Rice Starch Diversity: Effects on Structural, Morphological, Thermal, and Physicochemical Properties-A Review

Enhancing functional properties of rice starches through hydroxypropylation for development of reduced-fat white sauces

Present study investigated the preparation of commonly used white sauce with 50 % less added fat by using 10 % hydroypropylated Irri and Basmati rice starches in the formulation. The sauces incorporated with hydroxypropylated starches exhibited significantly lower gelatinization temperature and time, while the change in maximum viscosity was insignificant. Significantly improved stability at ambient, refrigeration, and freezing temperatures of reduced-fat white sauces was observed whereas change in the taste was insignificant. Basmati hydroxypropylated starch containing white sauce significantly mimicked the sensory properties of full-fat sauces. The hydroxypropyl groups were found to be 1.06 % and 1.16 % for Basmati and Irri hydroxypropylated starches, respectively. These values fall below the specified limit set by the Food and Drug Administration for the food grade hydroxypropylated starches. Significant improvements in peak viscosity, swelling power, solubility, percent transmittance, and water retention capacity were observed after the chemical modification of both rice varieties.

Appearance, components, pasting, and thermal characteristics of chalky grains of rice varieties with varying protein content

This study investigated two rice varieties, GuichaoII and Jiazao311, with distinct protein content to determine the variation in appearance, components, pasting, and thermal properties of rice with different chalkiness degrees. Grain length, width, head rice weight, and whiteness of both varieties markedly increased as chalkiness increased from 0% to 50%. However, the variation in components, pasting, and thermal characteristics of chalky grain substantially differed between the rice varieties. The protein content of GuichaoII (low protein content) significantly increased with the chalkiness degree, along with a significant increase in onset, peak, and conclusion temperatures and gelatinization enthalpy. In Jiazao311 (high protein content), the chalkiness degree increased with the protein content but decreased with the starch content, along with increased trough, final, setback, and consistency viscosities. Compared to amylose content, protein content had a greater influence on the thermal properties and pasting characteristics of chalky grains of GuichaoII and Jiazao311, respectively.

Relationship between Chalkiness and the Structural and Physicochemical Properties of Rice Starch at Different Nighttime Temperatures during the Early Grain-Filling Stage

The chalkiness, starch fine structure, and physiochemical properties of rice starch were analyzed and their correlations were investigated under different nighttime temperatures during the early grain-filling stage. Compared to MT, medium temperature (MT) and low (LNT) and high (HNT) nighttime temperatures resulted in an increased chalky grain rate (CGR) and chalkiness degree (CD). LNT mainly affected the chalkiness by increasing peak1 (short branch chains of amylopectin), the branching degree, and the proportion of small starch granules but decreasing peak2 (long branch chains of amylopectin) and peak3 (amylose branches). This altered the pasting properties, such as by increasing the peak viscosity and final viscosity. However, HNT mainly affected the chalkiness by increasing peak2 and the crystallinity degree but decreasing peak1 and peak3. Regarding the thermal properties, HNT also elevated peak and conclusion temperatures. The CGR and CD were significantly and positively correlated with the proportions of small and medium starch granules, peak1, branching degree, gelatinization enthalpy, setback viscosity, and pasting time but markedly and negatively correlated with the proportion of large starch granules, amylose content, peak3, peak viscosity, and breakdown viscosity. These findings suggest that LNT and HNT disrupted the starch structure, resulting in increased chalkiness. However, their mechanisms of action differ.

Hot air-assisted radio frequency drying of corn kernels: the effect on structure and functionality properties of corn starch

Hot air (HA) drying caused quality damage of grains with long treatment time. Radio frequency (RF) heating as an emerging technology was applied to improve drying quality of cereals effectively. The effects of HA-RF drying (50 °C, 70 °C, 90 °C) of corn kernels on the morphology, structure, and physicochemical properties of starch were investigated and compared with HA drying. The surface of treated starch became rough, along with fragments and pores. Drying treatments increased the amylose content from 10.59 % to 23.88 % and the residual protein content of starch from 0.58 % to 1.23 %, and reduced the crystallinity from 31.95 % to 17.15 % and short-range order structures of starch from 0.918 to 0.868. The change of structures in turn resulted in the increase of pasting viscosity, gelatinization temperature, storage modulus and loss modulus. Furthermore, the HA-RF dried starch displayed stronger thermal stability, higher gelatinization degree and better gelation properties than the HA-treated starch at the same temperature. The data proved that the synergistic effects of HA and RF were more effective in modulating the starch structure and improving the functional characteristics of corn starch. This paper would like to provide potential reference for better application of HA-RF technologies to corn.

Improvement of sorghum-wheat blended flours by E-beam irradiation: Physicochemical properties, rheological behavior, microstructure, and quality properties

To enhance the processing suitability of blended flours, this study used 4 kGy E-beam irradiated (EBI) sorghum flour in different ratios blended with wheat flour and further verified the improvement mechanism of the processed products under the optimal ratios. The results suggested that the EBI can mitigate the deterioration of the blend flour farinograph properties while enhancing the gas release during dough fermentation. Under the same addition ratio, the irradiated blend flours showed higher expansion height, gas release, cavitation time, and gas retention coefficient than the control flours. Also, irradiated blend flours retained a gluten network at a higher addition rate (20 %). Moreover, the irradiated blend flours were optimized at 10 % as its pasting and thermal properties were improved. Notably, this ameliorating effect promotes a decrease in hardness and chewiness and an increase in cohesion of the bread cores, presenting better textural attributes and delaying the aging rate during storage. The findings are instructive for applying EBI technology in the manufacture and quality improvement of mixed grain breads and open a new research avenue for processing sorghum staple foods.

Starch-fibers composites, a study of all-polysaccharide foams from microwave foaming to biodegradation

Sustainable composite foams based on rice starch and cellulosic long fibers were successfully fabricated using microwave irradiation. They were presented as a promising method to recycle some of the textile industry waste. A deep study of the processability and functionality of the composites revealed the performance improvement of starch with the addition of long cellulosic fibers, especially with 6 wt% of Arbocel®, in terms of foamability, water, and mechanical resistance features. Moreover, sodium bicarbonate, which acted as a blowing and pulping agent, led to a lower density and better fiber distribution that resulted in an improvement of the foams' functionalities. The range of the study is new in the domain of long fiber foam composites in terms of the foaming capability, and mechanical, thermal, and water resistance properties. Furthermore, all foams showed excellent biodegradability properties against a fungus commonly found in the environment; for example, values around 60 % weight loss after 33 days. Finally, the assessment of the CO2 emission during the process underlines the environmental benefits of the method employed.

