Peak Gelatinization Temperature Research Articles

Unlocking the Nutritional Potential of Australian Yam (Dioscorea spp.)

Yam (Dioscorea spp.), a staple food among Australia's First Nations people, has nutritional, cultural, and historical significance, connecting them to their land, identity, and well-being. However, information on the nutritional value and quality characteristics of the tubers and their main nutritional component (starch) are lacking in literature. This study investigates the nutritional composition of the flesh and peel from two yam species (D. alata (DaF and DaP) and D. bulbifera (DbF and DbP)), as well as the physicochemical properties of their starch, which can affect their food and non-food uses. The flesh and peel of the tested yam species had a high moisture content (high fresh weight), with starch being the main component in the flesh of both species (DaF-55.8%, DbF-68.9%). The peel and flesh are low in fat and protein, a good source of dietary fibre, with fructose, glucose and sucrose being the main sugars present. The flesh and peel are high in minerals (K, Ca, Na and P), trace (Cu) and ultra-trace elements (Rb, B), as well as essential amino acids. The starch peak gelatinization (Da-78.0 and Db-78.1°C) and pasting temperature (Da-84.0 and Db-84.1°C) in both species were relatively high, with the D. alata peak viscosity (8000cp) significantly (p <0.05) higher than that of D. bulbifera (7701cp). This study affirms First Nations Peoples traditional knowledge of yams’ nutritional value, highlighting their potential for integration into the Australian ‘mainstream’ diet. Promoting indigenous foods is also a successful strategy to develop environmentally friendly and sustainable supply chains.

Rheological, Thermal and Physicochemical Properties of Bioprocessed Flour From Cowpea, Sorghum and Orange Fleshed Sweet Potato

ABSTRACTThis study investigated the rheological, physicochemical, and thermal properties of fermented and germinated whole reddish‐brown cowpea, white sorghum and orange‐fleshed sweet potato. Germination substantially reduced the pasting and rheological attributes of flour suspensions compared to the fermentation process. This study observed notable increases in the hot paste, setback, and final viscosities after the fermentation of cowpea and sorghum, indicating an improvement in the ease of cooking and greater retrogradation tendency of starch molecules. Among the fermented flours, sorghum had the highest hot paste viscosity (848 mPa s) and final viscosity (1451 mPa s). The mechanical fingerprint revealed a viscoelastic solid character, with G′ &gt; G″ over the frequency range of 0–10 rad/s for all samples. Temperature sweep data showed a sharp increase in G′ at about 80°C, corresponding to the onset of starch gelatinization. Shear‐thinning behavior was observed, except in germinated and raw sorghum flours, where molecular rearrangement resulted in an initial viscosity rise at a low share rate (&lt; 20 s−1). Differential scanning calorimetric analysis revealed a marginal variation in the peak transition temperature of gelatinization (98°C–104°C for all flours except raw sorghum flour, 83.87°C). The fermented sweet potato flour indicated good flour particle flowability expressed as Carr's compressibility index (30.99) and the Hausner ratio (1.45); however, the available reducing sugars could have influenced its high percentage solubility (49.83%), thus impacting low pasting viscosities. The contrasting technological features suggest an avenue to intensify efforts in exploring composite bioprocessed flours for applications in novel foods.

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

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

Assessing the occurrence of barley starch annealing under heat, moisture and time conditions relevant for kilning: An experimental design approach

In this work, the possible occurrence of barley starch annealing under kilning conditions was investigated. Using an I-optimal response surface methodology, the impact of temperature (45–55 °C), moisture content (30–50%) and time (1–5h) on the gelatinisation behaviour of starch in green malt was studied. An increase in onset (0.5–4.3 °C) and peak temperature (0.5–2.7 °C) and a change in peak width (+0.5 to - 3.2 °C) of the starch gelatinisation endotherm showed the extent of annealing that occurred within an industrially relevant design space. Temperature was the main driver behind the observed changes, but also interaction effects between temperature, moisture content and time contributed. Combined with increasingly high starch gelatinisation temperatures in barley, the observed increases in peak gelatinisation temperature due to annealing could hamper fermentable sugar production during brewing.

