Partial Gelatinization Research Articles

Dual modification of starch: Synergistic effects of ozonation and pulsed electric fields on structural, rheological, and functional attributes

Study evaluated the influence of ozonization (O3) time combined with pulsed electric fields (PEF) on the modification of bean starch structure. O₃ was used at a concentration of 0.045 g/L for 60 min (Oz1) and 120 min (Oz2) both individually and in combination with 30 kV/cm (P30). Carbonyl content was higher than the carboxyl content, especially with prolonged treatment times (Oz2), indicating partial oxidation. Additionally, higher levels of amylose and degrees of polymerization (DP ≥ 37 and DP 25–36) were observed in the oxidized starches, with significant changes only when combined with PEF. The main morphological and structural modifications included the presence of agglomerates, partial gelatinization, reduced crystallinity, and lower IR1047/1022 in the granules treated with PEF + O3. Oxidized starches exhibited higher solubility, resulting in lower values for rheological parameters, with PEF + 2 h of O3 (Oz2P) standing out. It can be used as prebiotics, controlled release agents and a texturizer for gluten-free foods.

Insight into the multi-scale structure and retrogradation of corn starch by partial gelatinization synergizing with epicatechin/epigallocatechin gallate

Starch retrogradation is of great importance to the quality of starch-based food. This study investigated the effect of partial gelatinization (PG) synergizing with polyphenol (epicatechin, EC; epigallocatechin gallate, EGCG) on the multi-scale structure and short/long-term retrogradation of corn starch (CS). The PG synergizing with EC/EGCG substantially suppressed the short/long-term retrogradation properties of CS. These could be confirmed by the decreased storage modulus and viscosity, the relative crystallinity (1.54%, 3.56%), and the retrogradation degree (9.99%, 20.18%) of CS during storage for 1, 14 days after PG synergizing with EGCG and EC, respectively. This is because PG treatment promoted the hydrogen bond interaction between disordered starch molecules and EC/EGCG. These were proven by the larger aggregation, more and brighter fluorescents, and the reduced long/short-range order structures in CS after PG synergizing with EC/EGCG. This study is helpful for the development of foods with enhanced nutrition and low-retrogradation.

Interactions of Native Maize Starch Components with Pectin Using Extrusion

AbstractNative starch exhibits undesirable properties in the final product when used as an additive. Recently, the effects of the interaction between starch and hydrocolloids on the techno‐functional properties of starch have been studied. However, this interaction has not yet been applied to a real food system. Therefore, in this work, the techno‐functional properties of starch–pectin complexes formed by extrusion are investigated. Mixtures of isolated native Pozolero maize starch “HPZ1” and pectin of low degree of methyl‐esterification at four concentrations (0%, 2%, 5%, and 7%) are used. The starch–pectin blends are processed in a single screw extruder with constant variables: temperature, screw speed, and moisture. Morphology, X‐ray diffraction, thermal properties, and techno‐properties are studied. A protective effect of pectin on the starch granules is observed, as evidenced by a matrix involving starch granules. Extrusion results in a partial gelatinization of the starch granules and alters their thermal and pasting properties with the peak temperature increasing with increasing pectin concentration. Extrusion allows both carbohydrates to interact with each other. Finally, the results show that the starch–pectin complexes are ingredients with desirable techno‐functional properties that can be integrated into a food system and add value to Mexican criollo maize.

Structural modification of starch and protein: From the perspective of gelatinization degree of oat flour

To clarify the relationship between gelatinization degree and structure characteristics, oat kernels were roasted to different gelatinization degree of 15 %–90 % based on tempering water content of 22.5 %–35 %, and the structure characteristics of starch and protein were evaluated. The results showed that the increased gelatinization degree dependent on tempering water content promoted protein aggregation on the surface of starch particles, forming larger aggregates with molecular weight >100 kDa. Oat kernels presented a dense starch gel network structure induced by gelatinized starch. Partial gelatinization of starch led to a decrease in pasting viscosities (setback viscosity, 3.91 Pa·s–1.59 Pa·s) and enthalpy (5.12 J/g–0.11 J/g). With the increase of gelatinization degree, the starch crystal structure conversed from A + V type to V type, accompanied by the formation of starch-lipid complexes and a decrease of relative crystallinity (22.28 %–8.72 %). Moreover, 50 % gelatinized oat flour possessed the highest β-sheet structure (38.04 %), but a decrease in surface hydrophobicity and an increase in endogenous fluorescence intensity were found in oat flour of gelatinization degree >50 %. This study provided a theoretical reference for the application of oat flour with different gelatinization degrees to match suitable products.

