Annealing improves paste viscosity and stability of starch

Enhanced gelling property and freeze-thaw stability of potato, tapioca and corn starches modified by mild heating in aqueous ethanol solution

BACKGROUND

Physically modified starches can be classified as natural ingredients on food labels and clean label products. Thus, the market demand for physically modified starch is increasing. Potato, tapioca and corn starches were physically modified by mild heat treatment in an alcoholic solution to enhance their gelling property and freeze-thaw stability.

RESULTS

During mild heating of starch suspension (40% w/w) in 10% ethanol solution at the onset gelatinization temperature, granular swelling of starch occurred, followed by amylose leaching with medication of the surface structure of the starch granules. All treated starches exhibited increased gelatinization and pasting temperatures and decreased breakdown for pasting as a result of improved stability against shear and heat. The treated starches had higher hardness, cohesiveness and springiness of gel than the respective native starches, and these gel properties were more pronounced in potato starch than in tapioca and corn starches. The treated starches showed substantially reduced gel syneresis during freeze-thawing.

CONCLUSION

Physical modification of starch by mild heat treatment in an alcoholic solution substantially improved its gelation ability and freeze-thaw stability. © 2024 Society of Chemical Industry.

Effect of extrusion using plasma-activated water on the structural, physicochemical, antioxidant and in vitro digestive properties of yam flour

The synergistic effects of plasma-activated water (PAW) and twin-screw extrusion (TSE) on the structural, physicochemical, antioxidant, and digestive properties of yam flour (YF) were studied. Compared to common TSE, PAW-TSE reduced the protein, starch, and polyphenol contents, swelling power, and gel property of YF, while PAW-TSE enhanced the flavonoid content, whiteness index, solubility, and antioxidant property of YF. Moreover, the results of structural characterization and differential scanning calorimetry indicated that the long-range or short-range ordering, and gelatinization enthalpy of starch in YF were reduced after PAW-TSE, while the structure ordering of proteins in YF increased. Furthermore, the in vitro digestibility results demonstrated a reduction in the rate of enzymatic hydrolysis, coupled with an increase in total contents of slowly digestible and resistant starch after PAW-TSE. It should be noted that TSE using PAW prepared by a longer plasma treatment resulted in a more significant improvement effect on YF.

Effect of Oat Beta-Glucan on Physicochemical Properties and Digestibility of Fava Bean Starch

The current research examined the impact of different concentrations of oat beta-glucan (OG) on the in vitro digestibility of fava bean starch (FS). Our pasting analysis demonstrated that OG effectively decreased the viscosity and regrowth of FS, suppressing its in situ regrowth while enhancing the in vitro pasting temperature. Moreover, OG markedly diminished amylose leaching and minimized the particle size of the pasted starch. Rheological and textural evaluations demonstrated that OG markedly diminished the viscoelasticity of the starch and softened the gel strength of the composite system. Structural analysis revealed that hydrogen bonding is the primary interaction in the FS-OG system, indicating that OG interacts with amylose through hydrogen bonding, thereby delaying starch pasting and enhancing the gelatinization characteristics of FS gels. Notably, the incorporation of OG resulted in a reduction in the levels of rapidly digestible starch (RDS) and slowly digestible starch (SDS) in FS, accompanied by a notable increase in resistant starch (RS) content, from 21.30% to 31.82%. This study offers crucial insights for the application of OG in starch-based functional foods.

Recrystallized resistant starch by encapsulation with konjac glucomannan: Structural changes, digestibility, and its effect on glucose response and short-term satiety in mice

The effects of the structure and digestibility of konjac glucomannan (KGM)-recrystallized resistant starch complex (KRS3) on the glycemic response and short-term satiety in mice were investigated. KRS3 samples were prepared by recrystallized debranched starch (RS3) at 50 °C, and then combined with KGM. The RS3 and KRS3 samples displayed an A-type pattern and maintained peak temperature values above 110 °C. With an increase in KGM, the swelling power and apparent viscosity of KRS3 increased. The results of in vitro and in vivo digestion revealed that KRS3 with a resistant starch content ranging from 69.4 % to 78.8 % could effectively maintain postprandial blood glucose levels. KRS3, particularly with 0.5 % KGM, slowed gastric emptying of mice from 82.7 % to 36.6 % and intestinal propulsion rate from 60.9 % to 35.3 %, resulting in strong satiety. RS3 combined with KGM could serve as a new approach to develop RS3 based foods with low glycemic responses and high-satiety.

