Physicochemical properties and digestibility of hydrothermally treated waxy rice starch

Encapsulation of Fatty Acids Using Linear Dextrin from Waxy Potato Starch: Effect of Debranching Time and Degree of Unsaturation

This study investigates the effects of the debranching time of waxy potato starch using pullulanase and recrystallization on particle morphology, debranching degree, and crystal structure. The results demonstrated that after gelatinization and debranching, the surface of the starch crystals became rough and uneven due to hydrolysis, with most particles showing a fragmented surface. The crystalline state was not significantly changed with debranching time. X-ray diffraction analysis revealed no significant differences in the patterns of recrystallized linear dextrin (LD) after various debranching times. Notably, the short-range ordered structure of LD after debranching and recrystallization was more organized than that of the original or gelatinized starch. Additionally, polarized light microscopy showed that the birefringent pattern disappeared as a result of debranching and recrystallization, indicating the breakdown of particle structure, although the overall particle morphology did not change significantly with varying debranching times. Furthermore, linear dextrin derived from starch debranched for 6 h (with pullulanase at 15 μg/g) successfully embedded stearic acid, oleic acid, and linoleic acid, forming a VI-type starch-fatty acid complex.

Morphological, physicochemical, and pasting properties of pre-gelatinized starch prepared by high-pressure homogenizer: A comparative study on starches from different resources

Pre-gelatinized starch, a physically modified starch known for its ability to swell in cold water, has wide applications across various industries. This study assesses the feasibility of high-pressure homogenization (HPH) in producing pre-gelatinized starches and compares their morphological, physicochemical, and pasting properties from different sources. Starches from eleven sources, including mung bean, pea, wheat, sweet potato, cassava, corn, non-waxy rice, waxy rice, chickpea, lentil, and chestnut, were processed using HPH at 150 MPa for three cycles. The resulting pre-gelatinized starch granules exhibited disrupted surface structures, increased water absorption and solubility, decreased crystallinity, and altered gelatinization temperatures. Results showed that waxy rice pre-gelatinized starch had the highest degree of pre-gelatinization (90.27%) and water absorption index (61.95%), while chestnut pre-gelatinized starch had the highest water solubility index (21.58%) and lentil pre-gelatinized starch demonstrated the highest gel strength (2178.00 g). X-ray diffraction analysis revealed a significant reduction in crystallinity, with values ranging from 13.96% to 18.29%. Additionally, the study observed variations in pasting properties, with cassava pre-gelatinized starch exhibiting the highest peak viscosity (5458 cP), trough viscosity (3864 cP), and final viscosity (6536 cP). These findings indicate that HPH is an effective method for producing pre-gelatinized starch with enhanced functional properties, enriching the scientific understanding of pre-gelatinized starches from different sources and promoting their application in the food industry and other sectors.

Effects of moisture regulation and heat treatment synergy on structural properties and digestibility of jackfruit seed starch

To investigate the impact of moisture regulation and heat treatment synergy on the structural properties and digestibility of jackfruit seed starch (JSS), starch samples underwent heat-moisture treatment (HMT) and annealing treatment (ANN) with varying moisture content (10-30 % for HMT at 120 °C, and 50-90 % for ANN at 40 °C). The physicochemical properties and in vitro digestibility of modified-JSS were systematically investigated. Results showed that the birefringence intensity of HMT-JSS decreased at high moisture levels but remained unchanged for HMT-JSS and ANN-JSS at low moisture levels. As moisture content increased for HMT and ANN, the amylose content and relative crystallinity increased and then slightly decreased. The gelatinization temperatures increased while enthalpy and viscosity declined. At high moisture content, the infrared absorbance ratio of 1047 cm-1/1022 cm-1 decreased on HMT but increased on ANN. Resistant starch (RS) contents of both HMT-JSS and ANN-JSS were increased at appropriate moisture levels (10-15 % for HMT, 50-80 % for ANN), but decreased with excessive moisture. Besides, these changes were more pronounced on HMT than ANN. Correlation analysis showed that the RS was significantly affected by the short-range ordered structure during HMT and ANN. These results revealed that hydrothermal treatment efficiently modified the structure properties and digestibility of JSS.

