Setback Value Research Articles

Effects of lactic acid bacteria fermentation on the physicochemical and structural characteristics of starch in blends of glutinous and japonica rice.

In this study, the effects of lactic acid bacteria (LAB) fermentation on the physicochemical and structural characteristics of mixed starches in blends of glutinous and japonica rice were investigated. Five starter cultures improved in varying degrees the hydration ability, transparency, and freeze-thaw stability of the mixed starches. Mixed starch I, prepared by fermentation of Lactobacillus acidophilus HSP001, exhibited optimal water-holding capacity, solubility, and swelling power. In comparison, mixed starches V and III involved fermentation of L. acidophilus HSP001 and Latilactobacillus sakei HSP002, using ratios of 2:1 and 1:1 to achieve higher transparency and freeze-thaw stability, respectively. The LAB-fermented, mixed starches exhibited excellent pasting properties due to their high peak viscosities and low setback values. Moreover, the viscoelasticity of mixed starches III-V, prepared by compound fermentation of L. acidophilus HSP001 and L. sakei HSP002 in ratios of 1:1, 1:2, and 2:1, respectively, proved superior to their single strain fermentation counterparts. Meanwhile, LAB fermentation resulted in reduced gelatinization enthalpy, relative crystallinity, and short-range ordered degree. Thus, the effects of five LAB starter cultures on mixed starches were inconsistent, but these results provide a theoretical basis for the application of mixed starches. PRACTICAL APPLICATION: Lactic acid bacteria was used to ferment blends of glutinous and japonica rice. Fermented mixed starch had better hydration, transparency, and freeze-thaw stability. Fermented mixed starch exhibited nice pasting properties and viscoelasticity. LAB fermentation corroded starch granules, leading to the decrease of ΔH. Relative crystallinity and short-range order of fermented mixed starch decreased.

Peroxidase inactivation by cold plasma and its effects on the storage, physicochemical and bioactive properties of brown rice

Dielectric barrier discharge cold plasma (DBD-CP) was applied to brown rice either in the form of whole brown rice or in brown rice powder in order to inactivate peroxidase. Afterwards, the DBD-CP stabilized whole brown rice (CPR) and brown rice powder (CPP) were compared through their storage, physicochemical and bioactive properties. Results demonstrated that peroxidase was completely inactivated in CPP rather than in CPR, and the fat acidity in CPP was significantly lower than that in CPR and raw brown rice during accelerated storage. Besides, the etching effect of DBD-CP induced many scorched spots and micropores respectively in the surface of CPR and CPP, which significantly increased their water absorption index and pasting viscosities. Specially, the starch and protein molecules were depolymerized in CPR, while they were cross-linked in CPP. Consequently, the effects of DBD-CP on gelatinization enthalpy, setback value and water solubility index differed in CPR and CPP. Furthermore, CPR was better for the retainment of phenolic compounds and antioxidant activity than CPP. Therefore, DBD-CP was useful to improve the shelf life of brown rice, and its effects on the storage, physicochemical and bioactive properties were highly depended on the form of brown rice to be processed.

Increasing basal nitrogen fertilizer rate improves grain yield, quality and 2-acetyl-1-pyrroline in rice under wheat straw returning.

Straw returning plays an essential role in crop yields and the sustainable development of agriculture. However, the effects and mechanisms of nitrogen (N) fertilizer management on grain yield, quality and aroma substance 2-acetyl-1-pyrroline (2-AP) content under wheat straw returning are still unclear. In this field experiment, two japonica rice cultivars were used as materials, wheat straw non-returning (NS) and wheat straw full returning (WS) were designed coupled with two N application ratios, namely basal fertilizer: tiller fertilizer: panicle fertilizer =5:1:4 (local farmers' fertilizer practice, LFP) and 7:1:2 (increasing basal fertilizer rate, IBF) under the total N application rate of 270kg ha-1. The effects of the four treatment combinations (NS-LFP, NS-IBF, WS-LFP, WS-IBF) on yield, cooking and eating quality, and 2-AP content in rice were investigated. The two-year (2020, 2021) results showed that: 1) WS-IBF significantly increased the number of panicles and grains per panicle, leading to the increase in grain yield by 6.67%-12.21%, when compared with NS-LFP, NS-IBF and WS-LFP. 2) WS-IBF enhanced the taste value, peak viscosity, breakdown value, the ratio of amylopectin to amylose, and the ratio of glutelin to prolamin while reducing the setback value and amylose content of rice flour. 3) Compared with NS, WS increased the activities of proline dehydrogenase and ornithine transaminase, the synthetic precursors of 2-AP, and finally increased 2-AP content in rice grains. WS-IBF slightly decreased 2-AP content, but there was no significant difference with WS-LFP. The above results indicated that adjusting the N regime and increasing basal N fertilizer rate under wheat straw returning is conducive to improving grain yield, cooking and eating quality, and 2-AP content in rice.

