Inhibition of polyphenols on Maillard reaction products and their induction of related diseases: A comprehensive review.

BACKGROUND: Food products undergo a pronounced Maillard reaction (MR) during the cooking process, leading to the generation of substantial quantities of Maillard reaction products (MRPs). Within this category, advanced glycation end products (AGEs), acrylamide (AA), and heterocyclic amines (HAs) have been implicated as potential risk factors associated with the development of diseases. PURPOSE: To explore the effects of polyphenols, a class of bioactive compounds found in plants, on the inhibition of MRPs and related diseases. Previous research has mainly focused on their interactions with proteins and their effects on the gastrointestinal tract and other diseases, while fewer studies have examined their inhibitory effects on MRPs. The aim is to offer a scientific reference for future research investigating the inhibitory role of polyphenols in the MR. METHODS: The databases PubMed, Embase, Web of Science and The Cochrane Library were searched for appropriate research. RESULTS: Polyphenols have the potential to inhibit the formation of harmful MRPs and prevent related diseases. The inhibition of MRPs by polyphenols primarily occurs through the following mechanisms: trapping α-dicarbonyl compounds, scavenging free radicals, chelating metal ions, and preserving protein structure. Simultaneously, polyphenols exhibit the ability to impede the onset and progression of related diseases such as diabetes, atherosclerosis, cancer, and Alzheimer's disease through diverse pathways. CONCLUSION: This review presents that inhibition of polyphenols on Maillard reaction products and their induction of related diseases. Further research is imperative to enhance our comprehension of additional pathways affected by polyphenols and to fully uncover their potential application value in inhibiting MRPs.

Multifaceted analysis of the effects of roasting conditions on the flavor of fragrant Camellia oleifera Abel. seed oil.

Fragrant Camellia oleifera Abel. seed oil (FCSO), produced by a roasting process, is popular for its characteristic aroma. This study investigated the effects of various roasting temperatures (90℃, 120℃, 150℃, 180℃) and durations (20 min, 40 min, 60 min) on the flavor of FCSO by physicochemical properties, hazardous substances, sensory evaluation, and flavor analyses. The results showed that FCSO roasted at 120℃/20 min had a reasonable fatty acid composition with a lower acid value (0.16 mg/g), peroxide value (0.13 g/100 g), p-anisidine value (2.27), dibutyl phthalate content (0.04 mg/kg), and higher 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity (224.51 µmol TE/kg) than other samples. A multivariate analysis of FCSO flavor revealed that the 120℃/20 min group had a higher grassy flavor score (5.3 score) from nonanoic acid and a lower off-flavor score (2.2 score) from 2-methylbutyric acid. The principal component analysis showed that 120℃/20 min could guarantee the best flavor and quality of FCSO. Therefore, this information can guide the preparation of FCSO.

New Insights into the Umami and Sweet Taste of Oolong Tea: Formation of Enhancer N-(1-carboxyethyl)-6-(hydroxymethyl) pyridinium-3-ol (Alapyridaine) in Roasting Via Maillard Reaction.

Roasting is pivotal for enhancing the flavor of Wuyi rock tea (WRT). A study investigated a novel compound that enhances the umami taste of WRT. Metabolomics of Shuixian tea (SXT) and Rougui tea (RGT) under light roasting (LR), medium roasting (MR), and heavy roasting (HR) revealed significant differences in nonvolatiles compounds. Compared LR reducing sugars and amino acids notably decreased in MR and HR, with l-alanine declining by 69%. Taste-guided fractionation identified fraction II-B as having high umami and sweet intensities. A surprising taste enhancer, N-(1-carboxyethyl)-6-(hydroxymethyl) pyridinium-3-ol (alapyridaine), was discovered and identified. It formed via the Maillard reaction, positively correlated with roasting in SXT and RGT. Alapyridaine levels were highest in SXT among the five oolong teas. Roasting tea with glucose increased alapyridaine levels, while EGCG inhibited its formation. HR-WRT exhibited enhanced umami and sweet taste, highlighting alapyridaine's impact on WRT's flavor profile. The formation of alapyridaine during the roasting process provides new insights into the umami and sweet perception of oolong tea.

