Relationship between physicochemical characteristics and in vitro digestibility of chestnut (Castanea mollissima) starch

Effects of soluble dietary fiber from pomegranate peel on the physicochemical properties and in-vitro digestibility of sweet potato starch

The effects of soluble dietary fiber (SDF) from pomegranate peel obtained through enzyme (E-SDF) and alkali (A-SDF) extractions on the structural, physicochemical properties, and in vitro digestibility of sweet potato starch (SPS) were investigated. The expansion degree of SPS granules, pasting viscosity, gel strength and hardness were decreased after adding E-SDF. The setback was accelerated in the presence of A-SDF but E-SDF delayed this effect during the cooling of the starch paste. However, the addition of A-SDF significantly reduced the breakdown of SPS and improved the freeze-thaw stability of starch gels, even at low concentrations (0.1 %), while E-SDF showed the opposite result. The structural characterization of SDF-SPS mixtures showed that A-SDF can help SPS form an enhanced microstructure compared with E-SDF, while polar groups such as hydroxyl group in E-SDF may bind to leached amylose through hydrogen bonding, leading to a decrease in SPS viscoelasticity. In addition, the results of in vitro digestion analysis indicated that A-SDF and E-SDF could decreased the digestibility of SPS and increased the content of resistant starch, especially when 0.5 % E-SDF was added. This study provides a new perspective on the application of SDF from pomegranate peel in improving starch-based foods processing and nutritional characteristics.

Impact of soluble soybean polysaccharide on the gelatinization and retrogradation of corn starches with different amylose content

Polysaccharides have a significant impact on the physicochemical properties of starch, and the objective of this study was to examine the effect of incorporating soluble soybean polysaccharide (SSPS) on the gelatinization and retrogradation of corn starches (CS) with varying amylose content. In contrast to high-amylose corn starch (HACS), the degree of gelatinization of waxy corn starch (WCS) and normal corn starch (NCS) decreased with the addition of SSPS. The inclusion of SSPS resulted in reduced swelling power in all CS, and led to a decrease in gel hardness of the starches. The intermolecular forces between SSPS and CS were primarily hydrogen bonding, and a gel network structure was formed, thereby retarding the short-term and long-term retrogradation of CS. Scanning electron microscopy results revealed that the addition of SSPS in starches led to a loose network structure with larger poles and a reduced ordered structure after retrogradation, as observed from the cross-section of formed gels. These findings suggested that SSPS has great potential for applications in starchy foods, as it can effectively retard both gelatinization and retrogradation of starches.

Starch spectra of Ampelopteris prolifera (Retz.) Copel, a new addition to the existing lexicon and its comparison with a local potato cultivar (Solanum tuberosum L. cv. Kufri Jyoti)

Novel kinds of starch spectra were generated from a lesser-known plant, making this investigation unique. The recent trend of starch characterization shows the establishment of novel bioresources from nonconventional unexplored databases. The present endeavor was made to obtain the starch fingerprint of Ampelopteris prolifera (rhizome) belonging to seedless vascular plants. For comparison, a commercial local cultivar of potato (Kufri Jyoti) was taken. The starch particle of A. prolifera shows much uniqueness depicting its novelty viz., crystallinity index of 60.04 %, powder diffractogram at (2θ scale)17.57° to 39.78°; this diffractogram pattern is reported from this study as newer one i.e. R type(whereas potato starch is CB type); characteristic peak at 2θ = 20.07° suggests starch-lipid complex formation and V type crystallinity (i.e. RS 5 type); FTIR spectra showing the presence of more short chain branching; high gelatinization temperature(84.62 ± 0.10), particle size and zeta value of A. prolifera is 4.00 ± 0.81 μm and - 18.91 ± 3.58 mV respectively. Bragg's peak from the single crystal X-ray diffraction has been generated for the first time of A. prolifera. Extraction of the starch particle was performed in chilled water. Therefore, the present study suggests wide-spectrum commercial utility and cost-effective production.

Avocado seed starch utilized in eco-friendly, UV-blocking, and high-barrier polylactic acid (PLA) biocomposites for active food packaging applications

Efficient and effective use of biopolymers, such as starch, has increasingly prompted interest due to the current environmental challenges. However, starch-based composites still show poor ductility along with water and oxygen permeability, which may not meet the requirements for food packaging standards. In this study, modified starch (m-St), isolated from the avocado seed and synthesized with tert-butyl acetoacetate (t-BAA), was embedded into polylactic acid (PLA) to design new eco-friendly composites. The developed biocomposites were found to exhibit high performance with outstanding mechanical properties in conjunction with remarkable light, water vapor, and oxygen blocking features for food packaging applications. PLA/m-St(1:6) 20 wt% composites showed a dramatic increase in elongation at break (EB%) from 3.35 to 27.80 % (about 730 % enhancement) and exhibited remarkable UV-blocking performance from 16.21 to 83.86 % for UVB, relative to pure PLA. Equally importantly, these biocomposites revealed significant improvement in oxygen and water vapor barrier performance by reducing their values from 1331 to 32.9 cc m-2 day-1 (indicating a remarkable reduction of 97.53 %) and 61.9 to 28 g m-2 day-1, respectively. This study can show the great potential of extracting starch from biowaste resources and transforming it into sustainable bio-based composites as a promising solution for food packaging applications.

