be necessary. However, the present results show that at higher temperature macro/micro perforations would be required on the polymeric films used in the present study in order to avoid critical levels of O2 and CO2. The influence of passive MAP, storage temperature and duration on volatile composition and evolution of packaged pomegranate arils was investigated. The results showed that changes in aroma compounds were dependent on cultivar differences, storage condition and duration. Using GC-MS analysis of pomegranate juice HS-SPME extracts, a total of 18 and 17 volatiles were detected for ‘Herskerwitz’ and ‘Acco’, respectively. Furthermore, flavour life (7 days) was shorter than the postharvest life (10 days) for both cultivars. There was a decrease in volatile composition during the storage period (aldehydes < alcohols < esters) while the concentration (%) and composition of ethyl esters increased with storage time. These results highlight the need for a more precise definition of flavour shelf life for MApackaged pomegranate arils and other packaged fresh produce. The importance of maintaining optimal cold storage condition, selection of appropriate packaging materials and a systematic approach to the design and application of MAP systems has also been shown. / AFRIKAANSE OPSOMMING: Gemodifiseerde atmosfeer-verpakking (GAV) is ’n dinamiese proses waartydens die gassamestelling binne-in ’n verpakking gewysig word. Dit berus op die wisselwerking tussen die respirasietempo (RT) van die produkte en die oordrag van gasse deur die verpakkingsmateriaal. Hierdie twee prosesse is van verskeie faktore soos bergingstemperatuur, dikte van die film en oppervlakte, gewig van die produkte asook vry boruimte binne-in die pakkie afhanklik. Om dus die gewenste gemodifiseerde atmosfeer in ’n gegewe verpakking te verkry, is dit belangrik om die drie fundamentele dissiplines van GAV te begryp, naamlik produkfisiologie, polimeerontwerp, en omsettingstegnologie. In hierdie studie is die gevolge van bergingstoestande en -duur op fisiologiese reaksie, met ander woorde, respirasie- (RT) en transpirasietempo (TT) van twee geselekteerde granaatkultivars ‘Acco’ en ‘Herskawitz’, ondersoek en wiskundige modelle is ontwikkel om ons in staat te stel om hierdie fisiologiese reaksies by gegewe tyd- en bergingstoestande te voorspel. Die resultaat van hierdie studie het aangetoon dat die respirasietempo (RT) van heel granaatvrugte aansienlik hoër was as die RT van vars arils, en temperatuur het beduidende uitwerking op RT van beide heel vrugte en vars arils gehad. Die invloed van tyd, en die wisselwerking tussen temperatuur en tyd het ook ’n beduidende invloed op die RT van vars granaatarils gehad. Hierdie bevinding beklemtoon die belang van die handhawing van optimale koelbewaringstoestande vir verpakte arils of heel vrugte met die aanvoerketting langs. Daarbenewens wiskundige modelle wat gebaseer op die Arrhenius-tipe vergelyking en die magsfunksie-vergelyking gepaard met Arrhenius-tipe vergelyking, die uitwerking van temperatuur en die invloed van tyd en temperatuur op die RT van vars granaatarils vir beide kultivars onderskeidelik voldoende en akkuraat voorspel. Afgesien die resultate van eksperimentele en modelvoorspellings die studies aangetoon dat beide relatiewe humiditeit (RH) en bergingstemperatuur ’n beduidende uitwerking op TT het. RH was die veranderlike met die grootste invloed op TT, en it was waargeneem dat dit die beste was om arils teen 5°C en 96% RH te bewaar (8 dae). Die toepaslikheid van die transpirasiemodel wat ontwikkel is, is bevestig op grond van voorspelling van TT van granaatarils onder verskillende kombinasies van bergingstoestande. Die model het TT voldoende voorspel en sou ’n bruikbare instrument wees ten einde die waterverliestempo in vars granaatarils en ander vars produkte, soos deur bergingstoestande en duur beïnvloed, te begryp. Die uitwerking van passiewe-GAV ontwerpparameters as ’n funksie van gewig van die produkte, bergingstemperatuur en duur op vars granaatarils is ondersoek. Dit het aan die lig gebring dat gewig van die produkte, temperatuur en die wisselwerking tussen temperatuur en tyd ’n geringe maar onbeduidende uitwerking op gemete