Pasting Behavior of Amylose, Amylopectin and Their Mixtures as Determined by RVA Curves and First Derivatives

Genome-wide association study identifies loci and candidate genes for RVA parameters in wheat (Triticum aestivum L.)

The gelatinization and retrogradation characteristics of wheat starch affect the eating quality of Chinese-style food. Rapid Visco Analyzer (RVA) parameters have been widely used as important indicators to evaluate and improve the quality of wheat starch. However, the genetic basis of RVA parameters remains to be further explored. In the present study, a natural population was genotyped using 90K single nucleotide polymorphism (SNP) arrays, and the RVA parameters of this population grown in five environments were evaluated. The results showed that 22,068 high-quality SNP markers were identified and distributed unequally on the chromosomes. According to the genetic distance, 214 wheat materials were divided into four groups. Except for the pasting temperature (PTT), six parameters followed a normal distribution. Based on the general linear model, 969 significant association SNPs were detected by genome-wide association studies (GWAS), and chromosomes 7A and 2B had the most associated SNPs. Breakdown viscosity (BV) was associated with the most SNPs (n = 238), followed by PTT (n = 186), peak viscosity (PV; n = 156), trough viscosity (TV; n = 127), and final viscosity (FV; n = 126). According to the average linkage disequilibrium (LD), 33 stable quantitative trait loci (QTLs) were identified for single parameters in multiple environments, of which 12 were associated with BV, followed by peak time (PT; n = 8) and PTT (n = 7). On the other hand, 67 pleiotropic QTLs were identified for multiple parameters. Three candidate genes-TasbeIIa, TasbeI, and TassIIa-were screened for phenotyping analysis. The grain width and the weight of the TasbeIIa and TaSSIIa knockout (KO) lines were significantly lower than those of the TasbeI KO lines and the control (CK). The KO lines had smaller endosperm cells, smaller A-type starch granules, and higher amylose content. The TasbeI KO lines showed normal RVA curves, while the TasbeIIa KO lines showed flat curves. However, the TaSSIIa lines failed to paste under the RVA temperatures. Conclusively, the SNPs/QTLs significantly associated with the RVA parameters and genetic resources with novel haplotypes could be used to improve the quality of wheat starch.

Analysis of the impact of drying on common wheat quality and safety

Mycotoxin contamination in grain has been an ongoing concern in the world. Wheat, as a staple crop in China, is particularly notable for its mycotoxin contamination. The main mycotoxins in wheat include deoxynivalenol (DON) and its derivates, zearalenone (ZEN) and aflatoxin B1 (AFB1). After harvest, drying process is an effective technique and a necessary step to ensure the long-term safe storage of wheat. In this study, the moisture content, the concentrations of total fungi and main mycotoxins in post-harvest wheat of three wheat growing areas in the North China Plain were examined, and the effect of different drying methods on wheat quality was evaluated. The results showed that 87.5% of wheat samples were simultaneously contaminated with two or more mycotoxins. Due to the pre-harvest heavy rainfall, the moisture content, the levels of total fungi and mycotoxins in wheat samples of Liaocheng city were significantly higher compared to other regions. Moreover, the effects of different drying methods on the starch gelatinization and viscosity properties of wheat were investigated. The results showed that both natural air drying and dryer drying altered the crystal structure within starch particles and affected the gelatinization and viscosity properties of wheat starch. However, there is no significant difference between the wheat samples treated with two drying methods.

Structural, Thermal, Rheological, and Morphological Characterization of the Starches of Sweet and Bitter Native Potatoes Grown in the Andean Region

