Influence of corn starch type in the rheological properties of a white sauce after heating and freezing

Physical, sensory, and simulated mastication properties of texture-modified Spanish sauce using different texturing agents

This study aims to evaluate the colour texture, flow, viscoelastic, sensory, and simulated mastication properties, in the presence and absence of artificial saliva, of texture-modified Spanish sauce at different temperatures (25 °C, 37 °C and/or 55 °C). Sauce texture was modified using five hydrocolloids (modified starch (MS), guar gum (GG), tara gum (TG), sodium carboxymethylcellulose (CMC), and chia seed mucilage (CSM) as an alternative texturing agent), achieving two well-differentiated consistencies: honey-like and pudding-like. The MS, GG, TG and CSM sauces showed greater consistency, firmness, stiffness, and resistance to flow than the CMC samples. Furthermore, the internal structure of CMC sauces was the most affected by temperature changes. The addition of saliva decreased the apparent viscosity, consistency, and adhesiveness of the sauces. Among the samples studied, the GG and CSM texture-modified sauces would be suitable for dysphagic patients because of their good elasticity, relatively high resistance to deformation and structural stability, as well as better resistance to salivary α-amylase action. However, CSM sauces obtained the lowest sensory attribute scores. This work opens the door to the use of CSM as a texturing agent and demonstrates the importance of considering not only the hydrocolloid type and consistency level, but also the administration temperature of dysphagia-oriented products. Selecting a suitable texturing agent is of great importance for safe and easy swallowing by dysphagic patients.

Impact of thermo-sonication on quality indices of starch-based sauces

In this study, ultrasonication, a physical, relatively cheap, and environmentally benign technology, was investigated to characterize its effect on functional properties of rice starch and rice starch-based sauces. Temperature-assisted ultrasound treatment improved the granular swelling power, fat and water absorption capacities, and thermal properties of rice starch, signifying its suitability in the formulation of starch-based sauces. Rheological characterization of the formulated sauces revealed a shear-thinning flow behavior, well described by the Ostwald de Waele model, while viscoelastic properties showed the existence of a weak gel. Results indicated that ultrasonication significantly enhanced the pseudoplastic behavior of starch-based sauces. Additionally, textural analysis showed that textural attributes (stickiness, stringiness, and work of adhesion) were also improved with ultrasonication. Moreover, enhanced freeze/thaw stability was also achieved with ultrasound-treated starch-based sauces. Overall, the results from this study show that ultrasound-treated starches can be used in the formulation of sauces and potentially other food products, which meets the requirements for clean label and minimally processed foods.

Late-Maturity Alpha-Amylase in Wheat (Triticum aestivum) and Its Impact on Fresh White Sauce Qualities

When wheat experiences a cold-temperature ‘shock’ during the late stage of grain filling, it triggers the abnormal synthesis of late-maturity α-amylase (LMA). This increases the enzyme content in affected grain, which can lead to a drastic reduction in falling number (FN). By commercial standards, a low FN is taken as an indication of inferior quality, deemed unsuitable for end-product usage. Hence, LMA-affected grains are either rejected or downgraded to feed grade at the grain receiving point. However, previous studies have found no substantial correlation between low FN-LMA and bread quality. The present study extends previous investigations to semi-solid food, evaluating the physical quality of fresh white sauce processed from LMA-affected flour. Results show that high-LMA flours had low FNs and exhibited poor pasting characteristics. However, gelation occurred in the presence of other components during fresh white sauce processing. This demonstrates that LMA-affected flours may have new applications in low-viscosity products.

Physicochemical, pasting, and rheological properties of pearl millet starches from different cultivars and their relations

Physicochemical, pasting, and rheological properties of pearl millet starches were studied and correlations among these properties were calculated. Amylose content, swelling power, and solubility of starches varied from 11.57 to 21.93%, 11.11 to 17.91 g g−1 and 12.20 to 15.20%, respectively. Volume% of starch granule size less than 10 µm varied from 36.23 to 48.34%, and 12.16 to 18.75% for above 20 µm size of granule. Peak viscosity of starches varied from 1291 to 1853 mPa·s, cv. RHB-173 had the highest value. Frequency sweep measurement of starch pastes revealed higher magnitude of G′ as compared to G″ with increase in to, indicating visco-elastic behaviour. Yield stress (σo), consistency index (K), and flow behaviour index (n) were observed as 40.73 to 115.72 Pa, 0.729 to 3.998 Pa·s, and 0.604 to 0.964, respectively. Starch pastes from cultivars studied showed shear thinning behaviour.

