Pasting Peak Viscosity Research Articles

Effects of galactomannans of varied structural features on the functional characteristics and in vitro digestibility of wheat starch

This study explores the effects of four natural galactomannans (GMs) with varying degrees of branching (fenugreek gum, guar gum, tara gum and locust bean gum) on the functional properties and in vitro digestibility of wheat starch (WS). Results from rapid viscosity analysis (RVA) and low-field nuclear magnetic resonance (LF-NMR) analysis revealed that GMs with lower branching degrees were correlated with higher paste viscosity, peak viscosity, and greater water-holding capacity in the WS-GM mixtures. Additionally, these lower branching GMs more effectively inhibited amylose leaching during starch gelatinization, leading to a softer gel texture and increased transparency of the mixtures. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis demonstrated that starch mixtures containing lower branching GMs exhibited reduced relative crystallinity and enthalpy values during aging. Furthermore, the incorporation of lower branching GMs resulted in decreased starch digestibility in vitro, thereby enhanced resistant starch content. These findings highlight the potential of selectively branched GMs to modulate the functional properties and nutritional profile of WS, providing a promising approach for the development of starch-based products with improved health benefits.

Effect of Bambara Groundnut Flour (Vigna subterranea) Inclusion on the Functional, Pasting, Physical and Proximate Properties of Composite Cassava-bambara Flour

This study evaluated the effect of Bambara groundnut flour inclusion on the functional, pasting, physical properties and proximate compositions of composite flour (CF) from cassava and Bambara groundnut. Cassava variety (IITA-TMS-IBA011368) and Bambara groundnut were processed into flour and blended together based on D-Optimal mixture design with an outcome of eight experimental samples using Design Expert Software (Version 12.0). The flour blends were analyzed for functional, pasting, physical properties (color), baking strength and proximate composition. Data obtained were analyzed using analysis of variance and means were separated using Ducan’s Multiple Range Test. Range of results for bulk density, water absorption capacity, swelling index, solubility index and oil absorption capacity of the composite flour are 0.64-0.80g/mL, 0.38-1.37%, 0.77-0.91%, 6.00-8.65, 1.58-2.97, respectively. The peak viscosity, trough, breakdown viscosity, final viscosity, setback viscosity, peak time and pasting temperature ranged from 162.84±2.09 to 426.50±1.83 RVU, 77.96±2.71 to 195.59±8.91 RVU, 84.88±0.63 to 234.75±5.58 RVU, 158.92±4.34 to 293.17±1.34 RVU, 76.88±18.04 to 101.42±5.08 RVU, 4.10±0.03 to 5.93±0.00 min and 75.05±0.05 to 94.78±0.38 oC, respectively. The baking strength characteristics of the flour blends such as moisture, ash, color, wet gluten, zenleny dry protein and wet protein ranged from 11.55 to 12.55%, 0.50 to 1.25%, 88.65 to 90.55, 8.35 to 13.80, -2.35 to 41.25, 4.92 to 13.85% and 4.53 to 11.99 %, respectively. Moisture, ash, fibre, fat, protein and carbohydrate of the composite flour ranged from 7.57 to 11.87%, 0.42 to 2.40 %, 1.78 to 3.00%, 2.81 to 5.62%, 8.42 to 12.68% and 67.61 to75.99%, respectively. Flour lightness, redness and yellowness ranged from 33.22 to 54.10, -2.89 to-1.14, 5.94 to 9.35, respectively. The inclusion of Bambara groundnut flour had a significant effect on the functional (swelling index, water and oil absorption capacity), pasting (peak, trough and final viscosity) and proximate (ash, fat and carbohydrate) properties of the flour blends.

