Change regularity of the characteristics of Maillard reaction products derived from xylose and Chinese shrimp waste hydrolysates

Determination of astaxanthin and astaxanthin esters in three samples of shrimp waste (Parapenaeus longirostris) by high performance liquid chromatography coupled photo-diode array and mass spectrometry detection

The present study aimed to identify the content of astaxanthin and its esterified forms using high-performance liquid chromatography coupled with diode array and atmospheric pressure chemical ionisation mass spectrometry detection in three samples of shrimp waste. The analyses revealed twenty-one astaxanthin derivatives, including astaxanthin in free form, across all three extracts with the highest number of derivatives observed in the head extract. The shell extract had a lower content of astaxanthin and its esterified forms, with monoesterified astaxanthins being the major components, with contents ranging from 0.5-1 mg g-1. On the other hand, in both global waste and head extracts, astaxanthin diesters were found to be the dominant bioactive compounds, with contents ranging from 0.7-5.2 mg g-1 and 10.2-18.2 mg g-1, respectively. Notably, the astaxanthin content extracted from head was significantly higher compared to other extracts, indicating its potential as a valuable source of bioactive compounds.

Characterization of aroma characteristics of silver carp mince glycated with different reducing sugars

The purpose of this study was to investigate the volatile flavor changes in silver carp mince (SCM) gel glycated with different reducing sugars (glucose, L-arabinose, and xylose) based on E-nose, GC-IMS, and sensory evaluation. These results showed that glycation reduced the fishy smell of SCM gel and increased the meaty, toasty, and burnt smell. A total of 10 volatile compounds were considered as characteristic flavor compounds and potential markers. Among them, the main contributors of fishy included hexanal, heptanal, n-nonanal, octanal, etc. Toasty and burnt were mainly related to the production of 3-methylbutanal and furfurol. These results heralded that glycation could be used to improve the volatile flavor of SCM. This research provided a theoretical basis and technical support for glycation in aquatic food flavor quality control, aquatic pre-made food development, and aquatic leisure food processing.

Transforming 'Bonito del Norte' Tuna By-Products into Functional Ingredients for Nutritional Enhancement of Cereal-Based Foods

The fishing industry produces a significant number of by-products. This study explored two methods of transforming these by-products: fish protein hydrolysate (FPH) and Fishmeal (FM). Physicochemical characterization of these products was conducted and their potential inclusion in biscuits was investigated due to the lack of high biological value protein and polyunsaturated fatty acids of this product. The results identified colour disparities between FPH and FM, with FM displaying lower brightness and a more reddish hue. In FPH, there was also a noticeable decrease in polyunsaturated fatty acids, probably associated with the temperature reached in spray-drying. While the incorporation of these by-products in biscuits was feasible, there were challenges, particularly the fishy taste and rancid odour, which were more pronounced in FM biscuits due to the higher fat content. This correlated with the oxidation indexes, such as TBARS and acidity index. Nonetheless, FPH biscuit attributes like typical colour or flavour received positive feedback, attributed to the Maillard reaction. Scanning electron microscopy revealed microstructural differences, which correlated with the results of hardness and fracturability, probably due to the higher fat content in FM. This study revealed the possibility of nutritionally enriching cookies with ingredients derived from fish by-products. However, it would be necessary to go a step further and study alternatives that allow better preservation of saturated fatty acids.

