Formation and Alterations of the Potentially Harmful Maillard Reaction Products during the Production and Storage of Brown Fermented Milk

Analysis of unique volatile organic compounds in "Mianhua" made from wheat planted in arid alkaline land

Hebei Province's Huanghua "Mianhua" is a province intangible cultural property made from arid alkaline wheat (AAW). This study aims to assess how different soil conditions affect the volatile organic compounds (VOCs) of "Mianhua" and identify distinct VOCs for land type discrimination. These findings will guide future research on AAW products, enhancing their processing and utilization. 51 VOCs in "Mianhua" from wheat samples grown in arid alkaline land and general land in Huanghua were analyzed by Gas Chromatography-Ion Mobility Spectrometry (GC-IMS). The result of ANOVA, VOC fingerprint, T test, and OPLS-DA revealed VOCs differences based on planting environments. According to multivariate variance contribution rate analysis, most VOCs were more affected by the variety. Land type significantly influenced (E)-2-heptenal (75.3%), Butanol (60.6%), Propyl acetate (60.0%), ethyl pentanoate (45.5%), and ethyl acetate (44.4%). LDA progressively identified Butanol as the characteristic VOC to distinguish "Mianhua" between it made from AAW and general wheat (GW), with a classification accuracy of 75%.

Monitoring the Dough Properties, Quality Characteristics and Volatile Compounds of Whole Wheat Bread Made by Different Sourdough Types during Frozen Storage

There is a need to increase the consumption of whole wheat bread (WWB) due to its health benefits by overcoming its poor technological quality and improving its sensory characteristics. In this study, sourdough bread-making and frozen dough technology were combined to provide fresh WWB at any time with better quality. Also, it was aimed to investigate the effects of three types of sourdough (type I, II, and IV) on the final quality of WWB during frozen storage (-30 °C, 14 and 28 days). The tan δ of WWB with type I sourdough was highest at the end of the frozen storage. Freezable water content was lower on day 0 for WWB with type II and IV sourdough than other bread types. No significant effect of frozen storage was observed in bread types in terms of an α helix structure, except for WWB with type I sourdough. A lower hardness increment was shown in WWB with baker's yeast and WWB with type II sourdough over 14 days of frozen storage when compared to other bread types. WWB with type I sourdough and WWB with type IV sourdough were differentiated from other bread samples in volatile compound (VC) analysis on frozen storage days 28 and 0, respectively. The frozen storage of WWB with baker's yeast and WWB with type II sourdough caused no notable changes in the VCs profile. These results suggest that a less detrimental effect of frozen storage was observed in WWB with type II sourdough, indicating a more favorable choice for producing WWB with sourdough.

Exploring correlations between soy sauce components and the formation of thermal contaminants during low-salt solid-state fermentation

Soy sauce is a traditional seasoning in Asia and provides a unique flavor to food. However, some harmful Maillard reaction products (MRPs) were inevitably formed during the manufacturing process. Fermentation is a critical step of soy sauce manufacturing and has a significant impact on MRPs formation. Therefore, this study investigated the formation of some characteristic MRPs (e.g., furan, carboxymethyl lysine (CML), 5-hydroxymethylfurfural (5-HMF), α-dicarbonyl compounds) and their correlation with major quality indicators (e.g., free amino acids, reducing sugar, total acid, ammonia nitrogen, total nitrogen, non-salt soluble solids) in low-salt solid-state fermentation soy sauce (LSFSS). The result showed that the levels of furan, CML, and 5-HMF continue to increase during the fermentation process, reaching a maximum after sterilization. Further testing using Person correlation showed that the formation of furan, CML, and 5-HMF in LSFSS was positively correlated with glucose, fructose, α-dicarbonyl compounds, and most of the amino acids, while it was negatively correlated with sucrose and methionine. Among them, the contribution of lysine, valine, isoleucine, leucine, and arginine to furan formation has rarely been reported. Our results provide a good theoretical basis for the control of MRPs during LSFSS fermentation.