Dietary rice bran attenuates hepatic stellate cell activation and liver fibrosis in mice through enhancing antioxidant ability

Various endogenous and exogenous stimuli can result in an inflammatory response and collagen deposition in the liver, which affect liver function and increase the risk of developing liver cirrhosis and cancer. Rice bran, the main by-product of rice milling, contains various nutrients which possess hepatoprotective activities. In this study, we investigated the effects of rice bran on carbon tetrachloride (CCl4)-induced liver fibrosis in mice. Mice were fed a rice-bran-containing diet (10% rice bran w/w) or a standard diet with or without an injection of 20% CCl4 to induce liver fibrosis. Our results showed that feeding a rice-bran-containing diet could alleviate CCl4-induced liver damage, collagen deposition, and expressions of fibrosis-related genes, including α-smooth muscle actin (α-SMA), collagen 1a2 (COL1A2), and transforming growth factor-β (TGF-β) in liver tissues. Moreover, consumption of rice bran enhanced phase II detoxification and antioxidant gene expressions, including Gsta3, Gstp1, Catalase, SOD1, SOD2, and SOD3. Treatment with γ-oryzanol, the major bioactive compound in rice bran, decreased the sensitivity of hepatic stellate cells (HSCs) to TGF-β1-induced α-SMA, COL1A2, and phosphorylated smad2 expressions. In conclusion, a rice-bran-containing diet may have beneficial effects on liver fibrogenesis through increased antioxidant and detoxification activities. γ-Oryzanol, the major bioactive compound of rice bran, can inhibit activation of HSCs.

Physicochemical properties of amorphous granular starch (AGS) prepared by non-thermal gelatinization by high hydrostatic pressure (HHP) and spray drying

Corn starch was gelatinized by high hydrostatic pressure (HHP) and spray drying to make amorphous granular starch (AGS), and their physicochemical properties were compared with the conventionally prepared (heat-gelatinized and spray dried) AGS to devise a novel AGS preparation methodology. Pressure-induced (PAGS) and heat-induced AGS (HAGS) maintained their granular shape but lost their birefringence indicating that both methods could prepare AGS. DSC (differential scanning calorimeter) and XRD (X-ray diffraction) analysis confirmed the complete loss of amylopectin double helices and crystallinity of both PAGS and HAGS. However, their swelling power, solubility, RVA pasting properties, acid/shear stability, gel forming ability and textural properties were completely different. PAGS exhibited constrained swelling, suppressed amylose leaching, and reduced viscosity. Notably, HAGS formed a gel without heating, whereas PAGS yielded a viscous paste with water-soluble attributes. Even after reheating, PAGS maintained its granular structure with comparably less swelling and weaker gel strength than HAGS. Consequently, newly developed PAGS exhibited distinctive characteristics compared to the conventional HAGS, such as lower solubility and swelling power, viscosity, textural properties, and high acid and shear stabilities, rendering it a viable option for various applications within the food industry.

Mechanistic insights into the enhanced texture of potato noodles by incorporation of small granule starches

Potato noodles are a popular food due to their unique texture and taste, but native potato starch often fails to meet consumer demands for precise textural outcomes. The effect of blending small granule (waxy amaranth, non-waxy oat and quinoa) starch with potato starch on the properties of noodles was investigated to enhance quality of noodles. Morphological results demonstrated that small granule starch filled gaps between potato starch granules, some of which gelatinized incompletely. Meanwhile, XRD and FTIR analysis indicated that more ordered structures and hydrogen bonding among starch granules increased with addition of small granule starch. The addition of oat or quinoa starch increased gel elasticity, decreased viscosity of the pastes, and increased the tensile strength of noodles, while addition of 30 % and 45 % waxy amaranth starch did not increase G' value of gel or tensile strength of noodles. These results indicated that amylose molecules played an important role during retrogradation, and may intertwine and interact with each other to enhance the network structure of starch gel in potato starch blended with oat or quinoa starch. This study provides a natural way to modify potato starch for desirable textural properties of noodle product.

An Evaluation of Paddy Rice as an Alternative Energy Source in Protein-Restricted Diets for Growing, Early-Finishing, and Late-Finishing Pigs

Three experiments were conducted to evaluate paddy rice as an alternative energy feedstuff in low-protein diets for pigs. In Experiment 1, a total of 400 growing pigs (20.68 ± 0.29 kg initial bodyweight), were randomly allocated four dietary treatments with 0, 10, 15, and 20% paddy rice for 30 days. Feeding 10% or 15% paddy rice had no adverse impacts on average daily gain (ADG) and feed to gain ratio (F:G), while the inclusion of 20% rice in diets significantly influenced the growth performance of pigs. In Experiment 2, 364 early-finishing pigs (42.25 ± 0.47 kg) were divided into four treatments with 0, 15, 20, and 25% paddy rice for 35 days. Feeding 15% or 20% paddy rice had no negative consequences on growth performance, while pigs fed with 25% rice had the lowest ADG and the greatest F:G. In Experiment 3, 364 late-finishing pigs (79.52 ± 1.28 kg) were divided into four treatments with 0, 20, 25, and 30% paddy rice for 60 days. Paddy rice can be included at up to 30% in diets without compromising growth performance, while feeding with 25% rice significantly improved the performance for pigs compared with the corn-fed control.

Enzymatic Modification of Starch Using Recombinant Genes from Sorghum in Escherichia coli: Insights and Potential Applications

SBEIIb (Sobic.004G163700), SSSIIa (Sobic.010G093400), and GBSSI (Sobic.010G022600) genes that regulate starch synthesis in sorghum endosperm were transferred into Escherichia coli by transgenic technology. SBEIIb, SSSIIa, and GBSSI enzymes were separated and purified through a Ni column and analyzed by electrophoresis with molecular weights and activities of 91.57 84.57, and 66.89 kDa and 551 and 700 and 587 U/μL, respectively. Furthermore, they were applied to starch modification, yielding interesting findings: the A chain content increased from 25.79 to 89.55% for SBEIIb-treated waxy starch, while SSSIIa extended the A chain to form DPs of the B chain, with A chain content decreasing from 89.55 to 37.01%, whereas GBSSI was explicitly involved in the synthesis of B1 chain, with its content increasing from 9.59 to 48.45%. Modified starch was obtained, which could be accurately applied in various industries. For instance, we prepared a sample (containing 89.6% A chain content) with excellent antiaging and antidigestion properties through SBEIIb modification. Moreover, higher RS3 (34.25%) and SDS contents (15.75%) of starch were obtained through the joint modification of SBEIIb and SSSIIa. These findings provide valuable insights for developing sorghum starch synthesis-related enzymes and offer opportunities for improving starch properties through enzymatic approaches.

