Characterization of antioxidant activity and volatile compounds of Maillard reaction products derived from different peptide fractions of peanut hydrolysate

Integration of lipidomics and flavoromics reveals the lipid-flavor transformation mechanism of fish oil from silver carp visceral with different enzymatic hydrolysis

Lipidomics and volatile organic compounds (VOCs) of fish oil from silver carp visceral hydrolyzed by papain, alkaline protease, pepsin, neutral protease, flavor protease, trypsin, and complex protease were investigated to explore the lipid-flavor transformation mechanism. Our results showed that diglycerol (DG, 18:4/16:1, 18:3/18:3, 16:0/18:3)/fatty acids (20:4) in glycerides and phosphatidylethanolamine (PE, 4:0/18:2)/phosphatidylglycerol (8:0e/10:3) in phospholipids could be used as markers to distinguish fish oil by different enzymolysis. A total of 130 and 36 VOCs were detected in fish oil using GC-MS and GC-IMS, respectively, including 11 key VOCs, namely 1-octen-3-ol, 1-heptanol, eugenol, (E)-2-decenal, (E, E)-2,4-heptadienal, (E, E)-2,4-decadienal, (E)-2-nonenal, benzene acetaldehyde, and 2,3-pentanedione. Moreover, the correlation analysis showed that 1-octen-3-ol, octanal, nonanal, and benzene cetaldehyde, hold significant positive correlations with the DG (16:0/18:3), DG (18:4/16:1), and PE (4:0/18:2). Conclusively, DG and PE, rich in polyunsaturated fatty acids, may be essential precursors for forming key fish oil flavors during enzymolysis extraction.

Maillard reaction products derived from xylose-phosphatidylethanolamine: Potential anti-oxidative substances from hot-pressed flaxseed oil

Hot-pressed flaxseed oil is favored in Northwest China as cooking oil due to its flavor and oxidative stability. The mechanism of enhancing oxidation stability of hot-pressed flaxseed oil by neoformed Maillard reaction products (MRPs) remains mysterious. Maillard model reaction between phosphatidylethanolamine (PE) and reducing sugar of flaxseed, glucose (Glu)/fructose (Fru)/xylose (Xyl), was conducted to investigate the antioxidant characteristics of products. MRPs of PE-Xyl had a superior reactivity and anti-oxidative capabilities, which could improve the oxidative stability of flaxseed oil and inhibited the formation of aldehydes in the accelerated oxidation. Phosphatidylethanolamine-linked pyrrolecarbaldehyde (PLP) was the main antioxidant component in MRPs of Xyl-PE by MS and NMR analysis and verification of antioxidant activity. Furthermore, the results of quantum chemical calculation show that the antioxidant activity center of PLP is the pyrrole group. The findings of this study provide insights into the chemical basis underlying the improved oxidative stability of hot-pressed oils.

Dynamic effects of ultrasonic treatment on flavor and metabolic pathway of pumpkin juice during storage based on GC-MS and GC-IMS

In this study, the dynamic effects of ultrasonic treatment (0-400 W) on the volatile flavor compounds of pumpkin juice under different storage periods were investigated systematically using a combination of headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS) techniques. A total of 139 and 46 volatile organic compounds (VOCs) were identified by GC-MS and GC-IMS, respectively. The results indicated that complex changes in volatile components occurred during storage. It was found that the content of key volatile components, such as 2-ethylhexan-1-ol and 1-pentanol, decreased significantly, whereas the content of 1-nonanol and menthol increased in the early stage of storage, resulting in the gradual change of the aroma of pumpkin juice from an initial aromatic fruity aroma to an alcoholic and rancid aroma. In particular, it was noted that the 200 W ultrasonic treatment not only effectively promoted the release of volatile components, but also significantly slowed down the generation of undesirable flavor substances during storage, which had a positive effect on the retention of pumpkin juice flavor. Through multivariate statistical analysis and KEGG enrichment analysis, phenylalanine metabolism was found to play a key role in regulating the formation of volatile flavor compounds, further confirming the potential value of ultrasonic treatment in the preservation and processing of pumpkin juice. This provides important theoretical support and practical guidance for the commercial production and processing technology of pumpkin juice and other fruit and vegetable juices.