Changes in the physicochemical and protein distribution properties of dough with the wheat oligopeptide incorporation

The characteristics of the dough modification are crucial to the quality of the final product. This study aimed to investigate the effects of wheat oligopeptide (WOP) on dough rheology, physicochemical, and protein distribution properties. Rheological results showed that WOP increased the viscoelasticity, extensibility, and strength of the dough. The pasting experiments illustrated that WOP decreased the peak viscosity, breakdown, and setback values. The fermentation results showed that WOP significantly increased the fermentation height and gas-holding rate of the dough. Meanwhile, the water migration ability of the dough was significantly inhibited after WOP incorporation. Furthermore, the electrophoresis results further proved that WOP could effectively enhance the aggregation of small molecule proteins. The microstructure results further demonstrated that the dough exhibited more uniform and continuous characteristics with the WOP incorporation, which was consistent with our hypothesis. In conclusion, WOP has the ability to strengthen the dough network structure, providing a new idea for future modification of dough and its products.

Preparation and characterization of type 3 resistant starch by ultrasound-assisted autoclave gelatinization and its effect on steamed bread quality.

In this study, we aimed to establish an innovative and efficient preparation method of potato resistant starch (PRS). To achieve this, we prepared type 3 resistant starch (RS3) from native potato starch (PS) using an ultrasonic method combined with autoclave gelatinization and optimized by the response surface method to study the structure and properties of potato RS3 (PRS3) and its effect on the quality of steamed bread. Under optimal treatment conditions, the PRS3 content increased from 7.5% to 15.9%. Compared with PS, the B-type crystal structure of PRS3 was destroyed, and the content of hydroxyl groups was increased, but no new chemical groups were introduced. PRS3 had a rougher surface and a lower crystallinity, gelatinization temperature, viscosity, setback value, and breakdown value. The low content (5%) of PRS3 had a stable viscosity and was easily degraded by bacteria, which can improve the quality of steamed bread to a certain extent. When the PRS3 content was over 10%, it competed with the gluten protein to absorb water, which reduced the contents of β-turn and α-helix in the dough, increased the contents of β-fold, and weakened the structure of the gluten network. It also decreased the specific volume and elasticity of the steamed bread and increased the spreading rate, hardness, and chewiness. Steamed bread prepared with a flour mixture containing 5% PRS3 was similar to the presidential acceptance of control flour. In this study, a new sustainable and efficient PRS3 preparation method was established, which has certain guiding significance for the processing of Functional steamed bread with high-resistant starch.

Effects of Laminaria japonica polysaccharides on gelatinization properties and long-term retrogradation of wheat starch

This study investigated the effects of LJP (Laminaria japonica polysaccharides) on the rheological, gelatinization, and retrogradation properties of WS (wheat starch) gels. Dynamic rheological test showed that the addition of LJP decreased the storage and loss modulus. Furthermore, LJP significantly decreased the peak viscosity, breakdown, and setback value of WS. Moreover, LJP incorporation significantly reduced the WS gel hardness during storage. SEM results showed that the addition of LJP improved the structure of WS gel. The short and long-range ordered structure showed that the relative crystallinity and formation of ordered structure were reduced with the addition of LJP. Otherwise, the LJP inhibited moisture migration, which was demonstrated by LF-NMR. In summary, the addition of LJP could inhibit the retrogradation of WS gel, as well the double helix structure of amylose or amylopectin was decreased, which provides a new theoretical insight for the production of WS-based food study. • Laminaria japonica polysaccharides (LJP) showed a restraint effect on WS gels retrogradation. • LJP reduced the storage and loss modulus and gelatinization index of WS gels. • LJP in WS gels can interfere with the recombination of the double helix structure of starch during storage.

