Preparing potato starch nanocrystals assisted by dielectric barrier discharge plasma and its multiscale structure, physicochemical and rheological properties

The effect of cold plasma on starch: Structure and performance

The inherent side effects of the physico-chemical properties of native starches often severely limit their use in food and non-food industries. Plasma is a non-thermal technology that allows rapid improvement of functional properties. This review provides a comprehensive summary of the sources and mechanisms of action of cold plasma and assesses its effects on starch morphology, crystal structure, molecular chain structure and physicochemical properties. The complex relationship between structure and function of plasma-treated starch is also explored. Potential applications of plasma-modified starch are also discussed in detail. The outcome of the modification process is influenced by factors such as starch type and concentration, plasma source, intensity and duration. The properties of starch can be effectively optimised using plasma technology. Plasma-based technologies therefore have the potential to modify starch to create a range of functionalities to meet the growing market demand for clean label ingredients.

Investigation of the role of sodium chloride on wheat starch multi-structure, physicochemical and digestibility properties during X-ray irradiation

In this paper, different NaCl content was added to wheat starch and then subjected to X-ray irradiation to investigate the effect of salt on starch modification by irradiation. The results showed that the degradation of wheat starch intensified with the increase in irradiation dose. When irradiated at the same dose, wheat starch with sodium chloride produced shorter chains, lower molecular weight and amylose content, and higher crystallinity, solubility, and resistant starch than wheat starch without sodium chloride. The energy generated by X-rays dissociating sodium chloride caused damage to the glycoside bonds of the starch molecule. With a further increase in the mass fraction of NaCl, the hydrogen bonds of the starch molecules were broken, and the double helix structure was depolymerized, which exacerbated the extent of irradiation-modified wheat starch. At the same time, starch molecules will be rearranged to form a more stable structure.

Correlation Study between Multi-Scale Structure and In Vitro Digestibility of Starch Modified by Temperature Difference

Physical techniques are widely applied in the food industry due to their positive impact on food quality and the environment. Temperature differences can effectively modify starch, but the resulting changes in starch structure and quality remain unclear. In this study, the corn starch was processed with high temperature, low temperature, and temperature difference (TD), including high temperature before low temperature (H-L) and low temperature before high temperature (L-H). The results showed that high temperature induced the umbilicus to concave inward shape and sharply decreased the amylose content, while low temperature increased the surface micropores and reduced the A-chain. TD reduced the fluorescence intensity and increased the clearness of the growth ring. TD elevated the relative crystallinity (RC), short-range order, A/B1 chains, hydrolysis parameters, and resistant starch (RS), and reduced amylose content, B2/B3 chains, and viscosity. Moreover, the corn starches treated by H-L had lower amylose content and higher RC, 1047/1022, A-chain, and RS than those treated by L-H. Overall, high temperature degraded the amylose and low temperature destroyed the amylopectin. During the TD, H-L can accelerate the starch molecular rearrangement more than the opposite temperature treatment order. These results will help produce novel starches for better food applications.

Effect of dielectric barrier discharge (DBD) plasma treatment on physicochemical and 3D printing properties of wheat starch

In recent years, the focus has shifted towards carbohydrate-based hydrogels and their eco-friendly preparation methods. This study involved an investigation into the treatment of wheat starch using dielectric barrier discharge (DBD) plasma technology over varying time gradients (0, 2, 5, 10, 15, and 20 min). The objective was to systematically examine the impact of different treatment durations on the physicochemical properties of wheat starch and the suitability of its gels for 3D printing. Morphology of wheat starch remained intact after DBD treatment. However, it led to a reduction in the amylose content, molecular weight, and crystallinity. This subsequently resulted in a decrease in the pasting temperature and viscosity. Moreover, the gels of the DBD-treated starch exhibited superior 3D printing performance. After a 2-min DBD treatment, the 3D printed samples of the wheat starch gel showed no significant improvements, as broken bars were evident on the surface of the 3D printed graphic, whereas DBD-20 showed better printing accuracy and surface structure, compared to the original starch without slumping. These results suggested that DBD technology holds potential for developing new starch-based gels with impressive 3D printing properties.