Asparagine-Glucose Amadori Compounds: Formation, Characterization, and Analysis in Dry Jujube Fruit.

Amadori rearrangement products of asparagine with glucose (Asn-Glc-ARP) were first prepared through Maillard model reactions and identified via liquid chromatography-mass spectroscopy. With the study on the effect of the reaction temperature, pH values, and reaction time, the ideal reaction condition for accumulation of Asn-Glc-ARP was determined at 100 °C for 40 min under pH 7. Asparagine (Asn) was prone to degrade from Asn-Glc-ARP in alkaline pH values within a lower temperature range, while in an acidic environment with high temperatures, deamidation of Asn-Glc-ARP to Asp-Glc-ARP (Amadori rearrangement products of aspartic acid with glucose) was displayed as the dominant pathway. The deamidation reaction on the side chain of the amide group took place at Asn-Glc-ARP and transferred it into the hydroxyl group, forming Asp-Glc-ARP at the end. Considering that lyophilization as pretreatment led to limited water activity, a single aspartic acid was not deamidated from Asn directly nor did it degrade from Asp-Glc-ARP even at 120 °C. The degradation of Asn-Glc-ARP through tandem mass spectrometry (MS/MS) analysis showed the obvious fragment ion at m/z 211, indicating that the stable oxonium ion formed during fragmentation. The structure of Asn-Glc-ARP was proposed as 1-deoxy-1-l-asparagino-d-fructose after separation and purification. Also, the content of Asn-Glc-ARP within dry jujube fruit (HeTianYuZao) was quantitated as high as 8.1 ± 0.5 mg/g.

Study on the structural characteristics and emulsifying properties of chickpea protein isolate-citrus pectin conjugates prepared by Maillard reaction.

Chickpea protein isolate (CPI) typically exhibits limited emulsifying properties under various food processing conditions, including pH variations, different salt concentrations, and elevated temperatures, which limits its applications in the food industry. In this study, CPI-citrus pectin (CP) conjugates were prepared through the Maillard reaction to investigate the influence of various CP concentrations on the structural and emulsifying properties of CPI. With the CPI/CP ratio of 1:2, the degree of graft reached 35.54 %, indicating the successful covalent binding between CPI and CP. FT-IR and intrinsic fluorescence spectroscopy analyses revealed alterations in the secondary and tertiary structures of CPI after glycosylation modification. The solubility of CPI increased from 81.39 % to 89.59 % after glycosylation. Moreover, freshly prepared CPI emulsions showed an increase in interfacial protein adsorption (70.33 % to 92.71 %), a reduction in particle size (5.33 µm to 1.49 µm), and a decrease in zeta-potential (-34.9 mV to -52.5 mV). Simultaneously, the long-term stability of the emulsions was assessed by employing a LUMiSizer stability analyzer. Furthermore, emulsions prepared with CPI:CP 1:2 exhibited excellent stability under various environmental stressors. In conclusion, the results of this study demonstrate that the glycosylation is a valuable approach to improve the emulsifying properties of CPI.

Effect of enzymatic Maillard reaction conditions on physicochemical properties, nutrition, fatty acids composition and key aroma compounds of fragrant rapeseed oil.

