Search Results (26)

Sweet potato (Ipomoea batatas (L.) Lam.; SP) flour enhances food nutrition and bioactivity while functioning as a thickening/gelling agent. This study investigated the impact of two drying methods [hot-air (75 °C/20 h) and freeze-drying (−41–30 °C/70 h)] on the physical–functional properties of flours from three SP varieties: Bonita (white-fleshed), Bellevue (orange-fleshed), and NP1648 (purple-fleshed). Particle size, morphology, water/oil absorption capacities (WAC/OAC), bulk density, swelling power (SwP), water solubility (WS), foaming/emulsifying properties, least gelation concentration (LGC), and gelatinisation temperature (GT) were analysed. Both the drying method and variety significantly influenced these properties. Hot-air-dried flours exhibited bimodal particle distribution, compact microstructure, and aggregated starch granules, yielding higher WAC (≈3.2 g/g) and SwP (≈3.6 g/g). Freeze-dried flours displayed smaller particles, porous microstructure, and fragmented granules, enhancing OAC (≈3.0 g/g) and foaming capacity (≈17.6%). GT was mainly variety-dependent, increasing as Bellevue (74.3 °C) < NP1648 (78.5 °C) < Bonita (82.8 °C), all exceeding commercial potato starch (68.7 °C). NP1648 required lower LGC (10% vs. 16% for others). All flours exhibited high WS (24–39.5%) and emulsifying capacity (≈44%). These results underscore the importance of selecting the appropriate drying method and variety to optimise SP flour functionality for targeted food applications. Freeze-dried flours might suit aerated/oil-retentive products, while hot-air-dried flours could be ideal for moisture-sensitive formulations. Full article

Abscisic acid (ABA) plays an important regulatory role in the grain filling process, which in turn will affect the final yield and quality of rice. The ABA biosynthesis genes of OsNCED3 and degradation gene OsABA8ox3 affect the ABA content, and then further regulate the ABA signaling. During the development of rice panicle, compared with primary grains (superior grains) growing on primary branches, secondary grains (inferior grains) growing on secondary branches exhibit characteristics. However, little is reported on the physicochemical characteristics of starch between superior and inferior grains in ABA related transgenic lines. In this study, OsNCED3 and OsABA8ox3 transgenic plants were used as materials. The results showed that compared with the WT, the OsNCED3-RNAi lines on grain weight was consistent with the trend of superior and inferior grains, while the OsABA8ox3-RNAi lines affected superior or inferior grains. The total starch and soluble sugar content of grains decreased in both OsNCED3-RNAi and OsABA8ox3-RNAi lines, and the total starch content of superior and inferior grains in OsABA8ox3-RNAi lines decreased. The starch granule size distribution of all samples showed a bimodal and increased proportion of starch grains with large granule size, in which the influence on inferior grains was greater than that of superior grains, which eventually led to a significant increase in their average granule size. The apparent amylose content of inferior grains increased significantly in most lines. The swelling power of the superior grains decreased significantly, while that of the inferior grains increased significantly. Fourier analysis showed that the order degree of starch granule surface decreased in the superior grains of the RNAi line, while it increased in the inferior grains of the OsABA8ox3-RNAi line but decreased in the OsNCED3-RNAi lines. In the superior grains, the relative crystallinity of starch decreased in the OsNCED3-RNAi lines, but remained unchanged or increased in the OsABA8ox3-RNAi line. In inferior grains, the relative crystallinity of starch decreased in the ABA synthesis RNAi line, but increased in the OsABA8ox3-RNAi line. In summary, the influence of ABA on the physicochemical properties of inferior grains is greater than that of superior grains. Full article

