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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Atuação do 1-metilciclopropeno na pós-colheita de caquis 'Rama Forte' e 'Kyoto' / 1-metilciclopropene activity in the post-harvest of 'Rama Forte' and 'Kyoto' persimmons

Cábia, Nathalie Cardoso [UNESP] 06 December 2016 (has links)
Submitted by NATHALIE CARDOSO CABIA null (nccabia@gmail.com) on 2017-01-31T17:19:43Z No. of bitstreams: 1 Nathalie Cardoso Cábia Tese.pdf: 2151127 bytes, checksum: 60d4e1411e5b512e9d366d8cdd972d67 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-03T18:41:36Z (GMT) No. of bitstreams: 1 cabia_nc_dr_bot.pdf: 2151127 bytes, checksum: 60d4e1411e5b512e9d366d8cdd972d67 (MD5) / Made available in DSpace on 2017-02-03T18:41:36Z (GMT). No. of bitstreams: 1 cabia_nc_dr_bot.pdf: 2151127 bytes, checksum: 60d4e1411e5b512e9d366d8cdd972d67 (MD5) Previous issue date: 2016-12-06 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O caqui é um fruto climatérico altamente perecível, e para estender o período de sua comercialização se faz necessário o uso de métodos de conservação pós-colheita. O presente trabalho teve como objetivo avaliar a qualidade físico-química e enzimática de caquis ‘Rama Forte’ e ‘Kyoto’ tratados com 1-metilciclopropeno (1-MCP). Os frutos após a colheita foram selecionados e expostos a diferentes concentrações de 1-MCP (0 ppb, 500 ppb, 1000 ppb e 1500 ppb) e após o procedimento foram armazenados sob refrigeração a 0 ± 0,5ºC e 90 ± 5% de UR. Foram realizadas análises de perda de massa fresca, taxa respiratória, acidez titulável, potencial hidrogêniônico (pH), sólidos solúveis, índice de maturação (“Ratio”), firmeza, índice de adstringência, ácido ascórbico, açúcares redutores, coloração, capacidade antioxidante, compostos fenólicos totais, atividade das enzimas polifenoloxidase (PFO), poligalacturonase (PG) e pectinametilesterase (PME). As análises foram realizadas nos frutos a cada 7 dias, ao longo de 35 dias de armazenamento refrigerado. O delineamento utilizado foi inteiramente casualizado, com 3 repetições por tratamento. Nas condições em que o trabalho foi realizado pode-se concluir que a aplicação de 1-MCP associada ao armazenamento refrigerado foi eficiente no controle do amadurecimento dos caquis ‘Rama Forte’ e ‘Kyoto’. Em caquis ‘Rama Forte’ não destanizados a dose que apresentou melhores resultados foi a de 1500 ppb de 1-MCP. Em caquis ‘Rama Forte’ submetidos à destanização o 1-MCP, independente da dose, mostrou-se eficiente. Já em caquis ‘Kyoto’, a dose que apresentou melhores resultados foi a de 1500 ppb de 1-MCP. / Persimmon is a highly perishable climacteric fruit, and to extend the commercialization period, is necessary to apply post-harvest conservation techniques for its marketing. The objective of this work was to evalueate the physical-chemical and enzymatic quality of ‘Rama Forte’ and ‘Kyoto’ persimmons using 1-metylcyclopropene (1-MCP). Harvested fruits were selected and exposed to different concentrations of 1-MCP (0 ppb, 500 ppb, 1000 ppb and 1500 ppb) and then, they were stored under refrigeration at 0 ± 0,5°C and 90 ± 5% RH. Analyses were conducted to determine the weight loss, respiration, titratable acidity, pH, soluble solids, maturation index (“Ratio”), firmness, astringency index, reducing sugar, ascorbic acid, antioxidant activity for DPPH, total phenolic compounds, polyphenol oxidase activity, poligalacturonase and pectin. The analyzes were carried out on the fruits every 7 days, during 35 days of refrigerated storage. The experiment was completely randomized, with three replicates each treatment. Under conditions in wich the work performed can be concluded that the application of 1-MCP associated witch cold storage was effective in ripening controlling of 'Rama Forte' and 'Kyoto' persimmons. In persimmons 'Rama Forte' witch tannin, the dose that presented the best results was 1500 ppb of 1-MCP. In ‘Rama Forte’ persimmons submitted to destanizacion 1-MCP, regardless of the dose, was efficient. In ‘Kyoto’ persimmons, the dose that presented the best results was 1500 ppb os 1-MCP.
32

Pós-colheita de uvaia: caracterização de acessos e estádios de maturação / Postharvest of uvaia: characterization of accessions and maturation stages

