Morphological features and physicochemical properties of waxy wheat starch

Endosperm and amyloplast development in waxy wheat cultivars

The endosperm is an essential part of wheat grains, and the accumulation of amyloplasts in endosperm determines the quality of wheat. Because waxy wheat has a special starch quality, there is a need to understand differences in endosperm and starch morphologies among waxy wheat cultivars. This study investigated differences in the endosperm and amyloplasts of two near-isogenic lines (Shimai19-P and Shimai19-N) and the wheat cultivar Shimai19 during various growth stages using light microscopy and scanning electron microscopy. At 8 days after pollination (DAP), with endosperm development, the amyloplast distributions in the different endosperm regions of the three wheat varieties were in the following order: center of ventral endosperm > subaleurone of ventral endosperm > center of dorsal endosperm > modified aleurone > subaleurone of dorsal endosperm. At 16 DAP, small amyloplasts appeared in the endosperm cells in all three wheat cultivars; subsequently, endosperm cell development until maturity was more rapid in Shimai19-N than in the other varieties. This study revealed variations in amyloplast accumulation among endosperm regions and waxy wheat varieties during wheat grain development, which improved the understanding of nutrient accumulation and nutrient transfer of wheat grains.

Process optimization of wheat flour crisp puffing by radio frequency and the accompanying property changes of starch

This research performed the process optimization of wheat flour crisp puffing by radio frequency (RF) and investigated the accompanying property changes of starch. Experiments were performed in a 6 kW, 27.12 MHz pilot-scale RF system. The results showed that the volume expansion was highest (220%) when the conditions were employed as follows: electrode gap (115 mm); height of the sample (55 mm); initial moisture content of the sample (30%). Under these conditions, the samples were puffed at 120 s by RF, and changes in the starch properties were further observed. The results showed that the structure of the starch was destroyed, changing from oval and spherical in shape to fragmented. The crystal type of the starch changed from A to A + V types. Its crystal order was reduced, and the Fourier-infrared spectrum showed that the ratio of (1048/1022) cm-1 decreased from 1.142 to 1.047. The crystallinity decreased from 48.27% to 17.57%. These changes will help starch digestion and absorption in human body. These results indicated that RF puffing could become a potential development method for puffed snacks. PRACTICAL APPLICATION: In this study, the processes of radio frequency puffing wheat flour chips were optimized, and the changes of starch properties during puffing were studied. Therefore, this research provided a theoretical basis for the industrial application of radio frequency puffing.

Unsaponifiable Matter from Wheat Bran Cultivated in Korea Inhibits Hepatic Lipogenesis by Activating AMPK Pathway

Unsaponifiable matter (USM) from wheat bran, a by-product obtained from wheat milling, is abundant in health-promoting compounds such as phytosterols, tocopherols, policosanols, and alkylresorcinols. This study aimed to examine the effects of USM from the wheat bran of normal and waxy type wheat, Saekeumkang (SKK) and Shinmichal (SMC), on hepatic lipid accumulation in free fatty acid (FFA)-induced hepatocytes and to investigate the cellular mechanism. The total phytochemical contents were 46.562 g/100 g USM and 38.130 g/100 g USM from SKK and SMC, respectively. FFA treatment increased intracellular lipid accumulation by approximately 260% compared to the control group; however, treatment with USM from SKK and SMC significantly attenuated lipid accumulation in the hepatocytes in a dose-dependent manner. Moreover, USM downregulated the expression of lipogenic factors such as fatty acid synthase and sterol regulatory-element-binding protein 1c by approximately 40% compared to the FFA treatment group. Treatment with USM promoted lipolysis and positively regulated the expression of the proteins involved in β-oxidation, including peroxisome proliferator-activated receptor α and its downstream protein, carnitine palmitoyltransferase 1A. Moreover, the blockade of AMPK activation significantly abolished the inhibitory effects of USM on hepatic lipid accumulation. These results indicated that the USM from both SKK and SMC can alleviate lipid accumulation in hepatocytes in an AMPK-dependent manner. Therefore, USM from wheat bran may be useful as a therapeutic intervention for treating metabolic-dysfunction-associated fatty liver disease.

