Food study functional properties

To develop a model for a particular research experiment to study functional properties of a food protein, the researcher must obviously have some knowledge concerning which factors are potentially important determinants of the level of the functional property to be studied. The researcher must select 1) each of the factors for which there is to be some variation in level within the experiment, 2) the levels to be used for each variable factor, 3) the number of combinations of levels of the different factors to be used, and 4) the level at which each nonvariable, but potentially important, factor is to be set throughout the experiment. 

The number of reports about hemicelluloses that have been covered by this review indicates the significantly increased importance of all types of hemicelluloses as plant constituents and isolated polymers during the last decade. Attention has been paid not only to known hemicelluloses but also to the primary structure, physicochemical, physical, and various functional properties of hemicelluloses isolated from hitherto uninvestigated plants. The efforts to exploit a variety of plant as potential sources of hemicelluloses were pointed out particularly for agricultural crops, wood wastes, as well as for by-products of pulp and rayon fiber technologies. Many studies were devoted to characterize seed-storage hemicelluloses from plants that have been traditionally applied in food and medicine of many underdeveloped countries to find substitutes for imported commercial food giuns. 

The objective of the project described is to obtain insight in the relation between the chemical fine-structure of polysaccharides from soy bean cell walls and their functional properties in industrial products and how they effect processing. Soy meal is of great importance in the feed industry. The application of the (modified) soy bean cell wall polysaccharides as a food additive will be investigated. The obtained knowledge of the polysaccharide structures will also be used in studies concerned with the improvement of the in vivo digestibility of these polysaccharides. 

The present research was conducted to evaluate selected physicochemical properties of the dry roasted and air-classified navy, pinto, and black bean flour fractions. Studies were conducted to determine the chemical composition and to characterize the functional properties of dry-roasted bean flour fractions and to evaluate the suitability of the flours for use in foods systems. 

Makri, E., Papalamprou, E., Doxastakis, G. (2005). Study of functional properties of seed storage proteins from indigenous European legume crops (lupin, pea, broad bean) in admixture with polysaccharides. Food Hydrocolloids, 19, 583-594. 

The functional properties are divided according to a completely different pattern. Enzymic properties are functional ones because the action of the catalyst is, per se, a nonnutri-tional one. In certain cases, when enzymes are added to foods as in vivo digestion aids, they might be considered metabolic enhancers. Otherwise, when used externally to prepare products possessing more utile chemical and physical characteristics, the digestive nature is indubitably a functional property. It must be noted, however, that enzyme functionality usually is not studied in conjunction with the other functionalities, but is a distinct and separate branch of biochemistry involved in functional evaluation. Theoretically, a more scientific division of the functional properties could be made into molecular and non-molecular ones. (Enzymic properties would then be a division of the former.) However, traditional lines already have been set and the proposed division is closer to present research d i sci piines. 

Protein is utilized in many foods for the particular characteristics that it contributes to the final product (1 ). In order for protein products to maintain or enhance the quality and acceptability of a food, the protein ingredients should possess certain functional properties that are compatible with the other ingredients and environmental conditions of the food system. Consequently, an important aspect of the development of new protein additives and their incorporation into food systems is the establishment of their functional properties. Functional properties of proteins are physicochemical properties through which they contribute to the characteristics of food. Study of functionality should provide information as to how a protein additive will perform in a food system (, A). These properties are... 

Environment. The physical and chemical environments have been shown to affect the functional performance of proteins. Factors, such as concentration, pH, temperature, ionic strength, and presence of other components, affect the balance between the forces underlying protein-protein and protein-solvent interactions (9). Most functional properties are determined by the balance between these forces. Although the comparison of discrete data from various studies might be of limited value, consideration of the response patterns of protein additives to changes in the environment of simple and/or food systems might be fruitful. 

Other workers (115-124 for example) have also centered their efforts on the role of phytic acid on zinc and iron bioavailabiliy from both soy and wheat products. It has been suggested (120) that the phytate-to-zinc molar ratio could be used to predict zinc bioavailability in high-phytate foods. Several groups (115, 117), including ours (113), 1 least partially supporT this hypothesis. However, recent work from our laboratory (112) involving soy protein of similar phytate-to-zinc molar ratios clearly demonstrates that zinc bioavailability is also altered by food processing. In this study, zinc from neutralized soy concentrates and isolates was shown to be less available to the rat than was the corresponding acid-precipitated products. This is unfortunate as alkaline conditions are commonly utilized for soy and other plant proteins to obtain beneficial functional properties. 

That is, we must learn how amino acid content and molecular configuration of food proteins are related to their functional properties. This goal is made more difficult by the fact that secondary, tertiary, and quarternary structures of proteins are likely to be quite different when exerting functional effects in food systems as compared to structures of the same proteins in dilute solutions and in their native states. The way in which specific actions of proteases affect protein structure must also be studied so that correlations with changes in functional properties can be made (61). 

Use of multiple regression techniques in the study of functional properties of food proteins is not new I76) Most food scientists have some familiarity with basic statistical concepts and some access to competent statistical advice. At least one good basic text on statistical modelling for biological scientists exists (7 ). A number of more advanced texts covering use of regression in modelling are available (, ). ... 