Physicochemical properties of a novel chestnut porous starch nanoparticle

A novel chestnut porous starch nanoparticle (PSNP) was successfully synthesized, combining the properties of starch nanoparticle (SNP) and porous starch. The SNP obtained through ultrasonic and acid hydrolysis, exhibited a smaller particle size (173.9 nm) and a higher specific surface area (SSA) compared to native starch. After the synergistic hydrolysis by α-amylase and glucoamylase, the porous structure appeared on the surface of SNP. The prepared PSNP had a size of 286.3 nm and the highest SSA. In the adsorption experiments, PSNP showed higher capacities for adsorbing water, oil and methylene blue (MB) compared to other samples. The acid and enzymatic treatments resulted in a decrease in the levels of total starch content and amylose ratio. Furthermore, the treatments increased the levels of relative crystallinity (RC) and solubility, while decreasing the short-range ordered structure and swelling ratio at high temperatures. It was observed that the SSA of starch granules positively correlated with the MB and water adsorption capacity (WAC), solubility, and RC. These findings highlight the potential of the novel PSNP as an efficient adsorbent for bioactive substances and dyes.

Impact of using whole chestnut flour as a substitute for cake flour on digestion, functional and storage properties of chiffon cake: A potential application study

Developing fresh cake product with rich nutrition and high quality has become a hot spot in food industry. In this study, whole chestnut flour as a high-quality dietary source was successfully substituted for cake flour in the production of chestnut chiffon cake with 40-55% substitution rate, and its application prospects were further evaluated through studying nutritional and storage properties. The results showed that chestnut chiffon cake with 45% and 50% substitution rate could significantly increase the resistant component, scavenging activity and ferric reducing antioxidant power, surprisingly decrease predicted glycemic index to 54.05-57.28, and reduce the acetate/propionate ratio and Firmicutes/Bacteroidetes value for human gut microbiota as well. Comparatively, chestnut chiffon cake with 45% substitution rate had more application potential due to its higher free water retention at day 7 and higher resilience throughout the storage time. Overall, this study could provide valuable information for the development of modern nutritional cake industry.

Exploring the relationship between nutritional properties and structure of chestnut resistant starch constructed by extrusion with starch-proanthocyanidins interactions

Driven by the high economic value of chestnut, creating chestnut-based food with nutritional functions has become a hot spot in food industry. In this study, effect of hot-extrusion treatment (HEX) with starch-proanthocyanidins (PR) interactions (HEX-PR) on chestnut starch (CS) nutritional properties was evaluated from the perspective of structural changes. Results showed that HEX-PR promoted the formation of ordered structure of CS containing single helix, V-type crystalline structure, and starch aggregates, thus increasing the resistant starch (RS) content from 3.25 % to 12.35 %. For the nutritional evaluation, the α-amylase inhibitory activity, antioxidant activity and antiglycation activity of HEX-PR treated CS (HEX-PRS) were enhanced, and the enhancing effect became stronger as PR concentration rose. In addition, HEX-PRS increased the level of short-chain fatty acids (SCFAs), especially propionate, and meanwhile enriched beneficial intestinal bacteria especially the Bifidobacterium. Notably, correction analysis showed that the microbial community was closely related to the α-amylase inhibitory activity, antioxidant activity and antiglycation activity. Overall, this study provided an approach for improving the nutritional functions of starch, and could offer guidance for further investigations to improve the nutritional quality of chestnut starch-based foods.

Characteristics of physicochemical properties, structure and in vitro digestibility of seed starches from five loquat cultivars

Starch plays a pivotal role in food and other industries, necessitating the exploration of new starch sources to cater the substantial requirement. This study delved into the variations in the physicochemical properties, structure attributes and in vitro digestibility of seed starches extracted from five distinct loquat cultivars (Eriobotrya japonica L.). The starch extraction yield of loquat seeds was found to be 45.2 % as an average. Loquat seed starches were designated as having high-amylose starch (>50 %). The starch granules exhibited similar shapes, but granular size significantly varied across the cultivars. Loquat starches presented a C-type crystalline pattern with relative crystallinity from 17.14 % to 21.06 %. The short-range ordered structure of the starches differed with loquat cultivars. The swelling power, solubility and amylose leaching of loquat starches increased with increasing temperature, significantly varying among different cultivars. Gelatinization parameters exhibited significant variations among the loquat starches. Different loquat starches exhibited pronounced variations in paste clarity, water and oil absorption capacity. Marked differences were detected in proportions of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) across the five cultivars, with RS being particularly prominent fraction with an average of 84.30 %. These compressive findings offer valuable insights into the potential application of loquat seed starches in the formulation of foods and various industrial products.

