Effect of endogenous proteins and lipids on starch digestibility in rice flour

Effect of endogenous proteins and lipids on yam flour during radio frequency explosion puffing: Characterization, microstructure, function, and in vitro digestibility

Radio frequency explosion puffing (RFEP) can improve yam flour properties, in which endogenous proteins and lipids play an important role, but the action mechanism is unclear. In this study, native yam flour was defatted and/or deproteinized and then treated with RFEP. The results indicated that RFEP caused protein covering layers on the starch surface to become loose, and these loose layers interacted with lipids and then rewrapped tightly around the starch surface to form compact matrixes. The existence of lipids prevented the shedding of protein covering layers from starch surface during RFEP. The compact matrixes caused decrease in intermolecular hydrogen bonds and relative crystallinity and changes in structure of protein peptide group and protein amide II bands. The compact matrixes reduced the contact of water molecules and enzyme with starch, inhibiting the gelatinization, swelling, and digestibility. Endogenous proteins had a greater impact on yam flour properties during RFEP. These findings offer new insights for the development of yam flour products and the extensive application of RFEP technology in the food industry.

Enhancement of the quality and in vitro starch digestibility of fried-free instant noodles with rapid rehydration using sourdough fermented with exopolysaccharide-producing Weissella confusa

This study aimed to enhance the rehydration property of fried-free instant noodles using a fermentation method with exopolysaccharide-producing Weissella confusa, thereby improving their quality. The effect of sourdough fermented with W. confusa on the rehydration property, cooking qualities and in vitro starch digestibility of fried-free instant noodles was investigated. Compared with the control group, the rehydration time of fried-free instant noodles prepared using W. confusa-fermented sourdough supplemented with 2 % sucrose was significantly reduced by 17.36 % from 403 to 333 s, the cooking loss was significantly decreased by 12.72 % from 12.50 % to 10.91 %, and the digestible starch content was significantly increased by 5.40 % from 73.09 % to 77.04 % (p < 0.05). Sourdough fermentation with W. confusa created an acidic environment and produced hydrophilic exopolysaccharides, which significantly enhanced the rehydration property and cooking quality of fried-free instant noodles by improving their degree of gelatinization and reducing their relative crystallinity (p < 0.05).

Effects of fermentation with Lactobacillus plantarum on rice flour: The role of granular characteristics

This study examined the effects of lactic acid bacteria fermentation on the physicochemical and functional properties of the flours from two rice varieties, Shindongjin (SF) and Hitomebore (HF), both with similar amylose content. Fermentation with Lactobacillus plantarum over 48 h resulted in significant changes. Protein content decreased substantially in both varieties, especially in SF, and amylose content increased. Swelling power and solubility also increased more in SF. The gel hardness of fermented SF increased by approximately 22 %, whereas HF showed minimal change. These differences are due to variations in granule rigidity and starch molecule leaching. SF granules maintained rigidity and a robust external network due to higher amylose leaching. In contrast, the lower initial rigidity and higher amylopectin leaching in HF hindered strong gel network formation. These findings offer insights into the structural and molecular mechanisms of rice fermentation with lactic acid bacteria.

Loss-of-function of SSIIa and SSIIIa confers high resistant starch content in rice endosperm

Rice (Oryza sativa L.) endosperm accumulates huge amounts of starch. Rice starch is highly digestible, potentially enhancing the occurrence of blood sugar- and intestine-related diseases such as type 2 diabetes. Resistant starch (RS) is hardly digestible in small intestine but can be converted into beneficial short-chain fatty acids in large intestine, potentially reducing the incidence of these diseases. However, it is still difficult to produce a high RS rice variety. Here, we report that simultaneous deficiency of soluble starch synthases IIa and IIIa confers high RS content in rice endosperm. The ssIIa ssIIIa exhibited higher RS content than did the ssIIIa ssIIIb, a mutant reported currently to have remarkably higher RS content than parental ssIIIa, under our experimental conditions. Loss-of-function of SSIIa and SSIIIa significantly elevated the activity of granule-bound starch synthase I and thus content of amylose. Furthermore, total lipid content increased in mutant seeds, implying that intermediate metabolites spilled out from starch biosynthesis into lipid biosynthesis. The increased amylose content and improved lipid synthesis coordinately contributed to high RS content in mutant seeds. These results further reveal the molecular mechanism of RS occurrence in rice endosperm and provide a critical genetic resource for breeding higher RS rice cultivars.

Removal of proteins and lipids affects structure, in vitro digestion and physicochemical properties of rice flour modified by heat-moisture treatment

BACKGROUND

The objective of this experiment was to investigate the role of endogenous proteins and lipids in the structural and physicochemical properties of starch in heat-moisture treatment (HMT) rice flour and to reveal their effect on starch digestibility under heat.

RESULTS

The findings indicate that, in the absence of endogenous proteins and lipids acting as a physical barrier, especially proteins, the interaction between rice flour and endogenous proteins and lipids diminished. This reduction led to fewer starch-protein inclusion complexes and starch-lipid complexes, altering the granule aggregation structure of rice flour. It resulted in a decrease in particle size, an increase in agglomeration between starch granules, and more surface cracking on rice granules. Under HMT conditions with a moisture content of 30%, slight gelatinization of the starch granules occurred, contributing to an increased starch hydrolysis rate. In addition, the elevated thermal energy effect of HMT enhanced interactions between starch molecular chains. These resulted in a decrease in crystallinity, short-range ordering, and the content of double-helix structure within starch granules. These structural transformations led to higher pasting temperatures, improved hot and cold paste stability, and a decrease in peak viscosity, breakdown, setback, and enthalpy of pasting of the starch granules.

CONCLUSION

The combined analysis of microstructure, physicochemical properties, and in vitro digestion characteristics has enabled us to further enhance our understanding of the interaction mechanisms between endogenous proteins, lipids, and starches during HMT. © 2024 Society of Chemical Industry.

Effect of soluble dietary fiber from corn bran on pasting, retrogradation, and digestion characteristics of corn starch

This study investigated the effect of twin-screw extruded-enzymatically prepared soluble dietary fibers (EESDF) on various properties of CS. Results showed that adding EESDF decreased the viscosity and crystallinity. Incorporating 10 % EESDF reduced the peak and final viscosities of CS by 323 cP and 380 cP, respectively. When stored for 14 d, EESDF reduced the relative crystallinity (RC) and enthalpy of retrogradation (ΔHr) of CS. The RC and the ΔHr were reduced by 4.83 % and 41.53 %, respectively, when adding 10 % EESDF. The resistant starch content was increased by 6.7 % when stored for 0 d with the addition of 10 % EESDF. The eGI value was decreased when adding 10 % EESDF. These findings showed that EESDF inhibited the retrogradation and digestion of CS. They will provide a basis for using EESDF as a quality control for starchy foods and for using starch in soft gels and foods for dysphagic categories.