Recent Advances in the Mechanisms of Quality Degradation and Control Technologies for Peanut Butter: A Literature Review

As the quality of life continues to improve globally, there is an increasing demand for nutritious and high-quality food products. Peanut butter, a widely consumed and nutritionally valuable product, must meet stringent quality standards and exhibit excellent stability to satisfy consumer expectations and maintain its competitive position in the market. However, its high fat content, particularly unsaturated fatty acids, makes it highly susceptible to quality deterioration during storage. Key issues such as fat separation, lipid oxidation, and rancidity can significantly compromise its texture, flavor, and aroma, while also reducing its shelf life. Understanding the underlying mechanisms that drive these processes is essential for developing effective preservation strategies. This understanding not only aids food scientists and industry professionals in improving product quality but also enables health-conscious consumers to make informed decisions regarding the selection and storage of peanut butter. Recent research has focused on elucidating the mechanisms responsible for the quality deterioration of peanut butter, with particular attention to the intermolecular interactions among its key components. Current regulatory techniques aimed at improving peanut butter quality encompass raw material selection, advancements in processing technologies, and the incorporation of food additives. Among these innovations, plant protein nanoparticles have garnered significant attention as a promising class of green emulsifiers. These nanoparticles have demonstrated potential for stabilizing peanut butter emulsions, thereby mitigating fat separation and oxidation while aligning with the growing demand for environmentally friendly food production. Despite these advances, challenges remain in optimizing the stability and emulsifying efficiency of plant protein nanoparticles to ensure the long-term quality and stability of peanut butter. Future research should focus on improving the structural properties and functional performance of these nanoparticles to enhance their practical application as emulsifiers. Such efforts could provide valuable theoretical and practical insights into the development of stable, high-quality peanut butter, ultimately advancing the field of food science and technology.

Structural and sensory characteristics of ultrasonic assisted wet-heating Maillard reaction products of Giant salamander protein hydrolysates

BACKGROUND

Chinese giant salamander protein hydrolysates (CGSPH) are beneficial to human health as a result of their high content of amino acids and peptides. However, the formation of bitter peptides in protein hydrolysates (PHs) would hinder their application in food industry. The ultrasound assisted wet-heating Maillard reaction (MR) is an effective way to improve the flavor of PHs. Thus, the effect of ultrasonic assisted wet-heating MR on the structure and flavor of CGSPH was investigated in the present study.

RESULTS

The results indicated that the ultrasound assisted wet-heating MR products (MRPs) exhibited a higher degree of graft and more significant changes in the secondary and tertiary structures of CGSPH compared to traditional wet-heating MRPs. Moreover, ultrasound assisted wet-heating MR could significantly increase the content of small molecule peptides and reduce the content of free amino acids of CGSPH, which resulted in more significant changes in flavor characteristics. The changed in flavor properties after MR (especially ultrasound assisted wet-heating MRPs) were mainly manifested by a significant reduction in bitterness, as well as a significant increase in the content of aromatic aldehyde ester compounds such as furan-2-carbaldehyde, butanal, benzaldehyde, furfural, etc. CONCLUSIONS: Ultrasound assisted wet-heating MR between CGSPH and xylose could be a promising way to improve the sensory characteristics of CGSPH. © 2024 Society of Chemical Industry.

Discovery and mechanistic analysis of a novel source protein glutaminase PG5 and its potential application

In this study, we successfully obtained a novel source protein glutaminase PG5 with specific activity of 10.4 U/mg, good tolerance and broad substrate profile through big data retrieval. Structural analysis and site-directed mutagenesis revealed that the catalytic pocket of Mature-PG5 contained a large number of aromatic amino acids and hydrophobic amino acids, and that Ser72 greatly affects the properties of the catalytic pocket and the affinity of PG5 for the substrate. In addition, molecular dynamics analysis revealed that the opening and closing between amino acid residues Gly65 and Thr66 with Cys164 at the catalytic cleft could affect substrate binding and product release. In addition, PG5 effectively improved the solubility of fish myofibrillar proteins under low-salt conditions while enhancing their foaming and emulsification properties. This study offers valuable insights into the catalytic mechanism of PG5, which will contribute to its future directed evolution and application in the food industry.