Comparative transcriptome analyses revealed key genes involved in high amylopectin biosynthesis in wheat

High amylopectin starch is an important modified starch for food processing industries. Despite a thorough understanding of starch biosynthesis pathway, the regulatory mechanism responsible for amylopectin biosynthesis is not well explored. The present study utilized transcriptome sequencing approach to understand the molecular basis of high amylopectin content in three high amylopectin mutant wheat lines ('TAC 6', 'TAC 358', and 'TAC 846') along with parent variety 'C 306'. Differential scanning calorimetry (DSC) of high amylopectin starch identified a high thermal transition temperature and scanning electron microscopy (SEM) revealed more spherical starch granules in mutant lines compared to parent variety. A set of 4455 differentially expressed genes (DEGs) were identified at two-fold compared to the parent variety in high amylopectin wheat mutants. At ten-fold, 279 genes, including two starch branching genes (SBEIIa and SBEIIb), were up-regulated and only 30 genes, including the starch debranching enzyme (DBE), were down-regulated. Among the genes, different isoforms of sucrose non-fermenting-1-related protein kinase-1 (TaSnRK1α2-3B and TaSnRK1α2-3D) and its regulatory subunit, sucrose non-fermenting-4 (SNF-4-2A, SNF-4-2B, and SNF-4-5D), were found to be highly up-regulated. Further, expression of the DEGs related to starch biosynthesis pathway and TaSnRK1α2 and SNF-4 was performed using qRT-PCR. High expression of TaSnRK1α2, SNF-4, and SBEII isoforms suggests their probable role in high amylopectin starch biosynthesis in grain endosperm.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03364-3.

The Potential of Traditional ‘Gaja’ and New Breed Lines of Waxy, Blue and Purple Wheat in Wholemeal Flour Fermentation

The aim of this study was to analyse and compare the acidity, microbiological and colour characteristics, fatty (FA) and amino (AA) acid profiles, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations, and macro- and microelement contents in non-treated (non-fermented) and fermented wholemeal cereal flours of ‘Gaja’ (traditional wheat) and new breed lines DS8888-3-6 (waxy wheat), DS8548-7 (blue wheat) and DS8535-2 (purple wheat). Independent fermentations were undertaken with selected strains of Pediococcus acidilactici, Liquorilactobacillus uvarum and Lactiplantibacillus plantarum. The results revealed that all the wholemeal cereal flours of the analysed wheat varieties are suitable for fermentation with the selected strains because all the fermented samples showed lactic acid bacteria (LAB) viable counts higher than 8.00 log10 CFU/g and desirable low pH values. In most of the cases, fermentation increased the concentration of essential amino acids in the wholemeal cereal samples, and the LAB strain used for fermentation proved to be a significant factor in all the essential amino acid content of wholemeal wheat (p ≤ 0.0001). When comparing the non-fermented samples, the highest GABA content was found in ‘Gaja’ and waxy wheat samples (2.47 µmol/g, on average), and, in all the cases, fermentation significantly increased GABA concentration in the wholemeal cereals. On the other hand, total levels of biogenic amines in wholemeal samples ranged from 22.7 to 416 mg/kg. The wheat variety was a significant factor in all the analysed macro- and microelement contents (p ≤ 0.0001) in the wholemeal cereals. Furthermore, fermentation showed to be a significant factor in most of the FA content of the wholemeal cereal samples. Finally, fermentation can also contribute to improving the biological and functional value of wholemeal wheat flours (by increasing essential amino acids and GABA concentrations); however, safety parameters (e.g., biogenic amines) also should be taken into consideration when optimizing the most appropriate technological parameters.

Analysis of starch structure and functional properties of tetraploid wheat (Triticum turgidum L.) with differing waxy protein composition

BACKGROUND

An increased demand for food has mirrored the increasing global population. Obesity and diabetes are two disorders induced by poor eating choices. Consequently, there is an urgent need to develop modified foods that can ameliorate such illnesses. The objective of this study was to explore the effect of Waxy genes on the structural and functional properties of starch, with the aim of improving food quality. Wild-type tetraploid wheat was compared with three mutants with different Waxy gene combinations.