Starch digestion and physiochemical properties of a newly developed rice variety with low glycemic index

This study aimed to clarify the starch digestion characteristics and related physicochemical properties of the newly developed low-GI rice variety, Ditangliangyou 335 (D335), in comparison with two widely grown rice varieties, Xiangzaoxian 45 (X45) and Zhongzao 39 (Z39). The results showed that D335 had an active digestion duration (286 min) that was 101-190 % shorter, a glucose production rate (1.06 mg g-1 min-1) that was 57-73 % slower, and a total glucose production (303 mg g-1) that was 11-19 % less than X45 and Z39. These differences were attributable to the distinct starch physicochemical properties, including amylose content, amylose-to-amylopectin ratio, starch granule size, amylopectin chain length, and starch molar mass, as well as the different pasting properties of rice flour, such as pasting temperature and breakdown viscosity. These findings reveal the starch digestion characteristics and the key physicochemical properties that determine these characteristics in the low-GI rice variety D335.

Effect of transglutaminase on the interaction of protein and rice starch

The present study aims to investigate the effects of endogenous protein (rice protein, RP) and exogenous proteins (corn protein, CP, and wheat protein, WP) on the physicochemical properties of rice starch under the action of transglutaminase (TG). The findings indicate that, the interactions between exogenous proteins with rice starch are relatively weak. However, with the catalysis of TG, both endogenous and exogenous proteins tightly encapsulate rice starch granules, forming a dense microporous network structure. This phenomenon led to a reduction in starch expansion coefficient and amylose leaching, resulting in an increase in the onset temperature and a notable decrease in viscosity and digestibility. Among them, endogenous protein exerted the greatest influence on the gelatinization properties of rice starch, whereas exogenous protein had the most significant impact on its digestibility. Specifically, the order of influence on the gelatinization characteristics is RP > CP > WP, and for digestibility, it is WP > CP > RP. Furthermore, under the action of TG, both endogenous and exogenous proteins significantly enhanced the short-range ordered structure of starch molecules, contributing to higher crystallinity and a more ordered A-type structure. In conclusion, this study provides a theoretical basis for the construction of starch functional foods.

Effect of rice storage proteins on the physicochemical properties of indica rice during after-ripening

The processing quality of indica rice stabilizes after a period of post-harvest storage known as after-ripening, during which proteins play an important role according to our previous research. The present study investigated the effects of rice storage proteins (RSPs) on the physicochemical properties of after-ripening rice, employing protein analysis, rapid viscosity analyzer, hydration properties assessment, morphological analysis and fourier transform infrared spectroscopy (FTIR). The results indicated that the crude protein content remained relatively unchanged during after-ripening, while the band intensities of 13 kDa and 20 kDa protein subunits increased with increasing storage time. Removing RSPs decreased the setback viscosity, final viscosity and pasting temperature of after-ripening indica rice flour but led to an increase in its breakdown viscosity, especially by 93.45 % after storage at 36 °C for 90 d. Protein-removal also contributed to increasing the water solubility and swelling power of after-ripening indica rice flour by 31.66 % and 37.31 % for 90 d respectively. Morphological analysis revealed that RSPs had wrapped the starch granules, thus delaying the migration of water into the starch during heating. FTIR spectra indicated that the presence of RSPs enhanced the short-range ordered structure of starch. These findings will contribute to further elucidating the mechanisms underlying indica rice quality changes during storage.

Effect of Modification by β-Amylase and α-Glucosidase on the Structural and Physicochemical Properties of Maize Starch

Single enzymatic modifications are limited to starch. Complex modification with synergistic amylases will improve starch properties more significantly. In this study, maize starch was compound modified by β-amylase and α-glucosidase. The structure and physicochemical properties of the corn starch were determined by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance hydrogen spectroscopy (1HNMR), high-performance anion-exchange chromatography (HPAEC-PAD), differential scanning calorimetry (DSC) and Rapid Visco analyzer (RVA) to determine the changes in the structure and physicochemical properties of maize starch before and after the dual enzyme modification. The branching degree (4.95-7.10%) of maize starch was increased after bi-enzymatic modification, the amylose content (28.77-18.60%) was decreased, and the amylopectin content (70.79-81.71%) was elevated. The relative crystallinity (20.41-30.20%) and short-range ordered structure of the starch increased, and the dual enzyme modification led to a more compact structure. Dual enzyme-modified maize starch showed a decrease in long chains, an increase in short chains, and its degree of branching was elevated. Dual enzyme modification also affected the thermal stability, pasting, light transmittance (1.40-2.16%), solubility (20.15-13.76%), and swelling (33.97-45.79%) of maize starch. It can be concluded that the complex modification of maize starch by β-amylase and α-glucosidase significantly changed the amylose/amylopectin ratio of the starch and made its structure denser. These results can provide a theoretical basis for the enzymatic preparation of maize starch with different amylose/amylopectin ratios and the development and utilization of functional starches.

Influence of protein in low paste viscosities of Bambara groundnut flours from heat-treated Bambara groundnut seeds

Heat treatment of Bambara groundnut seeds has been reported to cause low paste viscosities in resulting flours. Structural changes in Bambara groundnut protein, due to heat treatment, causes the protein to encapsulate starch, making it unavailable to paste causing low paste viscosities. In this study, trypsin was used to hydrolyze proteins in the flour and the microstructure analysis confirmed the disappearance of aggregates. Flour microstructure analysis confirmed hydrolysis of protein from previously aggregated status and showed liberated individual starch granules. Following the treatment of flours by trypsin, Confocal laser scanning microscopy did not show a protein signal. Hydrolysing Bambara groundnut proteins significantly increased the flour paste viscosities (P < 0.05). The final viscosities for flours from 20 % moisture-conditioned and infrared heat-treated seeds for 5 min were 733.9 mPa s before protein hydrolysis and 2081.71 mPa s after protein hydrolysis. The gelatinization temperature (81 °C) did not show a significant change following protein hydrolysis. Sodium dodecyl-sulphate polyacrylamide gel electrophoresis band intensity increased indicative of disulfide bonding and protein polymerisation when microwave and infrared heat treatment were combined. There were changes in Bambara groundnut protein secondary structures such as an increase of 57 % in β-sheet along with a 60 % reduction in the α-helix as shown by the Fourier-transform infrared spectroscopy. The changes in secondary structure of Bambara groundnut protein were caused by microwave and infrared heating. Heat treatment of Bambara groundnut seeds is partly responsible for the reduction in paste viscosities of their flours.

Impact of annealing and incorporation of vegetable oils on physicochemical and rheological properties of wheat starch

This study investigated the impact of annealing treatment and lipids (vegetable oils, such as palm, olive, and grapeseed oils) on the physicochemical and rheological properties of wheat starch. Annealing of wheat starch (WSANN45, WSANN55) under different temperatures (45 °C and 55 °C) and with added vegetable oil (WS-OilANN45, WS-OilANN55) were compared with untreated wheat starch (WS). Annealing at 45 °C resulted in slight changes in the physicochemical properties of starch. However, annealing at 55 °C significantly decreased the relative crystallinity, pasting viscosity, and swelling power. WS-OilANN45 showed a higher ΔH (dissociation peak) than WSANN45, indicating successful lipid incorporation, whereas WS-OilANN55 showed no significant difference from WSANN55, suggesting that lipid integration was not achieved. Rheological tests showed that WS-OilANN45 slightly reduced the shear-thinning behavior and viscoelastic properties of starch. The introduction of oils affected the swelling and pasting properties, weakened the gel network, and significantly reduced the gel hardness. This approach offers a potential method that uses food-grade oils and annealing to modify starch and alter its rheological and physical properties while retaining its native granular characteristics.

