Maillard Reaction Products Research Articles

Monitoring alkyl pyrazines in roasted hazelnuts by SHS-GC-IMS: IMS response assessment and standardization

Gas chromatography coupled with ion mobility spectrometry (IMS) is an analytical tool which is rapidly becoming widespread in the analysis of food volatiles. Despite this increasing popularity, an assessment of the IMS response for several flavor compound classes is not yet available. This study focuses on alkyl pyrazines and their determination in roasted hazelnut pastes. These Maillard reaction products are crucial to determine the aromatic profile of roasted foods and are suitable markers for industrial roasting monitoring.The instrumental response of 8 alkyl pyrazines was studied using a model matrix and a matrix matching approach. The results showed a relevant effect of the pyrazine ring substitution pattern on the concentration-response curve trends, highlighting that an external standardization of the IMS response is required to make possible relative abundance comparisons between analytes. A response standardization was therefore developed and applied to determine alkyl pyrazines in samples with different roasting intensity and geographical and botanical origin.

Effects of reaction medium type and concentration on the physicochemical properties and flavors of soybean meal hydrolysate-based Maillard reaction products

Tailoring the Maillard reaction (MR) can improve the flavor of soybean meal hydrolysates (SMH). This study showed that the type and concentration of the reaction medium, including glycerol, sorbitol or polyethylene glycol 400 (PEG400) in water, greatly affected the MR (115 °C, 60 min) of SMH with a reducing sugar mixture (d-xylose/d-ribose, 2:1). These media accelerated the MR and enriched greatly the volatile compounds of the MR products (SMH-MRPs), even improving their sensory attributes (e.g. meaty flavor, umaminess and overall liking). Comparisons on MRPs’ pH values, amino acid nitrogen contents, browning intensities, amino acid profiles, peptide size distributions, volatile profiles and sensory attributes revealed that the influences of the reaction media on SMH-MRPs decreased in the order of PEG400-water > glycerol-water > sorbitol-water. An intermediate glycerol or sorbitol concentration made MRPs more desirable. The added medium, key aroma-active compounds, amino acids and sensory descriptors were correlated.

Spray-Drying Impact the Physicochemical Properties and Formation of Maillard Reaction Products Contributing to Antioxidant Activity of Camelina Press Cake Extract.

Spray-drying is one of the most popular techniques in the food industry for converting liquid material from a fluid state into a form of dried particles to produce encapsulated or instant products. Instant products are considered as convenient foods; moreover, the goal of encapsulation is to close the bioactive compounds in a shell, preventing them from being affected by environmental factors. The purpose of this study was to examine the influence of spray-drying conditions, in particular three inlet temperatures, on the physicochemical and antioxidant properties of powders obtained from Camelina Press Cake Extract (CPE). The CPE was spray-dried at 140 °C, 160 °C and 180 °C. The solubility, Carr and Hausner Indexes, tapped densities and water activity of the powders were analyzed. The structural changes were also detected using FTIR spectroscopy. Additionally, the characteristics of the initial and reconstituted samples and their rheological properties were evaluated. The antioxidant potential, total polyphenols and flavonoids content, free amino acids, and the Maillard reaction products contents in the spray-dried powders were also evaluated. The results indicate a cascade of changes between the initial and reconstituted samples, and important changes in the bioactive potential of samples. The inlet temperature significantly influenced the solubility, flowability and particle sizes of the powders, as well as Maillard products formation. The results of the rheological measurements illustrate the changes after the reconstitution of extracts. This study indicates the optimal parameters of CPE spray-drying, those that yield favorable physicochemical and functional values, which may open up a promising path for CPE valorization, indicating its potential and the possibilities of its use.

