Rapid Visco Analyzer Profile Research Articles

Influence of drying temperature on the structural and cooking quality properties of black rice

Background and objectivesPaddy rice was dried in a fixed‐bed dryer at 20, 40, 60, 80, and 100°C, with air speed set at 0.5 m/s. The drying kinetics, moisture diffusivity, and morphologic characteristics of black rice grains from IAC 600 genotype were determined.FindingsBlack rice grains dried at 60, 80, and 100°C exhibited a reduction in the head rice percentage after dehusking (HRD) as the temperature increased. This behavior was confirmed by the occurrence of cracks in the endosperm of black rice when observed using an SEM. There was a reduction in cooking time, hardness, adhesiveness, and in the extractability of water‐soluble proteins as well as in the extractability of proteins in 2% sodium dodecyl sulfate media in black rice subjected to 100°C of drying temperature, as compared to 20°C. Conversely, increases in the rehydration ratio of grains dried at 100°C were observed. Increases in the peak and breakdown viscosities and reductions in pasting temperature, final viscosity, and setback viscosity in Rapid Visco Analyzer profile of 100°C‐dried black rice were also observed.ConclusionsThe increase in drying temperature promoted the increase in drying rate (k) and Deff. When black rice grains were dried at 60, 80, and 100°C, there was a decrease in HRD because of the evident increase in the intensity of endosperm fissures. The fissure formation is attributed to drying at temperatures of 60, 80, and 100°C occurring above the glass transition temperature (rubbery region) coupled with a non‐efficient tempering. At 100°C, modifications were observed in the flour pasting properties, indicating the higher extent of protein–starch interactions, confirmed by the reduction of protein extractability.Significance and noveltyFew reports exist on black rice structure and cooking quality as a function of post‐harvest conditions. The present work provides scientific support on how drying temperature impacts black rice quality.

Effects of Wx and Its Interaction With SSIII-2 on Rice Eating and Cooking Qualities.

The Wx gene encodes a granule-bound starch synthase (GBSS) and plays a key role in determining rice eating and cooking qualities (ECQs). SSIII-2 (SSIIIa), a member of the soluble starch synthases, is responsible for the synthesis of long chains of amylopectin. To investigate the effects of Wx and its interaction with SSIII-2 on grain ECQs, a population from a hybrid combination was established as a research material. The genotypes of SSIII-2 and the single nucleotide polymorphisms (SNPs) on intron1, exon6, and exon10 of Wx, and the physicochemical indicators and rapid visco analyzer (RVA) profile characteristics were analyzed. The results revealed various effects of SSIII-2 on rice quality under different backgrounds of Wx alleles. There was no obvious difference between different SSIII-2 alleles under the same background of Wxa, whereas there was a significant diversity under the same background of Wxb. Wxa had a dominant epistasis to SSIII-2 because the effect of SSIII-2 was masked by the massive synthesis of GBSS under Wxa. The apparent amylose content (AAC) was mainly controlled by the In1G/T SNP, and rice gel consistency (GC) was regulated by the Ex10C/T SNP. The combined effects of three SNPs had a significant influence on all ECQs and RVA profile parameters, except for gelatinization temperature. In1T-Ex6A-Ex10C and In1T-Ex6A-Ex10T were classified as being low AAC type. TT-AA-CC and TT-AA-TT had a low AAC and a soft GC. The combined effects of different SNPs of Wx are very important for rice quality breeding.

Using RVA-full pattern fitting to develop rice viscosity fingerprints and improve type classification

The rapid visco analyser (RVA) method has been widely used to investigate starch viscosity and to quality control starch based cereals. Different rice types vary significantly in composition, which is reflected by their different pasting properties. However, the RVA has a reduced sensitivity when it is used to identify types. This study combined RVA profiles with multivariate data analysis methods to obtain more information from the RVA profiles. A total of 152 rice profiles were collected and analyzed by principal component analysis (PCA) and partial least squares-discriminate analysis (PLSDA). The results showed that there were two rice subspecies group types that could be distinguished. In order to optimize the established model, all the data were subjected to a regression analysis and the initial stage was identified as the point when viscosity differences between the groups had the highest regression coefficients. The discrimination accuracy improved when the extracted viscosity data was used. For further verify the applicability of the models, 60 of unknown samples were examined, and the classification accuracy was 100%. All the findings confirmed that this study offers a practical and reliable way to predict rice types, providing a foundation for further studies on origin discrimination and age prediction.