Effects of Reducing Sugars on Colour, Amino Acids, and Volatile Flavour Compounds in Thermally Treated Minced Chicken Carcass Hydrolysate

This study investigated the changes in colour, amino acids, and volatile flavour compounds in the enzymatic hydrolysates of chicken carcasses containing different types and amounts of reducing sugars (xylose, arabinose, glucose, and fructose), so as to develop a chicken-based flavouring agent. Before heat treatment at 100 °C for 60 min, the chosen reducing sugars were separately added to the chicken carcass hydrolysate at its natural pH. Pentoses decreased pH more significantly than hexoses in the chicken carcass hydrolysate. The browning degree followed the pattern of pH decline, as pentoses caused more intense browning than hexoses, with xylose dosage having the greatest effect on the colour changes (ΔE). Fructose addition notably reduced free amino acids (FAAs) and cystine contents. Furthermore, phenylalanine decreased with increasing dosages of arabinose, xylose, and fructose. Glutamic acid content decreased significantly with fructose addition but showed insignificant changes with xylose. At the same dosage, the addition of pentoses resulted in the production of more sulphur-containing volatile compounds like methional, 2-[(methylthio) methyl] furan, and dimethyl disulphide than hexoses. Methional and furfural, which provide a roasted, savoury flavour, were produced by adding more xylose. Heat treatment with xylose also removed hexanal, the main off-odourant.

Nonenzymatic glycation as a tunable technique to modify plant proteins: A comprehensive review on reaction process, mechanism, conjugate structure, and functionality

Plant proteins are expected to become a major protein source to replace currently used animal-derived proteins in the coming years. However, there are always challenges when using these proteins due to their low water solubility induced by the high molecular weight storage proteins. One approach to address this challenge is to modify proteins through Maillard glycation, which involves the reaction between proteins and carbohydrates. In this review, we discuss various chemical methods currently available for determining the indicators of the Maillard reaction in the early stage, including the graft degree of glycation and the available lysine or sugar, which are involved in the very beginning of the reaction. We also provide a detailed description of the most popular methods for determining graft sites and assessing different plant protein structures and functionalities upon non-enzymatic glycation. This review offers valuable insights for researchers and food scientists in order to develop plant-based protein ingredients with improved functionality.

Functional Proteins from Biovalorization of Peanut Meal: Advances in Process Technology and Applications

Environmental costs associated with meat production have necessitated researchers and food manufacturers to explore alternative sources of high-quality protein, especially from plant origin. Proteins from peanuts and peanut-by products are high-quality, matching industrial standards and nutritional requirements. This review contributes to recent developments in the production of proteins from peanut and peanut meal. Conventional processing techniques such as hot-pressing kernels, use of solvents in oil removal, and employing harsh acids and alkalis denature the protein and damage its functional properties, limiting its use in food formulations. Controlled hydrolysis (degree of hydrolysis between 1 and 10%) using neutral and alkaline proteases can extract proteins and improve peanut proteins' functional properties, including solubility, emulsification, and foaming activity. Peanut proteins can potentially be incorporated into meat analogues, bread, soups, confectionery, frozen desserts, and cakes. Recently, pretreatment techniques (microwave, ultrasound, high pressure, and atmospheric cold plasma) have been explored to enhance protein extraction and improve protein functionalities. However, most of the literature on physicochemical pretreatment techniques has been limited to the lab scale and has not been analysed at the pilot scale. Peanut-derived peptides also exhibit antioxidant, anti-hypertensive, and anti-thrombotic properties. There exists a potential to incorporate these peptides into high-fat foods to retard oxidation. These peptides can also be consumed as dietary supplements for regulating blood pressure. Further research is required to analyse the sensory attributes and shelf lives of these novel products. In addition, animal models or clinical trials need to be conducted to validate these results on a larger scale.

Variations in volatile flavour compounds in Crataegi fructus roasting revealed by E-nose and HS-GC-MS

Introduction

Crataegi fructus (CF) is an edible and medicinal functional food used worldwide that enhances digestion if consumed in the roasted form. The odour of CF, as a measure of processing degree during roasting, significantly changes. However, the changes remain unclear, but are worth exploring.

