Behaviors of large A-type and small B-type wheat starch granules esterified by conventional and pulsed electric fields assisted methods

Butyryl group distribution modulates the structure and properties of butyrylated maize starch focused on amylose contents

In this study, four types of maize starch with different amylose contents (3 %, 25 %, 40 %, and 70 %) were used to prepare butyrylated starches. Based on amylose contents, the influence of butyryl group distribution on the structure, thermal and digestive properties of butyrylated maize starch was investigated. The butyrylation reaction mainly substituted butyryl groups on amylose, and the butyryl groups were most easily substituted for the hydroxyl group at the C6 position. The degree of substitution of butyrylated starch reached its maximum when the amylose content was 40 %, and the degree of substitution did not correlate linearly with the amylose content. The butyrylation reaction increased the surface roughness, decreased the crystallinity, enthalpy value and molecular weight of native starch granules, resulting in a decrease in the degree of internal order of the starch and inducing the rearrangement of the amylose molecular chains in the amorphous region of the starch. The combination of the amylose content and the substitution of butyryl groups on amylose affected the digestibility of starch and ultimately increased its resistance. The Pearson correlation coefficient further confirmed the correlation between the distribution of butyryl groups and the structure and properties of butyrylated starch.

Functionalization Methods of Starch and Its Derivatives: From Old Limitations to New Possibilities

It has long been known that starch as a raw material is of strategic importance for meeting primarily the nutritional needs of people around the world. Year by year, the demand not only for traditional but also for functional food based on starch and its derivatives is growing. Problems with the availability of petrochemical raw materials, as well as environmental problems with the recycling of post-production waste, make non-food industries also increasingly interested in this biopolymer. Its supporters will point out countless advantages such as wide availability, renewability, and biodegradability. Opponents, in turn, will argue that they will not balance the problems with its processing and storage and poor functional properties. Hence, the race to find new methods to improve starch properties towards multifunctionality is still ongoing. For these reasons, in the presented review, referring to the structure and physicochemical properties of starch, attempts were made to highlight not only the current limitations in its processing but also new possibilities. Attention was paid to progress in the non-selective and selective functionalization of starch to obtain materials with the greatest application potential in the food (resistant starch, dextrins, and maltodextrins) and/or in the non-food industries (hydrophobic and oxidized starch).

Effect of Pulsed Electric Field Treatment on the Protein, Digestibility, and Physicochemical Properties of Starch Granules in Wheat Flour

The effect of pulsed electric field (PEF) treatment depends mainly on the electric field strength and treatment time. In this study, wheat flour-water suspensions were treated with PEF at an electric field strength of 3 kV/cm for 0 to 1400 pulses to obtain a specific energy input of 0 to 656 kJ/kg. The effect of PEF on the removal or unfolding of proteins from the starch surface, digestibility, starch granule structure, and physicochemical properties of wheat flour was studied. The removal of proteins from the surface and the damage to the internal structure of wheat starch granules after PEF treatment was detected by confocal laser scanning microscopy (CLSM) and FTIR. The damage of the PEF-treated wheat starch granules was observed by scanning electron microscopy (SEM). From CLSM results, penetration of dextran (Mw 10,000 Da) into starch granules of wheat flour was dependent on the energy input of PEF. The high the energy input showed the intense penetration of the biopolymer. The benefits of the accessibility of biopolymer in starch granules are to increase enzyme digestion, especially rapidly digestible starch (RDS). The RDS of wheat flour treated with PEF at 656 kJ/kg was 41.72%, whereas the RDS of wheat flour control was 27.59%.

Preparation, multi-scale structures, and functionalities of acetylated starch: An updated review

Acetylated starch has been widely used as food additives. However, there was limited information available regarding the impact of acetylation on starch structure and functionalities, as well as the advanced acetylation technologies. This review aimed to summarize current methods for starch acetylation and discuss the structure and functionalities of acetylated starch. Innovative techniques, such as milling, microwave, pulsed electric fields, ultrasonic, and extrusion, could be employed for environmental-friendly synthesis of acetylated starch. Acetylation led to the degradation of starch structures and weakening of the interactions between starch molecules, resulting in the disorganization of starch multi-scale ordered structure. The introduction of acetyl groups retarded the self-reassembly behavior of starch, leading to increased solubility, clarity, and softness of starch-based hydrogels. Moreover, the acetyl groups improved water/oil absorption capacity, emulsifiability, film-forming properties, and colonic fermentability of starch, while reduced the susceptibility of starch molecules to enzymes. Importantly, starch functionalities were largely influenced by the decoration of acetyl groups on starch molecules, while the impact of multi-scale ordered structures on starch physicochemical properties was relatively minor. These findings will aid in the design of structured acetylated starch with desirable functionalities.