Effects of additives (NaCl, citric acid, and ethanol) on the cooking quality and sensory quality of vermicelli produced from freeze–thaw‐dehydrated whole potato powder

SummaryTo conform to the trend of whole‐food diets in recent years, whole potato powder has been used for the processing of extruded vermicelli. The effects of different additives, such as NaCl, citric acid and ethanol, on the cooking quality and sensory quality of whole potato vermicelli obtained via twin‐screw extrusion were investigated. The colour, gelatinisation properties, water absorption, cooking loss, texture profile analysis, scanning electron microscopy analysis and correlation analysis of the whole potato vermicelli were determined and discussed. The brightness of the whole potato vermicelli increased from 52.0 to 55.4 at 1% NaCl addition and increased from 52.0 to 54.9 at 0.8% citric acid addition, and the water absorption of the whole potato vermicelli increased from 83.1% to 159.1% at 0.4% citric acid addition and increased from 83.1% to 258.9% at 8% ethanol addition. The cooking loss of the whole potato vermicelli decreased from 5.3% to 5.1% at 8% ethanol addition, indicating that ethanol could improve the cooking quality of whole potato vermicelli. The texture properties of the whole potato vermicelli decreased with the addition of ethanol, and the ΔH of the whole potato vermicelli decreased from 3.7 to 1.8 J g−1 at 0.8% citric acid addition and decreased from 3.7 to 1.5 J g−1 at 8% ethanol addition, respectively. Moreover, the addition of ethanol was negatively correlated with the max force, break distance, stretching work, hardness, adhesiveness and chewiness of the whole potato vermicelli. The addition of NaCl was positively correlated with the peak gelatinisation temperature. All three additives affected the microstructure of the whole potato vermicelli, including roughening the cross section and increasing the number of pores. In this study, NaCl improved the gelatinisation properties of whole potato vermicelli, citric acid and ethanol improved the water absorption of the whole potato vermicelli, and citric acid improved the anti‐browning effects of the whole potato vermicelli.

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

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

Physicochemical characteristics of tea seed starches from twenty-five cultivars

The physicochemical features of starches separated from tea seeds of 25 cultivars were analyzed. The distinct characteristic of tea seed starches was that they had high apparent amylose content (AAC, 28.94–39.91 %) and resistant starch contents (4.64–8.24 %), suggesting that tea starch can be used for production of low glycemic index food. One cultivar (T12) had smallest breakdown (74.2 RVU) and highest gel hardness, indicating it performed stably during shear thinning, resulting in a firm texture. Another cultivar (T25) had a peak viscosity of 417.6 RVU, a large breakdown and small setback, suggesting a low tendency for retrogradation. There was a range of 61.6 °C to 77.5 °C for the peak gelatinization temperature and 0.163 to 0.390 for the flow behavior index values. These parameters could serve for selecting suitable starches with minor differences in physicochemical properties for food use. Correlation analysis indicated that AAC is a key factor determining starch retrogradation properties. The broad genetic diversity in the tea seed starch physicochemical features provided potentially versatile applications in the food industry. The results gained from the present study contribute to a better understanding of tea seed starch quality, and encourage its application in many value-added food products.

A global set of barley varieties shows a high diversity in starch structural properties and related gelatinisation characteristics

The gelatinisation temperature and bimodal granule size distribution of barley starch are important characteristics regarding resource efficiency and product quality in the brewing industry. In this work, the diversity in starch amylose content and granule proportions in a set of modern barley varieties (N = 23) was investigated and correlated with their starch gelatinisation behaviour. Milled barley samples had peak starch gelatinisation temperatures ranging from 60.1 to 66.5 °C. Upon separating the barley starch from the non-starch compounds, sample-dependent decreases in starch gelatinisation temperatures were observed, indicating the importance of differences in barley composition. The peak gelatinisation temperatures of milled barley and isolated barley starches were strongly correlated (r = 0.96), indicating that the behaviour of the starch population is strongly reflected in the measurements performed on milled barley. Therefore, we investigated whether amylose content or starch granule size distribution could predict the gelatinisation behaviour of the starches. Broad ranges in the small starch granule volumes (13.9–32.0 v/v%) and amylose contents (18.2–30.7 w/w%) of the barley starches were observed. For the barley samples collected in the north of the USA (N = 8), the small starch granule volumes correlated positively with the peak gelatinisation temperatures of barley starches (r = 0.90, p < 0.01). The considerable variation in starch properties described in this work highlights that, besides starch content, starch gelatinisation temperature or granule size distribution might provide brewers with useful information to optimise resource efficiency.

