Rapid Visco Analyzer Profile Research Articles

Retraction: Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

Retraction: Responses of Rapid Viscoanalyzer Profile and Other Rice Grain Qualities to Exogenously Applied Plant Growth Regulators under High Day and High Night Temperatures.

Assessment of the Addition of Cricket (Acheta domesticus) Powder to Chickpea (Cicer arietinum) and Flaxseed (Linum usitatissimum) Flours: A Chemometric Evaluation of Their Pasting Properties

Edible insects have been evaluated as an alternative and sustainable source of protein because of their nutritive and functional properties for humans and domestic animals. The objective of this study was to assess the use of chemometric [principal component analysis (PCA) and partial least squares (PLS)] combined with Rapid Visco Analyser (RVA) profiles to evaluate the addition of cricket powder (CKP) to chickpea (CPF) and flaxseed (FxF) flours. The results of this study showed that the addition of CKP powder to both CPF and FxF flours affects the pasting properties of the samples; in particular, a reduction in the peak (PV) and final viscosity (FV) was observed. The use of chemometric data techniques such as PCA and PLS regression allowed for a better interpretation of the RVA profiles. Both PCA and PLS regression allowed to qualitative and quantitatively identify the addition level of CKP powder to CPF and FxF flour samples. Differences in the PLS loadings associated with the RVA profile due to the addition of cricket powder were observed. The development of these methodologies will provide researchers and the food industry with better tools to both improve and monitor the quality of ingredients with functional properties as well as to further understand the use of insects as alternative sources of protein.

Predicting wheat flour quality for making Japanese sponge cake using flour pasting properties as measured by the Rapid Visco Analyzer

AbstractBackground and ObjectivesThe objective of this study was to evaluate a series of Rapid Visco Analyzer (RVA) methods for their ability to produce results that were predictive of Japanese sponge cake (JSC) quality. Two solvents (water and 50% [w/w] sucrose in water) and two temperature profiles [Standard 1 (STD 1) and an internal cake temperature profile] were selected to run across a diverse set of flour samples from two crop years that possessed variable bake performance. The results were analyzed for predictive outcomes for JSC prepared using a mechanical fold method.FindingsThe solvent retention capacity (SRC) results did not show any significant trends with JSC quality. The RVA results from both profiles using water as the solvent did not show a significant correlation with JSC quality while the 50% (w/w) sucrose solvent was significantly correlated (p ≤ .01). The STD 1 and internal cake temperature profile batter pasting viscosity (BPV) using the sucrose solvent showed significant (p ≤ .01) correlations with mechanical folded JSC volume (r = .97), firmness (r = −.88), and overall score (r = .85).ConclusionsThe RVA BPV results showed that a 50% sucrose solvent could more accurately be used to predict and screen for JSC quality outcomes. Both RVA profiles could be used with a sucrose solvent to predict JSC quality. JSC volume and overall score showed significant positive correlations with BPV while firmness had a significant negative correlation.Significance and NoveltyThis research identified two RVA profiles that when paired with a 50% (w/w) sucrose solvent could be used to screen for JSC quality using less flour and taking less time than a bake test. This test could potentially assist breeders and millers in quicky screening flours for efficient decision making. This is the first time an RVA temperature profile that mimics the internal rise in temperature for a JSC during baking has been used to predict JSC quality. In addition, the STD 1 profile using the 50% (w/w) sucrose solvent has not been previously used to predict JSC quality.

Comparative performance of superior and inferior grains for quality parameters following diversified temperature during grain filling stage

The responses of rice quality including milling, appearance, and eating quality between superior (SG) and inferior grains (IG) to temperature during grain filling stage (TGF) remained poorly understood, especially for eating quality. Therefore, the regulation of TGF (17.6−30.4 °C) on quality of three indica hybrid varieties (IHs) was investigated by setting multiple sowing dates and the mechanism underlying taste difference was explored by monitoring chemical compositions, rapid visco analyser (RVA) profiles, and texture properties. Results suggested that TGF ranging from 23.3 to 25.2 °C could comprehensively improve the milling, appearance and eating quality of IHs, and the optimal TGF of SG was 2.3–4.2 °C lower than that of IG. Compared with chemical compositions and RVA profiles, texture properties were better for evaluating the eating quality of IHs. When TGF was higher than 24.0 °C, the taste value of IG was higher than that of SG mainly due to higher elasticity. The findings indicate that TGF had differential regulatory effects on SG and IG, which could provide a useful reference for cultivation of high-quality rice varieties under global climate change. Besides, the determination of texture properties was a reliable method for taste evaluating of IHs in the breeding process.

