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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.
1

Processamento e estabilidade de nectares de acerola-cenoura

Quinteros, Edwin T. Torres 06 March 1995 (has links)
Orientador: Hilary Castle de Menezes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-07-20T09:55:49Z (GMT). No. of bitstreams: 1 Quinteros_EdwinT.Torres_M.pdf: 2560623 bytes, checksum: 5385199c71d4bcd4fac9a0167b470051 (MD5) Previous issue date: 1995 / Resumo: Foi investigada a estabilidade de duas formulações de néctares aceroia-eenoura, denominadas I e II, processadas a escala piloto e depois armazenadas sob condições ambientais durante um período de seis meses. Às mudanças nas características químicas, fisico-químicas, microbiológicas e sensoriais foram determinadas através de análises e controles de qualidade periódicas. O néctar I foi preparado usando 30% de suco de acerola, 30% de suco de cenoura e 40% de xarope de Sacarose de 20°Brix, enquanto que, o néctar II foi feito com 25% de suco de acerola, 35% de suco de cenoura e 40% de xarope de sacarose de 22 °Brix. Durante a estocagem as perdas de a-caroteno foram de 39% no néctar I e de 25% no néctar II. As perdas de a-caroteno foram de 48% e 39% para I e II, respectivamente. Em ambos os casos, as perdas aconteceram, sobretudo nos dois primeiros meses. Quanto ao ácido ascórbico, as perdas mensais foram de 6,55% e 6,01% para I e II, respectivamente, ocorrendo a maior velocidade de perda nos três primeiros meses, provavelmente pelo mecanismo aeróbico. Algumas características dos néctares tais como o pH, ºBríx, acidez titulável, açúcares redutores e não redutores permaneceram inalterados durante o período do estudo. Pelos controles microbiológicos não se detectaram presença de microorganismos. Os provadores julgaram como aceitáveis o sabor e a cor dos dois néctares. Não houve diferença significativa ao nível de 5% entre as aceitabilidades dos néctares em nenhum dos teste sensoriais. A equipe de juizes também não detectou mudanças significativas desses atributos sensoriais no decorrer do armazenamento. Consequentemente, baseados nos resultados obtidos pode-se afirmar que a vida-de-prateieira dos néctares estudados vai além dos seis meses / Abstract: The stability of two formulations of a mixed west Indian cherry/carrot nectar were investigated. The nectars, denominated I and II, were processed on a pilot plant scale and stored under environmental conditions for six months. Changes in the chemical, physico-chemical, microbiological and sensory characteristics were determined at intervals during the storage period. Nectar I was prepared using 30% west Indian cherry juice, 30% carrot juice and 40% of a 20°B sucrose syrup- Nectar II consited of 25% west Indian cherry juice, 35% carrot juice and 40% of a 22°B sucrose syrup. During storage, the a-carotene content of nectar I decreased by 39%, whereas that of nectar II decreased by 25%. The losses in a-carotene were 48% and 39% for nectars I and II respectively. In both cases the losses occurred mainly during the first two months. With respect to the ascorbic acid content, the average monthly losses were 6.55% and 6.01% for nectars I and II, respectively, occurring at a greater rate during the first three months, probably due to aerobic mechanisms. The characteristics of pH, °B, titratable acidity and reducing and non-reducing sugars remained stable during the storage of both nectars. No microorganisms were detected in the microbiological assays. The flavour and colour of both nectars were considered acceptable by the judges in the sensory analyses. No significant difference in the sensory characteristics was detected between the two nectars at the 5% level of probability, and nor were significant changes observed during storage. It was concluded that both formulations were acceptable and that the shelf life of the nectars was at least six months / Mestrado / Mestre em Tecnologia de Alimentos

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