fisikochemiese gehalteeienskappe gehad het. Die gaskonsentrasie in die boruimte is betekenisvol beïnvloed deur gewig van die produkte en bergingstemperatuur. Die O2-samestelling het tot benede 2% gedaal na 3 en 5 dae by 15 en 10 ºC, onderskeidelik, terwyl monsters by 5 °C deur die studie heen nooit laer as 2% was nie. Aan die ander kant, CO2-vlakke het gedurende berging betekenisvol verhoog wat betref alle verpakkingstoestande. Hierdie studie het die belangrikheid van ’n sistematiese benadering by die ontwerp van ’n optimale GAV-stelsel aangetoon. By die laagste bergingstemperatuur dui die onvermoë om die gewenste gemodifiseerde atmosfeer (GA) wat vir optimale berging van arils benodig word, te verkry – ondanks die toename in die gewig van die produkte – daarop dat die gebruik van aktiewe gasmodifisering (gasspoeling met aanbevole atmosfeer) nodig sou wees. Egter die huidige uitslae aangetoon dat by hoër temperatuur, sou makro/mikroperforasies op die polimeerfilms wat gebruik word in die onderhawige studie egter nodig wees ten einde kritiese vlakke van O2 en CO2 te verhoed. Die invloed van passiewe GAV, bergingstemperatuur en duur op onstabiele samestelling en evolusie van verpakte granaatarils is ondersoek. Die resultate aangetoon dat veranderinge in aromaverbindings afhanklik was van kultivarverskille, bergingstoestande en duur. Met behulp van GC-MS-analise van granaatsap HS-SPME-ekstrakte, het ons ’n totaal van 18 en 17 vlugtige stowwe vir ‘Herskawitz’ en ‘Acco’, onderskeidelik bespeur. Verder het ons waargeneem dat die smaakleeftyd (7 dae) korter was as die na-oesleeftyd (10 dae) vir beide kultivar. Daar was ’n afname in vlugtige samestelling (aldehiede < alkohole < esters) terwyl die konsentrasie (%) en samestelling van etielesters het met bergingstyd verhoog. Hierdie resultate het die aandag gevestig op die behoefte aan ’n meer presiese definisie van geur-raklewe vir GA-verpakte granaatarils en ander verpakte vars produkte. Die belang van die handhawing van die optimale koelbewaringstoestand, seleksie van geskikte verpakkingsmateriaal en ’n sistematiese benadering tot die ontwerp van ’n optimale GAVstelsel, is ook beskryf.

Atualmente, existem inúmeros questionamentos quanto aos prováveis efeitos mutagênicos e carcinogênicos dos antioxidantes sintéticos no organismo, e devido a isto, hoje em dia estudos tendem a promover a substituição destes compostos por naturais com o intuito de maior segurança do alimento, sendo que estes apresentam benefícios potenciais à saúde. O objetivo deste estudo foi o uso de antioxidantes naturais obtidos de ervas e especiarias no desenvolvimento de produtos cárneos a base de carne ovina buscando suas propriedades antioxidantes e sensoriais, bem como agregar valor ao produto final, desenvolvido com carne de baixo valor comercial. O apelo de saudabilidade dos produtos foi obtido pela adição de extratos antioxidantes naturais à base de ervas aromáticas selecionadas em função de seu poder antioxidante e harmonização de sabores com a carne ovina. Um primeiro experimento (Capítulo 2) consistiu na avaliação da capacidade antioxidante dos extratos de 13 espécies vegetais, sendo selecionados por Cluster analysis em relação a três métodos colorimétricos e sensorialmente após a adição em produto cárneo. O extrato selecionado foi avaliado quanto a acidez, à identificação e quantificação de compostos fenólicos e utilizado para a elaboração de hambúrguer congelado (Capítulo 3) e linguiça cozida (Capítulo 4), em diferentes concentrações, além de hambúrguer refrigerado sob atmosfera modificada (80% O2 + 20% CO2) (Capítulo 5), sendo comparados com tratamentos sem antioxidante (controle) e contendo antioxidante sintético (eritorbato de sódio ou BHT). Estes produtos cárneos foram avaliados durante armazenamento, respectivamente de 120, 135 e 20 dias, a partir de análises físico-químicas, sensoriais e microbiológicas, sendo inicialmente caracterizados quanto à composição centesimal. Orégano, manjerona, melissa e alecrim foram os extratos selecionados após agrupamento por similaridade quanto à capacidade antioxidante, sendo que os hambúrgueres elaborados com estes quatro extratos naturais não comprometeram a aceitação sensorial em