Effects of Stir-Frying and Heat-Moisture Treatment on the Physicochemical Quality of Glutinous Rice Flour for Making Taopian, a Traditional Chinese Pastry

Taopian is a traditional Chinese pastry made from cooked glutinous rice flour. The effects of heat-moisture treatment (110 °C, 4 h; moisture contents 12-36%, w/w) on the preparation of cooked glutinous rice flour and taopian made from it were compared with the traditional method of stir-frying (180 °C, 30 s). The color of heat-moisture-treated (HMT) flours was darker. HMT flours exhibited a larger mean particle size (89.5-124 μm) and a greater relative crystallinity of starch (23.08-42.92%) and mass fractal dimension (1.77-2.28). The flours exhibited water activity in the range of 0.589-0.631. Although the oil-binding capacity of HMT flours was largely comparable to that of stir-fried flours, HMT flours exhibited a lower water absorption index. Accordingly, the taopian produced with HMT flours exhibited a lower brightness, accompanied by a stronger reddening and yellowing. In addition, more firmly bound water was observed in the taopian produced with HMT flour. The taopian made with HMT flour with a moisture content of 24% exhibited moderate hardness, adhesiveness and cohesiveness and received the highest score for overall acceptability (6.80). These results may be helpful to improve the quality of taopian by applying heat-moisture treatment in the preparation of cooked glutinous rice flour.

Quantification of resistant starch content in rice after hydrothermal treatments using terahertz spectroscopy

Since hydrothermal treatments can enhance resistant starch (RS) content in rice and provide health benefits when consumed, a less laborious and non-destructive method to determine RS content is needed. Terahertz (THz) spectroscopy is hypothesized as a suitable method to quantify RS content in rice after hydrothermal treatment with its sensitivity for the intermolecular forces increase in the formation of RS. In this study, we first used the traditional in vitro hydrolysis method to determine the content of RS in rice. Then, the potential of starch absorbance peaks to quantify RS content after three commonly used hydrothermal methods, soaking, mild heat-moisture treatment, and parboiling, was investigated. The second derivative intensities of the peak at 9.0, 10.5, 12.1, and 13.1 THz were confirmed as being correlated with RS content and showed the high accuracy to predict RS content in samples (R2 > 0.96). Our results indicate the RS content of hydrothermally treated rice can be accurately quantified using these peaks.

Influence of different baking temperatures of red kojic rice on the physicochemical properties, antioxidant capacity, and functional components of red starter wine

BACKGROUND

To improve the quality of red starter wine, this study explored the effects of baking red kojic rice at varying temperatures on the physicochemical characteristics of red starter wine. Baking was predicated on understanding crucial enzyme activities and starch granule structure of red kojic rice at 75, 95, and 105 °C, leading to the production of three red starter wine variants (BHQW1, BHQW2, and BHQW3).

RESULTS

The results revealed an increased alcohol (increase 0.50%), total sugar (increase 0.14 g L-1 ), and total acid (increase 0.54 g L-1 ) content in red starter wine fermented using baked red kojic rice compared with the control group (wine fermented with unbaked rice, HQW). Furthermore, both the 105 °C baked red kojic rice and its resulting BHQW3 demonstrated significantly higher red color values than HQW (increase 2.03 U g-1 and 0.15 U mL-1 respectively). The highest lovastatin content was presented in red kojic rice baked at 105 °C and its corresponding fermented wine (1420.63 ± 507.9 μg g-1 and 3368.87 ± 228.16 μg L-1 respectively). Additionally, BHQW groups displayed higher total flavonoids and phenols content than HQW. Regarding antioxidant capacity, all BHQW groups showed stronger overall antioxidant capacity than HQW. The determination of volatile components revealed the highest content of volatile compounds in BHQW2 (2621.19 ± 548.24 μg L-1 ) and significantly higher volatile esters in BHQW1 (254.46 ± 16.63 μg L-1 ). Moreover, 16 volatile compounds were identified only in BHQW groups, including isoamyl caprylate, 2-ethylhexyl alcohol, and benzaldehyde.

CONCLUSION

Our findings suggested that the baking technique of red kojic rice could enhance the quality of red starter wine through enhancing antioxidant properties, increasing functional components, and enriching volatile flavor compounds, thus providing a foundation for new techniques in red starter wine production. © 2023 Society of Chemical Industry.

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.

Characteristics of rice starches modified by single and dual heat moisture and osmotic pressure treatments

The effect of osmotic pressure treatment (OPT), heat moisture treatment (HMT), and their dual combination as HMT-OPT and OPT-HMT on functional and pasting properties, gel texture, crystallinity, thermal, morphological, and rheological properties, and in vitro digestibility of modified starches were investigated. HMT was done with 29 % moisture at 111 °C for 45 min while OPT was performed at 117 °C for 35 min with saturated sodium sulphate solution. All modifications increased amylose content, improved pasting stability, and reduced swelling power and solubility. Dual modifications caused higher morphological changes than single modified starches. HMT and OPT increased pasting temperature, setback and final viscosity while decreased peak viscosity and breakdown, whereas HMT-OPT and OPT-HMT reduced all pasting parameters except pasting temperature. 1047/1022 and 995/1022 ratios and relative crystallinity decreased. V-type polymorphs were formed, and gelatinization temperature range increased with lower gelatinization enthalpy. Starch gel elasticity, RS and SDS content were enhanced to a greater extent after HMT-OPT and OPT-HMT. HMT as a single and dual form with OPT showed prominent effect on pasting, thermal, crystalline, and rheological properties. Application of HMT, OPT and dual modified starches with improved functionalities may be targeted for suitable food applications such as noodles.