Influence of Pasteurization on Maillard Reaction in Lactose-Free Milk

In order to improve the safety and quality of lactose-free milk (LFM) Maillard reaction products (MRPs), this study used raw cow's milk as raw material and lactase hydrolysis to prepare LFM, which was heat-treated using pasteurization and then placed in storage temperatures of 4 °C, 25 °C and 37 °C to investigate the changes in the Maillard reaction (MR). The results of the orthogonal test showed that the optimal conditions for the hydrolysis of LFM are as follows: the hydrolysis temperature was 38 °C, the addition of lactase was 0.03%, and the hydrolysis time was 2.5 h. Under these conditions, the lactose hydrolysis rate reached 97.08%, and the lactose residue was only 0.15 g/100 g as determined by high-performance liquid chromatography (HPLC), complying with the standard of LFM in GB 28050-2011. The contents of furoamic acid and 5-hydroxymethylfurfural were determined by high-performance liquid chromatography, the color difference was determined by CR-400 color difference meter, and the internal fluorescence spectrum was determined by F-320 fluorescence spectrophotometer. The test results showed that the variation range of furosine in lactose-free milk after pasteurization was 44.56~136.45 mg/100g protein, the range of 5-hydroxymethylfurfural (HMF) was 12.51~16.83 mg/kg, the color difference ranges from 88.11 to 102.53 in L*, from -0.83 to -0.10 in a*, and from 1.88 to 5.47 in b*. The furosine content of LFM during storage at 4, 25, and 37 °C ranged from 44.56 to 167.85, 44.56 to 287.13, and 44.56 to 283.72 mg/100 g protein, respectively. The average daily increase in protein content was 1.18-3.93, 6.46-18.73, and 15.7-37.66 mg/100 g, respectively. The variation range of HMF was 12.51~17.61, 12.51~23.38, and 12.51~21.1 mg/kg, and the average daily increase content was 0.03~0.07, 0.47~0.68, and 0.51~0.97 mg/kg, respectively. During storage at 4 °C, the color difference of LFM ranged from 86.82 to 103.82, a* ranged from -1.17 to -0.04, and b* ranged from 1.47 to 5.70. At 25 °C, color difference L* ranges from 72.09 to 102.35, a* ranges from -1.60 to -0.03, b* ranges from 1.27 to 6.13, and at 37 °C, color difference L* ranges from 58.84 to 102.35, a* ranges from -2.65 to 1.66, and b* ranges from 0.54 to 5.99. The maximum fluorescence intensity (FI) of LFM varies from 131.13 to 173.97, 59.46 to 173.97, and 29.83 to 173.97 at 4, 25, and 37 °C. In order to reduce the effect of the Maillard reaction on LFM, it is recommended to pasteurize it at 70 °C-15 s and drink it as soon as possible during the shelf life within 4 °C.

Fingerprint Analysis of Volatile Flavor Compounds in Crassostrea gigas of Different Ploidy and Gender under High-Temperature Incubation

In this study, diploid, triploid, and tetraploid Crassostrea gigas samples were subjected to gas chromatography and ion mobility (GC-IMS) to identify and analyze volatile compounds and flavor fingerprints under conditions of high-temperature incubation. The GC-IMS technology identified a total of 54 volatile components in C. gigas. The contents of 1-octen-3-ol, butyl pentanoate, p-methyl anisole, and 2-methyl-2-hepten-6-one in male oysters were significantly higher than in females, while the contents of phenylacetaldehyde, benzaldehyde, 2-ethyl-3-methylpyrazine, 2-ethylfuran, and 2,4-hexadienal in female oysters were significantly higher than in males. The contents of non-3-en-2-one-M and 1-pentanol in diploids were significantly higher than in triploids and tetraploids, while the content of 2,4-hexadienal in tetraploids was significantly higher than in diploids and tetraploids. The contents of ethyl acetate, ethyl-2-butenoate, and butanal in tetraploids were significantly higher than those in diploids and triploids. The results of a principal components analysis showed that different samples were relatively independently clustered, allowing the ability to distinguish different oyster samples. The chemical fingerprints of volatile compounds of C. gigas with different ploidy and gender under high-temperature incubation were established, and the volatile substance contours of C. gigas were visualized. The results provide a reference for distinguishing the ploidy and gender of C. gigas under conditions of high-temperature incubation.

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.

Industrial Application of Protein Hydrolysates in Food

Protein hydrolysates, which may be produced by the protein in the middle of the process or added as an ingredient, are part of the food formula. In food, protein hydrolysates are found in many forms, which can regulate the texture and functionality of food, including emulsifying properties, foaming properties, and gelation. Therefore, the relationship between the physicochemical and structural characteristics of protein hydrolysates and their functional characteristics is of significant importance. In recent years, researchers have conducted many studies on the role of protein hydrolysates in food processing. This Review explains the relationship between the structure and function of protein hydrolysates, and their interaction with the main ingredients of food, to provide reference for their development and further research.