Starch Properties and Morphology of Eight Floury Endosperm Mutants in Rice.

Besides increasing grain yield, improving rice (Oryza sativa L.) quality has been paid more and more attention recently. Cooking and eating quality (CEQ) is an important indicator of rice quality. Since CEQs are quantitative traits and challenging for measurement, efforts have mainly focused on two major genes, Wx and SSIIa. Chalkiness and floury endosperm significantly affect the eating quality of rice, leading to noticeable changes in CEQ. Due to the easily observable phenotype of floury endosperm, cloning single gene mutations that cause floury endosperm and evaluating changes in CEQs indirectly facilitate the exploration of the minor genes controlling CEQ. In this study, eight mutants with different degrees of floury endosperm, generated through ethylmethane sulfonate (EMS) mutagenesis, were analyzed. These mutants exhibited wide variation in starch morphology and CEQs. Particularly, the z2 mutant showed spherical starch granules significantly increased rapid visco analyzer (RVA) indexes and urea swelling, while the z4 mutant displayed extremely sharp starch granules and significantly decreased RVA indexes and urea swelling compared to the wild type. Additionally, these mutants still maintained correlations with certain RVA profiles, suggesting that the genes PUL, which affect these indexes, may not undergo mutation. Cloning these mutated genes in the future, especially in z2 and z4, will enhance the genetic network of rice eating quality and hold significant importance for molecular marker-assisted breeding to improve rice quality.

A combined extrusion, retrogradation, and cross-linking strategy for preparing starch-based straws with desirable mechanical properties

This work developed a novel strategy for producing starch straws with desirable mechanical properties by a combination of extrusion, retrogradation, and sodium trimetaphosphate (STMP) cross-linking. The straws were prepared by first extruding starch, glycerin, and water (10:1:1) with a double screw extruder, then retrograding the resulting straws at 4 °C for 6 h, and finally cross-linking the straws. Rapid visco-analyzer profiles showed decreases in the viscosity of milled straws with increases in the cross-linking duration, perhaps reflecting a higher degree of crosslinking. Fourier transform infrared spectroscopy showed evidence of more hydrogen bonds in the straws with a longer cross-linking duration, while thermogravimetric analysis indicated higher thermal stability for the cross-linked straws than for the controls. The straw cross-linked for 3 h showed 1.52 times higher stiffness after soaking in room-temperature water for 30 min (4967.56 g/s), and 1.88 times higher stiffness after soaking in 60 °C hot water for 5 min (5371.89 g/s) than the original straw. STMP cross-linking also improved the starch straw mechanical properties after soaking in common soft drinks. These findings identify a potential new way to produce biodegradable straws with desirable properties from starch, an affordable biomaterial, while also addressing the problem of petroleum-based plastic pollution.

Effect of Integrated Organic–Inorganic Amendments on Leaf Physiological and Grain Starch Viscosity (Rapid Visco-Analyzer Profile) Characteristics of Rice and Ultisols Soil Quality