Methods

Herein, the variations in volatile flavour compounds due to CF roasting were investigated using an electronic nose (E-nose) and headspace gas chromatography-mass spectrometry (HS-GC-MS).

Results

A total of 54 components were identified by GC-MS. Aldehydes, ketones, esters, and furans showed the most significant changes. The Maillard reaction, Strecker degradation, and fatty acid oxidation and degradation are the main reactions that occur during roasting. The results of grey relational analysis (GRA) showed that 25 volatile compounds were closely related to odour (r > 0.9). Finally, 9 volatile components [relative odour activity value, (ROAV) ≥ 1] were confirmed as key substances causing odour changes.

Discussion

This study not only achieves the objectification of odour evaluation during food processing, but also verifies the applicability and similarity of the E-nose and HS-GC-MS.

Antibacterial Activity and Mechanism of Linalool against Shigella sonnei and Its Application in Lettuce

Shigella sonnei (S. sonnei) infection accounted for approximately 75% of annual outbreaks of shigellosis, with the vast majority of outbreaks due to the consumption of contaminated foods (e.g., fresh vegetables, potato salad, fish, beef, etc.). Thus, we investigated the antibacterial effect and mechanism of linalool on S. sonnei and evaluated the effect of linalool on the sensory quality of lettuce. The minimum inhibitory concentration (MIC) of linalool against S. sonnei ATCC 25931 was 1.5 mg/mL. S. sonnei was treated with linalool at 1× MIC for 30 min and the amount of bacteria was decreased below the detection limit (1 CFU/mL) in phosphate-buffered saline (PBS) and Luria-Bertani (LB) medium. The bacterial content of the lettuce surface was reduced by 4.33 log CFU/cm² after soaking with linalool at 2× MIC. Treatment with linalool led to increased intracellular reactive oxygen species (ROS) levels, decreased intracellular adenosine-triphosphate (ATP) content, increased membrane lipid oxidation, damaged cell membrane integrity, and hyperpolarized cell membrane potential in S. sonnei. The application of linalool to lettuce had no effect on the color of lettuce compared to the control. The sensory evaluation results showed that linalool had an acceptable effect on the sensory quality of lettuce. These findings indicate that linalool played an antibacterial effect against S. sonnei and had potential as a natural antimicrobial for the inhibition of this foodborne pathogen.

Chemical Properties of Peanut Oil from Arachis hypogaea L. 'Tainan 14' and Its Oxidized Volatile Formation

Arachis hypogaea L. ‘Tainan 14’ has purple skin characteristics. This study investigated the effects of different materials (shelled or unshelled peanuts) and temperatures (120 or 140 °C) on the properties of extracted peanut oil. The results show that its antioxidant components (total flavonoid, α−tocopherol, and γ-tocopherol) and oxidative stability were mainly affected by the roasting temperature (p < 0.05). Fifty-eight volatile compounds were identified by peanut oil oxidation and divided into three main groups during the roasting process using principal component analysis. The volatile formation changes of different materials and temperatures were assessed by agglomerative hierarchical clustering analysis. These results provide useful reference information for peanut oil applications in the food industry.

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.

Preparation and identification of an antioxidant peptide from wheat embryo albumin and characterization of its Maillard reaction products

Wheat embryo albumin (WEA) extracted from wheat embryo possesses multiple effects including antioxidant, anti-inflammatory, and immunoregulatory effects. In this study, a single factor experiment was conducted to determine the optimal enzymolysis conditions of WEA. Five components (F1-F5) were obtained via ultrafiltration, among which F3 (molecular weight 3-5 kDa) displayed the best antioxidant activity. WEA and F3 were characterized by transmission electron microscopy, scanning electron microscopy, circular dichroism spectrum analysis, and amino acid composition tests. Results revealed that F3 significantly increased the contents of β-tablets, aromatic amino acids, and hydrophobic amino acids compared to WEA. LC-MS/MS analysis demonstrated that F3 had more tyrosine and histidine moieties than WEA. Moreover, analysis of the Maillard reaction products (MRPs) showed that F3-MRPs had strong browning strength, ultraviolet absorption, higher number of free amino acids, and umami amino acid ratio compared with WEA. In conclusion, enzymolysis can improve the functional properties of WEA, which broadens the application spectrum of WEA in food and pharmaceutical fields. PRACTICAL APPLICATION: This study provides a new approach for identifying potential antioxidants and developing functional foods from WEA, and broadens the application spectrum of wheat germ resources.