RESULTS

The proportion of B-type granules was higher in the mutants than in the wild-type (Wx-AB), and there were significant changes in the starch granule size, number, and phenotype in the Wx free mutant (Wx-ab). The lowest branch chain length was observed in Wx-ab, whereas Wx-AB had the highest branch chain length of DP ≥ 37. Wx-ab had the highest degree of crystallinity. The crystallinity trend followed the order Wx-ab>Wx-Ab>Wx-aB>Wx-AB. The amount of slowly digestible starch (SDS) was higher in native, gelatinized, and retrograded starch in the mutant. The amount of retrograded starch was closer to gelatinized starch than to native starch.

CONCLUSION

Waxy proteins make a substantial contribution to starch structure. A lack of waxy proteins reduced the unit chains markedly compared with the control. Waxy proteins significantly affected the smaller and longer chains of starch. The lines with differing waxy composition had different effects on food digestion. The Wx-AB in native starch and Wx-Ab in gelatinized starch can control obesity and diabetes by slow-digesting carbohydrates and high resistance to digestion. © 2022 Society of Chemical Industry.

Study of Noodle Quality Based on Protein Properties of Three Wheat Varieties

Waxy wheat offers unique benefits in food processing, including improving the smoothness and performance of the product. However, waxy wheat is not yet commercially available. The protein characteristics, including the protein content, subunit distribution, secondary structure, chemical interactions, and microstructure of the gluten, were explored to realize the full potential of waxy wheat. The results showed that the noodles prepared from waxy wheat had a gentle and glutinous texture compared with GY2018 and YM13. Partial-waxy and waxy wheat had a lower gluten index and glutenin macropolymer (GMP) content than GY2018, indicating a reduced gluten strength. Confocal laser scanning microscopy (CLSM) images showed that the starch granules were not securely attached to the partial-waxy and waxy wheat protein matrix. In addition, the waxy protein chains appeared more elongated and they weakened the protein network. In particular, HMW-GS subunit 2 + 12 may be the essential cause of the weak dough from SKN1. Compared with GY2018 and YM13, SKN1 had the highest number of free sulfhydryl groups. Rather than ionic bonds, hydrophobic interactions increased the gluten network in GY2018, YM13, and SKN1. The weak molecular forces in the gluten will result in a soft noodle texture.

Rheological Properties of Wheat Flour Modified by Plasma-Activated Water and Heat Moisture Treatment and in vitro Digestibility of Steamed Bread

The study investigated the effects of plasma-activated water (PAW) and heat moisture treatment (HMT) on the rheological properties of wheat flour and the in vitro digestibility of steamed bread partially replaced by the modified wheat flour. After HMT, the gelatinization temperature of wheat flour increased and the gelatinization enthalpy reduced. The solubility and swelling power of wheat flour increased after the heat-moisture treatment. The solubility of modified flour after PAW-HMT treatment was lower than that of distilled water (DW)-HMT at the same temperature. The wheat flour with HMT had higher storage modulus (G') and loss modulus (G“), and had better ductility and deformability. Common wheat flour was partially replaced by modified flour to make steamed bread. The results indicated that the volume, height, diameter and specific volume of steamed bread were significantly decreased with the addition of HMT flour. However, the hardness, viscosity and chewiness increased significantly. The resistant starch content of steamed bread with the modified wheat flour increased. The results provide new insights for the development of new functional steamed bread.

A review of wheat starch analyses: Methods, techniques, structure and function

Wheat starch has received much attention as an important source of dietary energy for humans, an interesting carbohydrate and a polymeric material. The understanding of the structure and function of wheat starch has always been accompanied by newer technological tools. On the one hand, the general knowledge of wheat starch is constantly being enriched. On the other hand, an increasing number of studies are trying to add new insights to what is already known from two frontier perspectives, namely, wheat starch supramolecular structures and wheat starch fine structures (CLDs). This review describes the structure and function of wheat starch from the perspective of wheat starch analysis techniques (instruments).