Effect of extrusion on the formation, structure and properties of yam starch-gallic acid complexes

This paper investigated the effects of twin-screw extrusion treatment on the formation, structure and properties of yam starch-gallic acid complexes. Yam starch and gallic acid were extruded. The microstructure, gelatinization characteristics, and rheological properties of the samples were determined. The microstructure of extruded yam starch-gallic acid complexes presented a rough granular morphology, low swelling, and high solubility. The X-ray diffraction analysis showed that the extruded yam starch-gallic acid complexes exhibited A + V-type crystalline structure. Fourier transform infrared spectroscopy results showed that the extrusion treatment could destroy the internal orderly structure of yam starch, and the addition of gallic acid could further reduce its molecular orderliness. Differential scanning calorimetry analysis showed a decrease in the enthalpy of gelatinization of the sample. Dynamic rheological analysis showed that the storage modulus and loss modulus of the extruded yam starch-gallic acid complexes were significantly reduced, exhibiting a weak gel system. The results of viscosity showed that extrusion synergistic gallic acid reduced the peak viscosity and setback value of starch. In addition, extrusion treatment had an inhibitory effect on the digestibility of yam starch, and enhanced the interaction of gallic acid with yam starch or hydrolytic enzymes. Therefore, extrusion synergistic gallic acid has improved the structure and properties of yam starch-related products, which can provide new directions and new ideas for the development of yam starch.

Pasting properties of A- and B-type wheat starch granules and annealed starches in relation to swelling and solubility

Wheat starch contains two distinct groups of granules, A-type and B-type, which have different compositions and properties. The aim of this study was to investigate the differences in pasting properties of A- and B-type wheat starch granules and their annealed starches, and to relate them to swelling properties and solubility. A- and B-type wheat starch granules were fractionated. The differences in pasting properties between A- and B-type wheat starch granules depended on starch solids content. The A-type starch had a higher pasting viscosity at ≥8 % solids content, but the trend was reversed at a lower solids content (5 %). This cross-over phenomenon in the pasting viscosity can be explained because A-type wheat starch granules have more starch molecules leached out, while swelled less at high temperatures and are probably more rigid than B-type wheat starch granules. This is the first study to show the cross-over in the pasting viscosity-starch concentration between A-type and B-type wheat starches and that B-type wheat starch has higher pasting viscosity than A-type at a low solids content. When annealed in warm water, both annealed A- and B-type wheat starch granules had higher pasting viscosities than untreated counterparts by altering the swelling of starch.

Properties of pyrodextrinization corn starch and their inhibitory effect on the retrogradation of fresh rice noodles

This study was aimed to investigate the properties of pyrodextrins under different preparation conditions and the effects of pyrodextrins on the retrogradation of fresh rice noodles. Pyrodextrins were made by heating corn starch with and without lactic acid at 180 °C ranging from 1 to 6 h. The molecular weights of pyrodextrins gradually decreased, whereas the branching degree increased and the chain length shrank with the prolongation of heating time. The changes of acid-heat-treated pyrodextrins were more pronounced than those of dry-heat-treated pyrodextrins under the same treatment time. The acid-heat-treated pyrodextrins displayed higher water solubility and lower viscosity, suggesting that they could no longer gel. These results suggest that starch retrogradation could be limited by pyrodextrins, especially acid-heat-treated pyrodextrins. Then, the pyrodextrins were added to fresh rice noodles and the eating and cooking qualities were examined during storage. After 35 days of storage, the pyrodextrin with acid heating at 180 °C for 4 h showed the most effective inhibition on starch retrogradation and was suitable for fresh rice noodles as an anti-retrogradation agent. The study might supply new perspectives on restraining starch retrogradation and promoting the fresh rice noodle industry.