relação ao eritorbato de sódio (P>0,05). Resumidamente, os produtos cárneos elaborados mostraram resultados relevantes quanto à estabilidade oxidativa, apresentando os tratamentos contendo extrato natural, efeitos antioxidantes melhores e/ou compatíveis aos antioxidantes sintéticos. Hambúrguer congelado apresentou mais de 50% de redução (P<0,001) para nível de substâncias reativas ao ácido tiobarbitúrico (TBARS), enquanto que linguiças cozidas apresentaram os menores valores para compostos voláteis (P<0,001) aos 135 dias de estocagem e a presença do extrato em hambúrgueres sob atmosfera modificada (ATM) manteve a qualidade sensorial por até 15 dias de armazenamento. Apesar de diferentes sistemas testados, o ensaio de redução férrica (FRAP) foi o método em comum mais eficaz para estimar a quantidade adequada de antioxidante natural a ser adicionada em comparação ao eritorbato de sódio. Em conclusão, extrato de orégano adicionado em produtos a base de carne ovina apresentou efeitos antioxidantes equivalentes aos antioxidantes sintéticos, não comprometendo a maioria dos parâmetros físico-químicos, microbiológicos e sensoriais, sendo considerado uma alternativa viável e favorecida pela grande vantagem da saudabilidade. / Currently, there are many questions concerning probable mutagenic and carcinogenic effects of synthetic antioxidants in the organism, and because of this, nowadays studies tend to promote the substitution of these by natural compounds with the aim of greater food safety and potential benefits for the health. The objective of this study was the use of natural antioxidants obtained from herbs and spices in the development of meat products ovine meat looking theirs antioxidant and sensory properties as well as add value to the final product, which was developed with low commercial value meat. The healthiness appeal of the product was obtained by adding natural antioxidants based extracts of aromatic herbs to be selected according to its antioxidant power and harmonization of flavors with the sheep meat. A first experiment (Chapter 2) was performed to evaluate the antioxidant capacity of 13 plant species extracts, being selected by Cluster analysis in relation to three colorimetric methods and sensory, after the addition in meat product. The selected extract was evaluated for acidity, identification and quantification of phenolic compounds and used for the preparation of frozen hamburger (Chapter 3) and cooked sausage (Chapter 4), at different concentrations, and refrigerated hamburger under modified atmosphere (80% O2 + 20% CO2) (Chapter 5), being compared to treatments without antioxidant (control) and containing synthetic antioxidant (sodium erythorbate or BHT). These meat products were evaluated during storage, respectively of 120, 135 and 20 days, from physical-chemical, sensory and microbiological analyzes, being initially characterized for chemical composition. Oregano, marjoram, lemon balm and rosemary were the extracts selected after grouping by similarity of the antioxidant capacity, and the hamburgers made with these four natural extracts did not affect the sensory acceptance in comparison to sodium erythorbate (P>0.05). Briefly, the meat products showed significant results in terms of oxidative stability, being the treatments containing natural extract presented best effects antioxidant and/or compatible to synthetic compounds. Frozen burger presented more than 50% reduction (P<0.001) for tiobarbituric acid reactive substance TBARS, while cooked sausages had the lowest values for volatile compounds (P<0.001) at 135 days of storage, and the extract presence in burgers under modified atmosphere kept the quality sensory up to 15 days. Although different systems tested, ferric reducing antioxidant power (FRAP) was more effective common method to estimate the appropriate amount of natural antioxidant to be used in comparison to sodium erythorbate. In conclusion, oregano extract added products in the sheep meat presented equivalent antioxidant effects without to compromise the majority of physical-chemical, microbiological and sensory parameters, being thus considered a viable alternative, favored by the great advantage of healthiness.