Starch granules and their size distribution in wheat: Biosynthesis, physicochemical properties and their effect on flour-based food systems

Starch is a vital component of wheat grain and flour, characterized by two distinct granule types: A-type starch (AS) with granules larger than 10 µm in diameter, and B-type starch (BS) with granules measuring no more than 10 µm in diameter. This review comprehensively evaluates the isolation, purification, and biosynthesis processes of these types of granules. In addition, a comparative analysis of the structure and properties of AS and BS is presented, encompassing chemical composition, molecular, crystalline and morphological structures, gelatinization, pasting and digestive properties. The variation in size distribution of granules leads to differences in physicochemical properties of starch, influencing the formation of polymeric proteins, secondary and micro-structures of gluten, chemical and physical interactions between gluten and starch, and water absorption and water status in dough system. Thus, starch size distribution affects the quality of dough and final products. In this review, we summarize the up-to-date knowledge of AS and BS, and propose the possible strategies to enhance wheat yield and quality through coordinated breeding efforts. This review serves as a valuable reference for future advancements in wheat breeding.

The effects of pulsed electric fields treatment on the structure and physicochemical properties of dialdehyde starch

The structural and physicochemical properties changes of corn starch oxidized by sodium periodate under the assistance of pulsed electric fields (PEF) were studied. It was found that dialdehyde starch (DAS) particles produced by PEF-assisted oxidation exhibited shrinkage and pits, and had a larger particle size when compared to the control without PEF. The solubility of the DAS (12 kV/cm PEF- assisted oxidation) improved by 70.2% when compared to the native starch. Increment in the strength of the PEF, led to a decrease in the viscosity of the DAS. In addition, the aldehyde group content of the DAS produced by PEF-assisted oxidation exhibited shrinkage and pits, and had a larger particle size when compared to the control increased by 11.6% when compared with the traditional oxidation method. PEF is an effective method to promote oxidation reaction of starch.

The microstructure and thermal properties of pulsed electric field pretreated oxidized starch

The structure and thermal properties of pulsed electric field (PEF) assisted sodium hypochlorite oxidized starch were investigated. The carboxyl content of the oxidized starch was increased by 25 % when compared with the traditional oxidation method. Dents and cracks were evident on the surface of the PEF-pretreated starch. Compared with native starch, the peak gelatinization temperature (T_p) of PEF-assisted oxidized starch (POS) was reduced by 10.3 °C, while that of the oxidized starch without PEF treatment (NOS) was only reduced by 7.4 °C. In addition, PEF treatment further reduces the viscosity and improve the thermal stability of the starch slurry. Therefore, PEF treatment combined with hypochlorite oxidation is an effective method to prepare oxidized starch. PEF showed great potential in expanding starch modification, to promote a wider application of oxidized starch in the paper, the textile and the food industry.

Starch propionylation acts as novel encapsulant for probiotic bacteria: A structural and functional analysis

Propionylated potato starch (PPS) with different degrees of substitution (DS) was prepared from native potato starch (NPS) and their potential to encapsulate Lactobacillus rhamnosus GG (LGG) was analyzed. Fourier transform infrared spectroscopy (FTIR) showed a characteristic peak of propionyl groups, which appeared at 1746 cm^-1, demonstrating that propionylation occurred. X-ray diffraction (XRD) results revealed that the characteristic diffraction peak intensity of PPS gradually disappeared with the increasing of the DS, which was related to the loss of the ordered crystalline structure of starch granules. Propionylation resulted in the starch to be more thermally stable than its native starch. Furthermore, the propionylated starch had a higher resistance to digestion and hydrophobicity. More importantly, the micro-capsulated LGG derived from propionylated starch could achieve a maximum embedding efficiency of 87.77% at starch DS = 1.54, and also demonstrated a higher resistance to a strong acidic condition and a greater storage stability at 4 °C. This study may highlight a novel approach for probiotic encapsulation using propionylated potato starch as an encapsulant.

