Indigestible pyrodextrins prepared from corn starch in the presence of glacial acetic acid

Molecular Structure and Properties of Resistant Dextrins from Potato Starch Prepared by Microwave Heating

The dextrinization of potato starch was performed using a sophisticated single-mode microwave reactor with temperature and pressure control using 10 cycles of heating with stirring between cycles. Microwave power from 150 to 250 W, a cycle time from 15 to 25 s, and two types of vessels with different internal diameters (12 and 24 mm) and therefore different thicknesses of the heated starch layer were used in order to estimate the impact of vessel size used for microwave dextrinization. The characteristics of resistant dextrins (RD) including solubility in water, total dietary fiber (TDF) content, color parameters, the share of various glycosidic bonds, and pasting and rheological properties were carried out. The applied conditions allowed us to obtain RDs with water solubility up to 74% at 20 °C, as well as TDF content up to 47%, with a predominance of low-molecular-weight soluble fiber fraction, with increased content of non-starch glycosidic bonds, negligible viscosity, and a slightly beige color. The geometry of the reaction vessel influenced the properties of dextrins obtained under the same heating power, time, and repetition amounts. Among the conditions used, the most favorable conditions were heating 10 times for 20 s at 200 W in a 10 mL vessel and the least favorable were 15 s cycles.

Functionalization Methods of Starch and Its Derivatives: From Old Limitations to New Possibilities

It has long been known that starch as a raw material is of strategic importance for meeting primarily the nutritional needs of people around the world. Year by year, the demand not only for traditional but also for functional food based on starch and its derivatives is growing. Problems with the availability of petrochemical raw materials, as well as environmental problems with the recycling of post-production waste, make non-food industries also increasingly interested in this biopolymer. Its supporters will point out countless advantages such as wide availability, renewability, and biodegradability. Opponents, in turn, will argue that they will not balance the problems with its processing and storage and poor functional properties. Hence, the race to find new methods to improve starch properties towards multifunctionality is still ongoing. For these reasons, in the presented review, referring to the structure and physicochemical properties of starch, attempts were made to highlight not only the current limitations in its processing but also new possibilities. Attention was paid to progress in the non-selective and selective functionalization of starch to obtain materials with the greatest application potential in the food (resistant starch, dextrins, and maltodextrins) and/or in the non-food industries (hydrophobic and oxidized 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.

Characterization, health benefits, and food applications of enzymatic digestion- resistant dextrin: A review

Resistant dextrin or resistant maltodextrin (RD), a short-chain glucose polymer that is highly resistant to hydrolysis by human digestive enzymes, has shown broad developmental prospects in the food industry and has gained substantial attention owing to its lack of undesirable effects on the sensory features of food or the digestive system. However, comprehensive fundamental and application information on RD and how RD improves anti-diabetes and obesity have not yet been received. Therefore, the characterization, health benefits and application of RD in various fields are summarized and discussed in the current study. Typically, RD is prepared by the acid thermal method and possesses excellent physicochemical properties, including low viscosity, high solubility, storage stability, and low retro-gradation, which are correlated with its low molecular weight (Mw) and non-digestible glycosidic linkages. In contrast, RD prepared by the simultaneous debranching and crystallization method has low solubility and high crystallinity. The ingestion of RD can positively affect metabolic diseases (diabetes and obesity) in animals and humans by producing short-chain fatty acids (SCFAs), and facilitating the inflammatory response. Moreover, RD has been widely used in the beverage, dairy products, and dessert industries due to its nutritional value and textural properties without unacceptable quality loss. More studies are required to further explore RD application potential in the food industry and its role in the management of different chronic metabolic disorders.

Effect of Continuous and Discontinuous Microwave-Assisted Heating on Starch-Derived Dietary Fiber Production

Dietary fiber can be obtained by dextrinization, which occurs while heating starch in the presence of acids. During dextrinization, depolymerization, transglycosylation, and repolymerization occur, leading to structural changes responsible for increasing resistance to starch enzymatic digestion. The conventional dextrinization time can be decreased by using microwave-assisted heating. The main objective of this study was to obtain dietary fiber from acidified potato starch using continuous and discontinuous microwave-assisted heating and to investigate the structure and physicochemical properties of the resulting dextrins. Dextrins were characterized by water solubility, dextrose equivalent, and color parameters (L* a* b*). Total dietary fiber content was measured according to the AOAC 2009.01 method. Structural and morphological changes were determined by means of SEM, XRD, DSC, and GC-MS analyses. Microwave-assisted dextrinization of potato starch led to light yellow to brownish products with increased solubility in water and diminished crystallinity and gelatinization enthalpy. Dextrinization products contained glycosidic linkages and branched residues not present in native starch, indicative of its conversion into dietary fiber. Thus, microwave-assisted heating can induce structural changes in potato starch, originating products with a high level of dietary fiber content.