O pedúnculo de caju é um pseudofruto carnoso, suculento, de ótimo aroma, apresenta altos teores de ácido ascórbico e compostos fenólicos. Apesar da condição nutricional, a vida útil e a comercialização in natura do pedúnculo é limitada principalmente devido a sua alta perecibilidade e susceptibilidade ao ataque de microrganismos patogênicos. O objetivo do trabalho foi estudar métodos de conservação pós-colheita de pedúnculos de caju, entre eles: radiação gama, quitosana e atmosfera modificada passiva, de forma primeiramente individual para avaliar o efeito na conservação dos principais atributos físico-químicos, nutricionais e nos aspectos fisiológicos e depois em combinação para verificar efeitos sobre a vida útil, na atividade antioxidante e no perfil de compostos voláteis. No experimento de irradiação a dose de 2,0 kGy reduziu drasticamente a incidência de podridão mas ocasionou alta perdas de firmeza, ácido ascórbico, fenólicos e de pigmentos. A dose de 0,5 kGy proporcionou a melhor qualidade dos pedúnculos, pois além de reduzir podridões, reduziu perda de massa, manteve valores adequados de firmeza e, diferente da maior dose, não interferiu na pigmentação da epiderme, além de manter altos os níveis de compostos fenólicos e reduzir a adstringência. Com relação ao uso de quitosana, as concentrações de 1 e 2% foram eficientes na conservação dos atributos de qualidade de pedúnculos de caju, sendo que a concentração de 2% foi mais eficiente na redução de podridões, além de reduzir a adstringência do pedúnculo. O uso da atmosfera modificada, por meio do filme de PEBD, que proporcinou atmosfera de 11% de O2 e 8% de CO2, foi a mais eficiente na conservação dos atributos da qualidade visual e nutricional de pedúnculos de caju até o 20º dia após a colheita. Mudanças mais dráticas da atmosfera, como observadas em PP e BOPP não causaram anaerobiose, porém, a maior barreira aos gases e ao vapor de água, levou a perda de alguns atributos de qualidade. Os tratamentos de combinação de irradiação+quitosana e irradiação+atmosfera modificada foram eficientes na conservação dos pedúnculos de caju por estender a vida útil até o 25º dia após a colheita, reduzindo a incidência de podridão e perda de massa e mantendo adequada a firmeza da polpa, fato não alcançado com os tratamentos individuais. Além disso, a combinação irradiação + quitosana manteve também altos níveis de atividade antioxidante e perfil de voláteis característico de um pedúnculo agradável, sendo desta forma a combinação mais indicada. A irradiação e a quitosana quando utilizadas como tratamentos individuais também preservam a qualidade volátil, porém até o 20º dia após a colheita. / Cashew apple is a fleshy, juicy pseudofruit of great aroma, presents high levels of ascorbic acid and phenolic compounds. Despite the nutritional condition, the shelf life and in natura commercialization of the peduncle is limited mainly due to its high perishability and susceptibility to the attack of pathogenic microorganisms. The objective of this research was to study post-harvest methods of cashew peduncles among them: gamma radiation, chitosan and passive modified atmosphere, in a first individual way to evaluate the effect on the conservation of the main physical-chemical, nutritional and physiological aspects and then in combination to check effects on shelf life, antioxidant activity and the volatile compound profile. In the irradiation experiment the dose of 2.0 kGy drastically reduced the incidence of rot but caused high losses of firmness, ascorbic acid, phenolics and pigments. The dose of 0.5 kGy provided the best quality of the peduncles, because besides reducing rot, reduced mass loss, maintained adequate values of firmness and, unlike the higher dose, did not interfere in the pigmentation of the epidermis, besides maintaining high levels of phenolic compounds and reduce astringency. Regarding the use of chitosan, the concentrations of 1 and 2% were efficient in the conservation of the attributes of cashew peduncles, being that the concentration of 2% was more efficient in the reduction of rot, besides reducing the astringency of the peduncle. The use of the modified atmosphere through the LDPE film, which provided an atmosphere of 11% O2 and 8% CO2, was the most efficient in preserving the visual and nutritional quality attributes of cashew peduncles until the 20th day after harvest. More dramatic changes of the atmosphere, as observed in PP and BOPP did not cause anaerobiosis, however, the greater barrier to gases and water vapor, led to the loss of some quality attributes. The treatments of irradiation+chitosan and irradiation+modified atmosphere treatments were efficient in the conservation of the cashew peduncles by extending the shelf life until the 25th day after harvesting, reducing the incidence of rot and loss of mass and maintaining the firmness of the pulp. A fact not reached with individual treatments. In addition, the combination of irradiation+chitosan also maintained high levels of antioxidant activity and volatile profile characteristic of a pleasant peduncle, thus being the most indicated combination. Irradiation and chitosan when used as individual treatments also preserve the volatile quality, but until the 20th day after harvest.

