Onset Gelatinization Temperature Research Articles

Editing of the soluble starch synthase gene MeSSIII-1 enhanced the amylose and resistant starch contents in cassava

Foods with high amylose and resistant starch (RS) contents have great potential to enhance human health. In this study, cassava soluble starch synthase MeSSIII-1 gene mutants were generated using CRISPR/Cas9 system. The results showed that the storage roots of messiii-1 mutants had higher contents of amylose, RS, and total starch than those in CK. The rates of small and large-sized starch granules were increased. Additionally, amylopectin starch in messiii-1 mutants had a higher proportion of medium- and long- chains, and a lower proportion of short-chains than those in CK. The onset, peak, and conclusion temperatures of starch gelatinization in messiii-1 mutants were significantly lower than those in CK, and the peak viscosity, trough viscosity and final viscosity all increased. MeSSIII-1 mutation could increase the contents of sucrose, glucose, and fructose in cassava storage roots. We hypothesize that these soluble sugars serve a dual role: they provide the necessary carbon source for starch synthesis and act as sugar signals to trigger the transcriptional reprogramming of genes involved in starch biosynthesis. This process results in a collective enhancement of amylose, RS, and total starch contents, accompanied by changes in starch granule morphology, fine structure, and physicochemical properties.

Rheological, textural, and pasting properties of A- and B-type wheat starches in relation to their molecular structures

A- and B-type wheat starches have significant differences in rheological, textural, and pasting properties; however, the structure-property relationship is not fully revealed. Herein, the physicochemical characteristics and molecular structures of A- and B-type starches isolated from three wheat varieties with different apparent amylose contents (2.41%–27.93%) were investigated. A-type starches exhibited higher pasting viscosities, relative crystallinity, onset gelatinization temperatures, and enthalpies, while B-type starches had wide gelatinization temperature ranges. B-type starches had lower resistant starch contents than their A-type counterparts, but B-type starches formed more stable gels and had a lower tendency to retrograde, resulting in lower hardness, storage (G′) and loss (G′′) moduli but higher tan δ values. A-type starches had lower contents of short amylose (100 ≤ X < 1000) and amylopectin chains (DP 6–12) than B-type. These findings elucidated the differences in molecular structures between A- and B-type starches, which can contribute to their effective application.

Effect of Protein-Starch Interaction on Rheological, Textural, and Sensory Properties of &lt;i&gt;keropok lekor&lt;/i&gt;

This article considers the effect of protein–starch interaction on the gelling, textural, andsensory properties of keropok lekor used as a fish protein–starch model. A two-level factorial design was employed to analyze the quality and acceptability of different formulations of keropok lekor crackers depending on the ratios of minced fish (MF, 20–50 g (w/w)), sago starch (SS, 10–40 g (w/w)), and water (W, 10–35 g (w/w)). The parameters measured were the onset (T0) and peak (Tp) temperatures of gelatinization, storage modulus (G′), and loss modulus during gelatinization (G″). The samples were rated by a group of 30 panelists during texture profile analysis and sensory evaluation. The most preferred samples had the MF : SS : W ratio of 20 : 10 : 10 and were characterized by the lowest onset and peak temperatures of gelatinization. Therefore, this formulation was singled out as optimal for keropok lekor.

Environment found to explain the largest variance in physical and compositional traits in malting barley grain.