Effects of Tremella fuciformis Mushroom Polysaccharides on Structure, Pasting, and Thermal Properties of Chinese Chestnuts (Castanea henryi) Starch Granules under Different Freeze-Thaw Cycles

The purpose of this study was to investigate the effect of Tremella fuciformis polysaccharides on the physicochemical properties of freeze-thawed cone chestnut starch. Various aspects, including water content, crystallinity, particle size, gelatinization, retrogradation, thermal properties, rheological properties, and texture, were examined. The results revealed that moderate freezing and thawing processes increased the retrogradation of starch; particle size, viscosity, shear type, hinning degree, and hardness decreased. After adding Tremella fuciformis polysaccharide, the particle size, relative crystallinity, and gelatinization temperature decreased, which showed solid characteristics. Consequently, the inclusion of Tremella fuciformis polysaccharide effectively countered dehydration caused by freezing and thawing, reduced viscosity, and prevented the retrogradation of frozen-thawed chestnut starch. Moreover, Tremella fuciformis polysaccharide played a significant role in enhancing the stability of the frozen-thawed chestnut starch. These findings highlight the potential benefits of incorporating Tremella fuciformis polysaccharides in starch-based products subjected to freeze-thaw cycles.

Effect of electron beam irradiation on granular cold-water swelling chestnut starch: Improvement of cold-water solubility, multiscale structure, and rheological properties

In this study, granular cold-water swelling (GCWS) starch was prepared from chestnut starch by ethanol-alkali method, after which it was further modified by electron beam irradiation (EBI) technique to investigate the effect of EBI on GCWS chestnut starch. It was shown that the alcohol-alkali treatment disrupted the starch double helix structure and the starch crystalline form had been changed from "C" to "V" type. On this basis, EBI continued to act on the disrupted starch chains and further cleaved the long chains into short chains, which significantly improved the solubility of starch to 90.08 % in cold water at a 24 kGy irradiation dose. Therefore, this study can broaden the application scope of starch and provide new ideas for GCWS starch applications in food and water-soluble pharmaceutical industries.

Understanding the structural contributions to the functional properties of chestnut starch high in resistant starch type-2

BACKGROUND

Chestnut has recently attracted attention because of its exceptional functional properties, which are mainly influenced by the structural properties of chestnut starch (CS). In this study, ten varieties of chestnut from the northern, southern, eastern, and western regions of China were selected, and their functional properties, including thermal properties, pasting properties, in vitro digestibility, and multi-scale structural characteristics were characterized. The relationship between structure and functional properties was clarified.

RESULTS

In the varieties that were studied, the pasting temperature of CS was in the range of 67.2-75.2 °C and the pastes displayed diverse viscosity characteristics. Slowly digestible starch (SDS), and resistant starch (RS) of CS were in the range of 17.17-28.78% and 61.19-76.10%, respectively. Chestnut starch from north-eastern China exhibited the highest RS content of 74.43-76.10%. Structural correlation analysis revealed that smaller size distribution, fewer B2 chains, and thinner lamellae thickness contributed to higher RS content. Meanwhile, CS with smaller granules, more B2 chains, and thicker amorphous lamellae displayed lower peak viscosities, stronger resistance to shear, and higher thermal stability.

CONCLUSION

Overall, this study clarified the relationship between the functional properties and the multi-scale structure of CS, revealing the structural contributions to its high RS content. These findings provide significant information and basic data for use in the creation of nutritional chestnut food. © 2023 Society of Chemical Industry.

Insights into the changes of structure and digestibility of microwave and heat moisture treated quinoa starch

In this study, quinoa starch was subjected to microwave and heat moisture treatment (MHT) with various moisture content (15 %, 25 %, 35 %) and microwave power (4.8, 9.6, 14.4 W/g), and its structure and digestibility were investigated. SEM and particle size analysis indicated that MHT caused the agglomeration of starch granules and increased the particle size. Moreover, MHT increased the short-range order structure and relative crystallinity, except for MHT with moisture content (35 %). DSC results demonstrated that the gelatinization temperature and gelatinization enthalpy had a slight improvement after MHT. Moreover, MHT increased the amylose content to some extent. It was worth noting that the digestibility of quinoa starch significantly decreased. After MHT, a part of rapidly digestible starch (RDS) was converted into slowly digestible starch (SDS) or resistant starch (RS). Particularly, when moisture content was 25 %, the starch had a highest SDS + RS content. Thus, this study provided a potential approach using MHT to modulate the digestibility of starch.