Current farming systems are highly reliant on chemical fertilizers (CF), which negatively affect soil health, the environment, and crop productivity. Substituting organic fertilizer for chemical fertilizer (CF) is an important agricultural practice that improves soil health and crop productivity and is eco-friendly. To explore the effects of organic fertilizer in the form of cattle manure (CM) or poultry manure (PM) combined with CF on soil properties, leaf physiological traits, and grain physiochemical characteristics of rice, a 2-year field experiment was conducted in a dual cropping system with six treatments: Neg-CF (no N fertilizer control), Pos-CF (100% CF), High-CM (60% CM + 40% CF), Low-CM (30% CM + 70% CF), High-PM (60% PM + 40% CF), and Low-PM (30% PM + 70% CF). The results exhibited that the adding of organic manure significantly improved soil chemical traits such as soil organic C (SOC), total N (TN), and available N (AN). Similarly, applying the combined fertilizer led to significant increases in the leaf net photosynthetic rate (Pn), SPAD values, and rice grain nutritional and cooking characteristics according to Rapid Visco-Analyzer (RVA) profile. Average increases in SOC, TN, Pn, starch content (SC), and amylose content (AC) were 16%, 12%, 9%, 7%, 9%, and 12%, respectively, across the year in the Low-PM compared to the Pos-CF treatment. Moreover, the manure amendments significantly altered the RVA profile attributes, including peak viscosity, tough viscosity, final viscosity, and the setback and pasting temperatures compared to Pos-CF. Linear regression analysis revealed that SOC and TN were positively associated with leaf Pn and SPAD values. Further, leaf Pn and SPAD were positively correlated with rice grain SC and AC. The correlation heat map analyses revealed a positive correlation in the RVA profile between the soil properties and leaf physiological traits. These correlation analyses showed that the increase in soil chemical traits and leaf physiological activities played a significant role in higher rice grain nutritional and cooking quality. Overall, the findings of this study show that the integrated use of organic fertilizers and CF in rice fields enhances soil functionality and the quality of rice on a sustainable basis.

Effects of Biochar Amendment and Nitrogen Fertilizer on RVA Profile and Rice Grain Quality Attributes.

Improving rice production in modern agriculture relies heavily on the overuse of chemical fertilizer, which adversely affects grain quality. Biochar (BC) application is well known for enhancing rice yield under reduced nitrogen (N) application. Therefore, we conducted a two-year field experiment in 2019 and 2020 to evaluate RVA profile characteristics, grain milling, and appearance qualities under four BC rates (0, 10, 20, 30 t ha−1) in combination with two N levels (135 and 180 kg ha−1). The results showed that BC at 30 t ha−1 along with 135 kg N ha−1 improved rapid visco-analyzer (RVA) profile attributes, including peak viscosity (4081.3), trough viscosity (3168.0), break down (913.3), final viscosity (5135.7), and set back (1967.7). Grain yield, grain rain length, milled rice rate, percent grains with chalkiness, amylose, and starch content were improved by 27%, 23%, 37%, 24%, 14%, and 8%, respectively, in the plots treated with the combination of 30 t BC ha−1 and 180 kg N ha−1. A positive coefficient of correlation was observed in RVA profile, milling, and apparent quality of rice with soil properties. These results suggested that BC at 20 to 30 t ha−1 in combination with 135 kg N ha−1 is a promising option for enhancing grain yield, RVA profile, appearance, and milling quality.

Simultaneous Improvement of Grain Yield and Quality through Manipulating Two Type C G Protein Gamma Subunits in Rice.

Heterotrimeric G protein signaling is an evolutionarily conserved mechanism in diverse organisms that mediates intracellular responses to external stimuli. In rice, the G proteins are involved in the regulation of multiple important agronomic traits. In this paper, we present our finding that two type C G protein gamma subunits, DEP1 and GS3, antagonistically regulated grain yield and grain quality. The DEP1 gene editing we conducted, significantly increased the grain number per panicle but had a negative impact on taste value, texture properties, and chalkiness-related traits. The GS3 gene editing decreased grain number per panicle but significantly increased grain length. In addition, the GS3 gene-edited plants showed improved taste value, appearance, texture properties, and Rapid Visco Analyser (RVA) profiles. To combine the advantages of both gs3 and dep1, we conducted a molecular design breeding at the GS3 locus of a “super rice” variety, SN265, which has a truncated dep1 allele with erect panicle architecture, high-yield performance, and which is of mediocre eating quality. The elongated grain size of the sn265/gs3 gene-edited plants further increased the grain yield. More importantly, the texture properties and RVA profiles were significantly improved, and the taste quality was enhanced. Beyond showcasing the combined function of dep1 and gs3, this paper presents a strategy for the simultaneous improvement of rice grain yield and quality through manipulating two type C G protein gamma subunits in rice.

