Application of digital image analysis method to study the gelatinization process of starch/ sodium chloride solution systems

Effects of NaCl on the Physical Properties of Cornstarch-Methyl Cellulose Blend and on Its Gel Prepared with Rice Flour in a Model System

This study investigated the impact of NaCl on the physical properties of cornstarch-methyl cellulose (CS-MC) mixtures and their gels prepared with rice flour in a model system. Opposite trends were observed, showing that NaCl led to decreased viscosity of the CS-MC mixtures (liquid-based), whereas a more stable and robust structure was observed for the rice-flour-added gels (solid-based) with the addition of NaCl. The interference of NaCl with the CS-MS blend's ability to form a stable gel network resulted in a thinner consistency, as the molecules of the CS-MS blend may not bind together as effectively. On the contrary, NaCl showed the potential to enhance the protein network within CS-MC gels prepared with rice flour, thereby contributing to an augmentation in the stability or firmness of the cooked gels. Careful utilization of NaCl to optimize the physical properties of the CS-MC blends, as well as the gels based on rice flour, should be performed.

Starch modification through its combination with other molecules: Gums, mucilages, polyphenols and salts

Apart from its non-toxicity, biocompatibility and biodegradability, starch has demonstrated eminent functional characteristics, e.g., forming well-defined gels/films, stabilizing emulsions/foams, and thickening/texturizing foods, which make it a promising hydrocolloid for various food purposes. Nonetheless, because of the ever-increasing range of its applications, modification of starch via chemical and physical methods for expanding its capabilities is unavoidable. The probable detrimental impacts of chemical modification on human health have encouraged scientists to develop potent physical approaches for starch modification. In this category, in recent years, starch combination with other molecules (i.e., gums, mucilages, salts, polyphenols) has been an interesting platform for developing modified starches with unique attributes where the characteristics of the fabricated starch could be finely tuned via adjusting the reaction parameters, type of molecules reacting with starch and the concentration of the reactants. The modification of starch characteristics upon its complexation with gums, mucilages, salts, and polyphenols as common ingredients in food formulations is comprehensively overviewed in this study. Besides their potent impact on physicochemical, and techno-functional attributes, starch modification via complexation could also remarkably customize the digestibility of starch and provide new products with less digestibility.

Sensory, structural breakdown, microstructure, salt release properties, and shelf life of salt-coated air-dried yellow alkaline noodles

Salt reduction in food has been employed to improve public health. The effects of salt coatings on sodium content, sensory properties, structural breakdown, microstructure, salt release properties, and shelf life of yellow alkaline noodles (YAN) were evaluated. 15 g/dL resistant starch HYLON™ VII (HC) or 5% (v/v) Semperfresh™ (SC) with 10, 20, and 30 g/dL sodium chloride (NaCl) were used. HC-Na30 and SC-Na30 had the highest sodium content and came closest to commercial YAN in taste and saltiness perception. Structural improvement was demonstrated with HC-Na10 and SC-Na10 as both noodles required maximum work to be broken down. Moreover, SEM micrographs of these noodles showed a more compact and dense appearance with increased continuity of the matrix and fewer voids and hollows. However, ruptured surfaces were observed in noodles coated with 20 and 30% salt. The enhanced salt release from the coatings was demonstrated in an in vivo analysis, with the released salt occurring rapidly from HC and SC coatings. HC-Na10 and SC-Na10 noodles had a shelf life of more than 8 days when stored at 4 °C, which is longer than HC-Na0 and SC-Na0 noodles. Storage at 4 °C decelerated the microbiological growth, changes in pH and CIE L* values in salt-coated noodles than storage at 25 °. Thus, HC-Na10 and SC-Na10 could be suitable formulations to replace commercial YAN.

Effect of NaCl addition on alcohol-alkali-treated waxy rice starch: Structural and physicochemical functionality

The physicochemical and structural properties of waxy rice starch (WRS) and alcohol-alkali-treated waxy rice starch (AAT-WRS) were determined in the presence of different concentrations of NaCl (0, 2, 4, 6 and 8%). The results showed that NaCl decreased the transparency of WRS and AAT-WRS pastes, but enhanced both freeze-thaw stability and apparent viscosity (p < 0.05). The rheological measurement results showed that the addition of NaCl could improve the modulus values of both WRS and AAT-WRS, and the effect on WRS was more significant than that on AAT-WRS. The textural parameters of WRS pastes were evidently enhanced by NaCl, but the presence of NaCl had no significant effect on the firmness of AAT-WRS pastes. The results of SEM and FT-IR revealed that NaCl could protect the granular morphology and increase the degree of short-range order of WRS and AAT-WRS.

Insights into the gelatinization of potato starch by in situ 1H NMR

The gelatinization of potato starch and the effect of NaCl on starch gelatinization were monitored successfully in situ by 1H NMR spectroscopy. Variable temperature (VT) 1H NMR measurement, from 316 K to 340 K, was conducted on a suspension of potato starch and deuterium water as well as a mixture of potato starch, NaCl and deuterium water. The hydration level of starch was determined with the increase of temperature. In the presence of NaCl, the initial gelatinization temperature of potato starch was decreased from 331 to 328 K. Meanwhile, in situ 1H NMR spectroscopy as a function of time was also carried out to monitor the gelatinization with a time resolution of 90 s per spectrum. Furthermore, the effect of using different processing methods during gelatinization, including varying the temperature or time duration, was investigated in detail. It was confirmed that protons from different groups of starch showed different accessibility for water during hydration of starch granules. In comparison with temperature, gelatinization time as the major factor for reaching complete gelatinization was confirmed. We expect that this research, as a continuing effort to apply NMR spectroscopy for characterizing starch, will pave a new way in the structural elucidation of starch.

Effects of salts on the freeze-thaw stability, gel strength and rheological properties of potato starch

The objective of this study was to evaluate the effects of different salts (NaF, NaCl, NaBr, NaI, K2SO4, KCl, KNO3, KSCN, LiCl) on freeze-thaw stability, gel strength and rheological properties of potato starch. Addition of the structure-making (salting-out) ions, such as F- and SO42-, decreased freeze-thaw stability and increased gel strength, maximal storage modulus (G') and maximal loss modulus (G″) of potato starch, due to a stronger three-dimensional network by promoting the starch retrogradation and inhibiting starch gelatinization. Shear stress versus shear rate of all samples at 25 °C was well fitted to the simple power-law model with high determination coefficients (R2 = 0.9863-0.9990). Flow behavior index (n), consistency index (K) and apparent viscosities increased with adding salting-out ions. However, the structure-breaking (salting-in) ions had reverse effects on freeze-thaw stability, gel strength and rheological characteristics of potato starch. The addition of structure-breaking ions, such as Br-, NO3-, I-, SCN-, Na+ and Li+, decreased gel strength, G' and G″ values and increased freeze-thaw stability. Salts could significantly influence on the retrogradation of potato starch, generally following the ion order: F- > SO42- > Cl- > Br- > NO3- > I- > SCN- for anions and K+ > Na+ > Li+ for cations, consistent with the Hofmeister series.