Optimizing the Conditions for Starch Dry Phosphorylation with Sodium Mono- and Dihydrogen Orthophosphate under Heat and Vacuum

Impact of pH on physicochemical properties of corn starch by dry heat treatment

This study investigated the effects of temperature, pH, and starch genotype on starch characteristics after dry heat treatment (DHT). DHT starches were prepared according to 19 DHT conditions, constructed using a D-optimal design, and analyzed with respect to apparent amylose (AAM) content, X-ray diffraction (XRD) pattern, relative crystallinity (RC), solubility and swelling power (SP), thermal properties, and pasting viscosity. The DHT starches maintained their granular structures even after DHT at pH 3, although there was some damage to their granular surfaces. The DHT starches showed lower amylose content, RC, SP, gelatinization temperature and enthalpy, degree of retrogradation, and pasting viscosity, but higher solubility, compared to those of native starches. These DHT effects were more pronounced as pH decreased at each temperature, regardless of the starch genotype. Overall, DHT can be used to expand the physical functionality of high-amylose and highly crystallized starches with poor properties.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01353-7.

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.

Flame Retardancy of Wood Fiber Materials Using Phosphorus-Modified Wheat Starch

Biopolymer-based flame retardants (FR) are a promising approach to ensure adequate protection against fire while minimizing health and environmental risks. Only a few, however, are suitable for industrial purposes because of their poor flame retardancy, complex synthesis pathway, expensive cleaning procedures, and inappropriate application properties. In the present work, wheat starch was modified using a common phosphate/urea reaction system and tested as flame retardant additive for wood fibers. The results indicate that starch derivatives from phosphate/urea systems can reach fire protection efficiencies similar to those of commercial flame retardants currently used in the wood fiber industry. The functionalization leads to the incorporation of fire protective phosphates (up to 38 wt.%) and nitrogen groups (up to 8.3 wt.%). The lowest levels of burning in fire tests were measured with soluble additives at a phosphate content of 3.5 wt.%. Smoldering effects could be significantly reduced compared to unmodified wood fibers. The industrial processing of a starch-based flame retardant on wood insulating materials exhibits the fundamental applicability of flame retardants. These results demonstrate that starch modified from phosphate/urea-systems is a serious alternative to traditional flame retardants.

Biodegradable pH-sensitive prospidine-loaded dextran phosphate based hydrogels for local tumor therapy

The paper focuses on the development of drug delivery systems based on hydrogels of dextran phosphate (DP) for local cancer therapy. The hydrogels were characterized by physicochemical properties including functional group content, morphology, gel fraction, pH-responsive swelling. The desirable pH-sensitive drug release behavior of these hydrogels was demonstrated by a drug release test with Prospidine-loaded hydrogels (DP-Pr hydrogels) at different pH values. In vitro degradation of the DP-Pr hydrogels was determined under simulated physiological conditions. The cytotoxicity of the blank DP hydrogels and DP-Pr hydrogels with different Pr concentrations was evaluated with HeLa and HЕр-2 cells. Investigations of antitumor efficiency in vivo showed that administration of DP-Pr hydrogels in comparison with an aqueous solution of Pr results in the increase of antitumor activity, prolongation of therapeutic action and growth of a number of animals cured. Therefore, such pH-responsive DP hydrogels could be promising candidates as drug delivery carriers.

Phosphorylation of bio-based compounds: the state of the art

The aim of this review is to present both fundamental and applied research on the phosphorylation of renewable resources, through reactions on naturally occurring functions, and their use in biobased polymer chemistry and applications.

Properties and characteristics of dual-modified rice starch based biodegradable films

In this study, the dual-modified rice starch was hydroxypropylated with 6-12% of propylene oxide followed by crosslinking with 2% sodium trimetaphosphate (STMP) and a mixture of 2% STMP and 5% sodium tripolyphosphate (STPP). Increasing the propylene oxide concentrations in the DMRS yielded an increase in the molar substitution (MS) and degree of substitution (DS). However, the gelatinization parameters, paste properties, gel strength and paste clarity showed an inverse trend. The biodegradable films from the DMRS showed an increase the tensile strength, elongation at break and film solubility, while the transparency value decreased when the concentration of propylene oxide increased. However the water vapor permeability of the films did not significantly change with an increase in the concentration of propylene oxide. In addition, it was found that DMRS films crosslinked with 2% STMP demonstrated higher tensile strength, transparency value and lower water vapor permeability than the DMRS films crosslinked with a mixture of 2% STMP and 5% STPP. The XRD analysis of the DMRS films showed a decrease in crystallinity when the propylene oxide concentrations increased and the crystallinity of DMRS films with 2% STMP were higher than the DMRS films with a mixture of 2% STMP and 5% STPP.