Changes in the pasting and rheological properties of wheat, corn, water caltrop and lotus rhizome starches by the addition of Annona montana mucilage

Annona montana mucilage (AMM) is a novel mucilage with unique but limited information. This study investigated the effects of AMM addition on the pasting and rheological properties of wheat starch (WS), corn starch (CS), water caltrop starch (WCS), and lotus rhizome starch (LRS). The addition of AMM generally increased the pasting temperature and peak viscosity, but reduced the setback value of all starches to varying degrees, and the initiation of viscosity-increase for cereal starch/AMM systems during pasting occurred at lower temperatures, accompanied with a distinctive two-stage swelling process as well as lower peak and final hot paste viscosity at 50 °C. AMM significantly increased the pseudoplasticity and entanglement of the systems to varying degrees (LRS > WS > WCS > CS). Under a constant shear rate of 50 s−1, the consistency level was found to fall in honey-like for cereal starch/AMM groups, and honey-like to extremely thick levels for WCS and LRS/AMM groups. Except for the WCS/AMM systems, the storage and loss modulus as well as tanδ increased with increasing AMM concentration. Short-term retrogradation of starch at 4 °C was pronouncedly retarded by the addition of AMM for WS, CS and WCS groups, but was less affected for LRS group.

Influence of Postharvest Natural Softening Conditions on the Nutritional Quality of Safou (Dacryodes edulis H.J.Lam) Flour: Rheological Properties of the Optimized Safou Flour.

Safou (Dacryodes edulis H.J.Lam) is a seasonal fruit of great importance in the diet and economy of the populations of safou-producing countries. However, the valorization of this fruit is limited due to postharvest losses linked to the softening of the fruit, though this fruit is an essential source of macro- and micronutrients. Thus, this study is aimed at contributing to the valorization of softened safou by determining the optimum softening time, drying time, and temperature for good nutritional and rheological flour. The effects of the softening time, drying time, and drying temperature on the fat, protein, carbohydrate, dietary fibre, water, calcium, phosphorus, and potassium content were studied using the central composite design. The results showed that all the responses were affected by the factors. Also, the softening time of 4.75 days, drying time of 40.55 hours, and drying temperature of 41.83°C were the optimum conditions for producing safou flour with high nutritional value and good rheological properties. These optimum conditions resulted in safou flour with 58.95%, 12.40%, 22.40%, 4.38%, 4.91%, 2207.90 mg/1000 mg, 1898.30 mg/1000 mg, and 478.540 mg/1000 mg as lipid, protein, carbohydrates, fibre, moisture calcium, phosphorus, and potassium content, respectively. In addition, the pasting temperature, peak viscosity, breakdown, holding viscosity, final viscosity, setback, setback ratio, and stability ratio of the aforementioned flour were 50.42°C, 58 cp, 0.5 cp, 57.5 cp, 61.5 cp, 4 cp, 1.07, and 1, respectively. Based on its nutritional value and rheological properties, softened safou flour can be used in food formulation, thus contributing to the valorization of safou fruits.

Biophysical and textural attributes as selection indices for replacing the adopted cassava variety with the improved genotype to produce fufu

The use of the biophysical and textural qualities of fufu to choose the possible substitution of an adopted cassava variety (TMEB419-V1) with improved genotypes from the breeding program was assessed in this study. Standard methods were used for the biophysical and textural attributes of the fufu produced from different cassava roots. The outcomes portray that the means of the biophysical attributes of the fufu flour from different cassava genotypes are swelling power (SWP) of 13.59%, solubility index (SI) of 3.41%, dispersibility of 26.77%, bulk density (BD) of 54.46%, water absorption capacity (WAC) of 149.44%, peak viscosity of 693.97 RVU, trough viscosity of 319.76 RVU, breakdown viscosity of 374.21 RVU, final viscosity of 433.84 RVU, setback viscosity of 114.08 RVU, peak time of 4.49 min, and pasting temperature of 78.52°C, as well as moisture content of 4.92%, ash content of 0.52%, sugar content of 2.85%, starch content of 76.24%, amylose content of 31.68%, and cyanogenic potential content (CNP) of 3.03 mg HCN/kg. The sensory texture attributes depict that the cooked fufu dough was stretchable, slightly hard, sticky, and mouldable. The instrumental texture attribute of the cooked fufu dough is hardness 27.18 N/m2, adhesiveness −62.04 N/m2, moldability 0.93, stretchability 0.89, and gumminess 25.26 N/m2. Similar functional (BD) and pasting (peak and breakdown viscosities) properties and chemical composition (amylose content) to that of the control sample (V1 variety) were produced from the V6 genotype. However, the cooked fufu dough prepared from the V7 and V8 genotypes was comparable to that of the V1 variety in terms of the sensory (stretchability) and instrumental (moldability) texture attributes; therefore, most of the genotypes may be suitable for producing fufu flour like the control sample (V1 variety) based on attributes preferred by the consumers.