Understanding the multi-scale structure, physicochemical and digestive properties of extruded yam starch with plasma-activated water

In this study, the synergistic effect of plasma-activated water (PAW) combined with twin-screw extrusion (TSE) on multi-scale structure, physicochemical and digestive properties of yam starch (YS) was studied. PAW-TSE resulted in higher amylose content in YS than TSE alone. Compared with single TSE, the relative crystallinity, short-range ordered degree, and gelatinization enthalpy of YS were increased by PAW-TSE according to the results of X-ray diffraction, Fourier transform infrared, Raman spectroscopy, and differential scanning calorimetry. Furthermore, rapid viscosity and dynamic rheological analysis showed that the peak and breakdown viscosity of PAW-TSE treated YS paste were considerably reduced, and the storage modulus and loss modulus were significantly increased, indicating that the gel strength and thermal stability were improved. In addition, the resistant starch (RS) content of YS treated by PAW-TSE increased from 6.04 % to 21.21 %. Notably, the effect of PAW-TSE on YS enhanced with the preparation time of PAW increased. Finally, correlation analysis indicated that the characteristic indexes of PAW had a significant impact on the long or short-range ordered structure, thermal properties, and in vitro digestibility of YS during extrusion. Therefore, PAW-TSE, as an emerging dual modification technology, will greatly expand the application of extrusion technology.

Hydrothermal treatments of starch impact reaction patterns during subsequent chemical derivatization

Differences in derivatization patterns (using a fluorescent reagent, fluorescein isothiocyanate) of wheat, pea, and potato starches between native granular (NAT) starches and their respective annealed (ANN) and heat-moisture treated (HMT) starches were investigated to reveal structural changes associated with starch hydrothermal treatments. Size-exclusion chromatography with fluorescence and refractive index detection assessed the reactivity of amylose (AM), intermediate chains (IM1 and IM2), and amylopectin branch chains (AP1, AP2, and AP3) within the different starches. Shifts in X-ray diffraction patterns of HMT starches and in the gelatinization properties of both ANN and HMT starches confirmed molecular rearrangement. The reaction homogeneity (wheat and pea) and the overall extent of reaction (pea and potato) increased for HMT starches compared to other starches. The lower reactivities of IM2 chains (HMT starch) and AP3 chains (ANN starch) relative to NAT starches, indicated their involvement in molecular rearrangements and improved double helical order. IM2 and AP branch chains in ANN pea starch also were less reacted than NAT starch chains, suggesting their co-crystallization. Molecular rearrangements in ANN and HMT starches led to altered swelling and pasting viscosities. Thus, changes in the relative crystallinity of individual starch branch chains induced by hydrothermal processing impact the final physical properties.

Effects of Continuous and Cycled Annealing on the Physicochemical Properties and Digestibility of Water Caltrop Starch

The effects of treatment time of continuous annealing (ANN) and cycle numbers of cycled ANN on the structural, physicochemical, and digestive properties of water caltrop starch were studied under 70% moisture at 65 °C. It was found that continuous and cycled ANN have no significant effects on the morphology of starch granules. However, the relative crystallinity and content of resistant starch increased pronouncedly, possibly due to crystalline perfection, which also led to the rise in gelatinization temperature and the narrowed gelatinization temperature range of starch. The treatment time in continuous ANN generally showed a pronounced effect on the rheological properties of water caltrop starch. During pasting, the breakdown viscosity and setback viscosity of all treatment decreased, implying that ANN modified starch was less susceptible to the condition in heating and continuous shearing, and less likely to cause short-term retrogradation. In contrast, peak viscosity decreased with increasing treatment time of continuous ANN, indicating crystalline perfection restricted the swelling of starch granules and viscosity development during pasting process, which was consistent with the results of steady and dynamic rheological evaluation. All ANN-modified samples showed pseudoplastic behavior with weak gel viscoelastic characteristic. Under a total annealing time of 96 h, the pasting and rheological properties of water caltrop starch were essentially less affected by annealing cycle numbers. However, multistage ANN showed stronger resistance to enzyme hydrolysis.

Glutenin-gliadin ratio changes combining heat-moisture treatment significantly influences the in vitro digestibility of starch in recombinant wheat flours

This study aimed to investigate the effect of heat-moisture treatment (HMT) on the in vitro digestibility of recombinant wheat flours characterizing by gluten proteins differ in glutenin-gliadin ratio. Compared with the untreated flours in our previous study, HMT improved the digestion resistance of starch in flours with different glutenin-gliadin ratios. For the HMT strong-gluten flour, the proportional increase of glutenin led to an excessively strong and fragile gluten network that unstable under HMT, which weakened the wrapping of gluten network around starch granules and reduced the long- and short-range order of starch, resulting in the conversion of resistant starch (RS) and slowly digestible starch (SDS) to rapidly digestible starch (RDS); however, the quantitative increase of gliadin induced the conversion of SDS to RS due to the enhanced protein-starch interactions as well as the improved long- and short-range order of starch during HMT. For the HMT weak-gluten flour, the changes of glutenin-gliadin ratio aggravated the broken of protein network and starch granules during HMT, thus improving the starch digestibility in varying degrees. In conclusion, the relative crystallinity of starch mainly affected the content of resistant starch, while the content of slowly digestible starch was more influenced by protein-starch interactions.