Starch is the most abundant constituent (dry weight) in the barley endosperm, followed by protein. Variability of compositional and potentially related physical traits due to genotype and environment can have important implications for the malting and brewing industry. This was the first study to assess the effects of genotype, environment, and their interaction (G × E) on endosperm texture, protein content, and starch traits corresponding to granule size, gelatinization, content, and composition, using a multi-environment variety trial in California, USA. Overall, environment explained the largest variance for all traits (ranging from 23.2% to 76.5%), except the endosperm texture traits wherein the G × E term explained the largest variance (45.0-86.5%). Our unique method to quantify the proportion of fine and coarse milled barley particles using laser diffraction showed a binomial distribution of endosperm texture. The number of small starch granules varied significantly (P-value < 0.05) across genotypes and environments. We observed negative correlations between total protein content and each of enthalpy (-0.70), total starch content (-0.54), and difference between offset and onset gelatinization temperature (-0.52). Furthermore, amylose to amylopectin ratio was positively correlated to volume of small starch granules (0.36). Our findings indicate that environment played a larger role in influencing the majority of starch-related physical and compositional traits. In contrast, variance in endosperm texture was largely explained by G × E. Maltsters would benefit from accounting for environmental contributions in addition to solely genotype when making sourcing decisions, especially with regards to total protein, total starch, enthalpy, and difference between offset and onset gelatinization temperature. © 2024 Society of Chemical Industry.

Octenylsuccinylation strategy to construct high-amylose maize starch–myristic acid complexes with high thermal stability, complexation efficiency and anti-retrogradation ability

Gelatinizing high-amylose maize starch (HAMSt) requires high temperatures to allow complexation with lipids, making it a challenging process. An octenylsuccinylation method was examined as a part of a strategy to decrease the gelatinization temperature of HAMSt, thereby promoting the complexation between HAMSt and myristic acid (MAc). Octenyl succinic anhydride (OSA) modification of HAMSt reduces the onset gelatinization temperature of HAMSt from 71.63 °C to 66.97 °C. Moreover, as the OSA concentration increased from 2 % to 11 %, the degree of substitution and molecular weights of the esterified HAMSt gradually increased from 0.0069 to 0.0184 and from 0.97 × 106 to 1.17 × 106 g/mol, respectively. Fourier transform infrared analysis indicated that the octenyl-succinate groups were grafted onto the HAMSt chains. The formation of HAMSt–MAc complexes improved the thermal stability of OSA-treated HAMSt (peak temperature increased by 0.11 °C–13.95 °C). Moreover, the diffraction intensity of the V-type peak of the 11 % sample was greater than that of other samples. Finally, the anti-retrogradation ability was in the order of OSA–HAMSt–MAc complexes > HAMSt–MAc complexes > HAMSt. Overall, our results indicate that octenylsuccinylation can be an effective strategy to promote the formation of OSA–HAMSt–MAc complexes and delay starch retrogradation.

Effects of Mineral Elements and Annealing on the Physicochemical Properties of Native Potato Starch

Native potato starch is an excellent carrier of minerals due to its inherent ion exchange capacity. Mineral enrichment not only changes the nutritional value but also influences starch pasting and swelling properties. Hydrothermal treatments like annealing constitute a straightforward and green way to tune functional properties. Here, novel combinations of mineral enrichment and annealing were studied. Ion exchange was readily achieved by suspending starch in a salt solution at room temperature over 3 h and confirmed by ICP-OES. Annealing at 50 °C for 24 h using demineralized water or salt solutions strongly affected pasting, thermal, and swelling properties. The obtained XRD and DSC results support a more ordered structure with relative crystallinity increasing from initially 41.7% to 44.4% and gelatinization onset temperature increasing from 60.39 to 65.94 J/g. Solid-state NMR spectroscopy revealed no detectable changes after annealing. Total digestible starch content decreased after annealing from 8.89 to 7.86 g/100 g. During both ion exchange at room temperature and annealing, monovalent cations promoted swelling and peak viscosity, and divalent cations suppressed peak viscosity through ionic crosslinking. The presented combination allows fine-tuning of pasting behavior, potentially enabling requirements of respective food applications to be met while offering an alternative to chemically modified starches.

Enhanced gelling property and freeze-thaw stability of potato, tapioca and corn starches modified by mild heating in aqueous ethanol solution.