Humidity-controlled heat treatment of fresh spinach noodles for color preservation and storage quality improvement

The high sensitivity to color browning during room-temperature storage was a significant factor in limiting the development of fresh spinach noodles (FSN). The practice of humidity-controlled heat treatment (HCHT) at varying temperatures, relative humidity, and time was carried out to limit enzyme activity and improve the quality of FSN. Results showed that HCHT could maximize the color preservation of fresh spinach noodle quality while effectively inactivating polyphenol oxidase and the yeasts, and mold count in FSN during storage was almost undetectable after mild conditions (80 °C). The hardness and chewiness of HCHT noodles were significantly increased, but the free sulfhydryl content was reduced. At 80 °C, 90 %, 5 min, protein structural aggregation was found in the microstructure of HCHT fresh spinach noodles. HCHT also caused partial gelatinization, as evidenced by the decrease in starch gelatinization enthalpy from 5.49 to 4.77 J/g, although the gelatinization degree of FSN was comparatively low.

Impact of Ingredients Formulation and Processing Parameters on the Nutritional Quality of Foam-mat Dried Kunun-zaki Powder (A Nigerian fermented Cereal Beverage)

The study investigated the effects of different ingredient formulations and processing parameters on the proximate composition and sensory qualities of foam-mat dried kunun-zaki, a traditional Nigerian beverage. The research was conducted in two stages using a mixture-process design matrix. In the first stage, kunun-zaki was produced by steeping grains (millet, maize, and soybean) for varying durations, wet milling with other ingredients (ginger, sweet potatoes, pepper, and moringa seeds), and partial gelatinization of the slurry. The second stage involved foam-mat drying at different temperatures (40 and 70°C). The proximate composition evaluated included moisture content, ash content, crude protein, crude fiber, and fat, while sensory properties like color, flavor, taste, mouthfeel, and overall acceptability were also assessed. Numerical optimization through desirability technique was employed to determine the optimum formulation and process parameters for foam-mat dried kunun-zaki. The study found that the best quality product had 9.595% moisture content, 2.552% ash content, 28.195% crude protein, 54.443% carbohydrate, 11.949% fat, and 5.828% crude fiber. This quality was achieved using a drying temperature of 40.00°C and a steeping period of 12.0 hours, with 48.435% millet and 51.565% soya bean, and no maize in the formulation, resulting in a desirability index of 0.625.

Effects of glutathione on structural and digestibility properties of high-hydrostatic-pressure-gelatinized maize starch with different amylose/amylopectin ratios

The effect of glutathione (GSH) on the digestibility, physicochemical, and structural properties of maize starch under 600 MPa for 20 min of high hydrostatic pressure (HHP) treatment was determined by in vitro digestion, differential scanning calorimetry (DSC), scanning electronic microscopy (SEM), particle size distribution analysis, Fourier transforms infrared spectroscopy (FT-IR), and Laser Confocal Raman (LC-Raman) microscopy. The findings indicate that the waxy maize starch (WMS) underwent complete gelatinization, whereas the high amylose starches had partial gelatinization. GSH induced a significant increase (p ≤ 0.05) in the slowly digestible starch (SDS) content and a decrease in the rapidly digestible starch (RDS) after HHP treatment. Thermal analysis revealed that GSH increased starch gelatinization temperature. The gelatinization characteristics showed that GSH inhibited starch retrogradation but did not contribute much to starch crystallinity. FT-IR and LC-Raman analyses confirmed the interaction of GSH with starch molecules. The present result emphasizes the impact of GSH on the modelling of starch digestibility and structure properties and inspires the development of new functional foods prepared with HHP.