Wheat Biocomposite Extraction, Structure, Properties and Characterization: A Review

Biocomposite materials create a huge opportunity for a healthy and safe environment by replacing artificial plastic and materials with natural ingredients in a variety of applications. Furniture, construction materials, insulation, and packaging, as well as medical devices, can all benefit from biocomposite materials. Wheat is one of the world’s most widely cultivated crops. Due to its mechanical and physical properties, wheat starch, gluten, and fiber are vital in the biopolymer industry. Glycerol as a plasticizer considerably increased the elongation and water vapor permeability of wheat films. Wheat fiber developed mechanical and thermal properties as a result of various matrices; wheat gluten is water insoluble, elastic, non-toxic, and biodegradable, making it useful in biocomposite materials. This study looked at the feasibility of using wheat plant components such as wheat, gluten, and fiber in the biocomposite material industry.

Effect of acetylated starch on the development of peanut skin-cassava starch foams

Cassava starch was modified by acetylation to obtain modified starches with a degree of substitution (DS) of 0.5 and 1.5. The acetylated cassava starches presented a reduction in temperature gelatinization and enthalpy, water solubility, and power swelling, in addition to a loss of crystallinity compared to native cassava starches. Acetylated cassava starch was used to the development of foams based on native cassava starch, 24% (w/w) of peanut skin, and 13% (w/w) of glycerol. It was used blends of native cassava starch and acetylated cassava starch with ratios of 100/0, 90/10, 80/20, 70/30, and 60/40. The foams containing acetylated cassava starch with DS = 0.5 exhibited a reduction in water absorption capacity (WAC) for water contact time of 30 min. Foams containing acetylated cassava starch with DS = 1.5 did not show a significant difference in WAC compared to foams made using only native cassava starch. The use of 30% (w/w) of acetylated cassava starch, independently of DS (0.5 or 1.5), resulted in faster degradation of foams than those without modified starches.

Effect of Controlled Hydrothermal Treatments on Mung Bean Starch Structure and Its Relationship with Digestibility

The changes in structure and digestion properties of mung bean starch due to hydrothermal treatment at various controlled temperatures were investigated. Results showed the increase in onset temperature (T_o) from 66.33 °C to 76.69 °C and decrease in enthalpies (∆H_g and ∆H_r) until the starch was completely gelatinized. The degree of molecular order (DMO) and degree of double helix (DDH) were significantly (p < 0.05) reduced from 1.35 to 1.01 and 1.38 to 0.98 respectively. X-ray diffraction (XRD) indicated the consecutive decrease in relative crystallinity (RC) while RVA analysis showed that peak and final viscosities were decreased significantly (p < 0.05). However, digestion kinetics indicated that degree of gelatinization increased the access of enzymes. As starch was partially gelatinized it yielded significantly lower glycemic index but no significant (p > 0.05) change in starch digestibility was observed after 70 °C. Hence, 70 °C can be considered as the critical hydrothermal treatment temperature in mung bean starch. Pearson's correlation analysis indicated that controlled hydrothermal treatment had negative effect on the DMO, DDH, RC and the granular damage increased vulnerability of mung bean starch to digestion. These findings gave insight into sequential changes in the structure and digestibility occurring during gelatinization process due to hydrothermal treatment. Controlled gelatinization in mung beans at 70 °C is useful and must be employed to produce the foods with lower starch digestibility.

Structural Orders of Wheat Starch Do Not Determine the In Vitro Enzymatic Digestibility

In this study, we elucidated the underlying mechanisms that are responsible for the rate-limiting step for wheat starch digestion. Wheat starch samples with a degree of gelatinization (DG) ranging from 0 to 100% were prepared. As DG increased, the ordered structures of the starch were disrupted increasingly. In contrast, almost all of the increase in the rate and extent of in vitro enzymatic digestion coincided with a DG of only 6% and a minor loss of structural order. As DG increased beyond 6%, digestibility of the starch increased only slightly. We propose that the access and binding of enzymes to starch is greatly increased with only a small DG, which is followed by the simultaneous hydrolysis of crystalline and amorphous areas in gelatinized starch. In vitro enzymatic digestibility of starch was determined predominantly by enzyme binding to starch rather than the ordered structures of starch.

