• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Master's Dissertation
DOI
Document
Author
Full name
Vera Lucia Bellucci
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 1991
Supervisor
Title in Portuguese
Efeito das condições de armazenamento no pH, acidez titulável, sobrevivência e atividade proteolítica de culturas láticas
Keywords in Portuguese
ACIDEZ
ARMAZENAMENTO
ATIVIDADE ENZIMÁTICA
BACTÉRIAS LÁTICAS
ENZIMAS PROTEOLÍTICAS
IOGURTE
MICROBIOLOGIA DE ALIMENTOS
PH
TEMPERATURA
Abstract in Portuguese
Para o levantamento das mudanças ocorridas no iogurte em termos de acidez titulável, atividade proteolítica, pH e sobrevivência das bactérias láticas durante o armazenamento foi utilizado leite tipo C fortificado com leite desnatado desidratado (Molico, Nestlé) para que atingisse 16% de extrato seco total (EST). Esse leite recebeu um tratamento térmico (20 min, vapor fluente em autoclave), e então, foi resfriado até atingir aproximadamente 45°C. Após o resfriamento, o leite foi inoculado com Lactobacillus delbrueckii subsp. bulgaricus e/ou Streptococcus salivarius subsp. thermophilus (MARSHALL, 1987) isolados de iogurte comercial (Chambourcy e Paulista) e incubado a 42°C ± 1 por 4 horas. Após o período de incubação do lei te (4 horas), a coalhada sofreu 2 tipos de resfriamento, rápido (banho de gelo) e lento (refrigerador), e após atingir a temperatura de armazenamento (3, 7 e 12°C), e a cada cinco dias do mesmo, foram retiradas amostras da coalhada cara determinação das mudanças acima citadas, durante 25 dias. A análise estatística dos resultados mostrou que a variação da acidez titulável, atividade proteolítica, pH e sobrevivência não foram significativas para as 3 temperaturas empregadas durante os 25 dias de armazenamento.
Title in English
The effect of storage conditions on the titratable aciditv, proteolytic activitv, pH and survival of lactic acid cultures
Abstract in English
This work was undertaken to study the changes in the titratable acidity, proteolytic activity, pH and survival of lactic acid starter cultures isolated from commercial of yogurts, on controlled storage conditions. Commercial pasteurized milk fortified to 16% ETS with skim milk powder was heat treated by steam flow for 20 min. After cooled to ± 45.0°C, the milk was inoculated with L. delbrueckii subsp. bulgaricus and/or S. salivarius subsp. bulgaricus isolated from commercial yogurt (Chambourcy and Paulista), and incubated at 42.0 ± 1°C for four hours. At the end of incubation, the samples were divided in two lots. One of them was fast cooled in ice bath and the other put into the refrigerator to cool slowly. After that, the samples were storaged in refrigerators at 3, 7 and 12.0°C for 25 days. At every five days of storage, samples were taken and analized for titratable acidity, proteolytic activity, pH and survival of cultures. The statistic analysis of the results showed no significative changes of the parameters analysed, for the 3 temperatures of storage (3, 7 and 12.0°C) for a total of 25 days.
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
BellucciVeraLucia.pdf (2.44 Mbytes)
Publishing Date
2019-11-08
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2020. All rights reserved.