Developing high resistant starch content rice noodles with superior quality: A method using modified rice flour and psyllium fiber.

The effects of high-resistant starch (RS) content rice flour, psyllium husk powder (PHP), and psyllium powder (PP) on the edible quality and starch digestibility of rice noodles were investigated in this study. High-RS rice noodles showed lower digestibility but poor edible quality. With the addition of PHP and PP, high-RS rice noodles' cooking and texture quality were improved significantly, especially the breakage rates, cooking losses, and chewiness (P < 0.05). Compared to traditional white rice noodle's estimated glycemic index (eGI) of 86.69, the eGI values for 5PHP-RN and 5PHP-2PP-RN were significantly decreased to 66.74 and 65.77, achieving a medium GI status (P < 0.05). This resulted from the high amylose and lipid content in the modified rice flour and psyllium, leading to increase of starch crystallinity. Besides, based on the analysis of Pearson's correlation, it can be found that PHP rich in insoluble dietary fiber (IDF) could improve high-RS noodle cooking and texture quality better, while PP rich in soluble dietary fiber (SDF) can further reduce the RDS content and its starch digestibility. Therefore, utilizing modified rice flour with an appropriate addition of PHP and PP can be considered an effective strategy for producing superior-quality lower glycemic index rice noodles.

The role of C18 fatty acids in improving the digestion and retrogradation properties of highland barley starch.

In this study, five C18 fatty acids (FA) with different numbers of double bonds and configurations including stearic acid (SA), oleic acid (OA), elaidic acid (EA), linoleic acid (LA), and α-linolenic acid (ALA), were selected to prepare highland barely starch (HBS)-FA complexes to modulate digestibility and elaborate the underlying mechanism. The results showed that HBS-SA had the highest complex index (34.18 %), relative crystallinity (17.62 %) and single helix content (25.78 %). Furthermore, the HBS-C18 FA complexes were formed by EA (C18 FA with monounsaturated bonds) that had the highest R1047/1022 (1.0509) and lowest full width at half-maximum (FWHM, 20.85), suggesting good short-range ordered structure. Moreover, all C18 FAs could form two kinds of V-type complexes with HBS, which can be confirmed by the results of CLSM and DSC measurements, and all of them showed significantly lower digestibility. HBS-EA possessed the highest resistant starch content (20.17 %), while HBS-SA had the highest slowly digestible starch content (26.61 %). In addition, the inhibition of HBS retrogradation by fatty acid addition was further proven, where HBS-SA gel firmness (37.80 g) and aging enthalpy value were the lowest, indicating the most effective. Overall, compounding with fatty acids, especially SA, could be used as a novel way to make functional foods based on HBS.

Effects of Four Highland Barley Proteins on the Pasting Properties and Short-Term Retrogradation of Highland Barley Starch.

This study evaluated the effects of four highland barley proteins (HBPs), namely, albumin, globulin, gliadin and glutenin, on the short-term retrogradation of highland barley starch (HBS). The findings reveal that HBPs could reduce the viscosity, storage modulus and hardness of HBS, with albumin and globulin showing more prominent effects. Furthermore, with the addition of HBPs, the loss tangent (tan δ) of HBS loss increased from 0.07 to 0.10, and the enthalpy of gelatinization decreased from 8.33 to 7.23. The degree of retrogradation (DR%) of HBS was 5.57%, and the DR% decreased by 26.65%, 38.78%, 11.67% and 20.29% with the addition of albumin, globulin, gliadin and glutenin, respectively. Moreover, the relative crystallinity (RC) and the double helix structures were inhibited with the HBPs' incorporation. Meanwhile, the HBPs also could inhibit water migration and improve the structure of HBS gels. In summary, HBPs could inhibit the retrogradation behavior of HBS, which provides new theoretical insights for the production studies of highland barley foods.

Effects of high-pressure microfluidization treatment on the structural, physiochemical properties of insoluble dietary fiber in highland barley bran.

