Marcos David Ferreira

Strawberry fruit resistance to simulated handling

ABSTRACT: Harvest operations are currently the main source of mechanical injury of strawberry( Fragaria x ananassa Duch. ). Experiments were designed to simulate conditions encountered duringcommercial handling. Individual fruits were subjected to impact or compression forces with similarenergy to determine the sensitivity to mechanical injury. Bruise volume was used as the measurementof injury. Bruise severity increased as a function of impact energy for both impact types. However,dropped fruits had larger bruise volume than fruits submitted to pendulum impactor at the sameenergy level. Doubling the impact energy (0.040 to 0.083 J) increased bruise volume by 7 times (13 to91 mm 3 ). Fruits dropped from 380 mm (0.075 J) showed 71% greater bruise volume than those droppedfrom either 130 mm (0.025 J) or 200 mm (0.040 J). Compressed fruits showed higher bruise volume thanother tests. Some cultivars are more susceptible to compression forces than others. ‘Sweet Charlie’berries showed bruise volume 40% higher than the others cultivars when subjected to compression.Fruits subjected to impact showed bruise volume lower than the compressed fruits, indicating thepossibility to be handled and graded in a packing line.Key words:

Modified Atmosphere Packaging for Perishable Plant Products

Packaging perishable plant products is one of the more important steps in the long and complicated journey from grower to consumer. Millions of different types of packages are used for produce around the world and the number continues to increase as the industry introduces new packaging materials and concepts. Packing and packaging materials contribute a significant cost to the produce industry; therefore it is important that packers, shippers, buyers, and consumers have a clear understanding of the wide range of packaging options available (Boyette et al., 1996). This fact chapter describes some of the many types of packaging materials, including their functions, uses, and limitations. Within packaging plastics for plant products, if commodity and film permeability characteristics are properly matched, an appropriate atmosphere can evolve passively through consumption of O2 and production of CO2 during respiration (Mir & Beaudry, 2002). Gas exchange and respiration rate through the package material are the processes involved in creating a modified atmosphere inside a package that will extend shelf life of fresh fruits and vegetables. The major methods for measuring respiration rates, along with their advantages and limitations are discussed. Modified atmosphere technologies have great potential in a wide range of applications in plant products. The usual methods of respiration rate determination can be the static system, the flowing system and the permeable system (Fonseca et al., 2002). The respiration rate of fresh produce can be expressed as O2 consumption rate and/or CO2 production rate. Factors affecting the respiration rate and respiratory quotient are outlined, stressing the importance of temperature, O2 and CO2 concentrations, and storage time (Kader et al., 1989). Modified atmosphere packaging should always be considered as a supplement to proper temperature and relative humidity management. The differences between beneficial and harmful concentrations of oxygen and carbon dioxide for each kind of produce are relatively small, so great care must be taken when using these technologies. Temperature has been identified as the most important external factor influencing respiration (Tano et al., 2007). The internal factors affecting respiration are the type and maturity stage of the commodity. Vegetables include a great diversity of plant organs such as fruits, roots, tubers, seeds, bulbs, sprouts, leaves and stems that have different metabolic activities and consequently different respiration rates. Different varieties of the same product exhibit specific respiration rates. The success of modified atmosphere packaging greatly depends on the accuracy of the predictive respiration rate (Kader, 2002). The main objective of this chapter is to present different packaging materials using modified atmosphere for perishable plant products, focusing

Effects of antibrowning solution and chitosan-based edible coating on the quality of fresh-cut apple

Fresh-cut apples were treated with an antibrowning solution and with a chitosan-based edible coating associated to antibrowning agents and the effects on the deterioration at low temperature were studied. The combined effect of ascorbic acid (AA), citric acid (CA) and chitosan was also evaluated. Control, coated and uncoated apples were packed in polyethylene terephthalate trays and the changes in headspace atmosphere, colour, firmness and microbial growth measured along ten days of storage at 5°C. The samples coated with 1% AA + 2% CA + chitosan maintained a good colouration until day 6, similar to those treated with 1% AA + 2% CA without chitosan. Afterwards, the fruits became darker and similar to the control. A slight reduction in the rates of CO2 production was observed in all samples. Ethylene increased continuously during storage although gas production was extremely low. Texture did not change for all treatments; showing values around 9.0 to 10.0 N. Growth of Salmonella, and total and fecal coliforms were not detected. The chitosan coating treatment was the most effective in inhibiting growth of moulds and yeasts, with count of 1.7 CFU g–1. Chitosan coating could be an alternative for preserving quality of fresh-cut ‘Gala’ apples. Results from this study suggest that.