Effect of processing conditions on the functional properties of starches during formulation of quick-cooking brown rice

The demand for ready-to-cook and nutritious products is on the rise due to the lifestyle becoming more hectic throughout the world. In this study, quick-cooking brown rice was formulated from four rice varieties. For each variety, the process was optimized by analyzing different combinations of soaking time (10, 20, and 30 min), drying time (20, 30, and 40 min), and drying temperature (60, 70, and 80 °C). Central composite design (CCD) was used to select the best combinations based on the least cooking time and moisture content within the range of 12–14%, and the same was different for each rice variety. To comprehend the effect of these processing conditions on rice, its main constituent i.e. starch, known to affect the palatability of rice cultivars was investigated. The starches were extracted from all the four quick-cooking brown rice samples and their properties were compared with respective native starches. Results obtained indicated that the treated starch samples from all varieties had better solubility and swelling behaviors. Treated starches also demonstrated higher retrogradation as compared to native starches. Untreated starches showed a well-defined polygonal structure of starch granules while treated starches showed distorted structures under scanning electron microscopy indicating their partial gelatinization. X-ray diffraction results indicated that in all the varieties of rice A-type starch was present, however, upon treatment diffraction peaks changed for all the varieties and the typical A-type structure of untreated starch shifted to CA-type starch structure. Readily digestible starches (RDS%) of all the treated starches increased while slowly digestible starches (SDS%) of all the treated starches decreased. Results indicated that both soaking time, drying time and drying temperature had significant effect on the physicochemical properties and digestibility of rice starches.

Preparation of starch‐lipid complexes under wet grinding and its mechanism analysis

AbstractBackground and ObjectiveStarch‐lipid complexes prepared by using partially gelatinized starch were more helpful in reducing the digestibility of starchy foods. Wet grinding (WG) could improve grinding homogeneity and avoid dust explosions. Moreover, as an excellent plasticizer, water could promote the movement of starch molecules during grinding. Therefore, this paper investigated the effect of WG on the structure and properties of corn starch with and without lauric acid. And the formation mechanism of starch‐lipid complexes under WG was explored.FindingsWG caused continuous hydration and even partial gelatinization of the starch. After 30 min of WG, the relative crystallinity, resistant starch (RS) content, and ΔH of the starch were all reduced to the minimum which were 25.82%, 21.55%, and 0.99 J/g, respectively. When lauric acid was added, WG promoted the formation of starch‐lipid complexes, and the RS content of starch reached the maximum (35.61%) after 30 min of WG.ConclusionAppropriate WG could promote the formation of more starch‐lipid complexes with low swelling, low solubility, high thermal stability, and high antidigestibility.Significance and NoveltyThis study provided a theoretical basis for future research on the preparation of high‐quality modified starch by WG.

The effects of accelerated storage on quality of cake prepared using hydrothermally infrared treated flours

This study aimed to determine some quality parameters, including moisture, weight loss, volume, color, and textural properties of cakes prepared using IR treated flours, and to investigate the effects of storage (30 days) on these parameters. Using IR treated flour resulted in a significant increase in moisture, hardness, gumminess, and chewiness values, while a significant decrease in weight loss and volume values in the cakes compared to the cake made of unprocessed flour (P < 0.05). On the other hand, weight loss, hardness, gumminess, and chewiness values increased, while volume and resilience values decreased in all cakes during the storage period due to moisture loss (P < 0.05). Consequently, hydrothermal IR treatment significantly affected the quality parameters and texture stability of cake due to the partial gelatinization of starch and denaturation of proteins. Thus, hydrothermal IR treatment can become an alternative method for the production of cake flour.

Insight into the Effects of Drying Methods on Lanzhou Lily Rehydration.

This study investigated the effects of drying methods (hot air drying (HAD), microwave vacuum drying (MVD), and vacuum freeze drying (VFD)) on the rehydration performance (RP) of dried Lanzhou lily scales (LLS). Rehydration rate and water migration showed that MVD had the best RP, followed by VFD, while HAD had the worst. The results of additional morphology observation using scanning electron microscopy (SEM) and micro X-ray computed tomography (CT) imaging showed that both MVD and VFD created more channels in more porous structures, which facilitated their better RP than that by HAD. The results also revealed the spatial structure diversity (including pores, channels size, and internal network) of each dried Lanzhou lily scale group. In addition, studies analyzed how drying techniques affected the physiochemical properties of lily starch, including its water solubility, pasting profiles, and starch particle morphology. The findings indicated that when MVD was in operation, partial gelatinization in lily starch was brought about by thermal effects, allowing MVDS crystals to change from B-type to V-type and causing MVDS to have better water absorption ability. Consequently, despite the fact that MVD's desiccated lilies have a lower porous structure and thinner channels than VFD's, MVD has a higher RP than VFD.