Changes in structure, functional properties and volatile compounds of Cinnamomum camphora seed kernel protein by Maillard reaction

In this study, Cinnamomum camphora seed kernel protein isolate (CPI)−dextran (DX) model system was used to investigate the impacts of reaction temperatures (70−100 °C) and times (1−4 h) on the structure, functional properties and volatile compounds of Maillard reaction products (MRPs). The formation of MRPs was confirmed by SDS-PAGE, ultraviolet absorption and degree of glycation. Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy showed that the secondary structure of MRPs tended to be more regular than native CPI. Moreover, MRPs had a lower free sulfhydryl group content and higher surface hydrophobicity than native CPI. Fluorescence spectra revealed that the tryptophan residues of CPI were transferred to a more hydrophobic microenvironment. The solubility and emulsifying stability of CPI were decreased, while the foaming activity, foaming stability, emulsion stability and apparent viscosity of CPI were significantly improved (p < 0.05) after Maillard reaction. Furthermore, MRPs exhibited significantly improved (p < 0.05) thermal stability and ABTS+• radical scavenging activity than native CPI, while the DPPH+ radical scavenging activity and ferric reducing power were decreased. In addition, volatile compounds, including aldehydes, ketones, benzenes and esters, were identified in MRPs. These results provide a theoretical guidance for future studies on CPI-DX conjugates.

Bioaccessibility of Maillard Reaction Products from Biscuits Formulated from Buckwheat Flours Fermented by Selected Lactic Acid Bacteria.

The in vitro bioaccessibility of the soluble protein and Maillard reaction products (MRPs) such as furosine (an early indicator of the MR), free FIC (fluorescent intermediate compounds), and FAST index (fluorescence of advanced MRPs and tryptophan), and the level of melanoidins defined by the browning index were analyzed in biscuits formulated from raw and roasted common buckwheat flours fermented by select lactic acid bacteria (LAB). The content of soluble proteins in fermented buckwheat flour and biscuits before and after digestion in vitro was significantly dependent on the LAB applied and the type of flour used and was the highest in the digested biscuits, indicating increased bioaccessibility. Generally, in all analyzed biscuits a lower furosine content was observed as compared to control samples, and its high bioaccessibility was noted after digestion. The free FIC in biscuits was strain-dependent, resulting in low bioaccessibility with the exception of biscuits obtained from both types of flours fermented by Streptococcus thermophilus MK-10. Compared to control biscuits obtained from raw buckwheat flour, the almost twice-increased FAST index was found for samples fermented by L. plantarum IB or Streptococcus thermophilus MK-10. After digestion, at least a fivefold higher value of the browning index was noted in control and tested biscuits, indicating the high bioaccessibility of melanoidins. This study indicates that fermentation of buckwheat flours by selected lactic acid bacteria seems to be a good way to obtain a product with high bioaccessibility of MRPs. However, further research on their functional properties is needed.

Impact of Some Enzymatic Treatments on Acrylamide Content in Biscuits

Since its discovery in many heat-treatment foods in 2002, many efforts have been made to reduce acrylamide levels in foods. Methods to reduce acrylamide levels by reducing Maillard reaction products have been considered. However, baking cookies produces acrylamide, a carcinogenic compound. This study aimed to use a new quantitative index and formula for L-asparaginase, glucose oxidase, their 1:1 blending enzymes, baker’s yeast, and green tea powder (0.5 g/kg wheat flour) at a new proposed temperature of 37 °C for 30 min to reduce acrylamide production in biscuits and bakery products using new indicators such as asparagine reduction (%), the asparagine/acrylamide ratio, acrylamide reduction (%), and the asparagine/reducing sugar ratio. The highest acrylamide concentrations were reduced from 865 mg/kg in the blank sample (BT0) to 260 and 215 mg/kg in the mixed enzyme powder (1:1) (BT3)- and BT4-treated samples, respectively. The biscuit samples treated with 0.5 g/kg L-asparaginase reduced the acrylamide levels by approximately 67.63%, while the BT3 samples showed acrylamide levels of 69.94% and asparagine levels of 68.75% and 47%, respectively, compared with percentage in the untreated sample (blank), 95%. This percentage was 54.16% for the BT4 samples. The results showed that acrylamide was formed during baking, and all treatment samples inhibited its formation, making it possible to produce foods with low levels of acrylamide in starchy foods in the food industry at 37 °C for 30 min and preserving the quality and nutritional value of the final product. It can be used as a specialty food or functional food and protects school-agechildren, as well as youth on campus, from approximately 70–80% of their daily intake of acrylamide.