Effect of different starch acetates on the quality characteristics of frozen cooked noodles

The physicochemical properties of starch acetates with an equal degree of substitution prepared from pea, corn, and wheat starch and their effects on frozen cooked noodle (FCN) quality were investigated. The result showed that the three kinds of starch acetates had different effects on the quality of FCN due to their different blue values, freeze-thaw stability, and crystalline morphology analyzed by XRD (p < .05). The FCN with the addition of 20% CAS exhibited slow deterioration of textural properties during holding for 30 min. The analysis of the changes in the content of free SH group and glutenin macropolymer (GMP) demonstrated that the addition of CAS promoted protein disulfide cross-linking and decreased protein mobility during holding. Fourier transform infrared spectroscopy (FT-IR) revealed that FCN with the addition of CAS had low decrement in α-helix and β-sheet during holding, indicating that starch acetates contributed to the maintenance of the gluten network structure.

Effect of moist and dry-heat treatment processes on the structure, physicochemical properties, and in vitro digestibility of wheat starch-lauric acid complexes

Herein, we investigated the impact of moist (steaming and boiling) and dry (baking and microwaving)-heat treatment processes on the structure and physicochemical properties of wheat starch (WS) supplemented with lauric acid (LA). Elemental composition analysis revealed the interplay between WS and LA. Scanning electron microscopy (SEM) and iodine staining revealed that lamellar crystalline structure of WS-LA complexes was improved after moist-heat treatment (relative to samples without any heat treatments); the finding which is at variance to dry-heat treatment process. Additionally, high resistance to thermal decomposition and a lower 1022/995 cm^-1 absorbance ratio were observed in moist-heat treated WS-LA compared with dry-heat samples. Moreover, the V-type diffraction peak intensity and resistance to in vitro enzymatic hydrolysis of samples treated with moist-heat were increased to a greater extent than the dry-heat treated counterparts. In sum, this study would facilitate the application of functional starch-lipid complexes in food necessitated heat treatments.

Recent advances in heat-moisture modified cereal starch: Structure, functionality and its applications in starchy food systems

Cereals, one of the starch sources, have a tremendous and steady production worldwide. Starchy foods constitute the major part of daily calorie intake for humans. As a simple and green modification approach, heat-moisture treatment (HMT) could change the granular surface characteristics and size, crystalline and helical structure, as well as molecular organization of cereal starch. The changing degree is contingent on HMT parameters and botanical origin. Based on the hierarchical structure, this paper reviews functionalities of heat-moisture modified cereal starch (HMCS) reported in latest years. The functionality of HMCS could be affected by co-existing non-starch ingredients through non-covalent/covalent interactions, depolymerization or simply attachment/encapsulation. Besides, it summarizes the modulation of HMCS in dough rheology and final food products' quality. Selecting proper HMT conditions is crucial for achieving nutritious products with desirable sensory and storage quality. This review gives a systematic understanding about HMCS for the better utilization in food industry.

Review of the application of pulsed electric fields (PEF) technology for food processing in China

With the improvement of living standards, growing consumer demand for high-quality and natural foods has led to the development of new mild processes to enhance or replace conventional thermal and chemical methods for food processing. Pulsed electric fields (PEF) is an emerging and promising non-thermal food processing technology, which is ongoing from laboratory and pilot plant level to the industrial level. Chinese researchers have made tremendous advances in the potential applications of PEF for processing a wide range of food commodities over the last few years, which contributes to the current understanding and development of PEF technology. The objective of this paper is to conduct a systematic review on the achievements of PEF technology used for food processing in China and the corresponding processing principles. Research on the applicability of PEF in food processing suggests that PEF can be used alone or in combination with other methods, not only to inactivate microorganisms and extract active constituents, but also to modify biomacromolecules, enhance chemical reactions and accelerate the aging of fermented foods, which are mainly related to permeabilization of biomembranes, occurrence of electrochemical and electrolytic reactions, polarization and realignment of molecules, and reduction of activation energy of chemical reactions induced by PEF treatments. In addition, some of the most important challenges for the successful implementation of large-scale industrial applications of PEF technology in the food industry are discussed. The results bring out the benefits of both researchers and the industry.