Hydrothermal processes and simultaneous enzymatic hydrolysis in the production of modified cassava starches with porous-surfaces

The amylolytic action of α-amylase and amyloglucosidase has been directly implemented in native cassava starches for the formation of cassava microporous granules with unsatisfactory results, however, its incidence in hydrothermally treated granules has never been evaluated. The effect of hydrothermal processes and simultaneous enzymatic hydrolysis on the physicochemical, morphological and structural properties of native cassava starch was evaluated. Native cassava starch presented a rigid, smooth surface, and was exempt from porosities, whereas hydrothermal processes altered the semicrystalline order and increasing the size and number of pores and increasing the size (4.11 ± 0.09 nm) and volume of pores (0.82 ± 0.00 cm3/g × 10-3). The hydrothermal action followed by enzymatic processes with α-amylase and amyloglucosidase, augmented the processes of internal degradation (endo-erosion) and pore widening (exo-erosion), improving the hydrophilic properties compared to the hydrothermal treatment. Likewise, the hydrothermally process followed by enzymatic hydrolysis for 24 h (HPS + EMS-24) increased the degradation of the amorphous lamellae, consistent with a significant decrease in amylose content. This same dual treatment increased the pore size at 17.68 ± 0.13 nm relative to the native counterpart; therefore, they are considered an effective method in the development of modified cassava starches with porous surfaces.

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.

Removing starch granule-associated surface lipids affects structure of heat-moisture treated hull-less barley starch

The effects of starch granule-associated surface lipids removal on hull-less barley starch structure formed by heat-moisture treatment were investigated. Removing surface lipids made the peak at 2θ of 13^° disappear and resulted in higher lamellar peak intensity after harsh treatment and a lower reduction in mass fractal dimension (from 2.49 to 2.43) and radius of gyration (from 24.3 to 24.0) when temperature increased from 100 to 120 °C at 20 % moisture. Treatment at 25 % moisture and 120 °C decreased relative crystallinity (from 15.73 % to 7.43 %) and Gaussian peak area (from 646.7 to 137.7) of native starch, and decreased relative crystallinity (from 14.24 % to 12.56 %) and Gaussian peak area (from 604.1 to 539.6) for starch without surface lipids. Different trends of change in lamellar thickness, linear crystallinity, peak temperatures, and enthalpy of gelatinization were observed among modified starches with increasing temperature and/or moisture content. These results demonstrate that removing surface lipids changes structure of heat-moisture treated starch.

The Influence of Temperature Changes on the Rice Starch Structure and Digestive Characteristics: One and Two-Step Annealing

This study investigated the effects of annealing on the structural and physicochemical properties of rice starch below the onset temperature (To) by 5 °C and 15 °C. The results revealed that annealing improved the gelatinization temperature of rice starch, decreased the swelling power, solubility, and paste viscosity of rice starch, and had no significant effects on the morphological structure and crystal configuration of rice starch. In one-step annealing, the annealing temperature of 60 °C is more conducive to the rearrangement of starch molecules, so its crystallinity, short-range ordered structure, and gelatinization temperature are higher than at 50 °C; however, its RDS, SDS, and RS contents will be increased. During the two-step annealing treatment, the temperature change is not conducive to the molecular chain rearrangement and to the formation of perfect crystalline structure, which increases the sensitivity of enzymes to starch, so the RDS content of starch increases significantly, while the RS content decreases.

Thermal properties of different types of starch: A review

Starch is present in high amount in various cereals, fruits and roots & tubers which finds major application in industry. Commercially, starch is rarely consumed or processed in its native form, thus modification of starch is widely used method for increasing its application and process stability. Due to the high demand for starch in industrial applications, researchers were driven to hunt for new sources of starch, including modification of starch through green processing. Thermal properties are significant reference parameters for evaluating the quality of starch when it comes to cooking and processing. Modification of starches affects the thermal properties, which are widely studied using Differential scanning calorimeter or Thermogravimetric analysis. It could lead to a better understanding of starch's thermal properties including factors influencing and expand its commercial applications as a thickener, extender, fat replacer, etc. in more depth. Therefore, the review presents the classification of starches, factors influencing the thermal properties, measurement methods and thermal properties of starch in its native and modified form. Further, this review concludes that extensive research on the thermal properties of new sources of starch, as well as modified starch, is required to boost thermal stability and extend industrial applications.