Qualidade do tomate de mesa em diferentes etapas, da fase de pós-colheita

Manual classification using wooden boxes (K) are still very common in Brazil. The main goal of this work was to characterize tomatoes of the cultivar Debora type, for maturity index, diameter and external defects at harvest time and at Retail Market, CEASA, Campinas, Sao Paulo State, Brazil. This research also evaluated parameters related to mechanical injury (%), weight loss (%) and quality during the main phases (1) harvest; (2) before field sorting and classification; (3) after field sorting and packaging in K boxes; (4) at CEASA. 120 fruits were taken at each stage. Defects and physical damage were evaluated using a score scale. Fruits sampled in the field showed external damages, due to bruising from bamboo stakes, insects attack and physiological and nutritional disorders. Fruits were harvested mainly at green maturity stage (48%). But, when sampled at CEASA this amount dropped to 26,3%, having mixed diameters fruits, 55,4% at 50-60mm and 43,9% over 60 mm. The results showed an increase in mechanical injury (%), weight loss (%) and loss of quality during the stages. Fruits taken directly from field showed better quality (45%) after storage for 21 days than fruits sampled at terminal market, CEASA (5,8%).

Onion bulb quality due to pre-harvest treatments.

Pre-harvest treatments were evaluated to enhance onion bulb quality in different onion cultivars adapted to tropical conditions. Parameters used were weight loss, skin color and thickness, bulb and firmness. Trials were carried out in 1997. Four treatments were used: control, copper oxicloride (250 g 100 L-1); boric acid (250 g 100 L-1), and a combination of the two chemical treatments (250 g 100 L-1 of each). Treatments were applied at bulbing stage. The six cultivars were Serrana, Regia, Crioula, and the hybrids HT, HS-1 and HS-2. Bulbs were stored at room temperature prior to evaluations. Results showed that copper oxicloride (250 g 100 L-1) induced an increase in skin thickness, decreased weight loss and enhanced color in cultivars. Dark skin cultivars had a better response to pre-harvest treatments in relation to light skin cultivars. Firmness was not affected by pre-harvest treatments.

Nanoscaled Platforms Based on SiO2 and Al2O3 Impregnated with Potassium Permanganate Use Color Changes to Indicate Ethylene Removal

The development of novel tools/devices to monitor and oxidize ethylene (C2H4), a volatile compound responsible for the ripening and senescence in plants, can be a potential approach to maintain and provide information on the postharvest quality of fruits and vegetables. Here, we propose nanoscaled platforms based on silica (SiO2) and alumina (Al2O3) nanoparticles impregnated with potassium permanganate (KMnO4) that use color changes to indicate ethylene removal. SiO2 and Al2O3 in the microscale and nanoscale were impregnated with varied concentrations of KMnO4 through a simple mixture route, which systems were capable of oxidizing the ethylene in a closed atmosphere under relative humidity of 45, 60, 75, and 90%. Ethylene removal and color changes were monitored using gas chromatography and colorimetry, respectively. The nanoscaled platforms impregnated with KMnO4 were capable of scavenging ethylene more efficiently for 1-h exposure. Additionally, the color changes experienced by the nanoscaled platforms, arising from the chemical reduction of potassium permanganate, function as an indicator of ethylene removal, which is particularly suitable for postharvest application.

