الفهرس 
Definition of ProbioticsOnly 14 pages are availabe for public view
 |  | from | 198 |  |  |
| | | from | 198 | | |
Abstract
Recently fermented dairy milk products and their role in the diet of
people gain paramount importance around the world. Kefir is one of the
fermented dairy products; it becomes increasingly popular in recent years
due to its health benefits on humans. For this reason, this study concerned
with the production of different types of kefir products with different
probiotic microbial strains and analysis its chemical, physical, rheological
characteristics, sensory evaluation as well as it’s antimicrobial activity
aginst G(-ve), G(+ve) bacterial strains and candida albicans.
- The probiotic bacterial and starter culture inocula were prepared by the
following concentrations: lactobacillus helveticus by total inoculum of
(3%), Lactococcus lactis + Lactococcus cremoris by total inoculum of
(1%), Streptococcus thermophiles + Lactobacillus bulgaricus +
Lactobacillus acidophilus + Bifidobactrium lactis by total inoculum of
(3%) while the probiotic yeast starter cultures (Saccharomyces cerevisiae
(ATCC 943), Saccharomyces boulardii (ATCC 2366) and Kluveromyces
marxianus (ATCC 36142) were prepared by the concentration of 1%.
- The preparation of different types of kefir products (T1-T8) have
required the inoculation of sterilized low- fat milk (1.1%) with different
concentrations of different mixed microbial starter cultures (3, 4, 5, and
6%). Each type of kefir product was prepared with the same type of
probiotic bacterial starter cultures and difference in the type and
concentration of probiotic yeast starter culture.
- The obtained results of chemical characteristics revealed that the total
solids, protein ,ash contents increased with the increase of concentration
of the inoculated mixed microbial starter cultures; the highest value of
protein content ranged from 4.51 to 4.85% and accompanied with the
highest concentration of mixed microbial starter culture (6%). On the
other hand, the lactose content and fat contents decreased as the
concentration of mixed microbial starter cultures increased from 3 to 6%.
The physical characteristics of different types of kefir products indicated
the fluctuation of pH values in a range from 4.48 to 5.52.
- The moisture content decreased with the increase of concentration of
mixed microbial starter cultures.
The syneresis and penetration characteristics of different prepared kefir
products showed inverse relationship while the kefir products T5 and T6
gave the best score of sensory evaluation. The obtained results indicated
that the different types of kefir products had the strong inhibitory effect
against each of G (-ve) bacteria (Escherichia coli (ATCC 8739) and
Salmonella enteritides (ATCC 14028) and G (+ve) bacteria
Staphylococcus aureus (ATCC 25923) and Bacillus subtilus
(ATCC6633) and Candida albicans (ATCC 10231). There was a gradual
increase of the mean of inhibition zone in parallel with the increase of
concentration inocula from 3- 6% in eight different kefir products, i.e the
concentration inocula of 6% accompanied with the highest inhibitory
effect against the five different pathogenic microbial strains, especially in
the kefir type,T6.
- To investigate the health benefits of different types of kefir products
(within a concentration of inocula 6%) on human, female western rats
were obtained from the Research Institute of Ophthalmology, Giza.
Animals were housed in individual cages at room temperature (about
25°C ±5). The basal diet consisted of protein (10%), corn oil (10%),
cellulose (10%), salt mixture (4%), vitamin mixture (1%) and starch
(65%). After one week (adaptation period), rats reached an approximately
weight of 135-140 gm and divided into two groups as follo
A-Preventive group, group of rats fed on different eight prepared kefir
products for 28 days and injected with colonic carcinogenic agent 1, 2
dimethylhydrazine-dihydrocholoride (40mg/ kg). These rats were left for
the 10 days.
B-Therapeutic group, group of rats fed on different eight prepared kefir
products for 28 days after induction of disease.
-After feeding the rats on different types of kefir products their serum
tumor marker CA 19.9, lipid pattern parameters including total
cholesterol, HDL, and LDL cholesterol, and so liver, kidney functions as
well as essential mineral ( K,Ca and Na) ,random glucose were evaluated.
Also, their five organs liver, kidney, spleen, colon and intestine were
weighted, and the colon organ was subjected to histological and
histopathological analysis.
-The obtained results revealed that body weights and organs weights in
preventive group were highly significantly increased (P< 0.01) during the
experimental period before injection, while after injection the values of
body and organs weights were less than these values in therapeutic group
of rats.
-Biochemical analysis showed that tumor marker CA 19.9 values in
preventive group of rats were significantly decreased (P< 0.05) compared
to the therapeutic group of rats.
-Total cholesterol and LDLc values were significant decreased (P< 0.05)
in preventive group especially in rat groups fed on kefir products
T2,T3,T5,T7,while in other rat groups fed on (T1, T6,T8 ) the cholesterol
values had no change. Also high density lipoprotein cholesterol (HDLc)
values had significantly increased (P< 0.05) in preventive group in
compare to therapeutic group; it had a constant value among rat groups
fed on kefir product T6. Random blood glucose values increased among
rat groups fed on kefir products T1 and T4, and it decreased among rat
groups fed on kefir products T2, T3, T5, T6, T8, also it exhibits a
constant value in group of rats fed on kefir product T8.
- The results showed significantly increase (P< 0.05) of potassium and
sodium values among group of rats in preventive group. While calcium
values had not significant difference (P> 0.05)
- Creatinine, urea, and uric acid values were significantly decreased among
group of rats in preventive group.
- Liver functions, GOT, GPT and alkaline phosphatase levels showed
significantly decrease (P<0.05), while protein levels showed significantly
increase (P< 0.05) among groups of rats in preventive.