Physically modified starches can be classified as natural ingredients on food labels and clean label products. Thus, the market demand for physically modified starch is increasing. Potato, tapioca and corn starches were physically modified by mild heat treatment in an alcoholic solution to enhance their gelling property and freeze-thaw stability. During mild heating of starch suspension (40% w/w) in 10% ethanol solution at the onset gelatinization temperature, granular swelling of starch occurred, followed by amylose leaching with medication of the surface structure of the starch granules. All treated starches exhibited increased gelatinization and pasting temperatures and decreased breakdown for pasting as a result of improved stability against shear and heat. The treated starches had higher hardness, cohesiveness and springiness of gel than the respective native starches, and these gel properties were more pronounced in potato starch than in tapioca and corn starches. The treated starches showed substantially reduced gel syneresis during freeze-thawing. Physical modification of starch by mild heat treatment in an alcoholic solution substantially improved its gelation ability and freeze-thaw stability. © 2024 Society of Chemical Industry.

Sub-high amylose maize starch: an ideal substrate to generate starch with lower digestibility by fermentation of Qu.

The fermentation of Qu (FQ) is a novel method to modify the properties of starch to expand its application and especially to increase the resistant starch (RS) content. Using waxy maize starch (WMS) as a fermentation substrate can increase the RS content significantly but it may be time consuming and not cost effective due to the almost negligible RS content of WMS. To solve this problem, we hypothesized that sub-high amylose starch (s-HAMS), with an amylose content close to 50% could be an ideal substrate for FQ. The results showed that FQ did not change the shape and the particle size of starch granules, the gelatinization peak (Tp), or the conclusion temperature (Tc), but the slowly digested starch content declined. Rapidly digested starch content fluctuated during FQ and the amylose content decreased within 36 h and then increased. Within 24h, FQ significanlty increased these values: the RS content, relative crystallinity (RC), the ratio of FTIR absorbances at 1047/1022cm-1, the diffraction peak at 19.8° in X-ray diffraction (XRD), and the gelatinization onset temperature (To) increased significantly, within 24 h of FQ. However, after 24 h of fermentation, the RS content, RC, the ratio of FTIR absorbances at 1047/1022 cm-1, and gelatinization enthalpy (ΔH) decreased significantly. Sub-high amylose starch is more suitable for FQ to produce low digestibility starch, and the increase in RS may be due to the formation of 'amylose-lipid' complexes (RS5). © 2024 Society of Chemical Industry.

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.

Non-Traditional Starches, Their Properties, and Applications.

This review paper focuses on the recent advancements in the large-scale and laboratory-scale isolation, modification, and characterization of novel starches from accessible botanical sources and food wastes. When creating a new starch product, one should consider the different physicochemical changes that may occur. These changes include the course of gelatinization, the formation of starch-lipids and starch-protein complexes, and the origin of resistant starch (RS). This paper informs about the properties of individual starches, including their chemical structure, the size and crystallinity of starch granules, their thermal and pasting properties, their swelling power, and their digestibility; in particular, small starch granules showed unique properties. They can be utilized as fat substitutes in frozen desserts or mayonnaises, in custard due to their smooth texture, in non-food applications in biodegradable plastics, or as adsorbents. The low onset temperature of gelatinization (detected by DSC in acorn starch) is associated with the costs of the industrial processes in terms of energy and time. Starch plays a crucial role in the food industry as a thickening agent. Starches obtained from ulluco, winter squash, bean, pumpkin, quinoa, and sweet potato demonstrate a high peak viscosity (PV), while waxy rice and ginger starches have a low PV. The other analytical methods in the paper include laser diffraction, X-ray diffraction, FTIR, Raman, and NMR spectroscopies. Native, "clean-label" starches from new sources could replace chemically modified starches due to their properties being similar to common commercially modified ones. Human populations, especially in developed countries, suffer from obesity and civilization diseases, a reduction in which would be possible with the help of low-digestible starches. Starch with a high RS content was discovered in gelatinized lily (>50%) and unripe plantains (>25%), while cooked lily starch retained low levels of rapidly digestible starch (20%). Starch from gorgon nut processed at high temperatures has a high proportion of slowly digestible starch. Therefore, one can include these types of starches in a nutritious diet. Interesting industrial materials based on non-traditional starches include biodegradable composites, edible films, and nanomaterials.