High-pressure microfluidization treatment (HPMT) was performed on the insoluble dietary fiber (IDF) of highland barley bran (HBB), with conditions set at 60 MPa (IDF-60), 120 MPa (IDF-120), and two consecutive high-pressure treatments at 120 MPa (IDF-120-2), respectively. Then the particle size, structural, physicochemical and adsorption properties of different IDF samples were analyzed. After HPMT, the particle size of IDF samples gradiently decreased (p < 0.05), and part of IDF was transferred into soluble dietary fiber (SDF), accompanied by the decrease of hemicellulose and lignin content. In addition, the morphology of the IDF samples became more fragmented and wrinkled, and the two consecutive treatments at 120 MPa significantly damaged the crystalline structure of the IDF. Moreover, the adsorption capacities to water, oil, cholesterol, and NO2- were basically enhanced with the increase of treatment pressure and treatment number. The IDF-120-2 sample had the strongest water/oil-holding, swelling, and cholesterol trapping capacities, and the IDF-120 showed strongest NO2- trapping capacity (pH = 2). Through the correlation analysis, the adsorption capacities were positively to the particle size and SDF content, and negatively correlated with the specific surface area (SSA) and IDF content. The adsorption capacities of IDF for the four substances were positively correlated with each other.

Deeply analyzing dynamic fermentation of highland barley vinegar: Main physicochemical factors, key flavors, and dominate microorganisms.

Highland barley vinegar, as a solid-state fermentation-type vinegar emerged recently, is well-known in Qinghai-Tibet plateau area of China. This work aimed to explore the main physicochemical factors, key flavor volatile compounds, and dominate microorganisms of highland barley vinegar during fermentation. The results showed that the decrease trend of reducing sugar, pH and the increase trend of amino acid nitrogen were associated with the metabolism of dominate bacteria, especially Lactobacillus and Acetobacter. Totally, 35 volatile compounds mainly including 20 esters, 10 alcohols, 2 aldehydes, 1 ketone and 2 pyrazines and 7 organic acids were identified. Especially, isoamyl acetate, acetyl methyl carbinol, ethyl caprylate, 1,2-propanediol, 3-methyl-1-butanol and ethyl isovalerate with high odor activity values were confirmed as key aroma compounds. Meanwhile, the relative average abundance of bacteria at genus level decreased significantly as fermentation time goes on. Among these microbes, Lactobacillus were the dominate bacteria at alcohol fermentation stage, Lactobacillus and Acetobacter were dominate at acetic acid fermentation stage. Furthermore, the correlations between dominate bacteria and the key volatile compounds were revealed, which highlighted Lactobacillus and Acetobacter were significantly correlated with key volatile compounds (|r| > 0.5, P < 0.01). The fundings of this study provide insights into the flavor and assist to improve the production quality of highland barley vinegar.

Effect of continuous instant pressure drop treatment on the rheological properties and volatile flavor compounds of whole highland barley flour.

Continuous instant pressure drop (CIPD) treatment effectively reduces microbial contamination in whole highland barley flour (WHBF). Base on it, this study further investigated its effects on flour properties (especially rheological properties) and volatile compounds (VOCs) profile of WHBF, and compared it with that of ultraviolet-C (UV-C), ozone and hot air (HA) treatments. The results showed that the damaged starch content (6.0%) of CIPD-treated WHBF was increased, leading to a rough surface and partial aggregation of starch particle, thereby increasing the particle size (18.06 µm of D10, 261.46 µm of D50 and 534.44 µm of D90). Besides, CIPD treatment exerted a positive influence on the structure and rheological properties of WHBF, including an elevation in pasting temperature and viscosity. Notably, CIPD-treated WHBF exhibited higher storage modulus and loss modulus compared to the other three groups of sterilization treatments, contributing to the formulation of a better-defined and stable gel strength (tan δ = 0.38). UV-C and ozone, as cold sterilization techniques, also induced alterations in specific characteristics of WHBF. UV-C treatment led to changes in WHBF's crystallinity, while ozone treatment caused modifications in the secondary protein structure of WHBF. A total of 68 VOCs were identified in raw WHBF (including 3 acids, 19 alcohols, 25 aldehydes, 1 alkene, 8 esters, 2 ethers, 3 furans, and 7 ketones). The maximum flavor-contributing VOC in CIPD-treated WHBF remained dimethyl sulfide monomer (cabbage aroma), consistent with the raw WHBF. Conversely, in HA-treated WHBF, the maximum flavor-contributing VOC shifted to 2-furanmethanethiol monomer (roasted coffee aroma), altering the initial flavor presentation. These findings will provide strong support for the application of CIPD technology in the powdery foods industry.

