Effect of oxidized starch on the storage stability of frozen raw noodles: Water distribution, protein structure, and quality attributes.

Freezing is a popular method of food preservation with multiple advantages. However, it may change the internal composition and quality of food. This study aimed to investigate the effect of modified starch on the storage stability of frozen raw noodles (FRNs) under refrigerated storage conditions. Oxidized starch (OS), a modified starch, is widely used in the food industry. In the present study, texture and cooking loss rate analyses showed that the hardness and chewiness of FRNs with added OS increased and the cooking loss rate decreased during the frozen storage process. Low-field nuclear magnetic resonance characterization confirmed that the water-holding capacity of FRNs with OS was enhanced. When 6% OS was added, the maximum freezable water content of FRNs was lower than the minimum freezable water content (51%) of FRNs without OS during freezing. Fourier-transform infrared spectroscopy showed that after the addition of OS, the secondary structures beneficial for structural maintenance were increased, forming a denser protein network and improving the microstructure of FRNs. In summary, the water state, protein structure, and quality characteristics of FRNs were improved by the addition of OS within an appropriate range.

Effects of freeze-thaw cycles on the quality of Hot-dry noodles: From the moisture, starch, and protein characteristics.

Freeze-thaw cycles (FTC) could cause damage to food during storage. The effects of different FTC on Hot-dry noodles (HDN) in terms of quality, moisture, starch, and protein characteristics were studied. This study showed that FTC decreased the texture properties and water absorption of HDN. Meanwhile, cooking loss was significantly increased after FTC. The water content of HDN was decreased and water migration was increased during FTC. In addition, results showed that FTC destroyed the order structure and increased the crystallinity of starch in HDN. Under FTC, the disulfide bond of HDN was broken, the free sulfhydryl group was increased, and the electrophoretic patterns confirmed the protein depolymerization. The microstructure also showed that the gluten network became incomplete and starch was exposed outside the substrate. This study expounded the mechanism of HDN quality deterioration during FTC, which laid a foundation for the development and improvement of frozen and freeze-thaw noodles.

A simple fluorescence pyrocatechol-polyethyleneimine detection method for 3-MCPD.

A rapid fluorescence detection method was established for 3-monochloropropane-1,2-diol (3-MCPD). The detection system works based on the fluorescence quenching of pyrocatechol-polyethyleneimine (PCh-PEI) polymer by 3-MCPD. The fluorescence quenching ability of 3-MCPD for PCh-PEI polymer was measured at different pH and temperatures. Indeed, in the presence of 3-MCPD, the fluorescence intensity of PCh-PEI polymer solution was quenched best at 100 °C and pH 8.5. Also, the effect of different concentrations of 3-MCPD on the optical properties of the PCh-PEI polymer was examined. Under optimal experimental conditions, fluorescence detection was linear in a range of 0.08-2.0 mg per L 3-MCPD, with a calculated detection limit of 0.06 mg L-1 and a correlation coefficient of 0.9974. Concisely, the reported method has good sensitivity and can be used for the rapid detection of 3-MCPD contamination in food products.

Study on physicochemical properties and anti-aging mechanism of wheat starch by anionic polysaccharides.

The anti-aging effects of two anionic polysaccharides AG (sodium alginate)/SSPS (soluble soybean polysaccharide) and WS (wheat starch) were evaluated, and their different mechanisms were explored. The rheological properties, gelatinization properties and aging properties were characterized. The addition of AG and SSPS changed the gelatinization parameters of WS, decreased the peak viscosity, breakdown viscosity and setback viscosity, and enhanced the fluidity of the gel system. Additionally, the starch molecular orderliness experiment showed that the relative crystallinity of starch gels decreased with the increase in AG and SSPS concentrations, indicating that the rearrangement of amylopectin was disturbed, which inhibited the cross-linking of starch molecules. The water state analysis showed that the hydrophilicity of AG and SSPS and their interactions with starch molecules influenced the relaxation behavior of water protons in the gel system in a concentration-dependent manner. In conclusion, the addition of AG and SSPS could significantly inhibit the aging of WS gels, probably due to the competition effect of AG and SSPS on water and the interaction with starch molecules. The present study results would provide new theoretical insights into WS-based food research.

Retrogradation inhibition of wheat starch with wheat oligopeptides.