Extruded plant protein two-dimensional scaffold structures support myoblast cell growth for potential applications in cultured meat

Cultured meat has been proposed as a promising alternative to conventional meat products. Five different plant protein blends made from soy (from two different manufacturers), wheat, mung bean, and faba bean, were extruded to form low-moisture meat analogs (LMMA) and were used to assess LMMA scaffold potential for cultured meat application. Extruded LMMAs were characterized using scanning electron microscopy, water-holding capacity, total soluble matter, and mechanical properties. Two-dimensional LMMA scaffolds were seeded with C2C12 skeletal myoblast cells and cultured for 14 days, and cell attachment and morphology were evaluated. All five extrudates exhibited directionality of their fibrous protein structures but to varying degrees. Soy, wheat, mung bean, and faba bean-based LMMA scaffolds initially supported myoblast cell growth. However, after 14 days of culture, the extruded wheat LMMA exhibited superior myoblast cell growth. This may be attributed to the highly aligned fibrous structure of the extruded wheat LMMA as well as its elastic modulus, which closely approximated that of native skeletal muscle. Overall, two-dimensional structures of the extruded plant proteins support cell growth and advance the development of cultured meat.

Relationship between internal structure and in vitro digestibility of A- and B-type wheat starch revealed by chemical surface gelatinization

In this study, the properties of remaining starch granules obtained with different degrees of exfoliation were explored by removing the outer layers of A- and B-type wheat starch (AWS and BWS) granules with chemical surface gelatinization. SEM images revealed significant morphological variations with increasing exfoliation. CLSM and amylose content analysis indicated a predominance of lipid complexes in the outer granule layers, particularly in BWS. The structural characteristics of AWS and BWS were analyzed using PLM, XRD, FT-IR and DSC, verifying the conclusion of the alternation of starch crystalline and amorphous zone. And the amorphous regions are proportionally higher in the inner starch layer. Moreover, raw AWS and BWS granules were more easily digested from the outside in, with the RS content decreasing from 80.65 % to 66.92 % and 49.06 % to 45.01 %, respectively. The RS content of cooked WS were affected by the internally structures, particularly lipid content (11.46 % - 19.09 %) in BWS outer layers and amylose content (13.59 % - 19.43 %) in the inner layers. These results revealed the internal radial structural differences and digestibility patterns of AWS and BWS granules.

The role of non-starch constituents in the extrusion processing of slow-digesting starch diets: A review

Starch is the main source of energy for the human body through diet, and its digestive properties are closely related to the occurrence of chronic diseases. Extrusion technology, which is characterized by low cost and high efficiency, has been widely used in the field of reducing starch digestibility and modifying starch, and it has great potential for designing and manufacturing precision nutrition for specific populations. However, this aspect of study has not been systemically summarized, so we systematically discuss the role of extrusion and non-starch components in starch modification in this review. This review focuses on the following sections: the effect mechanisms of extrusion on starch digestibility in terms of granule morphology, crystal structure, viscosity and pasting characteristics; the different effects of single or multiple non-starch components on starch digestibility under extrusion; and some of the current applications of extrusion technology in the development of slow-digesting starchy diets. This review summarises the effects of extrusion techniques and non-starch components on starch digestibility under extrusion conditions, and provides the appropriate theoretical basis for the application of starch-based foods in the development of slow-digesting diets, the precise nutritional design of specific populations, and the improvement of the structure of healthy human diets.

Study on the Mechanism of Effect of Protein on Starch Digestibility in Fermented Barley

Previous studies have shown that fermented barley has a lower digestion rate. However, it remains unclear whether the antidigestibility of starch in fermented barley is affected by other nonstarch components. In this paper, the removal of protein, lipid, and β-glucan improved the hydrolysis rate of starch and the protein showed the greatest effect. Subsequently, the inhibitory mechanism of protein on starch digestion was elucidated from the perspective of starch physicochemical properties and structural changes. The removal of protein increased the swelling power of starch from 10.09 to 11.14%. The short-range molecular ordered structure and the helical structure content decreased. The removal of protein reduced the coating and particle size of the starch particles, making the Maltese cross more dispersed. In summary, protein in fermented barley enhanced the ordered structure of starch by forming a physical barrier around starch and prevented the expansion of starch, which inhibited the hydrolysis of starch.

Impact of Rice Bran Oil Emulsified Formulation on Digestion and Glycemic Response to Japonica Rice: An In Vitro Test and a Clinical Trial in Adult Men

To assess the effect of rice bran oil emulsified formulation (EMF) on cooked rice, a single-arm open clinical trial and in vitro testing for digestion and glycemic response were performed. Fifteen Japanese men consumed 200 g of packed rice, cooked with or without EMF. Blood samples were collected 0, 30, 60, and 120 min post-consumption and analyzed for glucose, insulin, and triglyceride levels. Continuous glucose monitoring (CGM) and sensory evaluation were also performed. A two-step in vitro digestion test, simulating gastric and small intestinal digestion was conducted. EMF-added rice group showed higher insulin response levels at 60 min than the placebo group. Stratification of participants with HbA1c ≥ 5.6 or an insulinogenic index ≤ 0.4 revealed a significant reduction in Cmax glucose levels. A significant correlation was observed between venous and CGM blood glucose levels and no significant sensory differences were observed. The in vitro test revealed significantly lower C∞, equilibrium starch concentrations, with EMF. Clinical trial suggests that EMF may stimulate insulin secretion and reduce blood glucose levels in participants with lower insulin responses. In vitro tests suggest that EMF inhibits glycemic digestion. This trial was registered at the UMIN Center (UMIN000053495; registered 31 January 2024).

Food Matrix Composition Affects the Allergenicity of Baked Egg Products

BACKGROUND

Egg allergy is common and caused by sensitization to ovomucoid and/or ovalbumin. Many egg-allergic patients are able to tolerate eggs baked into other foods, such as muffins. Although heating egg extensively reduces allergens, the effect of other food ingredients on allergenicity of eggs, or the "matrix effect," is less well studied.

OBJECTIVE

We aimed to define how food matrices impact the matrix effect in egg allergenicity.

METHODS

Enzyme-linked immunosorbent assay was used to quantify ovalbumin and ovomucoid in extracts from various baked egg products: plain baked egg without a matrix, and muffins baked using either wheat flour, rice flour, or a wheat flour/banana puree mix. Allergen-specific immunoglobulin E (IgE)-blocking enzyme-linked immunosorbent assays were performed using the egg product extracts on egg-allergic patient sera to determine whether the amount of extracted egg protein in each extract correlated with how well the extracts could bind patients' egg IgE.