QTL mapping for starch paste viscosity of rice (Oryza sativa L.) using chromosome segment substitution lines derived from two sequenced cultivars with the same Wx allele

BackgroundThe eating and cooking qualities (ECQs) of rice (Oryza sativa L.) are key characteristics affecting variety adoption and market value. Starch viscosity profiles tested by a rapid visco analyzer (RVA) offer a direct measure of ECQs and represent the changes in viscosity associated with starch gelatinization. RVA profiles of rice are controlled by a complex genetic system and are also affected by the environment. Although Waxy (Wx) is the major gene controlling amylose content (AC) and ECQs, there are still other unknown genetic factors that affect ECQs.ResultsQuantitative trait loci (QTLs) for starch paste viscosity in rice were analyzed using chromosome segment substitution lines (CSSLs) developed from the two cultivars 9311 and Nipponbare, which have same Wx-b allele. Thus, the effect of the major locus Wx was eliminated and the other locus associated with the RVA profile could be identified. QTLs for seven parameters of the starch RVA profile were tested over four years in Nanjing, China. A total of 310 QTLs were identified (from 1 to 55 QTLs per trait) and 136 QTLs were identified in more than one year. Among them, 6 QTLs were stalely detected in four years and 26 QTLs were detected in at least three years including 13 pleiotropic loci, controlling 2 to 6 RVA properties simultaneously. These stable QTL hotspots were co-located with several known starch synthesis-related genes (SSRGs). Sequence alignments showed that nucleotide and amino acid sequences of most SSRGs were different between the two parents. Finally, we detected stable QTLs associated with multiple starch viscosity traits near Wx itself, supporting the notion that additional QTLs near Wx control multiple characteristic values of starch viscosity.ConclusionsBy eliminating the contribution from the major locus Wx, multiple QTLs associated with the RVA profile of rice were identified, several of which were stably detected over four years. The complexity of the genetic basis of rice starch viscosity traits might be due to their pleiotropic effects and the multiple QTL hot spots. Minor QTLs controlling starch viscosity traits were identified by using the chromosome segment substitution strategy. Allele polymorphism might be the reason that QTLs controlling RVA profile characteristics were detected in some known SSRG regions.

Correlation Studies of Starch Pasting Properties Determined Through Rapid Visco Analyzer

In present study, pasting properties of wheat varieties were investigated through rapid visco analyzer (RVA). Starch content was determined by Megazyme kit method varied from 68.88 to 72.73%. Pasting properties indicated variability from 65.25 to 67.80 °C (pasting temperature), 3.22 to 6.00 min (peak time), 1330 to 1784 cP (peak viscosity), 645 to 1002 cP (trough viscosity), 1799 to 2565 cP (final viscosity) 685 to 782 cP (breakdown viscosity) and 1154 to 1563 (setback viscosity). Starch content and seven parameters observed from RVA profiles of various wheat varieties were evaluated for their inter- dependence. Starch content indicated a significantly positive association with trough viscosity (r = 0.926*) and final viscosity (r = 0.917*). Present data show that peak viscosity had significant and positive relationship with setback (r = 0.879*) and trough viscosity (r = 0.976**).
 Novelty statement. Pasting properties determine end use quality of wheat flour and primarily relates to starch content of wheat flour, which is present in largest proportion. In Pakistan, various wheat cultivars are grown in different climate. As a result, the variations in physico-chemical as well as rheological properties of wheat varieties is anticipated. Significant correlations found out in present study are valuable for the evaluation of effect of pasting properties alone and their interaction.

Meta-Analysis of Qtl Associated With Starch Pasting Viscosity in Rice (Oryza Sativa L.)