Thaís Pádua de Freitas 23 June 2017 (has links)
A uvaia (Eugenia pyriformis Cambess) é uma espécie nativa do Brasil, pertencente à família das mirtáceas, que se destaca por possuir um fruto de sabor e aroma agradável. No entanto, ainda faltam informações básicas, principalmente em relação a variabilidade existente em populações e sobre a fisiologia pós-colheita. Nesse contexto, este estudo objetivou caracterizar 31 acessos de uvaia originados de semente, quanto aos aspectos físicos, químicos e compostos bioativos e avaliar a influência do estádio de maturação na qualidade pós-colheita. O estudo foi dividido em duas etapas. Na primeira, caracterizou-se a variabilidade dos acessos baseado nos atributos físicos e químicos. Foram realizadas análises de massa fresca, massa de sementes, diâmetro, formato, cor da casca, rendimento de polpa, sólidos solúveis, acidez total titulável, ácido ascórbico, compostos fenólicos, carotenoides, flavonoides e capacidade antioxidante. Na segunda, avaliou-se a qualidade pós-colheita de uvaias colhidas em três estádios de amadurecimento quanto a cor da casca, sólidos solúveis, acidez titulável, ácido ascórbico, flavonoides, carotenoides, compostos fenólicos, capacidade antioxidante e compostos voláteis, respiração (CO2) e produção de etileno (C2H4). Entre os acessos foi verificada ampla diversidade na coloração dos acessos, variando de amarelo claro a alaranjado, com frutos classificados majoritariamente como achatados. Os atributos que apresentaram maior variação entre os acessos foram os sólidos solúveis, ácido ascórbico, compostos fenólicos e a capacidade antioxidante. Os resultados do armazenamento, mostraram que os frutos verdes alcançaram a mesma cor da casca, teor de acidez titulável, ácido ascórbico, flavonoides, carotenoides, compostos fenólicos e atividade antioxidante dos frutos maduros. Por outro lado, frutos colhidos verdes apresentaram baixo teor de sólidos solúveis e menor variedade de compostos voláteis. Não foi identificada relação entre o estádio de amadurecimento e a respiração. A produção de etileno foi diretamente proporcional ao estádio de amadurecimento. Estas informações sobre a qualidade da fruta colhida em diferentes estádios podem auxiliar a escolha daquele que melhor atender as exigências de uso para o consumo in natura e para a elaboração de produtos. / The uvaia (Eugenia pyriformis Cambess) is a native species of Brazil, belonging to the family Myrtaceae, which stands out for having a fruit of pleasant taste and aroma. However, basic information is still lacking, especially in relation to the variability in populations and their postharvest physiology. In this context, this study aimed to characterized 31 accessions of uvaia (propagated by seeds), as to physical, chemical and bioactive compounds and to evaluate the maturity stage influence on postharvest quality. The study was divided in two parts. First, was characterized the variability of the accessions based on physical and chemical attributes, were analyzed: fresh mass, seed mass, diameter, shape, skin color, yield of pulp, soluble solids, total titratable acidity, ascorbic acid, phenolic compounds, carotenoids, flavonoids and antioxidant capacity. Second, was evaluated the postharvest quality of uvaia at three stages of maturation as to skin color, soluble solids, titratable acidity, ascorbic acid, flavonoids, carotenoids, phenolic compounds, antioxidant capacity and volatile compounds, respiration (CO2) and production of ethylene (C2H4). There was a wide diversity in the color of the accessions, varied from light yellow to orange, with fruits classified mainly as flattened. The highest variation among the accessions was observed in the attributes of soluble solids, ascorbic acid, phenolic compounds and antioxidant capacity. During storage, the fruits picked green achieved the same color of the skin, titratable acidity, ascorbic acid, flavonoids, carotenoids phenolic compounds and antioxidant activity of mature fruits. On the other hand, fruits harvested green exhibited low content of soluble solids and less variety of volatile compounds. There was no relationship between respiratory rate and ripening. Ethylene production was proportional to the ripening stage. This information on the quality of the fruit harvested in different stages can help to choose the one that best meets the requirements of use for fresh consumption and for the elaboration of products.
33

CaracterizaÃÃo fisica, fisico-quÃmica e enzimÃtica de frutos de seis cultivares de coqueiro anÃo em diferentes estadios de desenvolvimento / Phisical phisic-chemical, and enzimatic characterization of fruits of six dwarf coconut cultivars at different stages of development