Multifunctional starch/carbon nanotube composites with segregated structure: Electrical conductivity, electromagnetic interference shielding effectiveness, thermal conductivity, and electro‐thermal conversion

AbstractConductive polymer composites with segregated structure (s‐CPCs) are widely used in the electronics industry. Achieving selective distribution of the conductive fillers in the polymer matrix is an effective way to construct s‐CPCs. In this work, the starch was used as the matrix and the carbon nanotube (CNT) was used as the conductive fillers to fabricate multifunctional s‐CPCs, via simple mechanical mixing and compression molding. During the processing, the starch underwent partial gelatinization, which was conducive to the fusion of the starch granules and the selective distribution of the CNT. Scanning electron microscope and atomic force microscope images showed that the CNT was attached to the surface of the starch granules to form a segregated structure. The starch/CNT composites exhibited a significant percolation, with a percolation threshold of 0.24 vol%. When the CNT content was 3.05 vol%, the starch/CNT composites exhibited a high electromagnetic interference (EMI) shielding effectiveness of 33.12 dB, which was commercially applicable in EMI shielding devices. The starch/CNT composites also possess good thermal management properties and can be used as thermal conductors and electro‐thermal conversion devices. This work manifests the application prospect in the field of the electronics industry and broadens the application potential of starch.

Influence of pre‐gelatinization in conjunction with guar gum addition on texture functionality, bioactive profile, in vitro nutrient digestibility, morphology and secondary structure of protein of quality protein maize pasta

SummaryThe current investigation aimed to develop quality protein maize (QPM) specialty pasta (partial: 50% QPM and full replacement of semolina: 100% QPM) and study the influence of pre‐gelatinization in conjunction with guar gum addition (1.5% or 3%) on bio‐techno‐functional properties of pasta. Scanning electron microscopy depicted the encapsulation of swollen starch within a protective sheet developed as a result of gum addition and starch gelatinisation. The Fourier transform infrared spectra denoted a shift from crystalline towards amorphous state in starch as a consequence of partial gelatinisation. The secondary structure of protein signified a drop in the alpha‐helix structure and thereby enhanced the in vitro protein digestibility of the pregelatinised samples. Multivariate principal component analysis was utilised to validate the differences between the parameters. The overall study inferred that the QPM owned an excellent potentiality for the development of nutrient‐dense pasta by employing the functionality of gums and pre‐gelatinisation treatment.

Effects of drying approaches combined with variable temperature and tempering on the physicochemical quality of rice

In this study, the effect of drying approaches in conjunction with variable temperature and tempering on the physicochemical quality of rice was investigated. The development of fissures, head rice yield, taste quality, textural properties, and microstructure of rice with different drying approaches were evaluated by employing principal component analysis (PCA). The results showed that increasing the tempering treatment could enhance the physicochemical quality of rice, and that the different drying approaches had a significant influence (P < 0.05) on the development of fissures, head rice yield, taste quality, and textural properties. High temperatures result in partial gelatinization of the starch, destruction of the starch granules, and an increase in fissures, as revealed by the microstructure of rice with different drying approaches. In addition, the drying approaches with a variable temperature of Δ0 (35 °C), Δ5 (45 °C–50 °C), and Δ0 (45 °C) in combination with the tempering treatment exhibited a high overall physicochemical quality. This study offers a point of reference for further research into the changes in the physicochemical quality of rice during drying.