Starch staling greatly reduces the cereal products quality, and the staling retardation becomes a focus in current research. The effect of wheat oligopeptide (WOP) on anti-staling properties of wheat starch (WS) was studied. Rheology property indicated that WOP reduced WS viscosity, showing more liquid-like behavior. WOP improved the water holding capacity, inhibited swelling power, and reduced the hardness of WS gels, which decreased from 1200 gf to 800 gf compared with the control after 30 days storage. Meanwhile, the water migration of WS gels were also reduced with WOP incorporation. The relative crystallinity of WS gel with 1% WOP was reduced by 13.3%, and the pore size and the microstructure of gels was improved with WOP. Besides, the short-range order degree reached the lowest value with 1% WOP. In conclusion, this study explained the interaction between WOP and WS, which was beneficial to the application of WOP in WS-based food.

Interpretation of the effects of hydroxypropyl starch and hydroxypropyl distarch phosphate on frozen raw noodles quality during frozen storage: Studies on water state and starch-gluten network properties.

The impacts of both structural variations induced by low temperature and physiochemical changes induced by modified starch on the qualities of frozen raw noodles (FRNs) were investigated during long-term freezing storage. The addition of modified starch was a potentially effective method to delay the loss of FRNs qualities during storage. In this study, hydroxypropyl starch (HPS) and hydroxypropyl distarch phosphate (HPDSP) were added to improve the cooking and textural characteristics of FRNs. The cooking loss rate of FRNs with the addition of 12%HPS was consistent with that of the control (4.39 % and 4.37 %, respectively), while after 8 weeks of storage showed the significant decrease effect (5.01 % and 5.78 %, respectively). In addition, adding HPS or HPDSP could change the colour and lustre of FRNs to that preferred by consumers. When 6 % HPS or HPDSP were added, the FRNs showed the lowest of freezable water content during storage. The test results of FTIR showed the secondary structure of FRNs was maintained with the introduction of HPS or HPDSP during refrigeration, and the microstructure was improved during the frozen storage period. Consequently, the results provided a theoretical basis and new insight for the production and transportation of FRNs.

Synergistic effect of endogenous gluten and oleic acid on wheat starch digestion by forming ordered starch-fatty acid-protein complexes during thermal processing.

The aim of this study was to understand the potential of endogenous gluten inhibiting the digestibility in vitro of wheat starch (WS) in starch-fatty acid-protein system. Therefore, the influences of gluten and whey protein isolate (WPI) on the properties, multi-scale structure and in vitro digestibility of WS in WS-oleic acid (OA)-protein system were compared. The results of digestibility in vitro indicated that the ternary system of starch-fatty acid-protein showed higher resistant starch (RS) content as well as lower rapidly digestible starch (RDS) content than the binary system of WS-OA, demonstrating protein decreased WS digestion of WS-OA system. The results of pasting properties showed that gluten and WPI both increased the viscosities of WS-OA system during the cooling period due to the formation of WS-OA-protein ternary complex. The results of swelling power and solubility analysis showed that gluten and WPI both decreased the swelling power and solubility of WS-OA binary system. Laser Confocal Raman and X-ray diffraction (XRD) studies indicated that gluten and WPI both increased the ordered degree of WS-OA binary system by decreasing the full width at half maximum (FWHM) of the peak at 480 cm-1 and increasing crystallinity degree. Strikingly, compared with WPI, gluten had greater effects on the digestibility in vitro, pasting properties and ordered degree of WS in WS-OA-protein system. Therefore, gluten as an endogenous protein has the potential application in reduction the enzymatic digestibility of WS by regulating the reassembly of starch and fatty acid during thermal processing.

Insight into the effect of garlic peptides on the physicochemical and anti-staling properties of wheat starch.

The staling of wheat starch in storage seriously damages the quality of starch-based foods, and how to delay the staling has become a topic focus. To solve the problem, this study analyzed the effect of garlic peptides on the physical and retrogradation behaviors of wheat starch during storage. The rheological, pasting, swelling properties, molecular order, water migration, and microstructure of wheat starch gels were evaluated. Our results showed that garlic peptides effectively reduced the storage and loss modulus of wheat starch. The physical properties indicated that garlic peptides suppressed the swelling and gelatinization of starch, which exhibited higher water holding capacity and lower water migration. In addition, garlic peptides incorporated wheat starch exhibited the lowest gel hardness during storage. X-ray diffraction and Fourier Transform Infrared Spectroscopy analysis indicated that garlic peptides could reduce the crystallinity and inhibit the formation of ordered structures in wheat starch gel. The microstructure observation showed that the gel with garlic peptides maintained the integrity of the network structure. Consequently, garlic peptides are expected to be an effective natural additive to inhibit starch staling and provide new insights for starch-based foods.