Rice Grain Freshness Measurement Using Rapid Visco Analyzer and Chemometrics

This research developed a rapid and accurate method based on the use of rapid visco analyzer (RVA) for predicting the storage time of rice grain. Freshly harvested rice samples, five waxy and five non-waxy rice grains, were stored in paddy form at ambient room temperature (28–32 °C) for 1 year. During storage, the RVA profiles of the rice samples were recorded every month. In addition, physicochemical properties, such as alkali spreading value (ASV), amylose content, gel consistency, stickiness, and hardness, were measured. Chemometric models including partial least squares (PLS) regression and supervised self-organizing map (supervised SOM) were employed for predicting the storage time based on the use of the RVA profiles, the physicochemical parameters, and both of the datasets simultaneously. In most cases, PLS outperformed supervised SOM. The PLS models established using the RVA profiles provided the best predictive results with root mean square error of cross validation (RMSECV) = 1.2, cross-validated explained variance (Q 2) = 0.90, and the ratio of prediction to deviation (RPD) = 3.2. Based on partial least squares-variable influence on projection (PLS-VIP), pasting properties, including peak viscosity (PV) and final viscosity (FV), were identified as the parameters having strong influence on the prediction models. The developed method detecting the rheological change of the stored rice samples was simple and could be performed quickly with no additional chemicals required.

Mapping quantitative trait loci associated with starch paste viscosity in rice (Oryza sativa L.) under different environmental conditions

AbstractA recombinant inbred line (RIL) population consisting of 153 lines derived from a cross between indica ‘Zhongyouzao8’ and japonica ‘Toyonishiki’ rice was used to detect stable quantitative trait loci (QTL) for rapid visco analyser (RVA) characteristics under four environmental conditions. We identified 93 QTL for RVA profiles, and four pleiotropic regions harbouring stably expressed QTL were detected on chromosomes 2, 6, 7 and 11. These newly identified and stable QTL will facilitate further research into the genetic mechanism regulating RVA profiles. Amylose content (AC) was correlated with RVA traits. AC and RVA traits were unaffected by indica–japonica subspecies differentiation, suggesting that RVA profiles were mainly influenced by the Wx gene. The RIL population was divided into two subpopulations according to Wx genotypes. A total of 106 QTL associated with RVA profiles were detected in the subpopulations. These QTL differed from those detected in the whole population in terms of their genomic location, number, logarithm of odds values and amount of phenotypic variance explained. Using this strategy, we detected QTL with minor effects and eliminated false due to the Wx gene.

Effect of the phytate and hydrogen peroxide chemical modifications on the physicochemical and functional properties of wheat starch

To investigate the characteristics of chemically modified wheat starch, such as oxidized (OWS), cross-linked (CLWS) and dual-modified wheat starches, cross-linked oxidized (COWS) and oxidized cross-linked (OCWS) wheat starches were obtained by 12% hydrogen peroxide (H2O2) and 2% sodium phytate treatments, respectively. After modifications of wheat starch by cross-linking and oxidization, it was determined that native wheat starch was effectively modified with respect to the structure and physicochemical characteristics, as detected by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), Rapid Visco Analyzer (RVA), scanning electron microscopy (SEM) and X-ray diffraction (XRD). DSC analysis demonstrated that peak temperature (Tp) 64.41°C of the COWS was the highest. The RVA viscosity indexes of CLWS were noticeably increased compared with the other four starches, of which three oxidized starch samples showed lower RVA profiles because of oxidation. The XRD result indicated that cross-linked phosphates from sodium phytate were primarily located in the amorphous regions of starch granules. After modifications by different treatments, the starch samples exhibited different morphological characteristics, including A-type and B-type wheat starch granules, which showed much closer contact with each other by the cross-linking reaction under SEM observations. The functional characteristics, including solubility, swelling power, light transmittance and freeze-thaw stability (FTS), of all five treated and untreated wheat starches demonstrated that COWS had the highest solubility at 0.57 and that CLWS showed the best swelling power at 12.63 (g/g). The paste clarity of COWS was improved to 47.72% higher than that of native starch (7.54%), and the water loss of COWS (21.62%) was the lowest, which is beneficial to the production of quick-frozen food. Our results showed that dual-modified starch by using sodium phytate and hydrogen peroxide had significantly altered structural and functional properties. The present study provides fundamental information of dual-modified wheat starch for its potential industrial application.