Lily Starch—An Underutilized and Non‐Conventional Source: Properties and Applications

AbstractLily belongs to the genus Lilium of the family Liliaceae. Starch is the main component of lily bulbs which accounts for 53–69% of their dry weight. Lily starch (LS) has B‐type X‐ray diffraction characterized by a peak at 5.6°, 17°, 22°, and 24°. The swelling and solubility of the LS are significantly higher than rice and corn starches. The gelatinization temperatures of the LS are much lower than maize but higher than wheat and potato starches. The pasting temperature, peak, breakdown, and setback viscosities of lily starches are falling within the range; 66.1–72.7 °C, 1409–3940 cP, 88–1206 cP, and 445–1952 cP, respectively. The range for initial temperature, gelatinization temperature range, and enthalpy for lily starches is also 56.5–64.0 °C, 3.8–10.3 °C, and 3.9–13.9 J g−1, respectively. This review focuses on the recent advances in the understanding of the composition, structure, and properties of lily starches. Furthermore, the limited modification associated with lily starches is also discussed. There is a bold attempt to compare the properties of lily starch with that of the commercial starches of corn and potato.

Extraction and characterisation of avocado seed starch (Persea americana Miller) and application in aerogels

SummaryAvocado seed (Persea americana Miller) is a by‐product of fruit processing and is considered a potential alternative source of starch. The use of starches from unconventional sources can be an alternative to replace modified starches as a functional ingredient in food systems. This study aimed to extract and characterise starch from avocado seed varieties Fortuna and Hass and produce aerogels. Starches were characterised by physical, chemical, thermal and morphological properties. The aerogels were produced by physical crosslinking and evaluated for water absorption capacity and physical properties. The starch extraction yield was 12%, and the granules had oval and spherical morphology. Amylose content ranged from 41.95% to 49.46%, and relative crystallinity from 22% to 25% for Hass and Fortuna, respectively. The Fortuna starch showed higher pasting temperature, peak viscosity, peak time and final viscosity values. Aerogels had excellent structural characteristics and had not deformed after 24 h of hydration; the Fortuna starch aerogels showed higher water absorption and mechanical resistance. The properties of avocado seed starch indicate a vast potential for application in food industries and for developing biodegradable packaging with excellent physical properties and excellent water retention capacity.

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.

Chemical, functional, rheological and structural properties of broken rice–barnyard millet–green gram grits blend for the production of extrudates