Debranching facilitates malate esterification of waxy maize starch and decreases the digestibility

In this study, the debranching followed by malate esterification was employed to prepare malate debranched waxy maize starch (MA-DBS) with a high degree of substitution (DS) and low digestibility using malate waxy maize starch (MA-WMS) as the control. The optimal esterification conditions were obtained using an orthogonal experiment. Under this condition, the DS of MA-DBS (0.866) was much higher than that of MA-WMS (0.523). A new absorption peak was generated at 1757 cm^-1 in the infrared spectra, indicating the occurrence of malate esterification. Compared with MA-WMS, MA-DBS had more particle aggregation, resulting in an increase in the average particle size from scanning electron microscopy and particle size analysis. The X-ray diffraction results showed that the relative crystallinity decreased after malate esterification, in which the crystalline structure of MA-DBS almost disappeared, which was consistent with the decrease of decomposition temperature by thermogravimetric analysis and the disappearance of the endothermic peak by differential scanning calorimeter. In vitro digestibility tests showed an order: WMS > DBS > MA-WMS > MA-DBS. The MA-DBS showed the highest content of resistant starch (RS) of 95.77 % and the lowest estimated glycemic index of 42.27. In a word, pullulanase debranching could produce more short amylose, promoting malate esterification and improving the DS. The presence of more malate groups inhibited the formation of starch crystals, increased particle aggregation, and enhanced resistance to enzymolysis. The present study provides a novel protocol for producing modified starch with higher RS content, which has potential application in functional foods with a low glycemic index.

Characterization of chestnut starch acetate with different degrees of substitution

Chestnut starch acetates (CSA) with different degrees of substitution (DS) were prepared. The structure and physicochemical properties of CSA were then determined, with scanning electron microscopy showing that most of the CSA granules were damaged and dented, and adhered with increased in DS. X-ray diffraction results indicated that the crystal form of CS and CSA was type C. Chemical structure analysis showed that the starch molecule was grafted with acetyl groups. The transparency, freeze–thaw stability, solubility and swelling power of CSA improved with an increase in DS. The viscosity and stability of CSA were significantly improved and pasting temperatures reduced compared with native CS. The cohesion, hardness, gumminess, chewiness and springiness of CSA decreased with an increase in DS, whereas adhesiveness increased. By comparing the properties of CSA with different DS, a new option was provided for the application of renewable natural polymer CSA in food fields.

Extraction and characterization of waxy and normal barley β-glucans and their effects on waxy and normal barley starch pasting and degradation properties and mash filtration rate

Interactions between β-glucan and starch influence the health benefits of barley-based foods and barley brewing performance. Here, we characterized β-glucans from waxy and normal barley varieties and compared the effects of different β-glucans on the pasting and degradation of waxy and normal barley starches as well as the filterability of mashes from unmalted waxy and normal barley. Waxy barley Zangqing18 β-glucan displayed more compact micrographic features, higher molecular weight, larger particle size, higher thermal decomposition temperature and lower rheological viscosity than normal barley Zangqing2000 β-glucan. β-Glucan not only significantly decreased the pasting viscosities of waxy and normal starches but also lowered the pasting temperatures and peak times of normal starch, likely by inhibiting granule swelling and disrupting the integrity of the continuous phase. β-Glucan also decreased in vitro digestion extent of starch and increased the resistant starch. The unmalted waxy barley had a mash filtration rate much faster than normal barley because starch and β-glucan in waxy barley were rapidly and completely digested and formed more open filter passages. The effects of β-glucan on starch properties varied with the types and contents of β-glucans, whilst the types of starches showed more significant effects. CHEMICAL COMPOUNDS STUDIED: β-Glucan (Pubchem CID: 439262); Amylopectin (Pubchem CID: 439207); Starch (Pubchem CID: 156595876).

Structural and Physicochemical Properties of Starch from Rejected Chestnut: Hydrothermal and High-Pressure Processing Dependence

The quality standards for the export of chestnuts generate large quantities of rejected fruits, which require novel processing technologies for their safe industrial utilization. This study aimed to investigate the impact of high-pressure processing (HPP) and hydrothermal treatments (HT) on the physicochemical properties of rejected chestnut starch. Chestnuts were treated by HPP at 400, 500, and 600 MPa for 5 min and HT at 50 °C for 45 min. In general, all HPP treatments did not induce starch gelatinization, and their granules preserved the integrity and Maltese-cross. Moreover, starch granules' size and resistant starch content increased with the intensity of pressure. Native and HT chestnut starches were the most susceptible to digestion. HPP treatments did not affect the C-type crystalline pattern of native starch, but the crystalline region was gradually modified to become amorphous. HPP-600 MPa treated starch showed modified pasting properties and exhibited the highest values of peak viscosity. This study demonstrates for the first time that after HPP-600 MPa treatment, a novel chestnut starch gel structure is obtained. Moreover, HPP treatments could increase the slow-digesting starch, which benefits the development of healthier products. HPP can be considered an interesting technology to obtain added-value starch from rejected chestnut fruits.