Physical modification of high amylose starch using electron beam irradiation and heat moisture treatment: The effect on multi-scale structure and in vitro digestibility.

This study explores a new strategy for manipulating the digestibility of high-amylose maize starch (HAMS) through combinative modifications, namely depolymerization via electron beam irradiation (EBI) followed by reorganizing glucan chains via heat moisture treatment (HMT). The results show that semi-crystalline structure, morphological features and thermal properties of HAMS remained similar. However, EBI increased branching degree of the starch at high irradiation dosage (20kGy), resulting in more readily leached amylose during heating. HMT increased the relative crystallinity (3.9-5.4% increase) and V-type fraction (0.6-1.9% increase), without significant changes (p>0.05) in gelatinization onset temperature, peak temperature and enthalpy. Under simulated gastrointestinal conditions, the combination of EBI and HMT either had no effect or negative effect on starch enzymatic resistance, depending on the irradiation dosage. These results suggest that the depolymerization by EBI predominantly affects the changes in enzyme resistance, rather than the growth and perfection of crystallites induced by HMT.

Altering structure and enzymatic resistance of high-amylose maize starch by irradiative depolymerization and annealing with palmitic acid as V-type inclusion compound

This study explored a new physical modification approach to regulate enzymatic resistance of high-amylose starch for potentially better nutritional outcomes. High-amylose maize starch (HAMS) was subjected to chain depolymerization by electron beam irradiation (EBI), followed by inducing ordered structure through annealing in palmitic acid solution (APAS). APAS treatment significantly promotes the formation of ordered structure. Starch after the combinative modification showed up to 5.2 % increase in total crystallinity and up to 1.2 % increase in V-type fraction. The EBI-APAS modification led to increased gelatinization temperature (from 66.1 to 87.6 °C) and reduced final digested percentage under in vitro stimulated digestion conditions. The moderate extent of depolymerization resulted in higher enzymatic resistance, indicating that the extent of depolymerization is crucial in EBI-APAS modification. Pearson analysis showed a significant correlation between gelatinization onset temperature and digestion kinetic parameter (k1, rate constant of fast-phase digestion). Overall, the result suggests that ordered structures of degraded molecules induced by the combinative modification contribute to the enzymatic resistance of starch. This study sheds lights on future applications of EBI-APAS approach to regulate multi-scale structures and nutritional values of high-amylose starch.

Physicochemical, thermal, pasting, morphological, functional and bioactive binding characteristics of starches of different oat varieties of North-Western Himalayas

Starches were isolated from five oat varieties (SFO-1, SFO-3, Sabzar, SKO-20 and SKO-96) grown in North-Western Himalayas of India. Moisture content of the varieties ranged from 9.25 ± 0.09 to 13.21 ± 0.11 %, indicating their shelf-stability. Results suggested >90 % purity of starches as was evident from values of ash, proteins, and lipids. Amylose content results showed that all starches fall within category of intermediate-amylose starches. Lambdamax, blue value and OD620/550 were found significantly (p ≤ 0.05) higher in SKO-20. Sabzar exhibited higher starch hydrolysis percentage of 85.16 % whereas, lowest was observed in SKO-20 (78.12 %). Degree of syneresis was higher in SKO-20 however, its freeze-thaw stability was lesser. Wide peak in FTIR spectra at 3320 cm−1 confirms nature of starches. SKO-20 exhibited significantly higher onset gelatinization temperature (65.19 ± 1.06 °C) and enthalpy (15.78 ± 0.15 J/g) whereas, Sabzar exhibited lowest enthalpy. Pasting characteristics indicated lowest and highest final viscosity in SKO-20 (341.30 ± 2.11 mPas) and SKO-96 (1470 ± 4.56 mPas), respectively. SEM results indicated irregular and polygonal shape of starches with size <10 μm. SKO-20 exhibited lowest disintegration time of 2.08 ± 0.01 min and Sabzar showed highest (3.31 ± 0.07 min). SKO-20 released more curcumin (71.28 %) whereas, Sabzar released less. This suggests that SKO-20 could be used as better excipient for delivery of curcumin at target site.