Impact of germination on the techno-functional properties, nutritional composition, and health-promoting compounds of brown rice and its products: A review

Rice is a popular grain and forms part of the daily diet of people throughout the world. However, the consumption of rice and its products is sometimes limited by its high glycemic index due to its high starch content, low protein content and quality, and low bioavailability of minerals due to the presence of anti-nutritional factors. This has partly stimulated research interest in recent times toward the use of bioprocessing techniques such as germination as cheap and natural means to improve the nutritional quality, digestibility, and health properties of cereals, including rice, to partially achieve nutrition and food security in the developing regions of the world. This review highlights the impact of germination on the nutritional quality, health-promoting properties, and techno-functional characteristics of germinated brown rice grains and their products. The review demonstrated that germinated rice grains and their products have improved nutritional quality and digestibility, modified functional properties, and showed antioxidant, anti-inflammatory, anti-diabetic, anti-obesity, anti-cancer, and anti-cardiovascular activities. Germination appears to be a suitable bioprocessing method to improve the nutritional quality and bioactive constituents and modify the techno-functional properties of rice grains for diverse food applications and improved global nutrition and food safety.

Morphological, Structural, Thermal, Pasting, and Digestive Properties of Starches Isolated from Different Varieties of Rice: A Systematic Comparative Study

The aim of this study was to compare the properties of isolated starches from ten commonly consumed rice varieties in China and to investigate their possible association. In addition, principal component analysis (PCA) and correlation analysis were performed to demonstrate the weight or relevance of different properties. The starch granules had an irregular polyhedral structure. The crystalline structure had an orthogonal arrangement, which is characteristic of A-type starch with nanocrystals with an orthorhombic crystal structure. In addition, higher levels of rapidly digestible starch (72.43 to 74.32%) and resistant starch (2.27 to 2.3%) were found in glutinous rice starch. The highest content of slowly digestible starch (59.48%) was found in starch isolated from black rice, which may be an ideal rice variety for controlling blood glucose and weight. Starch isolated from red Hani terrace rice showed the highest thermal stability during cooking and the highest resistance to a high shear force treatment. In addition, the PCA suggests that the amylose content of starch largely determines the functional properties of starch and positively correlates with the peak viscosity and setback viscosity of the starch pasting. The results of this study will enrich the scientific knowledge of various rice starches and promote their application in the food industry and other industries.

Comparison of quinoa and highland barley derived dietary fibers influence on the physicochemical properties and digestion of rice starch

This study investigated the potential of highland barley and quinoa dietary fibers, rich in β-glucan and pectin respectively, as cost-effective and nutritionally valuable physical modifiers for rice starch (RS). HPAEC revealed differences between the monosaccharide composition of soluble and insoluble dietary fibers sourced from highland barley and quinoa (HSDF, HIDF, QSDF and QIDF). Results from both RVA and DSC analysis revealed that the addition of low amounts of dietary fiber significantly modified the pasting properties of RS. Notably, the addition of quinoa soluble dietary fiber (QSDF) significantly inhibits the formation of a stable gel network in rice starch, even at low concentrations (0.1 %), as confirmed by rheological measurements. Furthermore, the incorporation of QSDF effectively reduces the content of rapidly digestible starch in rice starch by 15.6 % and increases the content of slowly digestible starch, from 23.36 % ± 3.02 % to 31.07 % ± 3.98 %. By leveraging the compositional richness of these fibers, this research opens up novel opportunities for developing functional food products with improved nutritional profiles, as well as for improving texture and reducing glycemic index (GI) in starch-based foods.

Trends in biopolymer science applied to cosmetics

The term biopolymer refers to materials obtained by chemically modifying natural biological substances or producing them through biotechnological processes. They are biodegradable, biocompatible and non-toxic. Due to these advantages, biopolymers have wide applications in conventional cosmetics and new trends and have emerged as essential ingredients that function as rheological modifiers, emulsifiers, film-formers, moisturizers, hydrators, antimicrobials and, more recently, materials with metabolic activity on skin. Developing approaches that exploit these features is a challenge for formulating skin, hair and oral care products and dermatological formulations. This article presents an overview of the use of the principal biopolymers used in cosmetic formulations and describes their sources, recently derived structures, novel applications and safety aspects of the use of these molecules.

Effects of postponing nitrogen topdressing on starch structural properties of superior and inferior grains in hybrid indica rice cultivars with different taste values

Introduction

Nitrogen (N) fertilizer management, especially postponing N topdressing can affect rice eating quality by regulating starch quality of superior and inferior grains, but the details are unclear. This study aimed to evaluate the effects of N topdressing on starch structure and properties of superior and inferior grains in hybrid indica rice with different tastes and to clarify the relationship between starch structure, properties, and taste quality.

Methods

Two hybrid indica rice varieties, namely the low-taste Fyou 498 and high-taste Shuangyou 573, were used as experimental materials. Based on 150 kg·N hm-2, three N fertilizer treatments were established: zero N (N0), local farmer practice (basal fertilizer: tillering fertilizer: panicle fertilizer=7:3:0) (N1), postponing N topdressing (basal fertilizer: tillering fertilizer: panicle fertilizer=3:1:6) (N2).

Results

The starch granules of superior grains were more complete, and the decrease in small granules content and the stability of starch crystals were a certain extent less than those of inferior grains. Compared with N1, under N2, low-taste and high-taste varieties large starch granules content were significantly reduced by 6.89%, 0.74% in superior grains and 4.26%, 2.71% in inferior grains, the (B2 + B3) chains was significantly reduced by 1.61%, 0.98% in superior grains, and 1.18%, 0.97% in inferior grains, both reduced the relative crystallinity and 1045/1022 cm-1, thereby decreasing the stability of the starch crystalline region and the orderliness of starch granules. N2 treatment reduced the ΔHgel of two varieties. These changes ultimately contributed to the enhancement of the taste values in superior and inferior grains in both varieties, especially the inferior grains. Correlation analysis showed that the average starch volume diameter (D[4,3]) and relative crystallinity were significantly positively correlated with the taste value of superior and inferior sgrains, suggesting their potential use as an evaluation index for the simultaneous enhancement of the taste value of rice with superior and inferior grains.

Discussion

Based on 150 kg·N hm-2, postponing N topdressing (basal fertilizer: tillering fertilizer: panicle fertilizer=3:1:6) promotes the enhancement of the overall taste value and provides theoretical information for the production of rice with high quality.

Sustainable production of naturally colored extruded breakfast cereals from blends of broken rice and vegetable flours

There is a growing demand for practical and healthy food products. Obtaining naturally colored breakfast cereals with the incorporation of functional ingredients is a promising alternative for consumers that are looking for healthiness. This study aimed to evaluate the feasibility of using vegetable flours, rich in pigments, to obtain naturally colored breakfast cereals through thermoplastic extrusion. Vegetables considered "unsuitable for the retail market", classified as "type B", were used to prepare different flours from carrot (CF), spinach (SF) and beetroot (BF). Extrudates were produced from a mixture of 90% broken rice (BR) and 10% vegetable flour (CF, SF or BF). Besides giving the extrudates a natural color, the use of vegetable flours also provided nutritional and functional enrichment due to increased mineral, protein, lipid, fiber and phenolic compound contents, and greater antioxidant capacity. However, some of these components, such as fibers, affect extrudate physical structure and technological characteristics, evidenced by reduced expansion, hardness, paste viscosity and greater interaction with water present in milk under consumption conditions. In general, the evaluated flours proved to be an alternative for imparting a natural color to extruded breakfast cereals, in addition to positively contributing to their nutritional and functional value.