Vlayrton Tomà Maciel 14 February 2008 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O presente trabalho objetivou caracterizar as alteraÃÃes fÃsicas nos frutos e fÃsico-quÃmicas, enzimÃticas e sensoriais na Ãgua de coco de seis cultivares de coqueiro anÃo em sete estÃdios de desenvolvimento. As cultivares analisadas foram: AnÃo Verde de Jequi (AVeJ), AnÃo Amarelo de Gramame (AAG), AnÃo Amarelo da MalÃsia (AAM), AnÃo Vermelho de CamarÃes (AVC), AnÃo Vermelho da MalÃsia (AVM), sendo os frutos colhidos em um campo experimental da Embrapa Meio Norte (ParnaÃba, PI) nos seguintes estÃdios de desenvolvimento: 126, 147, 168, 189, 210, 231, 252 dias apÃs a abertura da inflorescÃncia. Logo apÃs a colheita, os frutos foram conduzidos para o laboratÃrio de Fisiologia e Tecnologia de PÃs-colheita na Embrapa AgroindÃstria Tropical, em Fortaleza, CearÃ, onde foram feitas as anÃlises fÃsicas e fÃsico-quÃmicas. Parte das amostras foram armazenadas a -85ÂC e, em seguida, transportadas para o LaboratÃrio de Fisiologia Vegetal, do Departamento de BioquÃmica e Biologia Molecular da Universidade Federal do CearÃ, onde foram feitas as anÃlises enzimÃticas. O experimento seguiu um delineamento inteiramente casualizado, em esquema fatorial do tipo 6 x 7,. Foram feitas as caracterizaÃÃes fÃsicas individuais dos frutos (massa, comprimento maior, diÃmetro, volume da Ãgua e cor da casca), e em seguida, as avaliaÃÃes fÃsico-quÃmicas da Ãgua de coco: sÃlidos solÃveis totais (SS), aÃÃcares solÃveis totais (AST) e redutores (AR), acidez total titulÃvel (ATT), relaÃÃo SS/ATT, pH, turbidez e proteÃna). Foram, tambÃm, avaliadas as atividades das enzimas que oxidam fenÃis [polifenoloxidase (PFO) e peroxidase especÃfica para o guaiacol (G-POD)], bem como aquelas do ciclo do ascorbato-glutationa [dismutase do superÃxido (SOD), catalase (CAT) e peroxidase do ascorbato (APX)], sendo tambÃm determinados alguns atributos sensoriais da Ãgua de coco. Os resultados deste experimento mostraram que as cultivares AVM, AAG e AAM, podem ser exploradas comercialmente, devido Ãs qualidade fÃsicas e fÃsico-quÃmicas que apresentaram. Pode-se concluir tambÃm que, independente da cultivar, o melhor perÃodo para colheita encontra-se na faixa de 189 a 210 dias de desenvolvimento dos frutos, pois nesse perÃodo as cultivares analisadas apresentaram os melhores atributos de qualidade.. NÃo foi detectada atividade da G-POD na Ãgua de coco de nenhuma das cultivares. A atividade da SOD na Ãgua de coco aumentou nos estÃdios iniciais de desenvolvimento dos frutos de todas as cultivares, destacando-se as cultivares AVG e AVeJ como as que apresentaram maiores atividades dessa enzima. A CAT mostrou-se a principal enzima eliminadora de perÃxido de hidrogÃnio da Ãgua de coco e sua atividade variou muito com o desenvolvimento dos frutos e tambÃm entre as cultivares / This study aimed at characterizing in fruit and physico-chemical, and sensory enzyme in the coconut water the of six dwarf coconut cultivars at seven stages of development. The studied cultivars were: Green dwarf from Jequi (GDJ), yellow dwarf from Gramame (YDG), yellow dwarf from Malaysia (YDM), Red dwarf from Cameroon (YDC), Red dwarf from Malaysia (RDM), Red dwarf from Gramame (RDG). Fruits were harvested from an experimental field, Embrapa Meio Norte (Parnaiba city, Piauà State), at the following stages of development: 126, 147, 168, 189, 210, 231, and 252 days after the opening of the inflorescences. Upon harvest, fruits were taken to the Laboratory of Postharvest physiology and technology at Embrapa Agroindustria Tropical, located in Fortaleza, CearÃ, were the physical and physic-chemical analyses were performed. Part of the samples were stored at -85ÂC and then transported to the Laboratory of Plant Physiology, Biochemistry and Molecular Biology Department from The Federal University of CearÃ, were the enzymatic study was conducted. The experimental designed was a completely randomized one in a factorial scheme 6 x 7. First physical characterization (mass, length, diameter, water volume, and color of the shell) was individually performed for each fruit, then the physic-chemical analyses of coconut water: total soluble solids (TSS), total soluble sugar (TSSu), reducing sugars (RS), total titratable acidity (TTA), sugar to acid ratio (TSS/TTA), pH, turbidity, and protein. It was also evaluated the activities of enzymes that oxide phenols [polyphenoloxidase (PFO) and peroxidase specific for the guaiacol (G-POD)], as well as those of the cycle of ascorbate-glutathione [superoxide dismutase (SOD), catalase (CAT) and the ascorbate peroxidase (APX). Moreover some of the sensory aspects of the water were evaluated. The results showed that the YDR, YDG, and RDG may be commercially exploited, due to their physical and physic-chemical characteristics. It was also concluded that, the best time for harvesting is somewhat between 189 to 210 days after fruit developed set, since right at this time the studied cultivars presented the best quality attributes. There was detected activity of G-POD in the coconut water from any of the cultivars. The activity of SOD in the coconut water increased in the early stages of development of the fruits of all the cultivars, such as RDG and YDG cultivars such as those that showed higher enzyme activity. A CAT proved to be the main enzyme eliminating of hydrogen peroxide of coconut water and its activity varied greatly it the development of the fruit and also between the cultivars
34

Conservação de goiabas 'Pedro Sato' tratadas com 1-metilciclopropeno: concentrações e tempos de exposição. / Conservation of ‘Pedro Sato' guavas treated with 1-methylcyclopropene: concentrations and exposure time.