Effects of genotype and environment on productivity and quality in Californian malting barley

AbstractMalting barley (Hordeum vulgare L.) productivity and grain quality are of critical importance to the malting and brewing industry. In this study, we analyzed 12 malting barley genotypes across 8 locations in California and 3 years (2017–2018, 2018–2019, and 2020–2021). The effects of genotype (G), location (L), year (Y), and their interactions were assessed on grain yield (kg ha−1), grain protein content (%), individual‐grain weight (mg), thousand kernel weight (TKW; g), grain size (plump and thin; %), onset gelatinization temperature (GT; temperature at which starch starts to gelatinize), peak GT, offset GT, difference between onset and peak GT, and difference between peak and offset GT. L, Y, and their interaction explained the largest variance for all traits except TKW, peak GT, and difference between onset and peak GT, for which G explained the largest variance. Yield and plump (%) were weakly negatively correlated with onset and peak GT (Pearson's r of −0.15 to −0.21) but showed a positive correlation with the difference between peak and offset GT (Pearson's r of 0.37 and 0.36). The 2020–2021 samples formed partially distinct clusters in principal component analysis, mainly discriminated by high percentage of thins and high onset GT. These findings illustrate the key roles of G, L, and Y in determining malting barley productivity and quality.

Morphological, structural, chemical, vibrational, thermal, pasting, and functional changes in pea starch during germination process

Background: Changes in the structural and physicochemical properties of pea starch could be significantly affected by germination treatment, which can provide a theoretical basis for promoting the use of this starch in the food industry. Methods: This work aims to evaluate the effect of germination time on the structural, thermal, rheological and functional properties of pea starches to determine their potential in the production of fermented beverages. The physicochemical changes during the germination process of peas and native and germinated starch granules were evaluated. Results: For germination critical time was 0.985 days, with 95% of germinated grains. The starch grains did not undergo any morphological change during the germination process as seen in the scanning electron microscopy images, indicating the absence of the α and ß - amylases responsible for the starch splitting. The X-ray patterns revealed that the crystalline structures of pea starch with and without germination were unchanged and contained by hexagonal and orthorhombic glucopyranose crystals. The viscosity profiles of the starches do not show significant changes; the most representative change is the increase in the gelatinization onset temperature of the paste from germinated starches compared to native starch. The functional properties of starches showed generally low values, with statistically significant differences between water absorption index, water solubility index, and starch swelling power and germination time. Conclusions: In general terms, it can be concluded that lentil starch does not undergo significant changes in its physicochemical and functional integrity with respect to the grain germination process.

Morphological, Functional, and Physico‐Chemical Properties of Non‐Conventional Starch Derived from Discarded Immature Apples

AbstractThe starch yield of 23–28% (db) with 35–43% amylose content is recovered from different immature apple varieties. Scanning electron microscopy reveals the presence of the dome to spherical shaped granules of 3.1–11.62 µm size. The transition temperatures, onset temperature, peak temperature, conclusion temperature, and enthalpy of gelatinization are calculated using differential scanning calorimetry (DSC) ranges between 61.62 and 64.48 °C, between 64.61 and 68.07 °C, between 68.64 and 72.37 °C, and between 4.35 and 17.49 J g−1, respectively. The water absorption capacity and oil absorption capacity of starches range between 1.036 and 1.372 mL g−1 and between 0.876 and 1.125 mL g−1, respectively. The peak viscosity of 638–1942 cP is achieved in 3.8–6.10 min at a pasting temperature of 65–71 °C. A yield stress of 10–39 Pa is sufficient to instigate the Herschel Bulkley flow. The paste of Mollie's Delicious starch is more structured and elastic; its gel has a hardness of 3.5 N and maximum recovery strength.