Resistant starch formation mechanism of amylosucrase-modified starches with crystalline structure enhanced by hydrothermal treatment

The aim of this study was to reveal the underlying mechanism contributing towards the formation of resistant starch (RS) in amylosucrase-modified starches with crystalline structure enhanced by hydrothermal treatment. The branch chains of waxy corn starch were continuously elongated by amylosucrase, and the retrogradation of elongated starches with weight-average chain length (CL_w¯) of 27.0-37.6 yielded B-type retrograded starches (MSs) with crystallinity increasing from 33.1 % (MS-5) to 41.4 % (MS-30). Increasing the starch crystallinity improved the content of RS from 6.7 % of MS-5 to be as much as 41.0 % of MS-30. During the hydrothermal treatment, MS-5 with CL_w¯ of 27.0 favored the B → A allomorphic transition, leading to the decreased starch digestibility. Moreover, the hydrothermal treatment facilitated the assembly of double helices to increase starch crystallinity, which further increased the content of RS. The findings of the present study may assist the preparation of functional starches with controllable digestibility.

Electron beam irradiation modification of ultra-high pressure treated broad bean starch: Improvement of multi-scale structure and functional properties

To investigate the synergistic effect of electron beam irradiation (EBI) on the ultra-high pressure (UHP) modification of broad bean starch, various pressures (200, 400, 600 MPa) combined with different irradiation doses (3, 6, 12 kGy) were used to modify the structure-properties of broad bean starch in this study. The results showed that both UHP and EBI induced a reduction of amylopectin molecular weight (Mw) and depolymerization of long chains, caused the loss of short-range ordered structure and imperfection of crystal structure, and improved starch viscosity, solubility and enzyme sensitivity. Furthermore, the applied pressure causes changes in starch granule structure, upon which EBI promotes further degradation and depolymerization of starch by affecting the crystalline and amorphous regions. Hence, appropriate doses of EBI treatment can impart more desirable processing properties to UHP-modified starches, and EBI can be used as a promising way to promote starch modification further.

A Review on Isolation, Characterization, Modification, and Applications of Proso Millet Starch

Proso millet starch (PMS) as an unconventional and underutilized millet starch is becoming increasingly popular worldwide due to its health-promoting properties. This review summarizes research progress in the isolation, characterization, modification, and applications of PMS. PMS can be isolated from proso millet grains by acidic, alkaline, or enzymatic extraction. PMS exhibits typical A-type polymorphic diffraction patterns and shows polygonal and spherical granular structures with a granule size of 0.3-17 µm. PMS is modified by chemical, physical, and biological methods. The native and modified PMS are analyzed for swelling power, solubility, pasting properties, thermal properties, retrogradation, freeze-thaw stability, and in vitro digestibility. The improved physicochemical, structural, and functional properties and digestibility of modified PMS are discussed in terms of their suitability for specific applications. The potential applications of native and modified PMS in food and nonfood products are presented. Future prospects for research and commercial use of PMS in the food industry are also highlighted.

Characteristics of physically modified starches

Starch is an abundant natural, non-toxic, biodegradable polymer. Due to its low price, it is used for various purposes in various fields such as the cosmetic, paper, and construction industries as well as the food industry. Due to recent consumer interest in clean label materials, physically modified starch is attracting attention. Manufacturing methods of physically modified starch include pregelatinization, hydrothermal treatment such as heat moisture treatment and annealing, hydrostatic pressure treatment, ultrasonic treatment, milling, and freezing. In this study, toward development of clean label materials, manufacturing methods and characteristics of physically modified starches were discussed.

Effect of heat-moisture treatment on the physicochemical properties and digestibility of proso millet flour and starch

Proso millet flour (PMF) and starch (PMS) were subjected to heat-moisture treatment (HMT) at 25 % moisture content and 110 °C for 4 h. The effects of HMT on physicochemical and structural properties and in vitro digestibility of PMF and PMS were analyzed. After HMT, SEM showed aggregation and damage to the surface of starch granules, while CLSM showed proteins wrapped around the granules. The amylopectin chain length distribution (CLD) remained unchanged in PMF and PMS after HMT, indicating intact covalent bonds between glucose units. HMT decreased the swelling power, solubility, viscosity of the paste, and gelatinization enthalpy and increased the pasting temperature and gelatinization temperature of PMF and PMS. HMT changed the XRD pattern of PMF from A to A + V type starches, whereas that of PMS remained unchanged. FTIR study showed an increase in the degree of short-range molecular order of PMF and PMS after HMT. In vitro digestibility evaluation showed that the rapidly (RDS) and slowly digestible starch (SDS) contents of PMF and PMS increased, whereas the resistant starch (RS) content decreased after HMT. HMT flour and starch have suitable properties for use in a wide range of food products, from canned to frozen, as well as non-food products.