Gelatinization and Retrogradation Properties of Wheat Starch with Added Konjac Glucomannan or Artemisia sphaerocephala Krasch. Gum

AbstractThis work evaluates the effect of the various proportions of konjac glucomannan (KGM) and Artemisia sphaerocephala Krasch. Gum (ASKG) on the gelatinization structure, and retrogradation characteristics of wheat starch (WS). The Rapid Viscosity Analyzer (RVA), iodine colorimetric reaction, Scanning Electron Microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction analysis (XRD), and dynamic time sweep measurements, among other instruments are used to evaluate the structural properties, gelatinization, and retrogradation characteristics of WS, KGM/WS mixture, and ASKG/WS mixture. The addition of KGM/ASKG to WS improves the peak viscosity, final viscosity, breakdown value, setback value, swelling power, G′ and G″ values, and tan δ. Meanwhile, the amount of amylose leached, retrogradation enthalpy, and relative crystallinity reduced, and the gel structure appears to become more consistent and stable, with an increase in the number of inter‐ and intramolecular hydrogen bonds. These findings show that the presence of an interaction between KGM/ASKG and WS, boosted gel intensity and textural qualities while suppressing short and long‐term WS retrogradation.

Response of yield and quality of giant embryo rice to nitrogen application and analysis of lipid-lowering effect.

Giant embryo rice is known as a highly nutritious functional rice because it is rich in gamma-aminobutyric acid (GABA), which has various regulatory functions in the human body. To study the response of giant embryo rice yield and quality to nitrogen (N) application, and to verify the effect of giant embryo brown rice on alleviating hyperlipidemia in rats. In this study, field experiments were conducted in 2020 and 2021 using the giant embryo rice varietiers J20 (japonica) and Koshihikari (japonica) rice as experimental materials and five N levels, 0 (N0), 90 (N1), 135 (N2), 180 (N3) and 225 (N4) kg ha-1. The results showed that the yield of both varieties increased with increasing N and the maximum values were observed under the N2 treatment. As more N was gradually applied, the brown rice rate, milled rice rate, head rice rate and GABA content of both varieties first increased and then decreased, while the chalky grain rate and chalkiness showed the opposite trend. The optimal values of these indexes were observed under the N2 treatment. The peak viscosity and breakdown value of J20 decreased, while its setback value and pasting temperature increased with increasing N. In contrast, Koshihikari showed the opposite trend. The protein content and protein component contents of both varieties showed an increasing trend with increasing N, among which gliadin was the most sensitive protein component to N fertilizer. Animal experiments results showed that J20 brown rice could significantly slow the rate of weight gain of rats, reduce serum total cholesterol and triglyceride levels and increase high-density lipoprotein cholesterol levels. Therefore, increasing N could effectively enhance J20 yield and improve processing, appearance and nutritional quality but decrease cooking and eating quality. The brown rice J20 had the effect of slowing the rate of weight gain and reducing the hyperlipidemia level of rats, the optimal N application rate for achieving high yield, high quality and good functional characteristics in the giant embryo rice J20 was 135 kg ha-1. These findings will provide a theoretical and technical foundation for the popularization and application of giant embryo rice in the future.

The role of starch granule-associated proteins in enhancing the strength of indica rice starch gels