This study aimed to extract and characterize the morphological, physicochemical, thermal, and rheological properties of the starches of native potatoes grown in the department of Puno. Among the varieties evaluated were sweet native potato varieties Imilla Negra (Solanum tuberosum spp. Andígena), Imilla Blanca (Solanum tuberosum spp. Andígena), Peruanita, Albina or Lomo (Solanum chaucha), and Sutamari, and the bitter potatoes Rucki or Luki (Solanum juzepczukii Buk), Locka (Solanum curtilobum), Piñaza (Solanum curtilobum), and Ocucuri (Sola-num curtilobum), acquired from the National Institute of Agrarian Innovation (INIA-Puno). The proximal composition, amylose content, and morphological, thermal, and rheological properties that SEM, DSC, and a rheometer determined, respectively, were evaluated, and the data obtained were statistically analyzed using a completely randomized design and then a comparison of means using Tukey's LSD test. The results show a significant difference in the proximal composition (p ≤ 0.05) concerning moisture content, proteins, fat, ash, and carbohydrates. Thus, the amylose content was also determined, ranging from 23.60 ± 0.10 to 30.33 ± 0.15%. The size morphology of the granules is 13.09-47.73 µm; for the thermal and rheological properties of the different varieties of potato starch, it is shown that the gelatinization temperature is in a range of 57 to 62 °C and, for enthalpy, between 3 and 5 J/g.

Effect of Edible Coating Made from Arrowroot Flour and Kaffir Lime Leaf Essential Oil on the Quality Changes of Pork Sausage under Prolonged Refrigerated Storage

Edible coatings are pivotal in enhancing the quality of processed meat products, acting as barriers to environmental and microbial influences by adhering directly to the food surface. Arrowroot flour, a widely produced edible tuber in Thailand, is uncharted in terms of its capability and effectiveness as an edible coating on food materials. This study aims to elucidate the composition and spectral properties of arrowroot tuber flour (ATF) to discern its viability as an edible coating for pork sausages. ATF exhibited a composition predominantly featuring carbohydrates (74.78%), moisture (9.59%), and protein (8.89%), underlining its appropriateness as an edible coating. Rapid visco amylograph revealed ATF's significant pasting capability. This study incorporated kaffir lime leaves essential oil (KEO) into the ATF coating in diverse concentrations (0-3%). Fourier-transform Infrared spectroscopy illuminated characteristic peaks and bands, showing observable shifts with the integration of KEO, yet the majority of peak placements remained essentially unchanged. The microstructure of the coatings maintained its homogeneity at heightened KEO concentrations, reflecting compatibility with ATF. The efficacy of the ATF-KEO coatings was evaluated on pork sausages, using uncoated samples as controls. While color modifications were evident, coated sausages maintained consistent moisture content, water activity, and pH levels throughout the storage duration. The coated samples also manifested enhanced textural attributes and a decline in lipid oxidation, as evidenced by reduced TBARS levels compared to controls. A subsequent microbial examination corroborated the inhibitory capacity of the ATF-KEO coatings on the microbial proliferation in pork sausages, encapsulating Total Viable Count (TVC), psychrotrophic bacteria, and lactic acid bacteria. In conclusion, the findings substantiate the promising application of ATF, especially in synergy with KEO, as a proficient edible coating for meat products. This combination aids in preserving color and texture, impeding microbial advancement, and moderating lipid oxidation, thereby contributing to the overall quality and safety of the products.

High-amylose maize starch: Structure, properties, modifications and industrial applications

High-amylose maize refers to a special type of maize cultivar with a 50 %-90 % amylose content of the total starch. High-amylose maize starch (HAMS) is of interest because it possesses unique functionalities and provides many health benefits for humans. Therefore, many high-amylose maize varieties have been developed via mutation or transgenic breeding approaches. From the literature reviewed, the fine structure of HAMS is different from the waxy and normal corn starches, influencing its gelatinization, retrogradation, solubility, swelling power, freeze-thaw stability, transparency, pasting and rheological properties, and even in vitro digestion. HAMS has undergone physical, chemical, and enzymatical modifications to enhance its characteristics and thereby broaden its possible uses. HAMS has also been used for the benefit of increasing resistant starch levels in food products. This review summarizes the recent developments in our understanding of the extraction and chemical composition, structure, physicochemical properties, digestibility, modifications, and industrial applications of HAMS.

