Phytate-mediated phosphorylation of maize, rice, and potato starches at different pH conditions

Structure and functional characteristics of starch from different hulled oats cultivated in China

This work aimed to evaluate the structure and functional characteristics of starch from ten hulled oat cultivars grown in different locations in China. The protein, phosphorus, amylose, and starch contents were 0.2-0.4 %, 475.7-691.8 ppm, 16.2-23.0 %, and 93.6-96.7 %, respectively. All the starches showed irregular polygonal shapes and A-type crystallization with molecular weights ranging from 7.2 × 107 to 4.5 × 108 g/mol. The amounts of amylopectin A (DP 6-12), B1 (DP 13-24), B2 (DP 25-36), and B3 (DP > 36) chains were in the ranges of 10.3-16.0 %, 54.5-64.8 %, 16.5-21.1 %, and 4.9-13.1 %, respectively. The starches differed significantly in gelatinization temperatures, pasting viscosity, solubility, swelling power, rheological properties, and digestion parameters. The results revealed that the larger particle size could increase the peak viscosity of the starch paste. The presence of phosphorus increased the gelatinization temperature and enhanced the resistant starch content. The starch granules with higher crystallinity contained a higher proportion of phosphate, which increased final viscosity and setback viscosity but decreased rapidly digestible starch. Overall, oat starch with a high phosphorus content could be used to prepare low-glycemic-index food for diabetes patients.

Effect of ethanol, phytic acid and citric acid treatment on the physicochemical and heavy metal adsorption properties of corn starch

Corn starch dispersions were heated with ethanol (E) and reacted with phytic acid (E-PA), citric acid (E-CA), and a mixture of phytic and citric acid (E-PACA) under dry-heating to prepare heavy metal adsorbents. Microscopy images indicated that ethanol treatment induced the formation of porous structures on the surface; furthermore, treatment with phytic and citric acid induced indentations, pores, and irregular structures in E-PA, E-CA, and E-PACA starches. Phytic and citric acid were retained in the starch molecules through ester bonds with the phosphate and carboxyl groups, respectively. Starch esterification by phytic and citric acid induced a loss of crystallinity, high water absorption capacity, and low solubility. E-PACA starch exhibited more efficient Cu2+ adsorption (38.13 mg/g) than native, E, E-PA, and E-CA starches (0.11, 0.49, 2.05, and 36.23 mg/g, respectively). Thus, modification with ethanol, phytic acid and citric acid can be applied to prepare natural starch-based heavy metal adsorbents.

Enhancing micronutrient absorption through simultaneous fortification and phytic acid degradation

Phytic acid (PA), an endogenous antinutrient in cereals and legumes, hinders mineral absorption by forming less bioavailable, stable PA-mineral complexes. For individual micronutrients, the PA-to-mineral molar ratio below the critical level ensures better bioavailability and is achieved by adding minerals or removing PA from cereals and pulses. Although several PA reduction and fortification strategies are available, the inability to completely eradicate or degrade PA using available techniques always subdues fortification's impact by hindering fortified micronutrient absorption. The bioavailability of micronutrients could be increased through simultaneous PA degradation and fortification. Following primary PA reduction of the raw material, the fortification step should also incorporate additional essential control stages to further PA inactivation, improving micronutrient absorption. In this review, the chemistry of PA interaction with metal ions, associated controlling parameters, and its impact on PA reduction during fortification is also evaluated, and further suggestions were made for the fortification's success.

Phosphorylation and citration of normal corn starch by dry heating with phytic acid and citric acid

Normal corn starch was subjected to dry heating in the presence of phytic acid (PA, 2 %, starch basis) and citric acid (CA, 5 % and 10 %) for modification. Dual treatment with PA and CA induced structural and physicochemical changes in normal corn starch. Phosphorus concentration, degree of substitution, FTIR, and ³¹P NMR analyses confirmed esterification of starch by dry heating with PA and CA. Both phosphorylation and citration by esterification with PA and CA were observed in PA + 5CA starch, but high CA concentration inhibited covalent interaction between PA and starch in PA + 10CA starch. The degree of phosphorylation and citration resulted in different physicochemical properties in starch treated with PA and CA. The treatment with only PA did not change the crystalline regions of PA starch, but CA treatment induced the disruption of the crystalline structure of PA + 5CA and PA + 10CA starch. PA starch showed high solubility (46.41 %) and transmittance (90.51 %), but dual treatment of PA and CA induced significant decrease in solubility (3.23 %) and transmittance (2.18 %) of PA + 10CA starch. CA treatment increased the fraction of resistant starch in non-cooked (72.44 %) and cooked PA + 10CA starch (42.76 %). Therefore, dual treatment with PA and CA had potential to control physicochemical and functional properties of starch by phosphorylation and citration of starch.