Effect of interactions between starch and chitosan on waxy maize starch physicochemical and digestion properties

ABSTRACTPhysicochemical and digestion properties of chitosan modified starch prepared by dry heat treatment were investigated. Starch granule aggregation occurred following the addition of chitosan and this trend was enhanced with increasing chitosan concentration. The size of chitosan modified starch particles was about six times of that of the native starch granules. Interactions between the hydroxyl groups of starch and the amino groups of chitosan was confirmed by Fourier transform infrared spectroscopy analysis. The disappearance of the trough in the Rapid Visco Analyzer profile indicated that the cross-links increased the starch shear resistance. The cross-links between starch and chitosan also reduced starch digestion rate compared to the control (p < 0.001), and this reduction was further enhanced with an increasing chitosan concentration. Additionally, the addition of chitosan altered starch digestion kinetics from one phase to two phases, implying that chitosan modification changed both starch structure and its digestion behaviors.

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

High-temperature stress degrades the grain quality of rice; nevertheless, the exogenous application of plant growth regulators (PGRs) might alleviate the negative effects of high temperatures. In the present study, we investigated the responses of rice grain quality to exogenously applied PGRs under high day temperatures (HDT) and high night temperatures (HNT) under controlled conditions. Four different combinations of ascorbic acid (Vc), alpha-tocopherol (Ve), brassinosteroids (Br), methyl jasmonates (MeJA) and triazoles (Tr) were exogenously applied to two rice cultivars (IR-64 and Huanghuazhan) prior to the high-temperature treatment. A Nothing applied Control (NAC) was included for comparison. The results demonstrated that high-temperature stress was detrimental for grain appearance and milling qualities and that both HDT and HNT reduced the grain length, grain width, grain area, head rice percentage and milled rice percentage but increased the chalkiness percentage and percent area of endosperm chalkiness in both cultivars compared with ambient temperature (AT). Significantly higher grain breakdown, set back, consistence viscosity and gelatinization temperature, and significantly lower peak, trough and final viscosities were observed under high-temperature stress compared with AT. Thus, HNT was more devastating for grain quality than HDT. The exogenous application of PGRs ameliorated the adverse effects of high temperature in both rice cultivars, and Vc+Ve+MejA+Br was the best combination for both cultivars under high temperature stress.

Flax - Evaluation of composite flour and using in cereal products

Two types of yellow and brown linseed, differing in granulation, were tested in form of wheat flour composites (additions 2.5% and 5.0%) by using the Farinograph, the Extensigraph and the Rapid Visco Analyser (RVA) apparatuses. Additions of brown and yellow flax fibre significantly affected Falling Number and Zeleny test values. Curves of farinograph were differed according to flax fibre type - finer flax (better terminology) granulation meant somewhat stronger negative changes in dough stability and dough softening degree. Results of extensigraph test demonstrated changes in dough elasticity and extensibility due to lowering of gluten protein content. Appearance of the RVA profiles was verifiably different, reflecting diverse wheat and flax polysaccharides, added dietary fibre type and its granulation. Due to that, bread volume and shape was lowered up to one-half in case of golden flax composites. Similar tendencies with smaller negative influence caused the brown linseed. Fibre from flax is used for technical (textile) use, but linseed dietary fibre addition affected quality of laboratory prepared cut-off biscuits and dried pasta differently, showing a dependence on the fibre type, granulation as well as addition level. Sensory profiles of all mentioned product types were acceptable.