Impact of High Night Temperature on Yield and Pasting Properties of Flour in Early and Late-Maturing Wheat Genotypes

The inexorable process of climate change in terms of the rise in minimum (nighttime) temperature delineates its huge impact on crop plants. It can affect the yield and quality of various crops. We investigated the effect of high night temperature (HNT) (+2.3 °C over ambient) from booting to physiological maturity on the yield parameters, grain growth rate (GGR), starch content, composition, and flour rheological properties in early (HI 1544, HI 1563) and late-maturing (HD 2932) wheat genotypes. The change in yield under HNT was highly correlated with grain number per plant (r = 0.740 ***) and hundred-grain weight (r = 0.628 **), although the reduction in grain weight was not significantly different. This was also reflected as an insignificant change in starch content (except in HI 1544). Under HNT, late-sown genotypes (HI 1563 and HD 2932) maintained high GGR compared to the timely sown (HI 1544) genotype during the early period of grain growth (5 to 10 days after anthesis), which declined during the later phase of grain development. The increased rheological properties under HNT can be attributed to a significant reduction in the amylose to amylopectin (AMY/AMP) ratio in early-maturity genotypes (HI 1544 and HI 1563). The AMY/AMP ratio was positively correlated to flour rheological parameters (except setback from peak) under HNT. Our study reports the HNT-induced change in the amylose/amylopectin ratio in early maturing wheat genotypes, which determines the stability of flour starches for specific end-use products.

Fibrous Structures from Starch and Gluten

Starch is added to meat analogues for binding and water holding. In this study, we investigate whether starch can have an additional role as a structuring agent. Therefore, different types of starch were combined with wheat gluten at various amounts and sheared in a High Temperature Shear Cell to determine how starch influences the structuring behavior of gluten–starch blends. The starches were chosen based on their diverse amylose contents, leading to different technological properties. Remarkable differences were found between the starches investigated. The addition of Amioca starch (containing 1% amylose) had a strong negative influence on the ability of gluten to form fibers. Maize starch (25% amylose) and Hylon VII (68% amylose) formed fibrous materials up to high starch additions. The pre-gelatinizing of maize starch further increased the ability of gluten–starch mixtures to form fibrous structures. The influence of the different types of starch on the hardness, deformability, and stiffness of the sheared samples was also assessed, revealing a spectrum of achievable properties through the addition of starch. Most remarkable was the formation of a material with anisotropy in Young’s modules. This anisotropy is also found in chicken meat, but not in protein-based fibrous materials. Furthermore, it was observed that the pre-gelatinization of starch facilitated fiber formation. A similar effect of pre-gelatinizing the starch was found when using faba bean meal with added wheat gluten, where fibrous structures could even be formed in a recipe that previously failed to produce such structures without pre-treatment.

A structural study of the self-association of different starches in presence of bacterial cellulose fibrils

A multi-analytical study was performed to analyse the effect of bacterial cellulose (BCF) on the self-association of starches with different amylose content (wheat, waxy-maize), assessing macrostructural properties (rheology, gel strength) and some nano and sub-nano level features (small and wide-angle X-ray scattering). Although pasting viscosities and G' were significantly increased by BCF in both starches, cellulose did not seem to promote the self-association of amylose in short-range retrogradation. A less elastic structure was reflected by a 2-3-fold increase in loss factor (G″/G') at the highest BCF concentration tested. This behavior agreed with the nano and sub-nano characterisation of the samples, which showed loss of starch lamellarity and incomplete full recovery of an ordered structure after storage at 4 °C for 24 h. The gel strength data could be explained by the contribution of BCF to the mechanical response of the sample. The information gained in this work is relevant for tuning the structure of tailored starch-cellulose composites.