Effects of enhanced starch-xanthan gum synergism on their physicochemical properties, functionalities, structural characteristics, and digestibility

The limited and unstable interactions between potato starch (PS) and xanthan gum (XG) by simple mixing (SM) lead it difficult to induce substantial changes in starchy products. Structural unwinding and rearrangement of PS and XG by critical melting and freeze-thawing (CMFT) were used to promote PS/XG synergism, and the physicochemical, functionalities, and structural properties were investigated. Compared to "Native" and SM, CMFT promoted the formation of large clusters with a rough granular surface and wrapped by a matrix composed of released soluble starches and XG (SEM), thus making the composite more compact to thermal processes, such as the significantly decreased WSI and SP, and increased the melting temperatures. The enhanced synergism of PS/XG after CMFT effectively decreased the breakdown viscosity from ~3600 (Native) to ~300 mPa·s and increased the final viscosity from ~2800 (Native) to ~4800. CMFT significantly increased the functional properties of PS/XG composite, including water/oil absorptions and resistant starch content. CMFT caused the partial melting and loss of large packaged structures in starch (XRD, FTIR, and NMR), and the melting and the loss of crystalline structure controlled at approximately 20 % and 30 %, respectively, are the most effective for promoting PS/XG interaction.

Superheated steam processing of cereals and cereal products: A review

The concept of superheated steam (SS) was proposed over a century ago and has been widely studied as a drying method. SS processing of cereals and cereal products has been extensively studied in recent years for its advantages of higher drying rates above the inversion temperature, oxygen-free environment, energy conservation, and environmental protection. This review provides a brief introduction to the history, principles, and classification of SS. The applications of SS processing in the drying, enzymatic inactivation, sterilization, mycotoxin degradation, roasting, and cooking of cereals and cereal products are summarized and discussed. Moreover, the effects of SS processing on the physicochemical properties of cereals and the qualities of cereal foods are reviewed and discussed. The applications of SS for cereal processing and its effects on cereal properties have been extensively studied; however, issues such as the browning of cereal foods, thermal damage of starch, protein denaturation, and nutrition loss have not been comprehensively studied. Therefore, further studies are required to better understand the mechanism of the quality changes caused by SS processing and to expand the fields of application of SS in the cereal processing industry. This review enhances the understanding of SS processing and presents theoretical suggestions for promoting SS processing to improve the safety and quality of cereals and cereal products.

Optimisation of the techno-functional and thermal properties of heat moisture treated Bambara groundnut starch using response surface methodology

This work optimised the techno-functional and thermal properties of heat moisture treated Bambara groundnut starch (BGS). A central composite rotatable design (Design-Expert software v8.0.1.0) comprising two independent factors of temperature and time was used. Extracted BGS were subjected to heat-moisture treatment (HMT) at 80-120 °C for 30-90 min at different moisture levels of 15% (HMT 15-BGS), 25% (HMT 25-BGS) and 35% (HMT 35-BGS). The optimum HMT conditions for BGS were found to be 80 °C for 30 min (HMT 15), 105.74 °C for 30 min (HMT 25), and 113.16 °C for 30 min (HMT 35). The desirability values of the obtained optimum conditions were 0.63 (HMT 15) and 1.00 (HMT 25 and 35). In HMT 35-BGS, water absorption capacity was significantly affected by the quadratic effect of temperature and time. In contrast, solubility was significantly affected by the linear effect of time and the quadratic effect of temperature. Temperature and treatment time had no significant effect (p ≥ 0.05) on the differential scanning calorimetry thermal properties of HMT 15, 25 and 35-BGS. Scanning electron micrographs of optimised BGS showed round and oval-shaped starch granules ranging from 4.2 to 4.7 mm (width) and 10 μm for length. Unmodified and optimised HMT-BGS showed characteristic FTIR bands linked with common starches. All BGS samples displayed multiple vibrations in the region below 1000 cm^-1 due to the skeletal vibrations of the glucose pyranose ring.

