Date post: | 25-Jun-2015 |
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PLANT BASED PROTEINS
presented by
Sethulakshmi k v
Plant proteins
*SOY PROTEIN *COTTON SEED PROTEINS *RAPE SEED• WHEAT GLUTEN• CURN ZEIN• KAFIRIN (GRAIN SORGHUM)• OAT AVENIN• RICE BRAIN PROTEIN (RBP)• LUPIN• PEANUT PROTEIN
WHEAT GLUTEN
Wheat gluten is composed of amixture of complete protein molecules that can be separated in the glutenins and gliadins on the basis of their extractability in aqueous ethanol.
Wheat gluten is produced by washing wheat flour extensively with water. The main part of the starch is washed out and collect. Other water soluble substances such as albumin proteins are also, at least to some extent, removed. The final vital wheat gluten is rich in protein, but also contains water, starch, fiber, fat and ash. Wheat protein consists of two types based on ethanol solubility
Lower molar mass gyliadins are ethanol soluble Higher molar mass glutenins are not soluble in ethanol.
In general, the gliadin/glutenin ratio is ~3/2
During extensive shearing or heating the protein polymerizes which implies that gliadins with intramolecular sulfur – bonds crosslinks intermolecular and hence produces large molecules.
CORN ZEIN Zein is a protein biopolymer that is renewable and
can be extracted from corn and corn coproducts. As with gliadin, zein prolamine is insoluble in water, except at very low or
high pH, but is soluble in ethanol. Corn zein consists of monomers and disulfide-linked oligomers. Because
of its lack of essential amino acids and its water insolubility the main
interest lately has been to use it as an industrial protein.. Zein has an amphiphilic character where the main chain has polar amino
acids but the side chains contain more than 50% nonpolar amino acids, including leucine, isoleucine, valine, alanine, phenyl alanine and glycine.
The most common zein aminoacids are glutamic acid (glutamine) 21-26%, leucine (20%), proline (10%) and alanine (10%)
This Protein can be divided in various ways, and one example shows two
major fractions; the α zein which includes ~80% of the available prolamine and is defined as the fraction being soluble in 95% ethanol, and β-zein, which is relatively unstable, but is soluble in water.
α-Zein, which is the most abundant prolamin in corn, is also the most widely used.
It was determined that α zein was the only zein present in zein produced industrially (Wilson 1988).
This fraction has a unique amino acid sequence and structure that allows for many industrial uses.
α-Zein contains >50% nonpolar amino acid residues and contains 9–10 tandem repeats of helical segments of these nonpolar residues linked by polar turns high in glutamine
The commercial use of corn zein includes numerous applications
Zein has had a variety of applications: plastics, coatings, inks, chewing gum, adhesives, and fibers, etc.
Coating
Fiber and biodegradable films and plastics
Specific examples include hairs fixatives, , labels,
varnishes, microspheres, coatings on confectionery and nuts. IN
the 1970s almost 75% of the 500 tons of produced zein was
used to coat tablets.
For several applications the yellow colour of zein, due to xanthophylls and carotenoids, is unattractive. Several ways of reducing the colour have been tested and one way to get relatively white zein is to start with waxy corn, which contains less pigment and xanthophyll.
zein films have been explored for coatings in numerous food applications.
Medical field
Micro and nanoparticles of zein have been studied as carriers of nonpolar drugs; microspheres of zein have been produced that contain Ciprofloxacin, an antibiotic
Recently, biomedical field and controlled self-assembly has seen newer applications of zein. Many of these new processes need purified decolorized and deodorized zein
Dong et al (2003) grew human liver cells (HL-7702) and mice fibroblast cells (NIH3T3)
on zein films and used polylactic acid (PLA) and Corning microplates as control. Zein films were produced from zein particles that agglomerated upon drying.
Applications of protein nanostructures on food processing and safety, functional beverage, and biomedical engineering.Various nano-/micro- structures formed by zein self-assembly
are being investigated for different applications. For examples, core-shell structures are of interest for
encapsulation purposes in delivery systems of food, beverage, pharmaceutical, and cosmetics industries, and
nanoporous structures are potential scaffolds for bone and tissue regeneration
Zein is promising for tissue work because it has high tensile strength to support the cells
. The zein film with the smallest zein particles produced from the solvent (0.3% w/v) showed the best results for proliferation of both cells after three days
The ability to produce decolorized and deodorized zein has allowed application of extremely pure zein in the medical field for tissue technology and cell growth
Nanoporous structures are potential scaffolds for bone and tissue regeneration
KAFIRIN (GRAIN SORGHUM)
Kafirin is the prolamine of the staple crop sorghumgrown in the semi arid parts of South Africa.
It has properties similar to zein, but is more hydrophobic and less digestable.
Films can be cast from aqueous ethanol (70 wt %) solutions after heating to 700C.
An example of a plasticizer system for kafirin is a mixture of glycerol, polyethylene glycol and lactic
acid.
Oats are considered the sixth most important crop in
the world. Avenin is the oat prolamine and is most
soluble in 45wt % ethanol, hence being more hydrophilic
than other prolamines.
It is worth pointing out that kafirin, zein and avenin are
considered safe with respect to celiac decease.
Glycerol – plasticized avenin films have been cast from
45 wt % ethanol solution by first heating the solution to
700C for 15 min.
OAT AVENIN
Unfractionated rice bran protein consists of a mixture of albumin,
globulin, prolamin and glutelin. Rice bran is produced in large
quantities as a co-product/by product from rice milling.
It has good nutritional quality and superior protein efficiency ratio.
Adebiyi et al. have cast films based on RBP at various pH,
plasticizer content and with or without thermal denaturation. It was
shown that the strongest films were made with heat treatment under
alkaline conditions. As with other proteins, casting should be carried
out some distance from the isoelectric point, which is low for RBP.
RICE BRAN PROTEIN
LUPIN
The seeds from lupin, a leguminous plant, can be
used to make films. The seeds are rich in protein, oil
and nonstarch polysaccharides and oligosaccharides
of the raffinose family.
The protein has a good balance of essential amino
acids.
A lupin seed protein isolate can be obtained by
essentially grinding the seeds, removing the fat,
extraction/precipitation and freeze-drying.
PEANUT PROTEIN
It is possible to cast bio-based films based on peanut proteins. Cast films with
peanut protein isolate and glycerol plasticizer from a basic 900C solution.
Whereas the peanut seed contains 45% lipid and 22~33% protein, the peanut
protein isolate contains significantly more protein and less fat (protein
content>95g/100g).
Films or solutions were exposed to different physical treatments (hear,
ultrasound, UV irradiation) or chemical treatments with acetic anhydride, succinic
anhydride, form-aldehyde or glutaraldehyde in order to improve the properties of
the final products.
It was shown that strength values in excess of 1 Mpa were obtained with the
heat treatment (especially at 700C), 24h UV exposure, ultrasonication using a
water bath or the addition of the aldehydes. It was shown that the water vapor
barrier was improved by heat treatment (60-900C) and the use of the aldehydes.
The oxygen barrier was improved using the heat treatment or UV (ultrasound
was not evaluated here.) Interestingly, the anhydrides did not improve the
mechanical or the barrier properties.
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