Preparation and Characterization of Flavored Sauces from Chinese Mitten Crab Processing By-Products

To achieve high-value utilization of Chinese mitten crab processing by-products, different types of sauces were prepared using crab legs (CLs) and crab bodies (CBs). Two processing methods, enzymatic hydrolysis and enzymatic hydrolysis coupled with the Maillard reaction, were employed to prepare these sauces. An electronic nose (E-nose) and electronic tongue (E-tongue) were used to measure the changes in the taste and odor, an automatic amino acid analyzer was used to measure the amino acid content, and a headspace solid-phase microextraction GC/MS (HS-SPME-GC/MS) was used to analyze the volatile compounds, qualitatively and quantitatively. The results showed that the sour, bitter, and other disagreeable odors of the enzymatic hydrolysis solution (EHS) were reduced following the Maillard reaction; meanwhile, the umami and saltiness were considerably enhanced. The quantity of free acidic amino acids with an umami and sweet taste in the CL and CB sauces after enzymatic hydrolysis and the Maillard reaction was substantially higher than that in the homogenate (HO). The Maillard reaction solution (MRS) produced more volatile compounds than the HO and EHS, such as aldehydes, pyrazines, ketones, etc. These compounds not only impart a unique flavor but also have antioxidant capabilities, making them a prototype for the high-value utilization of crab processing by-products.

Maillard reaction between oligopeptides and reducing sugar at body temperature: The putative anti-glycation agents

Type 2 Diabetes mellitus (T2DM) is one of the most common chronic multifactorial diseases, which is associated with the increased concentration of glucose in the blood. Therefore, the utilization of blood lowering agents is clearly a promising approach which can lead to a suppression of the evaluated blood glucose, and thus curing T2DM and other complication. In this study, we evaluated the glucose lowering effect of a varieties of amino acids (alanine and histidine), dipeptides (carnosine and α-alanine-L-histidine), and tripeptide (glutathione) by reacting with glucose, fructose, and sucrose under 37°C and pH 7.4 to mimic their reaction in physiological condition. By measuring the reduction of reactants and the formation of Maillard reaction products over the course of 21 days’ storage, we found that the glucose lowering effect of carnosine was better than the counterparts. The histidine residue in carnosine may contribute to its glucose lowing effect while β-amino acid β-alanine residue could facilitate the glucose lowering effect of carnosine by maintaining its chemical stability during the storage. These results may open up new avenues for the applications of bioactive peptide carnosine as a natural blood sugar lowering agent to control T2DM.

Insights into flavor and key influencing factors of Maillard reaction products: A recent update

During food processing, especially heating, the flavor and color of food change to a great extent due to Maillard reaction (MR). MR is a natural process for improving the flavor in various model systems and food products. Maillard reaction Products (MRPs) serve as ideal materials for the production of diverse flavors, which ultimately improve the flavor or reduce the odor of raw materials. Due to the complexity of the reaction, MR is affected by various factors, such as protein source, hydrolysis conditions, polypeptide molecular weight, temperature, and pH. In the recent years, much emphasis is given on conditional MR that could be used in producing of flavor-enhancing peptides and other compounds to increase the consumer preference and acceptability of processed foods. Recent reviews have highlighted the effects of MR on the functional and biological properties, without elaborating the flavor compounds obtained by the MR. In this review, we have mainly introduced the Maillard reaction-derived flavors (MF), the main substances producing MF, and detection methods. Subsequently, the main factors influencing MF, from the selection of materials (sugar sources, protein sources, enzymatic hydrolysis methods, molecular weights of peptides) to the reaction conditions (temperature, pH), are also described. In addition, the existing adverse effects of MR on the biological properties of protein are also pointed out.