Starch nanoparticles with predictable size prepared by alternate treatments of ball milling and ultrasonication

In this study, starch nanoparticles (SNPs) were prepared by alternate treatments of liquid nitrogen ball milling and ultrasonication. The impact, shear and friction forces produced by ball milling, and acoustic cavitation and shear effects generated by ultrasonication disrupted starch granules to prepare SNPs. The SNPs possessed narrow particle size distribution (46.91-210.52 nm) and low polydispersity index (0.28-0.45). Additionally, the SNPs exhibited the irregular fragments with good uniformity. The relative crystallinity decreased from 34.91 % (waxy corn starch, WCS) to 0-25.91 % (SNPs), and the absorbance ratios of R1047/1022 decreased from 0.81 (WCS) to 0.60-0.76 (SNPs). The SNPs had lower thermal stability than that of WCS, characterized by a decrease in Td (temperature at maximum weight loss) from 309.39 °C (WCS) to 300.39-305.75 °C (SNPs). Furthermore, the SNPs exhibited excellent swelling power (3.48-28.02 %) and solubility (0.34-0.97 g/g). Notably, oil absorption capacity of the SNPs (9.77-15.67 g/g) was rather greater than that of WCS (1.33 g/g). Furthermore, the SNPs possessed the lower storage modulus (G'), loss modulus (G″) and viscosity than that of WCS. The SNPs with predictable size and high dispersion capability prepared in this study lay a foundation for expanding the application of SNPs.

High-efficiency preparation of starch nanocrystals with small size and high crystallinity by ethanol-acid penetration and dry-heating pretreatment

Ethanol-acid penetration and drying-heating treatment was developed to shorten the preparation time and improve the quality of starch nanocrystals (SNCs). After treatment by optimized parameters, including 40 % ethanol solution, 10.6 mM chloric acid, and heating time of 1.5 h or 2.0 h, the starches exhibited weakened internal structure and relatively complete crystalline structure. Compared with the regular preparation of only acid hydrolysis, the regular final yield (8.5 % after 5 days) was reached in 48 h and 12 h of the starch heated at 1.5 h and 2.0 h, respectively. The micromorphology, molecular weight, and crystalline structure evaluation demonstrated that the collected nanoparticles were indeed SNCs with smaller size and higher relative crystallinity than regular SNCs. Further analysis found that the SNCs had better crystalline lamellae, higher thermal stability, and lower proportion of phosphorus and sulfur atoms than regular SNCs. This provided a potential method for the high-efficiency preparation of SNCs.

Impact of cyclic and continuous dry heat modification on the structural, thermal, technological, and in vitro digestibility properties of potato starch (Solanum tuberosum L.): A comparative study

Dry heat treatment (DHT) has been demonstrated as a viable method for starch modification, offering benefits due to its environmentally friendly process and low operational costs. This research modified potato starch using different DHT conditions (continuous-CDHT and cyclic-RDHT), with durations ranging from 3 to 15 h and 1 to 5 cycles, at 120 °C. The study investigated and compared the structural, thermal, pasting, and morphological properties of the treated samples to those of untreated potato starch, including in vitro digestibility post-modification. DHT altered the amylose content of the biopolymer. X-ray diffraction patterns transitioned from type B to type C, and a decrease in relative crystallinity (RC%) was observed. Morphological changes were more pronounced in starches modified by RDHT. Paste viscosities of both CDHT and RDHT-treated starches decreased significantly, by 61.7 % and 58.1 % respectively, compared to native starch. The gelatinization enthalpy of RDHT-treated starches reduced notably, from 17.60 to 16.10 J g-1. Additionally, starch digestibility was impacted, with cyclic treatments yielding a significant increase in resistant starch content, notably an 18.26 % rise. These findings underscore the efficacy of dry heat in enhancing the functional properties of potato starch.

