The effect of UV-B irradiation on structural and functional properties of corn and potato starches and their components.

In this work, UV-B irradiation, an environmentally friendly modification method, was applied to corn and potato carbohydrates. The influence of irradiation on starch properties was compared with that observed for starch oxidation with NaClO. The changes in the structures of starch carbohydrates were investigated by X-ray diffraction (XRD), electron paramagnetic resonance (EPR) and chromatographic methods. Functional properties such as viscosity, water binding capacity and solubility as well as pasting characteristics and thermodynamic parameters of gelatinization, resulting from structural changes were determined. UV-B irradiation was found to be a milder modification method than chemical oxidation. The potato carbohydrates, especially amylose, appeared to be more susceptible to changes upon irradiation, whereas corn ones, particularly amylopectin, were more stable and their properties changed to a smaller extent. Similarly, functional properties were not significantly influenced by UV-B treatment. EPR studies revealed the mechanism of depolymerization of starch carbohydrates via formation of stable carbon-centered radicals.

The effect of cassava and wheat starches complexation with selected fatty acids on their functional properties.

The aim of the study was to evaluate the impact of selected fatty acids: palmitic, stearic or oleic on functional properties of cassava and wheat starches. Effectiveness of complexation procedure was evaluated by determination of complexing index, lipids content and fatty acid composition. Native starches and their complexes with fatty acids were analyzed for water binding capacity and solubility in water, in vitro digestibility, pasting characteristic and rheological properties. On the basis of the obtained results it was found that values of complexing index values for both starches complexed with oleic acid were remarkably higher than those determined in palmitic or stearic counterparts. Starches complexation with fatty acids resulted in a significant increase in the percentage share of used fatty acid in total fatty acid composition. Presence of oleic acid in cassava starch significantly limited its water binding capacity and solubility in water. Complexation with all fatty acids used in the study resulted in an increase in final viscosity and rheological stability of cassava starch pastes. Wheat starch complexes with fatty acids were characterised by higher pasting temperatures as compared to non-complexed counterpart, with the greatest effect observed for starch-oleic acid complex. In most cases complexation of starches with fatty acids contribute to an increase in contents of resistant starch fraction. Analysis of rheological model parameters revealed that procedure of oleic acid complexation increased by twice the values of consistency coefficient, and significantly decreased flow index of both wheat and cassava starches. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13197-021-05153-x.

The effect of thermal and irradiation treatments on structural and physicochemical properties of octenyl succinate maize starches.

The aim of this paper was to evaluate the effect of thermal treatment and UV irradiation on structural and physicochemical properties of octenyl succinate (OS) maize starches differing in content of OS groups (0.76%-2.38%). X-ray diffraction (XRD), gel permeation chromatography (GPC), and electron paramagnetic resonance (EPR) spectroscopy were used to estimate structural characteristics of octenyl succinate starches and their physically treated counterparts. Starch functional properties were also determined. XRD spectra and hydrodynamic volume distribution revealed that growth of octenyl succinate groups' content resulted in stabilization of starch structure, which was confirmed by processes of radical formation, stimulated by thermal and UV treatments. It was found, on the basis of measurements of water binding capacity, water solubility and intrinsic viscosity, that OSA addition changed physicochemical properties of starch and influenced the course of physical modifications. It was established that temperature affected starch properties to a greater extent than UV.

Antioxidant properties, phenolic and mineral composition of germinated chia, golden flax, evening primrose, phacelia and fenugreek.

Seeds and sprouts are of considerable interest due to their numerous pro-health benefits. The aim of this study was to investigate the effect of germination on the mineral composition (performed by flame absorption atomic spectroscopy), total phenolic content, antioxidant activity, as well as phenolic profiles (before and after alkaline hydrolysis by high-performance liquid chromatography) of chia, golden flax, evening primrose, phacelia and fenugreek seeds. Generally, significant (p < 0.05) changes in the individual minerals composition of the seeds, improvement of their antioxidant properties, as well as increase in levels of individual phenolic compounds was found after seeds germination. Alkaline hydrolysis allowed to release free forms of phenolics and to confirm (chromatographically) their significantly higher amounts when compared to the nonhydrolyzed fraction. Gallic, protocatechuic, caffeic, p-coumaric, ferulic and sinapic acids, as well as quercetin and kaempferol were identified in analyzed seeds and sprouts. Sprouts exhibited better nutritional values than their un-germinated forms.

Impact of the degree of octenyl succinylation on metal ions complexation and functional properties of maize starch.

Modified maize starches were obtained by the esterification of native starch with octenyl succinic anhydride (OSA) at levels of 3% or 9%, and afterwards by its complexation with metal ions. The degree of substitution, contents of metal ions, hydrodynamic size distribution, intrinsic viscosity, pasting characteristics of the tested starches, and pastes surface tension were determined. Moreover, emulsions prepared from the modified starches were studied for oil droplet size distribution and storage stability. Reduction of hydrodynamic size and intrinsic viscosity was observed in octentyl succinate starch (OS starch) esterified with 3% OSA complexed with magnesium or calcium. The presence of potassium in both esterified starches increased their water binding capacity and solubility in water. In most cases, complexation with metal ions decreased viscosity of OS starch pastes. Emulsions prepared from the modified starches had smaller oil droplets and were more stable during storage, compared to the systems prepared from non-esterified starch.

Properties of potato starch treated with microwave radiation and enriched with mineral additives.

The paper discusses how microwave radiation and mineral additives affect selected physical and chemical properties of potato starch. Potato starch was irradiated with microwaves of 440 W or 800 W and then enriched with ions of potassium, magnesium, copper, or iron. Atomic absorption spectroscopy showed an effective incorporation of ions, while mineral saturation depended on both the microwave radiation density and the element being introduced. The data obtained prove that the microwave radiation and saturation with minerals affect the rheology and thermal characteristics of the samples under examination. Both the degree and the vector of the transformation depend on the microwave output and the mineral component introduced. Generation of radicals depends on starch degradation at high temperature while microwaves affect the number of the radicals formed. Amounts of the heat-generated radicals depend on the microwave output and the type of metal ions introduced into the starch structure.

Effect of mineral elements on physicochemical properties of oxidised starches and generation of free radicals.

The objective of this study was to determine the effect of enrichment of oxidised starches with mineral compounds on their physicochemical properties and capability for free radical generation. Potato and spelt wheat starches were oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. The modified starches were analysed for: content of mineral elements, colour parameters (L*a*b*), water binding capacity solubility in water at temperature of 50 and 80 °C, and susceptibility to enzymatic hydrolysis with α-amylase. In addition, thermodynamic characteristics of gelatinisation was determined by differential scanning calorimetry (DSC), and the number and character of thermally generated free radicals was assayed using electron paramagnetic resonance (EPR). Based on the results achieved, it was concluded that the quantity of incorporated minerals and changes in the assayed physicochemical parameters depended not only on the botanical type of starch but also on the type of the incorporated mineral element.