Structural comparisons of pyrodextrins during thermal degradation process: The role of hydrochloric acid

Hydrochloric acid (HCl) is widely used to prepare pyrodextrins, especially the water-soluble pyrodextrin. In this study, the structural difference between pyrodextrins as affected by HCl is compared by characterizing the molecular size, chain-length distributions (CLDs), crystallinity, and solubility. It is found that: 1) dry heating of starch granules without HCl mainly degrades long-amylose chains while slightly affects amylopectin branches; 2) the presence of HCl during dry heating decreases the degree of polymerization (DP) range of amylose chains upon degradation from DP ~ 833-1267 to DP ~ 206-432, suggesting that the presence of HCl accelerates the breakdown of long-amylose chains; 3) both pyroconversion processes have slight effects on A-(DP ~ 6-12) and B₁- chains (DP ~ 12-24), which might explain the retained granular and crystalline structure during the process. This study could improve the understanding of the role of HCl in affecting the structure and property during pyroconversion of native starch.

Ultrasound-assisted modification of rutin to nanocrystals and its application in barley starch pyrodextrinization

Ultrasound technology offers low cost and efficiency in nanodrug production and therefore was selected to investigate the formation of rutin nanocrystals, and its incorporation in barley starch pyrodextrin. Ultrasonication of rutin (600 W in water, citric acid and NaCl media) was carried out prior to rutin-barley starch pyrodextrinization (90 °C, 1 h). The ultrasound treated rutin (UTR) nanocrystal strands had <820 nm in diameter but shorter lengths from treatments at 27 and 36 kJ/cm³ (47 °C) compared to 3.9 and 7.0 kJ/cm³ (86 °C). All UTR showed color changes from yellow (control) to green and greenish-yellow. Also, thermal analysis indicated that UTR-citric acid had two polymorphs identified by melting peaks at 129.97 °C and 145.04 °C and an earlier decomposition at 179.47 °C compared to 244 °C (control). Rutin/UTR had no significant influence on the production of maltooligosaccharides (18-75 mg/mL of dextrin syrup). Ultrasonication enhanced rutin properties for oral delivery.

Pyrodextrinization of yam (Dioscorea sp.) starch isolated from tubers grown in Brazil and physicochemical characterization of yellow pyrodextrins

This study optimizes the pyrodextrinization of yam (Dioscorea sp.) starch isolated from tubers grown in Brazil to produce a yellow pyrodextrin with the lowest enzymatically available starch (AS) content and color difference (ΔE) index. At 140 °C (fixed heating temperature), the effects of acid concentration (0.65 - 2.99 g of HCl/kg of starch) and incubation time (53 - 307 min) on the response variables were evaluated using a response surface methodology. Some physicochemical characteristics were also determined on pyrodextrins. Both factors negatively affected the AS content, although positively influenced the ΔE (P < 0.05). The yellow pyrodextrin produced with 1.82 g/kg and heating for 307 min, presented physicochemical properties similar to the commercial pyrodextrins from potato starch, with 46.6 % of AS, 24.5 of ΔE, high solubility and very low viscosity. The pyrodextrinization caused a decrease of 30 - 54 % in AS content (P < 0.05), making these yam pyrodextrins a promising material for water-soluble and very low viscous dietary fiber.

In-depth study of the changes in properties and molecular structure of cassava starch during resistant dextrin preparation

Physical, chemical and thermal properties, as well as molecular structure of cassava-based resistant dextrins prepared under different dextrinization conditions (0.04-0.10% HCl, 100-120 °C, 60-180 min) were determined. Increasing acid concentration, temperature and heating time resulted in the products with darker color, higher solubility, reducing sugar content, total dietary fiber and proportion of high molecular weight fiber fraction. An endothermic peak at 45-70 °C, having enthalpy of 1.66-2.14 J/g, was found from the samples processed under mild conditions (0.04-0.08% HCl, 100 °C, 60 min). However, harsher dextrinization conditions eliminated this endotherm. Dextrinization led to 1000-fold decrease in weight-average molecular weight (M_w) of the products, comparing to the native starch. Stronger processing conditions yielded the resistant dextrins with slightly higher M_w but composing of shorter branched chains. During dextrinization, hydrolysis was a predominant step, while transglucosidation and repolymerization played key roles in modifying molecular structure and properties, especially dietary fiber content, of resistant dextrins.