Understanding the improvement of sorghum starch acid hydrolysis modification by E-beam irradiation: A supramolecular structure perspective

To investigate the effect of E-beam irradiation (EBI) on acid-hydrolyzed starch, sorghum starch was pretreated with EBI (2, 4, and 8 kGy) and further hydrolyzed using hydrochloric acid (1 % and 6 % concentrations) in this study. EBI intensified acid hydrolysis corrosion on starch granule surfaces without inducing changes in the growth ring, FT-IR spectra, and crystal type (A-type). Also, EBI promoted starch degradation by acid hydrolysis, as evidenced by the R1047/1022 loss (1.071 to 1.027), the molecular weight decrease, and the chain length distribution shift (toward short A-chain). Moreover, this synergistic modification induced a starch enthalpy decrease (only 9.49 J/g) and crystallinity reduction (29.87 %), while solubility increase (34.27 %) and swelling power inhibition (only 7.65 g/g) were observed. Notably, starch digestibility was improved after synergistic modification. The obtained results broaden the processing depth of EBI in modified starch and highlight the promising application of acidolysis sorghum starch as a potential industrial starch.

The multi-scale structure changes of γ-ray irradiated potato starch to mitigate pasting/digestion properties

The comprehensive understanding of multi-scale structure of starch and how the structure regulates the pasting/digestion properties remain unclear. This work investigated the effects of γ-ray irradiation with different doses on multi-scale structure and pasting/digestion properties of potato starch. Results indicated that γ-ray at lower doses (<20 kGy) had little effect on micromorphology of starch, increased mainly the amylose content and the thickness of amorphous region while decreased crystallinity, double helix content and lamellar ordering. With the increase of dose, the internal structure of large granules was destroyed, resulting in the depolymerization of starch to form more short-chains and to reduce molecular weight. Meanwhile, amylose content decreased due to the depolymerization of amylose. The enhanced double helix content, crystallinity, lamellar ordering and structural compactness manifested the formation of the thicker and denser starch structure. These structure changes resulted in the decreased viscosity, the increased stability and anti- digestibility of paste.

A new sight separation for collecting starch nanocrystals with small size and high crystallinity based on the hydrolysis mechanism

To prevent starch nanocrystals (SNCs) that are generated at an early stage from being hydrolyzed excessively, this study proposed a new separation method, named "neutral dispersion and acidic precipitation." SNCs were prepared from waxy potato starch by sulfuric acid hydrolysis. Based on the results of kinetics and molecular weight, the hydrolysis was divided into three stages, e.g., rapid (initial 1 day), medium (subsequent 1 day) and slow stage (2-5 days). The rapid and medium stages were related to the degradation of amorphous region in starch, and the slow stage mainly referred to SNC release. Therefore, the method was developed to separate SNCs at the slow stage. After centrifugation at 6000 rpm, large particles were removed from the SNC suspension under pH 7. The SNCs with small average size and crystallite size, high relative crystallinity (RC), and high dispersion stability in the supernatant were retained and were then precipitated entirely under pH 5, because pH 5 led to the reduction of dispersion stability of SNCs. Meanwhile, the hydrothermal and dry-thermal stability of separated SNCs were significantly promoted. The separation method has the potential in SNC preparation for increasing the yield and collecting products with small size and high RC.

Understanding CaCl2 induces surface gelatinization to promote cold plasma modified maize starch: Structure-effect relations

To investigate the influence of surface gelatinization on cold plasma (CP) modification of starch, this study used CaCl2 to modify maize starch by surface gelatinization, further combined with CP treatment and characterized its multi-scale structure and physicochemical properties. The results revealed that starch surface gelatinization causes roughness and fragmentation on the granule surface, and CP undergoes etching effects. The synergistic modification promotes starch degradation, as evidenced by molecular weight decrease and short-chain ratio increase. Although the growth rings, FT-IR patterns, and crystal types of starch remained unchanged, the synergistic modification induced a reduction in the short-range orderliness and crystallinity of starch, thus causing a decrease in the pasting properties and contributing to its solubility. Notably, the CP treatment improved the RDS and SDS contents of the gelatinized starch due to more active sites on the granule surface after gelatinization, and this finding may provide insight into the deep processing of starch.