Potential interactions between starch and fruit pomace may impact the expansion ratio of direct expanded extrudates

Due to their dense characteristics, direct-expanded products fortified with insoluble fiber are generally not well accepted. Understanding the interactions between starch and fiber could help to effectively choose and modify ingredients to produce products containing high amounts of fiber. Therefore, this study aims to explain the interplay between two starches (native and waxy corn) and two pomace types (blueberry and cranberry). Blends up to 100% of pomace were extruded using a co-rotating twin-screw extruder. Raw material and milled extrudates were analyzed for their pasting and hydration properties. Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy were conducted to observe molecular changes. The expansion ratio (ER) significantly decreased as pomace was added and ranged from 3.85 for pure waxy corn starch to approximately 1 for blends that contained 80% pomace. Distinctions between the blends were observed. Particularly, at 20% of pomace inclusion, native corn starch with cranberry pomace showed a significantly higher ER. Different behaviors were also detected during the physicochemical analyses. A nonlinear trend between pomace level and water solubility as well as absorption was observed for native corn starch blends, suggesting that molecular interactions between the biopolymers occur. FTIR and NMR results give no evidence for new covalent bonds; hence, the most likely interactions occurring are hydrogen bonds. In addition to the dilution effect of pomace addition, the enhancement or weakening of such interactions between starch molecules by pomace compounds may reduce the ER.

CRISPR/Cas9-Mediated Mutagenesis of the Granule-Bound Starch Synthase Gene in the Potato Variety Yukon Gold to Obtain Amylose-Free Starch in Tubers

Potato (Solanum tuberosum L.) is the third most important food crop after rice and wheat. Its tubers are a rich source of dietary carbohydrates in the form of starch, which has many industrial applications. Starch is composed of two polysaccharides, amylose and amylopectin, and their ratios determine different properties and functionalities. Potato varieties with higher amylopectin have many food processing and industrial applications. Using Agrobacterium-mediated transformation, we delivered Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) reagents to potato (variety Yukon Gold) cells to disrupt the granule-bound starch synthase (gbssI) gene with the aim of eliminating the amylose component of starch. Lugol-Iodine staining of the tubers showed a reduction or complete elimination of amylose in some of the edited events. These results were further confirmed by the perchloric acid and enzymatic methods. One event (T2-7) showed mutations in all four gbss alleles and total elimination of amylose from the tubers. Viscosity profiles of the tuber starch from six different knockout events were determined using a Rapid Visco Analyzer (RVA), and the values reflected the amylopectin/amylose ratio. Follow-up studies will focus on eliminating the CRISPR components from the events and on evaluating the potential of clones with various amylose/amylopectin ratios for food processing and other industrial applications.

Highly branched amylopectin binder for sulfur cathodes with enhanced performance and longevity

The sulfur cathode of lithium-sulfur (Li-S) batteries suffers from inherent problems of insufficient mechanical strength and the dissolution of sulfur and polysulfides. Inspired by the extraordinarily resilient and strong binding force of the Great Wall binder, that is, the sticky rice mortar, we extracted highly branched amylopectin (HBA), the effective ingredient, as a low-cost, nontoxic and environmentally benign aqueous binder for the sulfur cathode. The HBA-based cells outperform the Li-S batteries based on the traditional polyvinyldene diflouride (PVDF) binder and a lowly branched polysaccharide binder. The improved electrochemical performance in the HBA-based cell could be attributed to two mechanisms. First, the branched structure of the HBA provides enhanced mechanical and adhesive properties, which allow for a robust electronic and ionic conductive framework to be maintained throughout the cathode after extended cycling. Second, the HBA shows enhanced polysulfide retention due to the polymer's abundant lone-pair rich hydroxyl groups and the formation of C─S bonds between the HBA and polysulfides prohibits the shuttle effect of polysulfides. The improved mechanical properties and polysulfide retention function of the HBA binder facilitate the HBA-based Li-S battery to deliver a long cycle life of 500 cycles at 2 C while only displaying a capacity fading of 0.104% per cycle.

