Starch protein effects

Grain legumes have also been processed into refined starch (10,11) and protein isolates (12,13,14) by procedures derived from the traditional corn starch and soybean protein industries (15). However, comparative data on product yields, composition and losses have not been published. A commercial plant for the wet processing of field pea into refined starch, protein isolate and refined fiber has been established in Western Canada. Little is known about the characteristics of the protein isolate or refined fiber product. Water-washed starch prepared from the air-classified starch fractions of field pea (16,17) and fababean (6) have been investigated for certain physico-chemical and pasting properties. Reichert (18) isolated the cell wall material from soaked field pea cotyledons and determined its fiber composition and water absorption capacity. In addition, the effects of drying techniques on the characteristics of pea protein Isolates have been determined (14). 

Surfactants have been, reprotedly, used to prevent extensive puffing of extruded cereal products. It was found in these studies that surfactants could effectively inhibit gelatinization of cereal starch. However, effect of surfactants on protein texturization has not been reported. Two types of surfactants, sodium stearoyl-2-lactylate and calcium stearoyl-2-lactylate (at levels of 0.2 and 0.4% based on the weight of the flour), were mixed with soy flour prior to extrusion. A yeast protein (Torutein, manufactured by Amoco Inc.), claimed to be an extrusion helper although its function is not known, was added. 

Antibody prepared against SSI effectively neutralized souble SSI activity, but had no effect on either the activities of GBSSI or GBSSII, or even on SSII. Alternatively, antibody prepared against the starch granule-bound proteins effectively inhibited GBSSI activity, but had very little effect on the soluble starch synthases.173... 

Several observations indicate the formation of starch-protein complexes. For instance, starch precipitates serum proteins of rabbit, horse, sheep, and chicken.962 This observation seemingly indicates that the complexation has a rather universal character. On the other hand, the type of bonding of proteins from Triticum durum and Triticum sativum is specific for each of these varieties.963 The observed effects may not be associated with complex formation, but they can instead be attributed to the destruction of micelles by dehydration, followed by agglomeration.964 As in the case of starch complexes with sugars, the effect of proteins and cellulose derivatives on starch gelation can be assumed to be the result of the competition for water in solution. As a consequence, swelling is perturbed.965-968... 

Electrophoresis of proteins on starch thin layers,969 starch columns,970 and starch gels971,972 has been reviewed. Partition chromatography of ribo-nucleosides on starch973 and the possibility of making plastics from starch and proteins974 have also been discussed. The effect of protein-starch complexes on the staling of bread was discussed by Hampel.975 All of these studies suggest the formation of starch-protein complexes. 

BERSET 2604 Is a melamine based resin with very low free formaldehyde content. It Is a very effective crosslinker and Insolublllzer for starch, protein, P.V.A., and latex In non-plgmented or pigmented coatings. When BERSET 2604 Is added to the coating color, good wet pick resistance and wet rub improvements are noticeable directly off the machine. 

BERSET 2425 is a melamine based coating insolubilizer. It is a very effective crosslinker for starch, protein, P.V.A., and latex binders in pigmented, or non-pigmented coatings. BERSET 2425 is sufficiently reactive so that 80-90% of insolubilization is achieved directly off the machine and completely developed within a day. Unlike other crosslinkers, BERSET 2425 has little or no effect on coating viscosities. BERSET 2425 has an advantage of having a very low free formaldehyde. 

Hongsprabhas, R, Israkam, K., and Rattanawattanaprakit, C. 2007. Architectural changes of heated mungbean, rice and cassava starch granules Effects of hydrocolloids and protein-containing envelope. Carbohydrate Polymers 67 614—622. 

Kokini, J.L., Baumann, G.C., Bresslauer, K., Chedid, L.L., Herh, P., Lai, L.S. A kinetic model for starch gelatinization and effect of starch/protein interactions on rheological properties of 98 % amylopectin and amylose rich starches. In Spiess, W.E.L., Schubert, H. (eds.) Engineering and Foods, Advanced Process, pp. 109-121. Elsevier/Applied Science Publishers, New York (1990)... 

Xie, F., Dowel, F.E., and Sun, X.S. 2004. Using visible and near infrared reflectance spectroscopy and differential scanning calorimetry to study starch, protein and temperature effects on bread stahng. Cereal Chem. 81(2) 249-254. 

Infusion Method. Infusion is a classic method for top-fermented beers and is used for ad British types. The whole mash is heated graduady from mashing-in to mashing-off with holding times for the degradation of protein and starch. No part of the mash is boiled and the malt, therefore, must be well-modified to assure the breakdown of ad soluble substances. Because no boiling takes place there is no physical breakdown of the malt, and consequentiy infusion is not as effective as decoction despite the better protection of the enzymes. 

The subsequent advance was rather fortuitous and rested more with serendipity than with scientific logic. A search was made for cheaper more effective replacements for casein hydrolysate. Amongst the tested materials was com steep liquor (CSL). CSL is a by-product of the manufacture of starch from maize kemals. Whole maize is incubated in warm water, at 50°C acidified with SO2. Thermophilic bacteria hydrolyse proteins and other components of the kemals, thereby loosening the starch granules. These are removed, leaving behind the steep liquor which is used to treat further maize kemals. Ultimately, the liquor is too viscous to re-use and the liquor is concentrated and used as cattle feed. It was this material that was used for penicillin fermentation. Surprisingly, the yield of penicillin increased by a further 5-10 fold giving yields of 50-100 ig ml. 

Whey may be substituted for starch by as much as 25% in extruded corn snacks, but the product does not puff as much as com alone, as the water-holding whey protein does not react with the starch matrix (Onwulata et al., 1998). WPCs or isolates can be added along with starch to create expanded snack foods with boosted nutritional content however, without texturization, whey proteins in amounts larger than 15% may interfere with expansion, making the products less crunchy. To counter this effect, whey proteins can be texturized with starch to improve their interaction with other food components in a formulation, principally to increase extmdate expansion. In one successful application, between 25% and 35% of the flour was replaced with whey protein (Onwulata et al., 2001a,b). 

Rye Proteins. While rye is the only European cereal able to completely replace wheat in bread, rye protein is not as effective as wheat protein. One reason for this is that as much as 80% of the protein in a rye sour dough is soluble compared with 10% of soluble protein in a wheat dough. One factor that inhibits the formation of a gluten-like complex is the 4-7% of pentosans present, which bind water and raise the viscosity of the dough. The crumb structure is then formed from the pentosans in combination with the starch. 

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