This study compared the effect of packaging method (0.4% carbon monoxide, 80% oxygen or vacuum), storage time (7, 14 and 21 days) and internal cooking temperature 49, 57, 66, 71 and 79°C) on color and thiobarbituric acid (TBA) values of top sirloin steaks and ground beef patties. Ground beef was obtained from 3 different sources (chuck, loin and trim). All samples were stored at 2°C for 7, 14 and 21 days. All raw ground beef samples stored in 0.4% carbon monoxide remained bright red throughout the 21-day storage period. The phenomenon of premature browning (appearance of cooked color at lower than normal cooking temperatures) was observed in samples stored in high oxygen. TBA values were highest for the samples stored in 80% oxygen. Internal a* redness values were lowest for samples stored in 80% oxygen. Percent myogobin denaturation (PMD) increased with increase in internal cooking temperature and was highest for the ground beef samples stored in 80% oxygen. The a* redness values were highest for raw steaks stored in 0.4% CO. Steaks stored in vacuum had a uniform purple color, but some browning was noticed on the surface of the samples by day 14. PMD and TBA values of cooked top sirloin steaks were highest for the samples stored in 80% oxygen This study confirms that high oxygen packaging promotes rancidity in ground beef and top sirloin steaks. Packaging in 0.4% carbon monoxide helps maintain a bright cherry red color in ground beef and top sirloin steaks for up to 21 days.

Fresh produce is increasingly implicated in outbreaks of foodborne illness. Internalization of bacterial pathogens into produce is of particular concern as internalized pathogens are unlikely to be removed by surface sanitizers. It is therefore necessary to develop treatments that will reduce their prevalence and numbers on fresh produce. Irradiation is a penetrating nonthermal treatment that effectively eliminates bacteria. Irradiated baby spinach leaves up to 1.0 kGy showed negligible (P>0.05) changes in color, texture, vitamin C, total carotenoids, and chlorophyll content compared to non-irradiated controls throughout storage (15 days at 4oC). This research also shows that irradiation effectively reduces viable Escherichia coli cells internalized in lettuce, and that decontamination is not influenced (P>0.05) by lettuce variety. Irradiation effectively reduced the population of internalized pathogens in a dose-dependent manner (3-4 log reduction at 1.0 kGy). Microscopy images suggest that the contamination sites of pathogens in leafy vegetables are mainly localized on crevices and in the stomata. A careful design of the treatment (understanding dose distribution) will effectively eliminate pathogens while maintaining produce quality. The use of modified atmosphere packaging increased (P<0.05) the sensitivity of pathogens (Salmonella spp. and Listeria spp.) to irradiation in baby spinach leaves (up to 25%). Increasing concentration of oxygen increased (P<0.05) sensitivity of both microorganisms. Radiosensitization could be affected (P<0.05) by production of ozone, which increases with increasing dose-rate and oxygen concentration, and reducing temperatures. Antimicrobial effectiveness of various active compounds was determined against Salmonella spp. and Listeria spp. Inclusion complexes were prepared with antimicrobial compounds and -cyclodextrin. The effectiveness of the microencapsulated compounds was tested by spraying them on the surface of baby spinach leaves inoculated with Salmonella spp. The increase in radiosensitivity (up to 40%) varied with the antimicrobial compound. Spherical poly (DL-lactide-co-glycolide) (PLGA) nanoparticles with entrapped eugenol and trans-cinnamaldehyde were synthesized for future antimicrobial delivery applications. All loaded nanoparticles proved to be efficient in inhibiting growth of Salmonella spp. and Listeria spp. The entrapment efficiency for eugenol and trans-cinnamaldehyde was 98% and 92%, respectively. Controlled release experiments (in vitro at 37oC for 72 hrs) showed an initial burst followed by a slower release rate of the antimicrobial entrapped inside the PLGA matrix.

Meat is one of the most important food products. European Union countries, including Lithuania, are the main meat producers in the world - their production comprises more than 16 % of processed meat. In the world commerce meat products conclude 12,8 % of market place, of which 39 % - pork. The purpose of the work - to analyse the preservative gas impact on freshness sustention of pork products. The main tasks are to review the freshness rates of pork products, their evaluation methods; to discuss the ways of long-lasting freshness sustention, which are usable in the processed food industry; to analyse the preservative gas method on the freshness sustention of meat products; to research and to compare the microbiological pollution of the sausages, packed in the preservative gas and not packed in it. The methods of research are: analysis of the primary documents; analysis of the secondary documents; analysis of the scientific literature; analysis of the statistics, microbiological research of pork sausages. The most effect of the preservative gas usable for the packing meat products is obtained by packing smoked sausages, which microbiological pollution after 20 days, increases 1,2 – 2 times.