Physicochemical properties of a new starch from turion of Spirodela polyrhiza

Starch from the turion of Spirodela polyrhiza ZH0196 is a new resource with great development values. The solubility, swelling power, thermogravimetric analysis (TGA), enzyme susceptibility, and in vitro digestibility of Spirodela starch, paste clarity, settling volume, and the rheology property of Spirodela starch paste, strength, elasticity, and freeze-thaw stability of Spirodela starch gel were studied. The properties of Spirodela starch were compared with those of normal corn starch and rice starch. The possible relationship between properties and structure of three kinds of starch was analyzed by principal component analysis (PCA). The results showed that the rapidly digested starch, slowly digested starch and resistant starch were 86.63 %, 4.43 %, and 8.94 % respectively. Spirodela starch has higher strength (17.77 g), elasticity (4.98 g/s) of starch paste, and freeze-thaw stability of starch gel than those of normal corn starch and rice starch. The rheological results showed that the stickiness maintainability of starch paste was normal corn > Spirodela > rice and Spirodela starch paste had compact paste structures with the tan δ between 0.33 and 0.38. This study has significant value in the application of Spirodela starch.

Preparation and structural properties of starch phosphate modified by alkaline phosphatase

In this study, a method for the synthesis of starch phosphate using the transferase properties of alkaline phosphatase was explored. Maize starch was treated with a pyrophosphate solution containing alkaline phosphatase and catalytic ions under pH 8 at 37 °C. The synthesis of starch phosphate was evaluated and compared with untreated and treated starch controls. The phosphorus content of the samples increased up to 8500% with the catalytic ion concentration, whereas the peak viscosity by up to 41.4% decreased. The crystallinity and enthalpy of the phosphorylated samples were reduced by up to 26.8% and 23.3%, respectively; however, no significant was observed by Fourier-transform infrared spectrometer. The roughness of the starch surface and the distribution of elemental phosphorus were observed by scanning electron microscopy and energy dispersive Spectrometry. X-ray photoelectron spectroscopy and time of flight secondary ion mass spectrometry results further indicated the grafting of the phosphate radical.

Flame Retardant Functionalization of Microcrystalline Cellulose by Phosphorylation Reaction with Phytic Acid

The functionalization of microcrystalline cellulose (MCC) is an important strategy for broadening its application fields. In the present work, MCC was functionalized by phosphorylation reaction with phytic acid (PA) for enhanced flame retardancy. The conditions of phosphorylation reaction including PA concentration, MCC/PA weight ratio and temperature were discussed, and the thermal degradation, heat release and char-forming properties of the resulting PA modified MCC were studied by thermogravimetric analysis and pyrolysis combustion flow calorimetry. The PA modified MCC, which was prepared at 90 °C, 50%PA and 1:3 weight ratio of MCC to PA, exhibited early thermal dehydration with rapid char formation as well as low heat release capability. This work suggests a novel strategy for the phosphorylation of cellulose using PA and reveals that the PA phosphorylated MCC can act as a promising flame retardant material.

Effect of combination of dry heating and glucose addition on pasting and gelling behavior of starches

Normal corn, waxy corn, potato, and tapioca starches were subjected to dry heating by adding glucose at slightly alkaline conditions to investigate the impact of the combination of dry heating and glucose addition. After dry heating, normal/waxy corn and tapioca starches showed increased peak viscosity and decreased pasting temperatures, whereas potato starch exhibited decreased peak viscosity. The increase in peak viscosity of normal/waxy corn and tapioca starches became more significant after adding glucose to the dry heating process. Moreover, the starch gels became more rigid after dry heating with the addition of glucose than native and control starch. Dry heating alone decreased the melting temperatures and enthalpy of the starches assessed. Nevertheless, dry heating with glucose addition induced no significant changes in the melting characteristics of corn and tapioca starches; however, it significantly increased the melting temperature and enthalpy of potato starch compared to those by dry heating alone. Furthermore, dry heating in combination with glucose addition reduced paste clarity and induced slight thermal browning. These results clearly indicate that the combination of dry heating and glucose addition induces more intense changes in the properties of starch than those by dry heating or glucose addition alone.