Application of tea polyphenols as additives in brown fermented milk: Potential analysis of mitigating Maillard reaction products

Brown fermented milk (BFM) is favored by consumers in the dairy market for its unique burnt flavor and brown color. However, Maillard reaction products (MRP) from high-temperature baking are also noteworthy. In this study, tea polyphenols (TP) were initially developed as potential inhibitors of MRP formation in BFM. The results showed that the flavor profile of BFM did not change after adding 0.08% (wt/wt) of TP, and its inhibition rates on 5-hydroxymethyl-2-furaldehyde (5-HMF), glyoxal (GO), methylglyoxal (MGO), Nε-carboxymethyl lysine (CML), and Nε-carboxyethyl lysine (CEL) were 60.8%, 27.12%, 23.44%, 57.7%, and 31.28%, respectively. After 21 d of storage, the levels of 5-HMF, GO, MGO, CML, and CEL in BFM with TP were 46.3%, 9.7%, 20.6%, 5.2%, and 24.7% lower than the control group, respectively. Moreover, a smaller change occurred in their color and the browning index was lower than that of the control group. The significance of this study was to develop TP as additives to inhibit the production of MRP in brown fermented yogurt without changing color and flavors, thereby making dairy products safer for consumers.

Soy protein isolate-polyguluronate nanoparticles loaded with resveratrol for effective treatment of colitis

Polyguluronate (PG) is an acidic homopolymer of α-(1,4)-l-guluronate separated from alginate. In this study, PG was first grafted with soy protein isolate (SPI) through the Maillard reaction to obtain a new glycoprotein (SPI-PG). Then, this novel glycoprotein was used to prepare nanoparticles to encapsulate the resveratrol (RES). Our results showed that SPI-PG-RES had better pH stability, storage stability and ionic stability than SPI-RES. In vitro digestion experiments showed that the RES bioavailability of SPI-PG-RES was much higher than that of free RES and SPI-RES. Furthermore, the in vitro antioxidant capacity of SPI-PG-RES was much stronger than that of free RES and SPI-RES. In addition, SPI-PG-RES was more effective in preventing the symptoms of DSS-induced colitis than RES and SPI-RES. These results suggested that the protein nanoparticles prepared using SPI-PG were a stable and effective hydrophobic polyphenol carrier and could be applied to food-grade components in functional foods and nutritional supplements.

Control of the Maillard reaction and secondary shelf-life prediction of infant formula during domestic use

To control the Maillard reaction of infant formula (IF) during secondary shelf-life (SSL) and establish an SSL prediction model, the effects of storage temperatures (25°C, 37°C) and relative humidity (RH) levels (32%, 57%, and 75%) on the Maillard reaction products (MRPs) were evaluated. Visible color changes were observed during storage in samples stored at 37°C and not at 25°C. The available lysine loss was the largest, up to 64.14% and 69.40% after 4 weeks of storage at 37°C and 57% RH. At the end of storage, the 5-hydroxymethylfurfural, 3-deoxyglucuronide, fluorescence of advanced Maillard products and soluble Tryptophan (FAST) index, and N^ε -carboxymethyllysine (CML) of two commercial IFs increased by 0.48-3.32, 1.26-12.65, 0.01-4.87, and 0.30-1.05 times, respectively. During storage, the glyoxal content in two commercial IFs tended to increase and then decrease in the range of 0.21-3.43 mg/100 g. The SSL of IFs was predicted using the multivariate accelerated shelf-life test and the Arrhenius model. At 25°C, the estimated SLL of two commercial IFs were 10-9 and 7-6 weeks at 57% and 75% RH, respectively. MRPs and ΔE* could be used as indicators for predicting the SLL of infant formula. PRACTICAL APPLICATION: The results of the study suggested that the increase in storage temperature and humidity during the SSL can promote the MR of IF, which affects the sensory and safety of IF. Therefore, consumers need to focus on controlling storage conditions during the SSL to avoid degradation of IF quality.

Comparative Analysis of Flavor, Taste, and Volatile Organic Compounds in Opossum Shrimp Paste during Long-Term Natural Fermentation Using E-Nose, E-Tongue, and HS-SPME-GC-MS

The present study focused on the determination of color, flavor, taste, and volatile organic compounds (VOCs) changes of shrimp paste fermented for 1, 2, 3, and 8 years by E-nose, E-tongue, and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). During fermentation, the color of shrimp paste turned dark brown with decreases in L*, a*, and b* values. Inorganic sulfide odor was dominant in all fermented samples. The umami, richness, and aftertaste-B reached a maximum in year 3 of fermentation. A total of 182 volatiles, including long-chain alkanes, esters, aldehydes, olefins, ketones, acids, furans, and pyrazines, were detected. Sixteen VOCs including dimethyl disulfide, methional, trimethyl-pyrazine, (E,E)-2,4-heptadienal, benzeneacetaldehyde were selected as flavor markers. Correlation analysis showed that 94 VOCs were related to saltiness while 40, 17, 21, 22, and 24 VOCs contributed to richness, umami, aftertase-B, sourness, and bitterness, respectively. These novel data may help in optimizing fermentation duration to achieve target flavor indicators in opossum shrimp paste production.