Optimization of Enzymatic Hydrolysis of Perilla Meal Protein for Hydrolysate with High Hydrolysis Degree and Antioxidant Activity

Botanical oils are staple consumer goods globally, but as a by-product of oil crops, meal is of low utilization value and prone to causing environmental problems. The development of proteins in meal into bioactive peptides, such as Perilla peptide, through biotechnology can not only solve environmental problems, but also create more valuable nutritional additives. In the present work, the hydrolysis process of Perilla meal protein suitable for industrial application was optimized with the response surface methodology (RSM) on the basis of single-factor experiments. Alcalase was firstly selected as the best-performing among four proteases. Then, based on Alcalase, the optimal hydrolysis conditions were as follows: enzyme concentration of 7%, hydrolysis temperature of 61.4 °C, liquid-solid ratio of 22.33:1 (mL/g) and hydrolysis time of 4 h. Under these conditions, the degree of hydrolysis (DH) of Perilla meal protein was 26.23 ± 0.83% and the DPPH scavenging capacity of hydrolysate was 94.15 ± 1.12%. The soluble peptide or protein concentration of Perilla meal protein hydrolysate rose up to 5.24 ± 0.05 mg/mL, the ideal yield of which was estimated to be 17.9%. SDS-PAGE indicated that a large proportion of new bands in hydrolysate with small molecular weights appeared, which was different from the original Perilla meal protein. The present data contributed to further, more specific research on the separation, purification and identification of antioxidant peptide from the hydrolysate of Perilla meal protein. The results showed that the hydrolysis of Perilla meal protein could yield peptides with high antioxidant activity and potential applications as natural antioxidants in the food industry.

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.

Effects of sugars on the flavor and antioxidant properties of the Maillard reaction products of camellia seed meals

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MRPs were obtained by heating camellia seed meal hydrolysates, and different sugars.

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The ratio of essential amino acids in R-MRPs was increased and the antioxidant activity was the highest.

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MR could improve the flavor and antioxidant activity of camellia seed meal.

In the present study, camellia seed meal Maillard reaction products (MRPs) were prepared using camellia seed meal protein as a raw material. The effects of MR on protein structure and volatile components of camellia seed meal were investigated by fluorescence, UV absorption, infrared spectroscopy, and gas chromatography-mass spectrometry. Not only the change of amino acid content in MRPs, but also the antioxidant capacity of MRPs and the antioxidant capacity after in vitro digestion were determined. Our result showed that the ratio of essential amino acids in R-MRPs was increased and the antioxidant activity was the highest. For the potential of MRPs as flavoring, our sensory evaluation results showed improved flavor and antioxidant activity of camellia seed meal after MR which can be used as flavoring agents at industrial level.

Sugars Replacement as a Strategy to Control the Formation of α-Dicarbonyl and Furanic Compounds during Cookie Processing

In the last decade, several preventive strategies were considered to mitigate the chemical hazard accumulation in food products. This work aimed to study the effect of different sugars on the development of the main chemical hazard in cookies. For this purpose, model biscuits prepared using sucrose, fructose, and glucose were baked at different temperatures (150, 170, and 190 °C) and for different times (from 5 to 45 min), and the levels of α-dicarbonyl compounds, such as 3-deoxyglucosone (3-DG), glyoxal (GO) and methylglyoxal (MGO), 5-hydroxymethylfurfural (HMF), and furanic aromatic compounds were monitored. The replacement of sucrose in the cookie recipes with monosaccharides had as a consequence the highest accumulation of 3-DG (200-600 times higher), MGO, HMF, and furanic volatile compounds, while the use of sucrose allowed for maintaining the 3-DG, MGO, and HMF levels at less than 10 mg/kg dry matter in cookies for the estimated optimal baking time. Moreover, cookies with sucrose were characterised in terms of volatile compounds, mainly in terms of lipid oxidation products, while cookies with fructose or glucose baked at the highest temperature were characterised almost exclusively by Maillard reaction products, confirming a faster development of this reaction during baking at the studied temperatures.