A Novel Starch from Talisia floresii Standl Seeds: Characterization of Its Physicochemical, Structural and Thermal Properties

Colok seed (Talisia floresii Standl) represents 80% of the total fruit weight and is obtained from trees that grow mainly in Yucatan Peninsula. The aim of this work was the physicochemical characterization from colok starch seeds as an alternative to conventional sources and to identify its characteristics for potential applications in different industrial sectors. Starch yield was 42.1% with low levels of lipids, ashes and fibers. The amylose content was 33.6 ± 1.15%. The gelatinization temperature was 85 ± 0.25 °C. Color analysis resulted in a starch with an intermediate luminosity, reflecting a dark color. Finally, in morphology, starch granule exhibited an average size of 18.7 μm, spherical, uniform and without fractures. Overall results demonstrated that isolated colok starch can be used in food products that require high processing temperatures, such as sauces, cookies, noodles, bread and food packages.

Genetic Diversity and Population Structure of Chinese Chestnut (Castanea mollissima Blume) Cultivars Revealed by GBS Resequencing

Chinese chestnut (Castanea mollissima Bl.) is one of the earliest domesticated and cultivated fruit trees, and it is widely distributed in China. Because of the high quality of its nuts and its high resistance to abiotic and biotic stresses, Chinese chestnut could be used to improve edible chestnut varieties worldwide. However, the unclear domestication history and highly complex genetic background of Chinese chestnut have prevented the efficiency of breeding efforts. To explore the genetic diversity and structure of Chinese chestnut populations and generate new insights that could aid chestnut breeding, heterozygosity statistics, molecular variance analysis, ADMIXTURE analysis, principal component analysis, and phylogenetic analysis were conducted to analyze single nucleotide polymorphism data from 185 Chinese chestnut landraces from five geographical regions in China via genotyping by sequencing. Results showed that the genetic diversity level of the five populations from different regions was relatively high, with an observed heterozygosity of 0.2796-0.3427. The genetic diversity level of the population in the mid-western regions was the highest, while the population north of the Yellow River was the lowest. Molecular variance analysis showed that the variation among different populations was only 2.07%, while the intra-group variation reached 97.93%. The Chinese chestnut samples could be divided into two groups: a northern and southern population, separated by the Yellow River; however, some samples from the southern population were genetically closer to samples from the northern population. We speculate that this might be related to the migration of humans during the Han dynasty due to the frequent wars that took place during this period, which might have led to the introduction of chestnut to southern regions. Some samples from Shandong Province and Beijing City were outliers that did not cluster with their respective groups, and this might be caused by the special geographical, political, and economic significance of these two regions. The findings of our study showed the complex genetic relationships among Chinese chestnut landraces and the high genetic diversity of these resources.

A Review of the Stress Resistance, Molecular Breeding, Health Benefits, Potential Food Products, and Ecological Value of Castanea mollissima

Chestnut (Castanea spp., Fagaceae family) is an economically and ecologically valuable species. The main goals of chestnut production vary among species and countries and depend on the ecological characteristics of orchards, agronomic management, and the architecture of chestnut trees. Here, we review recent research on chestnut trees, including the effects of fungal diseases (Cryphonectria parasitica and Phytophthora cinnamomi) and insect pests (Dryocosmus kuriphilus Yasumatsu), molecular markers for breeding, ecological effects, endophytic fungi, and extracts with human health benefits. We also review research on chestnut in the food science field, technological improvements, the soil and fertilizer used for chestnut production, and the postharvest biology of chestnut. We noted differences in the factors affecting chestnut production among regions, including China, the Americas, and Europe, especially in the causal agents of disease and pests. For example, there is a major difference in the resistance of chestnut to C. parasitica in Asian, European, and American countries. Our review provides new insights into the integrated disease and pest management of chestnut trees in China. We hope that this review will foster collaboration among regions and help to clarify differences in the direction of breeding efforts among countries.

