Production of microbial
polysaccharides for use in food
are patents (especially in
Japan) related to the use of Ganoderma, Agaricus
and other mushroom glucans in
edible fi lm coatings and water-soluble
capsules, for example inclusion
of pickling liquids in soups and sauces
(Laroche and Michaud, 2007) and a great
potential exists for future food
applications.
16.2.3 Yeast polysaccharides
Although most microbial
polysaccharides derive from fungi and bacteria,
Saccharomyces cerevisiae ,
probably the most common food grade yeast in
fermented food and drinks, is
known for the production of a food-related
glycan which is extracted from
yeast cells walls. Cell wall polysaccharides
are usually insoluble in water,
but their solubility and properties can readily
be altered by chemical or
enzymatic derivatization and facilitate their use
in foods or pharmaceuticals.
BYG is the general term for commercialized
‘brewer’s yeast glucan’ (or more precisely
glycan), which may also contain
non-carbohydrate moieties,
produced from S. cerevisiae. BYG is effi
cient in
improving the physical
properties of foods as a thickening and water-hold-ing agent, or as a fat
replacer giving a rich mouthfeel, and it also enhances
gel strength in solutions, when
used alone or in combination with other food
grade polymers, such as
carrageenan (Reed and Nagodawithana, 1991; Xu
et al., 2009). Firm gels of BYG
can be formed after heating and subsequent
cooling of solutions above
5–10% concentration. The glycan also has emul-sifying properties and is
reported to improve the organoleptic characteris-tics of the foods where it is
added (Sandford, 1982). Thammakiti et
al. (2004)
studied the production of such
a β-glucan with a β-(1,3)-glucose backbone
chain and a minor branch (about
3%) of β-(1,6)-glucose with an
additional
4.5–6.5% protein content from spent brewer’s yeast
after alkali extraction
from homogenized cell walls,
which had potential applications in food as
an emulsion stabilizing agent,
as it exhibited high viscosity and water
holding and oil binding
capacities.
Baker’s yeast glycan is a
similar product composed of d-glucose
and
d-mannose in 3 : 2
ratio and used mainly as stabilizer/emulsifi
er in dressings
and desserts (Robbins and
Seeley, 1977, 1978; Sandford, 1982). The same
yeast has also been studied and
utilized for the production of therapeutic
glucans (Williams et al., 1992). The wild type strain of S. cerevisiae excretes
an extracellular β-(1,3)-
d-glucan with a degree of branching (DB) of 0.2,
and a genetically modifi ed
strain produces PGG (also known as Betafectin),
a commercial bioactive
(1,6)-β-d-glucopyranosyl-(1,3)- β-d-glucopyranose
glucan with DB of 0.5 which has
several pharmaceutical properties (Jamas
et al., 1991; Wakshull et al., 1999; Kim et al., 2006). In
addition, S. cerevisiae
is the industrial producer of
zymosan, a complex immunoactive and anti-infl amatory glycan (proteoglucan)
comprising a cell wall β-glucan with
long
(1,3)- and (1,6)-glucosyl groups, in conjunction
with mannan, protein and
nucleic acid (Ohno et al.,
2001; Goodridge et al., 2009). These
health-
وجلوكان الفطر الصالحة للأكل الأخرى في الطلاء LM فاي وللذوبان في الماء،كبسولات، على سبيل المثال إدراج تخليل السوائل في الحساء والصلصات(لاروش وميشو، 2007) وجود إمكانية كبيرة للأغذية المستقبلالتطبيقات.السكريات الخميرة 16.2.3على الرغم من أن معظم الجراثيم السكريات المستمدة من الفطريات والبكتيريا،الخباز خميرة، وربما كان الغذاء الصف الخميرة الأكثر شيوعا فيومن المعروف الأغذية والمشروبات المخمرة، لإنتاج الغذاء ذات صلةيتم استخراج غليكان التي من جدران خلايا الخميرة. السكريات جدار الخليةوعادة ما تكون غير قابلة للذوبان في الماء، ولكن ذوبان وممتلكاتهم يمكن بسهولةيمكن تغييرها حسب المادة الكيميائية أو الإنزيمية الاشتقاق وتيسير استخدامهافي الأطعمة أو الأدوية. BYG هو مصطلح عام لأغراض تجارية'غلوكان الخميرة' (أو أكثر غليكان بالضبط)، والتي قد تحتوي أيضا علىغير الأنصاف الكربوهيدرات، المنتجة من خميرة S.. BYG هو ايفي آاف فيتحسين الخواص الفيزيائية للأغذية وسماكة وكيل المياه الانتظار جي، أو على شكل بديل الدهون إعطاء المذاق الغني، وكما أنه يعزز
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