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

Background The 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. Results Quantitative 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. Conclusions By 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.

Bond Properties of NHL-Based Mortars with Viscosity-Modifying Water-Retentive Admixtures

This article studies the influence of biopolymeric viscosity-modifying admixtures with water-retentive function on the physico-mechanical properties of natural hydraulic lime-based mortars and their adherence to the traditional fired-clay brick substrate. The use of admixtures increases the water/binder ratio, which in turn leads to a decrease in the strength of the mortars. The viscosity-modifying function improves the adhesive strength between mortar and pre-wetter brick by increasing the binder paste viscosity, while the water-retentive function along with increased water content may lead to a decrease in adhesive strength. On the contrary, water retention and increased water content are beneficial on a dry surface, while paste viscosity plays only a minor role. When subjected to temperature-varying cycles, the mortars are more prone to in-mortar failure during the pull-off test. The air-entraining function of some admixtures improves the frost resistance of the mortars; however, it would negatively affect the adhesive strength by incorporating pores into the contact zone between the mortar and brick substrate. This study showed that the use of some of the studied admixtures may improve the adhesion of mortar to the brick substrate.

Resistant Starch Contents of Starch Isolated from Black Longan Seeds

A large quantity of longan fruits (Dimocarpus longan Lour.) produced annually are processed into many products, one of which is black longan, from which the dried, dark-brown meat has been used medicinally in traditional medicine, while the starch-containing seeds are discarded. In this study, starch samples (BLGSs) were isolated from seeds of black longan fruits prepared using varied conditions. The in vitro digestibility was determined in comparison with those extracted from fresh (FLGS) and dried (DLGS) seeds. Scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy were employed to evaluate the starch properties. The results showed that the yields of FLGS, DLGS, and BLGSs were 20%, 23%, and 16–22% w/w, respectively. SEM images showed starch granules of mixed shapes, with sizes up to 15 µm in all samples. XRD patterns confirmed an A-type crystallinity for FLGS and DLGS, with strong refraction peaks at 2θ = 15°, 17°, 18°, and 23°, while BLGSs also showed detectable peaks at 2θ = 10° and 21°, which suggested V-type structures. Thermal properties corroborated the changes by showing increases in peak gelatinization temperature (Tp) and enthalpy energy (ΔH) in BLGSs. The paste viscosity of BLGSs (5% w/w) decreased by 20–58% from that of FLGS. The FTIR peak ratio at 1045/1022 and 1022/995 cm−1 also indicated an increase in ordered structure in BLGSs compared to FLGS. The significant increase in the amounts of slowly digestible starch (SDS) and resistant starch (RS) in BLGSs compared to FLGS, especially at a prolonged incubation time of 20 (4.2×) and 30 days (4.1×), was proposed to be due to the heat-induced formation of starch inclusion with other components inside the seed during the black longan production process. Thus, black longan seed could be a new source of starch, with increased RS content, for potential use in the food and related industries.

Impact of Sulphate Ions Content on Performance of Maleic and Acrylic Superplasticizers in Cement Paste

The paper presents test results of the impact of sulphate ions from calcium sulphates: Hemihydrate, dihydrate and anhydrite, on rheological properties and hydration heat of cement pastes with, and without, superplasticizers, derivatives of maleic (SP-2) and acrylic (SP-1) acids. It is demonstrated that cement pastes fluidity depends on superplasticizer chemical structure, and its effect is expressed by a hydrophilic coefficient. As maleic superplasticizers have flexible comb-like structure composed of a shorter backbone chain containing COO− carboxylate groups and very long side chains, cement pastes showed higher fluidity than with acrylic superplasticizer with ladder-like structure, longer backbone chains with shorter side chains. SP-1 showing lower hydrophilicity coefficient and fewer COO− groups was found to be less sensitive to increased sulphate ion content in pastes. However, with SP-2 with higher hydrophilicity, a gradual fluidity loss (increased paste viscosity) was observed. Plastic viscosity was approximately at the same level in SP-1-containing pastes. Tests showed that sulphates definitely changed polycarboxylate superplasticizers performance. A high concentration of sulphate ions reduced maleic superplasticizer efficiency. Under these conditions, SP-1 is more effective and therefore more suitable for fluidity of pastes containing higher SO42− ions content. Thus, sulphate ions concentration in the paste should be considered when selecting superplasticizer.