Recent insights in flavor-enhancers: Definition, mechanism of action, taste-enhancing ingredients, analytical techniques and the potential of utilization

The consumers' demand for clean-label food products, lead to the replacement of conventional additives and redesign of the production methods in order to adopt green processes. Many researchers have focused on the identification and isolation of naturally occurring taste and flavor enhancers. The term "taste enhancer" and "flavor enhancer" refer to umami and kokumi components, respectively, and their utilization requires the study of their mechanism of action and the identification of their natural sources. Plants, fungi and dairy products can provide high amounts of naturally occurring taste and flavor enhancers. Thermal or enzymatic treatments of the raw materials intensify taste and flavor properties. Their utilization as taste and flavor enhancers relies on their identification and isolation. All the above-mentioned issues are discussed in this review, from the scope of listing the newest trends and up-to-date technological developments. Additionally, the appropriate sensory analysis protocols of the naturally occurring taste-active components are presented. Moreover, future trends in using such ingredients by the food industry can motivate researchers to study new means for clean-label food production and provide further knowledge to the food industry, in order to respond to consumers' demands.

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.

The Preparation and Identification of Characteristic Flavour Compounds of Maillard Reaction Products of Protein Hydrolysate from Grass Carp (Ctenopharyngodon idella) Bone

This study aims at preparing the Maillard reaction products of protein hydrolysate from grass carp (Ctenopharyngodon idella) bone and identifying its characteristic flavour compounds. Meanwhile, bioactivities and amino acids composition of hydrolysates and its Maillard reaction products were compared with the thermal degradation reaction as one positive control. Single factor experiment was applied to optimize the enzymolysis parameters of grass carp bone protein using flavourzyme, under which the highest degree of hydrolysis (40.1%) was obtained. According to the response surface methodology, the top predicted value (70.45%) of degree of graft of Maillard reaction was obtained with initial pH of 7.07, temperature of 118.33°C, and time of 1.75 h. Moreover, the results of Maillard reaction products illustrated a significant increase in DPPH radical scavenging activity ( $p<0.05$ ) compared to that of hydrolysate and its thermal degradation products, which was accompanied by the decreased ACE inhibitory activity. Besides, the umami-sweet taste amino acid ratio in free amino acids of Maillard reaction products climbed considerably compared to those of hydrolysate and its thermal degradation products, which proved that Maillard reaction is an effective way to improve the flavour taste of protein hydrolysate. The GC-MS results showed that 37, 40, and 62 kinds of volatile compounds were detected in hydrolysate, thermal degradation products, and Maillard reaction products, respectively. The Maillard reaction products contained more flavour volatile compounds of aldehydes, alcohol, ketone, pyrazine, and other compounds that contribute to pleasant aromas. These results suggested that the grass carp bone protein hydrolysate after Maillard reaction could potentially have a wide range of applications as antioxidant and flavour substances.

Mass Spectrometry-Based Flavor Monitoring of Peruvian Chocolate Fabrication Process

Flavor is one of the most prominent characteristics of chocolate and is crucial in determining the price the consumer is willing to pay. At present, two types of cocoa beans have been characterized according to their flavor and aroma profile, i.e., (1) the bulk (or ordinary) and (2) the fine flavor cocoa (FFC). The FFC has been distinguished from bulk cocoa for having a great variety of flavors. Aiming to differentiate the FFC bean origin of Peruvian chocolate, an analytical methodology using gas chromatography coupled to mass spectrometry (GC-MS) was developed. This methodology allows us to characterize eleven volatile organic compounds correlated to the aromatic profile of FFC chocolate from this geographical region (based on buttery, fruity, floral, ethereal sweet, and roasted flavors). Monitoring these 11 flavor compounds during the chain of industrial processes in a retrospective way, starting from the final chocolate bar towards pre-roasted cocoa beans, allows us to better understand the cocoa flavor development involved during each stage. Hence, this methodology was useful to distinguish chocolates from different regions, north and south of Peru, and production lines. This research can benefit the chocolate industry as a quality control protocol, from the raw material to the final product.

