Chemical Modifications of Normal and Waxy Potato Starches Affect Functional Properties of Aerogels.

Aerogels are of increasing interest because of their exceptionally large surface area, porous structure, and low weight. Despite the significant increase in interest in the subject of starch-based aerogels, the number of detailed studies is rather scarce, which is especially evident in the case of chemically modified derivatives. Therefore, the study aims to evaluate the physicochemical properties of aerogels from chemically modified potato starch preparations (E 1422 and E 1450) obtained both from normal and waxy starches. Aerogels were prepared through the retrogradation of starch pastes followed by the gradual replacement of water with ethyl alcohol. The obtained preparations were characterized in terms of their bulk density, oil-binding capacity, as well as the texture and rheological properties of the formed pastes. Moreover, their usefulness was evaluated in an emulsion system employing rheological and low-field NMR methods. The obtained aerogels were characterized by a lower bulk density of 0.18-0.59 g/cm3 and 5.4-6.6 times higher oil-binding capacity compared to native potato starch. The chemical modification of starch helped to further alter the functional properties of the obtained aerogels, making them more effective oil binders, emulsifiers, and stabilizers (increasing the stability from 55 to 90%), which was especially evident for E 1450 preparation. Amylose content improved the aerogel properties, as waxy preparations were characterized by worse functional properties with the only exception of improved thickening ability. The most beneficial properties for the preparation of emulsions were observed for the aerogel obtained based on E 1450 normal potato starch.

Water Behavior of Aerogels Obtained from Chemically Modified Potato Starches during Hydration.

Aerogels are highly porous materials that are prepared by removing water held within a hydrogel in a manner that maintains the three-dimensional structure of the gel. Recently, there has been much interest in the preparation of aerogels from biopolymers, including starch. The applicability of native starches in the food industry is partially limited; therefore, the functional properties of starch are often improved by means of physical and/or chemical modification. The aim of the work was the analysis of molecular dynamics and the transport of water in aerogels obtained from native and chemically modified potato starches of the normal and waxy variety. Chemical modification with OSA (E 1450) as well as cross-linking with adipic anhydrite and acetylation (E 1422) had no significant impact on the hydration of potato starch aerogels as well as equilibrium water activity. The introduction of chemical moieties into starch macromolecules led to the improved binding of water by the biopolymer matrix; this was especially evident in the case of waxy starch derivatives. A increase in the amylopectin-to-amylose ratio of starch used for production of aerogels resulted in a decrease of equilibrium water activity along with spin-lattice relaxation time.

Water Behavior of Emulsions Stabilized by Modified Potato Starch.

Starch is a widely known and used emulsion stabilizer. In order to improve its properties, various types of modifications are made that change its ability to emulsify and stabilize. This paper describes the analysis of the molecular dynamics of water using low-field nuclear magnetic resonance (LF NMR) in oil-in-water emulsions obtained with the use of physically or chemically modified potato starch. The analysis of changes in spin-spin and spin-lattice relaxation times depending on the temperature allowed the activation energy value of water molecules in the analyzed emulsions to be determined. It has been shown that the presence of starch influences the values of spin-lattice T1 and spin-spin T2 relaxation times, both in the water and the oil phase, and the observed changes largely depended on the type of starch modification. Both types of analyzed starches also differently influenced the energy of activation of rotational movements of water molecules. On the basis of the analyses carried out with the use of LF NMR, it can be concluded that physically modified starch acts not only as a stabilizer, but also as an emulsifier, while acetylated starch does not exhibit good emulsifying properties.

Functionality of Native Starches in Food Systems: Cluster Analysis Grouping of Rheological Properties in Different Product Matrices.

Industrial application of starch as a texture-forming agent is primarily limited to preparations obtained from waxy corn and potatoes. The main reason behind this is its functionality, which depends mostly on rheological properties. However, in food product matrices, these properties change. Despite the vast amount of information on the rheological properties of various starches, the rational choice of thickener appears to be an extremely difficult task. The aim of the work is to systemize the information on the rheological properties of most popular starches in matrices of various food products, applying principal component and cluster analyses. The investigated material is potato and corn starch of the normal and waxy varieties. Binary mixtures containing salts or sweetening agents, as well as four different food products (ketchup, mayonnaise, pudding, and jelly), are investigated. It was found that compared to normal varieties, waxy starches reveal many similar rheological properties in all investigated models and food systems. Furthermore, in most applications, one waxy starch variety may be substituted by another, with no significant impact on the rheological properties and texture of the food product. Moreover, waxy starch preparations are less altered by the presence of cosolutes, i.e., salts and sugar alcohols. Starch model systems were proven to be useful only for rapid thickener screening tests and cannot be recommended as a final reference for the quality design of food products.

The Effect of Buckwheat Hull Extract on Lipid Oxidation in Frozen-Stored Meat Products.