BACKGROUND: A new enzymatic hydrolysis-based process inspired by the Maillard reaction can produce strong flavored, high-value rapeseed oil that meets safety requirements. In the present study, the effect of reaction time (10-30 min) and temperature (130-160 °C) on the physicochemical properties, nutritional status, fatty acids composition and key aroma compounds of fragrant rapeseed oil (FRO) was investigated. RESULTS: An increasing reaction time and temperature substantially decreased the total tocopherol, polyphenol and sterol contents of FRO, but increased benzo[a]pyrene content, as well as the acid and peroxide values, which did not exceed the European Union legislation limit. Among the volatile components, 2,5-dimethyl was the main substance contributing to the barbecue flavor of FRO. The 150 °C for 30 min reaction conditions produced a FRO with a strong, fragrant flavor, with high total tocopherol (560.15 mg kg-1 ), polyphenol (6.82 mg kg-1 ) and sterol (790.65 mg kg-1 ) contents; acceptable acid (1.60 mg g-1 ) and peroxide values (4.78 mg g-1 ); and low benzo[a]pyrene (1.39 mg g-1 ) content. These were the optimal conditions for the enzymatic Maillard reaction, according to the principal component analysis. Furthermore, hierarchical cluster analysis showed that reaction temperature had a stronger effect on FRO than reaction time. CONCLUSION: The optimal enzymatic Maillard reaction conditions for the production of FRO are heating at 150 °C for 30 min. These findings provide new foundations for better understanding the composition and flavor profile of FRO, toward guiding its industrial production. © 2023 Society of Chemical Industry.

Black garlic particles as a natural pigment and emulsifier in a Pickering emulsion based low fat innovative mayonnaise: Improved rheology and bioactivity.

Black garlic is rich in brown pigments and Maillard reaction products are known for antioxidant activity and health promoting effects. In the present investigation, we report a facile strategy for fabricating low-fat innovative mayonnaise (IM) using black garlic particles (BGP) as a natural pigment, and a functional ingredient. Whey protein concentrate and high methoxyl pectin at optimized concentrations were utilized for fabricating an IM which served as a control. IM5 and IM10 were ternary composites constituting whey protein, high methoxyl pectin along with BGP (@5 and 10% respectively). The formulation IM10 (BGP @10%) showed high firmness and low spreadability quotient, hence IM5 was taken forward for fabrication for two more variants namely IM-J (using low methoxyl pectin (LMP) from jackfruit peels) and IM-C (LMP from citrus). The effect of BGP and LMP on the functional quality of IM was confirmed through zeta potential, antioxidant activity, textural, rheological, and microscopic evaluation. Fluorescence microscopy confirmed the presence of solid particles over the fat phase of IM, while interaction of pectin and whey proteins was demonstrated through fluorescence emission spectroscopy which clearly displayed stabilization of IM through the formation of Pickering emulsion. Pronounced difference in color and flavor score with BGP established high sensory scores in IM5, IM-J, and IM-C. Rheology supported the stabilizing effects of LMP in IM-J and IM-C in terms of speedy recovery of thixotropy, with recovering storage modulus (G'). Enhanced viscosity of IM-C and IM-J further corroborated the dual effect of LMP and BGP in improving emulsifying and functional quality of IM. Enhanced oxidative stability of IM was established by reduced peroxide and Totox values. Overall our results suggest the promising applications of black garlic as functional ingredient in protein and pectin based Pickering emulsions.

Carbohydrate metabolism dynamic in chlorpropham- and 1,4-dimethylnaphthalene-treated potatoes and its effect on the browning of French fries.

The use of a sprout suppressor is crucial for the use of potatoes beyond their natural dormancy period. The main sprout inhibitor used on a commercial scale, chlorpropham (CIPC), is becoming increasingly limited owing to its toxicity. Therefore, we evaluated the effectiveness of 1,4-dimethylnaphthalene (1,4-DMN) compared to CIPC in controlling sprouting and maintaining the quality of potato, Solanum tuberosum 'Asterix', during cold storage. Treatment with 1,4-DMN reduced fresh weight loss and controlled the number and length of sprouts comparable to CIPC. Compared to the control, both sprouting inhibitors led to higher starch and lower reducing sugar contents, and the tubers retained the recommended quality for industrial processing. After frying, less browning was observed in French fries obtained from 1,4-DMN- or CIPC-treated tubers. We ascertain that 1,4-DMN besides being an efficient sprouting inhibitor and alternative to CIPC, it contributes to maintaining the quality of French fries after cold storage.

Wheat Roll Enhanced by Buckwheat Hull, a New Functional Food: Focus on the Retention of Bioactive Compounds.