The gel properties of indica rice starch strongly influence the quality of foods in which it is used. This study investigated the effects of chymotrypsin treatment on the rheological and pasting properties of starch prepared by different treatment methods. The results demonstrated that all the starches contained starch granule-associated proteins (SGAPs). Specifically, chymotrypsin-treated fermented extracted starch (E-FS) and chymotrypsin-treated alkali extracted starch (E-AS) exhibited a storage modulus (Gʹ) about 4 times higher than that of fermented extracted starch (FS) and alkali-extracted starch (AS). The flow consistency coefficients (K), loss moduli (Gʺ) and setback values tended to increase, while the characteristic rheological indices (n) and loss tangent (tan δ) tended to decrease after chymotrypsin treatment. This suggested that the starch gel was significantly enhanced by the proteinase modification. The protein composition of AS and E-AS only contained the 66 kDa of granule-bound starch synthase I (GBSS I) subunit. Therefore, the significant increase in gel strength was attributed to the exclusive modification effects of GBSS I. Microstructural analysis also confirmed that the three-dimensional gel network of indica rice starch was formed by a backbone of SGAP polymers filled with starch granules. The mechanism underlying GBSS I-enhanced gel was also elucidated based on the sequence and structure of GBSS I. The gel network formed by SGAP polymers of FS and AS was mainly caused by disulfide bonds between GBSS Is, while that of E-FS and E-AS was mainly caused by hydrophobic interactions. • The gel properties of indica starch treated by different methods were studied. • Enzymatic modification of starch granule-associated proteins (SGAPs) increased the starch gel strength significantly. • The SGAPs were mainly composed of granule-bound starch synthase I (GBSS I). • Gel formation driving force changed from disulfide bonds to hydrophobic interactions. • The gel structure comprised a polymerized SGAP network filled with starch granules.

Effect of low‐temperature plasma treatment on the microbial inactivation and physicochemical properties of the oat grain

AbstractBackground and ObjectivesNaked oat grain is easily contaminated by microorganisms, and it needs pretreatment to extend its shelf life. Low‐temperature plasma treatment (LTPT) has the advantages of less energy consumption, safety, and convenience, and its applications in grain include microbial inactivation and flour modification. Therefore, we studied the changes in oat microbes and the physicochemical properties of oats at different plasma treatment times (0, 5, 10, 15, and 20 min at an output discharge voltage of 60 kV).FindingsThe results demonstrated that LTPT significantly decreased the number of microorganisms with the increase in treatment time, especially at 20 min. LTPT increased the L* and b* values and decreased the a* value of oat flour. Proper treatment time (5–10 min) did not affect the germination rate of the grain. Compared to the control sample, LTPT increased the water‐binding capacity and swelling power of flour and decreased the peak viscosity, final viscosity, and setback value. However, LTPT did not change the crystal structure. Besides, by fitting the peak of the amide region in Fourier transfer infrared analysis, it was found that the β‐sheet and α‐helix increased after treatment for 5–10 min.ConclusionsThese results indicated that LTPT (20 min) can effectively reduce the microbial count of oats and proper time treatment (5–10 min) can regulate the function of the flour and improve its quality.Significance and NoveltyLTPT as a new nonheat treatment technology can not only effectively reduce the microbial content of the grain but also improve the quality of the flour, which is a better pretreatment method for oat flour.

Effect of inulin on the pasting and retrogradation characteristics of three different crystalline starches and their interaction mechanism

At present, there are hardly any studies about the effect of inulin (IN) on the physicochemical properties and structures of different crystalline starches. In this study, three different crystalline starches (wheat, potato, and pea starch) were compounded with natural IN, and its pasting, retrogradation, and structural characteristics were investigated. Then, the potential mechanism of interaction between IN and starch was studied. The results showed that there were some differences in the effects of IN on the three different crystalline starch. Pasting experiments showed that the addition of IN not only increased pasting viscosity but also decreased the values of setback and breakdown. For wheat starch and pea starch, IN reduced their peak viscosity from 2,515 cP, 3,035 cP to 2,131 cP and 2,793 cP, respectively. Retrogradation experiment dates demonstrated that IN delayed gelatinization of all three starches. IN could reduce the enthalpy of gelatinization and retrogradation to varying degrees and inhibit the retrogradation of starch. Among them, it had a better inhibitory effect on potato starch. The addition of IN reduced the retrogradation rate of potato starch from 38.45 to 30.14%. Fourier-transform infrared spectroscopy and interaction force experiments results showed that IN interacted with amylose through hydrogen bonding and observed the presence of electrostatic force in the complexed system. Based on the above, experimental results speculate that the mechanism of interaction between IN and three crystalline starches was the same, and the difference in physicochemical properties was mainly related to the ratio of amylose to amylopectin in different crystalline starches. These findings could enrich the theoretical system of the IN with starch compound system and provide a solid theoretical basis for further applications.