Physical, Chemical and Biochemical Modification Approaches of Potato (Peel) Constituents for Bio-Based Food Packaging Concepts: A Review

Potatoes are grown in large quantities and are mainly used as food or animal feed. Potato processing generates a large amount of side streams, which are currently low value by-products of the potato processing industry. The utilization of the potato peel side stream and other potato residues is also becoming increasingly important from a sustainability point of view. Individual constituents of potato peel or complete potato tubers can for instance be used for application in other products such as bio-based food packaging. Prior using constituents for specific applications, their properties and characteristics need to be known and understood. This article extensively reviews the scientific literature about physical, chemical, and biochemical modification of potato constituents. Besides short explanations about the modification techniques, extensive summaries of the results from scientific articles are outlined focusing on the main constituents of potatoes, namely potato starch and potato protein. The effects of the different modification techniques are qualitatively interpreted in tables to obtain a condensed overview about the influence of different modification techniques on the potato constituents. Overall, this article provides an up-to-date and comprehensive overview of the possibilities and implications of modifying potato components for potential further valorization in, e.g., bio-based food packaging.

Effect of annealing using plasma-activated water on the structure and properties of wheat flour

In this study, wheat flour (WF) was modified by annealing (ANN) using plasma-activated water (PAW) for the first time. Compared with WF and DW-WF, the results of scanning electron microscopy (SEM) and particle-size analysis showed that the granule structure of wheat starch in PAW-WF was slightly damaged, and the particle size of PAW-WF was significantly reduced. The results of X-ray diffraction and Fourier transforming infrared spectroscopy indicated that PAW-ANN could reduce the long-range and short-range order degrees of wheat starch and change the secondary structure of the protein in WF, in which the content of random coils and α-helices was significantly increased. In addition, the analysis of solubility, viscosity, and dynamic rheological properties showed that PAW-ANN improved the solubility and gel properties of WF and decreased its viscosity properties and short-term regeneration. PAW-ANN, as a green modification technology, has the potential for further application in WF modification, as well as in the production of flour products.

Ultrasound-chilling assisted annealing treatment to produce a lower glycemic index of white rice grains with different amylose content

White rice samples, Chai-Nat1 (CN1) and Jasmin rice (KDML105), were treated with the ultrasound-chilling (UC) and combined with annealing treatments (UC + ANN 45, UC + ANN50, and UC + ANN55). Their physicochemical properties and in vitro glycemic index of rice samples were analyzed. UC + ANN treatments presented pasting temperature, gelatinization temperature and crystallinity increased whereas the glycemic index of both rice samples was decreased as compared to its native. Especially, UC + ANN55 treated rice produced the lowest glycemic index and starch hydrolysis. Moreover, UC + ANN treated CN1 rice exhibited delayed gelatinization temperature, increased gelatinization enthalpy, and decreased glycemic index than KDML105 rice. In addition, Pearson's correlation presented that UC + ANN and amylose content had a highly negative correlation with the glycemic index at p < 0.0.1. The result exhibited that UC followed by ANN show an effective way to modify starch granules with delayed starch hydrolysis reduced glycemic index and properties depending on annealing temperature and rice cultivar.

Understanding the Structure, Thermal, Pasting, and Rheological Properties of Potato and Pea Starches Affected by Annealing Using Plasma-Activated Water

In this research, annealing (ANN) using plasma-activated water (PAW) was first employed to modify potato and pea starches. Compared with the conventional ANN using distilled water (DW), the granular morphology of two starches was not significantly affected by PAW-ANN. The results of X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy showed that PAW-ANN could reduce the long and short-range ordered structure of potato starch while improving the long and short-range ordered structure of pea starch. Differential scanning calorimetry (DSC) analysis indicated that PAW-ANN lowered the gelatinization enthalpy of potato starch and increased the gelatinization enthalpy of pea starch. The analysis of viscosity and dynamic rheological characteristics illustrated that PAW-ANN reduced the peak viscosity and improved the gel strength of starch pastes. PAW-ANN represents a novel modification method for modifying the structure, reducing the viscosity, improving the gel strength of starch, and is very promising for applying in starch-based hydrogels and food additives.

