Protein and insoluble

Waters, E. J., Peng, Z., Pocock, K. F., and Williams, P. J. (1995). Proteins in white wine, I Procyanidin occurrence in soluble proteins and insoluble protein hazes and its relationship to protein instability. Aust. ]. Grape Wine Res. 1, 86-93. 

Maltose. This sugar is found in suybean. and is produced by the action of ihe enzyme diastase of germinated barley (mall) on starch at 50°C. and is thus an intermediate product in the transformation of starch into alcohol. Maltose CnHiaOn- ILO. melting point IOtf C. when rapidly heated, may be crystallized from the concentrated malt syrup after removal of proteins and insoluble material. Maltose reduces ammonio-cupric salt solulion. and forms osazone. 

Lawrie (1985) classified meat proteins into three types salt-soluble (myofibrillar) proteins, water-soluble (sarcoplasmic) proteins, and insoluble connective tissue proteins. The myofibrillar proteins actin, myosin and actomyosin are the major proteins responsible for determining the heat stability of comminuted meat emulsions. 

Figure 12. Effect of free radical scavenging by cysteine on distribution of glucosamine protein-starch linkages in soluble protein and insoluble residue fraction of wheat flour extrudates. Adapted from (4) with permission. Copyright Amer. Assoc. Cereal Chemists, 1996.

Bomb calorimetry (gross 26, 27 energy, energy from fat) calculation from gross energy, protein, and insoluble dietary fiber values (utilizable energy)... 

Muscle proteins in typical mammalian muscle tissue constitute around 20% of the muscle weight The major proportion of muscle is made up of muscle fibre proteins (elongated, threadlike cells) called myofibrillar proteins. Smaller amounts of soluble sarcoplasmatic proteins and insoluble structural proteins from connective tissue are also present (Table 2.16). Myofibrillar and sarcoplasmatic proteins are almost complete (whole) proteins, while the nutritional value of structural proteins is very low as they are almost indigestible. Table 2.17 gives the amino acid composition of some pure animal proteins Table 2.9 presents the amino acid compositions for the main types of meat proteins. 

Since peanut proteins are very soluble in water in their native state, Sugarman (188) has proposed the simultaneous extraction of oil and proteins from macerated kernels by vigorously mixing the kernels with water and then separating the oil, proteins, and insoluble constituents by centrifugation. 

Keratin is the protein of hair and wool. These proteins are insoluble because of the disulfide cross-linking between cystine units. Permanent waving of... 

Uranium can enter the human body orally, by inhalation, and through the skin and mucous membranes. Uranium compounds, both soluble and insoluble, ate absorbed most readily from the lungs. In the blood of exposed animals, uranium occurs in two forms in equiUbrium with each other as a nondiffusible complex with plasma proteins and as a diffusible bicarbonate complex (242). 

Since the binding of extraneous ions considerably alters the value of lEP of an aminoacid or protein, this point is not a constant. The term isoionic point (IP) is used to designate the pH value of a pure protein in salt-free water. The direct determination of this constant is difficult and because many proteins are insoluble in the absence of salts. The isoionic point is usually determined indirectly, that is, by measuring the lEP at different concentrations of the neutral salts and extrapolating to zero concentration The value of the isoionic point may differ from lEP by more than a pH unit (Haurowitz 1963). 

Solubility of protein in water varies within wide limits. While some proteins dissolve easily in salt-free water, others dissolve only in the presence of certain concentrations of salts, a third group is soluble in mixtures of water and ethanol, and insoluble in any solvent. 

Just like in coiled-coils, p-sheet secondary structure (Fig. 2) is ubiquitous in natural examples and in proteins and biomaterials. Alzheimer s disease is characterized by fibrillar amyloid plaques in the cerebral parenchyma. The insoluble amyloid fibrils are predominantly formed upon conformational switching of the 42 amino acid... 

Polyphenols are ubiquitous in all plant organs where they are found as monomers or in polymerised forms (Schofield et al, 2001). In addition to the beneficial effect of poljq)henols, they also bind minerals and precipitate proteins and carbohydrates, in effect reducing the nutritive value of foods. Polyphenols have been classified for nutritional purposes into extractable and non-extractable types (Bravo, 1998). Extractable polyphenols are low-and intermediate-weight phenolics while non-extractable polyphenols have high molecular weight and are insoluble in normal solvents. 

Because of their very complex chemical structures and heterogeneity, melanins are difficult to extract, separate, and characterize from tissues. Eumelanins are insoluble in water and organic solvents. They can be extracted from tissues with strong chemicals that are capable of removing lipids, proteins, and other tissue components but also lead to the formation of degradation products. Enzymatic procedures were developed for the isolation of eumelanins from mammalian hair and irises. The first step is sequential digestion with protease, proteinase K, and papaine in the presence... 

Denaturation is a change in which the natural protein becomes insoluble in solutions in which it was previously soluble. It is brought about by physical means such as heat, pressure, and surface force, or by chemical means, although very few chemical agents are used in this connection in the food field. Gel-type solutions are usually beaten before they become too thick or firmly set. As air is incorporated, the volume increases and the firmness of the gel stabilizer sets the foam. 

Texturization is not measured directly but is inferred from the degree of denaturation or decrease of solubility of proteins. The quantities are determined by the difference in rates of moisture uptake between the native protein and the texturized protein (Kilara, 1984), or by a dyebinding assay (Bradford, 1976). Protein denaturation may be measured by determining changes in heat capacity, but it is more practical to measure the amount of insoluble fractions and differences in solubility after physical treatment (Kilara, 1984). The different rates of water absorption are presumed to relate to the degree of texturization as texturized proteins absorb water at different rates. The insolubility test for denaturation is therefore sometimes used as substitute for direct measurement of texturization. Protein solubility is affected by surface hydrophobicity, which is directly related to the extent of protein-protein interactions, an intrinsic property of the denatured state of the proteins (Damodaran, 1989 Vojdani, 1996). 

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