Sensory attributes and functional properties of maillard reaction products derived from the crassosotrea gigas (Ostrea rivularis gould) enzymatic hydrolysate and xylose system

To improve the flavor of Ostrea rivularis Gould, enzymatic hydrolysis was conducted and xylose-OEH Maillard reaction products were prepared. Then, their physicochemical properties and metabolites were determined by UHPLC-MS-MS, and volatile compounds were determined by GC-MS to investigate the changes. The results showed that His, Gln, Lys, Asp, and Cys were the major amino acids consumed. After being heated at 120 °C for up to 150 min, the DPPH (2,2-Diphenyl-1-picrylhydrazyl) was 85.32 ± 1.35% and the reducing capacity was 1.28 ± 0.12. Both were the highest in the groups. Additionally, 45 volatile compounds, including 2-ethyl-5-methyl-pyrazine and 2-ethyl-3,5-dimethyl-pyrazine, and 678 compounds were identified. We also found that 18 metabolites with significant differences (VIP ≥2) were differential metabolites, which involved lipid oxides and amino acid derivatives. The content of lipids favored the regulation of Maillard products and affected the lower threshold of the flavor of aldehydes, which contributed to the flavor and antioxidant activity. These results suggested the potential of xylose-OEH MRPs as a natural antioxidant for further processing oysters.

Protein interactions during dry and wet heat pre-treatment of skim milk powder (dispersions) and their effect on the heat stability of recombined filled evaporated milk

Skim milk powder (SMP) as well as aqueous dispersions were subjected to dry and wet heat pre-treatment, respectively, to improve the heat stability of recombined filled evaporated milk (RFEM) derived therefrom. However, microrheological analysis revealed that prolonged incubation caused detrimental effects on the heat stability of RFEM, which were thought to be due to protein interactions. SDS-PAGE results indicated that protein aggregation via non-disulfide covalent bonds occurred upon long-time dry or wet heat incubation. This was probably related to some Maillard reaction products, which is sustained by the increase in lactulose and protein carbonyl content. Considerable protein aggregation via disulfide bonds in the serum was found upon wet heat incubation at temperatures of at least 80 °C. Principal component analysis (PCA) revealed that the negative effects of overprocessing on the heat stability of RFEM were predominantly related to protein cross-linking via non-disulfide covalent bonds related to protein carbonylation.

Maillard reaction products between whey powder and water-soluble tempeh protein extract: membrane-based fractionation

Whey powder, an industrial by-product, has the potential to be transformed into functional ingredients using the Maillard reaction. In this study, this chemical reaction occurred between whey powder and tempeh protein extract, resulting in increased antioxidant activity. This study aimed to isolate the Maillard reaction products (MRP) with the best antioxidant capacity using an ultrafiltration (UF) membrane by considering the fouling phenomenon that occurred on the membrane surface and critical flux for the filtration. MRP exhibited an antioxidant capacity of 0.09 mg ascorbic acid equivalent antioxidant capacity/mL, and the fractionation using a 5 kDa MWCO PES membrane showed the highest antioxidant capacity in terms of free radical reduction and metal chelating mechanisms. During MRP filtration, fouling on the membrane surface was observed, which could be attributed to the cake filtration model. The critical flux value was determined to be 4.23 LMH with a corresponding pressure of 0.75 bar. A long-term filtration below the critical flux showed stable performance, but filtration above the critical flux resulted in significant fouling. The permeate antioxidant IC50 value was 4.25 mg/mL. Based on the LC-MS analysis, 1,4-dihydroxy-2-methyl-anthraquinone and ilexin II were found as the potential contributors to the antioxidant activity of MRP. In summary, our study demonstrates that fractionating MRP using UF membrane-based filtration is an effective method for isolating MRP with high antioxidant capacity. Our findings also shed light on the critical flux value and fouling phenomenon during MRP filtration, which are important considerations for scaling up the production process.