Understanding the Relationship between the Molecular Structure and Physicochemical Properties of Soft Rice Starch

The relationship between the molecular structure and physicochemical properties of soft rice starch (SRS) has been investigated in this research. The amylose content of SRS ranged from 10.76% to 11.85%, classified as the very low amylose type. Compared to waxy and japonica rice starch, the largest amount of small starch granules and the highest viscosity were shown in the SRS. The results of X-ray diffraction and Fourier transform infrared proved that the SRS depicted a typical A-type pattern with a low short-range ordered structure. Additionally, SRS had a great deal of A and B1 chains. Molecular weights and density of starch from soft rice were lower than those from waxy rice but higher than those from japonica rice. Furthermore, SRS possessed a higher amount of resistant starch. Correlation analysis indicated that the amylose content and the chain-length distributions of amylopectin play a major role in influencing the molecular structure and physicochemical properties of rice starch. In conclusion, the low amylose content, highest viscosity, and other excellent properties of soft rice starch make it have bright application prospects in instant rice and rice cakes.

A review of green methods used in starch-polyphenol interactions: physicochemical and digestion aspects

The interactions of starch with lipids, proteins, and other major food components during food processing are inevitable. These interactions could result in the formation of V-type or non-V-type complexes of starch. The starch-lipid complexes have been intensively studied for over five decades, however, the complexes of starch and polyphenols are relatively less studied and are the subject of recent interest. The interactions of starch with polyphenols can affect the physicochemical properties and its digestibility. The literature has highlighted several green methods such as ultrasound, microwave, high pressure, extrusion, ball-milling, cold plasma etc., to assist interactions of starch with polyphenols. However, comprehensive information on green methods to induce starch-polyphenol interactions is still scarce. Therefore, in light of the importance and potential of starch-polyphenol complexes in developing functional foods with low digestion, this review has summarized the novel green methods employed in interactions of starch with flavonoids, phenolic acids and tannins. It has been speculated that flavonoids, phenolic acids, and tannins, among other types of polyphenols, may have anti-digestive activities and are also revealed for their interaction with starch to form either an inclusion or non-inclusion complex. Further information on the effects of these interactions on physicochemical parameters to understand the chemistry and structure of the complexes is also provided.

A novel method for obtaining high amylose starch fractions from debranched starch

High amylose starch shows wide applications in food and non-food-based industries. Traditional complex-precipitation approach for the amylose fractionation required a large volume of organic reagents and was possibly risky for food safety. The object of this work was to establish a novel method to obtain starch fractions rich in amylose from debranch starch through repeated short-term retrogradation and centrifugation. Four starch fractions were obtained with the amylose content of 52.08% (C1), 62.28% (C2), 63.58% (C3), and 64.74% (C4). The thermograms of samples displayed that multiple endothermic peaks were detected in C1 and C2 and only one endothermic peak with melting temperature over 120 °C were observed in C3 and C4, indicating their differences in retrogradation behavior. The chain length distribution results of sample exhibited that C1 and C2 contained more short chains (DP ≤ 24), while C3 and C4 consisted of mainly long chains (DP ≥ 25). Accordingly, the differences in fine structures could provide more choices for these fractionated high amylose starch to utilize in practical applications.

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 Genotype × Environment on Physicochemical and Sensory Properties and Differences of Volatile Organic Compounds of Three Rice Types (Oryza sativa L.)

Understanding the effects of genotype, environment and their interactions on rice quality is of great importance for rice breeding and cultivation. In this study, six rice varieties with two indica, two japonica and two indica-japonica types of rice were selected and planted at ten locations in Zhejiang Province to investigate the genotype (G) × environment (E) on physicochemical and sensory properties and the differences of volatile organic compounds (VOCs) among the three types of rice. Analysis of variances showed that apparent amylose content (AC), total protein content (PC), alkali spreading value (ASV), RVA profiles, and appearance (ACR), palatability (PCR), and sensory evaluation value (SEV) of cooked rice and texture of cooled cooked rice (TCCR) were mainly affected by genotypic variation, whereas the smell of cooked rice (SCR) was mainly affected by environment (p < 0.05). The G × E effect was significant for most parameters. The weather in the middle and late periods of filling had important effects on the formation of rice quality, especially on setback (SB) and pasting temperature (PT) (p < 0.01). They were negatively correlated with the texture of cooked rice (TCR) and SEV (p < 0.05). Peak viscosity (PV) and breakdown (BD) were positively related to the sensory evaluation parameters (p < 0.01) and could be used to predict cooked rice quality. A total of 59 VOCs were detected, and indica, japonica and indica-japonica had 9, 6 and 19 characteristic compounds, respectively. The principal component analysis showed that the physicochemical and sensory properties and VOCs of indica-japonica rice were more stable than those of indica and japonica rice at ten locations in Zhejiang Province. It is helpful for rice breeders to understand how the environment affects the physicochemical, sensory properties and VOCs of the three rice types, and it is also important for food enterprises to provide rice products with stable quality.

Optimizing the Functional Properties of Starch-Based Biodegradable Films

A definitive screening design was used in order to evaluate the effects of starch, glycerol and montmorillonite (MMT) concentrations, as well as the drying temperature, drying tray type and starch species, on packaging film's functional properties. Optimization showed that in order to obtain films with the minimum possible thickness, the maximum elongation at break, the maximum tensile strength, as well as reduced water vapor permeability and low opacity, a combination of factors should be used as follows: 5.5% wt starch concentration, 30% wt glycerol concentration on a dry starch basis, 10.5% wt MMT concentration on a dry starch basis, 45 °C drying temperature, chickpea as the starch species and plexiglass as the drying tray type. Based on these results, starch films were prepared, and fresh minced meat was stored in them for 3 days. It was shown that the incorporation of MMT at 10.5% wt on a dry starch basis in the packaging films led to a decreased mesophilic and psychrotrophic bacteria growth factor compared to commercial packaging. When assessed for their biodegradability, the starch films disintegrated after 10 days of thermophilic incubation under simulated composting conditions. Finally, to prove their handling capability during industrial production, the starch films were rewound in a paper cylinder using an industrial-scale rewinding machine.

