Substitution of modified starch with hydrogen peroxide-modified rice bran in salad dressing formulation: physicochemical, texture, rheological and sensory properties

Effect of Inulin on Rheological Properties and Emulsion Stability of a Reduced-Fat Salad Dressing

This study is aimed at investigating the potential use of inulin in a reduced-fat salad dressing to improve its rheological properties, fat globule size distribution, and emulsion stability. The reduced-fat salad dressing, which has 50% less fat compared to the full-fat counterpart (control), was prepared with varying inulin concentrations (10, 12.5, 15, 17.5, and 20% w/w). The full-fat and reduced-fat salad dressings exhibited a non-Newtonian shear-thinning behavior. Power law model was used to describe the rheological properties. Results showed that the flow behavior index (n) and consistency coefficient (K) were greatly affected by the concentration of inulin. A greater pseudoplasticity and apparent viscosity of the reduced-fat samples were achieved with a higher concentration of inulin. Oscillatory tests showed that the storage modulus (G') and loss modulus (G ″) values increased with increasing inulin concentration. All samples displayed characteristics of a viscoelastic solid, as evidenced by a greater G' than G ″. Regarding the size distribution of the oil droplets, the reduced-fat salad dressing containing a higher inulin content was observed to have a larger droplet size. All reduced-fat samples, similar to the full-fat counterparts, exhibited stability with no cream separation over one month of storage at 4°C, as determined by visual observation. Additionally, the reduced-fat salad dressings supplemented with 17.5 and 20% inulin exhibited stability against cream separation, comparable to the full-fat counterpart (p > 0.05), as measured by the thermal stress test (80°C for 30 min) with centrifugation. The sensory acceptance scores for reduced-fat salad dressing with 15 and 17.5% inulin, ranging from approximately 6.28 to 7.63 on a 9-point hedonic scale for all evaluated attributes (appearance, color, aroma, texture, taste, and overall acceptability), were not significantly different from those of the full-fat counterpart (p > 0.05). This study demonstrated that inulin may be a suitable ingredient in reduced-fat salad dressings.

Effects of insoluble dietary fiber and ferulic acid on rheological and thermal properties of rice starch

This study aimed to evaluate the effects of insoluble dietary fiber (IDF) and ferulic acid (FA) on the properties of rice starch (RS), including gelatinization, thermodynamic, rheological parameters, and freeze-thaw stability. Rapid viscosity analysis (RVA), differential scanning calorimetry (DSC), rheological analysis, and freeze-thaw stability analysis were performed. The results showed that the presence of IDF and FA could significantly delay the short-term retrogradation of RS, especially at high FA concentrations. Rheological tests showed that IDF was not conducive for the elasticity, viscosity enhancement, and system stability of the starch gels. However, FA could offset the deterioration of the system caused by IDF and further improve the gel properties. The presence of IDF and FA weakened the freeze-thaw stability of the starch gel, unlike their single action on the starch gel, correspondingly. The results show that FA could alleviate the degradation of RS gel performance caused by IDF in the ternary system. The findings provide potential possibilities for improvements in the quality of rice starch gel-based products.

Structural and physicochemical characterization of modified starch from arrowhead tuber (Sagittaria sagittifolia L.) using tri-frequency power ultrasound

Sagittaria sagittifolia L. is a well-known plant, belongs to the Alismataceae family. Sonication can improve the functional properties of starch; hence, the aim of this study was to develop ultrasonically modified arrowhead starch (UMAS) using a sophisticated and eco-friendly tri-frequency power ultrasound (20/40/60 kHz) method at 300, 600, and 900 W for 15 and 30 min. Significant (p < 0.05) increases in swelling power, solubility, and water and oil holding capacities were achieved. FTIR spectroscopy corroborated the ordered, amorphous, and hydrated crystals of the sonicated samples. Increases in sonication frequency and power led to significant (p < 0.05) increases in onset gelatinization temperatures. Scanning electron microscopic analysis of sonicated samples showed superficial cracks and roughness on starch granules appeared in a sonication power-dependent manner compared with that of untreated sample. Overall, the ultrasonically-treated samples showed improved physicochemical properties, which could be useful for industrial applications.