Influence of ultrasound and microwave treatments on the structural and thermal properties of normal maize starch and potato starch: A comparative study

The effects of ultrasound and microwave on the physicochemical properties of normal maize and potato starches were compared. The cavitation effect of ultrasound loosened the internal space and destroyed the structure of starch granules, increased the damaged starch content, which was consistent with the decrease in relative crystallinity and the number and brightness of Maltese crosses, and the increase in D(0.5) and D(4,3) values. Microwave vibrated the molecules inside the granules and generated heat to destroy the structure of starch. The content of damaged starch was significantly lower in microwave-treated starch compared with ultrasound-treated starch. Microwave treatment promoted the formation of amylose-lipid complex, with the larger peak area at 20°(2θ) than that of the ultrasound-treated starch. The type of starch and the treatment sequence showed a significant effect. The results might help understand the mechanism of ultrasound and microwave treatments influencing the structural properties of starches.

Physicochemical characteristics and in vitro digestibility of starches from colored quinoa (Chenopodium quinoa) varieties

The quinoa flour processing is mostly subject to the properties of starch. Starches from four colored quinoa varieties, including white quinoa (QS-W), yellow quinoa (QS-Y), red (QS-R), and black (QS-B), were compared with respect to their physicochemical properties and in vitro digestibility. Results indicated that QS-B exhibited the highest content of amylose (8.14%) (p < 0.05). All starch samples exhibited as irregular sphere with a particle size less than 3 µm. Results of the FT-IR and X-ray showed that the short-range order of the four quinoa starches exhibited no significant difference; all starches showed a typical A-type diffractrometric pattern and was not affected by seed color, and QS-Y had the highest relative crystallinity (34.3%) (p < 0.05). In addition, QS-W reflected the highest solubility (6.32%) and QS-Y showed the highest swelling power (19.45 g/g) (p < 0.05). QS-Y also presented a higher ΔH value (11.46 J/g) (p < 0.05), while QS-R peak temperature and peak G' were the lowest. Besides, QS-B had the highest slow-digestible starch (SDS) and resistant starch (RS) content, while the lowest estimated glycemic index (eGI) value (p < 0.05). Also, there was a negative correlation between hydrolysis rates and amylose content of quinoa starch. PRACTICAL APPLICATION: Due to the low gelatinization temperature of quinoa starch, it can be used to both produce and improve instant and fast food products. Quinoa starch particles are small, and Pickering emulsions and additives have potential application values. Red quinoa contains easily digestible starch, which can be a good food choice for infants and the elderly, while white quinoa starch has less swelling power and can be used in noodle products. The results of this study can help to underpin the study of quinoa nonstarch components versus starch component.

Effect of four viscous soluble dietary fibers on the physicochemical, structural properties, and in vitro digestibility of rice starch: A comparison study

The effect of carboxymethyl cellulose (CMC), high-methoxyl pectin (HMP), konjac glucomannan (KGM), and xanthan gum (XG) on the physicochemical, structural properties, and digestibility of rice starch were investigated and compared. The four viscous soluble dietary fibers (VSDFs) increased the viscosity, storage modulus and loss modulus while decreased the pasting temperature and gelatinization enthalpy. Moreover, XG produced the lowest peak viscosity and dynamic modulus compared with the other VSDFs. Furthermore, the degree of short-range ordered structure of starch with KGM increased from 0.8448 to 0.8716; and the relative crystallinity of starch with XG increased by 12%. An ordered and reunited network structure was observed in SEM. In addition, VSDF inhibited the digestibility of rice starch and significantly increased the resistant starch content. This study compared the effect of four VSDFs on the physicochemical, structural and digestion properties of rice starch to fully understand and develop their application to starchy foods.

Chickpea and Chestnut Flours as Non-Gluten Alternatives in Cookies

This study proposes the use of a mix composed of chickpea flour and chestnut flour in cookies, aiming to improve their acceptability. Cookie properties and nutritional value were also analysed. The gluten-free cookies were made by using different mixes of chickpea and chestnut flours (0:100, 25:75, 50:50, 75:25, 100:0). Dough rheology and cookie dimensions, texture, external colour and acceptability were evaluated. The presence of the chestnut flour increased the values of G' and G", but reduced the loss factor (tan δ) when compared with the doughs made with chickpea flour. Chestnut flour also decreased the diameter and the spread ratio of the cookies, while increasing the hardness and darkening of the cookies. Furthermore, adding chestnut to the flour mixture increased the nutritional quality of the cookies by adding unsaturated fatty acids and fibre. The use of reduced percentages of chestnut flour (25%) resulted in masking the off-flavour of the chickpea flour, which improved the cookie's acceptability without significantly changing the dough rheology, cookie dimensions, hardness, or lightness.