Predicting farinograph parameters by rapid visco analyser pasting profile using partial least square regression

Farinograph parameters are widely used to predict flour and dough functionality. Accurate prediction of farinograph parameters using other instruments would provide key information in determining cereal products quality and functional properties. This study was undertaken to provide calibration models using rapid visco analyser (RVA) to predict farinograph flour parameters and dough end-use functionality. A total of 267 samples consisted of wheat flour substituted with various ratios of disrupted chickpea (Cicer arietinum) and lentil (Lens culinaris) flours were used in this study. Samples (n=237) were randomly selected and used to develop calibration models of farinograph parameters using RVA profile. Another sample set consisting of 30 flour samples were used to validate the developed models. The partial least squares regression method using the RVA profile was used to develop prediction models for farinograph parameters treatments. Farinograph parameters (water absorption, peak time, mixing tolerance i...

A Comparison of Rapid Visco Analyzer Starch Pasting Curves and Test Baking for Under- and Overdosed Dry Baked Mixes

The rapid visco analyzer (RVA) is an analytical tool that measures the viscosity of food matrices, primarily starch-based products. In this study, RVA profiles for cake and cookie dry mixes that had been deliberately over- and underdosed with functional ingredients were evaluated. The pasting performance curves for the mixes demonstrated distinct characteristics for each sample type. Nonfat dry milk, cocoa, and vanilla treatments had minimal influence on pasting properties, whereas egg, baking soda, and sugar treatments significantly impacted pasting properties. The peak viscosity of the cake mix overdosed with egg was significantly greater than that of the mix underdosed with egg. The cake mix underdosed with sugar had a higher peak viscosity than the mix overdosed with sugar. The same trends were observed for the cookie mixes. A second experiment was conducted using only flour and a series of single ingredients. Sugar had the most significant impact on pasting, and peak viscosity was significantly lower...

Effects of dispersing media and heating rates on pasting profiles of wheat and gluten-free samples in relation to their solvent retention capacities and mixing properties

Four commercial wheat flours and two commercial GF bread mixtures were investigated in this study. The main aim was to find time-, cost- and sample-saving methods able to determine the quality characteristics of these materials in relation to their end-use and to the interactions taking place in the various systems. Samples were mainly characterized by Solvent Retention Capacity (SRC) and Rapid Visco-Analyser (RVA) tests. Mixogram and Confocal Laser Scanning Microscopy were adopted to investigate dough networking. In particular, RVA tests were performed adopting various heating rates and dispersing media, to: i) investigate how different heating/cooling rates could affect samples' pasting properties; ii) evaluate the role of alpha-amylase activity in controlling RVA profiles; iii) determine the contribution of proteins to RVA profiles. Interesting results were obtained in particular from SRC and RVA, suggesting that going beyond their conventional use as standard methods was feasible and very profitable. In fact, both the approaches well differentiated not only common and durum wheat flours but also the GF mixtures (e.g. WRC values ranged from 53.7 ± 0.1 to 152.1 ± 0.8 g/100 g db, and peak viscosity – measured at a heating rate of 3 °C/min – from 682 ± 72 cP to 4026 ± 11 cP).

Functional and Structural Properties of Corn, Potato, and Cassava Starches as Affected by a Single-Screw Extruder

The aim of this study was to identify suitable starch sources that can improve the structural integrity of plant protein-based extruded feeds, specifically aquatic feeds. Extrusion trials were performed, using a single-screw extruder. Extruder temperature, screw speed, and moisture content were varied in a factorial design with a replicated central composite point. The effects of these variables on functional and structural properties of the extrudates were evaluated. Temperature had the dominant effect on all properties. Increasing extruder temperature resulted in notable increases in onset temperature of gelatinization and glass transition temperature of all extrudates. The lowest water absorption, alkaline viscosity, and the highest water solubility, in addition to the lowest Rapid Visco Analyzer profile were found for corn starch extrudates. The lowest thermal stability was observed for the potato extrudate. It is expected that cassava and potato starches can contribute better in the formation of a cohesive structure and the generation of more expanded extrudates, specifically in the production of aquafeed. The higher enthalpy transition of corn extrudates indicated the higher thermal stability of corn starch which can lead in production of more durable aquafeed extrudates.