Modification of Starches and Flours by Acetylation and Its Dual Modifications: A Review of Impact on Physicochemical Properties and Their Applications

Various modification treatments have been carried out to improve the physicochemical and functional properties of various types of starch and flour. Modification by acetylation has been widely used to improve the quality and stability of starch. This review describes the effects of acetylation modification and its dual modifications on the physicochemical properties of starch/flour and their applications. Acetylation can increase swelling power, swelling volume, water/oil absorption capacity, and retrogradation stability. The dual modification of acetylation with cross-linking or hydrothermal treatment can improve the thermal stability of starch/flour. However, the results of the modifications may vary depending on the type of starch, reagents, and processing methods. Acetylated starch can be used as an encapsulant for nanoparticles, biofilms, adhesives, fat replacers, and other products with better paste stability and clarity. A comparison of various characteristics of acetylated starches and their dual modifications is expected to be a reference for developing and applying acetylated starches/flours in various fields and products.

Moderate Reduction in Nitrogen Fertilizer Results in Improved Rice Quality by Affecting Starch Properties without Causing Yield Loss

The quality and starch properties of rice are significantly affected by nitrogen. The effect of the nitrogen application rate (0, 180, and 230 kg ha^-1) on the texture of cooked rice and the hierarchical structure and physicochemical properties of starch was investigated over two years using two japonica cultivars, Bengal and Shendao505. Nitrogen application contributed to the hardness and stickiness of cooked rice, reducing the texture quality. The amylose content and pasting properties decreased significantly, while the relative crystallinity increased with the increasing nitrogen rates, and the starch granules became smaller with an increase in uneven and pitted surfaces. The proportion of short-chain amylopectin rose, and long-chain amylopectin declined, which increased the external short-range order by 1045/1022 cm^-1. These changes in hierarchical structure and grain size, regulated by nitrogen rates, synergistically increased the setback viscosity, gelatinization enthalpy and temperature and reduced the overall viscosity and breakdown viscosity, indicating that gelatinization and pasting properties were the result of the joint action of several factors. All results showed that increasing nitrogen altered the structure and properties of starch, eventually resulting in a deterioration in eating quality and starch functional properties. A moderate reduction in nitrogen application could improve the texture and starch quality of rice while not impacting on the grain yield.

Thick layer drying and storage of rice grain cultivars in silo-dryer-aerator: Quality evaluation at low drying temperature

Drying rice in a single layer in a silo-dryer-aerator allows uniform drying. The objective of this study was to evaluate the physical, physicochemical, and morphological quality of rice grain cultivars (IRGA 424, BRS Pampeira, and Guri INTA) in the lower (initial time) and upper (final time) layers in a silo-dryer-aerator, employing single-layer loading at low temperatures, using the methods of near-infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, and multivariate statistical analysis. Drying rice in silo-dryer-aerator attenuated the moisture diffusivity in the grains, minimizing its effects on the physical, physicochemical, and morphological properties of the grains. However, the physicochemical constituents and morphology of starch were preserved by the low drying temperatures, mainly in the lower layers throughout the 2-month drying. The rice grains of the Guri INTA and BRS Pampeira cultivars were the most resistant to drying and showed greater uniformity on the final quality.

Structural, functional and mechanistic insights uncover the role of starch in foxtail millet cultivars with different congee-making quality

Ten foxtail millet cultivars with different congee-making quality were investigated for relationships between starch structures, functional properties and congee-making qualities. Swelling power, pasting peak viscosity (PV) and setback (SB), gel hardness and resilience, and gelatinization onset (T_o), peak (T_p) and range (R) temperature were correlated with congee-making performance significantly. Good eating-quality cultivars with these parameters were in the range of 15.41-18.58 %, 3095-3279 cp, 1540-1745 cp, 430-491 g, 0.47-0.57, 64.43-65.28 °C, 69.97-70.32 °C and 23.38-24.52 °C, respectively. Correlation analysis showed that amylose, amylopectin B₂ chains and A₂₁ were essential parameters controlling the functional properties. Amylose molecules with linear molecular morphology would cause crystal defects and a wide range of molecular weight distribution. Additionally, they were more prone to re-association, which influenced the PV, SB, T_o, T_p and gel hardness. B₂ chains impacted the gelatinization temperature range (R), gel resilience and swelling behavior by affecting the alignment of double helices and the size of starch particles and pores. Starch with more binding sites of bound water (A₂₁) tended to leach from the swelling granules easily and contributed to higher values of PV. The content of amylose, B₂ chains and A₂₁ of good eating-quality cultivars were 16.19-18.46 %, 11.60-11.69 % and 96.50-97.02 %, respectively.

Combined effects of SSII-2RNAi and different Wx alleles on rice grain transparency and physicochemical properties

Near-isogenic lines Nip(Wx^b/SSII-2), Nip(Wx^b/ss2-2), Nip(Wx^mw/SSII-2), Nip(Wx^mw/ss2-2), Nip(Wx^mp/SSII-2) and Nip(Wx^mp/ss2-2) in the Nipponbare (Nip) background containing the SSII-2RNAi cassette combined with different Waxy (Wx) alleles were investigated in terms of rice grain transparency and quality profiles. Rice lines carrying the SSII-2RNAi cassette displayed downregulation of SSII-2, SSII-3 and Wx genes. Introduction of the SSII-2RNAi cassette decreased apparent amylose content (AAC) in all transgenic lines, but grain transparency differed between low AAC rice lines. Grains from Nip(Wx^b/SSII-2) and Nip(Wx^b/ss2-2) were transparent, while those of rice were increasingly translucent with decreasing moisture due to cavities within starch granules. Rice grain transparency was positively correlated with grain moisture and AAC, but negatively correlated with cavity area within starch granules. Starch fine structure analysis revealed a marked increase in short amylopectin chains with DP 6-12, but a decrease in intermediate chains with DP 13-24, resulting in decreased gelatinisation temperature. Starch crystalline structure analysis showed that the transgenic rice starches have lower crystallinity and lamellar repeat distance than controls due to differences in starch fine structure. The results highlight the molecular basis underpinning rice grain transparency, and provide strategies for improving rice grain transparency.

Some Aspects of the Physiology of the Nyctotherus velox, a Commensal Ciliated Protozoon Taken from the Hindgut of the Tropical Millipede Archispirostreptus gigas

In this paper, the growth requirements, fermentation pattern, and hydrolytic enzymatic activities of anaerobic ciliates collected from the hindgut of the African tropical millipede Archispirostreptus gigas are described. Single-cell molecular analysis showed that ciliates from the millipede hindgut could be assigned to the Nyctotherus velox and a new species named N. archispirostreptae n. sp. The ciliate N. velox can grow in vitro with unspecified prokaryotic populations and various plant polysaccharides (rice starch-RS, xylan, crystalline cellulose20-CC, carboxymethylcellulose-CMC, and inulin) or without polysaccharides (NoPOS) in complex reduced medium with soluble supplements (peptone, glucose, and vitamins). Specific catalytic activity (nkat/g of protein) of α amylase of 300, xylanase of 290, carboxymethylcellulase of 190, and inulinase of 170 was present in the crude protein extract of N. velox. The highest in vitro dry matter digestibility was observed in RS and inulin after 96 h of fermentation. The highest methane concentration was observed in xylan and inulin substrates. The highest short-chain fatty acid concentration was observed in RS, inulin, and xylan. In contrast, the highest ammonia concentration was observed in NoPOS, CMC, and CC. The results indicate that starch is the preferred substrate of the N. velox. Hydrolytic enzyme activities of N. velox showed that the ciliates contribute to the fermentation of plant polysaccharides in the gut of millipedes.