Alkaline hydrogen peroxide improves physical, chemical, and techno-functional properties of okara

The objective was to evaluate the effect of modifying okara with alkaline hydrogen peroxide at different H2O2 concentrations and treatment temperatures on its soluble fiber content, water absorption and holding capacity, swelling capacity, and protein solubility in water. Multi-response optimization and characterization of physical, chemical, and techno-functional properties of unmodified and modified okara under optimal condition were performed. Treatment under optimal condition (2% H2O2 and 42 °C for 5 h) resulted in a 601% increase in soluble fiber content, a 26% increase in water absorption and holding capacity and swelling capacity, and a 609% increase in soluble protein. Scanning electron micrographs revealed that modified okara particles had a more fragmented structure and a rougher surface than control. Alkaline hydrogen peroxide treatment altered the color, chemical composition, and techno-functional properties of okara. The modification method has potential to add value to okara and contribute to the use of agro-industrial residues.

Faba bean protein in reduced fat/cholesterol mayonnaise: extraction and physico-chemical modification process

Effect of faba bean enzymatic protein extraction process parameters were investigated at different ultrasound powers (200, 300 and 400 W), sonication times (15, 25 and 35 min), enzyme dosages (0.15, 0.3 and 0.45%) and enzyme treatment times (15, 25 and 35 min). Physico-functional characterization of the protein samples through solubility, zeta potential, color, fat adsorption, emulsifying and foaming capacity measurements suggested faba protein as a promising substituent to egg yolk powder in reduced fat mayonnaise formulation. Reduced-fat mayonnaise formulation containing different faba protein/egg yolk powder ratios were prepared and characterized through rheological analyses as well as emulsion stability, texture, color and microstructural evaluations. The formulations containing equal compositions of faba bean protein and egg yolk powder (0.375%) and also the one with 0.5% faba bean protein and 0.25% egg yolk powder were finally suggested to substitute the conventional formulation.

Synergistic interactions between konjac-mannan and xanthan/tragacanth gums in tomato ketchup: Physical, rheological, and textural properties

In this research, simultaneous contribution of konjac-mannan (0.3%), xanthan (0.3%), and tragacanth (0.3%) gums in tomato ketchup was investigated comparing the physicochemical, rheological, texture, and sensory properties with the control sample containing 0.3% xanthan gum. Samples selected through viscosity and syneresis evaluation of the nine prepared samples were analyzed by color, flow behavior, frequency sweep, particle size, texture, and sensory experiments. Results indicated that increasing xanthan concentration did not have any significant effect on the apparent viscosity while considerable improvement was observed in the physical stability of ketchups containing konjac-mannan/xanthan ascribed to smaller particles with larger contact surfaces encouraging gel network formation. Highest a* and a*/b* was observed for konjac-mannan/xanthan (0.075%/0.225%) in which formation of hydrated gel granules of gums intensifies light diffraction due to the decreased particle size. This synergistically formed viscous three-dimensional gel network is responsible for the highest cohesiveness and gumminess of the same sample between the ketchup formulations containing two gums. Organoleptic properties of ketchup samples containing konjac-mannan/xanthan showed no significant difference with the control sample. PRACTICAL APPLICATIONS: Development of modern food technologies along with the lifestyle changes over the past few decades and grown public awareness of the relevance between health and nutrition have considerably increased the consumption of ready meals containing low-fat and fiber-rich functional condiments. Ketchup is a popular sauce thickened with tomato pulp powder, potato or corn starch, modified starch, and severally available hydrocolloids such as carboxymethyl cellulose, xanthan, guar, and locust bean gum. In this research work, mixtures of konjac-mannan and xanthan/tragacanth hydrocolloids are used to produce new ketchups with improved physical and rheological properties and lower prices.