Cross-linking, carboxymethylation and hydroxypropylation treatment to sorghum dietary fiber: Effect on physicochemical, micro structural and thermal properties.

The effect of cross-linking (CL), carboxymethylation (CM), and hydroxypropylation (HP) on the physicochemical, micro-structural, and thermal properties of sorghum dietary fiber (SODF) was studied. Results reflected that all three modifications significantly (p < 0.05) increased the water absorption capacity, swelling capacity, oil absorption capacity, and soluble dietary fiber content of SODF with CM being the most effective treatment. The CM significantly (p < 0.05) improved the solubility (9.9 %), whereas CL (4.65 %) and HP (2.79 %) significantly reduced the solubility of native SODF. The color analysis reflected the decrease in L* value after all modifications, indicating an increase in brown color of SODF. XRD analysis reflected an increase in crystallinity value (14.47 to 17.94 %) of SODF after modifications, resulting in increased thermal stability of modified SODF. The DSC results revealed the increased decomposition temperature of cross-linked and hydroxypropylated dietary fiber showing improved thermal stability of these types of modified fibers. The changes in thermal, physicochemical, and microstructural properties of SODF after modification could be ascribed to the changes in structure and chemical composition as reflected from SEM, XRD, and FTIR analysis.

Effect of nano-conversion on morphological, rheological and thermal properties of barley starch.

The aim of the present study was to synthesize biodegradable starch nanoparticles (SNP's) from a renewable source like barley starch and to characterize for morphological, crystalline, thermal, and rheological properties. Acid hydrolysis transformed A+V-type round or disc-shaped native starch (NS) granules with an average width of 10 µm and the average length of 22 µm into round or irregular shaped A-type SNP's with an average size of 64 nm with the crystallinity enhanced from 41.75 to 48.08%. The zeta potential of NS and SNP's was - 17.7 and - 21.4 nm, respectively, with the higher stability of SNP's. The gelatinization temperature increased while melting decreased after nano conversion of barley starch. The storage and loss moduli of 12 and 15% suspension of SNP's remained unchanged with a change in angular frequency (0.1-10 rad-s), which indicated a greater tendency to recover after deformation, while 20% SNP's suspension behaved like a viscous fluid. The flow behavior test demonstrated a shear-thinning behavior of SNP's suspension.

Barley ß-glucan concentrate and its acid hydrolysate for the modification of dough making and rheological properties of water chestnut flour.

ß-Glucans are known for their beneficial physiological roles but can be used as potential food hydrocolloid. The present study was performed to assess the potential of barley ß-glucan concentrates (native and partially hydrolyzed) in altering the functional properties of water chestnut flour dough. The ß-glucan concentrate was subjected to partial hydrolysis to prepare a low molecular weight polymer. The WAC, swelling behavior, and pasting properties were significantly modified after the addition of ß-glucan concentrates. The water chestnut dough incorporated with ß-glucan concentrates displayed enhanced viscoelastic and creep characteristics and the efficacy of ß-glucans in providing strength to water chestnut dough depended on its molecular weight. Hydrolyzed ß-glucan concentrates increased the elasticity of dough to the greater magnitude in comparison to its native counterpart.

Pasting, rheological, and dough mixing behavior of rice flour as affected by the addition of native and partially hydrolyzed ß-glucan concentrate.

This study was aimed at evaluating the potential of barley ß-glucan concentrates (native and partially hydrolyzed) in modifying the techno-functionality of rice flour dough. ß-Glucan concentrate was partially hydrolyzed to obtain a low molecular weight polymer and their influence on the pasting, rheological, and thermal properties of rice dough were assessed. Hydration, thermal, and pasting properties were significantly modified with the added ß-glucans. The rice dough supplemented with ß-glucan concentrates showed improved viscoelastic and creep behavior and the effectiveness of ß-glucans in imparting strength to rice dough depended on its molecular weight. Hydrolyzed ß-glucan concentrates having low molecular weight increased dough elasticity to the greater extent in comparison to native ß-glucan concentrates. The micrographs of supplemented dough showed a strong and dense network indicating improved structure and strength.

Synthesis and modification approaches for starch nanoparticles for their emerging food industrial applications: A review.

There is an emerging interest in the development of biomaterial-based nanoparticles. Recent studies have shown that starch nanoparticles (SNP's) could be prepared from starch granules with unique functional properties. Starch nanoparticles/nanocrystals can be prepared by acid or enzymatic hydrolysis, regeneration, mechanical treatments, and combined enzymatic and precipitation methods. Different approaches including chemical, physical, and enzymatic methods have been used to modify the SNP's to enhance and diversify their applications profile. SNP's have found novel applications in various food systems such as reinforcement materials in nanocomposites, encapsulating agents, emulsion stabilisers, and carrier and releasing agents.

Pectin and its acid hydrolysate for the modification of hydration, pasting, thermal and rheological properties of barley starch.

The influence of native pectin (NP) and its hydrolysate (PH) in modifying hydration, thermal, pasting, rheological and textural properties of barley starch was assessed. The addition of NP and PH significantly modified the hydration properties of barley starch. The swelling and solubility of barley starch increased in the presence of NP while PH decreased it in a concentration dependent manner. The differential scanning calorimetry results showed that gelatinization temperatures increased in the presence of NP/PH whereas decrease in enthalpy was observed. In addition, only NP was found effective in increasing peak viscosity of the barley starch during pasting while PH decreased it. PH was observed to be more efficient in terms of reducing setback and final viscosity. Moreover, the NP addition caused an increase in magnitude of G' and G" while lower values were obtained with PH suggesting an increase in the elasticity of barley starch pastes with NP and an increased viscous behavior in case of PH. This was further confirmed by scanning electron microscopy which revealed interconnected flakes network in starch pastes containing NP. Overall these results revealed that molecular weight and concentration of pectin played an important role in modifying starch functional properties.