Effect of glycation on physicochemical properties and volatile flavor characteristics of silver carp mince

The purpose of this study was to explore the effect of glycation on physicochemical properties and volatile flavor characteristics of silver carp mince (SCM). The changes in the degree of grafting, chemical composition, pH, color, total amino acid composition, and volatile flavor compounds of SCM with or without glucose were studied at different heating times. The results showed that the addition of glucose could promote the glycation reaction rate of SCM. Lysine and cysteine were the main amino acids involved in glycation. Glycation enhanced the overall aroma of SCM by accelerating lipid oxidation and Strecker degradation. In conclusion, these results suggest that glycation can enhance the volatile flavor of SCM during thermal processing and can be used as a volatile flavor enhancement technology for the development of protein nutrition food with good flavor from low-value fish.

Vibration mill-assisted complex enzyme hydrolysis for flavoring of freeze-dried sea cucumber powder

This study aims to analyze the flavor differences of freeze-dried sea cucumber powder, processed for different time intervals, under vibration mill-assisted complex enzyme hydrolysis using electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS). The results of principal component analysis by E-nose showed distinction among the four groups of freeze-dried sea cucumber powder (papain-neutral protease (PN) and flavorzyme-neutral protease (FN), processed for 60 and 80 min). The GC-IMS revealed 35 volatile compounds. Subsequently, based on the fingerprint and heat map results, the flavor differences among the samples were clearly distinguished. When compared to the other three groups, the 60-FN group exhibited a greater variety and quantity of volatile compounds such as octanal, heptanal, hexanal, (E, Z)-2,6-nonadienal, and nonanal. The 80-PN group exhibited high amounts of 2-propanone, ethylbenzene, ethyl acetate, and 2,5-dimethylpyrazine. In addition, the vibration mill technique was considered to be a mild enzyme-assisted method. PRACTICAL APPLICATIONS: This study found that different enzyme types and physical technology operation time can affect the different volatile flavor compounds of freeze-dried sea cucumber powder, which can be quickly and effectively be identified by E-nose and GC-IMS technology to improve the flavor and quality of the product, while facilitating the rapid adjustment and development of the industry. Meanwhile, the results of the study could provide a reference for the deep processing and flavor improvement of the sea cucumber industry and make an important contribution to the related literature. In addition, this could also promote the development and application of non-thermal processing technologies such as vibratory mill in the freeze-dried sea cucumber powder industry.

Characteristic flavor of Antarctic krill (Euphausia superba) and white shrimp (Penaeus vannamei) induced by thermal treatment

For the good acceptance and preference of heated shrimp, characteristic flavor composition analysis was necessary. The sensory evaluation, electronic tongue, electronic nose, and gas chromatography-ion mobility spectrometry were employed in this study. After steaming or cooking, the sensory scores of Antarctic krill (KM) and white shrimp (PM) were significantly increased, and five basic tastes were remarkably changed by electronic tongue analysis. Free glycine level increased from 86.48 to 687.12 mg/100 g in PM after steaming, but no significant changes in KM. 5'-nucleotides in heated PM were higher than those in heated KM. In two kinds of shrimp, inorganic ions and lactic acids contents exhibited the decrease trends after cooking, and the response intensities of S4, S5, and S6 showed increase trends after steaming. Nonanal, benzaldehyde, (Z)-3-hexen-1-ol, 1-8-cineol and limonene were produced by thermal treatment. Therefore, characteristic flavor formation was related to thermal treatment.

Response Surface Methodology for Optimization of L-Arabinose/Glycine Maillard Reaction through Microwave Heating

L-Arabinose is a low-calorie sweetener that inhibits sucrose absorption by inhibiting sucrase activity in the human intestinal tract. Response surface methodology (RSM) was applied to optimize the processing parameters of the L-arabinose/glycine Maillard reaction to improve the browning degree and antioxidant activity of Maillard reaction products (MRPs) through microwave heating. The effect of heating time, volume ratio of propylene glycol to double distilled water (ddH2O), and pH on MRPs was evaluated. A change in the volume ratio of propylene glycol to ddH2O, heating time, and pH was associated with a largely changed browning degree and reducing power of the MRPs. RSM predicated optimum conditions that under substrates of L-arabinose/glycine at a ratio of 2 : 1 (w/w) and concentration of 10% (w/v), a heating time of 7.44 min, volume ratio of propylene glycol to ddH2O 0.93, and pH 10.44 were optimum conditions for the Maillard reaction. The predicted data from the optimum reaction conditions coincided well with the experiment results. The main flavor of MRPs is roasted aroma, and the emulsifying ability of MRPs was 0.367 at 500 nm by microwave heating under the optimal Maillard reaction conditions. MRPs derived from L-arabinose and D-glucose had similar activities. However, a slightly greater activity was found with MRP derived from L-arabinose-glycine with a more volume. This study provided a new direction for the development of sweeteners in the future.