RESULTS

Baking eggs in any muffin matrix led to an increase in the amount of extractable ovalbumin and a decrease in the amount of extractable ovomucoid compared with plain baked egg. Compared with wheat muffins, rice muffins had more extractable ovalbumin and wheat/banana muffins had more extractable ovalbumin and ovomucoid. The egg allergens in the extracts were able to block egg-allergic patients' egg IgE.

CONCLUSIONS

Food matrices affect egg allergen availability. Patients and families should be advised that substitutions in baked egg muffin recipes can affect the amount of egg allergens in foods and potentially affect the risk of food allergic reaction.

Insight into the promoted recrystallization and water distribution of bread by removing starch granule - surface and - associated proteins during storage

The influence of starch granule surface proteins (SGSPs) and starch granule-associated proteins (SGAPs) on bread retrogradation was investigated in a reconstituted dough system. The removal of both SGSPs and SGAPs resulted in poor bread qualities, decreasing specific volume and crumb porosity, leading to more baking loss and compact crumb structure. Particularly, removing SGSPs was effective in promoting the bread retrogradation. After 7 days of storage, the hardness of bread without SGSPs showed an increase of 353.34 g than the bread without SGAPs. Proton population and relaxation times exhibited that the absence of SGSPs significantly decreased the content of bound water from 11.51 % to 7.03 %, indicating lower water-holding capacity due to the loosen gelling structure. Compared to the control group, bread without SGSPs accelerated the starch recrystallinity by a reduction in soluble starch content, thereby increasing the retrogradation enthalpy and relative crystallinity through promoting the molecular reassociation in starch.

Strategic exploration of whole grain cereals in modulating the glycaemic response

In the current context, diabetes presents itself as a widespread and complex global health issue. This study explores the significant influence of food microstructure and food matrix components interaction (protein, lipid, polyphenols, etc.) on the starch digestibility and the glycaemic response of post-prandial glycemia, focusing on the potential effectiveness of incorporating bioactive components from whole grain cereals into dietary strategies for the management and potential prevention of diabetes. This study aims to integrate the regulation of postprandial glycaemic homeostasis, including the complexities of starch digestion, the significant potential of bioactive whole grain components and the impact of food processing, to develop a comprehensive framework that combines these elements into a strategic approach to diabetes nutrition. The convergence of these nutritional strategies is analyzed in the context of various prevalent dietary patterns, with the objective of creating an accessible approach to mitigate and prevent diabetes. The objective remains to coalesce these nutritional paradigms into a coherent strategy that not only addresses the current public health crisis but also threads a preventative approach to mitigate future prevalence and impact.

Effects of protein morphological structures on the cereal processing, sensorial property and starch digestion: a review

In cereals, the protein body and protein matrix are usually two morphological protein structures. However, processing treatments can affect protein structures, change protein bodies into the matrix, or induce a change in the matrix structure; therefore, the processing-induced matrix was listed as the third morphological structure of the protein. Previous research on the effect of proteins was mainly based on protein content and composition, but these studies arrived at different conclusions. Studying the effect of protein morphological structures on sensorial property and starch digestion can provide a theoretical basis for selecting cultivars with high sensorial property and help produce low-glycemic index foods for people with diabetes, controlling their postprandial blood sugar. This study aimed to review the distribution and structure of protein bodies, protein matrices, and processing-induced matrices, as well as their influence on cereal sensorial property and starch digestion. Therefore, we determined the protein morphological structures in different cereal cultivars and summarized its impact. Protein bodies mainly have steric stabilization effects on starch gelatinization, whereas the protein matrix serves as a physical barrier surrounding the starch to inhibit water absorption and α-amylase. Processing can change protein morphological structures, enabling protein bodies to act as a physical matrix barrier.

Functional foods with a tailored glycemic response based on food matrix and its interactions: Can it be a reality?

Functional foods are considered the future of nutrition because they benefit human health and environmental sustainability. They offer natural solutions for managing post-prandial glycemia and its long-term consequences. Therefore, understanding the composition and inherent dynamics of the functional food matrix (FM) is crucial. Within the FM, components like proteins, fats, carbohydrates, phenolic compounds, fibres, and minor elements interact dynamically, highlighting how individual components within the system behave. This review highlights the significance of diverse FM interactions in modulating inherent glycemic potential (IGP). These interactions comprise major binary, ternary, quaternary interactions, and minor interactions, in contemporary functional food formulations that include starch-derived additives, biopeptides, and flavouring agents. The starch quality matrix (SQM), a prediction model for customised functional foods with low IGP, has been briefed as a pilot concept. We also investigate the impact of these interactions on gut health, fill in the knowledge gaps, and provide recommendations for further study.

A review of endogenous non-starch components in cereal matrix: spatial distribution and mechanisms for inhibiting starch digestion

As compared with exogenous components, non-starch components (NSCS), such as proteins, lipids, non-starch polysaccharides (NSPs), and polyphenols, inherently present in cereals, are more effective at inhibiting starch digestibility. Existing research has mostly focused on complex systems but overlooked the analysis of the in-situ role of the NSCS. This study reviews the crucial mechanisms by which endogenous NSCS inhibit starch digestion, emphasizing the spatial distribution-function relationship. Starch granules are filled with pores/channels-associated proteins and lipids, embedding in the protein matrix, and maintained by endosperm cell walls. The potential starch digestion inhibition of endogenous NSCS is achieved by altering starch gelatinization, molecular structure, digestive enzyme activity, and accessibility. Starch gelatinization is constrained by endogenous NSCS, particularly cell wall NSPs and matrix proteins. The stability of the starch crystal structure is enhanced by the proteins and lipids distributed in the starch granule pores and channels. Endogenous polyphenols greatly inhibit digestive enzymes and participate in the cross-linking of NSPs in the cell wall space, which together constitute a physical barrier that hinders amylase diffusion. Additionally, the spatial entanglement of NSCS and starch under heat and non-heat processing conditions reduces starch accessibility. This review provides novel evidence for the health benefits of whole cereals.

Influence of key component interactions in flour on the quality of fried flour products

In the field of food, the interaction between various components in food is commonly used to regulate food quality. Starches, proteins, and lipids are ubiquitous in the food system and play a critical role in the food system. The interaction between proteins, starches, and lipids components in flour is the molecular basis for the formation of the classical texture of dough, and has a profound impact on the processing properties of dough and the quality of flour products. In this article, the composition of the key components of flour (starch, protein and lipid) and their functions in dough processing were reviewed, and the interaction mechanism of the three components in the dynamic processing of dough from mixing to rising to frying was emphatically discussed, and the effects of the components on the network structure of dough and then on the quality of fried flour products were introduced. The analysis of the relationship between dough component interaction, network structure and quality of fried flour products is helpful to reveal the common mechanism of quality change of fried flour products, and provide a reference for exploring the interaction of ingredients in starch food processing.