Effect of mulberry leaf polysaccharides on the baking and staling properties of frozen dough bread.

BACKGROUND: Deterioration in frozen dough bread easily occurs in store, resulting in tremendous economic waste. Therefore, it is imperative to find natural additives to improve storage staling. The effects of mulberry leaf polysaccharides (MLP) were studied in terms of baking, retrogradation and microstructural aspects in frozen dough bread. RESULTS: The incorporation of MLP improved the specific volume and reduced the hardness of bread during room storage, with 1% MLP showing the best results. The results of X-ray diffraction and Fourier transform infrared spectroscopy showed that crystallinity was decreased and the formation of double helical structure was inhibited with the incorporation of MLP. Meanwhile, the results of low-field nuclear magnetic resonance demonstrated that the addition of MLP was advantageous for retarding water migration and distribution, with reduced water loss. It can be seen intuitively from scanning electron microscopy that MLP improved the gluten network with a smoother and flatter system. CONCLUSION: MLP improved the quality of bread during storage and delayed the degradation of internal structure, and can be used as an effective natural additive to improve the storage stability of baked food. 1% MLP showed the best results. © 2022 Society of Chemical Industry.

Effect of ß-cyclodextrins on the physical properties and anti-staling mechanisms of corn starch gels during storage.

The aim of this study was to investigate the effects of ß-cyclodextrin (ß-CD) and hydroxypropyl-ß-cyclodextrin (HP-ß-CD) on the physical and anti-staling properties of corn starch (CS). It was found that the addition of ß-CDs significantly decreased the storage and loss modulus of CS gel. Moreover, it reduced CS gel setback viscosity and hardness, in which HP-ß-CD primarily exhibited a more pronounced effect. The long and short-range ordered structure showed that the relative crystallinity of CS gel was delayed with the ß-CDs incorporation. Meanwhile, the ß-CDs promoted the inhibition of water migration. In addition, the microstructure observation showed that ß-CDs can better maintain the stability of CS gel structure during storage. Consequently, the addition of ß-CDs could delay the retrogradation of CS gel, and the introduction of hydroxypropyl groups was more effective, which provided a theoretical basis and new insights for the production of starch-based food industrial products.

Effects of chitosan oligosaccharide and hyriopsis cumingii polysaccharide on the quality of wheat flour and extruded flour products.

ABSTRACT: Effects of chitosan oligosaccharide (COS) and hyriopsis cumingii polysaccharide (HCP) on the quality of wheat flour and corresponding extruded flour products were investigated in this work. The results showed that both COS and HCP are conducive to the improvement of dough quality. Moreover, compared to control group samples, the moisture content, expansion ratio and oil absorption rate of the samples were increased and the hardness were decreased with the addition of COS. These phenomena indicate the quality of extruded flour products became better in the presence of COS as well. However, HCP has little or no effect on the quality of extruded flour products may be due to its degradation under high temperature and pressure extrusion. COS with higher stability exhibited better improvement effects on the quality of extruded flour products and showed a promising prospect for application in extruded food industry.

Effect of hydrocolloids on physical, thermal and microstructure properties of par-baked baguette during frozen storage.

The retrogradation of starch occurs in the process of freezing storage of par-baked baguette, resulting in easy staling and a decrease of consumer acceptance. The objective of this study was to assess whether the staling of par-baked baguette could be improved by the addition of Arabic gum (AG), Sodium alginate (SA), and Sesbania gum (SG). The physical, thermal dynamic, and microstructure properties of par-baked baguette during frozen storage were analyzed. The addition of hydrocolloid increased the moisture of the baguette and delayed the water migration, which was beneficial to improve the dough formation and gas capacity, hinder the growth of ice crystals, and reduce the hardness of the baguette. These properties were more pronounced with increasing freezing storage periods. These hydrocolloids could slow down the rate of recrystallization, which reduced the enthalpy change and crystallinity of par-baked baguette. It was also found that the hydrocolloids incorporated baguette was smooth in the crumb microstructure. In general, these results suggested that the incorporation of hydrocolloids improved the quality and anti-staling mechanism of the par-baked baguette during frozen storage which can be used as potential improvers to increase freezing stability in the formulation of the baguette.