Effects of Bifidobacteria Fermentation on Physico-Chemical, Thermal and Structural Properties of Wheat Starch.

Lactic acid bacteria have been considered to be a very important species during sourdough fermentation. In order to explore the effects of bifidobacteria fermentation on thermal, physico-chemical and structural properties of wheat starch during dough fermentation, starch granules were separated from the fermented dough at different fermentation times, including 0 h, 2 h, 6 h, 9 h and 12 h. The results showed that the morphology of starch granules was destroyed gradually as the fermentation time increased, which appeared as erosion and rupture. With the increase in fermentation time, the solubility showed a significant increase, which changed from 8.51% (0 h) to 9.80% (12 h), and the swelling power was also increased from 9.31% (0 h) to 10.54% (12 h). As for the gelatinization property, the enthalpy was increased from 6.77 J/g (0 h) to 7.56 J/g (12 h), indicating a more stable thermal property of fermented starch, especially for the longer fermentation. The setback value was decreased with short fermentation time, indicating that the starch with a longer fermentation time was difficult to retrograde. The hardness of the gel texture was decreased significantly from 50.11 g to 38.66 g after fermentation for 12 h. The results show that bifidobacteria fermentation is an effective biological modification method of wheat starch for further applications.

Insights into structural and physicochemical properties of maize starch after Fusarium verticillioides infection

Crop loss caused by toxigenic fungi is a standing problem for many cereals worldwide. In this study, structural and physicochemical changes of maize starch after F. verticillioides infection were evaluated. During the colonization, fungi use starch as the carbon source to provide nutrition for their growth and development resulting in the decline of the starch content of maize kernels. The maize starch was severely damaged and many holes were observed on the surface of starch granules when kernels were infected by F. verticillioides. Gel-permeation chromatography (GPC) analysis showed that amylopectin in maize starch was preferentially degraded and the content of amylose was increased. Simultaneously, the onset and peak of gelatinization temperatures of starch after fungal infection were raised. In comparison with native starch, the viscosity and setback value of infected starch was decreased. Furthermore, we found that 2 genes encoded by F. verticilllioides played important roles in starch degradation.

Physicochemical, rheological and structural properties of flours from six quinoa cultivars grown in Colombia

BackgroundInclusion of quinoa in the diet of consumers has generated a challenge for quinoa producers and food processors, which involves the study of new cultivars and the functional properties of their flours.MethodsSix quinoa cultivars (Titicaca, Blanca real, Soracá, Pasankalla, Puno and Nariño) were analyzed for their proximate composition using the methodologies proposed by the Association of Official Analytical Collaboration, AOAC. A rheological analysis was carried out with flours from each cultivar. A sequential test including a flow test, a pasting test and another flow test was programmed to evaluate the flow behavior before and after a heating process. In addition, the structural properties of the cultivar flours were evaluated by Fourier Transform Infrared spectroscopy (FTIR).ResultsIt was found that the Pasankalla, Titicaca and Soracá cultivars had a higher (p < 0.05) protein content, while the Puno, Pansakalla and Blanca real cultivars stood out for their higher (p < 0.05) lipid content. On the other hand, it was found that before heating, all quinoa flour dispersions had a dilatant flow (n > 1), but after heating, all of them showed a decrease of index values, where the flours of the Titicaca and Pasankalla cultivars were more affected with a tendency toward a Newtonian flow (n ≈ 1). The pasting test showed that the viscosity varied according to the cultivar tested. It is noteworthy that both Titicaca and Soracá presented a high peak viscosity (0.16 ± 0.01 and 0.13 ± 0.02 Pa·s respectively) and different setback values on cooling (0.100 ± 0.028 and 0.01 ± 0.01 Pa·s respectively). Spectroscopic analysis showed a direct relationship between the intensity of the peaks and the nutritional content of the flours. In addition, secondary protein structures such as β-sheet, β-Turn, α-Helix and Random Coil were identified after deconvolution of the spectra. The differences in the protein structures of each cultivar could allow their identification by this methodology.ConclusionIt can be concluded that quinoa flours from the six cultivars could be used for the formulation of different food products, such as beverages, baked goods, snacks, pasta and others, acting as nutritional improvers and modifiers of rheological, textural and functional properties.