AbstractBroken rice is an underutilized by‐product of the rice milling industry. It was added with green gram and barnyard millet to investigate as a source of nutrition‐based value‐added food product. The study was carried out to examine the influence of formulated composite flour obtained from broken rice (Oryza sativa) (50%–80%), barnyard millet (Echinochloa esculenta) (10%–30%), and green gram (Vigna radiata) (10%–30%) on the chemical properties, functional properties, pasting properties, oscillatory test, flour behavior, and microstructure of extrudate. The ash, crude fiber, crude protein, fat, and carbohydrate of the extrudate ranged from 1.62%–1.78%, 1.88%–2.43%, 13.47%–14.57%, 4.9%–7.48%, and 66.86%–70.8%, respectively. The water absorption index (WAI) and water solubility index (WSI) for the flour ranged from 5.06%–6.18 g/g and 2.34%–3.99%. The formulated composite flours having a higher percentage of broken rice showed significant differences (p < 0.05) in their pasting properties, pasting temperature, peak viscosity, breakdown viscosity, and setback and final viscosity. The pasting properties gave better results using a twin‐screw extruder with operating conditions of barrel temperature of 110°C, screw speed of 290 rpm, and 14% moisture content (w.b.). The microstructure of the extrudate obtained from 80% broken rice, 10% barnyard millet, and 10% green gram grits flour possessed a more integrated, well‐defined porosity, indicating a completely gelatinized structure.Practical applicationDetermination of biochemical, structural, and rheological properties of ingredients are essential for the production desirable ready‐to‐eat snacks. In this context, the present study evaluated the functional and rheological properties of broken rice–barnyard millet–green gram blend for the production of nutritious snacks with desirable physical and textural properties. The findings of the study would be useful for food products industries using millets and broken rice as a major raw material.

Characterization of Yield-Related Traits and Pasting and Texture Properties of Glutinous Rice Cultivars by Cultivation Times in the Honam Plain, Korea

Other SectionsAbstractThe cultivated area of glutinous rice in the Homan Plain of Korea is increasing to diversify the cropping system. Depending on the time of transplanting, glutinous rice can be divided into early, ordinary, and late cultivation. Eight glutinous rice cultivars (Baegseolchal, Baekogchal, Boramchal, Boseogchal, Dongjinchal, JJ644wx, Nunbora, and Sinseonchal) were used to evaluate yield, pasting properties, and texture according to cultivation time and to analyze the genotype-environment relationship. There were nine yield-related, six pasting-related, and four texture-related traits studied. Heading date and culm length were shortened as cultivation time increased, while panicle length, number of spikelets, and 1,000-grain weight increased. Furthermore, late cultivation time also reduced pasting properties, peak viscosity, trough viscosity, and final viscosity. Hardness and adhesiveness among the texture properties increased with cultivation time, but stickiness decreased. The variation in 1,000-grain weight is mostly dominated by genotype, whereas heading date and yield are heavily influenced by environmental factors. All pasting property characteristics varied with environment changes, and genotype variation was dominant for all texture properties. Boramchal yielded the most in early and ordinary cultivation and Sinseonchal, together with Boramchal, yielded the most in late cultivation. Cultivars with excellent grain quality were Sinseonchal in early cultivation and Baegseolchal and Baekogchal in ordinary and late cultivation. A comparative analysis of characteristics based on cultivation time can assist in the selection of glutinous rice suitable for the Honam Plain and in the breeding of cultivars with improved yield and excellent grain quality.Keywords : breeding, glutinous rice, yield, pasting property, texture property

Pasting and rheological properties of water caltrop starch as affected by the addition of konjac glucomannan, guar gum and xanthan gum

Water caltrop starch (WCS) isolated from the dehydrated water caltrop (DWCS) showed higher content of protein and ash as compared to starch isolated from fresh water caltrop (FWCS), leading to slightly lower starch purity. However, the pasting profiles of DWCS and FWCS are similar under a constant solid content of 4% (w/w). WCS/gum mixed systems contain 0.3%–0.9% gum generally showed higher pasting temperature, peak viscosity, and final viscosity than the starch alone system. The increase in peak and final viscosity during rapid-viscosity analysis was most pronounced for WCS/gum mixed systems with konjac glucomannan (KG), followed by guar gum (GG) and xanthan gum (XG). All WCS/gum mixed systems showed shear thinning and thixotropic characteristics. The extent of pseudoplasticity and shear stability, as evidenced by the smaller flow behavior index (n) and area of the hysteresis loop, was most pronounced for WCS/gum mixed system with XG, followed by mixed systems with GG and KG. Dynamic viscoelastic analysis revealed that the addition of gum increased both the storage and loss moduli of WCS, and lowered the frequency dependence of the loss factor significantly. However, the loss factor of WCS/gum mixed systems was generally higher than that of the starch alone system, implying the addition of gums modified the rheological characteristic of WCS to more viscous dominant behavior.