Citric acid esterified Glutinous Assam bora rice starch enhances disintegration and dissolution efficiency of model drug

The current work was designed to study the starch's physicochemical attributes, tablet disintegration and dissolution efficiency and its derivatives obtained from the glutinous Assam bora rice (G-ABR) variety of Assam, Northeast India. Starch was isolated by a simple protein denaturation method, and a starch derivative was prepared through citric acid modification. G-ABRS and citrated G-ABRS were characterized through FTIR, DSC, XRD and SEM. The rate of consolidation, consolidation index, angle of internal friction, packing rearrangement and cohesive properties were determined to investigate their applications as functional excipients in pharmaceutical industries. G-ABRS and citrated G-ABRS exhibited better packing rearrangement and cohesive properties than standard corn starch. Furthermore, immediate release of API from the tablet compact was observed when the starch concentration increased from 1 to 5 %, indicating facilitation of the tablet compact disintegration. Therefore, G-ABRS and citrated G-ABRS are potentially functional and sustainable materials for pharmaceutical industries.

Effects of Heat-Moisture Treatment on the Digestibility and Physicochemical Properties of Waxy and Normal Potato Starches

Heat-moisture treatment (HMT) is a safe, environmentally friendly starch modification method that reduces the digestibility of starch and changes its physicochemical properties while maintaining its granular state. Normal potato starch (NPS) and waxy potato starch (WPS) were subjected to HMT at different temperatures. Due to erosion by high-temperature water vapor, both starches developed indentations and cracks after HMT. Changes were not evident in the amylose content since the interaction between the starch molecules affected the complexation of amylose and iodine. HMT increased pasting temperature of NPS from 64.37 °C to 91.25 °C and WPS from 68.06 °C to 74.44 °C. The peak viscosity of NPS decreased from 504 BU to 105 BU and WPS decreased from 384 BU to 334 BU. The crystallinity of NPS decreased from 33.0% to 24.6% and WPS decreased from 35.4% to 29.5%. While the enthalpy values of the NPS declined from 15.74 (J/g) to 6.75 (J/g) and WPS declined from 14.68 (J/g) to 8.31 (J/g) at 120 °C. The solubility and swelling power of NPS decreased while that of WPS increased at 95 °C. Due to the lack of amylose in WPS, at the same HMT processing temperature, the reduction in peak viscosity of treated WPS compared to that of native starch was smaller than that of NPS. The resistant starch (RS) content of NPS after HMT at 120 °C was 73.0%. The slowly digestible starch (SDS) content of WPS after HMT at 110 °C was 37.6%.

A Mini Review of Physicochemical Properties of Starch and Flour by Using Hydrothermal Treatment

Starch and flour from various plants have been widely used for sundry applications, especially in the food and chemical industries. However, native starch and flour have several weaknesses, especially in functional, pasting, and physicochemical properties. The quality of native starch and flour can be improved by a modification process. The type of modification that is safe, easy, and efficient is physical modification using hydrothermal treatment techniques, including heat moisture treatment (HMT) and annealing (ANN). This review discusses the hydrothermal modifications of starch and flour, especially from various tubers and cereals. The discussion is mainly on its effect on five parameters, namely functional properties, morphology, pasting properties, crystallinity, and thermal properties. Modification of HMT and ANN, in general, can improve the functional properties, causing cracking of the granule surface, stable viscosity to heat, increasing crystallinity, and increasing gelatinization temperature. However, some modifications of starch and flour by HMT and ANN had no effect on several parameters or even had the opposite effect. The summary of the various studies reviewed can be a reference for the development of hydrothermal-modified starch and flour applications for various industries.

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.

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.

Effect of baking technique for rice wine production and the characteristics of baked rice wine

BACKGROUND

Driven by the requirement to reduce the emission of wastewater in the brewing process, it is necessary to improve and innovate the fermentation technology of Chinese rice wine. In this study, the baking technique used to brew rice wine was explored.

RESULTS

Rice wine was brewed based on baked glutinous rice undergoing different high-temperature stages, designated as baked rice wine (BRW1, BRW2 and BRW3). X-ray diffraction and Fourier transform infrared analysis revealed that baking treatment under 110 °C 0.5 h + 170 °C 30 min relatively changed the crystal properties and short-range molecular order of starch. Compared with the traditional rice wine (RW) from steamed rice, the alcohol content in BRWs was nearly twice that of RW, especially in BRW3. The contents of protein, ascorbic acid and total phenols in BRWs were significantly higher than that in RW. Besides, BRWs presented more abundance in the contents of volatile compounds, free amino acids and certain organic acids, including volatile esters and alcohols and 17 amino acids, which would give rice wine a pleasant aroma and a more comprehensive taste. Furthermore, analysis of the antioxidant capacity indicated a functional difference between RW and BRWs.