Effect of Intermittent Low-Pressure Radiofrequency Helium Cold Plasma Treatments on Rice Gelatinization, Fatty Acid, and Hygroscopicity.

To establish the safe and reproducible effects of cold plasma (CP) technology on food products, this study evaluated the gelatinization parameters, fatty acid profile, and hygroscopic properties of rice grains repeatedly treated with low-pressure radiofrequency (RF) helium CP (13.56 MHz, 140 Pa, 120 W-20s, 0-4 times, and 300 g sample). Compared with the untreated (zero times) sample, with an increase in CP treatment times from one to four on rice, the water contact angle and cooking time decreased, while the water absorption rate and freshness index increased, and the pH value remained unchanged. CP repeating treatments essentially had no effect on the gelatinization enthalpy, but significantly increased the peak temperature of gelatinization. From the pasting profile of rice that has been repeatedly CP treated, the peak, breakdown, and setback viscosities in flour paste decreased. CP repeating treatments on rice did not change the short-range molecular order of starch. Compared with the untreated sample, the first helium CP treatment maintained the content of C18:1n9c, C18:2n6c, and C18:3n3, but the second to fourth CP treatment significantly decreased contents of these fatty acids (FAs) as the C18:0 content increased. The first three CP treatments can increase the water and sucrose solvent retention capacity in rice flours. CP repeatedly treated rice first exhibits the similar monolayer water content and solid surface area of water sorption. Principal component analysis shows that contact angle, pasting parameters, and fatty acid profile in milled rice are quite sensitive to CP treatment. Results support that the effect of low-pressure RF 120W helium CP treatment 20 s on rice grains is perdurable, and the improvement of CP intermittent treatments on rice cooking and pasting properties is an added benefit, and the hygroscopic properties of rice was kept.

Population Structure and Genetic Diversity of Shanlan Landrace Rice for GWAS of Cooking and Eating Quality Traits.

The Shanlan landrace rice in Hainan Province, China, is a unique upland rice germplasm that holds significant value as a genetic resource for rice breeding. However, its genetic diversity and its usefulness in rice breeding have not been fully explored. In this study, a total of eighty-four Shanlan rice, three typical japonica rice cultivars, and three typical indica rice cultivars were subjected to resequencing of their genomes. As a result, 11.2 million high-quality single nucleotide polymorphisms (SNPs) and 1.6 million insertion/deletions (InDels) were detected. Population structure analysis showed all the rice accessions could be divided into three main groups, i.e., Geng/japonica 1 (GJ1), GJ2, and Xian/indica (XI). However, the GJ1 group only had seven accessions including three typical japonica cultivars, indicating that most Shanlan landrace rice are different from the modern japonica rice. Principal component analysis (PCA) showed that the first three principal components explained 60.7% of the genetic variation. Wide genetic diversity in starch physicochemical parameters, such as apparent amylose content (AAC), pasting viscosity, texture properties, thermal properties, and retrogradation representing the cooking and eating quality was also revealed among all accessions. The genome-wide association study (GWAS) for these traits was conducted and identified 32 marker trait associations in the entire population. Notably, the well-known gene Waxy (Wx) was identified for AAC, breakdown viscosity, and gumminess of the gel texture, and SSIIa was identified for percentage of retrogradation and peak gelatinization temperature. Upon further analysis of nucleotide diversity in Wx, six different alleles, wx, Wxa, Wxb, Wxin, Wxla/mw, and Wxlv in Shanlan landrace rice were identified, indicating rich gene resources in Shanlan rice for quality rice breeding. These findings are expected to contribute to the development of new rice with premium quality.