Semi-Quantitative and Qualitative Distinction of Aromatic and Flavour Compounds in Charcoal Grilled, Electric Barbecue Grilled, Infrared Grilled and Superheated-Steam Roasted Lamb Meat Patties Using GC/MC, E-nose and E-tongue

This study investigated the influence of four different methods of cooking (charcoal grilling, electric barbecue grilling, superheated-steam roasting and infrared grilling) on the volatile profile of lamb meat patties. The study included the patties of the oyster cut muscle of lambs cooked using charcoal grilling, electric barbecue grilling, infrared grilling and superheated-steam roasting methods. The principal component analysis (PCA) of electric nose data showed a total variance of 73.71%. The e-nose values showed differentiation of the volatiles released from the lamb meat patties. Data of PCA of e-nose and GC-MS revealed good separation between groups. Significance (p < 0.05) was found for the flavour profile values of charcoal-grilled and superheated-steam-roasted samples while the lowest significance was observed between infrared- and electric-barbecue-grilled samples. Saltiness and sourness were higher in superheated-steam-roasted patties than charcoal-grilled samples through e-tongue. The main volatile compound found in all the lamb patties was 2,3-octanedione with a content of 20.43 µg/g–27.83 µg/g. 1-hexanol was highest at 34.74 µg/g in the charcoal-grilled samples while 2,3-octanedione was highest at 35.83 µg/g in superheated-steam-roasted patties.

Effects of Grafting Degree on the Physicochemical Properties of Egg White Protein-Sodium Carboxymethylcellulose Conjugates and Their Aerogels

To improve the mechanical strength and oil-loading performances of egg white protein (EWP) aerogel, the effects of different grafting degrees on the modification of EWP by sodium carboxymethylcellulose (CMC-Na) were investigated. After different dry-heat treatment durations (0, 12, 24, 36, and 48 h), the EWP/CMC-Na conjugates with different grafting degrees (noted as EC0, EC12, EC24, EC36, and EC48, respectively) were obtained. Subsequently, the physicochemical properties of the conjugates, as well as the microstructure, mechanical properties, pore parameters, emulsification properties and oil-carrying properties of the conjugated aerogels, were characterized. The results showed that EC12 (with a grafting degree of 8.35%) aerogel possessed a uniform structure, the largest specific surface area, and the best emulsification performance. This facilitated a more robust aerogel (2.05 MPa) with nearly three times the mechanical strength of EWP aerogel. Moreover, this had a positive influence on the efficient loading and stable retention of oil. EC12 aerogel thus achieved an oil absorption capacity of 5.46 g/g aerogel and an oil holding capacity of 31.95%, and both values were nearly 1.7 times higher than those of EWP aerogel. In general, the EWP-based aerogel with a grafting degree of 8.35% had the best mechanical and oil-loading properties.

Maillard reaction of food-derived peptides as a potential route to generate meat flavor compounds: A review

Plant-based meat analogues (PBMA) are promising foods to address the global imbalance between the supply and demand for meat products caused by the increasing environmental pressures and growing human population. Given that the flavor of PBMA plays a crucial role in consumer acceptance, imparting meat-like flavor is of great significance. As a natural approach to generate meat-like flavor, the Maillard reaction involving food-derived peptides could contribute to the required flavor compounds, which has promising applications in PBMA formulations. In this review, the precursors of meat-like flavor are summarized followed by a discussion of the reactions and mechanisms responsible for generation of the flavor compounds. The preparation and analysis techniques for food-derived Maillard reacted peptides (MRPs) as well as their taste and aroma properties are discussed. In addition, the MRPs as meat flavor precursors and their potential application in the formulation of PBMA are also discussed. The present review provides a fundamental scientific information useful for the production and application of MRPs as meat flavor precursors in PBMA.