Pasting, rheological, thermal and gel textural properties of pearl millet starch as modified by guar gum and its acid hydrolysate.

The influence of guar gum and its hydrolysate at different concentrations (1 and 2% w/w) on physicochemical, pasting, thermal, rheological and textural properties of pearl millet starch was assessed. The addition of guar gum and its hydrolysate significantly improved the hydration properties of pearl millet starch. NGG significantly (p < 0.05) increased the peak, breakdown, and final viscosities while GGH did not modify the peak and final viscosities but decreased breakdown viscosity. The molecular weight of guar gum had a predominating role in modifying the functional properties of pearl millet starch. Steady shear measurements showed that both NGG and GGH decreased the flow behavior index (n) increased and consistency index (K). Higher G' and G″ values were obtained after the addition of NGG and GGH, suggesting the formation of more solid like pastes.

Antioxidant activity of various extracts of selected gourd vegetables.

Study was conducted to evaluate the antioxidative activity of methanolic (ME), ethanolic (EE) and butanolic extracts (BE) of selected gourd vegetables. The antioxidant activity was investigated using different assays namely ferric thiocyanate test (FTC), thiobarbituric acid test (TBA), ferric reducing antioxidant power (FRAP) and DPPH free radicals scavenging test. A densitometric HPTLC analysis was performed for the analysis of phenolic acids and flavonoids. Different extracts of the selected gourd vegetables revealed different antioxidant activity. Different extracts of Lagenaria siceraria, Momordica charantia and Luffa cylindrica revealed significantly higher (p < 0.05) concentrations of total phenols, flavonids, tannins and carotenoids content and also the antioxidant activity in comparison to remaining vegetable extracts. Correlation studies indicated that FRAP test best described the antioxidant activity of phenols, flavonoids and carotenoids (r = 0.854, 0.692 and 0.915 respectively). HPTLC profiles revealed the presence of maximum number of phenolic acids and flavonoids in L. siceraria and M. charantia.

Effect of incorporation of plantain and chickpea flours on the quality characteristics of biscuits.

Blends of plantain and chickpea flours each with concentrations of 0, 10, 20, 30 and 40% along with of refined wheat flour were used for development of biscuits. The flours were evaluated for their chemical and functional properties. Plantain flour had highest crude fiber (3.6%) and carbohydrate content (80.8%), whereas chickpea flour had highest protein content (19.3%) and fat content (4.4%). Plantain flour showed highest water absorption (167.7%) whereas lowest oil absorption capacity (144.6). The chickpea flour showed highest foaming capacity and stability. The thickness and diameter of biscuits did not differ significantly (p < 0.05). The spread ratio and percent spread decreased with the addition of plantain and chickpea flours each up to a concentration of 30%. The fracture strength of biscuits increased significantly (p < 0.05) with addition of plantain and chickpea flours and was highest at 40% concentration (21.1 N). The protein and crude fiber content of biscuits increased significantly (p < 0.05) from 7.1 to 9.2% and 1.1 to 3.6%, respectively with increasing extent of chickpea flour and plantain flours in the blends. The sensory properties of biscuits prepared by replacing refined wheat flour up to 20% each with plantain and chickpea flour were more or less similar to those of control biscuits.

Optimization of osmotic dehydration conditions of peach slices in sucrose solution using response surface methodology.

Osmotic dehydration (OD) conditions of peach slices were optimized using response surface methodology (RSM) with respect to sucrose concentration (50-70°B), immersion time (2-4 h) and process temperature (35-55 °C) for maximum water loss (WL), minimum solute gain (SG) and maximum rehydration ratio (RR) as response variables. A central composite rotatable design (CCRD) was used as experimental design. The models developed for all responses were significant. All model terms were significant in WL except the quadratic levels of sucrose concentration and temperature whereas in SG, linear terms of time and linear and quadratic terms of temperature were significant. All the terms except linear term of time and interaction term of time and sucrose concentration, were significant in RR. The optimized conditions were sucrose concentration = 69.9°B, time = 3.97 h and temperature = 37.63 °C in order to obtain WL of 28.42 (g/100 g of fresh weight), SG of 8.39 (g/100 g of fresh weight) and RR of 3.38.

Studies on effect of multiple heating/cooling cycles on the resistant starch formation in cereals, legumes and tubers.

'Resistant starch' (RS) is defined as starch and starch degradation products that resist the action of amylolytic enzymes. The effect of multiple heating/cooling treatments on the RS content of legumes, cereals and tubers was studied. The mean RS contents of the freshly cooked legumes, cereals and tubers (4.18%, 1.86% and 1.51% dry matter basis, respectively) increased to 8.16%, 3.25% and 2.51%, respectively, after three heating/cooling cycles (P< or =0.05) with a maximum increase of 114.8% in pea and a minimum of 62.1% in sweet potato (P< or =0.05). Significant positive correlations were observed between the RS content and amylose (y=0.443x-5.993, r=0.829, P< or =0.05, n=9) as well as between the percentage increase in RS and insoluble dietary fiber content (y=2.149x-24.787, r=0.962, P< or =0.05, n=9). A differential scanning calorimeter study showed an increase in the T(0), T(p), T(c) and DeltaH values of the repeatedly autoclaved/cooled starches. The intact granular structure was also observed disappear, as studied using scanning electron microscopy.