Bassetto, Eliane 22 January 2003 (has links)
O objetivo deste trabalho foi verificar os efeitos de concentrações de 1-metilciclopropeno (1-MCP) em tempos de exposição na conservação de goiabas 'Pedro Sato'armazenadas sob condição ambiente e sob refrigeração. No primeiro experimento as goiabas foram tratadas com 0, 60, 120 e 240 nL.L -1 de 1-metilciclopropeno durante 3, 6 e 12 horas e armazenadas a 10ºC durante 14 e 21 dias (+ 2 dias a 25ºC). No segundo experimento as goiabas foram tratadas com 0, 100, 300 e 900 nL.L -1 de 1-metilciclopropeno durante 3, 6 e 12 horas e armazenadas a 25ºC. No terceiro experimento as goiabas foram tratadas com 0, 100, 300 e 900 nL.L -1 de 1-metilciclopropeno durante 3 horas e armazenadas a 25ºC e a 10ºC. No primeiro experimento as características físico-químicas foram avaliadas aos 14 e aos 21 dias após os tratamentos. No segundo experimento as características foram avaliadas quando os frutos atingiram o completo amadurecimento. No terceiro experimento as características físico-químicas foram avaliadas aos 2, 4, 6 e 8 dias de armazenamento para os frutos armazenados a 25ºC e aos 4, 8, 12 e 16 dias de armazenamento para os frutos armazenados a 10ºC. Os frutos tratados com 240 nL.L -1 de 1-MCP durante 6 e 12 h e armazenados durante 14 dias a 10ºC apresentaram melhor retenção da coloração da casca e menor incidência de podridão, porém quando colocados por 2 dias a 25ºC apesar de apresentarem melhor firmeza e menor incidência de podridões, não mantiveram a cor verde da casca. O 1-MCP não foi eficiente em retardar o amadurecimento dos frutos tratados nas concentrações de 60, 120 e 240 nL.L -1 e armazenados a 10ºC. A concentração de 300 nL.L -1 de 1-MCP durante 6 e 12 h e a concentração de 900nL.L -1 durante 3 horas, permitiram a conservação dos frutos por 9 dias sob condição ambiente. A aplicação de 1-MCP nas concentrações de 100, 300 e 900 nL.L -1 retardou o amadurecimento dos frutos armazenados tanto no ambiente como sob refrigeração. O tratamento com 900 nL.L -1 de 1-MCP durante 3 horas foi considerado o mais eficiente em retardar o amadurecimento dos frutos nas duas temperaturas de armazenamento. Este tratamento permitiu a conservação dos frutos por 16 dias em ambiente refrigerado. / The objective of this study was to study the effect of 1-methylcyclopropene (1-MCP) concentration and exposure time treatments on the postharvest conservation of 'Pedro Sato' guava fruits at room temperature and at refrigerated storage conditions. Three different experiments were carried out. In the first, guava fruits were treated with 0, 60, 120 or 240 nL.L -1 of 1-methylcyclopropene for 3, 6 or 12 hours and stored at 10ºC for 14 and 21 days (plus 2 days at 25ºC). In the second, the guava fruits, were treated with 0, 100, 300 or 900 nL.L -1 of 1-methylcyclopropene for 3, 6 or 12 hours and stored at 25ºC. In third, the guava fruits were treated with 0, 100, 300 or 900 nL.L -1 of 1-methylcyclopropene for 3 hours and stored at 25ºC and at 10ºC. The physical-chemical characteristics of the fruits were evaluated at 14 and 21 days, when the guavas fruits were completely ripen, and at the days 2, 4, 6 and 8 of storage for fruits stored under room temperature and at days 4, 8, 12 and 16 of storage for fruits storage under refrigerated conditions for the first, second and third experiment, respectively. Fruits treated with 240 nL.L -1 of 1-MCP for 6 and 12 hours stored for 14 days at 10ºC showed better retention of skin color and smaller decay incidence, although the fruits stored for 2 days at 25ºC showed better firmness and smaller decay incidence, all of the fruits not maintain green skin color. The 1-MCP concentrations of 60, 120 or 240 nL.L -1 and 10ºC storage conditions were not efficient on delaying treated fruit ripening. The concentration of 300 nL.L -1 of 1-MCP for 6 and 12 h, and the concentration of 900 nL.L -1 for 3 hours, allowed the better conservation of the fruits for 9 days at room temperature. 1-MCP was efficient on delaying fruits ripening under room temperature storage conditions. The 1-MCP 100, 300 or 900 nL.L -1 concentrations treatments delayed the ripening of fruits stored under room temperature and under refrigerated conditions. The 900 nL.L -1 of 1-MCP for 3 hours treatment was considered to be the most efficient on delaying fruits ripening in the both storage temperatures conditions. Also this treatment allowed conservation of the fruits for 16 days under refrigeration.
35

Effects of Pre- and Post- Harvest Applications of 6-Furfurylaminopurine and N6-Benzyladenine on Physio-Chemical Changes in Lettuce

El-Mansy, Hussein Ibrahim 01 May 1964 (has links)
The extent and nature of physio-chemical changes that take place in detached leaves after harvest and during storage have been reviewed and discussed by Osborne (1962) and Rogers (1955). These changes include loss of moisture (Wittwer et al., 1962), chlorophyll degredation (Person et al., 1957), Protein loss (Thimann and Manmahan, 1960), and result in subsequent appearance of the visual manifestations of senescence of plant tissues. As lettuce, like most leafy vegetables, deteriorates rapidly and steadily after harvest. Loss of quality is inevitable and can only be minimized by rapid handling and with the best possible storage conditions (Pratt et al., 1954). In recent years, abundant work has been done to delay senescence by the use of various chemicals. Among the investigated chemicals, kinetin (6-furfurylarninopurine) and its related c ompounds show some promise. Van Overbeek et al. (1941) reported a potent new growthpromoting factor (kinetin) in coconut milk. This chemical is active in causing many of the growth reactions of c oconut milk at exceedingly small dosages. Subsequently several arninopurine compounds were synthesized. One of which is SD 4901 (Verdan), N6-benzyladenine, an experimental senescence inhibitor, was developed by Shell Development Company, Modesto, California in 1960. Many reports showed that this chemical is capable of delaying senescence of plant tissues on the basis of restoring protein molecules and respiration inhibition. On the other hand, others have shown stimulation of respiration and delaying of senescence. Paucity of scientific literature on the stability of those chemicals on leafy vegetables gave impetus to a study of the comparative influence of pre- and post-harvest applications of 6-furfurylaminopurine and N6-benzyladenine as related to successive harvest times. Such studies may have considerable economic bearing upon storing and shipping leafy vegetables to distant markets. This thesis presents effects of different concentrations (5, 10, and 20 ppm.) of pre- and post-harvest applications of 6-furfurylaminopurine and N6-benzyladenine as related to three successive harvest times (at one week intervals) on chlorophyll content, moisture content, total nitrogen, insoluble and soluble nitrogen, oxygen uptake, 0 and co2 production during storage (at 40 Fo and 85 percent RH) of "Great Lakes" variety of lettuce.
36

An investigation of the physiological and biochemical responses elicited by Panulirus cygnus to harvesting, holding and live transport.