In vitro digestibility of starch and protein in cooked wheat and oat whole flours: A comparative study

Whole grains have garnered significant attention in the food industry due to their retained abundant nutrients when compared to refined grains. However, limited knowledge exists regarding the digestive behavior of starch and protein. This study compared the physicochemical properties and in vitro starch and protein digestibility of cooked whole wheat flour (WF) and naked oat flour (NOF), and evaluated the impact of endogenous components (protein, lipid, β-glucan, and polyphenol) on the physicochemical properties and digestibility of WF and NOF. The result indicated that the final hydrolysis rate of WF samples (starch: 23.2 %∼46.3 %; protein: 23.1 %∼63.0 %) was lower than that of NOF samples (starch: 32.1 %∼61.0 %; protein: 32.3 %∼63.6 %). The removal of different endogenous components led to improved digestibility of starch and protein in both WF and NOF. This study contributes to the understanding of the starch and protein digestibility of whole grains, consequently facilitating the development of whole grain products.

Antioxidant Activity, Glycemic Response, and Functional Properties of Rice Cooked with Red Palm Oil

High rice consumption levels accompanied by a lifestyle lacking in physical activity leads to obesity and diabetes due to the rice consumed generally has high digestibility and high glycemic index. Red palm oil (RPO) is a vegetable oil suggested to have the potential to reduce starch digestibility and increase the bioactive compounds of rice. This research aimed to find out the best cooking method to produce rice with a sensory quality similar to regular rice and to study the effect of the best cooking method on the glycemic response and physicochemical properties of rice. The results showed that RPO addition increased the antioxidant activities and total carotenoid levels of rice. The addition of RPO after cooking has better antioxidant activity and total carotenoid than before cooking. Adding 2% RPO before or after cooking produced rice with similar or better sensory quality than regular rice. Rice cooked with 2% RPO added before cooking had a lower glycemic response than regular rice, which was suggested to be caused by the increasing formation of the amylose lipid complex and the triglycerides that protected the starch from amylase enzyme. The formation of the amylose lipid complex and triglyceride layers protecting rice starch was confirmed by the new peaks of the FTIR spectra, the appearance of oil-coated starch morphology, and the changes in the proportion of C and O atoms. In conclusion, the addition of 2% RPO before the cooking process can be considered as a cooking method to produce rice for diabetic patients.

Effect of emulsified lipid and saponified lipid on the enzyme desizing of starch and its mechanism

To enhance the flexibility of starch film adhesion on yarns, sizing lipids (saponified lipid or emulsified lipid) must be added during the sizing process. However, different types of sizing lipids may have diverse combinations with starch to impact enzyme desizing. Therefore, this study investigated the effects of saponified lipid and emulsified lipid commonly used in warp sizing on the hydrolysis of starch. Additionally, the desizing efficiency and chain structure of desizing residues were analyzed. Experimental results demonstrated that the existence of saponified lipid or emulsified lipid led to a reduction in the degree of hydrolysis (1.1 % and 2.6 %, respectively) compared to the original corn starch. Notably, saponified lipid exhibited a relatively strong negative impact. Furthermore, the desizing efficiency decreased after adding emulsified lipid (1.2 %) or saponified lipid (2.9 %). Starch-lipid V-type complexes and physical hindrance could inhibit the enzyme desizing, resulting in a larger wavelength of maximum absorbance for desizing residues, along with higher molecular weight, z-average radius of gyration, and an increased proportion of long chains. The presence of saponified lipid significantly negatively influenced desizing, possibly due to the smaller particle size and propensity for complex formation with starch.

Rheological, thermal, and in vitro starch digestibility properties of oat starch-lipid complexes

The influence of oat lipids on the structural, thermal, rheological, and in vitro digestibility properties of oat starch under heat processing conditions was investigated. X-ray diffraction, fourier infrared spectroscopy, and differential scanning calorimetry revealed the formation of a V-shaped crystal structure between starch and lipid, resulting in enhanced orderliness and enthalpy. Oat lipids decreased the final viscosity and gel strength of oat starch while weakening the trend towards gel network formation. Additionally, oat lipids exhibited enhanced resistance to starch hydrolase, leading to elevated contents of slowly digestible starch and resistant starch. Consequently, this leads to an augmentation in the rate constants for the rapid digestion fraction (k1) and the slow digestion fraction (k2). When the lipid content reached 7.50 %, a significant increase of 42.20 % was observed in the maximum digestibility of slow digestion fraction (C∞2), while a notable decrease of 44.06 % was noted in the maximum digestibility of rapid digestion fraction (C∞1). The correlation analysis revealed that lipid content, final viscosity, and enthalpy exerted significant influences on in vitro starch digestion. These results demonstrate the substantial impact of lipid content on oat starch structure, subsequently affecting its thermal, rheological, and digestive properties.

Effect of endogenous protein and lipid removal on the physicochemical and digestion properties of sand rice (Agriophyllum squarrosum) flour

The study investigated the effect of removing protein and/or lipid on the physicochemical characteristics and digestibility of sand rice flour (SRF). Morphological images showed that protein removal had a greater impact on exposing starch granules, while lipids acted as an adhesive. The treatment altered starch content in SRF samples, leading to increased starch crystallinity, denser semi-crystalline region, lower onset gelatinization temperature (To), higher peak viscosity and gelatinization enthalpy (ΔH), where Protein removal showed a more pronounced effect on altering physicochemical properties compared to lipid removal. The research revealed a positive correlation between rapidly digestible starch (RDS), maximum degree of starch hydrolysis (C∞), digestion rate constant (k) values and 1047/1022 cm-1 ratio, showing a strong connection between short-range structure and starch digestibility. The presence of endogenous proteins and lipids in SRF hinder digestion by restricting starch swelling and gelatinization, and physically obstructing enzyme-starch interaction. Lipids had a greater impact on starch digestibility than proteins, possibly due to their higher efficacy in reducing digestibility, higher lipid content with greater potential to form starch-lipid complexes. This study provides valuable insights into the interaction between starch and proteins/lipids in the sand rice seed matrix, enhancing its applicability in functional and nutritional food products.

Effect of steam explosion modified soluble dietary fiber from Tremella fuciformis stem on the quality and digestibility of biscuits

Steam explosion (SE) technology is an effective modification method for improving resource utilization of edible fungi processing by-products. In this study, the effect of SE-modified Tremella fuciformis (T. fuciformis) stem soluble dietary fiber (SDF) on the quality and digestibility of biscuits was investigated. The results showed that the addition of SE-modified T. fuciformis stem SDF (M-SDF) changed the gluten network structure and moisture distribution in the biscuits, which improved the spread ratio of the biscuits and resulted in attractive colors. Meanwhile, as starch was embedded, the starch hydrolysis rate (from 60.9 ± 0.90 % to 43.01 ± 0.78 %) and estimated glycemic index (from 84.10 ± 4.39 to 68.45 ± 3.15) of 12 % M-SDF biscuits were reduced. Furthermore, 8 % M-SDF received the highest sensory scores. These results demonstrate the potential applicability of SE-modified edible fungi processing by-product SDF as an additive in functional foods.