The Addition of α-cyclodextrin and γ-cyclodextrin Affect Quality of Dough and Prebaked Bread During Frozen Storage.

The effects of the addition of 0-3.0 wt% α-cyclodextrin (α-CD) and γ-cyclodextrin (γ-CD) on the quality of wheat flour as well as the texture and the aging of prebaked bread were evaluated. The addition of α-CD and γ-CD increased the ability of wheat flour to absorb water and shortened the times of dough formation and stabilization. Amylase activity slightly increased after using 2.0 and 3.0 wt% of α-CD and γ-CD, respectively. Moreover, the addition of α-CD and γ-CD increased the fermentation height and gas retention ability of dough. Dough samples containing 2.0 wt% α-CD and 3.0 wt% γ-CD showed the highest fermentation heights and gas retention volumes, respectively. Dough gas production increased with the addition of γ-CD. Gas production by dough samples containing more than 2.0 wt% α-CD exceeded that by samples in the control group. The results of the texture crumb of bread and specific volume tests revealed that the addition of 2.0 wt% α-CD and 3.0 wt% γ-CD reduced bread hardness and increased bread elasticity, resilience, and specific volume. The optimal α-CD and γ-CD contents were identified as 2.0 wt% and 3.0 wt%, respectively. The addition of 2.0 wt% α-CD and 3.0 wt% γ-CD delayed the aging of prebaked bread and reduced the hardness of prebaked bread during different weeks of storage, which may be due to decreasing the melting enthalpy of starch crystals. This work elucidated the mechanisms underlying the effects of CD addition on prebaked bread quality.

Toxicological evaluation of advanced glycation end product Nε-(carboxymethyl)lysine: Acute and subacute oral toxicity studies.

Nε-(carboxymethyl)lysine (CML) as a novel potential noxious compound in various food products has aroused extensive concern in recent years. This study aimed to investigate the oral acute and subacute toxicity of CML in mice as per OECD 420 and 407 guidelines. Acute administration of 2000 and 5000 mg/kg CML did not induce any mortality within 14 days, nevertheless some toxicological symptoms and histopathological changes were observed. The estimated LD50 of CML was >5000 mg/kg. In subacute toxicity test, CML was dosed at 200, 500 and 1000 mg/kg in both genders for 28 days. The body weights reduced which was accompanied with the decrease of food consumptions. Hematology parameters viz. RBC, HGB and MCH showed minor alteration but these were still within normal range. Biochemical analysis of hepatic and renal function markers showed significant elevating in AST, ALT, Cr and BUN etc. Histopathological alterations were observed in lung, liver, kidney and spleen. Subacute toxicity of CML involved oxidative stress caused by reducing antioxidant enzyme (SOD and GSH-Px) activities, and significantly increasing lipid peroxide (MDA) level. In conclusion, CML was unlikely to present an acute hazard, but repeated administration could produce deleterious effects on mice especially inducing liver and kidney damage through oxidative stress.

[Determination of 6 antiestrogens in fish tissues by ultra performance liquid chromatography-tandem mass spectrometry].

A comprehensive analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of 6 antiestrogens (toremifene, clomiphene, tamoxifen, raloxifene, anastrozole and letrozole) in fish muscle and liver. The multi-reaction monitoring mode was employed for the determination. The homogeneous fish tissue samples were ultrasonically extracted with acetonitrile, and then the supernatants were diluted by water. The target compounds were concentrated and purified by a mixed-mode cationic-exchanger (MCX) cartridge, and then separated on an ACQUITY UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 microm) using a binary mobile phase gradient with water containing 0.1% formic acid and acetonitrile. The limits of quantification (LOQ, S/N = 10) of the 6 antiestrogens were 0.1 - 0.3 microg/kg in muscle and liver samples. The average recoveries of target compounds (spiked at four concentration levels) based on internal standard calibration were in the range of 84.9% - 112.2% with the relative standard deviations of 0.9% - 14.3%. This method can be applied to the trace analysis of target drugs in fish muscle and liver samples.