Comparison of A and B starch granules from three wheat varieties

Three starches from the wheat varieties AK58, ZM18 and YZ4110 were separated into large (A) and small (B) granules, which were characterized structurally and evaluated for their functional properties. SEM results showed that the size of A-granules from ZM18 and YZ4110 were about the same, but the sizes of A-granules and B-granules from AK58 were larger than those of ZM18 and YZ4110. FTIR spectra showed that all the samples exhibited a similar pattern, with seven main modes with maximum absorbance peaks near 3,500, 3,000, 1,600, 1,400, 1,000, 800, 500 cm⁻¹. The B-granules of ZM18 and YZ4110 had less amylose content, although the difference among the total amylose contents of the three unfractionated starches was not significant. X-ray diffraction (XRD) patterns showed predominantly A-type crystallinity for all the starches. The A-granules showed sharper XRD patterns than the other starches. DSC analysis showed that the A-granules had broader ranges of gelatinization temperatures than the B-granules from the same wheat variety. The gelatinization enthalpy (ΔH) of A-granules was higher than that of B-granules. AK58 exhibited the smallest enthalpy, while ZM18 showed the largest enthalpy. In pasting tests, the A-granule starch of AK58 had higher peak, final and setback viscosity, lower breakdown and pasting temperature, and the B-granule starch and unfractionated starch of AK58 had lower peak, breakdown, final and setback viscosity and higher pasting temperature than ZM18 and YZ4110.

Preparation of phosphorylated starch by dry-heating in the presence of pyrophosphate and its calcium-phosphate solubilizing ability

Starch was phosphorylated through dry-heating in the presence of pyrophosphate at various conditions, and the characteristics of phosphorylated starch (PS) were examined. Starch phosphorylation increases as the pH increases from 3 to 6, but diminishes at pH 7. Increased temperatures enhance phosphorylation. Data from (31)P NMR suggests that starch phosphorylation occurs mainly at the C3-OH and C6-OH of the glucose residue. The phosphate linkage is mainly due to monostarch monophosphate. Although starch had almost no calcium phosphate-solubilising capacity, this capacity was markedly enhanced by phosphorylation. X-ray diffraction analysis indicates that the crystal structure of hydroxyapatite was not present in the calcium phosphate-PS complex.

Improvement of Functional Properties of Whey Protein Isolate Through Glycation and Phosphorylation by Dry Heating

Whey protein isolate (WPI) was glycated with maltopentaose (MP) through the Maillard reaction, and the MP-conjugated WPI (MP-WPI) was then phosphorylated by dry heating in the presence of pyrophosphate. Glycation occurred efficiently, and the sugar content of WPI increased approximately 19.9% through the Maillard reaction. The phosphorylation of MP-WPI was enhanced with an increase in the dry-heating time from 1 to 5 d, and the phosphorus content of WPI increased approximately 1.05% by dry heating at pH 4.0 and 85 degrees C for 5 d in the presence of pyrophosphate. The electrophoretic mobility of WPI increased with an increase in the phosphorylation level. The stability of WPI against heat-induced insolubility at pH 7.0 was improved by conjugation with MP alone, and further improved by phosphorylation. Although the emulsifying activity of WPI was barely affected by glycation and phosphorylation, the emulsifying stability of phosphorylated MP-WPI (5 d), was 2.2 times higher than that of MP-WPI. Gelling properties such as hardness, resiliency, and water-holding capacity of heat-induced WPI gel were markedly improved, and the gel was rendered transparent by phosphorylation. The calcium phosphate-solubilizing ability of WPI was enhanced by phosphorylation. These results suggested that phosphorylation by dry heating in the presence of pyrophosphate after conjugation with MP is a useful method for improving the functional properties of WPI.

Starch — Value Addition by Modification

Starch is one of the most important but flexible food ingredients possessing value added attributes for innumerable industrial applications. Its various chemically modified derivatives offer a great scope of high technological value in both food and non-food industries. Modified starches are designed to overcome one or more of the shortcomings, such as loss of viscosity and thickening power upon cooking and storage, particularly at low pH, retrogradation characteristics, syneresis, etc., of native starches. Oxidation, esterification, hydroxyalkylation, dextrinization, and cross-linking are some of the modifications commonly employed to prepare starch derivatives. In a way, starch modification provides desirable functional attributes as well as offering economic alternative to other hydrocolloid ingredients, such as gums and mucilages, which are unreliable in quality and availability. Resistant starch, a highly retrograded starch fractionformed upon food processing, is another useful starch derivative. It exhibits the beneficial physiological effects of therapeutic and nutritional values akin to dietary fiber. There awaits considerable opportunity for future developments, especially for tailor-made starch derivatives with multiple modifications and with the desired functional and nutritional properties, although the problem of obtaining legislative approval for the use of novel starch derivatives in processed food formulations is still under debate. Nevertheless, it can be predicted that new ventures in starch modifications and their diverse applications will continue to be of great interest in applied research.