Comparative assessment of nutritional, thermal, rheological and functional properties of nine Australian lupin cultivars

Lupin holds an important place among the legumes and the utilization of lupin as a dietary protein source is an excellent environmentally friendly alternative to animal-based products for human nutrition. In the present study, nutritional, thermal, rheological and functional properties of nine Australian lupin cultivars have been assayed in order to find the most valuable one, both nutritiously and industrially. The set comprised six Lupinus angustifolius L. viz., Barlock, Gunyadi, Jenabillup, Jindalee, Jurien, Mandelup and three Lupinus albus L. viz., Luxor, Rosetta, WK388 cultivars. The tests included analysis of color, macronutrient and micronutrient composition, pasting, textural and thermal properties, electrophoretic profile of protein isolates, swelling power, water and oil absorption capacity, emulsifying capacity, emulsion stability, creaming stability, foaming capacity and stability of the cultivars’ dehulled seed flours. The results indicated substantial variation in macro and micro-nutritional value as well as satisfactory swelling ability, solubility, surface hydrophobicity, foaming ability, emulsifying capacity and gelation property of lupin flours. Superior nutritional, thermal, rheological and functional potential was demonstrated by the L. albus cultivars compared to the L. angustifolius cultivars with the exception of Mandelup.

Engineering Properties of Sweet Potato Starch for Industrial Applications by Biotechnological Techniques including Genome Editing

Sweet potato (Ipomoea batatas) is one of the largest food crops in the world. Due to its abundance of starch, sweet potato is a valuable ingredient in food derivatives, dietary supplements, and industrial raw materials. In addition, due to its ability to adapt to a wide range of harsh climate and soil conditions, sweet potato is a crop that copes well with the environmental stresses caused by climate change. However, due to the complexity of the sweet potato genome and the long breeding cycle, our ability to modify sweet potato starch is limited. In this review, we cover the recent development in sweet potato breeding, understanding of starch properties, and the progress in sweet potato genomics. We describe the applicational values of sweet potato starch in food, industrial products, and biofuel, in addition to the effects of starch properties in different industrial applications. We also explore the possibility of manipulating starch properties through biotechnological means, such as the CRISPR/Cas-based genome editing. The ability to target the genome with precision provides new opportunities for reducing breeding time, increasing yield, and optimizing the starch properties of sweet potatoes.

Dielectric barrier atmospheric cold plasma applied to the modification of Ariá (Goeppertia allouia) starch: Effect of plasma generation voltage

The goal of this paper was to evaluate the influence of a range of plasma generation voltages on the physicochemical, structural, and technological properties of Aria (Goeppertia allouia) starch. Untreated (0 kV) and high voltages of cold plasma generation (7, 10, 14, and 20 kV) treated samples were evaluated according to their amylose content, pH, groups carbonyl/carboxyl, molecular size distribution, structure and technological properties (empirical viscosity, hydration properties, thermal analysis and gel strength). The applied voltage of 14 kV resulted in the greatest depolymerization of the starch chains, while 20 kV allowed the formation of oxidized complexes, promoting crosslinking of the starches chain. The cold plasma technique did not affect the levels of resistant starches, but increased the starch digestibility. The increased carbonyl and carboxyl groups also influenced the paste viscosity, improved hydration properties. This study suggests that the cold plasma technique can be useful in the controlled modification of starches, producing starches with different technological properties.

Clean label starch: production, physicochemical characteristics, and industrial applications

Recently, health-conscious consumers have a tendency to avoid the use of modified starch in their food products because of reluctance regarding food additives or chemical processes. The present paper considers the characteristics and manufacturing methods of clean label starch, which is free from chemical modification. Clean label starch manufacturing is mainly dependent on starch blending, physical and enzymatic modification methods. Physical modifications include ultrasound, hydrothermal (e.g., heat-moisture treatment and annealing), pre-gelatinization (e.g., drum drying, roll drying, spray cooking, and extrusion cooking), high-pressure (high hydrostatic pressure), and pulsed electric field treatments. These physical processes allow variation of starch properties, such as morphological, thermal, rheological, and pasting properties. Enzyme treatment can change the properties of starch more dramatically. Actual use of clean label starch with such altered properties has occurred in industry and is described here. This review may provide useful information on the current status and future direction of clean label starch in the field of food science.