Transcriptome analysis of genes involved in starch biosynthesis in developing Chinese chestnut (Castanea mollissima Blume) seed kernels

Chinese chestnut (Castanea mollissima Blume) seed kernels (CCSK) with high quality and quantity of starch has emerged as a potential raw material for food industry, but the molecular regulatory mechanism of starch accumulation in developing CCSK is still unclear. In this study, we firstly analyzed the fruit development, starch accumulation, and microscopic observation of dynamic accumulation of starch granules of developing CCSK from 10 days after flowering (DAF) to 100 DAF, of which six representative CCSK samples (50–100 DAF) were selected for transcriptome sequencing analysis. Approximately 40 million valid reads were obtained, with an average length of 124.95 bp, which were searched against a reference genome, returning 38,146 unigenes (mean size = 1164.19 bp). Using the DESeq method, 1968, 1573, 1187, 1274, and 1494 differentially expressed unigenes were identified at 60:50, 70:60, 80:70, 90:80 and 100:90 DAF, respectively. The relationship between the unigene transcriptional profiles and starch dynamic patterns in developing CCSK was comparatively analyzed, and the specific unigenes encoding for metabolic enzymes (SUSY2, PGM, PGI, GPT, NTT, AGP3, AGP2, GBSS1, SS1, SBE1, SBE2.1, SBE2.2, ISA1, ISA2, ISA3, and PHO) were characterized to be involved potentially in the biosynthesis of G-1-P, ADPG, and starch. Finally, the temporal transcript profiles of genes encoding key enzymes (susy2, pgi2, gpt1, agp2, agp3, gbss1, ss1, sbe1, sbe2.1, sbe2.2, isa1, isa2, isa3, and pho) were validated by quantitative real-time PCR (qRT-PCR). Our findings could help to reveal the molecular regulatory mechanism of starch accumulation in developing CCSK and may also provide potential candidate genes for increasing starch content in Chinese chestnut or other starchy crops.

Modulating the in vitro digestibility of chemically modified starch ingredient by a non-thermal processing technology of ultrasonic treatment

Chemically modified starch (RS4) was commercially available as a food ingredient, however, there was a lack of knowledge on how ultrasonic treatment (non-thermal technology) modulated the enzymatic resistance of RS4. In this study, structural change of RS4 during ultrasonic treatment and its resulting digestibility was investigated. Results from scanning electron microscopy, particle size analysis, chemical composition analysis, X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy showed that ultrasonic treatment remained the granule morphology, increased the apparent amylose content, reduced the particle size, destroyed the crystalline structure, decreased the helical orders, but enhanced the short-range molecular orders of ultrasonic-processed RS4. In vitro digestibility analysis showed that the total content of rapidly digestible starch and slowly digestible starch was increased, whereas the content of resistant starch was decreased. Overall, ultrasonic treatment substantially reduced the enzymatic resistance of RS4, indicating that RS4 was not stability against the non-thermal processing technology of ultrasonic treatment.

Effect of Ultrasonic and Microwave Dual-Treatment on the Physicochemical Properties of Chestnut Starch

This work examined the effect of ultrasound and microwave treatments, separate and in combination, on the physicochemical and functional properties of chestnut starch. The results revealed that the ultrasonic-microwave (UM) and microwave-ultrasonic (MU) dually modified samples exhibited more severe surface damage, weaker birefringence, and lower relative crystallinity and gelatinization enthalpy than the native and single-treated starches. The UM samples showed the highest oil absorption capacity, and the MU samples showed the highest water absorption capacity and the best freeze-thaw stability (five cycles) among all samples. The swelling power, peak, trough, final, and breakdown viscosities, and pasting temperature all decreased regardless of single or dual modification. This study provides a reference for potential industrial applications of ultrasound and microwave treatments for the modification of chestnut starch.

Reducing the glycemic impact of carbohydrates on foods and meals: Strategies for the food industry and consumers with special focus on Asia

Type 2 diabetes is increasingly prevalent in Asia, which can be attributed to a carbohydrate-rich diet, consisting of foods in the form of grains, for example, rice, or a food product made from flours or isolated starch, for example, noodles. Carbohydrates become a health issue when they are digested and absorbed rapidly (high glycemic index), and more so when they are consumed in large quantities (high glycemic load). The principal strategies of glycemic control should thus aim to reduce the amount of carbohydrate available for digestion, reduce the rate of digestion of the food, reduce the rate of glucose absorption, and increase the rate of glucose removal from blood. From a food perspective, the composition and structure of the food can be modified to reduce the amount of carbohydrates or alter starch digestibility and glucose absorption rates via using different food ingredients and processing methods. From a human perspective, eating behavior and food choices surrounding a meal can also affect glycemic response. This review therefore identifies actionable strategies and opportunities across foods and meals that can be considered by food manufacturers or consumers. They are (a) using alternative ingredients, (b) adding functional ingredients, and (c) changing processing methods and parameters for foods, and optimizing (a) eating behavior, (b) preloading or co-ingestion of other macronutrients, and (c) meal sequence and history. The effectiveness of a strategy would depend on consumer acceptance, compatibility of the strategy with an existing food product, and whether it is economically or technologically feasible. A combination of two or more strategies is recommended for greater effectiveness and flexibility.