Ultrasound microwave-assisted enzymatic production and characterisation of antioxidant peptides from sweet potato protein

Herein, we investigated the effects of ultrasound microwave (UM)-assisted hydrolysis using Alcalase (ALC), Flavourzyme (FLA), and their combination (ALC + FLA), on the production of sweet potato protein hydrolysates (SPPH). UM-assisted enzymatic hydrolysis significantly increased the degree of hydrolysis of SPPH compared with untreated (UN) samples. Fractions with differences in molecular weight (MW) of >10, 3-10, and < 3 kDa in SPPH from UM-assisted ALC, FLA, and ALC + FLA hydrolysis displayed higher antioxidant activities than those from UN samples. MW < 3 kDa fractions of SPPH from UM-assisted ALC and ALC + FLA hydrolysis treatments presented much stronger Fe²⁺-chelating activity (98.48% and 98.59%), ·OH scavenging activity (67.11% and 60.06%), and higher ORAC values (110.32 and 106.32 µg TE/mL), from which diverse peptides with potential antioxidant activities were obtained by semi-preparative HPLC and LC-MS/MS. All identified peptide sequences exhibited at least three potential antioxidant amino acids. Additionally, changes in peptide conformational structure and antioxidant amino acid composition were revealed by structure-activity relationship analysis. Thus, ultrasound microwave treatment has great potential in antioxidant peptides production.

Chemistry and Biofunctional Significance of Bioactive Peptide Interactions with Food and Gut Components

Food-derived bioactive peptides (BAPs) have gained significant interest as functional agents for developing food products with health benefits. To elucidate the underlying bioactivity mechanisms, current research investigates mostly the structure-activity relationship of native peptides. However, peptide structures are highly susceptible to chemical modifications, which can subsequently influence their physiological behaviors and bioactivities. This paper highlights the peptide structure modifications occurring with major food components during processing and the digestive environment of the gut as well as associated changes in peptide properties and biofunctions. Given the modification propensity of peptides, focus should be shifted toward characterizing the nature, biofunctions, gut activity, bioavailability, and safety of the modified peptides toward achieving pragmatic food applications of BAPs.

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.

Impact of roasting conditions on the quality and acceptance of the peanut paste

Roasting is the main processing step performed to improve sensory and conservative properties of peanuts. The objective of this study was to evaluate changes in peanut oil and paste during roasting at different temperatures in a conventional oven (80, 110, 140, 170, and 200°C) and microwave. The increase in roasting temperature promoted reduction of L* value, b* value, and increases of a*, K₂₃₂ , K_270, and acidity. For alpha (α), gamma (γ), and delta (δ) tocopherols, as well as fatty acids, less degradation were observed at the roasting temperature of 140°C. Paste acceptability greater than 70% was achieved with roasting at 140°C. Based on the results, 140°C was the optimal roasting temperature that achieved the best paste acceptance rates with the smallest changes in oil and tocopherol quality parameters.

Sensory attribute and antioxidant capacity of Maillard reaction products from enzymatic hydrolysate of bovine bone marrow extract

Abstract

Maillard reaction and Maillard reaction products (MRPs) are commonly used in food industry, with various sensory and functional properties. Bovine bone marrow extract (BBME) was subjected to enzymatic hydrolysis, followed by the Maillard reaction to enhance its sensory attributes. The antioxidant and antihypertensive activities of BBME, its hydrolysate and their MRPs were assessed. (3⁷) orthogonal experimental design was used to obtain the optimal reaction conditions for generation of MRPs with improved sensory characteristics. The optimal conditions were: processing temperature, 120 °C; processing time, 60 min; xylose concentration, 2.5% (w/v); cysteine concentration, 2%; Vitamin B1, 1.2%; Hydrolyzed vegetable protein, 6%; and sample to liquid ratio, 1:1. The total content of free amino acid in BBME decreased from 86.18 to 25.50 g L^-1 in EH-BBME-MRPs. In addition, EH-BBME and EH-BBME-MRPs contained significantly higher amount of low molecular weight peptides (< 1000 Da; 47.2% and 21.84%, respectively) compared to other samples. They also exhibited enhanced antioxidant activities against DPPH, ABTS and hydroxyl free radicals, and presented improved FRAP activity and reducing power. EH-BBME-MRPs also exhibited higher antihypertensive activity compared to other samples. The results indicate that MRPs derived from BBME hydrolysate are promising components for improving food flavor and also provide health benefits.

