Protein-containing emulsions and adhesives, and manufacture and use thereof
This invention provides emulsions and adhesives comprising proteins that can be isolated from a variety of sources including renewable plant biomass, and methods of making and using such emulsions and adhesives.
1. An isolated polypeptide composition comprising a plurality of water insoluble polypeptides derived from castor meal, castor protein isolate, soy meal, soy protein isolate, canola meal, canola protein isolate, or a combination thereof, wherein the isolated polypeptide composition is capable of dispersing PMDI in water to produce a homogeneous dispersion that is stable, by visual inspection, for at least 5 minutes.
2. The composition of claim 1 , wherein the polypeptide composition comprises one or more of the following features:
(i) an amide-I absorption band between about 1620 cm −1 and 1632 cm −1 and an amide-II band between approximately 1514 cm −1 and 1521 cm −1 , as determined by solid state Fourier Transform Infrared Spectoscopy (FTIR),
(ii) a prominent 2° amide N—H stretch absorption band centered at about 3272 cm −1 , as determined by solid state FTIR,
(iii) an average molecular weight of between about 600 and about 2,500 Daltons, and
(iv) two protonated nitrogen clusters defined by 15 N chemical shift boundaries at about 86.2 ppm and about 87.3 ppm, and 1 H chemical shift boundaries at about 7.14 ppm and 7.29 ppm for the first cluster, and 1 H chemical shift boundaries at about 6.66 ppm and 6.81 ppm for the second cluster, as determined by solution state, two-dimensional proton-nitrogen coupled NMR.
3. The composition of claim 1 , wherein the polypeptide composition is dispersible in water.
4. The composition of claim 1 , wherein the polypeptide composition is isolated by extraction under neutral or basic conditions, by enzyme digestion, or a combination thereof.
5. The composition of claim 1 , wherein the composition is substantially free of primary amines, carboxylic acids, amine salts, and carboxylate salts.
6. The composition of claim 1 , wherein the water insoluble polypeptides are derived from castor meal.
7. The composition of claim 1 , wherein the water insoluble polypeptides are derived from castor protein isolate.
8. The composition of claim 1 , wherein the water insoluble polypeptides are derived from soy meal.
9. The composition of claim 1 , wherein the water insoluble polypeptides are derived from soy protein isolate.
10. The composition of claim 1 , wherein the water insoluble polypeptides are derived from canola meal.
11. The composition of claim 1 , wherein the water insoluble polypeptides are derived from canola protein isolate.