This study explored the in vitro and in situ antilisterial inhibitory activity of 16 essential oils during indirect exposure: Spanish Basil oil (Ocimum basilicum), Bay oil (Pimenta racemosa), Italian Bergamot oil (Citrus bergamia), Roman Chamomile oil (Anthemis nobilis), Sir Lanka Cinnamon oil (Cinnamomum zeylanicum), Citral, Clove Bud oil (Syzygium aromaticum), Cumin Seed oil (cuminum cyminum), Eucalyptus oil (Eucalyptus globulus), Eugenol, Geranium extract (Pelargonium graveolens), Marjoram oil (Origanum majorana), Neroli extract (Citrus aurantium), Peppermint oil (Mentha piperita L.), Rosemary oil (Rosmarinus officinalis L.),and Spanish Sage oil (Salvia officinalis L.). All essential oils were tested against Listeria monocytogenes (ATCC 4644). In vitro inhibitory activity was determined using the microatmosphere method at three temperatures (37°C, 24°C, 4°C) and six possible volumes (0, 10µl, 25µl, 50µl, 100µl, 150µl, or 200µl). In situ inhibitory activity was determined using inoculated bologna slices packaged in Modified Atmosphere Packaging (80% O2, 20% CO2). Essential oils (0, 0.13ml, 1.35ml, or 2.70ml) were injected into the sample packages adjacent, but not touching, the bologna slices and stored at 24°C for 24h. Basil oil displayed the least antilisterial activity across the three temperature applications in vitro. Peppermint, Cumin Seed, and Citral consistently exhibited the greatest antilisterial activity among the temperature applications in vitro. However, only Eugenol applied at 1.35ml achieved a mean one log10 CFU/ml reduction in LM in situ, which could not be replicated. Peppermint (P < 0.048) displayed significant differences between application volumes (0.13ml, 1.35ml) but did not attain a mean one log10 CFU/ml reduction in LM. This study suggests that while various essential oils can display antilisterial activity in vitro, transitioning into a MAP food system warrants further research in mode of actions and application volumes.

Microbiological quality of food is important both because of hygiene and health and has a significant influence on the shelf life of foods. The aim of this thesis was to evaluate samples of meat products for contamination by microorganisms. There was soft meat product, the product heat-processed and heat-treated. Evaluated how they affect the product and then cutting up into the vacuum packaging the total number of microorganisms, the influence of ambient temperature on the development of bacteria and the production have been using the new technology will benefit the health quality of the product. As revealed from the results, a product bar showed fewer organisms than product, which was sliced and then packaged in a vacuum. The fault was apparently slicing equipment that was not completely disinfected, and there was a transfer of bacteria. Therefore, it is necessary to improve sanitation and to see to their strict compliance. Resulting in the effect of temperature on the growth of microorganisms. The rising temperature is increased, the number of microorganisms. Use of air-conditioned chambers in the production of meat products is shown in terms of reducing the total number of microorganisms as a positive.