Maillard reaction harmful products in dairy products: Formation, occurrence, analysis, and mitigation strategies

Various harmful Maillard reaction products such as lactulosyl-lysine (furosine), furfurals, and advanced glycation end products (AGEs) could be formed during the thermal processing of dairy products, which could lead to various chronic diseases. In this review, the furosine, furfurals, and AGEs formation, occurrence, analysis methods, and toxicological and health aspects in various dairy products were summarized to better monitor and control the levels of harmful Maillard reaction products in processed dairy products. It was observed that all types of dairy products, including raw milk, contain harmful Maillard reaction products, with the highest in whey cheese and condensed milk. High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the common method for the determination of furosine and furfurals and AGEs in dairy products, respectively. However, the simple, rapid, environment-friendly, and accurate methods of determination are still to be developed. Incorporating resveratrol, pectin oligosaccharides (POS) in milk are effective methods to inhibit AGEs formation. This review provides a guide not only for consumers regarding the selection and consumption of dairy products, but also for monitoring and controlling the quality of dairy products.

Integrated metabolomics and lipidomics profiling reveals beneficial changes in sensory quality of brown fermented goat milk

Fermentation and thermal processing can improve the sensory properties of foods. Chemical composition of fermented brown goat milk was investigated using an integrated lipomics and metabonomic method while the effects of changes in chemical composition on sensory quality were also explored. After fermentation, organic acid, peptide and medium- and long-chain fatty acid contents in brown goat milk samples increased significantly. A total of 108 metabolites and 174 lipids related to sensory quality were identified. Heterocyclic compounds, as intermediates of Maillard reaction, modified colour, taste, and aroma, while changes in triglyceride content reduced the impact of off-odour, greatly improving sensory quality of fermented brown goat milk. This study provided new approaches for examining goat milk sensory quality and insights into how these can be modified to further diversify dairy products on the market.

Simultaneously Mitigation of Acrylamide, 5-Hydroxymethylfurfural, and Oil Content in Fried Dough Twist via Different Ingredients Combination and Infrared-Assisted Deep-Frying

The effect of main ingredients (wheat flours, polyol sweeteners, and frying oil) and infrared-assisted deep-frying on the acrylamide, 5-hydroxymethylfurfural (HMF), oil content, and physicochemical characteristics of fried dough twist (FDT) were investigated. The amount of acrylamide and HMF produced in FDT made with low-gluten flour is significantly lower than that of flour with high gluten content. Among polyol sweeteners, maltitol causes the greatest reduction in acrylamide and HMF in FDT. Moreover, the oil content of FDT was significantly reduced by optimizing the infrared-assisted deep-frying process. At last, compared with deep-frying FDT made of sucrose, infrared-assisted deep-frying FDT made of maltitol reduced acrylamide, HMF, and oil content by 61.8%, 63.4%, and 27.5%, respectively. This study clearly showed that the ingredients, flour and polyol sweeteners used to process FDT are the two major determinants of the formation of acrylamide and HMF in FDT, and infrared-assisted deep-frying can significantly affect the oil content in FDT. Simultaneously, the mitigation of the acrylamide, HMF, and oil content in FDT can be achieved by using low-gluten flour and maltitol in the ingredients, combined with infrared-assisted deep-frying.

Carnosic acid depends on glutathione to promote mitochondrial protection in methylglyoxal-exposed SH-SY5Y cells

Methylglyoxal (MG) is an endogenously produced toxicant that induces mitochondrial dysfunction leading to impaired redox biology homeostasis, bioenergetics collapse, and cell death in mammalian cells. However, MG toxicity is particularly relevant to neurons and glia given their chemical and metabolic characteristics. Here, we have investigated whether a pretreatment with carnosic acid (CA) would be able to promote mitochondrial protection in human neuroblastoma SH-SY5Y cells exposed to MG. We found that a pretreatment with CA at 1 μM for 12 h prevented the MG-induced lipid peroxidation and protein carbonylation and nitration in the membranes of mitochondria obtained from the SH-SY5Y cells. CA also prevented the MG-elicited Complexes I and V dysfunction, adenosine triphosphate (ATP) levels decline, and loss of mitochondrial membrane potential (MMP). Moreover, CA also reduced the mitochondrial production of the radical anion superoxide (O₂^-•) in the MG-challenged cells. We found that CA upregulated the synthesis of glutathione (GSH) by increasing the activity of the γ-glutamylcysteine ligase (γ-GCL). Inhibition of the GSH synthesis by buthionine sulfoximine (BSO) abolished the CA-induced mitochondrial protection. Besides, inhibition of the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway, as well as silencing of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), suppressed the CA-stimulated protection and the synthesis of GSH. Thus, CA promoted mitochondrial protection by a PI3K/Akt/Nrf2/γ-GCL/GSH axis in MG-treated SH-SY5Y cells.