Protein Hydrolysis and Glycosylation as Strategies to Produce Bioactive Ingredients from Unmarketable Prawns

The present work shows a procedure to valorize non-commercial boiled shrimp to produce functional ingredients, using a combined treatment based on enzymatic hydrolysis and subsequent glycation under mild conditions. Antioxidant and prolyl endopeptidase-inhibiting activities were determined as a function of hydrolysis and glycation times (0-120 min and 0-180 min, respectively). The reaction products were characterized by determining the degree of hydrolysis, browning, fluorescent compounds, free amino acids, phenol content, Fourier transform infrared spectroscopy (FTIR), and molecular weight of the different fractions obtained. Enzymatic hydrolysis generated hydrolysates with significant antioxidant and prolyl endopeptidase-inhibiting activities. Glycation under mild conditions was used as a strategy to improve the antioxidant and potential nootropic properties of the hydrolysates. During glycation, the free amino acid content decreased, total phenols and fluorescent compounds increased significantly, and low molecular weight melanoidins were formed. The presence of peptide-glucose conjugates was also confirmed by FTIR. Glycation increased the antioxidant activities of the hydrolysates; however, their prolyl-endopeptidase-inhibiting activity was lost. Results showed that compounds with promising antioxidant (hydrolysis and glycation) and potential nootropic (hydrolysis) activities and applications in food systems were obtained from the biotechnological strategy used.

Effect of free amino acids and peptide hydrolysates from sunflower seed protein on the formation of pyrazines under different heating conditions

Most research concerning pyrazine formation in the Maillard reaction is mainly focused on free amino acids (FAAs), but limited information is available on the effect of peptides and proteins. In this study, three Maillard model systems (i.e., glucose and native sunflower seed protein, hydrolyzed peptides or FAAs, respectively) were prepared, and their effect on the formation of volatiles were further compared at different heating conditions by using of headspace solid-phase microextraction equipped with gas chromatography/mass spectrometry (HS-SPME-GC/MS). It was found that pyrazines were the characteristic volatile compounds in tested Maillard models, and with increasing heating temperature and time, the varieties of pyrazine formation significantly increased. The optimum reaction condition for pyrazine formation was at 140 °C for 90 min, which was subsequently applied to all sets of Maillard models. Further analysis showed that the short chain peptides generated by hydrolyzing sunflower seed protein (SSP), especially the molecular weight ranging from 1.2 to 3.0 kDa, significantly promoted the formation of pyrazines, which highlights the important role of peptides in the Maillard reaction models and is expected to intensify aroma promotion in sunflower seed oil.

Exploring the effect of heating temperature and time on the formation of pyrazines; revealing the potential roles of FAAs and hydrolyzed sunflower seed peptides in the Maillard reaction model.

New insights into the flavoring potential of cricket (Acheta domesticus) and mealworm (Tenebrio molitor) protein hydrolysates and their Maillard products

Insect proteins have an earthy-like flavor and have not shown great flavor potential for food applications so far. In this study, insect proteins of cricket Acheta domesticus and mealworm Tenebrio molitor larvae were first enzymatically hydrolyzed using two peptidase preparations (Flavourzyme1000L and ProteaseA "Amano"2SD). Xylose was then added to facilitate Maillard reactions (30 min, T = 98 °C, 1% (w/v) xylose). A comprehensive sensory evaluation showed that both the hydrolysis and the Maillard reactions changed the flavor description of the samples significantly to more complex and savory-like taste profiles (27 descriptors for cricket and 39 descriptors for mealworm protein). In addition, 38 odor-active molecules were identified using gas chromatography-olfactometry (1 alcohol, 5 acids, 11 aldehydes, 5 ketones and 16 heterocyclic compounds). The results showed impressively that the flavoring potential of insect proteins was significantly enhanced with respective processing.