FONTENELE, Maria Alves. Conservação pós-colheita do bacuri sob condições ambiente e refrigeração associada à atmosfera modificada. 2007. 138 f. : Dissertação (mestrado) - Universidade Federal do Ceará,Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2007, / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:32:55Z No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-17T15:33:10Z (GMT) No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) / Made available in DSpace on 2016-06-17T15:33:10Z (GMT). No. of bitstreams: 1 2007_dis_mafontenele.pdf: 762859 bytes, checksum: 9b4ae0982f4245ee130a56173754c103 (MD5) Previous issue date: 2007 / This work had for objectives to verify through the characterization of fruits of the bacuri tree of the Area of the North Middle, which the best atmosphere conditions, of times and storage temperatures, to prolong the life post-harvest of the bacuri (Platonia insignis Mart) for commercialization in natura. The fruits picked in the plant, stored under modified atmosphere they presented great appearance it expresses and it interns until the end of the experiment (25 days), while stored them under atmosphere it adapts they had your appearance it expresses committed after the sixth day, however your internal appearance was satisfactory until the end of experiment. A mass loss it was larger in the fruits without film, with losses of up to 47% to the 25 days of storage, against 8% in the fruits with film. The physical-chemical quality of the pulp was little affected during the storage with prominence for the total soluble solids that presented smaller percentile in the fruits with film. The fruits picked in the plant, stored 7 ºC in modified atmosphere they had your appearance it expresses committed after 20 days, for offenses for the cold, while in the temperatures of 9 and 11 ºC useful life was of 36 days. The coloration of the fruits just developed of clear green for yellow in the temperatures of 9 and 11 ºC, and to 11 ºC the coloration reached a larger intensity. The quality of the pulp practically was not affected by the storage temperatures. The fruits been hit after you/they fall of the plant, stored the temperature it adapts and modified atmosphere had your appearance it expresses committed in the nineteenth day of storage and the intern after 21 days, already for the fruits stored under refrigeration and modified atmosphere, the appearance expresses it was committed to the 28 days of storage, in spite of presenting satisfactory internal appearance until the thirtieth fifth day. The mass loss was of 7.74% and 2.17%, in the fruits stored 25 ºC and 12 ºC, respectively. The fruits storage the temperature adapts they had revenue around 16%, while, that the fruits stored under refrigeration the revenue it was of 15%. The values of SST decreased during the storage in the two appraised temperatures. After 35 days of storage to 25 ºC the fruits presented 12.12 ºBrix on average, while to 12 ºC after 42 days of storage presented a value of 11.28 ºBrix. The values of the pH presented little variation through the time in the two storage conditions and the AT obtained larger variation in the storage to 25 ºC. The relationship SST/AT presented considerable variations among I begin him/it and the end in the two storage types, being more intense in the storage the temperature adapts. The fruits presented low tenors of phenolic compounds in all the fractions characterizing the bacuri pulp as little astringent, demonstrating potential so much for consumption in natura, besides little vitamin tenor C, in the two storage conditions. / Este trabalho teve por objetivos verificar através da caracterização de frutos do bacurizeiro da Região do Meio Norte, quais as melhores condições de atmosfera, de tempos e temperaturas de armazenamento, para prolongar a vida pós - colheita do bacuri (Platonia insignis Mart) para comercialização in natura. Os frutos colhidos na planta, armazenados sob atmosfera modificada apresentaram ótima aparência externa e interna até o final do experimento (25 dias), enquanto que os armazenados sob atmosfera ambiente tiveram sua aparência externa comprometida após o sexto dia, entretanto sua aparência interna foi satisfatória até o final do experimento. A perda de massa foi maior nos frutos sem filme, com perdas de até 47% aos 25 dias de armazenamento, contra 8% nos frutos com filme. A qualidade físico-quimica da polpa foi pouco afetada durante o armazenamento com destaque para os sólidos solúveis totais que apresentaram menor percentual nos frutos com filme. Os frutos colhidos na planta, armazenados a 7 ºC em atmosfera modificada tiveram sua aparência externa comprometida após 20 dias, por injúrias pelo frio, enquanto que nas temperaturas de 9 e 11 ºC a vida útil foi de 36 dias. A coloração das frutas evoluiu de verde claro para amarelo apenas nas temperaturas de 9 e 11 ºC, sendo que a 11 ºC a coloração atingiu uma maior intensidade. A qualidade da polpa praticamente não foi afetada pelas temperaturas de armazenamento. Os frutos apanhados após caírem da planta, armazenados a temperatura ambiente e atmosfera modificada tiveram sua aparência externa comprometida no décimo nono dia de armazenamento e a interna após 21 dias. Já para os frutos armazenados sob refrigeração e atmosfera modificada, a aparência externa foi comprometida aos 28 dias de armazenamento, apesar de apresentar aparência interna satisfatória até o trigésimo quinto dia. A perda de massa foi de 7,74% e 2,17%, nos frutos armazenados a 25 ºC e 12 ºC, respectivamente. Os frutos armazenamento a temperatura ambiente tiveram rendimento em torno de 16%, enquanto, que os frutos armazenados sob refrigeração o rendimento foi de 15%. Os valores dos SST decresceram durante o armazenamento nas duas temperaturas avaliadas. Após 35 dias de armazenamento a 25 ºC os frutos apresentaram em média 12,12 ºBrix, enquanto que a 12 ºC após 42 dias de armazenamento apresentaram um valor de 11,28 ºBrix. Os valores de pH apresentaram pouca variação através do tempo nas duas condições de armazenamento e a AT obteve maior variação no armazenamento a 25 ºC. A relação SST/AT apresentou variações consideráveis entre o inicio e o final nos dois tipos de armazenamento, sendo mais intenso no armazenamento a temperatura ambiente. Os frutos apresentaram baixos teores de compostos fenólicos em todas as frações caracterizando a polpa de bacuri como pouco adstringente, demonstrando potencial para consumo in natura, além de pouco teor de vitamina C, nas duas condições de armazenamento.