CONCLUSION

It was feasible to produce rice wine using baked rice. The baking method allowed for several advantages, including the improvement of alcohol yield, fermentation efficiency, new typicality and stronger antioxidant capacity. This work is expected to provide a foundation for related research. © 2021 Society of Chemical Industry.

Influence of waxy proteins on wheat resistant starch formation, molecular structure and physicochemical properties

This study investigated the influence of wheat waxy proteins on type III resistant starch (RS3) formation, molecular structure and physicochemical properties. Waxy deletions led to a significant increase in B- and C-type starch granules, particle size of RS3, and slowly digesting starch content, and a decrease in content of amylose and RS3. X-ray powder diffraction and Fourier-transform infrared spectroscopy analyses revealed high relative crystallinity and long-range (1047/1022 cm-1, IR1) and low short-range (1022/995, IR2) crystalline structures of RS3 in waxy wheat, which suggests that waxy deletions could produce a more ordered crystalline structure and fewer amorphous regions in RS3 crystals. Further laser confocal microscopy Raman spectroscopy analysis found that waxy deletions significantly increased the full width at half maximum and intensity of the bands at 480 cm-1, as well as leading to more ordered RS3 crystals. These changes in molecular structure resulted in improved physicochemical properties of RS3.

Modulating Structure and Properties of Glutinous Rice Flour and Its Dumpling Products by Annealing

In this study, annealed glutinous rice flour treated under different conditions (ANN1, ANN2 and ANN3) were prepared. The structure as well as physicochemical characteristics of the flour and its dumpling products were investigated. The crystallinity of the annealed flour samples increased, while the hydration ability decreased. The content of bound water raised, and immobilized water as well as the freezing enthalpy value decreased for the fast-frozen dumplings made from annealed flour samples. It showed that annealed treatment could reduce the formation of large ice crystals, thus decrease the cracking of fast-frozen dumplings. The freezing enthalpy value of annealed dumplings decreased which was conducive to protect the structure and quality of products. The boiled dumplings made of annealed flour had better eating quality as demonstrated by the increase in the transmittance of the soup. It indicated that moderate annealed glutinous rice flour ANN2 had optimal physicochemical properties to make high quality dumplings. This study would pave the way for further study of the annealing glutinous rice flour and provide theoretical guidance for the application of annealing treatment in starchy food product.

Linear Dextrin as Potential Insulin Delivery System: Effect of Degree of Polymerization on the Physicochemical Properties of Linear Dextrin-Insulin Inclusion Complexes

In the current study, linear dextrin (LD) was prepared using waxy potato starch debranched with pullulanase, which has attracted immense interest in the food, pharmaceutical, and cosmetic industries as a versatile ingredient. Various LDs were separated on the basis of their differential solubility in aqueous/ethanol solutions of different volumetric ratios. Three LD products—LD Fabrications with 40% ethanol (F-40); LD Fabrications with 50% ethanol (F-50); and LD Fabrications with 60%, 70%, and 80% ethanol (F-M)—were obtained with an average degree of polymerization (DP) values of 31.44, 21.84, and 16.10, respectively. The results of Fourier transform infrared spectroscopy (FT-IR) analysis revealed that the reaction mainly involved hydrogen bonding and a hydrophobic interaction between LD and insulin in the process of inclusion complex formation. X-ray diffraction (XRD) results indicated that insulin was encapsulated in LD. The results of circular dichroism (CD) showed that the changes in the secondary structure of insulin were negligible during the release from the inclusion complexes. The order of encapsulation capacity is as follows: the complex composed of F-M and insulin (F-M-INS) > the complex composed of LD and insulin (LD-INS) > the complex composed of F-50 and insulin (F-50-INS) > and the complex composed of F-40 and insulin (F-40-INS). F-M-INS inclusion complexes showed a better effect on reducing the release of insulin in gastric juice and promoting the release of insulin in intestinal juice and blood plasma than LD-INS.

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.

Influence of whey protein isolate on pasting, thermal, and structural characteristics of oat starch

We investigated the effects of different concentrations of whey protein isolate (WPI) on oat starch characteristics in terms of pasting, thermal, and structural properties. The pasting properties of the starch showed that hot paste viscosity increased with the addition of WPI in the system, and relative breakdown decreased. Thermal analysis showed a significant effect of WPI on oat starch by increasing the peak temperature of differential scanning calorimeter endotherms. The X-ray diffraction and Fourier transform infrared spectroscopy studies revealed that WPI increased the ordered structuration of starch paste, as evident by an increase in relative crystallinity; in addition, a decrease in infrared bands at 1,024 cm^-1 and 1,080 cm^-1 suggested decreased gelatinization of oat starch granules. Overall, WPI at different concentrations affected the oat starch gelatinization properties.