Effects of egg powder on the structure of highland barley dough and the quality of highland barley bread.

The influences of egg white (EW), egg yolk (EY) and whole egg (WE) on the structure of highland barley dough and the quality of highland barley bread were explored. The results showed that egg powder reduced G' and G" of highland barley dough, which led to the softer texture of dough and endowed bread with a larger specific volume. EW increased the percentage of ß-sheet of highland barley dough, EY and WE promoted the transformation from random coil to ß-sheet and α-helix. Meanwhile, more disulfide bonds were formed from free sulfhydryl groups in the doughs with EY and WE. These properties of highland barley dough could help highland barley bread develop a preferable appearance and textural feature. It is worth noting that highland barley bread containing EY has more flavorful substances and a better crumb structure, which were similar to that of whole wheat bread. The highland barley bread with EY received a high score according to the sensory evaluation in consumer acceptance.

Effects of semidry milling on the properties of highland barley flour and the quality of highland barley bread.

BACKGROUND: This study aimed to investigate the effects of semidry milling on the quality attributes of highland barley flour and highland barley bread. Highland barley flours were prepared by dry (DBF), semidry (SBF), and wet (WBF) milling methods. The properties of different highland barley flours were analyzed, and highland barley breads made from different highland barley flours were evaluated. RESULTS: The results showed that WBF had the lowest damaged starch content (15.2 g kg-1 ), and the contents of damaged starch in SBF-35 and SBF-40 (43.5 g kg-1 and 24.1 g kg-1 respectively) were lower than that of DBF (87.6 g kg-1 ). And SBF-35 and SBF-40 with large particles exhibited low hydration performance. In addition, SBF-35 and SBF-40 had higher pasting viscosity, pasting temperature, ΔH, and relative crystallinity, consequently resulting in better gel properties than other highland barley flours. These properties could help SBF-35 and SBF-40 develop high-quality bread with large specific volume and superior crumb structure and texture that is similar to the bread with WBF. CONCLUSION: Overall, semidry milling not only could improve the characteristics of HBF, but also avoid high starch damage by dry milling and water wasting by wet milling. What is more, highland barley breads with SBF-35 and SBF-40 had preferable appearance and crumb texture. Therefore, semidry milling could be regarded as a feasible way to produce highland barley flour. © 2023 Society of Chemical Industry.

Physicochemical properties and in vitro digestibility of highland barley starch with different extraction methods.

The objective of this study was to compare the structural, thermal, rheological and digestive properties of highland barley starch (HBS) by different extraction methods. Five techniques were used to extract HBS: Alkali extraction, Ultrasound extraction, double enzyme extraction (DE), three enzyme extraction (TE) and ultrasonic assisted TE (U-TE). The results indicated that the Ultrasound extracted HBS had fewer Maltese crosses, lower molecular weight (Mw), and higher content of damaged starch (P < 0.05). Meanwhile, DE extracted HBS had higher Mw, and the content of short amylopectin than that of Alkali extracted HBS (P < 0.05). Additionally, the DE extracted HBS showed the highest relative crystallinity and good short-range ordered structure, which led to the outcome of stronger thermal stability and higher values of G' and G'' (P < 0.05). These results indicated that enzymatic extraction could better protect the resistance of HBS by protecting its physicochemical properties.

The structural and functional properties of dietary fibre extracts obtained from highland barley bran through different steam explosion-assisted treatments.

