Effects of microwave-discharged cold plasma on synthesis and characteristics of citrate derivatives of corn starch granules

Effect of (multi pin) atmospheric cold plasma treatment on curcumin extraction and investigating phytochemicals, antioxidants, physical and morphological properties of turmeric (Curcuma longa L.) powder

This investigation was focused on the impact of cold plasma (CP) on the extraction of curcumin and bioactive compounds of turmeric powder (TP). TP was treated with CP at different applied voltages (10, 20, and 30 kV), with various exposure times (10, 20, and 30 min). The curcumin content was highest at 30 kV for 10 min with a yield of 46.49 mg/g of TP. Total phenols significantly (p < 0.05) enhanced from 163.91 to 360.78 mg GAE/g DW accompanied by a remarkable 16% increment in total flavonoids, paralleled by a 26% increment in antioxidants as of control. Nuclear magnetic resonance spectra justified the extraction of curcuminoids. Moreover, micrographs displayed cell lysis in the treated powder. CP has exhibited a positive effect on surface colour parameters and thermal properties of TP. Overall, CP technology can be tailored for better curcumin extraction and the enhancement of phytochemicals.

Cold plasma treatment to improve jelly production using a fused deposition modeling 3D printer

Herein, the effects of cold plasma (CP) on the rheological properties of gelatin-based solutions for 3D jelly printing using a fused deposition modeling method were investigated. The gelatin powder was packaged in a nylon/polyethylene pouch with nitrogen gas and subjected to CP treatment at 15 W for 10 min using atmospheric dielectric barrier discharge plasma treatment. CP treatment reduced the relative proportion of polar functional groups on the surface of the gelatin powder and forged new bonds (e.g., C-C) that reduced the hydrophilicity of the material. Furthermore, it increased the storage modulus and yield stress of the jelly formulation and lowered the phase angle, improving the fidelity and shape retention of the 3D printed jelly. Using CP-treated gelatin, inferior jelly formulations could be tuned to satisfy established printing criteria. CP treatment can control the rheological properties involved in the 3D printing of jelly.

Nonthermal physical modification of starch: An overview of recent research into structure and property alterations

To tailor the properties and enhance the applicability of starch, various ways of starch modification have been practiced. Among them, physical modification methods (micronization, nonthermal plasma, high-pressure, ultrasonication, pulsed electric field, and γ-irradiation) are highly potential for starch modification considering its safety, environmentally friendliness, and cost-effectiveness, without generating chemical wastes. Thus, this article provides an overview of the recent advances in nonthermal physical modification of starch and summarizes the resulting changes in the multi-level structures and physicochemical properties. While the effect of these techniques highly depends on starch type and treatment condition, they generally lead to the destruction of starch granules, the degradation of molecules, decreases in crystallinity, gelatinization temperatures, and viscosity, increases in solubility and swelling power, and an increase or decrease in digestibility, to different extents. The advantages and shortcomings of these techniques in starch processing are compared, and the knowledge gap in this area is commented on.

Talipot palm (Corypha umbraculifera L.) a nonconventional source of starch: Effect of citric acid on structural, rheological, thermal properties and in vitro digestibility

Starch from talipot palm trunk (Corypha umbraculifera L.), a new starch source, was treated with different citric acid concentrations (5%, 10%, 20%, and 40% of the dry weight of starch) to produce citrate starch. The influence of citric acid treatment on physicochemical, pasting, structural, thermal, rheological, and digestibility properties of talipot palm starch were studied. A new peak at 1728 cm^-1 was observed in the Fourier-transform infrared spectroscopy (FTIR) spectra of citric acid-treated starches, which confirmed the formation of an ester bond between starch molecule and citric acid. The crystalline pattern of talipot palm starch was unaffected by citric acid treatment, whereas the relative crystallinity decreased from 16.35% to 3.06%. The Rapid Visco Analysis of starch treated with citric acid did not show any characteristic peaks, however, the untreated starch showed a peak viscosity of 3646 cP. The gelatinization parameters decreased with an increase in the degree of substitution, and the enthalpy of gelatinization (ΔH_gel) decreased from 11.19 J/g to 6.37 J/g. The in-vitro digestibility of talipot palm starch was decreased by citric acid treatment, and that of the slowly digestible starch (SDS) and resistant starches (RS) increased significantly (p ≤ 0.05) from 31.71% to 39.43% and 37.55% to 53.38%, respectively.