Comparative Evaluation of the Physico-Chemical Characterization of Native and Modified Starches from Jackfruit, Corn and Cassava as Potential Additives in Drilling Fluid

The physicochemical properties of starches determine their industrial application, and modification have shown further improvement on the properties of starch. Hence, the physicochemical properties of modified starches obtained from jackfruit were analyzed and compared with native jackfruit (JF), corn (MN) and cassava (CN) starches to determine their usability as additives in drilling fluid formulation. Starch from jackfruit pulp was chemically modified with two carboxymethylation methods (JC1 &amp; JC2) and acetylation method (JA). The physicochemical properties were assessed using Scanning Electron Microscopy, Differential Scanning Calorimetry, Fourier transform infrared spectroscopy and Thermogravimetric analysis to determine their effectiveness to improve JF properties. The results revealed that at 90 °C, JC2 was found to have the highest swelling power and water holding capacity when compared with other modified and native starches. The result of the thermal properties of the starches showed that JC2 produced better thermal properties with the peak gelatinization temperature in the decreasing trend JC2&gt;JC1&gt;JF&gt;MN&gt;JA&gt;CN. The SEM result showed that modification reduced the particle size of the starches thereby increasing the surface area of the starches for better reactivity than the native jackfruit, corn and cassava starches. The thermal stability of the starches showed that modification by carboxymethylation (JC1 and JC2) improved the stability of the starches while the reverse was the case for JA. In comparison with corn and cassava, the modified starches JC1 and JC2, performed excellently in all the properties analyzed. The possession of the highest swelling power, highest water holding capacity, highest thermal stability and excellent gelatinization temperature of 90 ℃ (Tp) places JC2 above other modification methods thereby making it a potential replacement for corn and cassava as an additive in drilling fluid formulation.

Interactions and functionality of fiber components in a directly expanded starch matrix

The interactions of cellulose (2–10%), hemicellulose (1–5%), pectin (1–5%), lignin (1–5%) and a blend of these fibers (5–25%) with cornstarch matrix were studied and the effect of these fibers on properties of cellular extrudates determined. Peak gelatinization temperature increased from 94.3 °C for the starch control to 96.6–103.1 °C with addition of fibers. Extrusion specific mechanical energy decreased on addition of fibers (338 kJ/kg versus 197–308 kJ/kg) with the largest decrease observed for cellulose. Longitudinal expansion increased with addition of fibers (specific length 35 mm/g versus 62–67 mm/g). Addition of pectin led to higher radial expansion (23 versus 24–27), while cellulose caused a decrease (14–23). Microstructure features evaluated using X-ray microtomography were similar for the control and pectin regarding cell size and void fraction, while cellulose caused a different microstructure (2249 μm and 83.7%, respectively, for control; 2334 μm and 89.0% for 5% pectin; 473.3 μm and 72.1% for 10% cellulose). Crushing force was inversely related to cell size. It was concluded that impact of fibers on cellular extrudates was related to compatibility with starch.

Thermal Properties and Dynamic Rheological Characterization of Dioscorea Starch Gels.

Yam (Dioscorea. sp.) is an edible starchy tuber with potential for being a commercial source of starch for industrial purposes, but yam starch is underutilized. The dynamic oscillatory and thermal properties of yam starches from sixteen varieties each of Dioscorea. rotundata, Dioscora. alata, Dioscorea. bulbifera and one variety of Dioscorea. dumetorum from Nigeria were studied to determine their potential for industrial utilization. The storage modulus, loss modulus, damping factor and complex viscosity as a function of frequency (ω) of the dioscorea gels, as well as the onset temperature (To), peak gelatinization temperature (Tp), end of gelatinization (TC), and gelatinization enthalpy of the starches were determined by standard procedures. Results showed that all the dioscorea starches showed a typical elastic behavior with the magnitude of G' greater than G″ while tan δ < 1 in all varieties. Thus, the starch gels were more elastic than viscous. All the starch gels exhibited shear thinning characteristics and showed frequency (ω) independence characteristics of weak gels. D. rotundata varieties had the lowest ∆Hgel, while D. bulbifera varieties had the highest. The diversity of the visco-elastic and thermal properties of the yam starch gels from different varieties and species can be an advantage in their utilization in both food and non-food industries.

Morphological, textural analysis and freeze-thaw stability of starches from legume grow in Cameroon.