The structure and physicochemical properties of starch were important factors to determine the quality of foxtail millet. While hybrid foxtail millet has made greater progress in yield, it has made slower progress in quality than conventional foxtail millet with a more complex genetic base, which was jointly influenced by the parents. However, there were no reports on the comparison of the starch structure and physicochemical properties of hybrid foxtail millets and their parents. In this study, the amylose content, morphology structure, granule size distribution, X-ray diffraction, short-range ordered structure, pasting properties, and thermal characteristics of starches derived from Changzagu 466 (466), Changzagu 333 (333), Changzagu 2922 (2922) and their parent materials were analyzed. The results showed that compared with male parents, the starches from three hybrid foxtail millets and their female parents had larger average particle size, d(0.1), d(0.5), and gelatinization enthalpy (ΔH), while the amylose content values of three hybrid foxtail millets were 26.0%, 28.8%, and 28.9%, which were between the parents (25.8~27.1%, 25.4~28.8%, and 23.6~29.5%), with conclusion temperature (Tc) being higher than the parents and having a lower breakdown viscosity. The peak viscosity of Changzagu 466 (466) and Changzagu 2922 (2922) was 5235.5 cP and 5190.8 cP, respectively, lower than that of their parents (5321.0~6006.0 cP and 5257.0~5580.7 cP), while the peak viscosity of Changzagu 333 (333) was 5473.8 cP, falling between the parental values (5337.5~5639.5 cP). The cluster analysis results showed that the starch structure and physicochemical properties of hybrid foxtail millet were significantly different from those of female parents, which were mainly influenced by male parents. The findings of this study will establish a theoretical foundation for the enhancement and innovation of high-quality foxtail millet germplasm resources, as well as the development of high-quality hybrid foxtail millet combinations. Full article

During retail storage, potato tubers are exposed to light that results in tuber greening. Green tubers are toxic and rejected by consumers. In the present study, the effect of Citrashine^® natural wax on the postharvest tuber greening of two potato cultivars (‘Mondial’ and ‘Sifra’) was studied. The tubers were irradiated with white light during a 12-day storage period at ambient temperature. During light exposure, tubers were evaluated for colour, pigmentation, chlorophyll fluorescence and starch granule distribution at 3-day intervals. The results showed that wax-treated tubers had significantly (p < 0.05) less green colour as represented by visual and objective colour parameters (a*, b*, C* and h°), compared to those treated with water (control). The pigmentation of the tubers was significantly influenced by the postharvest Citrashine^® natural wax treatment. The total chlorophyll content was significantly lower in wax-treated tubers, while the carotenoid content was significantly higher in wax-treated tubers compared to their contents in control samples. Scanning electron microscopy showed that the starch granule size was normally distributed in wax-treated tubers compared to the untreated ones, which was negatively skewed. In conclusion, Citrashine^® natural wax showed the potential to be a postharvest technology for controlling greening defects on potato tubers. The results provide a possible effective strategy for controlling the postharvest greening of potato tubers. Full article

Starch nanocrystals (SNCs) to stabilize high internal phase emulsions (HIPEs) always suffer low production efficiency from acid hydrolysis. Due to its small granule size, Quinoa starch (QS) was selected to produce SNCs as a function of acid hydrolysis time (0–4 days), and their structural changes and potential application as HIPEs’ stabilizers were further explored. With increasing the acid hydrolysis time from 1 day to 4 days, the yield of QS nanocrystals decreased from 30.4% to 10.8%, with the corresponding degree of hydrolysis increasing from 51.2% to 87.8%. The occurrence of QS nanocrystals was evidenced from the Tyndall effect and scanning electron microscopy with particle size distribution. The relative crystallinity of QS subjected to different hydrolysis times (0–4 days) increased from 22.27% to 26.18%. When the acid hydrolysis time of QS was 3 and 4 days, their HIPEs showed self-standing after inversion, known as high internal phase emulsion gels (HIPE gels), closely related to their densely packed interfacial architecture around oil droplets, seen on an optical microscope, and relatively high apparent viscosity. This study could provide a theoretical guidance for the efficient production and novel emulsification of SNCs from QS to HIPE gels. Full article

Granule size distribution of wheat starch is an important characteristic that could affect the functionality of wheat (Triticum aestivum L.) products. Lodging is a major limiting factor for wheat production. Few studies have been conducted to clarify how lodging influences the granule size distribution and viscosity parameters of starch in wheat grains. Two growing seasons, two high-yield winter wheat cultivars, and five artificial lodging treatments were imposed. The results indicated that lodging significantly reduced the content of starch and increased that of protein. Additionally, lodging caused a marked drop in both starch and protein yields. The relative loss of grain yield, starch yield, harvest index, and protein yield all differed remarkably among lodging treatments with a ranking of L2 > L1 > L4 > L3. Lodging also led to a reduction in the proportion (both by volume and by surface area) of B-type granules and a corresponding increase in that of A-type granules, and the more serious the lodging degree, the greater effect on the changes in these proportions. The smaller starch granules predominated in number, even though their collective contribution to the overall volume is was relatively minor. Meanwhile, it was found that the peak viscosity, hold viscosity, final viscosity, breakdown viscosity, and rebound value of wheat starch were significantly decreased by lodging. Correlation analysis showed that the peak and final viscosities were negatively correlated with volume percentages of A-type starch granules, but were positively correlated with B-type granules. This indicates that B-type granules have higher peak and final viscosities compared with A-type granules in wheat kernels. Lodging can reduce the proportion of B-type starch granules, and thus reduce the peak and the final viscosity in wheat grain. Full article