Effect of soy protein hydrolysates incorporation on dough rheology, protein characteristic, noodle quality, and their correlations.

Soy protein hydrolysates (SPHs) have bioactive and nutritional functions that can be used as fortifier of noodles. The objective of this study is to explore the effect of SPHs on dough rheology and noodle quality. Two kinds of SPHs, with a hydrolysis degree of 4.43% (SPH4) and 7.47% (SPH7), were added to wheat flour at a ratio of 5:95 to make dough and noodles. The addition of SPHs decreased the gluten yield, gluten index, peak viscosity, final viscosity, and setback of flour paste. Dough stability decreased, but the extensibility increased because of the addition of SPHs. SPHs decreased the high molecular weight glutenin subunits and SDS-unextractable polymeric protein proportion, and the results of scanning electron microscopy and atomic force microscopy also showed that the gluten network in SPH7 dough was more discontinuous than that in SPH4, suggesting a stronger negative effect of SPH7 on the formation of the gluten network compared to that of SPH4. The incorporation of SPHs decreased the hardness and springiness of cooked noodles but increased their cooking loss, protein loss, and water absorption. The correlation analysis showed that high molecular weight subunits and SDS-unextractable polymeric protein in SPH-fortified dough were positively correlated with the hardness, adhesiveness, springiness, cohesiveness, chewiness, resilience, force, and distance at break of noodles, and these texture properties of noodles were positively correlated with pasting, gluten, and farinographical properties of SPH-fortified flour. These results suggested that SPHs could improve some qualities of noodles, such as smoothness and cooking yield, and resist pasted starch aging. PRACTICAL APPLICATION: Soy protein hydrolysates have many bioactive functions. This study demonstrated the feasibility of incorporating soy protein hydrolysates into wheat flour to prepare noodles. The addition of soy protein hydrolysates gives noodles smoother mouthfeel and increases the cooking yield. The addition of soy protein hydrolysates decreases the setback value of flour paste, suggesting that soy protein hydrolysates may help to resist starch aging, which is favorable for starch-containing foods such as precooked noodles. Thus, soy protein hydrolysates possess potential applications in noodle products.

Effect of Homogenization Modified Rice Protein on the Pasting Properties of Rice Starch.

Modification of plant-based protein for promoting wide applications is of interest to the food industry. Rice protein from rice residues was modified by homogenization, and its effect on pasting properties (including gelatinization and rheology) of rice starch was investigated. The results showed that homogenization could significantly decrease the particle size of rice protein and increase their water holding capacity without changing their band distribution in SDS-PAGE. With the addition of protein/homogenized proteins into rice starch decreased peak viscosity of paste. The homogenized proteins decreased breakdown and setback value when compared with that of original protein, indicating homogenized protein might have potential applications for increasing the stability and inhibiting short-term retrogradation of starch paste. The addition of protein/homogenized proteins resulted in a reduction in the viscoelasticity behavior of starch paste. These results indicate that homogenization would create a solution to alter the physicochemical properties of plant proteins, and the homogenized proteins may be a potential candidate for development of protein-rich starchy products.

Preliminary Characterization of Structural and Rheological Behavior of the Quinoa Hyperprotein-Defatted Flour