Rapid Visco Analyzer (RVA) profiles are important traits for indicating rice quality, which are controlled by quantitative trait loci (QTL). In the past two decades, hundreds of QTL for rice RVA profiles have been detected, but without an integration study. Consistent QTL regions associated with rice RVA profiles by QTL meta-analysis with genetic information of 592 QTL for eight RVA profiles were studied. A total of 82 meta-QTL for RVA profiles were detected on 12 chromosomes. MQTL possessed narrower confidence intervals than the initial QTL and candidate genes were identified within each MQTL. These MQTL and candidate genes are beneficial for future marker-assisted selection gene cloning.
 Bangladesh J. Bot. 50(2): 269-276, 2021 (June)

Improving rice eating and cooking quality by coordinated expression of the major starch synthesis-related genes, SSII and Wx, in endosperm.

Coordinated regulation of amylose and amylopectin synthesis via manipulation of SSII-2, SSII-3 and Wx expression in endosperm can improve rice eating and cooking quality. With increasing rice consumption worldwide, many researchers are working to increase the yield and improve grain quality, especially eating and cooking quality (ECQ). The rice ECQ is mainly controlled by the expression of starch synthesis-related genes (SSRGs) in endosperm. Although the Wx and SSII-3/SSIIa/ALK genes, two major SSRGs, have been manipulated to improve rice ECQ via various breeding approaches, new methods to further improve ECQ are desired. In our previous study, we enhanced rice ECQ by knocking down SSII-2 expression in the japonica Nipponbare cultivar (carrying the Wxb allele) via RNA interference. Herein, the SSII-2 RNAi was introduced into two Nipponbare-derived near-isogenic lines (NILs), Nip(Wxa) and Nip(wx), carrying Wxa and wx alleles respond for high and no amylose levels, respectively. Analysis of physicochemical properties revealed that the improved grain quality of SSII-2 RNAi transgenic lines was achieved by coordinated downregulating the expression of SSII-2, SSII-3 and Wx. To further confirm this conclusion, we generated ssii-2, ssii-3 and ssii-2ssii-3 mutants via CRISPR/Cas9 technique. The amylopectin structure of the resulting ssii-2sii-3 mutants was similar to that in SSII-2 RNAi transgenic lines, and the absence of SSII-2 decreased the amylose content, gelatinisation temperature and rapid visco-analyser profile, indicating essential roles for SSII-2 in the regulation of amylopectin biosynthesis and amylose content in rice endosperm. The effect of SSII-2 was seen only when the activity of SSII-3 was very low or lacking. Our study provides novel approaches and valuable germplasm resources for improving ECQ via plant breeding.

Correlation of taste values with chemical compositions and Rapid Visco Analyser profiles of 36 indica rice (Oryza sativa L.) varieties

Yield, taste quality, and cultivar utilisation improvements are important research topics in indica rice breeding. Herein, we compared the relative effectiveness and relationship of three taste evaluation methods, namely, chemical composition, Rapid Visco Analyser (RVA), and taste analyser. We assessed associations among these methods using 36 indica varieties commonly grown in Yunnan, Sichuan, and Guizhou, China. Temperature and sunlight duration during grain filling influenced rice cooking quality. Varieties with high taste quality had low amylose and protein contents; high peak viscosities and breakdowns; and low hold viscosities, setbacks, and final viscosities. Protein and combined protein and amylose explained 38.6% and 62.1% of the variation in taste value, respectively. The RVA profile was affected by protein, amylose, and amylopectin contents and explained 60.5% of the taste-value variation. This study lays the foundation for taste evaluation of high-quality rice varieties early in the breeding process, which can improve cultivation and marketing potential.

Assisted selection of eating quality progeny of indica (O. sativa L. ssp. indica) and japonica (O. sativa L. ssp. japonica) hybrids using rice starch properties