Wheat roll enhanced by buckwheat hull was used as a model for determining the retention of bioactive compounds during technological steps. The research included analysis of the formation of Maillard reaction products (MRPs) and retention of bioactive compounds such as tocopherols, glutathione, or antioxidant capacity. About a 30% decrease in the content of available lysine in the roll was observed compared to the value obtained for fermented dough. Free FIC, FAST index, and browning index were highest for the final products. The increase of analyzed tocopherols (α-, ß-,γ-, and δ-T) was noticed during the technological steps, with the highest values found for the roll with 3% of buckwheat hull. A significant reduction in GSH and GSSG content occurred during the baking process. The observed increase in the value of the antioxidant capacity after the baking process may be the result of the formation of new antioxidant compounds.

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.

Physicochemical and structural characterization of whey protein concentrate-tomato pectin conjugates.

BACKGROUND: Protein-pectin conjugates, obtained through a controlled Maillard reaction in blends of precursors, are studied for their contribution to improving the emulsifying and thermal properties of proteins. The objective was to obtain a conjugate between whey protein concentrate (WPC) and non-conventional pectins extracted in acid (acid tomato pectin, ATP) and aqueous medium (water tomato pectin, WTP) from industrialized tomato residues (tomato waste, TW), characterize the conjugates and study their emulsion properties. The Maillard reaction was carried out at 60 °C and 75% relative humidity in blends with 2:1 proportions; 1:1 and 1:2 (mprotein :mpectin ) for 3, 6 and 12 days. Conjugates were compared concerning treated and untreated WPC. RESULTS: The WPC-ATP conjugate showed significant increases in color difference (ΔE). The electrophoresis profile of the conjugates showed diffuse bands of molecular weight between 37 and 250 kDa and a reduction in the intensity of bands characteristic of WPC (α-lactalbumin and ß-lactoglobulin). Thermal analysis showed an increase in the peak temperature and a reduction in the enthalpy change in protein denaturation, associated with the formation of conjugates. The infrared spectroscopy of the conjugates, in the amide III zone (1300-1100 cm-1 ), indicated an increase in the relative peak area associated with the unfolding and exhibition of the hydrophobic zones of the WPC fraction. The emulsions formulated with the conjugates showed a significant increase in the emulsifying stability index (ESI) (P < 0.05) concerning the treated and untreated WPC emulsions. CONCLUSION: The formation of conjugates increased the emulsifying properties and improved the thermal stability of WPC, showing an innovative and alternative food ingredient too. © 2023 Society of Chemical Industry.

Understanding the impact of pectin physicochemical variation on browning of simulated Maillard reaction system in thermal and storage processing.

Maillard reaction browning is one of the quality deterioration in dried fruit products, but how pectin affects Maillard reaction in the fruit drying and storage process is not clear. This study aimed at investigating the mechanism of pectin variation impact on the browning of Maillard reaction by using simulated system (l-lysine, d-fructose and pectin) in thermal (60 °C and 90 °C for 8 h) and storage (37 °C for 14 days) process. Results showed that apple pectin (AP) and sugar beet pectin (SP) significantly enhanced the browning index (BI) of the Maillard reaction system by 0.01 to 134.51 in the thermal and storage processes, respectively, which were methylation degree of pectin-dependent. The pectin depolymerization product participated Maillard reaction by reacting with l-lysine, and increasing the 5-hydroxymethyl furfural (5-HMF) content (1.25-11.41-fold) and Abs420nm (0.01-0.09). It also produced a new product (m/z 225.1245), which finally increased browning level of the system.

Effects of different physical factors on potato protein-chitosan complexes considering Hofmeister series and Maillard reaction.