An electronic tongue based on conducting electrospun nanofibers for detecting tetracycline in milk samples

The development of novel and portable chemical sensors aimed at the food industry is of prime importance for food safety issues, and nanomaterial science can greatly contribute to this task. In this context, a careful choice of the sensing material is essential for achieving high performance sensor arrays, such as those employed in nanostructured electronic tongues (e-tongues). In the current work, an impedimetric e-tongue based on gold interdigitated microelectrodes (IDEs) modified with polyamide 6/polyaniline (PA6/PANI) electrospun nanofibers was developed, characterized and used to detect tetracycline (TC) residue in fat and skimmed milk samples. By analyzing the electrical resistance data collected by the e-tongue, which were treated by Principal Component Analysis (PCA), the e-tongue was able to identify the presence of TC residues (from 1 to 300 ppb) in fat and skimmed milk samples. The results obtained demonstrate the ability of the approach of modifying IDEs with conducting electrospun nanofibers to be used as sensing units in the e-tongue, aiming to analyze complex matrices such as milk without any prior pre-treatment.

Evaluation of hydration indexes in kale leaves

Hydration indexes are practical variables for quantifying plant water stress and can be useful for agronomic purposes. Three adapted hydration indexes based on relative water content, volumetric hydration, and leaf turgor pressure were evaluated in kale (Brassica oleracea var. acephala) leaf segments. Relative water content and volumetric hydration were measured in leaf segments after a water infiltration procedure with the aim of filling its large intercellular volumes (@18%v/v). The infiltration was done using a hydrostatic weighing procedure and with the aid of vacuum to fully hydrate the leaf segments. These two relative indexes were proportional to the transpiration-induced leaf water loss. The third index, turgor pressure, was measured with a Wiltmeter® instrument. Similarly, the turgor pressure was proportional to the leaf water loss, and it decreased from @310kPa in recently harvested leaves to zero in dehydrated leaves, after a total water loss of @23%. Turgor pressure was correlated with the other two hydration indexes using approximations of leaf volumetric elastic modules. Similar estimates were obtained because the decline between turgor pressure and the natural logarithm of these relative leaf hydration indexes was numerically similar (@900kPa). However, the volumetric hydration index seemed to be more suitable as a model, not only for being more concise but also because it showed a clearer biomechanical representation of the leaf water deficit effects.

Valoração dos atributos de qualidade do tomate de mesa: um estudo com atacadistas da CEAGESP

A grande variacao no valor do tomate de mesa, do mesmo grupo varietal, mesma classificacao e no mesmo dia de comercializacao, registradas no mercado atacadista da Companhia de Entrepostos e Armazens Gerais de Sao Paulo (CEAGESP), tem entre suas causas mais importantes a diferenca de qualidade entre os atributos destes frutos. O objetivo deste trabalho foi criar uma ferramenta de avaliacao dos atributos de qualidade considerados importantes para o tomate de mesa e a partir da avaliacao destes atributos apontar os mais relevantes na diferenca de valor praticado na comercializacao no mercado atacadista de tomate da CEAGESP. Primeiramente, foram levantados a partir da entrevista com agentes de comercializacao de tomate da CEAGESP os principais atributos, que determinam a qualidade do tomate de mesa. A partir desta respostas, em uma segunda etapa, foi criado um gabarito visual de avaliacao da qualidade a ser utilizado como ferramenta de avaliacao das causas da diferenca de valor. Por fim, na terceira etapa, foram levantados os lotes de tomate de mesa do grupo Saladete, longa vida de coloracao final vermelha, de preco maximo e os de preco minimo para tres classificacoes (graudo, medio e miudo) comercializados no mesmo dia e avaliados os seus atributos de qualidade por dois sistemas: sistema I - avaliacao dos atributos de qualidade por meio de notas de desempenho de acordo com o gabarito visual, e o sistema II - levantamento da frequencia de ocorrencia de cada atributo avaliado no lote de tomate. Os atributos que determinam a qualidade do tomate, segundo os agentes de comercializacao de tomate da CEAGESP, sao: o tamanho (tipo ou calibre), a coloracao do fruto, a ausencia de defeitos, durabilidade, embalagem e sabor. Constatou-se que a diferenca media entre os precos maximos e minimos, nos dias levantados, foi maior para o tomate classificado como miudo (196%), seguido do medio (106%) e graudo (44%). Os atributos determinantes na explicacao da variacao de precos avaliados pelo sistema I sao embalagens paletizaveis (caixa com dimensoes externas que permitam o empilhamento em palete, 1,00 m por 1,20 m, e com furos laterais que permitam a boa circulacao de ar) e embalagens que proporcionem um adequado empilhamento (encaixe perfeito das embalagens, suporte adequado do produto pela embalagem, pilha regular e firme), enquanto que, para o sistema II, estes atributos sao: frutos sem danos superficiais de casca e protecao adequada da embalagem contra injurias mecânicas. A metodologia empregada para a valoracao dos atributos de qualidade de lotes de tomate de preco maximo e minimo, com utilizacao do gabarito visual mostrou ser uma boa ferramenta de gestao da competitividade e de diferenciacao de valor Abstract