Investigation of critical properties of Cassava (Manihot esculenta) peel and bagasse as starch-rich fibrous agro-industrial wastes for biodegradable food packaging

Cassava peel and bagasse are fibrous, starch-rich agro-industrial wastes, which cause severe environmental impacts upon their disposal. However, these can be raw materials for biodegradable food packaging. In this study, their morphological, chemical, thermal properties, crystalline phases, and chemical compositions were investigated, and potential utilisation as alternative biodegradable food packaging matrices has been assessed. Residual starches in cassava peel and bagasse were morphologically similar with that of commercial cassava starch, whereas potassium (8570 ± 56 mg/kg), and calcium (5300 ± 147 mg/kg) were highly abounded in peel and bagasse respectively. The major crystalline phase, α-amylose dihydrate, for cassava peel (97.1 (2) %) and bagasse (99.0 (3) %) point towards the presence of starch. Calcium and silicon reported to be in crystalline phases respectively, in the forms of quartz and whewellite. These beneficial characteristics suggested the potential valorisation of cassava peel and bagasse with special interest as matrices for biodegradable food packaging.

Generating waxy rice starch with target type of amylopectin fine structure and gelatinization temperature by waxy gene editing

Waxy rice, which lacks amylose, is an important variant in rice, and its starches have been widely used. New waxy rice varieties generated via the CRISPR/Cas9 gene-editing system is described. Herein, four waxy rice starches with different physicochemical properties were successfully obtained by the CRISPR/Cas9 editing Waxy (Wx) gene. The results showed that the amylose content (AC) of wx mutant starches ranged from 0.26 to 1.78 %, and CZBwx1 starches had the best gel consistency and highest water solubility among all wx mutants. Mutations of Wx^b allele produced more short-chains (degree of chain polymerization (DP) 6-11), and less medium- and long-chains (DP12-70) than that of Wx^a, while the AC of Wx^a allele mutants was higher than the mutations of Wx^b allele. The gelatinization temperature (GT) of wx^a mutant starches was higher than that of wx^b mutant starches. Moreover, we found that the GT and amylopectin fine structure type of waxy rice starch did not change after Wx gene editing. Based on these findings, it is possible to produce waxy rice starch with different physicochemical properties, containing target GT and chain length distributions of amylopectin.

Influence of accelerating storage of foxtail millet on the edible and cooking quality of its porridge: An insight into the structural alteration of the in-situ protein and starch and physicochemical properties

This study aimed to elucidate the effect of the accelerating storage (40 °C, 10 weeks) of foxtail millet on the edible and cooking quality of its porridge. The structural alteration of the in-situ protein and starch in foxtail millet, as well as the physicochemical properties were investigated. Both the homogeneity and palatability of millet porridge were significantly improved after 8-week storage of millet, while its proximate compositions remained unchanged. Meanwhile, the accelerating storage increased the water absorption and swelling of millet by 20 % and 22 %, respectively. The morphological studies (using the SEM, CLSM and TEM) revealed that the starch granules in the stored millet became easier to swell and melt, leading to better gelatinization with a higher coverage extension in protein bodies. FTIR results showed that the protein hydrogen bonds in the stored millet became stronger and the starch ordered degree was reduced. Compared to the native foxtail millet, the peak, trough, final, and setback viscosity of the stored sample increased by 27 %, 76 %, 115 % and 143 %, respectively, while the onset, peak, and conclusion temperature increased by 0.80, 1.10 and 0.80 °C, respectively. Besides, the G' and G″ of the stored foxtail millet were significantly higher than its native counterpart.

Rice yield penalty and quality deterioration is associated with failure of nitrogen uptake from regreening to panicle initiation stage under salinity

In recent years, the development and utilization of saline land for rice cultivation have effectively expanded grain productivity. Rice is a salt-sensitive crop, and the increasing salinity problem threatens rice yield and quality. Therefore, we conducted open field experiments to study the effect of salinity on different growth stages of rice. Irrigating saline treatment was conducted at three different growth stages: irrigating saline from the regreening stage to the panicle initiation stage (S1), irrigating saline from the panicle initiation stage to the flowering stage (S2), and irrigating saline from the flowering stage to the maturity stage (S3). Each treatment period lasted for about 30 days. At the same time, irrigating saline water from the regreening stage to the maturity stage (S4) treatment was added in 2022 to explore the performance of salt stress during the whole growth period of rice. Based on the treatment of these different saline irrigation growth periods, three saline concentrations were incorporated, including salinity 0‰ (T1), 3‰ (T2), and 6‰ (T3) concentrations. No irrigating saline during the whole growth period was also used as a control (CK). The results indicated that rice grain yield and quality were most sensitive to saline treatment during S1 among the three stress periods. At the S1 stage, salinity mainly reduced the nitrogen uptake, resulting in stunted plant growth, reducing tillering, yield, and yield components, and deteriorating the rice quality. Compared to the control, IE_N (grain yield over the total amount of N uptake in plants at maturity) was more sensitive at the S1 stage than S2 and S3 stages under salinity. Furthermore, the findings of our study suggest that under salinity, rice growth is not only directly affected by the higher sodium (Na⁺) content in plants, but the higher concentration of Na⁺ reduced the ability of plants to uptake nitrogen. Thus, more attention should be paid to the field management of the S1 stage, the most sensitive stage during rice cultivation in salinized areas. It is necessary to avoid salt damage to rice during this period and ensure irrigation with precious freshwater resources.

Rice thermoplastic starch nanocomposite films reinforced with nanocellulose

Rice starch is a raw material with proven potential in obtaining biodegradable polymers. Plasticization improves the flexibility characteristics of starch-based films, although they still tend to have low tensile strength and high hydrophilicity. The addition of nanocellulosic materials is an alternative to improve these characteristics. In this chapter, the effects of adding different sources and concentrations of nanocellulose (NC) on the properties of thermoplastic rice starch films (TRSF) are addressed. One can highlight as main effects the increase of tensile strength and transparency of the films, the reduction of water vapor permeability and water solubility. The type of NC used, the way it is obtained, as well as its interaction with starch molecules are factors that influence the effects. Further studies involving the interaction of TRSF and NC should be conducted in order to overcome the lack of information.