Eating quality (EQ) of rice is mainly determined by sensory evaluation using tasting, which is affected by the taster’s geographic residential area, gender, and age. The sensory evaluation protocol also requires rice samples (usually > 500 g) larger than the amount harvested from the early generations of breeding in many cases, thereby hindering the sensory tasting practices. The characteristics of rice starch have a significant impact on EQ; however, information on starch assisted-selection of EQ is insufficient. In this study, the recombinant inbred lines and backcross recombinant inbred lines constructed by the hybridization of japonica (O. sativa L. ssp. japonica) rice (cv. Toyonishiki) and indica (O. sativa L. ssp. indica) rice (cv. Qishanzhan) were used as test materials to analyze and explore the relationships between the amylose content (AC), rapid visco analyzer (RVA) profile characteristics, and the EQ score obtained from sensory tasting assessment. We provided a feasible solution to use rice starch properties to assist in selection of EQ. The results indicated that AC and RVA profile characteristics including trough viscosity (TV), final viscosity (FV), breakdown (BD), and setback (SB) were closely related to the EQ values. Furthermore, an integrated indicator—i.e., starch properties quality (SPQ)—that represented a more comprehensive characterization of rice starch, was derived based on the EQ evaluation hierarchy and weighted AC, TV, FV, BD, and SB values. The correlation between SPQ and EQ was significant (p < 0.001), and was significantly higher compared with using individual indicators. Moreover, the SPQ method requires less rice samples (i.e., 3 g of milled rice flour) and can be applied to assisted-selection for EQ in early generations of breeding. This study provid esessential technical support for the rapid and accurate identification of the EQ of progeny of indica–japonica hybrids.

The effect of pre and post-ultrasonication on the aggregation structure and physicochemical characteristics of tapioca starch containing sucrose, isomalt and maltodextrin

The present research investigated the aggregation behaviors of different levels (4, 8 and 12%) of incorporation of sucrose, isomalt and maltodextrin to pre or post- ultrasonication (400 W, 10 min at 60 °C) by fourier transform infrared spectroscopy (FTIR), microstructure by scanning electron microscopy (SEM), water absorption, pasting by rapid visco analysis (RVA), and thermal by differential scanning calorimetry (DSC). FTIR results showed that the aggregation process between polyol and starch after ultrasonication is more effective than before ultrasonication owning to more hydroxyl groups of polyols are engaged with the hydrogen bonds of starch which is more pronounced peaks at 1500–1750 cm−1, 1700–2700 cm−1 and 3000–3700 cm−1. These findings are in line with the results from SEM analysis. The spots, deformations and cross-linking created by the polyols were more significant after ultrasound assisted pregelatinizion. Impact intensity of polyol on starch granule was reduced in the following order: isomalt > sucrose > maltodextrin. RVA profiles showed that through the incorporation of polyols after sonication, were higher in samples pregelatinized in comparison with those before sonication.

Mapping quantitative trait loci associated with starch paste viscosity attributes by using double haploid populations of rice (Oryza sativa L.)

The paste viscosity attributes of starch, measured by rapid visco analyzer (RVA), are important factors for the evaluation of the cooking and eating qualities of rice in breeding programs. To determine the genetic roots of the paste viscosity attributes of rice grains, quantitative trait loci (QTLs) associated with the paste viscosity attributes were mapped, using a double haploid (DH) population derived from Zhongjiazao 17 (YK17), a super rice variety, crossed with D50, a tropic japonica variety. Fifty-four QTLs, for seven parameters of the RVA profiles, were identified in three planting seasons. The 54 QTLs were located on all of the 12 chromosomes, with a single QTL explaining 5.99 to 47.11% of phenotypic variation. From the QTLs identified, four were repeatedly detected under three environmental conditions and the other four QTLs were repeated under two environments. Most of the QTLs detected for peak viscosity (PKV), trough viscosity (TV), cool paste viscosity (CPV), breakdown viscosity (BDV), setback viscosity (SBV), and peak time (PeT) were located in the interval of RM6775–RM3805 under all three environmental conditions, with the exception of pasting temperature (PaT). For digenic interactions, eight QTLs with six traits were identified for additive×environment interactions in all three planting environments. The epistatic interactions were estimated only for PKV, SBV and PaT. The present study will facilitate further understanding of the genetic architecture of eating and cooking quality (ECQ) in the rice quality improvement program.