Electron beam irradiation-assisted prepare pea starch nanocrystals and characterization of their molecular structure, physicochemical and rheological properties

Electron beam irradiation (EBI) is an environmentally friendly physical modification technology. In this study, pea starch nanocrystals (SNC) were prepared by EBI-assisted pretreatment, and investigated the effects of EBI on the multiscale structure and physicochemical properties of SNC. EBI-assisted pretreatment didn't change the particle morphology, crystalline type and FT-IR spectra of SNC. However, EBI-SNC's relative crystallinity and short-range orderliness index (R1047/1022) significantly increased with increasing irradiation dose (5 KGy-20 KGy). In addition, EBI-assisted pretreatment caused the long chains of SNC's amylopectin to break into short chains. Moreover, EBI-assisted treatment significantly reduced the mean size, molecular weight, apparent amylose content, swelling power and SDS + RS content of SNC, while increasing the solubility, zeta potential and RDS content. Furthermore, the flow properties of the EBI-SNC samples were increased. The results show that EBI effectively changed the structural and functional properties of SNC, and the excellent functional properties are expected to broaden the application range of SNC.

Effect of electron beam irradiation on granular cold-water swelling chestnut starch: Improvement of cold-water solubility, multiscale structure, and rheological properties

In this study, granular cold-water swelling (GCWS) starch was prepared from chestnut starch by ethanol-alkali method, after which it was further modified by electron beam irradiation (EBI) technique to investigate the effect of EBI on GCWS chestnut starch. It was shown that the alcohol-alkali treatment disrupted the starch double helix structure and the starch crystalline form had been changed from "C" to "V" type. On this basis, EBI continued to act on the disrupted starch chains and further cleaved the long chains into short chains, which significantly improved the solubility of starch to 90.08 % in cold water at a 24 kGy irradiation dose. Therefore, this study can broaden the application scope of starch and provide new ideas for GCWS starch applications in food and water-soluble pharmaceutical industries.

Influence of pre- or post-electron beam irradiation on heat-moisture treated maize starch for multiscale structure, physicochemical properties and digestibility

Electron beam irradiation (EBI) as a green technological method for starch modification can generate starch-based materials with new functions. This study modified maize starch by heat-moisture treatment (HMT) for 1 h and 3 h, and EBI with various intensities (5 kGy and 10 kGy), and their effects of treatment sequence on the multiscale structure, physicochemical properties and in vitro digestibility were investigated. EBI or HMT alone did not change the granule morphology and crystalline type, but reduced the crystallinity and molecular weight and increased the resistant starch content. HMT alone had no significant effect on the solubility of starch, while EBI led to a considerable increase in the solubility of maize starch. The combined treatment of EBI and HMT aggravated apparent viscosity reduction, and the HMT starch pretreated with EBI had a smaller molecular weight and lower viscosity. In contrast, post-EBI samples had higher solubility and RS content. Primarily, it has excellent potential for producing low-viscosity and high-solubility starch foods.

Formation mechanism of starch nanocrystals from waxy rice starch and their separation by differential centrifugation

Starch nanocrystals (SNCs) were prepared from waxy rice starch via sulfuric acid hydrolysis. The objective focused on the following: i) the hydrolysis kinetics and structural properties of SNCs; ii) the effects of differential centrifugation on the yield and size distribution of SNCs. The hydrolysis was divided into a rapid hydrolysis stage in the initial two days and a slow hydrolysis stage after two days. During the two-day hydrolysis, the average diameter of SNCs reached 244 nm. After two days of hydrolysis, the degree of crystallinity, crystallite size, and melting temperature and enthalpy increased. The proportion of A-branched chains decreased, whereas the proportion of B1-branched chains and molecular weight did not change considerably. Thus, the reaction in the slow hydrolysis stage could be considered as the surface modification and gradual release of SNCs. Furthermore, SNCs with a small size and high charge density could be used for differential centrifugation.