Effects of Slow-Release Fertilizer on Lotus Rhizome Yield and Starch Quality under Different Fertilization Periods

Slow-release fertilizer is an environmentally friendly fertilizer that is widely used in crop cultivation instead of traditional nitrogen fertilizer. However, the optimal application time of slow-release fertilizer and its effect on starch accumulation and rhizome quality of lotus remains unclear. In this study, two slow-release fertilizer applications (sulfur-coated compound fertilizer, SCU, and resin-coated urea, RCU) were fertilized under three fertilization periods (the erect leaf stage, SCU1 and RCU1; the erect leaf completely covering the water stage, SCU2 and RCU2; and the swelling stage of lotus rhizomes, SCU3 and RCU3) to study the effects of different application periods. Compared with CK (0 kg∙ha^-1 nitrogen fertilizer), leaf relative chlorophyll content (SPAD) and net photosynthetic rate (Pn) remained at higher levels under SCU1 and RCU1. Further studies showed that SCU1 and RCU1 increased yield, amylose content, amylopectin and total starch, and the number of starch particles in lotus, and also significantly reduced peak viscosity, final viscosity and setback viscosity of lotus rhizome starch. To account for these changes, we measured the activity of key enzymes in starch synthesis and the relative expression levels of related genes. Through analysis, we found that these parameters increased significantly under SCU and RCU treatment, especially under SCU1 and RCU1 treatment. The results of this study showed that the one-time application at the erect leaf stage (SCU1 and RCU1) could improve the physicochemical properties of starch by regulating the key enzymes and related genes of starch synthesis, thus improving the nutritional quality of lotus rhizome. These results provide a technical choice for the one-time application of slow-release fertilizer in lotus rhizome production and cultivation.

Technological and prebiotic aspects of young bamboo culm flour (Dendrocalamus latiflorus) combined with rice flour to produce healthy extruded products

Young bamboo culm flour (YBCF) has proved to be a healthy and sustainable ingredient, due to its high fiber content and high yield of bamboo crops. The present study evaluated the effects of YBCF from Dendrocalamus latiflorus on the physicochemical, technological properties and prebiotic activity of rice-based extrudates aiming to expand its application. The extrudates were produced in a twin-screw extruder with different RF:YBCF concentrations (100:0; 95:5, 90:10, and 85:15 %). During the process, the specific mechanical energy increased as YBCF content increased because of the high shear favored by YBCF particles. With increasing RF replacement by YBCF, the extruded products presented a significant (p < 0.05, by the Scott-Knott test) increase in hardness (57.37 to 82.01 N) and water solubility index (12.80 to 34.10 %), as well as a decrease in color luminosity (L*=85.49 to 82.83), expansion index (2.68 to 1.99), and pasting properties. In addition, all extrudate samples presented bifidogenic activity. Therefore, YBCF exhibited attractive technological properties and can be used as an ingredient in the production of healthy and sustainable extruded products.

GF14f gene is negatively associated with yield and grain chalkiness under rice ratooning

BACKGROUND

Ratoon rice cropping has been shown to provide new insights into overcoming the current challenges of rice production in southern China. However, the potential mechanisms impacting yield and grain quality under rice ratooning remain unclear.

METHODS

In this study, changes in yield performance and distinct improvements in grain chalkiness in ratoon rice were thoroughly investigated, using physiological, molecular and transcriptomic analysis.

RESULTS

Rice ratooning induced an extensive carbon reserve remobilization in combination with an impact on grain filling, starch biosynthesis, and ultimately, an optimization in starch composition and structure in the endosperm. Furthermore, these variations were shown to be associated with a protein-coding gene: GF14f (encoding GF14f isoform of 14-3-3 proteins) and such gene negatively impacts oxidative and environmental resistance in ratoon rice.

CONCLUSION

Our findings suggested that this genetic regulation by GF14f gene was the main cause leading to changes in rice yield and grain chalkiness improvement of ratoon rice, irrespective of seasonal or environmental effects. A further significance was to see how yield performance and grain quality of ratoon rice were able to be achieved at higher levels via suppression of GF14f.

Citric acid esterified Glutinous Assam bora rice starch enhances disintegration and dissolution efficiency of model drug

The current work was designed to study the starch's physicochemical attributes, tablet disintegration and dissolution efficiency and its derivatives obtained from the glutinous Assam bora rice (G-ABR) variety of Assam, Northeast India. Starch was isolated by a simple protein denaturation method, and a starch derivative was prepared through citric acid modification. G-ABRS and citrated G-ABRS were characterized through FTIR, DSC, XRD and SEM. The rate of consolidation, consolidation index, angle of internal friction, packing rearrangement and cohesive properties were determined to investigate their applications as functional excipients in pharmaceutical industries. G-ABRS and citrated G-ABRS exhibited better packing rearrangement and cohesive properties than standard corn starch. Furthermore, immediate release of API from the tablet compact was observed when the starch concentration increased from 1 to 5 %, indicating facilitation of the tablet compact disintegration. Therefore, G-ABRS and citrated G-ABRS are potentially functional and sustainable materials for pharmaceutical industries.

Effects of post-silking drought stress degree on grain yield and quality of waxy maize

BACKGROUND

Drought stress (DS) induced by post-silking have a major impact on the yield and quality of maize. In this study, the effects of different degrees of DS after pollination on grain filling, starch and protein metabolism, and functional properties were investigated using two waxy maize cultivars as materials. The levels of DS that were investigated were 'mild water stress' (WS1), 'moderate water stressed' (WS2), and 'severe waterstressed' (WS3).

RESULTS

Drought stress decreased grain fresh weight, dry weight, and moisture content in both cultivars during grain filling, and reduced kernel number, kernel weight, and grain yield at maturity. The effect on grain development and yield formation gradually increased with drought aggravation. The water stress (WS) treatment downregulated the enzymatic activities related to starch biosynthesis during grain-filling process, accompanied by a decrease in soluble sugar and starch deposition. The WS treatment increased the enzymatic activities involved in protein synthesis during grain-filling process, thereby increasing the protein content of grains. On average, WS2 and WS3 treatments reduced the pasting viscosities and increased the gelatinization temperatures of grains, with WS3 having the greatest effect. However, the changes of setback viscosity, gelatinization enthalpy, retrogradation enthalpy, and retrogradation percentage under WS treatment were inconsistent in both cultivars. Pearson correlation analysis showed that starch content was negatively correlated with gelatinization temperatures and positively correlated with pasting viscosities in both cultivars. However, grain pasting  and gelatinization properties have opposite correlations with protein content and starch content.

CONCLUSIONS

These findings suggest that post-silking DS regulated the grain-filling process and starch and protein biosynthesis, which influenced grain yield and quality. © 2022 Society of Chemical Industry.