Identification and Bioaccessibility of Maillard Reaction Products and Phenolic Compounds in Buckwheat Biscuits Formulated from Flour Fermented by Rhizopus oligosporus 2710

The identification and potential bioaccessibility of phenolic compounds using the highly sensitive micro-HPLC-QTRAP/MS/MS technique and Maillard reaction products (MRPs) in buckwheat biscuits formulated from flours, raw and roasted, fermented by Rhizopus oligosporus 2710 was addressed in this study after in vitro digestion. The content of the analyzed MRPs such as furosine, FAST index, and the level of melanoidins defined by the browning index was increased in the biscuits prepared from fermented flours as compared to the control biscuits prepared from non-fermented ones. After in vitro digestion higher content of furosine was observed in control and tested biscuits providing its high potential bioaccessibility. The fermented buckwheat flours used for baking affected the nutritional value of biscuits in comparison to the control biscuits in the context of the twice-increased FAST index. More than three times higher value of the browning index was noted in control and tested biscuits after digestion in vitro indicating the high bioaccessibility of melanoidins. Our results showed the presence of ten phenolic acids and eight flavonoids in the investigated biscuits. Among phenolic acids, vanillic, syringic, and protocatechuic were predominant while in the group of flavonoids, rutin, epicatechin, and vitexin were the main compounds in analyzed biscuits. Generally, the lower potential bioaccessibility of phenolic acids and higher potential bioaccessibility of flavonoids was found for biscuits obtained from buckwheat flours fermented by fungi compared to control biscuits obtained from non-fermented flours. Fermentation of buckwheat flour with the fungus R. oligosporus 2710 seems to be a good way to obtain high-quality biscuits; however, further research on their functional properties is needed.

Effects of different heat treatments on Maillard reaction products and volatile substances of camel milk.

Camel milk has unique compositional, functional and therapeutic properties compared to cow's milk and also contains many protective proteins with anti-cancer, anti-diabetic and anti-bacterial properties. In this experiment, fresh camel milk was heat-treated at different temperatures and times, and the changes in Millard reaction products were analyzed. Meanwhile, headspace-gas chromatography-ion migration spectrometry (HS-GC-IMS), electronic nose and electronic tongue were used to analyze the changes of volatile components in camel milk after different heat treatments. The results showed that the Maillard reaction was more severe with the increase of heat treatment, and the contents of furosine and 5-hydroxymethylfurfural increased significantly when the heat treatment temperature was higher than 120°C. HS-GC-IMS results showed that the contents of aldehydes and ketones increased obviously with the increase of heat treatment degree. The study clarifies the effects of different heat treatment degrees on Maillard reaction degree and flavor of camel milk, which has practical production guidance significance for the research and industrialization of liquid camel milk products.

Effects of Microwave Heating on Sensory Properties and Antioxidant Activity of Maillard Reaction Products from Enzymatic Hydrolysate of Acetes chinensis

ABSTRACT To study the effect of the Maillard reaction on the flavor and antioxidant activity of the Acetes chinensis hydrolysate after microwave heating, the Acetes chinensis hydrolysate glucose system was heated for 25 min using 100, 200, and 300 W power levels. The results showed that microwave accelerated browning and color change, the products had good flavor and taste characteristics at higher power levels, and the antioxidant activity of the products increased with increasing microwave power/time. These results indicate that the Maillard reaction under the microwave is an effective method of improving the flavor and antioxidant activity of protein hydrolysis products.