The impact of different soluble endogenous proteins and their combinations with β-glucan on the in vitro digestibility, microstructure, and physicochemical properties of highland barley starch

The impacts of protein types and its interaction with β-glucan on the in vitro digestibility of highland barley starch were investigated through analyzing physicochemical and microstructural properties of highland barley flour (HBF) after sequentially removing water- (WP), salt- (SP), alcohol- (AP) and alkali-soluble (AlkP) proteins. Resistant starch (RS) increased significantly in HBF after removing WP and SP, and RS of HBF was lower than that of without β-glucan. After removing WP, SP and AP, swelling powers of HBF without β-glucan (9.33-9.77) were higher than those of HBF (12.09-15.95). Trends of peak viscosity and peak temperature (thermal degradation temperature) were similar as swelling power, and HBF without AP showed the highest peak temperature (310.33 °C). Removals of different proteins improved the crystalline structure and short-range order of starch. There was a blue shift in T2 values and an opposite change in free water proportion. The matrix on starch surface was mainly formed by AP and AlkP, which could be aggregated by β-glucan. But, the inhibitory effect of AP or AlkP was stronger than that of proteins combined with β-glucan. These results help in the development of starch-based foods with different digestive properties by combining different protein types with β-glucan.

New Insight into the Effects of Endogenous Protein and Lipids on the Enzymatic Digestion of Starch in Sorghum Flour

The effects of endogenous lipids and protein in sorghum flour on starch digestion were studied following the depletion of lipids and/or protein and after the reconstitution of separated fractions. The removal of protein or lipids moderately increases the digestibility of starch in raw (uncooked) sorghum flour to values close to those for purified starch. Rapid Visco Analyzer data (as a model for the cooking process) show that cooked sorghum flours with lipids have a lower starch digestibility than those without lipids after RVA processing, due to the formation of starch-lipid complexes as evidenced by their higher final viscosity and larger enthalpy changes. Additionally, the formation of a starch-lipid-protein ternary complex was identified in cooked sorghum flour, rather than in a reconstituted ternary mixture, according to the unique cooling stage viscosity peak and a greater enthalpy of lipid complexes. After heating, the sorghum flour showed a lower digestibility than the depleted flours and the reconstituted flours. The results indicate that the natural organization of components in sorghum flour is an important factor in facilitating the interactions between starch, lipids, and protein during RVA processing and, in turn, reducing the starch digestion.

Impact of Cooking Methods on Phenolic Acid Composition, Antioxidant Activity, and Starch Digestibility of Chinese Triticale Porridges: A Comparative Study between Atmospheric Pressure and High Pressure Boiling

Water boiling under atmospheric pressure (CAP) and water boiling under high pressure (CHP) are two popular domestic cooking methods for Chinese porridge making. In this study, we aimed to evaluate the effects of these two methods on the phenolic acid composition, antioxidant activity, and starch digestibility of triticale porridges. The contents of total free and total bound phenolic acids in the CHP sample were 1.3 and 1.6 times higher than those in the CAP counterpart, respectively, although the DPPH and ABTS values of these two samples were comparable. CAP induced more small pieces of starch than CHP, and the gelatinization enthalpy was 19% higher in the CHP sample than that in the CAP. Both cooking methods increased the starch digestibility, while the CHP sample (58.84) showed a lower GI than the CAP (61.52). These results may promote the application of triticale in health-promoting staple foods.

Inhibition mechanism of rice glutelin on extruded starch digestion: From the structural properties of starch and enzyme activity

To increase the anti-digestion ability of extruded rice starch (ERS), the influence of rice glutelin (RG) on digestive and structural characteristics of ERS were investigated. The resistant starch content increased from 4.49 % to 18.08 % as the RG content increased, while the digestion rate and digestion velocity constant were reduced by the incorporation of RG. Morphological observations showed that ERS was adhered and encapsulated by RG, and the specific area of starch granules were decreased after the addition of RG. The results of XRD and FTIR suggested that the long-range and short-range orders of ERS were improved due to the complexation with RG. The thickness of crystalline of ERS was increased while its amorphous region thickness was reduced by the supplementation with RG. The 1H NMR and 13C NMR data revealed that the branching degree and double helix content of ERS was increased by 46.24 % and 52.67 % when RG content reached to 12 %. Additionally, the addition of RG altered the molecular weight and chain length distribution of ERS. The α-amylase activity and glucoamylase activity was inhibited by RG. These results could provide a valuable basis for the application of RG in extruded rice starchy foods with lower glycemic index.

Effect of non-starch components on the structural properties, physicochemical properties and in vitro digestibility of waxy highland barley starch

Highland barley (HB) endosperm with an amylose content of 0-10 % is called waxy HB (WHB). WHB is a naturally slow-digesting grain, and the interaction between its endogenous non-starch composition and the WHB starch (WHBS) has an important effect on starch digestion. This paper focuses on the mechanisms by which the components of β-glucan, proteins and lipids affect the molecular, granular, crystalline structure and digestive properties of WHBS. After eliminating the main nutrients except for starch, the estimated glycemic index (eGI) of the samples rose from 62.56 % to 92.93 %, and the rapidly digested starch content increased from 60.81 % to 98.56 %, respectively. The resistant starch (RS) content, in contrast, dropped from 38.61 % to 0.13 %. Comparatively to lipids, β-glucan and protein contributed more to the rise in eGI and decline in RS content. The crystalline characteristics of starch were enhanced in the decomposed samples. The samples' gelatinization properties improved, as did the order of the starch molecules. Protein and β-glucan form a dense matrix on the surface of WHBS particles to inhibit WHBS digestion. In summary, this study revealed the mechanism influencing the digestibility of WHBS from the perspective of endogenous non-starch composition and provided a theoretical basis to develop slow-digesting foods.

Assessing the Postprandial Glycemic Response to Japonica Rice (Oryza sativa L. cv. Koshihikari) with a Small Amount of Lysolecithin and Canola Oil in Japanese Adult Men: a Double-blind, Placebo-controlled, Crossover Study

A double-blind, placebo-controlled, crossover trial was performed to analyze the effects of a small amount of lysolecithin and canola oil on blood glucose levels after consuming japonica rice. Overall, 17 Japanese adult men were assigned to consume 150 g of normally cooked japonica rice (placebo group) and 150 g of japonica rice cooked with 18 mg of lysolecithin and 1.8 g of canola oil (treatment group); these lipids were added as emulsified formulation (EMF) for stability and uniformity. Subsequently, blood samples were collected before and 30, 45, 60, 90, and 120 min after consuming test foods. There was no significant difference in blood glucose, insulin, and triglyceride levels between the groups. However, a stratified analysis of 11 subjects with body mass index (BMI) ≥ 22 revealed that blood glucose levels were significantly lower after 30 min in the treatment group than in the placebo group (p = 0.041). Through in vitro digestibility test, the rice sample of the treatment group was observed to release significantly less glucose within 20 min than that in the placebo group rice. These results suggest that the combination of a small amount of lysolecithin and canola oil modulated the increase in postprandial blood glucose levels induced by the intake of cooked japonica rice in adult men with BMI ≥ 22. This clinical trial was registered with the University Hospital Medical Information Network (UMIN) Center, (UMIN000045744; registered on 15/10/2021).