Low temperature and light combined stress after heading on starch fine structure and physicochemical properties of late-season indica rice with different grain quality in southern China

Late-season indica rice frequently encounters low temperature (LT) along with low light (LL) after heading in southern China, which deteriorates the grain quality by altering starch quality. However, the detailed effects on starch properties of these stressors remain unclear. Herein, two indica rice cultivars with good and poor grain quality were grown under control (CK), LT, and LT + LL conditions after heading and the structural and physicochemical properties of their starch were evaluated. Compared with CK, LT and LT + LL worsened thermal and pasting properties of starch in the two cultivars, mainly because they increased branch chain branching and A chain (DP ≤12), and decreased average branch chain length and crystallinity. Compared with LT, LT + LL deteriorated the pasting properties of the poor-quality cultivar, such as reducing breakdown (BD), final and peak viscosity, which mainly owing to decreasing the starch branching and crystallinity degrees, and increasing the small starch granules (d < 10 μm). Gelatinization enthalpy and BD both had significant and positive correlations with amylose content, the ratio of amylose and amylopectin, B3 chain and crystallinity. Taken together, these results suggest that LT and LT + LL during grain filling can deteriorate the physicochemical properties of starch in late-season indica rice cultivars by disrupting starch multilevel structure, especially upon LT + LL. In particular, while poor-quality cultivar had poorer physicochemical properties, the good-quality cultivar had poorer thermal properties under LT + LL.

Starch Chemical Composition and Molecular Structure in Relation to Physicochemical Characteristics and Resistant Starch Content of Four Thai Commercial Rice Cultivars Differing in Pasting Properties

Variations in starch pasting properties, considered an alternative potential quality classification parameter for rice starches, are directly controlled by the diverse starch molecular composition and structural features. Here, the starch characteristics of four rice cultivars (i.e., RD57, RD29, KDML105, and RD6) differing in pasting properties were assessed, and their relationship was determined. The results revealed that protein and moisture contents and their crystalline type were similar among the four rice starches. However, their molecular compositions and structures (i.e., reducing sugar and amylose contents, amylopectin branch chain-length distributions, granule size and size distribution, and degree of crystallinity) significantly varied among different genotypes, which resulted in distinct swelling, solubility, gelatinization, retrogradation, and hydrolytic resistance properties. The swelling power and gelatinization enthalpy (∆H) were positively correlated with C-type granule and relative crystallinity, but were negatively correlated with amylose content, B-type granule and median particle size (d(0.5)). Conversely, the water solubility and resistant starch content negatively correlated with C-type granule, but positively correlated with amylose content, B-type granule, and d(0.5). The gelatinization onset temperature (To(g)), and retrogradation concluding temperatures (Tc(r)), enthalpy (∆H(r)), and percentage (R%) were positively impacted by the amount of protein, amylose, and B1 chains (DP 13-24), while they were negatively correlated with short A chains (DP 6-12). Collectively, the starch physicochemical and functional properties of these Thai rice starches are attributed to an interplay between compositional and structural features. These results provide decisive and crucial information on rice cultivars' suitability for consumption as cooked rice and for specific industrial applications.

Effect of extrusion parameters on the interaction between rice starch and glutelin in the preparation of reconstituted rice

Reconstituted rice produced by extrusion has been attracted attention due to nutritional fortification and convenient production. Nevertheless, how to achieve desirable qualities and physicochemical properties of reconstituted rice nearly to natural rice by regulating extrusion process parameters is difficult. Herein, rice starch/glutelin mixture as raw material of reconstituted rice was extruded at varying extrusion conditions. Specific mechanical energy (SME) and sectional expansion index (SEI) dropped with rise in density (R² = 0.9117 and 0.8207). Solubility was enhanced with increase in product temperature (R² = 0.9085), color darkened and shifted to reddish and yellowish as extrusion temperature increased (R² = 0.8577). These trends were well fitted by sigmoid models. Furthermore, SME enhanced hydrophobic and electrostatic interactions between rice starch and glutelin and caused the reduction in crystallinity and thermal stability, promoting the formation of a bi-continuous matrix of protein aggregates with rice starch. The obtained results can be applied to guide the production of reconstituted rice with desirable qualities.

Highland Barley Starch: Structures, Properties, and Applications

Highland barley (HB) is a nutritious crop with excellent health benefits, and shows promise as an economically important crop with diverse applications. Starch is the main component of HB and has great application potential owing to its unique structural and functional properties. This review details the latest status of research on the isolation, chemical composition, structure, properties, and applications of highland barley starch (HBS). Suggestions regarding how to better comprehend and utilize starches are proposed. The amylopectin content of HBS ranged from 74% to 78%, and can reach 100% in some varieties. Milling and air classification of barley, followed by wet extraction, can yield high-purity HBS. The surface of HBS granules is smooth, and most are oval and disc-shaped. Normal, waxy, and high-amylose HBS have an A-type crystalline. Due to its superb freeze-thaw stability, outstanding stability, and high solubility, HBS is widely used in the food and non-food industries. The digestibility of starch in different HB whole grain products varies widely. Therefore, the suitable HB variety can be selected to achieve the desired glycemic index. Further physicochemical modifications can be applied to expand the variability in starch structures and properties. The findings provide a thorough reference for future research on the utilization of HBS.

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.

Structure and properties of flexible starch-based double network composite films induced by dopamine self-polymerization

Starch-based packaging materials are being developed to alleviate environmental pollution and greenhouse gas emissions associated with plastic-based ones. However, the high hydrophilicity and poor mechanical properties of pure-starch films limit their widespread application. In this study, dopamine self-polymerization was used as a strategy to improve the performance of starch-based films. Spectroscopy analysis showed that strong hydrogen bonding occurred between polydopamine (PDA) and starch molecules within the composite films, which significantly altered their internal and surface microstructures. The composite films had a greater water contact angle (> 90°), which indicated that the incorporation of PDA reduced their hydrophilicity. Additionally, the elongation at break of the composite films was 11-fold higher than pure-starch films, indicating that PDA improved film flexibility, while the tensile strength decreased to some extent. The composite films also exhibited excellent UV-shielding performance. These high-performance films may have practical applications in food and other industries as biodegradable packaging materials.

The Effects of Starch Molecular Fine Structure on Thermal and Digestion Properties of Rice Starch

Whole white rice is a major staple food for human consumption, with its starch digestion rate and location in the gastrointestinal tract having a critical role for human health. Starch has a multi-scale structure, which undergoes order-disorder transitions during rice cooking, and this structure is a major determinant of its digestibility. The length distributions of amylose and amylopectin chains are important determinants of rice starch gelatinization properties. Starch chain-length and molecular-size distributions are important determinants of nucleation and crystal growth rates, as well as of intra- and intermolecular interactions during retrogradation. A number of first-order kinetics models have been developed to fit starch digestograms, producing new information on the structural basis for starch digestive characteristics of cooked whole rice. Different starch digestible fractions with distinct digestion patterns have been found for the digestion of rice starch in fully gelatinized and retrograded states, the digestion kinetics of which are largely determined by starch fine molecular structures. Current insights and future directions to better understand digestibility of starch in whole cooked rice are summarized, pointing to ways of developing whole rice into a healthier food by way of having slower starch digestibility.