Pasting Behavior and Viscoelastic Properties of Fresh, Chilled, and Rehydrated Freeze-Dried Gel Beads from Blends of Tapioca Flour, Soy Flour, and Cane Sugar

An extreme vertices design for a mixture of three components was used to establish the proportions of tapioca flour (50% to 100% w/w), soy flour (0% to 50% w/w), and cane sugar (0% to 10% w/w) mass fractions in a food gel bead system. Thus, nine compositions were prepared and analyzed. The pasting profiles of the mixtures were studied using a Rapid Visco Analyzer. The texture profiles of fresh, chilled, and rehydrated freeze-dried gel beads were studied using a texture analyzer. Increasing the proportion of soy flour in the range of 11.25% to 50.00% w/w decreased the peak viscosity, breakdown, final viscosity, and setback of mixed flour. Tapioca flour in the proportion of 81.25% to 100.00% w/w recorded the lowest hardness of fresh gel beads (92.00 to 283.00 g). Soy flour in the proportion of 11.25% to 50.00% w/w exhibited lower texture profiles (hardness, chewiness, and gumminess) than tapioca flour in gel beads for both chilled and rehydrated freeze-dried gel beads. Significant relationships were found among pasting profiles of the flour mixtures and texture profiles of fresh, chilled, and rehydrated freeze-dried gel beads, implying a functional role for soy flour in food gel beads. In conclusion, soy flour can act as an anti-retrogradation agent for the gel beads both in chilled (stored at 4°C for 7 days) and freeze-dried conditions. A small amount of cane sugar does not affect the inhibition of starch retrogradation in the gel bead system. Keywords: Anti-retrogradation, Food gel bead, Pasting profile, Soy flour, Tapioca flour, Texture profiles

Pasting and Rheological Properties of Different Starches Using Starch Cell of Discovery Hybrid Rheometer

The study was conducted to evaluate the pasting and rheological measurements of four different starches (wheat, rice, corn and chickpea) using starch pasting cell of the hybrid rheometer. The experiment was planned to initially record the pasting behavior of starches in the starch cell using heating, holding and cooling program. The cooked gels were then subjected to steady shear and dynamic rheological measurements in the same cell. The highest peak and the final and setback viscosities were recorded for chickpea starch while the lowest values were obtained for the rice starch. The pasting curves of different starches represented the typical curve as observed using the traditional visco-analyzer or visco-amylograph. All the studied starches represented shear-thinning non-Newtonian behavior (n was less than 1) when studied for their steady shear properties. The starches could be classified from less to more pseudoplastic as rice>corn>wheat>chickpea. The activation energy of rice starch was highest (142719 J/mol) while the activation energy of chickpea starch was lowest among all the starches (13291 J/mol). The storage moduli, loss moduli and tan ? were increased with increasing the frequency, and the crossover was also observed in corn, rice and wheat starch at the higher frequency. It is well evident from all the studied parameters that starch cell can be conveniently used to study the pasting and rheological properties of starches.

The Proportion of Fermented Milk in Dehydrated Fermented Milk–Parboiled Wheat Composites Significantly Affects Their Composition, Pasting Behaviour, and Flow Properties on Reconstitution

Dairy and cereal are frequently combined to create composite foods with enhanced nutritional benefits. Dehydrated fermented milk–wheat composites (FMWC) were prepared by blending fermented milk (FM) and parboiled wheat (W), incubating at 35 °C for 24 h, drying at 46 °C for 48 h, and milling to 1 mm. Increasing the weight ratio of FM to W from 1.5 to 4.0 resulted in reductions in total solids (from 96 to 92%) and starch (from 52 to 39%), and increases in protein (15.2–18.9%), fat (3.7–5.9%), lactose (6.4–11.4%), and lactic acid (2.7–4.2%). FMWC need to be reconstituted prior to consumption. The water-holding capacity, pasting viscosity, and setback viscosity of the reconstituted FMWC (16.7% total solids) decreased with the ratio of FM to W. The reconstituted FMWC exhibited pseudoplastic flow behaviour on shearing from 18 to 120 s−1. Increasing the FM:W ratio coincided with a lower yield stress, consistency index, and viscosity at 120 s−1. The results demonstrate the critical impact of the FM:W ratio on the composition, pasting behavior, and consistency of the reconstituted FMWC. The difference in consistency associated with varying the FM:W ratio is likely to impact on satiety and nutrient value of the FMWCs.