Use of Amylomaltase to Steer the Functional and Nutritional Properties of Wheat Starch

The fine molecular structure of starch governs its functionality and digestibility, and enzymatic approaches can be utilized to tailor its properties. The aim of this study was to investigate the in situ modification of starch by amylomaltase (AMM) from Thermus thermophilus in model starch systems subjected to hydrothermal treatments under standardized conditions and the relationship between molecular structure, rheological properties and in vitro digestibility. When low dosages of AMM were added to a wheat starch suspension prior to submitting it to a temperature-time profile in a Rapid Visco Analyzer, the increased peak viscosity observed was attributed to partial depolymerization of amylose, which facilitated starch swelling and viscosity development. At higher dosages, the effect was smaller. The low cold paste viscosity as a result of the activity of AMM reflected substantial amylose depolymerization. At the same time, amylopectin chains were substantially elongated. The longer amylopectin chains were positively correlated (R2 = 0.96) with the melting enthalpies of retrograded starches, which, in turn, were negatively correlated with the extent (R2 = 0.92) and rate (R2 = 0.79) of in vitro digestion. It was concluded that AMM has the potential to be used to deliver novel starch functionalities and enhance its nutritional properties.

QTL Mapping for the Starch Paste Viscosity of Rice (Oryza Sativa L.) Using a Chromosome Segment Substitution Lines Derived From Two Sequenced Cultivars With Same Wx Allele

BackgroundEating and cooking qualities (ECQs) of rice (Oryza sativa L.) is one of the most important economic characters which affecting production and market value. The starch viscosity profile tested by Rapid visco analyzer (RVA) is the direct measure of ECQs that represents the changes in viscosity associated with starch gelatinization. RVA profiles of rice are controlled by a complex genetic system and affected by environment. It is necessary to identify genetic factors controlled the RVA profile characters for development of rice varieties with excellent ECQs. Although it is known that Waxy (Wx) is the major gene control the amylose content (AC) and ECQs, there still have other unknown genetic factors effecting on ECQs.ResultsQuantitative trait loci (QTL) for starch paste viscosity of rice was analyzed using chromosome segment substitution lines (CSSLs) developed from 9311 and Nipponbare with same Wx-b background. With this CSSLs, the effect of major locus Wx could be eliminated and the other locus associated with RVA profile could be identified. QTLs for seven traits of starch RVA profile were tested over 4 years in Nanjing, China. 310 QTLs were identified (from 1 to 55 QTLs for each trait). Among 136 repeated QTLs, 6 QTLs were stable and detected every year. In total of 26 marker intervals detected over 3 years or more, 13 showed pleiotropy with respect to controlling 2 to 6 starch RVA profile properties simultaneously. The stable QTL clusters which we mapped here were overlapped to some of the known starch synthesis–related genes (SSRGs). ConclusionsWithout the effect of major locus Wx, many QTLs associated with RVA profile of rice were identified and some of them were stable. Our study illustrated that the hereditary of rice starch RVA profile is complicated, pleiotropic effects and QTL hot spots are the key factors affecting starch RVA traits.

Functionality of cassava genotypes for waxy starch

The objective of this work was to select cassava (Manihot esculenta) genotypes from the Brazilian germplasm bank with a functionality similar to that of waxy starch. A total of 881 genotypes were pre-selected using principal component analysis and hierarchical clustering, and their industrial potential was compared with that of the 7745-5WX waxy cassava and the WX-Maize waxy maize clones, both used as references. Two genotypes stood out: BGM0036 and BGM0083. Samples from these four genotypes were characterized by means of amylose content, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, paste viscosity, and chain-length distribution of amylopectin. The samples presented A-type crystallinity and no statistical differences (p > 0.05) regarding crystallinity degree (25.3 to 30.0), which shows similar proportions of the amylose/amylopectin fractions. No differences were observed in the microstructure of the cassava starches. Initial gelatinization temperature and amylopectin short chains presented a very strong negative correlation, indicating that a lower proportion of short chains of amylopectin results in a higher initial temperature of gelatinization. BGM0036 and BGM0083 show a low final viscosity, close to that of the waxy maize and cassava starches, being an alternative for use in different foods that require stability during freezing.

Effects of soluble starch synthase genes on eating and cooking quality in semi waxy japonica rice with Wxmp