Diversity analysis of starch physicochemical properties in 95 proso millet (Panicum miliaceum L.) accessions

In this study, 95 accessions of proso millet (Panicum miliaceum L.) were characterized for starch physicochemical properties, including apparent amylose content (AAC), gel textural properties, Rapid Visco Analyzer (RVA) pasting viscosity properties, thermal and retrogradation properties. Based on genotypic data, the genetic diversity and inter-relationship of these starch traits were analyzed. Diverse starch quality was found, for example, AAC ranged from 0 to 32.3%, gelatinization temperature (GT) varied from 71.5 to 79.0 ℃, and RVA profile showed distinct patterns among proso millet of different AAC types. Interestingly, high AAC proso millet usually had GT lower than that of low AAC proso millet, which is different from the findings in rice starch. Many starch traits were significantly correlated and most of the 18 tested traits could be classified as either AAC-related traits or GT-related traits. In summary, the information presented here will be useful for further development of proso millet products.

Amylose content and RVA profile characteristics of noodle rice under different conditions

AbstractFew studies have been conducted on changes in the amylose content and rapid visco‐analyzer (RVA) profile characteristics of noodle rice cultivars under different ecological conditions. This research was conducted in 2017 and 2018 to evaluate changes in amylose content and RVA profile characteristics of ten noodle rice cultivars at three test sites. The cultivars were planted in Nanning, Hengyang, and Nanchang in 2017. Four cultivars were planted at each site on seven sowing dates with an interval of 15 d in 2018. Grain amylose content and RVA profile characteristics were determined after the rice had been stored for three months. The results showed that there were significant differences between the cultivars in the amylose content and RVA profile characteristics. The RVA profile characteristics of the 10 rice cultivars did not exhibit a similar trend for the three test sites. The average coefficient of variation was 8.6% for the amylose content, greater than 25% for the breakdown (BD) and setback (SB); 10 to 20% for the consistency (CSV) and peak viscosity (PV); and less than 10% for the trough viscosity (TV), final viscosity (FV), peak time (PT), and pasting temperature (PaT). The correlation analysis showed that the amylose content was significantly correlated with the PT, TV, BD, PaT, SB, and FV. It was concluded that there were significant differences in the amylose content and RVA profile characteristics between the rice cultivars and significant genetic‐environment interaction effects. The amylose content of the special noodle rice cultivars was significantly correlated with the RVA profile characteristics.

Rheology of The Glutinous Rice Flour, Coconut Milk, and Palm Sugar Mixed System in A Traditional Food Dodol Ulame

Triple mixed of glutinous rice flour, coconut milk, and palm sugar paste with ratio of 1.0:2.5:0.5, 1.0:2.0:1.0, 1.0:1.5:1.5, 1.0:1.0:2.0, 1.0:0.5:2.5 were studied using rapid visco-analyzer (RVA), rheometer, and polarized light microscope to investigate its pasting properties, flow behavior index, dynamic rheology, and microstructure respectively. The power-law and Herschel-Bulkley models were used to evaluate its steady rheological properties. The RVA profile shows low viscosity profile and low breakdown viscosity for all ratio of dodol ulame paste. The lowest breakdown viscosity occurred at the ratio of 1.0:2.5:0. Meanwhile, the highest setback viscosity occurs at the ratio of 1.0:0.5:2.5. Indicating the highest riqidity due to high sugar content. The apparent viscosity decreased with increasing shear rate for all triple mixed exhibited a typical shear-thinning behaviour (n&lt;1) of the system. Increasing the proportion of coconut milk decreased the consistency coefficient, k, and increased the flow behaviour index, n of the system. The dynamic rheology resulted in the higher G” value over the entire frequency. Maltese crosses disappeared at 90 °C for the ratio of system 1.0:0.5:2.5 and 1.0:1.0:2.0 and 80 °C for the ratio of system 1.0:1.0:2.0, 1.0:1.5:1.5 and 1.0:1.0:2.0. The study suggests that coconut milk and palm sugar had an important role on the rheology of dodol ulame paste, consequently it affects the gelatinization, viscosity, and gel-like behaviour of the glutinous rice flour, coconut milk, and palm sugar mixed system. Further study on the preference and nano structure is undertaken to reveal its possibility to produce better quality dodol ulame.