Starch structure and nutritional functionality - Past revelations and future prospects

Starch exists naturally as insoluble semi-crystalline granules assembled by amylose and amylopectin. Acknowledging the pioneers, we have reviewed the major accomplishments in the area of starch structure from the early 18th century and further established the relation of starch structure to nutritional functionality. Although a huge array of work is reported in the area, the review identified that some features of starch are still not fully understood and needs further elucidation. With the rise of diet-related diseases, it has never been more important to understand starch structure and use that knowledge to improve the nutritional value of the world's principal energy source.

Methods for characterizing the structure of starch in relation to its applications: a comprehensive review

Starch is a major part of the human diet and an important material for industrial utilization. The structure of starch granules is the subject of intensive research because it determines functionality, and hence suitability for specific applications. Starch granules are made up of a hierarchy of complex structural elements, from lamellae and amorphous regions to blocklets, growth rings and granules, which increase in scale from nanometers to microns. The complexity of these native structures changes with the processing of starch-rich ingredients into foods and other products. This review aims to provide a comprehensive review of analytical methods developed to characterize structure of starch granules, and their applications in analyzing the changes in starch structure as a result of processing, with particular consideration of the poorly understood short-range ordered structures in amorphous regions of granules.

Physicochemical Properties and Digestion Resistance of Acetylated Starch Obtained from Annealed Starch

One of the examples of physical starch modifications is the retention of a starch suspension in water having a temperature slightly lower than the pasting temperature (annealing). The aim of this study was to investigate the effect of the annealing process performed at various temperatures as the first stage of starch modification. The annealed starch preparations were then esterified using acetic acid anhydride. Finally, the annealed and acetylated starch preparations were determined for their properties. The annealing of starch before acetylation triggered changes in the properties of the modified preparations. It contributed to a higher degree of starch substitution with acetic acid residues and to the increased swelling power of starch. Both these properties were also affected by the annealing temperature. The highest resistance to amylolysis was found in the case of the starch preparation annealed at 53.5 °C and acetylated. The double modification involving annealing and acetylation processes increased the onset and end pasting temperatures compared to the acetylation alone. Similar observations were made for the consistency coefficient and yield point.

Physicochemical property changes and aroma differences of fermented yellow pea flours: role of Lactobacilli and fermentation time

The aim of this study was to evaluate the physicochemical properties and aroma differences of yellow pea flours fermented by five lactic acid bacteria (LAB) strains including two Lactiplantibacillus, two Lactobacillus, and one Lacticaseibacillus with different fermentation time. The cell population and the pH of pea flour slurry, as well as the proximate chemical composition, amino acids, thermal and pasting properties, surface morphology, and aromatic differences of fermented flours were characterized. The cell population of all strains except for Lactobacillus helveticus was observed to reach above 107 CFU mL-1 after 24 h of fermentation. The fermentation with Lactobacilli resulted in the increase of amino acids and ash contents, and the reduction of fat content. Rapid viscosity analysis indicated that short time (18 h) fermentation with L. helveticus drastically improved the pasting properties of the flours by facilitating starch granule expansion. The aromatic compounds of the fermented yellow pea flours were highly reliant on the strains and fermentation time. The untargeted metabolomics analysis with the aid of multivariate data analysis can discriminate the aroma differences among the fermented yellow pea flours. L. acidophilus fermentation led to the production of three aromatic compounds which may contribute to an improved aromatic profile.

Removal of starch granule associated proteins alters the physicochemical properties of annealed rice starches

The effect of removal of starch granule associated proteins (SGAPs), annealing and dual-treatment on physicochemical properties of three rice starches with different amylose content (AC) was investigated. SGAPs removal reduced stability of starch granules, thus increasing amylose leaching, swelling power, solubility, and pseudoplasticity of Qiuguang (15.6% AC) and Luhui (22.1% AC) rice starches, decreasing pseudoplasticity of Yangfunuo (1.56% AC) starch, and decreasing T_o, T_p, and T_c, pasting viscosity and storage modulus of all three rice starches. Annealing decreased amylose leaching of the three starches, and pasting properties, pseudoplastic and storage modulus of Yangfunuo starch, but increased swelling power of the three starches, ΔH and T_o of Qiuguang starch, and pasting properties and pseudoplasticity of Qiuguang and Luhui starches. The effect of dual-treatment was generally the sum of effect of SGAPs removal and annealing treatment. But an interaction effect of the dual-treatment was observed for some parameters. The effect of annealing was closely related to the variety and composition of the starch.

