Applications In Food Formulations Research Articles

Conformational and thermal properties of phaseolin, the major storage protein of red kidney bean (Phaseolus vulgaris L.)

A previous study of various functional and physicochemical properties of phaseolin indicated good potential of phaseolin for application in food formulations in view of its excellent functional properties. The aim of the present study was to explore the conformational and thermal properties of phaseolin in the presence of protein structural perturbants by intrinsic fluorescence emission spectroscopy and differential scanning calorimetry. Raman spectroscopy was also used to characterise the secondary structures of phaseolin. The Raman spectrum of phaseolin indicated that β-sheets and random coils were the major secondary structures. Intrinsic fluorescence emission spectroscopy confirmed the structural peculiarity and compactness of phaseolin, as evidenced by the absence of any shift in emission maximum (λ(max)) in the presence of structural perturbants such as sodium dodecyl sulfate (SDS), guanidine hydrochloride, urea and dithiothreitol (DTT). Increasing NaCl concentration enhanced the thermal stability of phaseolin. Addition of chaotropic salts (1 mol L(-1)) caused progressive decreases in thermal stability following the lyotropic series of anions. Decreases in thermal denaturation temperature (T(d)) and enthalpy change (ΔH) were observed in the presence of protein perturbants such as SDS, urea and ethylene glycol, indicating partial denaturation and a decrease in thermal stability. DTT and N-ethylmaleimide had little effect on the thermal properties of phaseolin, confirming that phaseolin, a 7S globulin, is devoid of inter-polypeptide disulfide bonds. The data presented here demonstrate the contributions of hydrophobic and electrostatic interactions and hydrogen bonding to the conformational stability of phaseolin.

OPTIMIZATION OF ENZYMATIC SYNTHESIS OF ISOMALTO-OLIGOSACCHARIDES PRODUCTION

Glucosyltransferases can be applied in the synthesis of prebiotic oligosaccharides. Enzymatic synthesis using acceptors can be used to obtain these carbohydrates. When maltose is the acceptor, oligosaccharides containing one maltose moiety and up to eight glucose units linked by α-1,6-glycosidic bonds are obtained as the product of dextransucrase acceptor reaction. In this work, the enzymatic synthesis of isomalto-oligosaccharides using dextransucrase from Leuconostoc mesenteroides NRRL B-512F was optimized by response surface methodology. The effect of maltose and sucrose concentrations on the acceptor reaction was evaluated in a batch reactor system. Partially purified enzyme was used to reduce the enzyme purification cost. The results showed that high sucrose concentrations in conjunction with high maltose levels enhanced the isomalto-oligosaccharide synthesis. A productivity of 42.95 mmol/L.h of isomalto-oligosaccharides was obtained at the optimal operating condition (100 mmol/L of sucrose and 200 mmol/L of maltose). PRATICAL APPLICATIONS Oligosaccharides as prebiotic have a large application in food formulations, and their beneficial role in human health have been extensively studied. Although the acceptor mechanism of dextransucrase has already been extensively studied, an industrial process has not been developed yet for enzyme synthesis of isomalto-oligosaccharide. The process studied in this work allows the large-scale preparation of isomalto-oligosaccharide using partially purified enzyme.

Gelling properties of kefiran, a food-grade polysaccharide obtained from kefir grain

The physicochemical and gelling properties of kefiran, a water-soluble glucogalactan with probed health-promoting properties, were investigated. Gel permeation chromatograms revealed a single distribution of molecular weight corresponding to 10 7 Da. Intrinsic viscosity of kefiran determined using Huggins extrapolations was 6.0 dl/g and using Kramer approximations was 5.95 dl/g. Kefiran has a Newtonian behaviour in diluted solutions, which becomes pseudoplastic at higher concentrations. Rheological behaviour of the solution before and after freeze drying was evaluated by small deformation oscillatory rheological measurements. The mechanical spectrum of solution corresponded to an entangled network behaviour. After freeze–thaw treatment of the solution, a rheological behaviour transition from a liquid-like system to a gel was observed. The storage modulus ( G′) in cryogels was 35 times higher than the value obtained for the solution. Rheological characteristics of the cryogel were influenced by kefiran concentration. As the polymer concentration increased, higher number of interactions was evident for the increment in both moduli ( G′ and G″). The behaviour of kefiran cryogels about 37 °C determines its ability to melt at mouth temperature. These results suggest that kefiran cryogels could be an interesting alternative for its application in food formulations.