Influence of Fiber Addition on White Sauces Made with Corn Starch: Effect on Their Freezing/Thawing Stability

Fiber-enriched white sauces with apple (AF401), potato (KF200), and microcrystalline cellulose (MCC) were selected among six white sauces, all of them elaborated by replacing corn starch and milk with 3% of different dietary fibers. It was investigated the freezing/thawing (F/T) stability of these three enriched white sauces studying their physico-chemical (color, syneresis percentage, total soluble solids content), rheological (viscoelastic and steady measurements), and sensorial properties before and after a freezing/thawing treatment. White sauce with MCC resulted in being the most like the control (without fiber) showing a higher elasticity and a heat stability. Moreover, the sauce elaborated with MCC has a sensorial profile as a traditional corn starch sauce with high "creaminess" and lower "heterogeneity" after the F/T treatment. Therefore, the properties provided by MCC make this product interesting in food design, and MCC sauce could be used as an industrial frozen fiber-enriched white sauce. PRACTICAL APPLICATION: These days, there is an increase in the demand of precooked frozen dishes due to current lifestyles and because the use of fiber exhibits many proven health benefits. A béchamel sauce made from corn starch and enriched with different fibers was elaborated, frozen and thawed in microwave. Both fresh and frozen/thawed microcrystalline cellulose (MCC) sauces exhibited very similar rheological and sensorial properties to an industrial and traditional frozen white sauce without fiber. Therefore, MCC-enriched white sauce resulted to be a feasible strategy to produce a white sauce suitable for frozen dishes with good functional properties and sensorial quality.

Effects of Pressure, Temperature, Treatment Time, and Storage on Rheological, Textural, and Structural Properties of Heat-Induced Chickpea Gels

Pressure-induced gelatinization of chickpea flour (CF) was studied in combination with subsequent temperature-induced gelatinization. CF slurries (with 1:5 flour-to-water ratio) and CF in powder form were treated with high hydrostatic pressure (HHP), temperature (T), and treatment time (t) at three levels (200, 400, 600 MPa; 10, 25, 50 °C; 5, 15, 25 min). In order to investigate the effect of storage (S), half of the HHP-treated CF slurries were immediately analyzed for changes in oscillatory rheological properties under isothermal heating at 75 °C for 15 min followed by cooling to 25 °C. The other half of the HHP-treated CF slurries were refrigerated (at 4 °C) for one week and subsequently analyzed for changes in oscillatory properties under the same heating conditions as the unrefrigerated samples. HHP-treated CF in powder form was analyzed for changes in textural properties of heat-induced CF gels under isothermal heating at 90 °C for 5 min and subsequent cooling to 25 °C. Structural changes during gelatinization were investigated using microscopy. Pressure had a more significant effect on rheological and textural properties, followed by T and treatment t (in that order). Gel aging in HHP-treated CF slurries during storage was supported by rheological measurements.

Influence of acid hydrolysis on thermal and rheological properties of amaranth starches varying in amylose content

BACKGROUND

The granules of amaranth starch are very small compared with starches from other sources. In the current work, amaranth starches with different amylose contents were treated with hydrochloric acid as a function of time in order to study the effect of acid treatments on starches. Differential scanning calorimetry and dynamic oscillation in shear were employed to analyse the thermal and rheological properties of acid-modified amaranth starch.

RESULTS

Results showed that gelatinisation temperatures and enthalpy change of gelatinisation (ΔH) decreased steeply initially, and had a slight increase with further treatment up to 12 h then decreased, an outcome that reflected distinct resistance to acid with various amylose contents. Rheological parameters of storage and loss moduli during heating, cooling and frequency sweep of modified starches reflected the differential scanning calorimetry results by decreasing in value as the time of acid hydrolysis increased.

CONCLUSION

With amylose content increase, the effects of acid hydrolysis on gelatinisation temperatures became less pronounced. Nevertheless, prolonged acid hydrolysis decreased the storage and loss moduli, with the starch pastes becoming more liquid-like.

Impact of the soak and the malt on the physicochemical properties of the sorghum starches

Starches were isolated from soaked and malted sorghum and studied to understand their physicochemical and functional properties. The swelling power (SP) and the water solubility index (WSI) of both starches were nearly similar at temperatures below 50 °C, but at more than 50 °C, the starch isolated from malted sorghum showed lower SP and high WSI than those isolated from raw and soaked sorghum. The pasting properties of starches determined by rapid visco-analyzer (RVA) showed that malted sorghum starch had a lower viscosity peak value (86 BU/RVU) than raw sorghum starch (454 BU/RVU). For both sorghum, X-ray diffractograms exhibited an A-type diffraction pattern, typical of cereal starches and the relative degrees of crystallinity ranged from 9.62 to 15.50%. Differential scanning calorimetry (DSC) revealed that raw sorghum starch showed an endotherm with a peak temperature (Tp) at 78.06 °C and gelatinization enthalpies of 2.83 J/g whereas five-day malted sorghum starch had a Tp at 47.22 °C and gelatinization enthalpies of 2.06 J/g. Storage modulus (G′) and loss modulus (G″) of all starch suspensions increased steeply to a maximum at 70 °C and then decreased with continuous heating. The structural analysis of malted sorghum starch showed porosity on the granule’s surface susceptible to the amylolysis. The results showed that physicochemical and functional properties of sorghum starches are influenced by soaking and malting methods.