Differential expressions among five Waxy alleles and their effects on the eating and cooking qualities in specialty rice cultivars

Eating and cooking qualities (ECQs) of rice are important attributes due to its major influence on consumer acceptability. To better understand the molecular mechanism of the variation in ECQs, we investigated and compared the expressions among different alleles of the Waxy (Wx) gene and its effect on ECQs in specialty rice cultivars. The results showed that the accumulation of amylose was positively and significantly correlated to the level of mature Wx mRNA and granule-bound starch synthase I (GBSS I) in developing rice grain at 12 days after flowering. The amount of GBSS I and its activity together are the main factors controlling amylose synthesis. Differences in ECQs among five Wx allele types were investigated in samples from 15 rice varieties. The apparent amylose content (AAC) and gel consistency (GC) were similar in each type of Wx allele. The AAC followed the order, Wxa type>Wxin type>Wxb type>Wxmg type>wx. Contrary to this, the GC showed an opposite trend compared to AAC. There was a wide variation in rapid visco analyzer (RVA) profile among five Wx allele types, while varieties sharing a specified Wx allele had basically the similar RVA profile, although there was a slight difference in some RVA parameters, peak, hot paste and cool paste viscosities.

Gelatinisation kinetics of corn and chickpea starches using DSC, RVA and dynamic rheometry

The gelatinisation kinetics (non-isothermal) of corn and chickpea starches at different heating rates were calculated using differential scanning calorimetry (DSC), rapid visco analyser (RVA), and oscillatory dynamic rheometry. The data obtained from the DSC thermogram and the RVA profiles were fitted to Kissinger's and Ozawa's methods. Starch gelatinisation was characterised by two phases, where the first corresponded to the unfolding of amorphous region of the starch granule and the other represented the melting crystalline part. The temperature that separates the unfolding and melting of the granule parts, the breaking temperature, was recorded. Higher activation energy (Ea) was calculated for the DSC data versus the RVA. The Ea values calculated by Kissinger's method indicated that one can use either DSC or RVA to get a comparable Ea for both starches, whereas Ozawa's method showed comparable results for chickpea starch and less comparable for corn starch. The Ea of corn starch as calculated by dynami...

Application of Rapid Visco Analyser (RVA) viscograms and chemometrics for maize hardness characterisation

It has been established in this study that the Rapid Visco Analyser (RVA) can describe maize hardness, irrespective of the RVA profile, when used in association with appropriate multivariate data analysis techniques. Therefore, the RVA can complement or replace current and/or conventional methods as a hardness descriptor. Hardness modelling based on RVA viscograms was carried out using seven conventional hardness methods (hectoliter mass (HLM), hundred kernel mass (HKM), particle size index (PSI), percentage vitreous endosperm (%VE), protein content, percentage chop (%chop) and near infrared (NIR) spectroscopy) as references and three different RVA profiles (hard, soft and standard) as predictors. An approach using locally weighted partial least squares (LW-PLS) was followed to build the regression models. The resulted prediction errors (root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP)) for the quantification of hardness values were always lower or in the same order of the laboratory error of the reference method.

국내 육종 고구마 전분의 이화학 호화 및 소화 특성

Physicochemical, pasting, and digestion properties of sweet potato starches from 11 Korean cultivars were investigated. Starch granules were variably oval, round, polygonal, spherical, and bell-shaped, and of 10.2-15.3 μm in mean particle diameter. Amylose contents varied from 12.3 to 17.4%. A similar chain length distribution of amylopectin was found in each of the cultivars. The portion of B3 correlated with the degree of amylose leaching. Thermal properties determined by differential scanning calorimetry showed high values of gelatinization temperatures in Shinyulmi and Jeungmi starches, but a relatively low value in Daeyumi starch. All starches exhibited a Ca-type diffraction pattern. Differing patterns were observed in swelling factors, depending on temperature. The contents of rapidly digestible starch, slowly digestible starch, and resistant starch ranged from 9.6-17.4, 31.4-45.6, and 35.7-62.8%, respectively. In Rapid Visco Analyser profiles, differences were observed in pasting parameters such as pasting temperature, peak viscosity, final viscosity, and breakdown.