Thermal, pasting and structural studies of oat starch-caseinate interactions

The effects of different concentrations of calcium caseinate (CaCn) on pasting, thermal and structural properties of oat starch were investigated. The effect of CaCn on oat starch was highly dependent on the concentration of CaCn in the mixtures. Characterizations of pasting properties revealed that breakdown, final and setback viscosities increased at high relative contents of CaCn (>50%, w/w), while setback and stability ratio were decreased. Thermal analysis showed an increase in gelatinization temperature and a decrease in enthalpy change. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) suggested significant effects of CaCn on oat starch gelatinization. Based on XRD results, a decreasing trend was observed on the relative crystallinity of the starch-protein mixtures containing high levels of CaCn (e.g. 50% and 75% relative CaCn contents). Increases in FT-IR bands at 1024 cm^-1 and 1152 cm^-1 suggested an increase in amorphous structuration of the mentioned starch-protein mixtures.

Quantification of Starch Order in Physically Modified Rice Flours Using Small-Angle X-ray Scattering (SAXS) and Fourier Transform Infrared (FT-IR) Spectroscopy

The purpose of this study was to understand the ordered structure of starch in rice flour based on a physical modification with non-heating, milling, and water sorption through the structural evaluation of rice flour using small-angle X-ray scattering (SAXS) and infrared spectroscopy within the 4000-100 cm^-1 region. The SAXS pattern of the samples with low moisture contents subjected to milling yield a band within the 0.4-0.9 nm^-1 of the q range owing to a lamellar repeat of starch with an ordered structure in rice flour. We proposed an order parameter using the intensity of the SAXS band to quantify the order structure of starch in rice flour, and the true density was negatively correlated with the order parameter. Infrared band at 990 cm^-1 in COH bending mode applied to the hydroxyl group of C6 shifted to a low wavenumber corresponding to the order parameter. A linear correlation was found between the order parameter and the 990 cm^-1 and band at 861 cm^-1 owing to COC symmetrical stretching of glycoside bond and CH₂ deformation of the glucose unit of starch, 572, 472, and 436 cm^-1, owing to the pyranose ring in the glucose unit of starch. The identified infrared bands are effective for quantifying the ordered structure of starch at the lamellar level. When subjected to water sorption, the band position at 990 cm^-1 shifted to a higher wavenumber above a water activity of 0.7. This result revealed that the water-induced transition of glass to rubber of starch in rice flour can be clearly evaluated through infrared spectroscopy using the band at 990 cm^-1. In addition, the band at 861 cm^-1 also shifted to a higher wavenumber, whereas those at 572 and 436 cm^-1 did not show a significant shift. These results indicate that water sorption slightly affects the internal structure and may mainly affect the surface of starch.

Physical modification on the in vitro digestibility of Tartary buckwheat starch: Repeated retrogradation under isothermal and non-isothermal conditions

The effects of repeated retrogradation (RR, range from 1 to 3 times) at different temperatures (4 °C; 4/25 °C, with a 24 h interval; 25 °C) on the in vitro digestibility and structures of Tartary buckwheat starch (TS) were investigated in this study. Results demonstrated that TS treated by RR for 1 time under 4/25 °C contained the maximum content of slowly digestible starch (SDS, 35.25%); TS treated by RR for 3 times under 25 °C contained the maximum content of resistant starch (RS, 54.92%). As the increase of RR cycle times, the value of relative crystallinity, the ratios of 1047/1022 cm^-1 and 995/1022 cm^-1 increased, the starch pore wall thickened, and more smooth fragments appeared (observed by scanning electron microscope), while the value of melting temperature range trended to decrease. The crystallization type of TS changed from type "A" to a mixture of "B + V" after retrogradation treatment. Pearson correlation analysis revealed that the content of rapidly digestible starch (RDS) was negatively correlated with the ratio of 995/1022 cm^-1, transition temperatures, and enthalpy (P < 0.05). These results would supply a potential method for the preparation of starch with slow-digesting properties, also improve the utilization and expand the application of TS.

Millet starch: A review

The demand for millets and their products is becoming popular globally due to their various health-promoting properties. The major constituent of the millet is its starch which contributes about 70% of total millet grain and decides the quality of millet-based food products. The application of starch for various purposes is dependent upon its physicochemical, structural, and functional properties. A native starch does not possess all the required properties for a specific use. However, product-specific properties can be achieved by modifying the structure of starches. Information deficit on millet starch has undermined its potential use in new food product design. The objective of this review is to examine the chemical composition, characterization, structural chemistry, digestibility, hydrolysis, and modification techniques of the millet starches. The review paper also discusses the various applications of native and modified starches in the food industry.