The effects of steam explosion (SE)-assisted ultrasound (SEU), citric acid (SEC), sodium hydroxide (SEA), and cellulase (SEE) treatment on the properties of soluble dietary fibre (SDFP) extracted from highland barley bran were analysed. The results showed that SE pretreatment combined with other methods effectively improves the SDFP yield. The highest yield of SDF (20.01%) was obtained through SEA treatment. SEU-SDFP had a loose and porous structure, whereas the surface of SEC-SDFP and SEA-SDFP presented a complicated and dense texture. Although SE pretreatment reduced the thermal stability of SDFP, SEC and SEE treatment maintained its thermal stability. Furthermore, SEU-SDFP exhibited the highest water and oil holding capacities, and cholesterol and nitrite ion adsorption capacities. SEE-SDFP exhibited the best DPPH and ABTS radical scavenging abilities. In summary, four SE-assisted extraction methods had different advantages, and highland barley bran SDF can be considered as a potential functional additive in the food industry.

Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch.

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value (p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption (p < 0.05). Moreover, E-HBS had not only higher G' and G″ values, but also the highest gel hardness value, reflecting its strong gel structure (p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.

Understanding the Palatability, Flavor, Starch Functional Properties and Storability of Indica-Japonica Hybrid Rice.

The rice quality and starch functional properties, as well as the storability of three YY-IJHR cultivars, which included YY12 (biased japonica type YY-IJHR), YY1540 (intermedius type YY-IJHR) and YY15 (biased indica type YY-IJHR), were studied and compared to N84 (conventional japonica rice). The study results suggested that the three YY-IJHR varieties all had greater cooking and eating quality than N84, as they had lower amylose and protein content. The starch of YY-IJHR has a higher pasting viscosity and digestibility, and there was a significant difference among the three YY-IJHR cultivars. Rice aroma components were revealed by GC-IMS, which indicated that the content of alcohols vola-tile components of YY-IJHR were generally lower, whereas the content of some aldehydes and esters were higher than N84. In addition, YY-IJHR cultivars' FFA and MDA contents were lower, which demonstrated that YY-IJHR had a higher palatability and storability than those of N84 in fresh rice and rice stored for 12 months. In conclusion, this study suggested that YY-IJHR had better rice quality and storability than N84. PCA indicated that the grain quality and storability of YY12 and YY15 were similar and performed better than YY1540, while the aroma components and starch functional properties of YY-IJHR cultivars all had significant differences.

Edible qualities, microbial compositions and volatile compounds in fresh fermented rice noodles fermented with different starter cultures.

To shorten the fermentation time and reduce the heterozygous bacteria contamination during fresh fermented rice noodles (FFRNs) fermentation, four starter cultures that consist of Limosilactobacillus fermentum, Lactoplantibacillus plantarum and Saccharomyces cerevisiae were used to produce FFRN. The cooking qualities and texture profiles of FFRNs, the dynamics of microbial diversities and volatile compounds at different fermentation stages were explored. Results showed that the fermentation time of the adding starter culture groups required 12 h, while that the natural fermentation (NF) group required 36 h. Significant differences were observed in the texture profiles and cooking qualities of these five groups FFRNs (P ＜ 0.05). In addition, compared with NF group, the microbial diversity of four adding starter culture groups was significantly lower, which meant that the edible safety of FFRNs could be enhanced. Meanwhile, a total of 115 volatile compounds were detected by Gas chromatography-ion Mobility Spectrometry and Gas chromatography-mass spectrometry, the aldehydes, alcohols, acids and esters were increased while aldehydes were decreased in FFRNs during fermentation. Among these, the relative odor activity value of 50 volatile compounds was greater than 0.1, contributing unique flavors to FFRNs. Notably, the flavor of Lactoplantibacillus plantarum + Saccharomyces cerevisiae (L.p + S.c) and Lactoplantibacillus plantarum + Limosilactobacillus fermentum + Saccharomyces cerevisiae (L.pf + S.c) groups was richer than that of other groups.