The objective of this study was to investigate granule size and distribution and deformability of granules and their effect on the rheological properties of waxy starch gels. Native (granular) waxy rice gels (10%) were prepared, and their response in oscillatory shear was investigated in the linear and non-linear viscoelastic regime. The results show the gels were mainly composed of aggregated and deformed swollen granules. Significance of granule size and its distribution, deformability of granules, and the molecular characteristics of amylopectin (AP) on storage modulus of those gels was demonstrated. A low degree of deformability of granules, typical for small granules with a broad size distribution and small molecular size of AP with short external chains, resulted in rigid and brittle gels. Highly deformed granules and high AP leachates, however, yielded soft gels. It was found that the transition of elastic to plastic behavior in the non-linear regime (LAOS) was gradual when AP had long external chains, but an abrupt transition was observed with the gel with short exterior chains of AP. Differences in rheological properties of cohesive waxy starch gels appear to be mainly impacted by the varying degrees of granule deformability and rigidity, which is further attributed to a combination of factors, including granule size, particle size distribution, molecular size, the external chain length of amylopectin (AP), and lipid content. The significance of this study is that it will assist the food industry in selecting suitable waxy rice starches to gain desired textural properties of end products. Full article

Biocomposites were fabricated utilizing polylactic acid (PLA) combined with native starch sourced from mountain’s yam (Dioscorea remotiflora Knuth), an underexplored tuber variety. Different starch compositions (7.5, 15.0, 22.5, and 30.0 wt.%) were blended with PLA in a batch mixer at 160 °C to produce PLA/starch biocomposites. The biocomposites were characterized by analyzing their morphology, particle size distribution, thermal, X-ray diffraction (XDR), mechanical, and dynamic mechanical (DMA) properties, water absorption behavior, and color. The results showed that the amylose content of Dioscorea remotiflora starch was 48.43 ± 1.4%, which corresponds to a high-amylose starch (>30% of amylose). Particle size analysis showed large z-average particle diameters (D_z0) of the starch granules (30.59 ± 3.44 μm). Scanning electron microscopy (SEM) images showed oval-shaped granules evenly distributed throughout the structure of the biocomposite, without observable agglomeration or damage to its structure. XDR and DMA analyses revealed an increase in the crystallinity of the biocomposites as the proportion of the starch increased. The tensile modulus (E) underwent a reduction, whereas the flexural modulus (E_flex) increased with the amount of starch incorporated. The biocomposites with the highest E_flex were those with a starch content of 22.5 wt.%, which increased by 8.7% compared to the neat PLA. The water absorption of the biocomposites demonstrated a higher uptake capacity as the starch content increased. The rate of water absorption in the biocomposites followed the principles of Fick’s Law. The novelty of this work lies in its offering an alternative for the use of high-amylose mountain’s yam starch to produce low-cost bioplastics for different applications. Full article

Germination is a natural, simple, and economical process used to improve the quality of nutritional and technological grains. In this study, native and sprouted sorghum flours were characterized regarding their technological properties (particle size distribution, water, and oil absorption capacity, swelling power and solubility, microscopy of starch granules, and pasting and thermal properties). Nutritional and phytochemical characterization profiles, including free sugars, fatty acids, organic acids, tocopherols, and phenolic compounds, were explored through chromatographic methods. The antioxidant, anti-inflammatory, and cytotoxic activities of the respective hydroethanolic extracts were also evaluated. The results showed that the germination process caused significant changes in the flour composition and properties, causing reduced gelatinization temperature and retarded starch retrogradation; an increased content of free sugars and total organic acids; and a decreased content of tocopherols and phenolic compounds. In terms of bioactivity, the sprouted sorghum flour extract showed better lipid-peroxidation-inhibition capacity and none of the extracts revealed hepatotoxicity or nephrotoxicity, which are important results for the validation of the use of the flours for food purposes. Germination is an efficient and alternative method for grain modification that gives improved technological properties without chemical modification or genetic engineering. Full article

