This study was carried out to investigate of various
stabilizers on the physicochemical properties of
low fat yogurt and to determine.
The effect of presence of gelatin, pectin and starch with 0.5% and
carrageenan 0.2% in the yogurt had been studied. Many tests techniques
as viscosity, penetration for yogurt gel, whey separation and sensory
evaluation had been established and com
pared.
This study was conducted in order to prolong the period of validity of
yoghurt by adding probiotics consisted of Lactobacillus acidophilus LA-5 and
Bifidobacterium animalis subsp lactis (Bb12) to milk allocated to yoghurt
industry and studied the
microbial, chemical and sensory characteristics of
yoghurt during storage periods for 0, 7،,14, 21, 28, 35 and 42 days at 4 ± 1 °C
and 10 ± 1 °C. The results of microbial characteristics showed that the vital
force of the first starter lasted for 7 days in the control samples while lasted for
35 days for the sample containing Lactobacillus acidophilus LA-5 or
Bifidobacterium animalis subsp lactis (Bb12) when stored at 4 ± 1°C. Adding
probiotics did not affect the taste, smell and pH of the yoghurt without change
in the property values during storage periods. It was also found that the shelf –
life of control samples can be prolonged and consumed safely up to 7 days of
storage while it was prolonged for 35 days in yoghurt samples containing
probiotics.
This study was conducted in order to prolong the period of validity of
yoghurt by adding 5, 10 and 15 g/1 of carrot juice liter during the storage
period of 35 days at 4±°C and 10±1 °C and determine some of the microbial،
chemical and sensory char
acteristics of yoghurt after 1, 7, 14, 21, 28 and 35
days of storage. The results indicated that the vital force had lasted for 7 days
in control samples and 28 days and 35 for samples containing 5, 10 g or 15 g
carrot juice, respectively when stored at 4±1 °C. No significant differences were
observed when samples stored at 10±1 °C. The results also indicated that the
sensory properties of yoghurt containing 5g of the carrot juice were more
favorably than those containing higher proportions due to the absence of taste
and color of carrot juice in the samples. it was also shown the addition of carrot
juice did not affect the pH levels and sensory property values during storage.
Furthermore، shelf-life did not exceed more than 7 days in control samples
while it lasted up to 35 days in yoghurt samples containing carrot juice.
This study was conducted to prolong the period of validity of diluted
yoghurt by adding 0.5g, 0.75g and 1g of garlic per 1liter milk during the
storage period of 50 days at 4 ± 1C °and 10 ± 1C°. Some of microbial, chemical
and sensory parameters o
f yoghurt were identified on weekly bases from 1 till
49 days of the storage period. Results indicated that the vital force as a
microbial parameter was lasted for 7 days in the control samples while it was
lasted with for 35, 42, and 49 days for the samples containing 0.5, 0.75 and 1g
of garlic, respectively when samples stored at 4±1C°. There were no significant
differences in the vital force between control and treated samples when they
stored at 10±1C°. Sensory properties of diluted yoghurt were more favorable in
samples containing 0.5g of garlic (absence of taste and smell of garlic) in
comparison with control samples or with samples containing higher
proportions of garlic. Results also indicated that adding garlic did not affect
either the pH of diluted yoghurt or the values of its sensory properties during
storage periods and increased the safety of consumption up to 49 days of
storage while this safety did not extend behind 7 days in control samples. It was
concludes that adding garlic by 0.5 g/ liter of diluted yoghurt can increase its
shelf life for 49 days.
This research was conducted in the laboratories of Faculty of Agriculture –
Damascus University Department of Food Sciences. The aim of this research
was to study the inhibition effect of the growth and activity of Lactic acid
bacteria as starter
in yoghourt, on the growth of E. coli O157:H7 bacteria. A
pure strains of E. coli O157:H7 and Lactic acid bacteria was used for this study.
The effect of Lactic acid bacteria (Streptococcus thermophilus and
Lactobacillus bulgaricus ) in the number of E. coli O157:H7 was studied in 37 ◦C
and 4◦C. The Lactic acid bacteria was inoculeted in milk which was prepared to
manufacture the yoghurt. The number of E. coli O157:H7 was gradually
decreased with the time. The decline number of this bacteria was clear when S.
thermophilus and Lb. bulgaricus were used as a mixture starter , then when Lb.
bulgaricus was used as a single starter then S. thermophilus was used a single,
In the other hand, the inhibition effect was weaker at 37 C and stronger on 4 C.
This investigation was done in the laboratories of the Faculty of Agriculture
– Damascus University in the Department of Food Sciences. The aim of this
research use to study the inhibition effect of the growth and activity of Lactic
acid bacteria
used as starter and on the growth of Staph. aureus bacteria. Pure
strains of Staph. aureus and Lactic acid bacteria was used the effect of Lactic
acid bacteria (Streptococcus thermophilus and Lactobacillus bulgaricus) on the
number of Staph. aureus was studied at 37 ◦C and 4◦C. The Lactic acid bacteria
were inoculeted in milk for the manufacturing of yoghurt. The number of
Staph. aureus was fixed then was decreased gradually according to time. And
the decreasing number of this bacteria was clear when S. thermophilus and Lb.
bulgaricus were used as a mixture starter, then when was used as a single
starter, Lb. bulgaricus and S. thermophilus.
This research was conducted in the Agriculture Faculty- Food Science
Department, Damascus University, for detecting Lactic acid bacteria isolated
from Syrian dairy products (white fresh cheese-Leben), Samples were collected
from August, 2004 to Oc
tober, 2005 from different areas in Syria. Analysis was
done for 245 bacterial isolates from 40 samples of white fresh cheese and 58
samples of yogurt (curd). Results showed that the genus Enterococcus was
dominant with a percentage of 47.52%; Pediococcus had a percentage of 26.3
%; while Lactococcus had a percentage of 15.38% with only 3.2% for
Lactobacillus.