Structural, gelatinization, and rheological properties of heat-moisture treated potato starch with added salt and its application in potato starch noodles

Gluten-free noodles, e.g. potato starch noodles, are getting popular due to the increasing population with gluten sensitivity and celiac disease. However, due to the lack of gluten network, the solid loss of potato starch noodles during cooking leads to lower textural and sensory attributes. The starch modification provides the opportunity to address these shortcomings. Here, we report the application of heat-moisture treated (HMT) potato starch with added salt as a binder to improve the cooking and textural properties of potato starch noodles. In the presence of sodium tripolyphosphate (STPP) and sodium chloride (SC), starch granules exhibited irregular shapes and deformed crystalline growth rings, agglomerated due to partial gelatinization, and lost double-helical structures and the perfection of crystallites after being subjected to HMT. As affected by the starch-ions interactions and changed water structure, HMT-modified starch with added SC and STPP had higher pasting temperatures, less amylose leaching, and lower gelatinization enthalpies and pasting viscosities than HMT starch without salts. Meanwhile, higher cross-over temperatures and lower G’ values were found in HMT starch with added STPP and SC compared to HMT starch. Iodine-staining micrographs also confirmed the delay in the disintegrating process of starch granules in HMT-modified starch with added SC and STPP. Furthermore, when HMT-modified starch with added SC was applied as binder paste, starch dough owned higher hardness and starch noodles exhibited less solid loss and broken noodles, firmer texture, and better elasticity. The results thus provide the opportunity to improve the textural attributes of potato starch noodles with the application of HMT potato starch and salt as the binder. • Structural changes of starch before and after HMT as affected by salts are studied. • Adding sodium chloride induces the losses of ordered structure of starch during HMT. • Adding salts delays the disintegrating of starch granules during gelatinization. • HMT starch with added sodium chloride (HPS-SC) has better heat and shear stability. • HPS-SC as a binder improves cooking performance and texture of starch noodles.

Impact of microwave radiation on in vitro starch digestibility, structural and thermal properties of rice flour. From dry to wet treatments

Microwave radiation (MW) is an environment-friendly technology used to physically modify flours. Rice flour was MW-treated at different moisture content (MC) (3 %, 8 %, 13 %, 15 %, 20 % and 30 %). In vitro starch digestibility was determined and related to the changes caused by MW treatment to flours' structure and thermal properties, which were influenced by MC. A reduction of 49 % and 65 % in the gelatinization enthalpy of samples treated at 20 % and 30 % MC denoted a partial gelatinization. A loss of granular crystallinity in treated samples was confirmed by XR-diffraction and FTIR, particularly at 15 %, 20 % and 30 % MC. MW promoted the formation of random-coil, α-helix and β-turn protein structure, and the disappearance of LF-β-sheet. Morphological differences were found between samples treated at 8 % MC (loss of polygonal structure, protein layer covering granules' surface and small holes) and 30 % MC (rounded and aggregated granules, covered with exudate amylose). In vitro starch digestibility revealed that samples treated at 20 % and 30 % MC showed 40 % and 47 % higher rapidly digestible starch, 48 % and 70 % lower slowly digestible starch and 90 % lower resistant starch than the untreated flour. Flour MC in MW-treatment allowed the modulation of structural and thermal characteristics of rice flour and consequently its starch hydrolysis rate.

Effect of Physical and Enzymatic Modifications on Composition, Properties and In Vitro Starch Digestibility of Sacred Lotus (Nelumbo nucifera) Seed Flour.

In this study, native lotus seed flour (N-LSF) was modified by different methods, namely, partial gelatinization (PG), heat–moisture treatment (HMT), or pullulanase treatment (EP). Their composition, functional properties, starch composition, and estimated glycemic index (eGI) were compared. PG contained similar protein, soluble dietary fiber, and insoluble dietary fiber contents to N-LSF, while those of HMT and EP differed from their native form. PG increased rapid digestible starch (RDS) but decreased resistant starch (RS); while HMT and EP increased amylose and RS contents to 34.57–39.23% and 86.99–92.52% total starch, respectively. Such differences led to the different pasting properties of the modified flours rather than PG, which was comparable to the native flour. HMT had limited pasting properties, while EP gave the highest viscosities upon pasting. The eGI of all samples could be classified as low (<50), except that of PG, which was in the medium range (60). It was plausible that lotus seed flour modified either with HMT or EP could be used as carbohydrate source for diabetes patients or health-conscious people.