Dumplings are a traditional Chinese food welcomed by Chinese people. Research has indicated that process of quick-frozen wheat cultivars and their gliadins are all related to the quality and shelf-life of dumplings. Therefore, the effect of freeze–thaw cycles on the textural properties and microscopic characteristics of two types of quick-frozen dumpling wrappers (Zhaomai and Wenmai 19) and conformation of their gliadins were investigated. Scanning electron microscopy showed that Wenmai 19 dumpling wrappers had apparent damage after the first cycle, but Zhaomai wrappers did not reveal significant changes until the fourth cycle. The particle size distribution in the starch granules of Wenmai 19 wrappers varied in terms of mechanical damage, but Zhaomai delayed or avoided such effects. FT-IR found a loose protein structure of the gliadins. Differential scanning calorimetry showed that gliadins of Wenmai 19 degenerated more than those of Zhaomai. The crosslinking of gliadin and glutenin maintained a high-quality gluten network, thus protecting the gliadin stability from ice crystals. In turn, the gliadin maintained the strength of the gluten network. Therefore, raw flours with high-quality protein networks are more suitable for frozen dumplings. Freeze–thaw cycles dramatically decreased the textural characteristics of dumpling wrappers and the microscopic characteristics of their gliadin proteins. Concerning wheat cultivars with weak gluten, flours with high-quality protein networks are more suitable as raw materials for frozen dumplings. Full article

Biomimetic foods are expected to have potential health benefits for the management and prevention of chronic diseases, such as diabetes and cardiovascular disease. In the current research, two commercially available and affordable plant proteins (soy protein isolate—SPI and pea protein isolate—PPI) at two levels (5%, 10%) were added to the Yangyu jiaotuan with the objective of developing a product with reduced glycaemic properties and high protein content while maintaining its original taste and texture. The results showed that several important textural properties such as hardness and chewiness did not change significantly during the refrigerated storage. The storage modulus G′ increased with refrigerated storage time for different samples, but there were significant differences among the five samples (with and without protein addition) with respect to frequency dependence during rheological measurements. The in vitro starch digestion experiments showed that the starch hydrolysis of Yangyu jiaotuan decreased considerably (by up to 42.08%) with the increase in PPI content and during refrigerated storage due to starch retrogradation. Protein has protected the microstructure and there was less damage when compared to samples without protein. The bimodal peaks of the particle size distribution curves showed that the newly developed Yangyu jiaotuan contains two different sizes of particles; the smaller particles (~30 μm) corresponded to PPI and starch granules, while the larger particles corresponded to the fragments of the gel network of the starch matrix. Based on the above results, Yangyu jiaotuan mixed with pea protein is a convenient potato staple food product, which complies with the biomimetic potato food very well. Full article

The aim of this study was to determine the effects of different varieties, year and location of growing, and their interactions, on wheat starch and flour properties, and to analyze the relationship between these attributes. The set of 92 wheat samples chosen to cover wide ranges in the parameters commonly used for the assessment of wheat flour and starch properties was reduced to a representative set of 27 samples. The obtained results showed that wheat variety and year significantly affected maximum viscosity (MV), alpha–amylase activity (AA), amylose content (AM), volume proportion of A-, B- and C-starch granules, as well as gelatinization temperatures, while the year and location by year interaction had a significant effect on the falling number (FN). In this work, a number of significant correlations were observed among analyzed starch and flour properties. AA was mostly influenced by the changes in packing of starch granules and granule size distribution, while gelatinization temperatures were affected by particle size distribution. Additionally, when testing the suitability of the parameters for the estimation of alpha–amylase activity, it was determined that Amylograph was more reliable in predicting alpha–amylase than FN because it provided a better description of the state of flour starch complex. Full article