Made available in DSpace on 2014-06-11T19:33:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-05-13Bitstream added on 2014-06-13T19:23:55Z : No. of bitstreams: 1 martins_rn_dr_jabo.pdf: 2474760 bytes, checksum: e83a101de743b7d10a0c8a6df9d9eb8f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Este trabalho teve como objetivo avaliar o estádio de maturação, tipos de embalagens, uso de aditivos naturais e temperaturas de armazenamento de pêssegos „Aurora-1‟ minimamente processados visando sua qualidade e manutenção da vida de prateleira. Os frutos foram adquiridos em pomar comercial localizado no município de Taiúva-SP nos meses de outubro e novembro de 2007 e 2008. O trabalho foi dividido em cinco experimentos: no primeiro foram estudados estádios de maturação “de vez” e “maduro”. No segundo testou-se o efeito da aplicação de ácido ascórbico ou cloreto de cálcio. No terceiro verificou-se o efeito de embalagens como atmosfera modificada passiva. No quarto, foi verificado o efeito de temperaturas de refrigeração e tipos de cortes. No quinto testou-se o efeito da aplicação de ácido ascórbico, l-cisteína, ácido ascórbico e cloreto de cálcio, ácido cítrico e isoascorbato de sódio na prevenção do escurecimento enzimático. As análises de aparência, massa fresca, firmeza, coloração, composição gasosa, sólidos solúveis, acidez titulável, razão sólidos/acidez, pH, açúcares solúveis e redutores, pectina total e solúvel, solubilização, ácido ascórbico, atividade das enzimas peroxidase e polifenoloxidase foram efetuadas a cada três dias para os experimentos 1, 2, 3 e 5 e, a cada quatro dias para o quarto experimento. Frutos no estádio de maturação “de vez” levaram a produtos com melhor aparência e maiores teores de açúcares e de ácido ascórbico. Produtos tratados com ácido ascórbico a 2% apresentaram melhor aparência, maior conteúdo de açúcares e de ácido ascórbico, manutenção da cor e menor atividade enzimática. O filme de PVC 14 μm proporcionou boa conservação da aparência e prevenção do escurecimento dos produtos. A interação do armazenamento a 3 ºC e corte do fruto em oito fatias proporcionaram... / This study aimed to evaluate the maturation stage, packaging types, natural additives use and storage temperatures of minimally processed „Aurora-1‟ peaches in order to maintain their quality and shelf life. The fruits were purchased from a commercial orchard in the area of Taiúva-SP in October and November, 2007 and 2008. The work was divided in five experiments: in the first one, maturated green and maturated stages were studied. In the second one, it was tested the effect of ascorbic acid or calcium chloride application. In the third one, it was observed the packaging effect as passive modified atmosphere. In the fourth one, it was showed the effect of cooling temperatures and cutting types. In the fifth one, it was tested the effect of ascorbic acid, l-cysteine, ascorbic acid and calcium chloride, citric acid and sodium isoascorbate to prevent enzymatic browning. Analyses of appearance, fresh weight, firmness, color, gas composition, soluble solids, acidity, ratio, pH, soluble and reducing sugars, total and soluble pectin, solubilization, ascorbic acid, peroxidase and polyphenoloxidase activity were done each three days for the first, second, third and fifth experiments, and each four days for the fourth one. Matured green fruits led to products with better appearance and higher levels of sugars and ascorbic acid. Products treated with 2% ascorbic acid showed a better appearance, higher content of sugars and ascorbic acid, color maintenance, and lower enzymatic activity. 14μm PVC film use showed good appearance preservation and browning prevention of the products. Interaction between storage at 3°C and fruit cutting into eight slices provided the best product appearance, with a higher content of soluble solids. 1% Cysteine gave non-characteristic product odor, which limited its use. Minimally processed 'Aurora-1' peaches can be sold for up to nine days, when matured... (Complete abstract click electronic access below)