Effect of Drying Methods on Properties of Potato Flour and Noodles Made with Potato Flour

This work investigated the impact of three drying methods on structural and functional properties of potato flour (PF), as well as the quality characteristics of fresh noodles made from wheat-potato flours. The results indicated that ethanol drying (ED) and oven drying (OD) had small effects on the properties of starch in potato flour, however, freeze drying (FD) caused some pores and channels on the starch granules and disruption of the long- and short-range ordered structure of starch. The maximum addition of potato flour in fresh noodles was 40% for FD-PF and 50% for both ED-PF and OD-PF. With increasing addition of potato flour in noodles, the L* (lightness) values of noodles decreased gradually, while the a* (redness) and the b* (yellowness) values, as well as the hardness and springiness values of fresh potato noodles increased. This study clearly showed that drying methods have different effects on the properties of potato flour, and in turn the quality of fresh noodles made with potato flour.

The Annealing of Acetylated Potato Starch with Various Substitution Degrees

This study aimed to determine the effect of "annealing" acetylated potato starch with a homogenous granule size and various degrees of substitution on the thermal pasting characteristics (DSC), resistance to amylases, rheology of the prepared pastes, swelling power and dynamics of drug release. A fraction of large granules was separated from native starch with the sedimentation method and acetylated with various doses of acetic anhydride (6.5, 13.0 or 26.0 26 cm3/100 g starch). The starch acetates were then annealed at slightly lower temperatures than their pasting temperatures. The annealing process caused an almost twofold increase in the resistance to amylolysis and a threefold increase in the swelling power of the modified starch preparations. The heat of phase transition decreased almost two times and the range of starch pasting temperatures over two times, but the pasting temperature itself increased by ca. 10 °C. The 40 g/100 g addition of the modified starch preparation decreased the rate of drug release from a hydrogel by ca. one-fourth compared to the control sample.

Effect of annealing and heat-moisture pretreatments on the oil absorption of normal maize starch during frying

The impacts of two hydrothermal pretreatments, annealing (ANN) and heat moisture treatment (HMT), on oil-absorption by normal maize starch (NMS) during frying were investigated using low-field nuclear magnetic resonance (LF-NMR). The structural organizations of the fried samples were also evaluated using SEM, XRD, ATR-FTIR, and DSC, respectively. Both hydrothermal pretreatments significantly reduced the total oil content in the starch after frying, with the magnitude of the effect depending on the treatment conditions used. SEM showed that the pretreated fried starch granules preserved more of their original morphology. XRD, FTIR, and DSC showed that both pretreatments preserved more of the short-range double helices and long-range organizations within the orthorhombic crystalline structure for NMS during frying. The promoting effect of ANN/HMT on the interactions of starch molecules and the rearrangement of double helices were hypothesized to be responsible for the increased thermal stability of starch granules in the present work. As a result, fried starch pretreated by ANN/HMT were more organized and more compact than fried NMS, thus inhibiting oil absorption during frying.

Characterisation and utilisation of nano-reduced starch from underutilised cereals for delivery of folic acid through human GI tract

Ball milling offers green approach for size reduction of starch granules to nano scale size. In this research work, the starch from two underutilised cereal varieties viz. foxtail starch (FS) and sorghum starch (SS) were milled to achieve the desired nanometric range with mean particle diameter of 467.98 and 271.12 nm for nano foxtail (FSN) and nano sorghum starch (SSN), which were highly stable as revealed by zeta potential analysis. Functional attributes like solubility, swelling index, apparent amylose content, emulsifying and pasting properties were evaluated. Scanning electron microscopy (SEM) clearly revealed damaged starch granules produed by the process of milling. X-ray diffraction (XRD) displayed decrease in crystallinity upon milling to 16.08% (SSN) and 18.56% (FSN) and disappearance of some peaks. Attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) also revealed reduced crystallinity as confirmed by the decreased absorbance ratio of 1047/1022 cm-1 in nano starch particles. Rheological analysis displayed shear thinning behaviour of nano starch samples as evaluated using Herschel-bulkely model and Power law. The nano starch samples exhibited comparatively low thermal gelatinisation temperatures as compared to native counter particles. Moreover, the nano-encapsulated starch samples offered more resistance to in-vitro digestion and showed control release of folic acid at target sites.