Native starch (NS) from different botanical origins (native rice/tapioca/oat starch, NRS/NTS/NOS) were hydrophobically modified by octenyl succinic anhydride (OSA), and the octenyl succinic (OS) groups were successfully introduced in the starch molecules which obtained OS-starch (OSRS, OSTS and OSOS) with different levels of modification (0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%) and degree of substitution (DS). The structural properties of the OS-starch, such as granule size, crystal, wettability and morphology were studied, and the OS-starch was used as particulate stabilizers to produce oil-in-water (O/W) Pickering emulsions. The emulsion index, droplet size distribution and microstructures of Pickering emulsions produced by different OS-starches were compared. OSA modification had almost no effect on the morphology or crystal structure types of three kinds of NS and OS-starch but markedly increased the contact angle and particle size distribution of OSRS, OSTS and OSOS. Esterification reaction of OSA and starch mainly occurred in amorphous regions of starch, and the OSA significantly improved the emulsifying capacity of OSRS, OSTS and OSOS granules and thus stabilized emulsions formed at higher levels (2.5% and 3.0%) of modification of OS-Starch exhibited better stability; the ability of OS-starch to stabilize Pickering emulsion was 3.0% OSRS > 3.0% OSOS > 3.0% OSTS, respectively. Observation and structural properties analysis of OS-starch granules and Pickering emulsion droplets showed that the number and thickness of the starch granules on the oil-water interface of the emulsion droplets increased with improvement of the OSA modification level, and an aggregation state was formed between the OS-starch granules, which was also enhanced with the OSA modification levels. These were all necessary for the Pickering emulsion stabilized by starch granules to remain in a steady state. Full article

Variations in starch pasting properties, considered an alternative potential quality classification parameter for rice starches, are directly controlled by the diverse starch molecular composition and structural features. Here, the starch characteristics of four rice cultivars (i.e., RD57, RD29, KDML105, and RD6) differing in pasting properties were assessed, and their relationship was determined. The results revealed that protein and moisture contents and their crystalline type were similar among the four rice starches. However, their molecular compositions and structures (i.e., reducing sugar and amylose contents, amylopectin branch chain-length distributions, granule size and size distribution, and degree of crystallinity) significantly varied among different genotypes, which resulted in distinct swelling, solubility, gelatinization, retrogradation, and hydrolytic resistance properties. The swelling power and gelatinization enthalpy (∆H) were positively correlated with C-type granule and relative crystallinity, but were negatively correlated with amylose content, B-type granule and median particle size (d(0.5)). Conversely, the water solubility and resistant starch content negatively correlated with C-type granule, but positively correlated with amylose content, B-type granule, and d(0.5). The gelatinization onset temperature (To(g)), and retrogradation concluding temperatures (Tc(r)), enthalpy (∆H(r)), and percentage (R%) were positively impacted by the amount of protein, amylose, and B1 chains (DP 13–24), while they were negatively correlated with short A chains (DP 6–12). Collectively, the starch physicochemical and functional properties of these Thai rice starches are attributed to an interplay between compositional and structural features. These results provide decisive and crucial information on rice cultivars’ suitability for consumption as cooked rice and for specific industrial applications. Full article

Litchi seed starches from six varieties, as compared with maize starch, were studied for their multilevel structures, thermal and digestion properties to understand the distinct feather of each variety and provide guidance for their utilization in multi-industries. The results showed different varieties of litchi seed starch shared similar appearances with granules in oval shape and with a smooth surface. Starch granules of all the varieties exhibited typical bimodal size distributions consisting of small (<40 μm) and large granules (40–110 μm), although their relative proportions were largely dependent on variety. Huaizhi had the largest D50 value, whilst Guiwei showed the lowest. All the litchi seed starches had A-type crystalline with relative crystallinity varying from 20.67% (Huaizhi) to 26.76% (Guiwei). Similarly, the semi-crystalline structure varied apparently with variety. As to the chain-length distribution, only slight differences were observed among varieties, except Huaizhi displayed apparently higher amylose content (34.3%) and Guiwei showed the lowest (23.6%). Significant differences were also present in the gelatinization properties. Huaizhi seed starch showed significantly higher gelatinization temperatures and lower enthalpy change than the others. The digestibility of cooked litchi seed starches was only slightly different among varieties, suggesting variety is not the most critical factor regulating the digestibility of cooked litchi seed starch. Full article