It is often best to begin with purified proteins when studying the relationships between protein structure and function at the molecular level. The presence of multiple proteins often complicates data interpretation, as it is not clear if effects are due to protein interactions, variations in the ratio of proteins, or to other factors. In these studies it is advisable to select tests based on a fundamental physical or chemical property, since results are less likely to vary with the test conditions or instrumentation used. Unfortunately, it becomes less likely that the property under study will relate directly to function in a food system when such simplified (often dilute) systems are used. Something as seemingly insignificant as protein concentration in the model system can have a large influence on the results obtained. Also, the relative importance or contribution of a functional property to a complex food system can be misinterpreted in a purified model system. 

The second type of study which has contributed to our understanding of the functional properties of oral chemoreceptor systems is human psychophysics, where verbal reports are taken on the taste properties of food and beverages and their chemical constituents. It is often possible for an individual to break a flavor complex down into a variety of distinguisable sensations. These sensations are end products of neural processing that are available to consciousness. Any natural food is of complex chemical composition and thus activates a wide variety of oral and nasal chemoreceptors. These flavor sensations may arise entirely from the oral cavity or require both oral and nasal stimulation. 

Primary structure of proteins can be chemically modified in order to improve their functional properties. This approach has been used with success to study the structure-function relationships (enzymatic function, biological function, physico-chemical and functional properties). Deliberate chemical modification of food proteins can result in alteration of the nutritive value, formation of potentially toxic amino acid derivatives, and contamination by toxic chemicals. 

One of the most important factors that determine whether or not a protein is usable in the fabrication of a food product is its functionality. The functionality results from a combination of physico-chemical properties that define the behavior of the food protein in food systems. It is evident that a detailed understanding of food protein functionality requires an intimate knowledge of the protein structure. The bovine milk protein system has been studied in great detail. Although providing useful structure-function... 

A whey protein hydrolysate BioZate , containing ACE-inhibitory peptide was recently developed by Davisco Foods International Inc. The effect on blood pressure was studied with 30 unmedicated, non-smoking, borderline hypertensive men and women, and daily dose was 20 g. The results indicated that there was a significant drop in both systolic and diastolic blood pressure after 1-week treatment, which persisted throughout the study of 6 weeks. The application of this product is varied and flexible. In addition to the bioactive peptides, it has functional properties such as emulsification and foaming (Klink, 2002). 

In particular, we have concentrated on developing techniques for isolating protein to attain this objective we have studied the practical use of chemical modification. The application of chemical modification to food proteins has been explored for several purposes to block deteriorative interactions between reactive groups (e.g., e-NH2 and reducing sugars) to improve functional properties (solubility, flavor, and thermal stability) to enhance nutritive value and digestibility to facilitate the elucidation of interrelationship between structure and functional properties (6,7,8,9) and, as discussed herein, to facilitate the preparation of protein isolates. 

There are large resources of potential food proteins (oilseed, yeast, leaf) which are presently unexploited. With the application of innovative scientific and technological methods these can become significant sources of food protein. In developing ingredient protein from plant sources, research emphasis must include studies to determine the physicochemical or functional properties of these proteins. 

Many workers have studied the influence of enzymatic hydrolysis on the functional properties of various food proteins, and much of this work has recently been reviewed by Richardson (2). However, there seem to be very few reports which quantitatively relate functionality to parameters which characterize the protein hydrolysates per se (e.g. molecular weight). Ricks et al. (3 ) examined the solubility and taste of a number of pure proteins (denatured pepsin, lactoblobulin, a-Sj -, K-, and 8-casein) hydrolysed with... 

In the food area, protein supplies are emphasized more frequently and are mostly studied for the nutritional properties. It should be pointed out, in the strongest terms, that protein foods are rarely used as crude powders or in their native forms. They are ingested most frequently as part of a complex food system where their functionality, rather than their nutrition, is the property most obvious to the consumer. In fact, many projects to alleviate protein malnutrition in less-developed countries have floundered because the introduced food forms did not fit the accepted pattern (i.e., the functionality) of the foods normally used in the region. Therefore, it is now commonly recognized, for improved nutritional standards, that any new food introduced into a population must, of necessity, be considered for its functional properties. Improving these properties will be a major factor in the successful adoption of the new food by the people in the area. Understanding the relation between protein structure and functionality is an important step in accomplishing these tasks. 

Sorption of various gases (02, N2, C02, and He) on wheat flour, soybean flour, potato starch, and wheat starch has been investigated in order to study the effect of those gases on the functional properties of processed food products. Results indicate that such properties improved only after flour and starch were treated with chlorine.455,456 The adsorptivity of various gases by starch has been reexamined.457 Liquid ammonia quickly forms a gelatinous paste with starch.458 Tomasik et al.459 attempted to prepare inclusion complexes of starch with colloidal sulfur. A key result was that inclusion inside the starch matrix was only possible in small amounts because of the large relative size of the sulfur micelles. 

For such starchy foods as noodles, cakes, pastries, processed potato food, and puddings, lipids improve the texture. The tendency of bread to staling is also related to the presence of lipids and emulsifiers. In order to satisfy market demands, it is important to optimize the water-binding capacity, the rate of water sorption, and the swelling power. The effects of lipids on these properties is under ongoing study. The mode of application of lipids is also a factor which controls functional properties.851-853 869 The effect of all these factors on bread quality has been recognized.870-873... 

Abugoch, L., Romero, N., Tapia, C., Silva, J., and Rivera, M. (2008). Study of some physicochemical and functional properties of quinoa (Chenopodium quinoa Willd.) protein isolates. ]. Agric. Food Chem. 56,4745 750. 

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