Structural, antioxidant, aroma, and sensory characteristics of Maillard reaction products from sweet potato protein hydrolysates as influenced by different ultrasound-assisted enzymatic treatments

Effects of energy-divergent ultrasound (EDU), energy-gathered ultrasound (EGU), and energy-gathered ultrasound-microwave (EGUM) on structure, antioxidant activities, aroma, and sensory attributes of Maillard reaction products (MRPs) from sweet potato protein hydrolysates (SPPH) were investigated. EGU and EGUM markedly enhanced the Maillard reaction (MR) progress. FTIR results revealed significant peptide structure changes in MRPs as compared to their SPPHs counterparts. EGU-MRPs exhibited the highest percentages in lower MW fractions of 200-3,000 Da, and presented a significantly enhanced ORAC value of 92.10 µg TE/mL (p < 0.05). Besides, EGU-MRPs and EGUM-MRPs showed higher content and quality of aroma compounds than other MRPs, and presented increased umami, sweetness, and sourness attributes, but decreased bitterness (p < 0.05). Their stronger umami taste was highly correlated to 1-naphthalenol, dodecanoic acid, <200, 200-500, 500-1,000 and 1,000-3,000 Da. Thus, EGU and EGUM assisted enzymatic hydrolysis coupled with MR might be promising ways to produce natural flavoring with improved antioxidant activities.

Optimizing food waste hydrothermal parameters to reduce Maillard reaction and increase volatile fatty acid production

The occurrence of the Maillard reaction and melanoidins formation during the hydrothermal treatment of food waste can reduce the yield of volatile fatty acids (VFA); however, few studies have investigated the adverse effects of the Maillard reaction. This study identified the impact of hydrothermal treatment parameters on hydrolysis and melanoidins formation and optimized the hydrothermal treatment conditions to enhance VFA production by minimizing the impact of the Maillard reaction. A response surface methodology was employed to optimize the hydrothermal treatment parameters and VFA production was evaluated. Results showed that temperature, reaction time, and pH were significant interacting factors with respect to hydrolysis and melanoidins formation while the C/N ratio and moisture content of food waste had little impact. The optimal conditions for hydrothermal treatment (temperature of 132 °C, reaction time of 27 min, and a pH of 5.6) enhanced VFA production by 22.1%. Under optimal hydrothermal treatment conditions, a higher initial C/N ratio further increased VFA production.

Characterization of flavor volatile compounds in industrial stir-frying mutton sao zi by GC-MS, E-nose, and physicochemical analysis

This study aims to investigate the flavor changes of industrial stir-frying mutton sao zi, a mutton product popular in the northwest of China, at different stir-frying stages. Electronic nose (E-nose) was used to recognize mutton sao zi odors at different processing time points, and the individual volatile compounds were further identified by the solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). A total of 105 volatile compounds were detected by GC-MS, of which 51 were major volatile compounds. Additionally, GC-MS and E-nose data of the samples were also correlated with the fatty acids, crude composition (moisture, fat, protein), and amino acids. The stir-frying time and temperature may be the critical contributors to different flavors of industrial stir-frying mutton sao zi. The signal intensities of W1S, W1W, W2S, W2W, and W3S sensors positively correlate with protein, fat, and 18 amino acids, but negatively with SFA and moisture. Hence, this study explored the flavor changes of industrial stir-frying mutton sao zi by E-nose and SPME-GC-MS for the first time, providing an insight into the industrial production and flavor control stir-frying machine of stir-frying mutton products with household flavor.