Spanoghe, Patrick T. January 1996 (has links)
The western rock lobster (WRL), Panulirus cygnus is a decapod crustacean which is found in abundance in the coastal waters of Western Australia and which supports a major fishery of economic importance for the State, with an annual harvest ranging between 10-12 million kilograms. The growth of the existing markets in Asia for live exports and the competition exerted by other countries marketing spiny lobsters prompted the need for the Industry to assess and develop post-harvest handling procedures likely to contribute to an improved quality of live product. The physiological responses of P. cygnus to handling and transportation were virtually unexplored.The objectives of this project were, (i) to generate information with regard to the biological phenomena underlying morbidity and mortality of lobsters during live export shipments, (ii) to investigate the physiological responses of P. cygnus to the post-harvest handling practices currently used by the WRL industry in their five export program and, (iii) to identify protocols by which post-harvest handling techniques could be modified to reduce the occurrence of morbidity and mortality during five export.These objectives were achieved through, (i) a field survey conducted during the course of the 1992/93 fishing season, investigating the relative influence of environmental factors and processing techniques on the incidence of lobster morbidity+mortality during simulated live shipments and, (ii) a series of field experiments that monitored the physiological responses elicited by lobsters to post-harvest handling procedures and simulated live shipment conditions.From the field survey, it appeared that the rate of morbidity+mortality experienced in simulated live shipments, within the three processing units surveyed, averaged 5.22 +/- 0.63 %, with a highly significant difference (p [less than] 0.001) between the ++ / processing units. Scrutiny of the data revealed a major influence of two factors directly related to post-harvest handling procedures: a) the time spent under normal commercial conditions in packaging export cartons and, b) the ambient temperature within the export cartons. Following 30-36 hrs in packaging, the percent mortality increased twofold, from 5.2 +/- 0.0 % recorded following 20 - 24 hrs to 10.4 +/- 2.3%. With regard to the ambient temperature within the export carton, temperatures between 17.5 and 20.0 degrees celsius appear to be optimal for P. cygnus survival while temperatures above 20.0 degrees celsius induce significantly greater morbidity and mortality.A number of factors were identified as having a potential influence on lobster physiological responses to post-harvest handling conditions:a)Immediately after harvesting, lobsters are subjected to a range of transport environment options, according to their origins: i.e., (i) direct delivery from fishing vessels by local fishermen to the processing facility, (ii) onshore transportation by truck from coastal depots and, (iii) transport in baskets on board carrier-boats from the Houtman Abrolhos Islands.b) After delivery, lobsters are subjected to sorting and grading procedures, with a concomitant exposure to air and disturbance.c) Recovery in holding tanks is usually allowed for a period ranging between 24 to 72 hours.d) Prior to being packed in export cartons, lobsters are subjected to a short period (30 sec to 3 min) of immersion in chilled water (8 - 12 degrees celsius), the procedure varying from one processor to the other.e) During subsequent periods of transit in export cartons, (up to 48 hrs) lobsters are subjected to aerial exposure and fluctuating ambient temperature.A comparison of the physiological profiles of lobsters from different origins revealed significant differences, with respect to a ++ / range of physiological variables. On the basis of visual estimates of health status, lobsters from the "local" origin exhibited a consistently superior condition, when compared to "coastal" and "carrier-boat" animals. The examination of physiological variables revealed consistent trends reflecting the visual assessments. "Local" lobsters exhibited significantly lower levels in anaerobic metabolic waste concentrations, with the haemolymph lactate titre between 2.77 +/- 0.19 and 4.33 +/- 0.56 mmol L(subscript)-1, compared with the other groups, between 5.23 +/- 0.24 and 8.86 +/- 1.29 mmol L(subscript)-1. A 250 to 300% increase in haemolymph ammonia concentration was observed between "coastal" and "carrier-boat" groups and the "local" lobsters, at 0.32 +/- 0.02 mmol L(subscript)-1. Significantly higher pH values were recorded for the "local" group, at 7.72 +/- 0.04, compared with values below 7.64 +/- 0.04 for the other groups. "Local" lobsters recorded 8 to 15 times less circulating glucose, at 0.11 +/- 0.03 mmol L(subscript)-1, having 50% more ATP in their muscle tissues, at 6.07 +/- 0.15 mu mol g(subscript)-1 and 250% more arginine phosphate, at 6.56 +/- 0.72 mu mol g(subscript)-1.An assessment of the efficiency of the industry sorting procedures revealed differences between selected and rejected animals with regard to the ATP and arginine phosphate concentrations in their muscle tissues with, as a common trend for both variables, selected animals recorded higher values. Significant differences were identified within the "local" group of lobsters, with selected animals recording 40% more ATP, at 6.92 +/- 0.63 mu mol g(subscript)-1 and 30 % more arginine phosphate, at 7.77 +/- 1.01 mu mol g(subscript)-1.A monitoring of the physiological profiles of lobsters subjected to extended (up to 8 hours) periods of onshore transportation in trucks revealed a significant ++ / reduction in their health status. A consistent and almost linear fall in the concentration of total adenylate (35%), to 5.46 +/- 0.50 mu mol g(subscript)-1 and phosphagen reserve (70%),to 2.77 +/- 0.26 mu mol g(subscript)-1, were recorded throughout the 8 hour period. For up to 6 hours the concentration of lactate in the leg muscle tissues increased by 0.95 mu mol g(subscript)-1 h(subscript)-1 and then by 4.7 mu mol g(subscript)-1 h(subscript)-1,to reach 20.57 +/- 1.61 mu mol g(subscript)-1 after 8 hours. Haemolymph glucose and ammonia titres recorded a 3.5 fold increase over the first 6 hours, to reach 2.14 +/- 0.54 and 1.17 +/- 0.16 mmol L(subscript)-1, respectively, the last period (6 to 8 hours) being characterised by a 1.6 and 1.9 fold decrease in concentration. Lobsters were able to maintain their haemolymph pH close to 7.77 during the first four hours, with a concomitant rise in haemolymph calcium concentration. From the results, it appeared that, under current industry procedures, extending the period during which lobsters are transported in spray trucks to more than 6 hours is conducive of altered physiological status.An assessment of the effects of short periods (up to 60 min) of aerial exposure and disturbance revealed significant changes in the physiological profiles of lobsters. When exposed to air, lobsters exhibited a significant fall in haemolymph pH, a rise in lactate concentration, and a depletion in energy reserves. Lobsters left undisturbed were able to buffer an incipient acidosis for up to 40 min (7.78 +/- 0.03), after which a decline in pH was recorded to reach 7.71 +/- 0.02. Conversely, disturbed animals experienced an uncompensated acidosis and a decrease by 0.7 of a unit over a 60 minute period. Similarly, undisturbed lobsters did not demonstrate behavioural signs of stress while disturbed animals exhibited dramatically diminished responses ++ / to handling after 60 min of exposure. Both disturbed and undisturbed animals recorded a decline in ATP/ADP, to reach after 40 min, 8.31 +/- 0.77 and 5.05 +/- 0.45, respectively, compared to 13.18 +/- 1.69 (control). During the last period (40 to 60 min), the undisturbed animals recorded a 40 % decrease in ATP concentration, to reach 4.42 +/- 0.16 mu mol g(subscript)-1, while a 53% decline was recorded in the disturbed group, to 3.59 +/- 0.41 mu mol g(subscript)-1. During aerial exposure, the phosphagen