Production and Properties of Starch Citrates-Current Research

Starch modification by chemical reaction is widely used to improve the properties of native starch. Modified by citric acid, starch is characterized by specific properties resulting from the presence of citrate residues and as a result of cross-linking starch. The chemicals used for preparing starch citrates are safe for human health and the natural environment compared to the harsh chemicals used for conventional modifications. Starch citrates are traditionally produced by heating starch-citric acid mixtures in semi-dry conditions or by a heat moisture treatment. The conditions of the modification process (roasting temperature, heating time, citric acid dose) and the botanic source or genotype of starch determine the degree of substitution and the properties of the obtained preparations. Changes of starch properties occurring during esterification lead to reduced relative crystallinity, resulting in a decrease in the affinity for water, the gelatinization parameters, and the viscosity of starch citrate. However, one of the most important outcome of the modification is the formation of resistant starch (RS), which has increased resistance to the action of amylolytic enzymes. Currently, new methods for producing starch citrates with improved functional and rheological properties while maintaining the highest possible content of resistant starch are being sought. The article presents an overview of recent studies on the production, properties. And applicability of starch citrates with special attention paid to their role as preparations of resistant starch (RS). The use of citric acid for modification of starch is better for the technology process, while using cross-linking is better than simply using esterification.

Effect of the Esterification of Starch with a Mixture of Carboxylic Acids from Yarrowia lipolitica Fermentation Broth on Its Selected Properties

Potato starch was esterified with carboxylic acids contained in the fermentation broth from Yarrowia lipolitica yeast production. Various acid concentrations and various roasting temperatures were used to determine effects of process conditions on ester properties, including the number of acid residues attached to starch chains, starch susceptibility to amylolysis, and thermal characteristics of starch phase transitions. Study results demonstrated the effect of both the composition and the dose of the fermentation broth and of roasting temperature of starch on the number of acid residues attached to starch chains. Citric acid was more susceptible to esterification with starch (DS = 5.65%) compared to the α-ketoglutaric acid (DS = 0.12%). In the case of the latter, a higher degree of substitution was determined in the esters produced at higher roasting temperatures. The lowest digestibility (RS = 20%) was demonstrated for the starch esters with the highest degree of substitution with citric acid, whereas all starch esters showed decreased values of the thermal characteristics of pasting.

Impact of static and dynamic modes of semi-dry heat reaction on the characteristics of starch citrates

The objective of this study was to demonstrate the validity of dynamic semi-dry heat reaction (SDHR) by investigating the effects of static and dynamic SDHR on the characteristics of starch citrates. The starch (normal and waxy corn)-citric acid (CA) mixture was heated in a convection oven (static mode) or a twin-screw extruder without a die (dynamic mode). The ester bonds of starch citrates were confirmed by FT-IR, and their molar degree of substitution did not differ between the reaction modes for the tested starch genotypes. Starch citrates by dynamic SDHR exhibited higher relative crystallinity, resistant starch content, solubility, swelling power, and gelatinization compared to those by static SDHR. Although static SDHR did not show a viscosity development during pasting, dynamic SDHR increased their pasting viscosities. Overall, these results suggest that dynamic SDHR could improve the defects (i.e., lack of solubility, swelling, and pasting attributes) of the traditional starch citrates.

Changes in the Structure and Digestibility of Wrinkled Pea Starch with Malic Acid Treatment

Resistant starch has gradually become a popular food component due to its beneficial physiological effects and heat resistance during processing. In this study, the structure, reaction mechanism, and digestibility of wrinkled pea starch with malic acid and heat⁻moisture treatment (HMT) are investigated. The degree of substitution (DS) of malate starch, HMT-malate starch, and malate-HMT starch was 0.164, 0.280, and 0.146, respectively. Malate starch remained in its complete particle form and pronounced birefringence was displayed. However, the malate-HMT starch sample was almost completely broken into pieces and lost the polarized cross. All modified starch samples had a decreased swelling power and a new peak at 1731⁻1741 cm-1 shown by FTIR. From the 13C CP/MAS NMR (Cross Polarizatio/Magic Angle Spinning Nuclear Magnetic Resonance) spectra, all the modified starches had extra peaks at 38.5 ppm and 172.8 ppm. After esterification treatment, the resistant starch (RS) and slowly digestible starch (SDS) content of starch samples increased dramatically. The higher content of RS and lower enzymatic hydrolysis rate of the malate starch could be used to produce low-calorie foods and have potential health benefits.