Starches from some legume grown in Cameroon were evaluated for their granule structure and size, turbidity, firmness and gel strength, thermal and freeze-thaw properties. Amylose contents were in the range of 26.21%-44.85%. Morphological analysis of the starch granules showed bimodal distribution, multiple sizes and shapes from small spherical to the bigger kidney shape. Significant differences were observed among starch in light transmittance, firmness and gel strength. The thermal parameters of starches were evaluated using differential scanning calorimeter and significant differences were observed. The peak gelatinisation temperature was positively correlated to starch granule size but the amylose content showed no evidence of their impact on legume starch properties studied. The data reported can be useful to facilitate the selection of variety of legume and conditions closer to the desired application.

Preparation and characterization of fine and stable short amylose nanocarriers for curcumin using a highly efficient and convenient method

To prepare fine and stable nanocarriers for curcumin using a highly efficient and convenient method, nanoprecipitation combined with ultrasonication and a high-speed dispersion (US+HSS) method were used to prepare short amylose nanoparticles with pre-formed helical structures. Their morphology, structural characteristics, and embedding effects for curcumin were investigated. The results showed that the optimal ratio of ethanol to short amylose solution and ultrasonic time was 4:1 and 4 min, respectively. The nanoparticles showed a small size (82.43 nm), relatively high loading capacity (11.57 %), and a peak gelatinization temperature of 97.74 °C. Compared to the nanoprecipitation method, the short amylose nanoparticles prepared using the US+HSS method possessed a higher V-type crystalline structure ratio. In addition, the US+HSS method was easier to use to prepare nanoparticles with high stability against NaCl, and the stable nanoparticles showed the best in vitro sustained release effect for curcumin. The Peppas–Sahlin model was the optimal model that matched curcumin release from nanoparticles during digestion.

Heat-moisture treated waxy highland barley starch: Roles of starch granule-associated surface lipids, temperature and moisture

Roles of temperature, moisture and starch granule-associated surface lipids (SGASL) during heat-moisture treatment (HMT) of waxy highland barley starch were elucidated. Starch without SGASL showed a higher increase in ratio (1016/993 cm−1) (0.095–0.121), lamellar peak area (88), radius of gyration (Rg1, 0.9–1.8 nm) and power-law exponents (0.19–0.42) than native starch (0.038–0.047, 46, 0.1–0.6 nm, 0.04–0.14), upon the same increase in moisture or temperature. Thus, removing SGASL promoted HMT. However, after HMT (30 % moisture, 120 °C), native starch showed lower relative crystallinity (RC, 11.67 %) and lamellar peak area (165.0), longer lamellar long period (L, 14.99 nm), and higher increase in peak gelatinization temperature (9.2–13.3 °C) than starch without SGASL (12.04 %, 399.2, 14.52 nm, 4.7–6.1 °C). This suggested that the resulting SGASL-amylopectin interaction further destroyed starch structure. Starch with and without SGASL showed similar trends in RC, lamellar peak area, L and Rg1 with increasing temperature, but different trends with increasing moisture, suggesting that removing SGASL led to more responsiveness to the effects of increasing moisture. Removing SGASL resulted in similar trends (RC and lamellar peak area) with increasing moisture and temperature, suggesting that the presence of SGASL induced different effects on moisture and temperature.

Impact of moisture content on microstructural, thermal, and techno-functional characteristics of extruded whole-grain-based breakfast cereal enriched with Indian horse chestnut flour

The use of non-conventional seed flour is of interest in obtaining healthy breakfast cereals. The research aimed to study the physico-functional, bioactive, microstructure, and thermal characteristics of breakfast cereals using scanning electron microscopy, X-ray diffractometry, and differential scanning calorimeter. The increase in feed moisture content (16 %) enhanced the bulk density (5.24 g/mL), water absorption index (7.76 g/g), total phenolic content (9.03 mg GAE/g), and antioxidant activity (30.36 %) having desirable expansion rate (2.84 mm), water solubility index (48 %), and color attributes. The microstructure showed dense inner structures with closed air cells in extruded flours.Extrusion treatment rearranged the crystalline structure from A-type to V-type by disrupting the granular structure of starch, reducing its crystallinity, and promoting the formation of an amylose–lipid complex network. Increasing conditioning moisture enhanced the degree of gelatinization (%), peak gelatinization temperature (Tp), and starch crystallinity (%) and reduced the gelatinization enthalpy (ΔHG) and gelatinization temperature ranges. The results reported in this study will help industries to develop innovative and novel food products containing functional ingredients.