Effect of Bioprocessing on Techno-Functional Properties of Climate-Resilient African Crops, Sorghum and Cowpea.

Sorghum and cowpea are very compatible for intercropping in hot and dry environments, and they also have complementary nutritional compositions. Thus, the crops have the potential to improve food security in regions threatened by climate change. The aim of this study was to investigate different enzymes (carbohydrate-degrading, proteases and phytases) and lactic acid bacteria (LAB) fermentation to improve the techno-functional properties of sorghum and cowpea flours. Results show that sorghum carbohydrates were very resistant to hydrolysis induced by bioprocessing treatments. Most of the protease treatments resulted in low or moderate protein solubilization (from ca. 6.5% to 10%) in sorghum, while the pH adjustment to 8 followed by alkaline protease increased solubility to 40%. With cowpea, protease treatment combined with carbohydrate-degrading enzymes increased the solubility of proteins from 37% up to 61%. With regard to the techno-functional properties, LAB and amylase treatment decreased the sorghum peak paste viscosities (from 504 to 370 and 325 cPa, respectively), while LAB and chemical acidification increased cowpea viscosity (from 282 to 366 and 468 cPa, respectively). When the bioprocessed sorghum and cowpea were tested in breadmaking, only moderate effects were observed, suggesting that the modifications by enzymes and fermentation were not strong enough to improve breadmaking.

Influence of Mutant Wx‐D1f Allele on Synthesis of Amylose and Extra‐Long Chains of Amylopectin in Wheat (Triticum aestivum L.)

AbstractWaxy wheat lines carrying null alleles at the loci Wx‐A1 and Wx‐B1 and a mutated Wx‐D1 allele (Wx‐D1f) generate unique pasting curves on a Rapid Visco Analyzer. The initial pasting temperature, peak viscosity, and final viscosity are found to not differ markedly between waxy wheat carrying Wx‐D1b and waxy wheat carrying Wx‐D1f, but the hot‐paste viscosity is more stable in the case of waxy wheat carrying Wx‐D1f. The study seeks to determine the cause for this unique starch property. Whereas amylopectin chain‐length distribution is similar in wheat lines #211 (Wx‐A1b, Wx‐B1b, Wx‐D1a) and #234 (Wx‐A1b, Wx‐B1b, Wx‐D1f), #234 contained 7.0% amylose and 1.3% extra‐long chains (ELCs) of amylopectin, levels corresponding to 1/3 and 2/3 of the content of amylose and ELCs of amylopectin in #211, respectively. Moreover, #234 contains a small‐chain amylose not detected in #211. Therefore, this study concludes that the unique starch characteristics of waxy wheat carrying Wx‐D1f may be due to the relatively high quantity of ELCs of amylopectin and/or the low‐molecular‐weight amylose.

Impact of gamma irradiation on structural, thermal, and rheological properties of talipot palm (Corypha umbraculifera L.) starch: a stem starch

Talipot palm (Corypha umbraculifera L.) is a non-conventional source of stem starch. The starch obtained from the trunk of the talipot palm was subjected to various doses of irradiation (20 kGy, 50 kGy, 80 kGy, and 100 kGy). The effect of this high dose irradiation on functional, pasting, thermal and rheological properties was studied. The irradiation considerably decreased the amylose content, pH, swelling index, and relative crystallinity, and it increased the carboxyl content and solubility. The L* value, water absorption capacity, and oil absorption capacity were also increased by irradiation. The pasting parameters like pasting temperature, peak viscosity, and final viscosity were considerably decreased by irradiation. The paste clarity and light transmittance of irradiated starches were high at any point of storage. The gel hardness was decreased by γ-irradiation up to a radiation dose of 50 kGy. The FTIR analysis did not show any evidence for the formation of new functional groups. The gelatinization properties, storage modulus, and loss modulus were decreased by irradiation. The principal component analysis showed a good relationship among the different parameters studied.