Effects of ultrasound-assisted heating on aroma profile, peptide structure, peptide molecular weight, antioxidant activities and sensory characteristics of natural fish flavouring

This study deals with the production of natural fish flavouring using ultrasound-assisted heating process. The effect of ultrasound pretreatment at different amplitudes (0, 15, 30, and 45%) on the Maillard reaction rate, antioxidant activities, flavour profile, and sensory characteristics of fish flavouring was investigated. Results showed that sonication markedly accelerated the Maillard reaction (MR) rate, as evidenced by the modification of peptide structure, a decrease in pH value, free amino acid content coupled with a rise in browning intensity. Also, ultrasound pretreatment significantly enhanced the antioxidant activities of fish flavouring (p ≤ 0.05). Moreover, sonication increased the type and content of aroma compounds significantly. Sensory analysis revealed that ultrasound pretreatment increased the fish-like and toasty aroma as well as umami and mouthfulness attributes coupled with the reduction of the bitter taste of the fish flavouring. This result was consistent with the GC-MS, electronic nose, cluster, and Partial Least Squares Regression (PLSR) analyses, which clearly showed that ultrasound pretreatment enhanced the fish-like aroma, which was associated with the increase in aldehydes, ketones, alcohols, thiophenes, pyrazine, and furans contents. Thus, it could be concluded that ultrasound pretreatment, coupled with the thermal process, could be a promising process for the production of natural fish flavouring with higher antioxidant activities.

Conception of novel blue crab chitosan films crosslinked with different saccharides via the Maillard reaction with improved functional and biological properties

This work aimed to modify blue crab chitosan-based films through the Maillard reaction (MR) as a novel alternative to improve their functional and biological properties. To this end, different saccharides (glucose (aldohexose), fructose (ketohexose), xylose (aldopentose) and arabinose (aldopentose)), at different weight ratios 0.5, 1.0 and 2.0 % (g/100 g polymer), were studied, and films were heated at 90 °C for 24 h. Based on color changes and browning index measurements, the extent of MR was the highest with aldopentoses, whereas hexoses and particularly ketohexoses, exhibited a relative crosslinking rate. These findings were further reflected with an improvement in treated films mechanical properties and thermal degradation temperatures, and advantageously, barrier properties against UV light and water. In addition, the MR-modified Cs-based films antioxidant activity was interestingly enhanced with mainly aldopentoses. Consequently, MR crosslinked chitosan-based films are promising alternative for active and functional packaging able of food oxidation hindering, especially using aldopentoses.

Process optimization and the relationship between the reaction degree and the antioxidant activity of Maillard reaction products of chicken liver protein hydrolysates

The aim of this study was to optimize the protein hydrolysates from chicken liver with xylose under Maillard reaction (MR) conditions using response surface methodology. The correlation between the browning degree, grafting degree, and the antioxidant activities of the Maillard reaction products (MRPs) was investigated. The optimal reaction conditions were achieved with a reaction temperature of 138.78°C, an initial pH of 7.99, and a reaction time of 93.14 min. The grafting degree (41.98%) and browning degree (2.582) of chicken liver protein hydrolysate MRPs (CLPHM) were notably higher (P < 0.05) than those of protein MRPs (CLPM) and were significantly lower (P < 0.05) than those of sonicated hydrolysate MRPs (SCLPHM). The reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and hydroxyl radical scavenging of CLPM, CLPHM, and SCLPHM were significantly higher (P < 0.01) than those of the protein or hydrolysate substrates. The grafting degree and browning degree of CLPM, CLPHM, and SCLPHM had positive correlations with DPPH and hydroxyl radical scavenging activity. Hence, this study could enhance the added value of chicken liver by exhibiting the enhancements from ultrasound pretreatment and the MR. MRPs could have an effective and potential application in the food industry.

Maillard reaction products derived from food protein-derived peptides: insights into flavor and bioactivity

Food protein-derived peptides serve as food ingredients that can influence flavor and bioactivity of foods. The Maillard reaction plays a crucial role in food processing and storage, and generates a wide range of Maillard reaction products (MRPs) that contribute to flavor and bioactivity of foods. Even though the reactions between proteins and carbohydrates have been extensively investigated, the modifications of food protein-derived peptides and the subsequent impacts on flavor and bioactivity of foods have not been fully elucidated. In this review, the flavor and bioactive properties of food-derived peptides are reviewed. The formation mechanisms with respect to MRPs generated from food protein-derived peptides have been discussed. The state-of-the-art studies on impacts of the Maillard reaction on flavor and bioactivity of food protein-derived peptides are also discussed. In addition, some potential negative effects of MRPs are described.