Starch Fine Molecular Structure Is the Driving Factor for Starch Gelatinization Property in Both Wheat Flour and Wheat Dough

AbstractThe thermal properties of dough are critical for eating and processing quality of wheat flour‐based products. Although the gelatinization properties of wheat starch or flour as affected by starch molecular structures have been investigated, it remains largely unexplored how starch structures determine the gelatinization properties of wheat dough. The gelatinization properties of 10 wheat flours and corresponding doughs with distinct starch fine molecular structures are thus investigated. A parabolic relationship is observed between amylose content and gelatinization temperatures of both wheat flour and dough. Amylopectin molecular size is positively correlated while amylose molecular size negatively correlates with gelatinization onset and peak temperatures of wheat flour. Amylose molecular size is negatively correlated with gelatinization temperatures of wheat dough. Possible mechanisms are further discussed. These results provided first associations between starch molecular structures and thermal properties of wheat dough, and their difference compared to those from wheat flour, which can help the food industry select suitable wheat varieties with improved dough quality.

Incorporation of Huangjing flour into cookies improves the physicochemical properties and in vitro starch digestibility

Huangjing contains no starch but rich in health-promoting compounds. The effects of Huangjing flour (HJF) on the physicochemical properties and quality of cookies were investigated by partially replacing wheat flour with HJF. The addition of HJF increased water solubility of the mixed flour and improved the crispness of cookies. The starch was lower approximately 69%, but obtained 8% higher protein and fat content than the control. The resistant starch increased from 23.74 to 41.37 g 100 g−1, which significantly reduced the in vitro digestibility of the cookies and resulted in a much lower estimated glycemic index (eGI) 53.67 (eGI<55) compared with 61.81 wheat flower control when 40% HJF was included. The microstructure of the products indicated that the exposure area of starch particles was greatly reduced by the addition of HJF. The onset temperature of gelatinization increased from 60.75 °C to 61.75 °C, and the enthalpy of gelatinization decreased from 1.68 to 0.88 J g−1 with the presence of 40% HJF, suggesting that the HJF could retard the gelatinization of the cookies. The above results demonstrate that inclusion of HJF into cookies improves the quality of cookies and also provides a strategy for the production of low-GI foods.

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 (To), peak (Tp) 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, To, Tp 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.

Effects of bran pigmentation and parboiling on rheological properties of waxy rice in neutral and acidic environments

AbstractBackground and ObjectivesPigmented rice is a good source of polyphenols that can interact with proteins to affect starch rheological properties. Parboiling influences rice functional properties via starch gelatinization and protein denaturation, but its effects on polyphenol/protein/starch interactions are unknown. This study investigated the rheological properties of pigmented (HB‐1) and nonpigmented (Neches) waxy rice in neutral (water) and acidic (0.1 N HCl) environments as affected by soaking at room temperature or 5°C below onset gelatinization temperature (To) and steaming.FindingsWhole grain rice and starch of both varieties shared similar pasting viscosities, whereas milled HB‐1 displayed a higher peak viscosity than its derived starch. Soaking at 5°C&lt;To increased pasting viscosities of whole grain and milled Neches and whole grain HB‐1, but decreased those of milled HB‐1. Parboiled whole grain and milled HB‐1 after high‐temperature soaking showed lower storage (G’) and loss (G”) modulus in neutral environment, but enhanced viscoelastic properties in acidic environment.ConclusionThe results provide evidence for the presence of inherent polyphenol/protein/starch interactions in pigmented rice. These interactions may be enhanced from protein denaturation during parboiling but disrupted when exposed to acid to increase starch swelling.Significance and NoveltyPolyphenol/protein/starch interactions may help develop functional foods with increased viscosity in acidic environment.