The effect of lactose and its isomerization product lactulose on functional and structural properties of glycated casein

Lactulose is an isomer of lactose, formed under thermal processing of milk. Alkaline conditions favor the isomerization of lactose. As reducing sugar, lactose and lactulose could participate in the Maillard reaction and cause protein glycation in milk products. In this study, the influence of lactose and lactulose on the functional and structural properties of glycated casein was investigated. The results demonstrated that compared with lactose, lactulose led to severer changes in molecular weight, more disordered spatial structure and decrease of tryptophan fluorescence intensity of casein. Besides, the glycation degree and advanced glycation end products (AGEs) results suggested that lactulose exhibited stronger glycation ability than lactose due to the higher proportion of open chain in solution. Furthermore, higher glycation degree induced by lactulose resulted in lower solubility, surface hydrophobicity, digestibility and emulsifying capacity of casein-glycoconjugates compared with lactose. The results of this study are essential for tracking the effects of harmful Maillard reaction products on the quality of milk and dairy products.

Flavor changes in Lentinus Edodes enzymatic hydrolysate maillard reaction products with different sugars by gas chromatography‐ion mobility spectrometry

Flavor changes in Lentinus Edodes enzymatic hydrolysate maillard reaction products with different sugars by gas chromatography‐ion mobility spectrometry

Protective influence of heat treatment on the light-induced riboflavin (vitamin B2) degradation in dairy products

Milk is the most important source of riboflavin (Vitamin B2) in many nations. Riboflavin absorbs light in the ultraviolet region and generates singlet oxygen in milk leading to the oxidation of nutrient components and affects the sensory quality of dairy products. The purpose of this work was to elucidate the effect of heat-treatment on the light-induced riboflavin degradation in the model solution of milk bases and milk samples. Although the photo-degradation of riboflavin in all samples was decreased with the increasing of illumination time, the reductions of riboflavin light oxidation were found in all milk model samples and heated milks in according to the formation of Maillard reaction products during heating. The amount of riboflavin remained in control sample (1.5 mg/l riboflavin) was 1.67 % after 2.5 hour illumination. But, it was 34 % and 60 % in the heated lactose and casein solution and milk at 120oC, 45 min, respectively. The increasing of heating time leaded to the increasing of protective ability of milk and model samples against riboflavin photo-degradation. The study clarified that heat treatment of whey proteins, casein and milk might induce the formation of Maillard reaction products that enhanced the protective ability against photo-degradation of riboflavin.

Efficiency of food additives and frying durations in reducing acrylamide and 5-hydroxymethylfurfural formation in tray kadayif dessert

Acrylamide and 5-hydroxymethylfurfural (HMF), end products of Maillard reaction in heat-treated products, are known to have carcinogenic effects on human health. The present work thus investigated the effects of six different food additives (acetic acid, CaCl2, glycine, NaCl, NaHCO3, and sucrose), three different doses (0, 1.5, and 3%, w/w), and two frying durations (30 and 40 min) at 200°C on physicochemical properties of tray kadayif, a famous Turkish dessert. The lowest acrylamide formation was achieved with CaCl2, glycine, and NaCl additives; and the lowest HMF formation was achieved with glycine and NaHCO3 additives. Moreover, increasing frying durations from 30 to 40 min increased acrylamide and HMF levels of the control samples without any additives; but, the effects of frying durations on acrylamide and HMF levels of additive supplemented samples varied with the type and dose of additives. It was concluded that food additives and frying durations could be used as an efficient tool to control Maillard reaction in tray kadayif. The present work provided findings that can be effective in the optimisation of kadayif formulation and process conditions for large-scale industrial production of this popular dessert.

Effect of in vitro digestion and fermentation on antioxidant capacity of weight loss foods and Maillard reaction products content

Cereal snacks and meal replacement shakes are gaining popularity as part of a low-calorie diet. However, some concerns have been risen in relation to their nutrient content and industrial processing. Here we analyzed 74 products, including cereal bars, cereal cakes and meal replacement shakes. We measured furosine and 5-hydroxymethyl-furfural (HMF) due to their relation with industrial processing, mainly thermal treatment, as well as antioxidant capacity after in vitro digestion-fermentation. Most of the products reported a high sugar content, including also large concentrations of HMF and furosine. Small differences were found on antioxidant capacity, although chocolate addition tended to increase the antioxidant power of products. According to our results, antioxidant capacity released after fermentation is higher, which points out to the importance of gut microbes in releasing potentially bioactive compounds. Additionally, we have found alarmingly high concentrations of furosine and HMF, which calls to research into new technologies for food processing to minimize their generation.