Recent trends in the microbial production, analysis and application of Fructooligosaccharides

This review focuses on the recent developments in the area of FOS research—its microbial production, functional properties and applications and an overview of the different analytical methods for the determination of the FTase. Different microbial sources of FTase reported in literature to produce FOS with different linkages to form 1-kestose, 6-kestose and neokestose in varying yields based on initial sucrose concentration is discussed. Different fermentative methods have been used for production of FOS. SSF has been used for the production of a value added product FOS utilizing various agroindustrial byproducts. The nutritional and culture parameters when optimized, the FOS yields and productivity could be improved. The use of immobilized enzymes and cells has led to the development of effective and economic methods for large-scale production of FOS. Forced flow Membrane reactor systems, biocatalyst system with a bioreactor equipped with a microfiltration systems, have been used for production of high content FOS by removing the released glucose and unreacted sucrose from the reaction mixture resulting in up to 98% FOS. The use of mixed enzyme system of Fructosyl Transferase and glucose oxidase or glucose dehydrogenase, could produce highly concentrated FOS up to 90–98%. Nano-filtration for removing glucose resulted in FOS of 90% concentration. The purified enzyme was found to produce kestose and nystose unlike the crude enzyme which produced GF5 and GF6 oligosaccharides Kinetic parameters (Vm, Km, and Ki) of the enzyme were determined from experimental data on the transfructosylation rate at various substrate concentrations with and without addition of glucose Techniques like HPLC, using polar-bonded phase and resin-based HPLC columns are commonly used for separation of oligosaccharides with refractive Index Detector or pulsed amperometric detector and annular size exclusion chromatography for large scale and continuous fractionation. Other techniques like gas liquid chromatography, thin layer chromatography, NMR and Mass Spectrometry have been used for structure analyses. The functional properties like use as prebiotics, dietary fiber, role in absorption and defense/Immunity, lipid metabolism control of diabetics have been discussed. A variety of applications in food formulations are also discussed.

Use of high-performance size exclusion chromatography to characterize protein aggregation in commercial whey protein concentrates

Protein aggregation profiles of seven commercial whey protein concentrates (WPCs) with protein contents ranging from 32% to 81% were investigated by high-performance size-exclusion chromatography (HPSEC). Two protein fractions were identified: the aggregated protein fraction (APF) and the native protein fraction (NPF). Important differences were found in the proportions of APF ranging from 10% to 29% of the total protein. Centrifugation at 48,000×g for 45 min at 25 °C achieved nearly complete separation of the two fractions for all samples based on HPSEC analysis of both the supernatant and pellet. NPF was shown to contain multiple peaks separable by HPSEC. Electrophoresis (native-PAGE, reducing SDS-PAGE and non-reducing SDS-PAGE) demonstrated that aggregates were bound together by covalent and non-covalent bonds. This study shows that HPSEC provides a quantitative measurement of WPC protein aggregation, which is a useful parameter to be determined prior to WPCs application in food formulations.

Functional Properties of Chitin and Chitosan

ABSTRACTChitin (poly‐β (1⇒4)‐N‐acetyl‐D‐glucosamine), chitosan (deacetylated chitin) and microcrystalline chitin (redispersible chitin powder) were compared with microcrystalline cellulose to examine the use of those cellulose‐like biopolymers as functional additives for potential application in food formulations. Water binding, fat binding and emulsifying properties were studied. Baking tests were performed with 0.5–2.0% (flour basis) of microcrystalline chitin added to wheat flour bread or to potato protein fortified (8% potato protein concentrate) white bread. Water‐binding capacity and fat binding capacity of chitin, chitosan and microcrystalline chitin ranged from 230–440s (w/w) and from 170–315% (w/w). Chitosan and chitin did not produce emulsions but microcrystalline chitin showed good emulsifying properties and was superior to microcrystalline cellulose. Increasing concentration of microcrystalline chitin (0.12–0.8 g/100 ml water) had a positive effect on emulsion stability. Addition of microcrystalline chitin increased specific loaf volume of white bread and protein fortified breads. Water addition of 65% (flour basis) was found to be optimum for “chitin breads.”