Shift of Volatile Organic Compounds (VOCs) in Gluten-Free Hemp-Enriched Sourdough Bread: A Metabolomic Approach

Hemp seed flour represents a potential ingredient for protein enrichment of gluten-free bakery products, the nutritional value of which could be further increased by fermentation with sourdough or with beneficial lactic acid bacteria strains. In this study, a metabolomic approach was used to evaluate the effect of hemp seed flour addition and sourdough fermentation on the production of flavoring and health-related volatile organic compounds (VOCs) in a gluten-free bread. Multivariate analysis of VOCs provided an in-depth description of the effects of hemp seed flour addition and sourdough fermentation on flavoring and bioactive compounds. In particular, an increased concentration of antimicrobial compounds, a larger spectrum of bioactive VOCs and a typical flavoring profile was evidenced in comparison to standard products. Furthermore, an increase of fermentation metabolites was observed in comparison to a standard dough, relating to abundances of 2-butanone-3-hydroxy, acetic acid, ethanol, and 1,4-butanediol. This study provides new insights on the evolution of flavoring and bioactive hemp seed flour constituents during sourdough fermentation, evidencing their retention in baked goods, and describes a new approach that could guide the formulation of innovative, fermented food with enhanced nutritional value.

Acrylamide and Thermal-Processing Indexes in Market-Purchased Food

Determining acrylamide (AA) content in foods using chromatographic methods is expensive and time-consuming. Therefore, there is a need to develop a simple, economical method for monitoring the content of acrylamide in foods. This study analysed whether there is a relationship between acrylamide levels with some heat-induced parameters, such as 5-hydroxymethylfurfural (HMF) and browning, in order to assess their usefulness in predicting the potential acrylamide levels in market-purchased food. Sixty plant-based food products were tested. The correlation coefficients for AA levels with L*, a* and b* values and HMF content were significant (p < 0.05) for French fries and potato chips. There was no statistically significant correlation between thermal-processing indexes (HMF and colour parameters) and acrylamide levels in commercial bread, breakfast cereals and biscuits. The results indicate that these classical thermal-processing indexes are not directly related to the acrylamide content in commercial cereal-based food and they cannot be indicators of AA level. Thus, the correlation between HMF and colour parameters with acrylamide content depends on the type of food and it is difficult to estimate the amount of AA based on these classical thermal-processing indexes of market-purchased food.

Co-Extraction and Co-Purification Coupled with HPLC-DAD for Simultaneous Detection of Acrylamide and 5-hydroxymethyl-2-furfural in Thermally Processed Foods

Acrylamide and 5-hydroxymethyl-2-furfural (5-HMF) are two of the most abundant compounds generated during thermal processing. A simple method for the simultaneous quantitation of acrylamide and 5-HMF was developed and successfully applied in thermally processed foods. Acrylamide and 5-HMF were co-extracted with methanol and then purified and enriched by an Oasis HLB solid-phase extraction cartridge, simultaneously analyzed by high-performance liquid chromatography and detected with a diode array detector, respectively, at their optimal wavelength. The linear concentration range was found to be 25-5000 μg/L with high linear correlation coefficients (R > 0.999). The limit of detection and the limit of quantitation for acrylamide and 5-HMF were 6.90 μg/L and 4.66 μg/L, and 20.90 μg/L and 14.12 μg/L, respectively. The recovery of acrylamide and 5-HMF in biscuits, bread, Chinese doughnuts, breakfast cereals, and milk-based baby foods was achieved at 87.72-96.70% and 85.68-96.17% with RSD at 0.78-3.35% and 0.55-2.81%, respectively. The established method presents simplicity, accuracy and good repeatability, and can be used for the rapid simultaneous quantitation of acrylamide and 5-HMF in thermally processed foods.