Understanding the mechanism of ultrasonication regulated the digestibility properties of retrograded starch following vacuum freeze drying

The digestibility properties and structural changes of retrograded starch (RS3) induced by ultrasonic treatment (UT) were investigated. The digestion profiles showed that UT increased the slowly digestible starch (SDS) or resistant starch (RS) of RS3 as an effective green process, corresponding to a change in hydrolysis kinetic parameters (equilibrium starch hydrolysis percentage and kinetic constant). SEM analysis showed that ultrasound led to breakage of RS3 particles followed by cracking, reorientation and crystallization. Differences in amylose content, granule size, and ζ-potential were found for native RS3 and ultrasound-treated RS3 (UT-RS3). UT decreased the relative crystallinity and gelatinization enthalpy but enhanced short-range order of RS3 based on the results of XRD, DSC, and FT-IR, respectively. Surprisingly, diffractive peaks at 13°and 20° (V-type crystalline structure) and a new exothermic peak were also observed for UT-RS3. The outcome was believed to open new pathways for regulating the digestibility properties of RS3 by UT and development of low glycemic response food.

Effect of Heat-Moisture Treatment on Physicochemical, Thermal, Morphological, and Structural Properties of Mechanically Activated Large A- and Small B-Wheat Starch Granules

The large and small granules of A-starch (AS) and B-starch (BS) were separated from wheat cultivar of ZM 22. It was modified by ball-milling (BM) and heat-moisture treatment (HMT) was performed after BM treatment. After BM, noticeable deformation, fragments, fissures, and grooves were observed, whereas diffusion and aggregation were detected and followed by HMT. Crystallinity of AS-BM-5h decreased to 7.8%, and no diffraction peaks were observed for BS. However, after HMT, the crystallinity of AS-BM-5h and BS-BM-5h was increased to 17.4% and 6.2%, respectively. AS-BM-HMT displayed better thermal stability. After being treated by BM previously, AS and BS showed an increase in solubility, whereas the subsequent HMT of BM-treated starches (both AS and BS) had higher solubility especially for BS with longer BM treatment time. Large-sized granules were easier to be damaged by BM, whereas small-sized granules were greatly influenced by HMT. Dual modification of BM-HMT was an effective and potential method to modify the structure of wheat starch granules and expand its industrial applications. PRACTICAL APPLICATION: This study put forward a new dual modification method in combination with BM-HMT for large A-starch and small B-starch granules. Flour processing inevitably causes some starch to be damaged by destroying the structure. How can the damaged starch structure be improved to satisfy the food processing industry? HMT was proposed to modify the mechanically activated starches because of its obvious effects on smaller BS. HMT can reduce the content of damaged starch by rearranging and reorganizing its structures. This study can provide a low-cost, convenient, and eco-friendly technology for improving damaged starch and developing its applications in food industry.

Comparison of Physicochemical Properties of Starches from Nine Chinese Chestnut Varieties

Chestnut is a popular food in many countries and is also an important starch source. In previous studies, physicochemical properties of starches have been compared among different Chinese chestnut varieties growing under different conditions. In this study, nine Chinese chestnut varieties from the same farm were investigated for starch physicochemical properties to exclude the effects of growing conditions. The dry kernels had starch contents from 42.7 to 49.3%. Starches from different varieties had similar morphologies and exhibited round, oval, ellipsoidal, and polygonal shapes with a central hilum and smooth surface. Starch had bimodal size distribution and the volume-weighted mean diameter ranged from 7.2 to 8.2 μm among nine varieties. The starches had apparent amylose contents from 23.8 to 27.3% but exhibited the same C-type crystalline structure and similar relative crystallinity, ordered degree, and lamellar structure. The gelatinization onset, peak, and conclusion temperatures ranged from 60.4 to 63.9 °C, from 64.8 to 68.3 °C, and from 70.5 to 74.5 °C, respectively, among nine starches; and the peak, hot, breakdown, final, and setback viscosities ranged from 5524 to 6505 mPa s, from 3042 to 3616 mPa s, from 2205 to 2954 mPa s, from 4378 to 4942 mPa s, and from 1326 to 1788 mPa s, respectively. The rapidly digestible starch, slowly digestible starch, and resistant starch ranged from 2.6 to 3.7%, from 5.7 to 12.7%, and from 84.4 to 90.7%, respectively, for native starch, and from 79.6 to 89.5%, from 1.3 to 3.8%, and from 7.1 to 17.4%, respectively, for gelatinized starch.