This study investigated the effect of antioxidants on lipid stability of frozen-stored meat products. Buckwheat hull extract was used to enrich fried meatballs made from ground pork. During 180-d storage of meat products, lipid oxidation (peroxide and 2-thiobarbituric acid reactive substances [TBARS] value) was periodically monitored. The results were compared with butylated hydroxytoluene (BHT). The addition of antioxidants decreased lipid oxidation in stored meatballs. The highest ability to control peroxide and TBARS values was demonstrated for buckwheat hull extract. Moreover, buckwheat hull extract showed a higher 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity as well as higher Fe(II) ion chelating ability, as compared with BHT. The total content of phenolic compounds are highly correlated to the individual polyphenols in extract of buckwheat hull, among which the following were assayed: 3,4-dihydroxybenzoic acid, 4-hydroxybenzoic acid, gallic acid, isovanillic acid and p-coumaric acid, and flavonoids: isoorientin, quercetin, quercetin 3-d-glucoside, rutin, and vitexin. These results indicate that plant extracts can be used to prolong shelf life of products by protecting them against lipid oxidation and deterioration of their nutritional quality.

Molecular and Supermolecular Structure of Commercial Pyrodextrins.

Size exclusion chromatography with triple detection as well as infrared spectroscopy studies of commercially available pyrodextrins proved that these molecules are characterized not only by significantly lower molecular mass, in comparison to that of native starch, but also by increased branching. Therefore, pyrodextrins adopt a very compact structure in solution and show Newtonian behavior under shear in spite of their molecular masses of tens of thousands Daltons. The results also indicate that 50% reduction of digestibility of pyrodextrins is, to a minor extent, caused by formation of low-molecular color compounds containing carbonyl functional groups. The main reason is, as postulated in the literature, transglycosidation that leads to decreased occurrence of α-1,4-glycoside bonds in the molecular structure. In the process of dextrinization starch also undergoes changes in supermolecular structure, which, however, have no influence on digestibility. Likewise, the effect of formation of low-molecular colorful compounds containing carbonyl groups is not crucial.

Type IV resistant starch increases cecum short chain fatty acids level in rats.

Resistant starches are type of dietary fibers. However, their physiological effects depend on the way they resist digestion in the gastrointestinal tract. The objective of this study was to examine the hypothesis that new type of RS4 preparations, of in vitro digestibility of about 50%, obtained by cross-linking and acetylation, acts as a prebiotic by increasing short chain fatty acids content in cecum digesta. The rats were fed with diet containing pregelatinized, cross-linked and acetylated starches as a main carbohydrate source. Pregelatinized, but not chemically modified, potato starch was used in the composition of the control diet. After two weeks of experiment the increase of short chain fatty acids contents in ceceum digesta was observed. The intake of starch A, cross-linked only with adipic acid, resulted in increase of about 40% of short chain fatty acids content, whereas starch PA cross-linked with sodium trimetaphosphate and adipic acid of about 50%. The utmost twofold increase was observed in the case of the production of propionic acid. In contrast, the content of butyric acid increased (12%) only as an effect of consumption of starch PA and even decreased (about 30%) in case of starch A. Both RS4 starches caused an increase of the production of acetic acid by more than 40%. No changes in serum biochemistry, liver cholesterol and organ weights of rats were stated.

Sodium salt of starch octenylsuccinate as an emulsifier in "light" type mayonnaises.

INTRODUCTION: The E 1450 sodium salt of starch octenylsuccinate which exhibits emulsifying properties is used as food additive and is also recommended as yolk replacer in the process of mayonnaise production. Commercial E 1450 preparations reveal excellent functional properties in mayonnaise production. However, sodium salt of starch octenylsuccinate produced in the course of the suspension process (as well as the product of its hydrolysis in a membrane reactor), despite high surface activity, is unsuitable for this purpose. Therefore, a hypothesis was put forward that the cause of the unsuitability of these preparations for mayonnaise production is their improper profile of molecular mass distribution and the objective of this study was to verify the above thesis. MATERIAL AND METHODS: E 1450 preparations of different degree of substitution obtained alternately by means of reactive extrusion or enzymatic hydrolysis preceded by esterification in suspension were investigated. Preparations were characterised physico-chemically by determining the degree of substitution, viscosity, emulsifying activity index (EAI) and their capability to stabilise model emulsions (ME). Their molecular mass distribution profiles were determined and their suitability for the manufacture of low-fat mayonnaises was assessed. These investigations were also carried out for mixtures of preparations obtained as a result of a reactive extrusion and hydrolysis of the ester obtained during the suspension process. RESULTS: Despite the fact that the preparations obtained in suspension were characterised by 100% values of the ES parameter, all attempts to manufacture with their assistance of mayonnaise by way of a simple substitution in the formulation of dried egg yolk by E 1450 starch failed. Similarly, attempts to manufacture mayonnaise using any of the preparations obtained by means of reactive extrusion or enzymatic hydrolysis of the reaction product in suspension also ended in failure. The only successful solution was the application of equilibrium mixtures of E 1450 preparations obtained by way of reactive extrusion with a hydrolisate. Table 2 collates texture parameters of the obtained mayonnaises. CONCLUSION: The performed investigations fully corroborated the correctness of the proposed hypothesis that the suitability of the starch octenylsuccinate sodium salt as an emulsifier for low-fat mayonnaises is associated with the appropriately high polydispersity of this polymer.