Protein functional properties are related to physical and chemical parameters that influence protein behavior in food systems during processing, storage and consumption. The structural and rheological properties of three quinoa hyperprotein flours (without defatting, WD, chemically defatted, CD, and mechanically defatted, MD) were evaluated. The values of the fluidity index (n) were significantly different (p < 0.05), which was associated with changes in protein or starch structures due to solvent treatments or heating of the flour during pressing. In addition, a strong dependence of the consistency index (k) on the shear rate was observed. For dispersions with a concentration of 12% (w/v), CD and WD had a significantly lower setback value than MD. The viscosity peak was affected by the presence of lipid molecules. Greater changes were evident in the β-sheet (1,610 and 1,625 cm−1) and β-spin (1,685 and 1,695 cm−1) structures. The changes identified in these structures were associated with the defatting treatment. Consequently, the intensity ratio 2,920/1,633 cm−1 was more sensitive to changes in the fat content of the flours. It was shown that defatting conditions increase the protein adsorption kinetics and that the viscoelastic properties of the protein increase when the flour has a lower fat content. Hyperprotein quinoa flour could be used to improve the protein content of products such as snacks, pastas, ice cream, bakery products, meat extenders, among others, due to its foaming, gelling or emulsifying capacity. The objective of this work was to study the effect of two types of defatting of hyperprotein quinoa flour on its structural and rheological properties.

Potential of raw and fermented maize gluten feed in bread making: Assess of dough rheological properties and bread quality

Maize gluten feed (MGF) is a secondary product of maize processing with rich dietary fiber content, which remains underexploited as an ingredient by the food industry. In this study, the impact of MGF and fermented MGF (FMGF) incorporation on dough properties and bread quality was investigated. The results indicated that both MGF and FMGF demonstrated beneficial effects on the water absorption, dough development time, setback value while exerting a negative impact on the dough stability time. A significant decrease in L value (extensibility) and W value (deformation energy), and a significant increase in P value (elasticity) were observed with MGF or FMGF incorporation in the dough. For fermentation properties, the maximum height of dough and the volume of the gas retained in dough during fermentation decreased with the substitution level increased. The bread incorporated MGF or FMGF decreased the specific volume, deepened the color, led to lower porosity, increased the crumb hardness and chewiness. MGF and FMGF bread showed a slight depreciation in quality with the substitution level below 10 g/100 g. Compared with MGF, FMGF displayed advantages in bread properties at below 10 g/100 g substitution level, indicating that fermentation is a promising technology for improving the processing properties of MGF.

Modification in structural, physicochemical, functional, and in vitro digestive properties of kiwi starch by high-power ultrasound treatment

Kiwi starch (KS) is a fruit-derived starch; in order to improve its processing performance and increase its added value, it is necessary to modify KS to enhance the positive attributes and to enlarge its application. In this study, KS was modified by high-power ultrasound treatment (HUT) to reveal the relationship between the structure and function of KS with different treatment powers (0, 200, 400, and 600 W) and different treatment times (0, 10, 20, and 30 min). The results showed that HUT destroyed the granular morphology of KS, formed holes and cracks on the surface, and reduced the particle size and the short-range molecular order of KS. After different HUTs, the apparent amylose content (AAC), swelling power (SP), water solubility index (WSI), viscosity and setback value (SB) of KS were significantly increased, while the gelatinization temperature was significantly decreased. In addition, HUT significantly reduced the content of rapidly digestible starch (RDS) and slowly digestible starch (SDS), while it significantly enhanced the content of resistant starch (RS) (64.08–72.73%). In a word, HUT as a novel physical modification method for KS, enlarged its application, and fulfilled different demands of a starch-based product, which introduces another possibility for kiwi fruit further processing.

Effects of konjac glucomannan on pasting, rheological, and structural properties of low-amylose rice starch

Abstract Blend of starch and polysaccharide is a secure and feasible modifying method for starch. Effects of konjac glucomannan (KGM) on pasting, retrogradation, rheological and structural properties of low-amylose rice starch were evaluated. KGM addition reduced the pasting temperature, breakdown and setback values, but raised the peak viscosity. When KGM concentration increased, the storage and loss moduli showed an upward trend. Fourier transform infrared spectroscopy (FTIR) showed redshifts at 3450 and 1640 cm−1 and suggested the formation of intermolecular hydrogen bond between KGM and starch molecules. X-ray diffraction (XRD) indicated that KGM decreased the relative crystallinity from 11.88 to 3.10%. Scanning electron microscopy (SEM) of KGM induced samples showed looser network structures, and confocal laser scanning microscopy (CLSM) detected less cloud-like blurry pastes surrounding around the starch ghosts. KGM addition suppressed the starch retrogradation. These results could be used to broaden the application of KGM in the food industry.