reserve recorded a 55% decrease in the disturbed animals, at 4.82 +/- 1.37 mu mol g(subscript)-1, compared to 20% in the undisturbed group, at 8.64 +/- 0.87 mu mol g(subscript)-1. A 100% increase in lactate ion concentration was recorded in the muscle tissues of disturbed animals to reach 5.53 +/- 0.49 mu mol g(subscript)-1, compared to a 15% increase in the undisturbed group, at 2.83 +/- 0.29 mu mol g(subscript)-1.The monitoring of the physiological profiles of lobsters during extended periods (up to 72 hrs) of recovery in holding tanks revealed significant shifts in their physiological profiles and that a return to a steady state occurred only after 8 to 48 hours following re-immersion, according to the environmental conditions and the origin of the animals. Resting levels were identified after 24 hours for the haemolymph pH (close to 8.00), for the concentration in lactate, ions in the muscle tissues (2.00 to 3.00 mu mol g(subscript)-1 for the haemolymph glucose titre (0.30 to 0.60 mmol L(subscript)-1), for the haemolymph ammonia titre (close to 0.25 mmol L(subscript)-1), for ATP (6.50 to 7.70 mu mol g(subscript)-1), and for the phosphagen reserve (12.2 to 16.70 mu mol g(subscript)-1). Longer periods ([greater than]/= 48 hrs) were required for full recovery to occur when lobsters were stored at high stocking density and when lobsters were not isolated from their ++ / artificial environment. Extending the recovery period to 72 hrs resulted in slight changes in the physiological profiles of lobsters, with a 20 % decline in ATP/ADP, a 10% decrease in phosphagen concentration in the muscle tissues of the lobsters and subdued behavioural responses for those lobsters held at higher stocking densities.No attempt was made in the present study to establish the resting levels for the physiological variables surveyed. In a number of experiments, "control" groups have been studied and used as reference points to monitor changes accompanying exposure to a range of environmental conditions. The data pertaining to these different groups revealed a variability for most of the variables surveyed, suggesting that it would be hazardous to assume that these animals were undisturbed and to state with confidence that the values recorded for the variables surveyed would represent resting levels.The physiological responses of lobsters subjected to chilling procedures was investigated and significant physiological changes were identified. Short chilling procedures (3 and 6 min) were conducive of a dramatic reduction of the behavioural responses to handling, a reduction in pH values ranging between 0.13 and 0.24 of a unit, a rise in haemolymph lactate concentration by 1 to 2.6 mmol L(subscript)-1, a 20 to 100% increase in haemolymph glucose titre, a 35 to 75% decrease in phosphagen concentration. Extending the chilling period for up to 24 hrs resulted in a progressive return to control levels for most of the physiological variables surveyed. However, physiological signs of disturbance remained perceptible between 2 to 15 hours, as demonstrated by elevated lactate concentrations, lowered ATP and AP concentrations and lowered ATP/ADP values.Lobster body core temperature (CBT) reduction resulting from immersion in chilled water suggested that limited cooling ++ / effects were achieved by using the standard chilling procedures currently used by the WRL industry. Using "A" size lobsters (395 - 453 gr), a reduction of the CBT by 0.5 to 0.8 degrees celsius was recorded after 1 and 3 min immersion in 12 degrees celsius water, highlighting the limited low temperature effect exerted by these procedures in lowering the overall temperature of the mass of the product to be packed into export cartons.A study of the general physiological responses of lobsters to simulated live transport conditions in export cartons was conducted, investigating the effects of the period spent by the animals in export cartons, the effects of environmental temperature and the impact of chilling regimes. No attempt was made to duplicate exactly the conditions of cartons shipped overseas, that is carted by trucks to the airport and then transported by air to foreign markets. This study revealed that during the first 4 hours of transit, the animals exhibited physiological changes probably related to delayed responses to handling, disturbance and chilling procedures, as demonstrated by a decline in pH (0.1 to 0.3 of a unit), a rise in haemolymph ammonia (0.5 to 1 mmol L(subscript)-1) and glucose (0.5 mmol L(subscript)-1) titres, an increase in muscle lactate concentration (0.5 to 1 mu mol g(subscript)-1, a decrease in ATP concentration (1.5 mu mol g(subscript)-1, and a partial replenishment of the phosphagen reserve. These changes were less pronounced for those lobsters which underwent intermediate (30 min) chilling treatments.The subsequent periods (to 48 hours) were characterised, for all the treatments, by a rise in lactate concentration in the muscle tissues, this response being delayed for those lobsters which underwent a "6 min" or "30 min" chilling treatment. The data suggested that moderate changes in haemolymph lactate titre resulted from the increase ++ / in muscle lactate concentration, up to values ranging between 6 and 8 mu mol g(subscript)-1, beyond which levels, haemolymph lactate rose dramatically, to reach values up to 19.98 mmol L(subscript)-1. The ATP concentration remained relatively constant up to 18 - 26 hours, after which a steep decline was recorded to reach values below or close to 4 mu mol g(subscript)-1 after 42 hours, suggesting that the adenylate pool was maintained, probably through aerobic and anaerobic pathways of energy generation and by the "buffering" role played by the phosphagen reserve. After 24 to 36 hours, all the lobsters exhibited signs of energy depletion, as demonstrated by the changes in ATP/ADP ratio. A concomitant increase in lactate ion concentration and a decrease in haemolymph glucose titre was recorded, suggesting that anaerobic metabolism had become the major component of energy production. Simultaneously, a marked increase in the internal carton temperature was identified, which probably induced an increase in the metabolic rate of the lobsters. This "temperature effect" was delayed for up to 32-38 hrs transit, for those lobsters which underwent intermediate (30 min) and extended (24 hrs) chilling treatments. The changes in haemolymph pH and calcium titre suggest that the initial decline in pH identified at the completion of the first 4 hours of transit was, at least partially, compensated after 26 - 32 hours. A 30 to 40% increase in haemolymph calcium titre was recorded after 4 hours of transit, suggesting that bicarbonate ions were released in order to buffer the pH of the haemolymph. However, a decrease in pH (0.1 to 0.3 of a unit) was recorded during the subsequent periods suggesting that the bicarbonate buffering capacity did not suffice to match the recorded massive rise in lactate titre.By extending the duration of the chilling procedures and by using refrigerated ++ / material (wood-shaving fillers, ice-bottles), lower temperatures were achieved inside the packaging cartons and these were maintained for longer periods of transit (up to 20 hours), delaying the effect of the external environment on the temperature changes recorded inside the cartons and the concomitant metabolic responses of the animals. This effect was also achieved by maintaining the cartons in controlled temperature environments ([less than] 20 degrees celsius) and, to a lesser extent, by improving the insulation capacity of the polystyrene cartons.This study constitutes an overview of the physiological responses of Panulirus cygnus to post-harvest handling procedures currently used by the WRL industry. It revealed that an improved return for the Industry could be achieved by reducing the debilitating effects exerted on the lobsters by handling, exposure to air and elevated environmental temperature. It provides direction for future research, aimed at improving the quality and hence, the financial return in the live export of WRL.
37