Comparative investigation of the effects of electron beam and X-ray irradiation on potato starch: Structure and functional properties

Electron beam (particle radiation) and X-ray (electromagnetic radiation) without radioisotope in the application of material modification have received increasing attention in the last decade. To clarify the effect of electron beam and X-ray on the morphology, crystalline structure and functional properties of starch, potato starch was irradiated using electron beam and X-ray at 2, 5, 10, 20 and 30 kGy, respectively. Electron beam and X-ray treatment increased the amylose content of starch. The surface morphology of starch did not change at lower doses (< 5 kGy), but starch granules were aggregated with the increase of doses. All treatments decreased crystallinity, viscosity and swelling power but increased solubility and stability properties. The effects of electron beam and X-ray on the starch had a similar trend. Unlike X-ray, electron beam destructed the crystallinity of starch to a lesser extent, thereby increasing thermal stability and freeze-thaw stability. Furthermore, X-ray irradiation at higher doses (> 10 kGy) resulted in outstanding anti-retrogradation properties of starch compared with electron beam treatment. Thus, particle and electromagnetic irradiation displayed an excellent ability to modify starch with respective specific characteristics, which expands the potential application of these irradiations in the starch industry.

Formation of sweet potato starch nanoparticles by ultrasonic—assisted nanoprecipitation: Effect of cold plasma treatment

Starch nanoparticles (SNPs) were produced from sweet potato starches by ultrasonic treatment combined with rapid nanoprecipitation. The starch concentration, ultrasonic time, and the ratio of starch solution to ethanol were optimized through dynamic light scattering (DLS) technique to obtain SNPs with a Z-average size of 64.51 ± 0.15 nm, poly dispersity index (PDI) of 0.23 ± 0.01. However, after freeze drying, the SNPs showed varying degrees of aggregation depending on the particle size of SNPs before freeze-drying. The smaller the particle size, the more serious the aggregation. Therefore, we tried to treat SNPs with dielectric barrier discharge cold plasma before freeze drying. Properties including morphological features, crystalline structure and apparent viscosity of various starches were measured by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and rheometer, respectively. The results showed that, after cold plasma (CP) treatment, the aggregation of SNPs during freeze drying was significantly inhibited. Compared to the native sweet potato starch, SNPs showed a higher relative crystallinity and a lower apparent viscosity. After CP treatment, the relative crystallinity of CP SNPs was further higher, and the apparent viscosity was lower. This work provides new ideas for the preparation of SNPs and could promote the development of sweet potato SNPs in the field of active ingredient delivery.

Impacts of Cold Plasma Technology on Sensory, Nutritional and Safety Quality of Food: A Review

As an emerging non-thermal food processing technology, cold plasma (CP) technology has been widely applied in food preservation due to its high efficiency, greenness and lack of chemical residues. Recent studies have indicated that CP technology also has an impressing effect on improving food quality. This review summarized the impact of CP on the functional composition and quality characteristics of various food products. CP technology can prevent the growth of spoilage microorganisms while maintaining the physical and chemical properties of the food. It can maintain the color, flavor and texture of food. CP can cause changes in protein structure and function, lipid oxidation, vitamin and monosaccharide degradation, starch modification and the retention of phenolic substances. Additionally, it also degrades allergens and toxins in food. In this review, the effects of CP on organoleptic properties, nutrient content, safety performance for food and the factors that cause these changes were concluded. This review also highlights the current application limitations and future development directions of CP technology in the food industry. This review enables us to more comprehensively understand the impacts of CP technology on food quality and promotes the healthy application of CP technology in the food industry.

Lutein encapsulated in whey protein and citric acid potato starch ester: Construction and characterization of microcapsules

The poor water solubility and stability of lutein limit its application in industry. Microencapsulation technology is an excellent strategy to solve these problems. This study used citric acid esterified potato starch and whey protein as an emulsifier to prepare oil-in-water lutein emulsion, and microcapsules were constructed by spray drying technology. The effects of different component proportions on microcapsules' microstructure, physical and chemical properties, and storage stability were analyzed. Citrate esterified potato starch had good emulsifying properties, and when compounded with whey protein, the encapsulation efficiency (EE) of microcapsules increased, and the embedding effect of lutein improved. After microencapsulation, the solubility of lutein increased significantly, reaching over 49.71 %, and gradually raised with more whey protein content. Furthermore, the high proportion of whey protein helped improve microcapsules' EE and thermal properties, with the maximum EE reaching 89.36 %. The glass transition temperatures of microcapsules were all higher than room temperature, which indicated that they keep a stable state under general storage conditions. The experimental results of this study may provide a reference for applying lutein in food and other fields.