BACKGROUND: Potato protein possesses strong potential for application in the food industry due to its outstanding nutritional and functional properties. However, the inevitable industrial processing often brings adverse effects. The use of a polysaccharide and protein complex is a promising way to improve the performance of potato protein. This work aimed to investigate the effects of different physical factors on the potato protein/chitosan (PP/CS) complex system. RESULTS: The addition of NaCl was not conductive to the formation of PP/CS complexes, resulting in significantly decreased peak turbidities from 1.29 to 0.75. The effect of different ions on PP/CS system matched with the Hofmeister series in the following order: Li+ > Control > Na+ > K+ ; SCN- > I- > NO3 - > Br- ≈ Control > Cl- > SO4 2- , among which the salting-in ions (Li+ , Br- , NO3 - , I- and SCN- ) tended to promote the formation of PP/CS complexes. The turbidity increased significantly when the reaction temperature rose to 45 °C and above, and peak turbidity was obtained at lower pH values. The PP/CS system reaction at 45 °C led to the highest whiteness value, and the Maillard reaction could occur when the temperature was above 45 °C. CONCLUSIONS: The results of the present study confirmed that different physical factors led to strong influences on PP/CS complexes, especially when considering the Hofmeister series and the Maillard reaction. These findings could have significant implications for the utilization of potato protein in complex food systems. © 2023 Society of Chemical Industry.

Changes in the functional properties of casein conjugates prepared by Maillard reaction with pectin or arabinogalactan.

The aim of this study was to prepare conjugates of casein (CA) with pectin (CP) or arabinogalactan (AG) by the Maillard reaction (wet-heating) and to investigate the effects of CP or AG on the structural and functional properties of casein. The results indicated that the highest grafting degree of CA with CP or AG was observed at 90 °C for 1.5 h or 1 h, respectively. Secondary structure showed that grafting with CP or AG reduced the α-helix level and increased the random coil level of CA. Glycosylation treatment of CA-CP and CA-AG exhibited lower surface hydrophobicity and higher absolute ζ-potential values, further significantly improving the functional properties of CA (e.g., solubility, foaming property, emulsifying property, thermal stability, and antioxidant activity). Accordingly, our results indicated that it is feasible for CP or AG to improve the functional properties of CA by the Maillard reaction.

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.

Clarification of the Mechanism of Inhibiting the Maillard Reaction between Phosphatidylethanolamine and Sugars by Adding Fatty Acid Calcium Salts.

Lecithin is known to undergo heat induced deterioration by the Maillard reaction between 1 mol of any sugar, except 2-deoxy sugar, and 2 mol of phosphatidylethanolamine (PE). However, we have previously reported that adding fatty acid metal salts can inhibit heat deterioration of soybean lecithin (SL). To clarify the mechanism of inhibition, 1,2-di-O-stearoyl-sn-glycero-3-phosphatidylethanolamine (DSPE), d-glucose, and calcium stearate or calcium decanoate were heated in octane. When DSPE and d-glucose with calcium stearate or calcium decanoate were heated in the octane, the heat deterioration of DSPE was significantly inhibited, and no increase in UV absorption at 350 nm was observed. From these reactant solutions, one compound having a phosphate group and no primary amine was isolated, and NMR spectra confirmed that two molar of stearic acid derived from DSPE were coordinated to the amino group and phosphate group of DSPE. Therefore, we concluded that adding fatty acid metal salts reduced the nucleophilic reactivity of the amino group of PE and inhibited the Maillard reaction with sugars because two molar of fatty acid derived from PE coordinated to the amino group and phosphate group of PE.

Investigations on color and flavor formed by roasting sesame polysaccharide-protein mixtures.

Roasting is an important operation to produce attractive colors and distinctive flavors during the production of sesame oil. To investigate the contributions of macromolecules to the color and flavor during roasting sesame seeds, water-soluble polysaccharides (WSP) and chelator-soluble polysaccharides (CSP) sequentially extracted from sesame hull were mixed with sesame protein isolate (SPI) at different ratios (1:1, 1:2, and 2:1, w/w), then the mixtures were roasted at 180 °C for 35 min. Results showed that WSP, CSP, and SPI degraded approximately at 150 °C and SPI had the highest thermal stability. According to monosaccharide/amino acid analysis, glucose and galacturonic acid showed the highest reduction rates, as well as lysine and arginine. CSP + SPI mixtures showed greater reactivity than WSP + SPI mixtures, resulting in a darker color and many more Maillard reaction products. The predominant volatiles of roasted WSP/CSP + SPI mixtures were aldehydes and heterocyclic compounds identified by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME/GC-MS). This work provides some new information about flavor and color development during roasting sesame seeds.