Physicochemical properties and viscoelastic behavior of rice–mung bean composite flour systems as potential ingredients for plant‐based foods

AbstractBackground and ObjectivesComposite flour (CF) from cereals and legumes has been used to formulate plant‐based and/or gluten‐free food products. Fundamental knowledge regarding the properties of CF is required to formulate food products with desirable qualities. This study aimed to investigate the pasting properties, thermal properties, and viscoelastic behavior of CF, containing rice flour (RF), mung bean flour (MF), and mung bean protein concentrate (MPC). The protein contents of the CF were 17.6%‐23.6% on a wet basis.FindingsThe CF containing the highest proportion of RF had the highest pasting temperature, peak viscosity, breakdown, setback, and melting enthalpy of retrograded amylopectin. The deconvoluted thermogram from differential scanning calorimetry (DSC) clearly distinguished the endotherms that arose from starch gelatinization, protein denaturation, and melting of the amylose−lipid complex. The gelatinization endotherm of CF was mainly governed by RF. CF containing a higher proportion of RF and MPC had stronger elastic behavior.ConclusionsThe type and composition of the flour greatly affected the physicochemical and viscoelastic properties of the CF. RF played an important role in the pasting and thermal properties of the CF samples. Combining RF and MPC could be used to enhance the elastic behavior of dough from CF systems.Significance and NoveltyDeconvoluted DSC peaks provided insight into the multiple thermal transitions that occurred during the processing of CF‐based foods. The overall results from this study could help in the formulation of food containing rice−mung bean CF in excess water or in a dough system.

Pasting, Rheological, and Tribological Properties of Rice Starch and Oat Flour Mixtures at Different Proportions.

Rice starch (RS) and oat flour (OF) were mixed in different proportions, and the pasting properties, particle size, rheology, and tribological properties of the mixed system were analyzed. According to the RVA results, OF inhibited the starch pasting, and the pasting temperature and peak viscosity of the mixed system increased. The particle size shifted toward the small particle size after the mixing of RS and OF components, and the RS/OF 9/1 particle size is the smallest. All samples exhibited shear dilution behavior and the viscosity of the system could be significantly increased at a 10 wt% RS content. At sliding speeds of >1 mm/s, the friction of the mixture is usually between the two individual components, which also confirmed the association or interaction between the two polymers.

어닐링 처리후 제조한 옥테닐호박산 쌀전분의 물리적 및 유화 특성

Purpose: This study investigated the effect of annealing on the physical and emulsifying properties of octenyl succinate (OSA)-modified starches(3% OSA, pH 8.5, 6h). Methods: The physical, pasting properties, oil absorption capacity, thermal properties, crystallinity and emulsifying stability of OSA starch prepared after annealing from nonwaxy rice starch, called AnOSA, were analyzed. Results: Annealing treatment increased the water holding capacity, pasting temperature and pasting peak viscosity, but decreased the swelling power and solubility of OSA starch. The onset temperature(T_o) and peak temperature(T_p) of the AnOSA starches by differential scanning calorimetry (DSC) were increased, but the temperature range decreased due to annealing. The characteristics of native starch and OSA starches by X-ray diffractometry were not altered by annealing. The creaming index of emulsions with AnOSA starches was 0% after 21 days. Conclusion: The OSA starch prepared after annealing of nonwaxy rice starch can be utilized as a modified starch and emulsifier.