Investigating the potential of slow-retrograding starches to reduce staling in soft savory bread and sweet cake model systems

The potential anti-staling property of starches with slow-retrograding amylopectin was studied in soft wheat bread and cake model systems. Normal rice, waxy rice, and wheat starches were processed by drum drying or extrusion, and native starch was used as a comparator. Extrusion processing causing amylopectin fragmentation can reduce intermolecular retrogradation of rice starch. Starches were incorporated into model breads and cakes as partial replacements for flour on a dry weight basis (3 and 6% for cakes, 5 and 15% for breads). Starches pregelatinized by extrusion had moderate molecular fragmentation, as indicated by RVA and HPSEC-MALLS-RI. Starches previously shown to have lower intermolecular retrograding amylopectin (normal rice, waxy rice) resulted in minor to moderate reductions in hardness and other textural properties as indicated by texture profile analysis (TPA) in breads and cakes upon storage for up to 12 wk. A higher degree of starch fragmentation is suggested to produce lower staling. Incorporation of normal and waxy rice starches resulted in softer breads and cakes than wheat starch, which could be attributed to the shorter external and internal amylopectin chains of rice starch. Higher inclusion (15%) of slow-retrograding waxy rice in the bread model system showed the most potential for anti-staling property.

Pearl millet (Pennisetum glaucum) couscous breaks down faster than wheat couscous in the Human Gastric Simulator, though has slower starch hydrolysis

Pearl millet couscous broke down into smaller, more numerous particles that had slower starch hydrolysis compared to wheat couscous.

Textural and physical properties of retort processed rice noodles: Influence of chilling and partial substitution of rice flour with pregelatinized high-amylose maize starch

This study investigated the influence of pregelatinized high-amylose maize starch and chilling treatment on the physical and textural properties of canned rice noodles thermally processed in a retort. Rice noodles were prepared from rice flour partially substituted with pregelatinized high-amylose maize starch (Hylon VII™) in the ratios 0, 5, 10, and 15% (wt/wt). High-amylose maize starch improved the texture and brightness of fresh (not retorted) noodles. Chilling treatment led to significant (P ≤ 0.05) improvement in the texture of fresh noodles at all levels of substitution with high-amylose starch. The highest hardness was recorded at 15% amylose level in chilled nonretorted noodles. Retort processing induced a major loss of quality through water absorption, retort cooking loss, decreased noodle hardness, and lightness. However, the results showed that amylose and chilling treatment positively reduced the impact of retorting. For each level of amylose substitution, a low retort cooking loss and increased noodle hardness were associated with a chilling treatment. For both chilled and nonchilled noodles, retort cooking loss and hardness increased with increasing levels of amylose substitution.

A new GH13 α-glucosidase from alkaliphilic Bacillus pseudofirmus 703 with both exo-α-l, 4-glucosidase and oligo-l, 6-glucosidase activities toward amylopectin

Debranching of (1, 6)-α-linkages in starch is of great significance as it is widely used in different industries. In recent years, identifying a single potential enzyme that could debranch (1, 6)-α-linkages and cleave (1, 4)-α-linkages brought great interest as amylopectin possessed both (1, 4)-α- and (1, 6)-α-linkages. In the present study, a 64\,kDa exo-α-l, 4-glucosidase from Bacillus pseudofirmus 703, annotated as Amy112, was cloned and characterized. Biochemical analysis indicated that heterologous Amy112 expressed in Escherichia coli exhibited a high activity against amylopectin, with the optimal temperature and pH of 40°C and pH 7.0, respectively. Addition of K⁺ ions improved the amy112 activity by 12%, but Li⁺, Ca²⁺ and Mg²⁺ ions showed no significant effect. Amy112 sequence homology revealed that it belonged to glycoside hydrolase family 13, showing 65% identity with α-glucosidase GSJ from Geobacillus sp. HTA-462. This is the first report indicating that Amy112 from B. pseudofirmus 703 belongs to GH13 enzyme family, having both exo-α-1, 4-glucosidase and oligo-l, 6-glucosidase activities. However, no transglycosylation activity was detected in LC-MS analysis. Amy112 would be of great significance of being utilized to debranch starch in different industries in a cost effective manner.