Mathematical modelling and improvement of operating practices of sun drying of rice : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Phylosophy [i.e. Philosophy] at Massey University

Meas, Pyseth Unknown Date (has links)
In Cambodia, sun drying of rice has always been of great importance for preserving rice. The main goal of this study was to find the conditions for sun drying that maximise the throughput while minimising quality loss. A whole-bed approach was taken to investigate the conditions of the grain and the air at different layers during the drying process. Seven sets of sun-drying experiments were conducted in Cambodia using a range of methods practiced by rice farmers. These methods included drying with different bed depths (2 to 6 cm), with the bed on different pads (water-proof tarpaulin, mat, net, polystyrene or rice husk), and with different bed tempering methods (stirring regularly or shading and/or covering the bed around midday) for four Cambodian rice varieties (Pka Knhey, CAR11, Masary and IR66). The grain temperature was found to be more affected by the solar intensity than the temperature of the ambient air. Fastest drying was achieved when the bed was thin, less compacted, stirred regularly but not shaded or covered around midday, dried on a pad which allows some air and moisture movement and with high or strong solar intensity. Only the mechanical impact (MI) and milling tests of the rice quality provided useful results. Higher quality was found for grain that was dried in thin beds, stirred regularly, shaded with or without covering around midday and dried on pads with less air circulation. Among the methods used to determine the glass transition temperature of the grain, only the Differential Scanning Calorimetry method gave meaningful results. The glass transition temperature data were highly variable but generally decreased with increasing moisture content and compared quite well with the published glass transition temperatures for other varieties of rice. To provide additional detail on the local conditions within the bed, to better understand the drying process and the interactions between variables and to predict alternative parameters that might be used to correlate with the head rice yields (HRYs), a mathematical model for heat and moisture transport within the bed was developed. The model covered all the drying methods/conditions studied experimentally. A lumped parameter approach to energy and mass transfer in individual kernels was used in the bed model. The model was validated against experimental data. The predicted drying time, temperatures, moisture contents and water activities (relative humidity of the air within the bed) were found to compare very well with the experimental data except when a polystyrene pad was used. The model proved to be a very good mechanistic tool with advantages of simplicity and practical accuracy in the design and management of the sun drying system. A number of parameters related to postulated grain damage mechanisms were derived from the predicted conditions within the bed during drying. The best predictors of the grain quality were found to be rewetting the kernels when the grain is bulked (especially when the kernels are partly below and partly above critical moisture content) grain temperature and distance from the glass transition temperature line. It was concluded that in order to get the fastest drying conditions rice should be sun dried with thin bed, stirring, not shaded or covered around midday and dried on a pad with air circulation. For the highest quality grain, that is grain which would have the least breakage during milling, rice should be sun dried with a thin bed, stirring, shaded or covered around midday and dried on a pad with less air circulation. The optimal drying conditions to get the best quality combined with the fastest practical drying rate, the drying conditions should be drying with 2 cm bed depth, stirring the grain bed every hour, shading or covering the bed around midday and using a tarpaulin or net pad placed directly on the ground.
38

Drying characteristics of Saskatoon berries under microwave and combined microwave-convection heating