Effect of milk fat and its main fatty acids on oxidation and glycation level of milk.

Milk is a highly nutritional food rich in protein and fat that is prone to deterioration by oxidation and glycation reactions at storage and processing. In this study, glycation products and lipid oxidation products contents in skim milk, whole milk, and milk fat simulation groups were determined to evaluate the effect of milk fat components on glycation at 120 °C for 60 min. The increase rate of carbonyl compound, main advanced glycation end products (AGEs) levels, and glycation sites number of α-casein and ß-casein are higher in whole milk than that in skim milk, indicating that milk fat promoted protein glycation significantly. In milk fat simulation groups, oleic acid and linoleic acid (LA) were added to milk fat in skim milk proportionally, promoting the formation of glycation products; however, palmitic acid had no such effect. LA exhibited strong promotion on AGEs formation. Lipid oxidation radicals, protein carbonyl amine condensation, and carbonyl compound formation were critical factors for milk glycation, according to OPLS-DA results. Therefore, radicals of fat oxidation are speculated to trigger the early glycation, and carbonyl compounds of fat oxidation act as important intermediates of glycation, fat type, form, and its degradation rate, thus play essential roles in milk glycation. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05658-z.

Effect of thermal process on the key aroma components of green tea with chestnut-like aroma.

BACKGROUND: Chestnut-like aroma is one of the unique qualities of Chinese green tea and has become an important factor influencing consumer decisions. However, the chemical formation mechanism of chestnut-like aroma during green tea processing remains unclear. In this study, the dynamic changes of key components contributing to chestnut-like aroma and their precursors were analyzed in fresh leaves, fixation leaves, first baking tea leaves, and green tea. RESULTS: The thermal process had an important effect on volatile components in tea leaves, causing a significant decrease of alcohols and esters and a significant increase of ketones, acids, phenols, and sulfur compounds. Furthermore, 31 volatiles were identified as the key odorants responsible for chestnut-like aroma of green tea, including dimethyl sulfide, methyl isobutenyl ketone, 2-methylbutanal, 2,4-dimethylstyrene, d-limonene, methyl 2-methylvalerate, linalool, decanal, longifolene, phenylethyl alcohol, l-α-terpineol, jasmone, and so on. And the majority of these odorants were only formed in the drying stage. Additionally, isoleucine, theanine, methionine, and glucose were found to be involved in the formation of chestnut-like aroma of green tea. CONCLUSION: The drying process played a vital important role in the formation of chestnut-like aroma of green tea. © 2022 Society of Chemical Industry.

Phospholipidomics and quantum chemistry calculation unravel the changes in phospholipid molecules of flaxseed oil during roasting.

Roasting flaxseed significantly improves the antioxidant activities and flavor of its oil; however, the effect of roasting on phospholipid molecules in flaxseed oil is limited. Herein, on the basis of phospholipidomics and quantum chemistry calculation, phospholipidome in raw, light, and dark roasted flaxseed oils and their changes were systematically explored and compared. Seventy individual phospholipid molecules were detected in raw and roasted flaxseed oils. After light roasting, major classes of phospholipid molecules including phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol increased 11.43-, 36.62-, and 67.88-fold, respectively. PE exhibited 92.06 % reduction after dark roasting. The model reaction showed that the main reaction of PE was the Maillard reaction during roasting. Quantum chemistry calculation demonstrated that the reaction energy barriers of the Maillard reaction (96.81 kJ/mol) was much lower than the hydrolysis (188.84 kJ/mol) for PE. The study is expected to provide new insight into the change mechanism of PE during flaxseed processing.