High-fiber date pits pudding: formulation, processing, and textural properties

The aim of this project was to prepare high-fiber pudding using date pits to meet the FDA requirement for health claim. Pudding desert was prepared with dates pits (DP), starch, sugar, xanthan gum (DX), flaxseeds gum (DF), and powdered milk. DP were milled, sieved through 149-µm sieve, and used for formulating high-fiber pudding. The pudding formulation included yeast, DX, or DF, and without gum (DP). Danette chocolate pudding, a commercial sample, was used as a reference. The formulation was cooked using rapid visco analyzer (RVA), and the gel was further analyzed by Brookfield viscometer and texture analyzer. The RVA profile of the formulation included peak viscosity, setback, and final viscosity. The data obtained from the RVA showed that pudding samples containing DX or DF gums exhibited higher peak viscosities (3,012.7 ± 22.5, 1,236.3 ± 110.9 cP, respectively) as compared to the DP pudding 735.3 ± 38.3 cP. The presence of DX instigated higher gel hardness than DF and DP, whereas DF caused higher cohesiveness than DP and DX. The shear stress as a function of shear rate profile indicated that DF was closer to Danette pudding sample. The consistency coefficient index (K), which was obtained from the power law, was higher for both DX and DF, indicating higher viscosity, whereas lower flow behavior index (n) signifies a more pseudoplastic system of these samples. Based on the Ea values, it can be concluded that DX sample is less temperature dependent (lower Ea) than DF (higher Ea). The sensory testing showed that yeast treatment brought the formulation closer to the control in terms of panel acceptance.

Effect of sucrose fatty acid esters on pasting, rheological properties and freeze–thaw stability of rice flour

The present research is aimed to evaluate the effects of sucrose fatty acid esters (SEs) on the pasting, rheological properties and the freeze–thaw stability of rice flour. Four types of SEs including S-570, S-970, S-1170 and S-1570 with hydrophilic–lipophilic balance (HLB) values varying from 5 to 15 have been compared. Viscosity behavior of rice flour with different SEs was first measured with the Rapid Visco Analyzer (RVA). The RVA profile showed that pasting temperature, peak and final viscosities of rice flour gels increased with SEs addition except for S-570. Rheological properties including the steady shear characteristics, the viscoelastic parameters (storage and loss moduli) and the creep-recovery response were determined. The obtained steady shear and creep data were fitted by power law (R2 > 0.983) and Burger's models (R2 > 0.993) respectively. The results revealed that the addition of SEs except for S-570 increased the storage and loss moduli, apparent viscosity, flow behavior index and the retardation time, and decreased loss tangent. Finally, the freeze–thaw measurement demonstrated that all types of SEs enhanced the freeze–thaw stability of rice flour with the order of S-1570 > S-1170 > S-970 > S-570. These results could have important theoretical and practical implications in choosing suitable SEs for the particular requirements of final food products based on rice flour.

Correlations between RVA profile properties and main qualities ofindicahybrid rice

To study the correlations between RVA (Rapid Visco Analyzer) profile properties and the main qualities of indica hybrid rice, a set of 104 different amylose content (AC) indica hybrid rice combinations was grown at Chang'an experimental station of Hunan Agricultural University, Hunan province, China during May to October 2011. The results indicated that the correlations between RVA profile properties with appearance quality and cooking quality were close. The grain length and grain length/width were positively correlated with final viscosity, setback viscosity, peak time, consistency viscosity, respectively (P<0.01) but negatively with peak viscosity and breakdown viscosity, respectively (P<0.01). Translucency had significant positive correlations with peak viscosity and breakdown viscosity, respectively (P<0.01) but negative correlation with setback viscosity, peak time (P<0.01) and consistency viscosity (P<0.05). The amylose content, alkali-spreading value and protein content were negatively correlated with peak viscosity, breakdown viscosity, respectively, but positively correlated with setback viscosity and peak time, respectively (P<0.01), but the gel consistency was vice versa. RVA profile properties can reflect the good or bad of rice quality. Varieties with different AC had different RVA profile properties, when AC was higher, setback viscosity, peak time and consistency consistency were higher, while peak viscosity and breakdown viscosity were lower. The AC in different rice varieties with different AC levels had obviously different correlations with each indicator of RVA properties. The hybrid rice combinations with different AC were categorized first based on their AC level before analyzing the correlations between AC and RVA profile properties. RVA profile properties can reflect the differences in cooking quality among hybrid rice combinations with similar amylose content from low-mid-level (15%=AC≤17%) to mid-level (17%≤AC≤22%).