Graphic abstract

Changes in Aroma Profile of Shiitake Mushroom (Lentinus edodes) during Different Stages of Hot Air Drying

To clarify the changes in the aroma characteristics of shiitake mushrooms (Lentinus edodes) during hot-air drying, volatile compounds of L. edodes were analyzed using sensory evaluation, electronic nose, and purge and trap combined with gas chromatography-mass spectrometry (PT-GC-MS) at different timepoints of the drying process. Results showed that the sensory and volatile profile changed significantly during the drying process at 60 °C for up to 12 h and the drying process could be divided into three stages: early stage (<2 h), middle stage (2-3.5 h) and late stage (>3.5 h). Volatile compounds in fresh L. edodes consisted mainly of ketones and alcohols. The early stage of drying decreased the concentration of ketone and alcohol compounds and promoted the generation of cyclic organosulfur compounds through a series of enzymatic and non-enzymatic reactions, which mainly contribute to the characteristic odor of shiitake mushroom. Partial least squares-discriminant analysis (PLS-DA) showed that the volatile compounds released after different drying times could be divided into four groups, which have been confirmed by sensory evaluation results. The results suggested that the unique flavor of dried mushrooms is mainly due to the activation of enzymes during the drying process, which act on lentinic acid to produce sulfur-containing heterocyclic compounds. We believe that our study makes a potential contribution to the mushroom cultivation and processing industry to achieve an improvement in sensory quality.

Fractionation of Protein Hydrolysates of Fish Waste Using Membrane Ultrafiltration: Investigation of Antibacterial and Antioxidant Activities

In this study, yellowfin tuna (Thunnus albacores) viscera were hydrolyzed with protamex to obtain hydrolysate that is separated by a membrane ultrafiltration into four molecular size fractions (< 3, 3-10, 10-30, and 30 kDa <). Antibacterial and antioxidant properties of the resulting hydrolysates and membrane fractions were characterized, and results showed that the lowermost molecular weight fraction (< 3 kDa) had significantly the highest (P < 0.05) percentage of bacteria inhibition against Gram-positive (Listeria and Staphylococcus) and Gram-negative (E. coli and Pseudomonas) pathogenic and fish spoilage-associated microorganisms and scavenging activity against DPPH and ABTS radical and ferric reducing antioxidant power among the fractionated enzymatic hydrolysates. These results suggest that the protein hydrolysate derived from yellowfin tuna by-products and its peptide fractions could be used as an antimicrobial and antioxidant ingredient in both nutraceutical applications and functional food.

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.

Elucidation of hulling-induced changes in the aroma and aroma-active compounds of cv. Uzun pistachio (Pistacia vera)

BACKGROUND

The purpose of this study was to define the effects of the hulling process on the aroma and aroma-active composition of cv. Uzun pistachio. Four different hulling processes, namely wet, wet-dry, dry-dry and brine, were applied. In addition, solvent-assisted flavor evaporation (SAFE), simultaneous distillation/extraction (SDE) and purge and trap (P&T) extraction methods were also tested to obtain the best representative aroma extract.

RESULTS

The results revealed that the dry-dry hulling method was the most prominent according to the aroma and aroma-active compounds, and this was especially the case with terpene compounds. The method increased the content of terpenes, pyrazines and total aroma compounds. By application of aroma extract dilution analysis (AEDA), a total of 18 compounds were detected, of which 11 were identified for the first time in the fruit of pistachio. 2,3-Dimethylpyrazine, trimethylpyrazine and 2-ethyl-3,5-dimethylpyrazine were the compounds that had the highest flavour dilution factors.

CONCLUSION

In general, the results of the present research indicated that the hulling method highly affected the overall aroma structure of pistachios. The dry-dry hulling method is therefore suggested to manufacturers to obtain better pistachios with rich and high-quality aroma. © 2019 Society of Chemical Industry.