The purpose of this study is to reveal the genetic mechanism of the variation of amylose content among different semi waxy or glutinous japonica rice in the background of Wxmp gene. Sixty-four semi waxy lines derived from the hybrid progenies of Wujing 13 and Milky Princess (Kantou 194) with polymorphism in soluble starch synthase gene SSIIa (SSII-3) and SSIIIa (SSIII-2) but no polymorphism in other starch synthase related genes were used as test materials. The genotypes of SSIIa and SSIIIa allele were identified by molecular markers, and the allelic effects of SSIIa and SSIIIa gene on amylose content (AC), gel consistency (GC), gelatinization temperature (GT) and rapid visco analyzer (RVA) profile characteristics were analyzed. The significant effects of SSIIa and SSIIIa alleles and the interactive effects between two genes on AC, GT, GC and RVA profile characteristics were found. The SSIIa and SSIIIa alleles from Wujing13 shown positive effects on AC with an average increase of 1.87 and 1.23% in 2 years respectively. There was no significant effect on GT for SSIIa or SSIIIa allele but remarkable influence on GT when the co-existence of the two genes. The genotype SSIIampSSIIIamp shown 1.34 °C higher GT than genotype SSIIawjSSIIIawj (mp and wj indicated that the gene was derived from Milky Princess and Wujing 13 respectively, the same as in the below). Different genes and alleles resulted in significant different GC. The genetic effect of SSIIawj and SSIIIamp on GC was 8.74 and 9.62 mm respectively. The GC of SSIIawjSSIIIamp was 10.64 and 16.95 mm higher than that of SSIIampSSIIIawj and SSIIawjSSIIIawj, respectively. The allele SSIIawj could increase the peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV) and breakdown viscosity (BDV), while decrease the consistency viscosity (CSV) and setback viscosity (SBV). However for the allele SSIIIawj the opposite was true. The genotype SSIIawjSSIIIamp had the largest PKV, HPV and CPV, the genotype SSIIawjSSIIIawj had the largest BDV and CSV, but the genotype SSIIawjSSIIIamp had the least SBV. According to the comprehensive effect of each trait, the genotype SSIIawjSSIIIamp was the best. The allelic variation and interaction effect of SSIIa and SSIIIa genes have important reference value for improving cooking and eating quality of semi waxy japonica rice.

Reduction of Aflatoxin B1 in Corn by Water-Assisted Microwaves Treatment and Its Effects on Corn Quality

Aflatoxin B1 (AFB1) is one of the most commonly found mycotoxin in corn, which is highly toxic, carcinogenic, teratogenic, and mutagenic for the health of humans and animals. In order to reduce the AFB1 in corn, corn kernels were processed with Water-assisted Microwaves Treatment (WMT) and the feasibility of WMT processing on AFB1 reduction and its effects on corn quality were analyzed. Increasing the treatment time and microwave power could increase the reduction of AFB1, and the maximum reduction rate could reach 58.6% and 56.8%, respectively. There was no significant correlation between the initial concentration of AFB1 and the reduction rate of AFB1. During WMT, the main toxigenic molds were sterilized completely, and the moisture content of corn climbed up and then declined to the initial level. WMT could obviously increase the fatty acid value and pasting temperature of corn and reduce the all paste viscosity of corn. However, it had little effect on the color of corn. The results indicated that WMT could reduce AFB1 effectively and avoid the vast appearance of heat-damaged kernels simultaneously. Undoubtedly, water played an important role in WMT. This result provides a new idea for the reduction of AFB1 by microwave.

PENGARUH KONSENTRASI STPP DAN LAMA PERENDAMAN TERHADAP KARAKTERISTIK PATI KIMPUL TERMODIFIKASI IKATAN SILANG

Kimpul is one type of tubers that is high in carbohydrate content so it canbe used as a source of starch. Natural starch generally still has severaldisadvantages. One of method that can be done to overcome theseweaknesses is by modifying cross-linked starch. The objectives of thisstudy are: 1) to know the effect of STPP concentration on chemical andphysical characteristics of modified kimpul starch; 2) to know the effect ofsoaking time on chemical and physical characteristics of modified kimpulstarch; 3) to determine the best combination treatment between STPPconcentration and soaking time on the chemical and physicalcharacteristics of modified kimpul starches. This is an experimentalresearch with Randomized Block Design. The factors studied were theconcentration of sodium trypolyphosphate (1, 2 and 3%) and soaking time(60 and 90 minutes). The variables tested were moisture content, starchcontent, amylose content and calcium oxalate content, brightness, swellingpower, sollubility and its amylographic properties. The results showedthat both STPP concentration factors and soaking time affected themodified chemical and physical characteristics of kimpul starchcrosslinking methods. The chemical and physical characteristics of crossbonded modified kimpul starch increased with STPP concentration andsoaking time used. Modified kimpul starch using 3% STPP concentrationand 90 minutes soaking time had moisture content, starch content, amylosecontent, calcium oxalate content, brightness and high swelling power. Thebest modified kimpul starch is modified kimpul starch using 2% STPPconcentration and 60 minutes soaking time. It has a water content of7,88%, starch content of 63,13%, amylose content of 17,28%, oxalatecontent of 15,84 ppm, swelling power 15,79 g/g, sollubility 11,55%,brightness of 44.13, initial gelatinization temperature of 78,75oC, peakviscosity of 5152.5 cP, hot paste viscosity of 2310,4 cP, breakdownviscosity of 2815 cP, setback viscosity of 1563 cP and cold paste viscosityof 3873,5 cP