Synergetic modification of waxy maize starch by dual-enzyme to lower the in vitro digestibility through modulating molecular structure and malto-oligosaccharide content

Cyclodextrinase (CDase) and cyclodextrin glucosyltransferase (CGTase) were synergistically used to provide a novel enzymatic method in lowing in vitro digestibility of waxy maize starch. The molecular structure, malto-oligosaccharide composition, and digestibility properties of the generated products were investigated. The molecular weight was reduced to 0.3 × 10⁵ g/mol and 0.2 × 10⁵ g/mol by simultaneous and sequential treatment with CDase and CGTase, while the highest proportion of chains with degree of polymerization (DP) < 13 was obtained by simultaneous treatment. The resistant starch contents were increased to 27.5% and 36.9% by simultaneous and sequential treatments respectively. Dual-enzyme treatment significantly promoted the content of malto-oligosaccharides (MOSs) by hydrolyzing cyclodextrins from CGTase with CDase. However, the replacement of cyclodextrins by MOSs did not obviously influence the digestibility of the products. The starch digestion kinetics further revealed the hydrolysis pattern of these two enzymes on the starch hydrolysate. It was proved that the starch digestibility could be lowered by modulating the molecular structure and beneficial MOSs content by this dual-enzyme treatment.

Physicochemical properties and in vitro digestibility of hydrothermal treated Chinese yam (Dioscorea opposita Thunb.) starch and flour

The objective of this study was to investigate the effects of hydrothermal treatments (heat-moisture treatment (HMT) and annealing (ANN)) on the physicochemical properties and in vitro digestibility of yam starch and yam flour. Hydrothermal treatments decreased the pasting properties of yam starch and yam flour. Compared with yam starch, HMT significantly (p < 0.05) reduced the pasting viscosities of yam flour. Both HMT and ANN caused an increase of the gelatinization temperatures (T_o, T_p, and T_c) and a decrease of enthalpy (△H). The increasement in ratio of 1047/1022 cm^-1 and 995/1022 cm^-1 suggested that HMT and ANN resulted in an increase in short-range order. The crystalline pattern of all samples was still A-type, and HMT yam starch exhibited higher crystallinity (26.20%). The most significant inhibition of in vitro digestibility was found in HMT yam flour, with slowly digestible starch and resistant starch contents increasing by 3.73% and 4.40%, respectively. Hydrothermal treatments made the no-starch ingredients in yam flour agglomerate and adhere to starch granules. Confocal laser scanning microscopy showed that the starch being coated or embedded by protein was a possible reason for the differences in physicochemical properties and in vitro digestibility between yam starch and yam flour.

Deep Dive Into the Effects of Food Processing on Limiting Starch Digestibility and Lowering the Glycemic Response

During processing of cereal-based food products, starch undergoes dramatic changes. The objective of this work was to evaluate the impact of food processing on the starch digestibility profile of cereal-based foods using advanced imaging techniques, and to determine the effect of preserving starch in its native, slowly digestible form on its in vivo metabolic fate. Four different food products using different processing technologies were evaluated: extruded products, rusks, soft-baked cakes, and rotary-molded biscuits. Imaging techniques (X-ray diffraction, micro-X-ray microtomography, and electronic microscopy) were used to investigate changes in slowly digestible starch (SDS) structure that occurred during these different food processing technologies. For in vivo evaluation, International Standards for glycemic index (GI) methodology were applied on 12 healthy subjects. Rotary molding preserved starch in its intact form and resulted in the highest SDS content (28 g/100 g) and a significantly lower glycemic and insulinemic response, while the three other technologies resulted in SDS contents below 3 g/100 g. These low SDS values were due to greater disruption of the starch structure, which translated to a shift from a crystalline structure to an amorphous one. Modulation of postprandial glycemia, through starch digestibility modulation, is a meaningful target for the prevention of metabolic diseases.

Influence of moisture and amylose on the physicochemical properties of rice starch during heat treatment

Moisture and amylose are important factors affecting the quality of heat-treated starches. The amylose content in heat-treated rice starch increased as moisture content (MC) increased from 8% to 30%, but decreased at MC of 70%. With the increase of MC, the paste transmittance, gelatinization temperature, and digestibility of starch increased, whereas the swelling power and enthalpy decreased. The long- and short-range molecular order and the digestive properties of starch with MC ≤ 30% changed moderately, but high MC (70%) gelatinized the starch and drastically changed the physicochemical properties. High amylose content in rice starch led to low long- and short-range molecular order, swelling power, and gelatinization temperature, but increased resistant starch. The results indicated that 30% of MC separates effects of heat treatment of starch, where low MC (≤30%) and high amylose lowers digestibility, which is beneficial for diabetics, while high MC (>30%) promotes solubility and transparency.