Eficácia de limpeza durante o beneficiamento do tomate de mesa

A etapa de limpeza em uma linha de beneficiamento para tomate de mesa e importante, pois e responsavel pela retirada de impurezas externas dos frutos, sem danificalos. O objetivo deste trabalho foi avaliar a eficacia da limpeza e a qualidade dos frutos apos serem submetidos a esse processo, alterando o tipo de cerdas e as rotacoes das escovas utilizadas, tendo como modelo referencial o tomate de mesa Debora. Os ensaios foram realizados em laboratorio, na etapa de limpeza do prototipo UNIMAC1. Primeiramente, identificou-se entre as metodologias, analise com colorimetro e turbidimetro, a mais adequada para avaliar a eficacia de limpeza. Para isto utilizou-se esferas de borracha, de peso similar ao tomate, que foram sujas artificialmente e passaram pela limpeza no prototipo com cerdas de nylon e rotacao de 100 rpm. Em uma segunda etapa, avaliou-se a eficacia de limpeza, utilizando as esferas de borracha, variando-se o tipo de cerda (nylon, sisal, Tereftalato de polietileno - PET e fibra de coco) e a rotacao (40, 80, 120 e 160 rpm) das escovas. E por fim, realizou-se o estudo com o tomate de mesa, analisando a eficacia da limpeza e a qualidade dos frutos (perda de massa, atividade respiratoria, concentracao de etileno e aparencia externa). Observou-se que a analise com o turbidimetro foi a mais precisa na avaliacao da eficacia de limpeza. No ensaio com as esferas, o uso de cerdas mais flexiveis, nylon e sisal, que apresentam um indice de flexibilidade (Gc) de 68,34 e 70,27 N.m-1, respectivamente, combinadas a altas rotacoes tornaram o processo de limpeza mais eficaz. A cerda PET, que e mais rigida, Gc de 135,94 N.m-1, e a rotacao de 40 rpm foram ineficientes, apresentando um indice de limpeza inferior a 50%. Para os frutos de tomate, o tratamento cerdas de nylon a 120 rpm foi o mais eficaz no processo de limpeza, com um indice de limpeza de 91%, ja na rotacao de 160 rpm o indice foi inferior (88%), uma vez que devido a alta velocidade das escovas os frutos pulavam e assim nao eram envoltos pelas cerdas. Os menores indices de limpeza, 75,4 e 78,8% foram obtidos nos tratamentos com fibra de coco a 80 e a 120 rpm, respectivamente. De um modo geral, os frutos limpos apresentaram alta perda de massa, alta atividade respiratoria e um maior incremento na concentracao de etileno apos o processo de limpeza. A limpeza dos frutos nao foi perceptivel na analise sensorial, todavia os tomates que passaram pela limpeza foram os mais aceitos no teste de intencao de compra. Assim concluiuse que a cerda de nylon, por ser mais flexivel, quando combinada a rotacao de 120 rpm, envolveu melhor os frutos, tornando a limpeza mais eficaz. Contudo, tal processo aumentou a perda de massa e a atividade respiratoria logo apos o tratamento. Por outro lado quando combinada a rotacao de 160 rpm, apesar do processo ser mais ineficiente com relacao a limpeza, ocorreu menores alteracoes de qualidade nos frutos. Abstract