Effects of Blends of Low-Protein Winter Wheat Flour and Barley Byproducts on Quality Changes in Noodles

The physicochemical characteristics of fresh noodles made with blends of low-protein wheat flour and barley byproduct (BBP, 250 μm) were investigated. The crude protein contents (PC) of flour from Goso and Backjoong cultivars were 7.91% and 7.67%, respectively. PC and β-glucan contents from the BBP were 14.10% and 3.11%, respectively, which were higher than those in wheat flour. The water-holding capacity (WHC) of various blends was increased as a function of BBP but not gluten contents. Goso flour had the highest starch content (78.68%), with peak and final viscosities of 3,099 and 3,563 cp, respectively. Peak and final viscosities, trough, breakdown, and setback of the blends were decreased with the addition of BBP. Noodles made with Backjoong had the highest thickness score, while the hardness of noodles made with blends of Goso or Backjoong and 20% BBP were similar to those made from wheat flour only. The WHC of the samples was strongly correlated with PC, crude fiber, and β-glucan. The PC was not correlated with final viscosity, setback, thickness, hardness, gumminess, or chewiness.

Technological characteristics of yeast-containing cakes production using waxy wheat flour

This article shows the feasibility of using waxy wheat flour, the starch of which doesn`t contain amylose, in order to stabilize the quality of yeast-containing cakes. The influence of the waxy wheat flour mass fraction and the stage of its adding on the physical, chemical and organoleptic characteristics of the products are studied. According to the technological properties of a new type of wheat flour, two methods of its adding are proposed ‒ adding the maximum amount of waxy wheat flour at dough kneading stage or using the mixture of waxy and bakery wheat flours for kneading sourdough and dough. It is shown that the replacement of 60 % bakery wheat flour with waxy wheat flour in the recipe of yeast-containing cakes at the dough kneading stage contributes to the production of products with higher quality and organoleptic characteristics compared to both the control and cakes based on a mixture of different types of wheat flour. These samples are characterized by increased by 1.7 – 11.3 % specific volume, porosity – 2.6 – 5.5 % and the total deformation of the crumb – 6.5 – 41.4 %.

Impact of acid and oxidative modifications, single or dual, of sorghum starch on biodegradable films

The objective of this study was to evaluate the effects of acid and oxidation modifications on sorghum starch, as well as the effect of dual modification of starch on the physical, morphological, mechanical, and barrier properties of biodegradable films. The acid modification was performed with 3% lactic acid and the oxidation was performed with 1.5% active chlorine. For dual modification, the acid modification was performed first, followed by oxidation under the same conditions as above. Both films of the oxidized starches, single and dual, had increased stiffness, providing a higher tensile strength and lower elongation when compared to films based on native and single acid modified starches. However, the dual modification increased the water vapor permeability of the films without changing their solubility. The increase in sorghum starch concentration in the filmogenic solution increased the thickness, water vapor permeability, and elongation of the films.

Phase Transition of Waxy and Normal Wheat Starch Granules during Gelatinization

The phase transition of waxy and normal wheat starches was systematically studied by light microscopy (LM) with a hot-stage, confocal laser scanning microscopy (CLSM) and differential scanning calorimetry (DSC). While being heated in water, waxy wheat starch showed a higher gelatinization enthalpy than that for the normal starch, which was also verified by the changes in birefringence. As confirmed by LM and CLSM, starch granules displayed an increased swelling degree with temperature increasing, and the gelatinization initially occurred at the hilum (botanical center) of the granules and then spread rapidly to the periphery. While the temperature range of birefringence was narrower than that of granule size change, the crystalline structure was melted at lower temperatures than those for the molecular orders. These results indicate that starch gelatinization was a complex process rather than a simple order-to-disorder granule transition.