Insight into the improvement in pasting and gel properties of waxy corn starch by critical melting treatments

To improve the pasting and gel properties of waxy corn starch (WCS), the native starch was modified by critical melting (CM) at the onset temperature (TO), peak temperature (TP), and conclusion temperature (TC) (labeled CMO, CMP, and CMC respectively). CM treatments significantly enhanced the thermal stability of the WCS, as indicated by the increase in the peak gelatinization temperature, pasting temperature, and peak time. In addition, after CMP treatment, the storage modulus, hardness, gumminess, springiness, and chewiness of starch gels significantly increased by 43.29 %, 31.14 %, 23.36 %, 8.26 %, and 61.43 %, respectively, and the syneresis rate significantly decreased by 19.69 % (p < 0.05). These results indicated that CMP treatments significantly improved the gelling ability and freeze-thaw stability of the WCS. These results are ascribed to the partial disruption and enhanced rearrangement of the starch crystalline structure. CMP treatment induced the crystalline structure of starch to be partially disrupted and a hard structure was formed on the surface of starch granules. The hard structure in CMP-treated starch supplied more attachment points for crystalline structure rearrangement during gelatinization. Therefore, the above results indicated that CMP treatments can be used to modify starch to improve the pasting and gel properties of starch-based food products.

Assessment of freeze damage in tuber starch with electrical impedance spectroscopy and thermodynamic, rheological, spectrographic techniques

In this study, we aimed to use electrical impedance spectroscopy (EIS) to assess the freeze-damage level of starches from potato tubers treated with multiple freezing-thawing (FT) cycles. The results showed that the relationship between the physicochemical properties of starches and the impedance characteristics of starch paste is temperature-dependent. As the temperature rises to 70–90 °C, the impedance modules show a significant correlation with the amylose and mineral contents, gelatinization and pasting properties, short-range ordered structure, relative crystallinity, and damage level within the range of 10–1 MHz (p < 0.01). This could be because FT leads to a reduction in amylose and ion content. Compared to a high level of freeze-damaged starch (FDS), a low level of FDS has less amylopectin and more amylose. Additionally, the ions could be typically evenly distributed throughout the unbranched linear amylose structure in starch paste. At the peak gelatinization temperature, the starch paste made from a low level of FDS exhibits a weakened network structure, allowing more unbound water for ion movement and enhancing electric conduction. In conclusion, EIS can predict the damage level and properties of FDS, which can benefit the frozen starchy food industry.

Characterization of different high amylose starch granules. Part I: Multi-scale structures and relationships to thermal properties

The multi-scale structure and thermal properties of eight widely different types of high-amylose starches (HASs) having amylose contents (AC) in the range of 34.4%–97.3% originating from maize, wheat, barley, and potato were analyzed to unveil possible relationships among different levels of structures and thermal properties. The starches were found to cluster in four groups: (I) two HASs from maize, Gelose50 and Gelose80, with high gelatinization enthalpy (△H) and low onset (T0) and peak (Tp) gelatinization temperatures, (II) two HASs from potato and wheat, with medium and high △H and extremely low T0 and Tp, (III) two HASs from maize, NAFU50 and NAFU60, with medium △H and medium T0 and Tp, (IV) two HASs from maize and barley, Hylon VII and AOBS, with low △H but high T0 and Tp. The degree of molecular branching and the extent of the granule V-type crystalline polymorph were the critical factors determining their thermal properties, while botanical source and AC were not found important. HASs from wheat and barley showed relatively low lamellar and crystalline order, which was related to high content of amylopectin or AM-like chains with degree of polymerization (DP) 6–12 and long amylose chains, both of which can contribute to prevent the formation of double helices. Our data pinpoint the importance of amylopectin short chains, amylose long chains, and degree of branching on HAS starch granule structural order and thermal stability, which are potentially useful in boosting the development of HAS-based products and be beneficial for developing new HAS crops.