Effects of pre-emulsification with whey protein and high temperature sterilisation on texture, functional characteristics and Maillard reaction products of room temperature stored processed cheese

The emulsion and emulsion gel obtained by pre-emulsifying butter with whey protein isolate (WPI) were applied in processed cheese making. The processed cheese was sterilised at 121 °C or pasteurised at 100 °C for 15 min, then stored at 25 °C or 4 °C. The effects of pre-emulsification and pasteurisation on texture, functional characteristics and Maillard reaction of processed cheese during storage were investigated. WPI emulsions significantly improved the texture and inhibited the free oil released from 25 °C stored cheese, while WPI emulsion gels softened the texture and increased the free oil released. Scanning electron microscopy revealed decreased uniformity of cheese microstructure and an increase in the number of large free fat pools after pre-emulsification. Pre-emulsification process slowed the Maillard reaction of refrigerated stored cheese and reduced the content of Maillard reaction products. This study provided a method for improving the texture defects of room temperature stored cheese.

Preparation of probiotic microcapsules using gelatin-xylooligosaccharides conjugates by spray drying: Physicochemical properties, survival, digestion resistance and colonization

Limosilactobacillus fermentum NCU001464 is a probiotic bacterium with anti-hyperuricemia potential, however, its viability decreases during food processing, storage and in the gastrointestinal tract. This study aims to microencapsulate Limosilactobacillus fermentum NCU001464 by spray-drying with Maillard reaction products of gelatin and xylooligosaccharides, heated for various times. Properties of powders and bacterial vitality change during producing, storage and simulated digestion were evaluated. The microcapsules had a low moisture content and the encapsulation appeared effective, however, under scanning electron microscope, cracks were visible on the surface of microcapsules with longer-time heat-treated Maillard reaction products. Heat treatment for 60 min resulted in the highest bacterial viability and adhesion capacity to intestinal epithelial cells after gastrointestinal digestion. After 10 weeks storage at 4 °C and 25 °C, the viable count of MRP-microencapsulated cells was 9.00–6.80 Log CFU/g, more than the recommended dose of 6 Log CFU/mL.

Preparation and antimicrobial mechanism of Maillard reaction products derived from ε-polylysine and chitooligosaccharides

Chitooligosaccharides can be combined with amino acids or polypeptide to form Maillard reaction products (MRPs) with the antibacterial characteristics through Maillard reaction. This research aims to clarify the structure, antimicrobial effect and mechanism against Shewanella putrefaciens (S. putrefaciens) of ε-polylysine and chitooligosaccharides Maillard reaction products (LC-MRPs). The results of intrinsic fluorescence (IF) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, proton nuclear magnetic resonance (1H NMR) spectra and scanning electron microscope (SEM) indicated Maillard reaction occurred between ε-polylysine and chitooligosaccharides. The observation of confocal laser scanning microscopy (CLSM), SEM and growth curves of S. putrefaciens evidenced that LC-MRPs have the strongest antibacterial effects. The leakage of alkaline phosphatase (AKP) and lactate dehydrogenase (LDH) implied that LC-MRPs sabotaged bacterial barrier (cell wall and cell membrane). The changes in content of nucleic acids, reactive oxygen species (ROS) level, lipid peroxidation content (LPO), succinate dehydrogenase (SDH) activity and adenosine triphosphate (ATP) content showed LC-MRPs will affect bacterial genetic gene transcription, material and energy metabolism. Therefore, the LC-MRPs were effective antibacterial agents to inhibit S. putrefaciens, which will help to preserve food with S. putrefaciens as the main spoilage bacteria.