Effects of peanut oligopeptides on the pasting properties of potato starch and digestive characteristics of dry, flat potato starch noodles

In this study, we developed dry, flat potato starch noodles with an ideal taste and low digestibility. Peanut oligopeptide and potato starch were combined to form dry, flat potato starch noodles containing different peanut oligopeptide contents using a steam-slice method. Adding 5 % and 10 % peanut oligopeptides maintained the dry, flat starch noodles' quality. Scanning electron microscopy (SEM) analysis showed that dry, flat starch noodles containing peanut oligopeptides had more pores with pore sizes ranging from 0.30 μm to 2.00 μm. X-ray diffraction (XRD) results showed that peanut oligopeptide promoted the recrystallization of amylopectin during the retrogradation process after gelatinization, and the crystallinity of noodles ranged from 4.31 % (control noodles) to 18.24 % (noodles containing 10 % peanut oligopeptides). An in vitro simulated digestion test showed that the slowly digestible starch and resistant starch contents of noodles containing 10 % peanut oligopeptides were 18.24 % and 22.03 %-significantly higher than control starch noodles (14.88 % and 9.9 %, respectively). Therefore, when peanut oligopeptides were added to dry, flat starch noodles, it was a promising material for lowering blood sugar levels after meals.

The differences in metabolites, starch structure, and physicochemical properties of rice were related to the decrease in taste quality under high nitrogen fertilizer application

Nitrogen fertilizer application is one of the key cultivation practices to improve rice yields. However, the application of high nitrogen fertilizers often leads to a reduction in the stickiness of the rice after cooking, thus reducing the taste quality of rice. Moreover, there are differences in taste quality among rice varieties, and the mechanism has not been studied in depth. In this study, two rice varieties (Meixiangzhan2hao and Exiang2hao) were planted under two nitrogen fertilizer levels. The physicochemical properties and taste quality of the rice were determined after maturity. Our results showed that high nitrogen fertilizer level alters tryptophan metabolism in rice, increasing most amino acid content and protein content in rice. The high content of protein and the higher short-range ordered structure of starch inhibited the gelatinization characteristics of starch and reduced the taste quality of rice. Under high nitrogen fertilizer application, Exiang2hao showed smaller increases in protein content, lower level of amylose and relative crystallinity, and higher content of lipid metabolites. These differences in chemical substances resulted in a less pronounced reduction in the taste quality of Exiang2hao. In this study, the taste quality of different rice varieties under different levels of nitrogen fertilizer application was analyzed, providing new ideas for future improvement of rice taste quality.

A review of starch swelling behavior: Its mechanism, determination methods, influencing factors, and influence on food quality

Swelling behavior involves the process of starch granules absorbing enough water to swell and increase the viscosity of starch suspension under hydrothermal conditions, making it one of the important aspects in starch research. The changes that starch granules undergo during the swelling process are important factors in predicting their functional properties in food processing. However, the factors that affect starch swelling and how swelling, in turn, affects the texture and digestion characteristics of starch-based foods have not been systematically summarized. Compared to its long chains, the short chains of amylose easily interact with amylopectin chains to inhibit starch swelling. Generally, reducing the swelling of starch could increase the strength of the gel while limiting the accessibility of digestive enzymes to starch chains, resulting in a reduction in starch digestibility. This article aims to conduct a comprehensive review of the mechanism of starch swelling, its influencing factors, and the relationship between swelling and the pasting, gelling, and digestion characteristics of starch. The role of starch swelling in the edible quality and nutritional characteristics of starch-based foods is also discussed, and future research directions for starch swelling are proposed.

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

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

Modulating the glycemic response of starch-based foods using organic nanomaterials: strategies and opportunities

Traditionally, diverse natural bioactive compounds (polyphenols, proteins, fatty acids, dietary fibers) are used as inhibitors of starch digestive enzymes for lowering glycemic index (GI) and preventing type 2 diabetes mellitus (T2DM). In recent years, organic nanomaterials (ONMs) have drawn a great attention because of their ability to overcome the stability and solubility issues of bioactive. This review aimed to elucidate the implications of ONMs in lowering GI and as encapsulating agents of enzymes inhibitors. The major ONMs are presented. The mechanisms underlying the inhibition of enzymes, the stability within the gastrointestinal tract (GIT) and safety of ONMs are also provided. As a result of encapsulation of bioactive in ONMs, a more pronounced inhibition of enzymes was observed compared to un-encapsulated bioactive. More importantly, the lower the size of ONMs, the higher their inhibitory effects due to facile binding with enzymes. Additionally, in vivo studies exhibited the potentiality of ONMs for protection and sustained release of insulin for GI management. Overall, regulating the GI using ONMs could be a safe, robust and viable alternative compared to synthetic drugs (acarbose and voglibose) and un-encapsulated bioactive. Future researches should prioritize ONMs in real food products and evaluate their safety on a case-by-case basis.

The effect of heat-moisture treatment changed the binding of starch, protein and lipid in rice flour to affect its hierarchical structure and physicochemical properties

This study investigated the effect of removing proteins, lipids and starch on the structure, physicochemical properties and digestion properties of rice flour (with 30% moisture) treated with heat moisture treatment (HMT). According to the results, HMT caused the adhesion and agglomeration of the rice flour, promoted the binding between starch, protein and lipid molecular chains and led to the formation of complexes (especially starch-lipid complexes), which hindered the removal of non-starch components. Compared to the untreated rice flour, the HMT treated lipid-removal rice flour had small changes in their crystallinity, gelatinization temperature and viscosity property. After removing protein, the crystallinity, peak viscosity, final viscosity, breakdown and starch digestibility were sharply increased. In particular, the peak viscosity increased from 811 cP to 1746 cP and the enthalpy change increased from 5.33 J/g to 10.18 J/g. These findings are helpful in understanding the contribution of removing endogenous proteins and lipids to the physicochemical changes of HMT treated rice flour during its heating process and thus can be helpful in controlling the quality of rice flour through HMT.

Insights into Recent Updates on Factors and Technologies That Modulate the Glycemic Index of Rice and Its Products

Rice is a staple food and energy source for half the world's population. Due to its quick digestion and absorption in the gastrointestinal tract, rice is typically regarded as having a high or medium-high glycemic index (GI); however, this can vary depending on the variety, nutrient compositions, processing, and accompanying factors. This report included a table of the glycemic index for rice and rice products in different countries, which could give an overview and fundamental information on the recent GI of different rice varieties. In addition, latest updates about the mechanism effects of rice nutritional profiles and processing techniques on GI were also provided and discussed. The influence of state-of-the-art GI regulation methods was also evaluated. Furthermore, the effectiveness and efficiency of applied technologies were also given. Furthermore, this review offered some aspects about the potential nutraceutical application of rice that food scientists, producers, or consumers might consider. Diverse types of rice are grown under various conditions that could affect the GI of the product. The instinct nutrients in rice could show different effects on the digestion rate of its product. It also revealed that the rice product's digestibility is process-dependent. The postprandial glucose response of the rice products could be changed by modifying processing techniques, which might produce the new less-digestive compound or the inhibition factor in the starch hydrolysis process. Because of the significant importance of rice, this paper also concluded the challenges, as well as some important aspects for future research.