Variety difference in physico-chemical, cooking, textural, pasting and phytochemical properties of pigmented rice

Three different varieties of pigmented rice namely Chakhao Amuba (Black), Chakhao Angangba (Red), Chakhao Poreiton (Purple) and a non-pigmented Chakhao Angouba (White) rice grown in Manipur, India were investigated for their physicochemical, phytochemical, cooking, textural and pasting properties. Thousands kernel weight, bulk density and length/breadth ratio for all varieties varied in the range of 16.69 to 21.17g, 0.59 to 0.65g/mL and 2.87 to 3.25, respectively. All pigmented rice showed significant amount of total phenolic content, flavonoid content and antioxidant activities. Black rice showed the highest phenolic content (12.70 mg GAE/g), Red rice showed highest flavonoid content (6.12 mg catechin/g) and DPPH % inhibition (92.62 %). Highest anthocyanin content was observed in the black rice variety (9.13 mg Cyanidin-3-glucoside/g). Cooking time was found highest (31.33 min) in Purple rice which can be correlated with the amylose content. Maximum amylose content was recorded in purple rice (6.44g/100g). Water uptake ratio was found in the range of 2.03 to 2.71. Highest amylose content rice (Purple rice) has the highest hardness value (173.18 N) which is positively correlated with the amylose content. The colour values were reduced after cooking of rice which may be due to degradation in monomeric anthocyanins due to heat treatment. Red rice showed the highest pasting temperature, peak, hold and final viscosity compared to other rice varieties.

Relationships between X-ray Diffraction Peaks, Molecular Components, and Heat Properties of C-Type Starches from Different Sweet Potato Varieties.

C-type starches with different proportions of A- and B-type crystallinities have different intensities and crystallinities of X-ray diffraction peaks. In this study, the intensities and crystallinities of X-ray diffraction peaks, molecular components and heat properties of C-type starches were investigated in seven sweet potato varieties, and their relationships were analyzed. The intensity and crystallinity of a diffraction peak at 5.6° were significantly positively correlated to the DP6-12 branch-chains of amylopectin and significantly negatively correlated to the true amylose content (TAC) determined by concanavalin A precipitation, gelatinization temperature, gelatinization enthalpy, water solubility at 95 °C, and pasting temperature. The intensity of diffraction peaks at 15° and 23° were significantly positively correlated to the gelatinization temperature and pasting temperature and significantly negatively correlated to the pasting peak viscosity. The significantly positive relationships were detected between the crystallinity of a diffraction peak at 15° and the DP13-24 branch-chains of amylopectin, gelatinization conclusion temperature and water solubility, between the crystallinity of diffraction peak at 17–18° and the TAC, gelatinization onset temperature, water solubility and pasting temperature, between the crystallinity of a diffraction peak at 23° and the gelatinization conclusion temperature and pasting peak time, and between the total crystallinity and the TAC, gelatinization conclusion temperature, water solubility and pasting temperature. The score plot of principle component analysis showed that the molecular components and heat property parameters could differentiate the C-type starches and agreed with their characteristics of X-ray diffraction peaks. This study provides some references for the utilizations of C-type starches.

Mapping combined with principal component analysis identifies excellent lines with increased rice quality

Quality-related traits are some of the most important traits in rice, and screening and breeding rice lines with excellent quality are common ways for breeders to improve the quality of rice. In this study, we used 151 recombinant inbred lines (RILs) obtained by crossing the northern cultivated japonica rice variety ShenNong265 (SN265) with the southern indica rice variety LuHui99 (LH99) and simplified 18 common rice quality-related traits into 8 independent principal components (PCs) by principal component analysis (PCA). These PCs included peak and hot paste viscosity, chalky grain percentage and chalkiness degree, brown and milled rice recovery, width length rate, cooked taste score, head rice recovery, milled rice width, and cooked comprehensive score factors. Based on the weight ratio of each PC score, the RILs were classified into five types from excellent to poor, and five excellent lines were identified. Compared with SN265, these 5 lines showed better performance regarding the chalky grain percentage and chalkiness degree factor. Moreover, we performed QTL localization on the RIL population and identified 94 QTLs for quality-related traits that formed 6 QTL clusters. In future research, by combining these QTL mapping results, we will be using backcrossing to aggregate excellent traits and achieve quality improvement of SN265.