Abstract: The β-glucan produced by Ophiocordyceps dipterigena BCC 2073 is a (1, 3)-β-D-glucan with highly branching O-6-linkedside chains that is resistant to acid hydrolysis (by hydrochloric acid and porcine pancreatic alpha-amylase). This β-glucan can be utilized as a prebiotic due to its advantageous structural and biological properties. The effects of using this β-glucan as the sole carbon source for the in vitro growth of two probiotic bacteria (L. acidophilus BCC 13938 and B. animalis ATCC 25527) were investigated. Compared with the effect of using 1% glucose or fructo-oligosaccharide (FOS) as the sole carbon source, using 1% β-glucan for this purpose showed that this prebiotic supported and stimulated the growth of both types of probiotic bacteria and induced them to produce the highest levels of metabolites during their growth. The highest levels of lactic and acetic acid, 10.04 g·L-1 and 2.82 g·L-1, respectively, were observed at 2 h of cultivation using glucose as the sole carbon source. Furthermore, the fermentation broth obtained using 1% β-glucan as the sole carbon source had greater antibacterial activity against selected pathogenic bacteria (B. subtilis TISTR 008, E. coli TISTR 780, and S. typhimurium TISTR 292) than did the broths prepared using glucose or FOS as the sole carbon source. The fermentation broth obtained by growing L. acidophilus BCC 13938 in the presence of β-glucan inhibited the growth of B. subtilis TISTR 008 by more than 70% and inhibited the growth of both S. typhimurium TISTR 292 and E. coli TISTR 780 by more than 90%. In conclusion, O. dipterigena BCC 2073 is a potential source of a β-glucan prebiotic that could be used for commercial production in the near future.
Abstract: Esterification of p-bromo-m-cresol led to formation of
2-(4-bromo-3-methylphenoxy)acetate (1). 2-(4-Bromo-3-methyl
phenoxy)acetohydrazide (2) is derived from Compound (1) by
hydrazination. Compound (2) was reacted with different aromatic
aldehydes to yield N-(substituted benzylidiene)-2-(4-bromo-3-methyl
phenoxy)acetamide(3a-c). Cyclization of compound (3a-c) with
thioglycolic acid yielded 2-(4-bromo-3-methylphenoxy)-N-(4-oxo-2-
arylthiazolidin-3-yl) acetamide (4a-c). The newly synthesized
compounds were characterized on the basis of spectral studies and
evaluated for antibacterial and antifungal activities.
Abstract: The lactic acid bacteria (LAB) were isolated from
10 samples of fermented foods (Sa-tor-dong and Bodo) in South
locality of Thailand. The 23 isolates of lactic acid bacteria were
selected, which were exhibited a clear zone and growth on MRS
agar supplemented with CaCO3. All of lactic acid bacteria were
tested on morphological and biochemical. The result showed that
all isolates were Gram’s positive, non-spore forming but only
10 isolates displayed catalase negative. The 10 isolates including
BD1 .1, BD 1.2, BD 2.1, BD2.2, BD 2.3, BD 3.1, BD 4.1, BD 5.2,
ST 4.1 and ST 5.2 were selected for inhibition activity
determination. Only 2 strains (ST 4.1 and BD 2.3) showed
inhibition zone on agar, when using Escherichia coli sp. as target
strain. The ST 4.1 showed highest inhibition zone on agar, which
was selected for probiotic property testing. The ST4.1 isolate
could grow in MRS broth containing a high concentration of
sodium chloride 6%, bile salts 7%, pH 4-10 and vary temperature
at 15-45°C.
Abstract: In recent years application of natural antimicrobials
instead of conventional ones, due to their hazardous effects on health,
has got serious attentions. On the basis of the results of different
studies, chitosan, a natural bio-degradable and non-toxic
biopolysaccharide derived from chitin, has potential to be used as a
natural antimicrobial. Chitosan has exhibited high antimicrobial
activity against a wide variety of pathogenic and spoilage
microorganisms, including fungi, and Gram-positive and Gramnegative
bacteria. The antimicrobial action is influenced by intrinsic
factors such as the type of chitosan, the degree of chitosan
polymerization and extrinsic factors such as the microbial organism,
the environmental conditions and presence of the other components.
The use of chitosan in food systems should be based on sufficient
knowledge of the complex mechanisms of its antimicrobial mode of
action. In this article we review a number of studies on the
investigation of chitosan antimicrobial properties and application of
them in culture and food mediums.