Effect of protein on the gelatinization behavior and digestibility of corn flour with different amylose contents

The effects of endogenous proteins on the gelatinization behavior and digestibility of waxy corn flour (WCF), normal corn flour (NCF) and high amylose corn flour (HCF) were systematically investigated. Microscopic characteristics showed that the proteins surrounded multiple starch granules, which led to an increase in the particle size of the corn flour, but no significant change in the relative crystallinity. Small angle x-ray scattering experiments during pasting revealed that the starch granules of NCF remained compact, while WCF and HCF were relatively loose. Carbon-13 nuclear magnetic resonance spectroscopy (13C NMR) showed that the proteins retained the helical structure of starch allowing NCF to have a higher Resistant starch(RS) content. The presence of protein led to a decrease in swelling power, viscosity, and in vitro digestibility of starch, and a noticeable increase in gelatinization temperature and thermal stability. RS increased most significantly in NCF from 3.86 % to 15.27 %. The effect of protein on the water activity of starch with different amylose contents after pasting was also inconsistent. This study will contribute to the understanding of the interaction between starch and protein in corn flours with different amylose contents and contribute to the development of corn flours.

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.

Mining nutri-dense accessions from rice landraces of Assam, India

The Indian subcontinent is the primary center of origin of rice where huge diversity is found in the Indian rice gene pool, including landraces. North Eastern States of India are home to thousands of rice landraces which are highly diverse and good sources of nutritional traits, but most of them remain nutritionally uncharacterized. Hence, nutritional profiling of 395 Assam landraces was done for total starch, amylose content (AC), total dietary fiber (TDF), total protein content (TPC), oil, phenol, and total phytic acid (TPA) using official AOAC and standard methods, where the mean content for the estimated traits were found to be 75.2 g/100g, 22.2 g/100g, 4.67 g/100g, 9.8 g/100g, 5.26%, 0.40 GAE g/100g, and 0.34 g/100g for respectively. The glycaemic index (GI) was estimated in 24 selected accessions, out of which 17 accessions were found to have low GI (<55). Among different traits, significant correlations were found that can facilitate the direct and indirect selection such as estimated glycemic index (EGI) and amylose content (-0.803). Multivariate analyses, including principal component analysis (PCA) and hierarchical clustering analysis (HCA), revealed the similarities/differences in the nutritional attributes. Four principal components (PC) i.e., PC1, PC2, PC3, and PC4 were identified through principal component analysis (PCA) which, contributed 81.6% of the variance, where maximum loadings were from protein, oil, starch, and phytic acid. Sixteen clusters were identified through hierarchical clustering analysis (HCA) from which the trait-specific and biochemically most distant accessions could be identified for use in cultivar development in breeding programs.

The antioxidant capacity and nutrient composition characteristics of lotus (Nelumbo nucifera Gaertn.) seed juice and their relationship with color at different storage temperatures

The effects of different storage temperatures on the nutritional quality, color, and antioxidant capacity of lotus seed juice and the correlations between various physicochemical indices and antioxidant capacity during storage were investigated in this study. The results showed that the overall retention rate of various nutrients and antioxidant activity in lotus seed juice under low-temperature storage was better than that under 37 °C storage. Meanwhile, temperature had a significant effect on increasing the browning of lotus seed juice and the change in L*. The results of Pearson correlation and redundancy analysis (RDA) showed that the reduction in antioxidant activity in lotus seed juice aggravated the browning index of the system at high temperatures. The color changes in the system were closely related to the clarity of lotus seed juice and aging of starch at low temperatures.

Impacts of Inherent Components and Nitrogen Fertilizer on Eating and Cooking Quality of Rice: A Review

With the continuous improvement of living standards, the preferences of consumers are shifting to rice varieties with high eating and cooking quality (ECQ). Milled rice is mainly composed of starch, protein, and oil, which constitute the physicochemical basis of rice taste quality. This review summarizes the relationship between rice ECQ and its intrinsic ingredients, and also briefly introduces the effects of nitrogen fertilizer management on rice ECQ. Rice varieties with higher AC usually have more long branches of amylopectin, which leach less when cooking, leading to higher hardness, lower stickinesss, and less panelist preference. High PC impedes starch pasting, and it may be hard for heat and moisture to enter the rice interior, ultimately resulting in worse rice eating quality. Rice with higher lipid content had a brighter luster and better eating quality, and starch lipids in rice have a greater impact on rice eating quality than non-starch lipids. The application of nitrogen fertilizer can enhance rice yield, but it also decreases the ECQ of rice. CRNF has been widely used in cereal crops such as maize, wheat, and rice as a novel, environmentally friendly, and effective fertilizer, and could increase rice quality to a certain extent compared with conventional urea. This review shows a benefit to finding more reasonable nitrogen fertilizer management that can be used to regulate the physical and chemical indicators of rice grains in production and to improve the taste quality of rice without affecting yield.

The Microstructure, Rheological Characteristics, and Digestibility Properties of Binary or Ternary Mixture Systems of Gelatinized Potato Starch/Milk Protein/Soybean Oil during the In Vitro Digestion Process

The in vitro digestibility of potato starch-based foods interacting with milk protein and soybean oil was investigated. Microstructures and rheological changes upon digestion were determined. The results showed that the addition of milk proteins (casein and whey protein) promoted gelatinized potato starch digestion, while soybean oil slowed down gelatinized potato starch digestion. A mixture of soybean oil and milk protein promoted the digestion of milk protein, while a mixture of gelatinized potato starch and milk protein inhibited the digestion of milk protein. The mixture of milk protein and/or gelatinized potato starch with soybean oil promoted the release of free fatty acids in soybean oil. The highest release rate of free fatty acids was attained by a mix of milk protein and soybean oil. The mixed samples were digested and observed with a confocal laser scanning microscope. The viscosity of the digestates was determined by a rheometer. Overall, the results demonstrated that the addition of milk protein and soybean oil had an effect on the in vitro digestibility of gelatinized potato starch and its microstructure.

Influence of instant rice characteristics and processing conditions on starch digestibility-A review

Instant rice is increasingly popular around the world due to its convenience, but it commonly has a high glycemic index, and a frequent consumption might contribute to the occurrence of many chronic diseases. In this review, the main factors determining starch digestibility of instant rice were comprehensively evaluated, aiming to help the rice industry develop instant rice with slow starch digestibility. Starch digestibility in instant rice can be reduced by manipulating its intrinsic and extrinsic nutrients. Processing conditions, including pre-gelatinization, storage, and reheating are also important for the starch digestibility of instant rice. Individual differences in terms of glycemic response to the same carbohydrate-based diet should be considered when knowledge is transformed from in vitro method to human conditions. This review contains important information that has the potential to reduce the starch digestibility of instant rice and improve public health.