Reddy, Lakshminarayana 20 March 2006
The study on dehydration of frozen saskatoon berries and the need for dried fruits has been strategically identified in the prairies. Our motivation was to find a suitable method for dehydration in order to extend saskatoon berry shelf life for preservation. Microwave, convection and microwave-convection combination drying processes were identified to finish-dry saskatoon berries after osmotic dehydration using sucrose and high fructose corn syrup (HFCS) sugar solutions. Osmotic dehydration removes moisture in small quantities and also introduces solutes into the fruit that acts as a preservative and also reduces the total drying time. <p>Due to the very short harvesting season of saskatoon berries, an accelerated process like microwave combination drying can bring down the moisture to safe storage level, immediately after harvest. Untreated and osmotically dehydrated berries were subjected to convection (control), microwave and microwave-convection combination drying conditions at different product drying temperatures (60, 70 and 80C) until final moisture content was 25% dry basis. A laboratory-scale microwave combination dryer was developed, built with temperature and moisture loss data acquisition systems using LabView 6i software. Thin-layer cross flow dryer was used for convection-only drying and for comparison. <p>Drying kinetics of the drying processes were studied and curve fitting with five empirical equations including Page equation, was carried to determine drying constant, R2 and standard error values. The microwave-combination drying method proved to be the best for drying saskatoon berries. Dehydrated product quality analysis by means of color changes, rehydration ratio measurements and observed structural changes with scanning electron microscope technique were the factors in drying method selection for saskatoon berries.<p> This research was instrumental in the modification and development of a novel drying system for high-moisture agricultural materials. Microwave-convection combination drying at 70oC, yields good results with higher drying rates and better end-product quality.
39

Characterization of seed coat post harvest darkening and condensed tannin accumulation during seed coat development in common bean (<i>Phaseolus vulgaris</i>)

Elsadr, Hanny Tarek 09 May 2011
Seed coat biochemistry and colour are highly variable in common bean (Phaseolus vulgaris) (syn. dry bean). Genetic studies of dry bean seed coat chemistry and colour have important implications in breeding efforts for improving nutrition and seed quality for consumer acceptance. The results of this thesis detail the phenotypic and genotypic characterization of seed coat post harvest darkening (PHD) in parents and progeny of crosses among them as well as the phenotypic characterization of seed coat condensed tannin (CT) accumulation in five genotypes of bean.<p> Seed coat PHD represents a problem for producers and consumers of several different market classes of dry bean. There are three post harvest darkening phenotypes: (i) non-darkening (ND), (ii) slow darkening (SD) and (iii) regular darkening (RD). The inheritance of PHD was determined by evaluating 28 populations derived from crosses between RD, SD and ND genotypes. Results suggest that at least two major, unlinked genes control the PHD trait in dry bean. Recessive epistasis with three phenotypic classes best explains the segregation ratios observed in populations from crosses between SD and ND parents. One gene, J, is responsible for whether a bean will darken and seeds of plants that are jj do not darken at all. Another gene, SD, influences the rate a seed coat will darken with seed from sdsd individuals darkening more slowly that those with the dominant SD allele. Quantitative evaluation of seed coat PHD demonstrated that there was a wide range of darkening within any given PHD phenotype. Crosses made between the ND x ND cross class resulted in F2 progeny that were all ND, however, a wide range of seed coat background colours was noted in the progeny. In several of the crosses made between ND x RD and SD x RD classes the resulting F1 progeny were all RD; however, a wide range of RD phenotypes were observed in the F2 progeny. These phenotypes are not likely due to quantitative trait loci (QTL) associated with the PHD trait, but rather a result of other chemical reactions occurring in the seed coat. Condensed tannins (CT; syn. proanthocyanidins), kaempferols, polyphenol oxidase (PPO) and possibly other compounds or enzymes may be interacting and causing this quantitative range within any given genotype as a function of environmental variability, genotype and their interaction. CT have been associated with PHD but are not responsible for the major difference between RD and SD lines. They may, however be responsible for the quantitative nature of the phenotype.<p> Condensed tannins can be harmful or beneficial to human health and the environment depending on the amount present and where it is found in the plant. Manipulating the production, accumulation and form of CT in the seed coat of dry bean would be beneficial to bean producers, consumers and breeders. This experiment quantitatively and qualitatively evaluated differences in patterns of CT accumulation in the seed coats of five genotypes of dry bean which exhibited low, medium or high concentrations of CT in their seed coats at maturity. Condensed tannin content was assessed from seeds harvested every other day from 6 40 days after flowering (DAF) using a modified BuOH-HCl assay. Results illustrated that CT accumulated as early in low CT genotypes as in high CT genotypes. CT content stabilized after 14 DAF in low CT genotypes. By contrast, CT content peaked then leveled off 30 DAF in moderate and high CT genotypes. A reduction in CT content in the higher CT lines was observed in the final stages of seed development.
40

Drying characteristics of Saskatoon berries under microwave and combined microwave-convection heating

Reddy, Lakshminarayana 20 March 2006 (has links)
The study on dehydration of frozen saskatoon berries and the need for dried fruits has been strategically identified in the prairies. Our motivation was to find a suitable method for dehydration in order to extend saskatoon berry shelf life for preservation. Microwave, convection and microwave-convection combination drying processes were identified to finish-dry saskatoon berries after osmotic dehydration using sucrose and high fructose corn syrup (HFCS) sugar solutions. Osmotic dehydration removes moisture in small quantities and also introduces solutes into the fruit that acts as a preservative and also reduces the total drying time. <p>Due to the very short harvesting season of saskatoon berries, an accelerated process like microwave combination drying can bring down the moisture to safe storage level, immediately after harvest. Untreated and osmotically dehydrated berries were subjected to convection (control), microwave and microwave-convection combination drying conditions at different product drying temperatures (60, 70 and 80C) until final moisture content was 25% dry basis. A laboratory-scale microwave combination dryer was developed, built with temperature and moisture loss data acquisition systems using LabView 6i software. Thin-layer cross flow dryer was used for convection-only drying and for comparison. <p>Drying kinetics of the drying processes were studied and curve fitting with five empirical equations including Page equation, was carried to determine drying constant, R2 and standard error values. The microwave-combination drying method proved to be the best for drying saskatoon berries. Dehydrated product quality analysis by means of color changes, rehydration ratio measurements and observed structural changes with scanning electron microscope technique were the factors in drying method selection for saskatoon berries.<p> This research was instrumental in the modification and development of a novel drying system for high-moisture agricultural materials. Microwave-convection combination drying at 70oC, yields good results with higher drying rates and better end-product quality.

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