Using buckwheat starch to produce slowly digestible biscuits with good palatability

AbstractBackground and ObjectiveDue to the rapid digestibility, cooked starch can cause a high postprandial blood glucose response (hyperglycemia), one of the risk factors for metabolic diseases, such as obesity and diabetes. The objective was to understand the properties of starch that provided slow digestibility in low‐moisture baked goods. Buckwheat (Fagopyrum esculentum Moench) starch was used to prepare biscuits with slowly digestible starch and was compared with wheat (Triticum aestivum) starch.FindingsBuckwheat starch had higher gelatinization temperature and smaller breakdown viscosity (in pasting curve) than wheat starch. Slower starch digestion rate and higher amount of undigested starch were observed when 60% (w/w) wheat flour in biscuits was substituted by buckwheat starch than by wheat starch. The biscuits containing buckwheat starch or wheat starch also showed a structure with lower firmness than the control biscuits.ConclusionBuckwheat starch was more resistant to gelatinization and breakage during baking, and thus was less susceptible to enzyme digestion in biscuits than wheat starch.Significance and NoveltyThis is the first study utilizing a starch having a normal amylose content without any modification, except partial gelatinization during baking, as a source of slowly digestible starch in biscuits. Buckwheat starch not only provided slow digestibility, but also improved the palatability of the biscuits, creating a smoother and less firm texture than those made using whole grain flour.

Chemical Components, Antioxidant Activity, and Glycemic Response Values of Purple Sweet Potato Products.

Purple sweet potato is a source of starch with high potential to be developed as a functional food. It can be boiled and consumed as a snack or processed into intermediate goods such as flour. The flour can then be modified through partial gelatinization and followed by a retrogradation process to produce resistant starch-rich purple sweet potato flour. The study was aimed at obtaining the glycemic response values of purple sweet potato products, namely, boiled purple sweet potatoes (BSP), purple sweet potato noodles (SPN), and resistant starch-rich purple sweet potato noodles (RSPN). SPN was prepared from conventional purple sweet potato flour, whereas RSPN was made from resistant starch-rich purple sweet potato flour. Moreover, water, ash, protein, fat, and carbohydrate; total phenolic, anthocyanin, and resistant starch contents; and the rate of hydrolysis of starch were evaluated. Ten subjects were involved in the estimation of glycemic response determined by the area under the curve (AUC) of the blood glucose after consuming products. Glucose syrup was used as a reference. The glycemic response data were processed using ANOVA and further tested using LSD at p < 0.05. The results showed RSPN had the lowest glycemic index value if compared to BSP and SPN (58.7, 63.5, and 83.7) and fell under food with medium GI, but the differences were not statistically significant. RSPN and SPN were classified as medium GI; however, the process of partial gelatinization followed by retrogradation during the preparation of flour used for raw material in making RSPN has successfully maintained the total phenol and anthocyanin and increased resistant starch content of the noodle Processing of purple sweet potato flour into noodle lowered the GI category, and when the flour was partially gelatinized and retrograded, the noodle had more potentiality as a functional food due to their high total phenolic and anthocyanin content.

Effect of gelatinization degree on emulsification capacity of corn starch esterified with octenyl succinic acid

Normal corn starch (∼26% amylose content) was subjected to different degrees of extrusion-based pregelatinization (55, 75, and 95%) to improve the efficiency of octenyl succinic anhydride (OSA) esterification. The partial disruption of the native semi-crystalline structure was verified with X-ray diffraction and Fourier transform infrared analysis. It was found that partial gelatinization (pregelatinization) reduced the relative crystallinity, which is an effect that was magnified by OSA esterification. Polarized and scanning electron microscopies revealed gradual destruction of the starch granules, yielding a fraction of insoluble remnants for high gelatinization degrees. The emulsification index showed a marked increase of about 18% by single extrusion treatment. However, fully stable emulsions (emulsification index = 1.0) were obtained by dual extrusion-esterification treatment. The hardness of hydrogels was reduced by pregelatinization. Principal component analysis revealed that most starch characteristics were mutually interdependent and that the impact of gelatinization degree was independent of the impact of OSA esterification.