Formation Of Volatile Compounds Research Articles

Transcriptome sequencing and gas chromatography–mass spectrometry analyses provide insights into β-caryophyllene biosynthesis in Brassica campestris

Sesquiterpenes are important defensive secondary metabolites and aroma components. However, limited information is available on the mechanism of sesquiterpene formation and composition in the non-heading Chinese cabbage (NHCC) leaf. Therefore, headspace solid-phase microextraction/gas chromatography–mass spectrometry (HS-SPME/GC–MS) combined with transcriptome analysis was used to study the mechanism of volatile organic compound formation. A total of 26 volatile organic compounds were identified in two NHCC cultivars ‘SZQ’ and ‘XQC’ and their F1 hybrids. Among these, sesquiterpene β-caryophyllene was identified only in ‘XQC’ and F1. Five genes encoding caryophyllene synthase were identified. The candidate β-caryophyllene synthase genes BcTPSa11 and BcTPSa21 had high expression levels only in ‘XQC’ and F1. In addition, several transcription factors of MYB-related, MYB, bHLH, and AP2/ERF families were identified by co-expression, suggesting that they regulate β-caryophyllene biosynthesis. Our results provide a molecular basis for sesquiterpene biosynthesis as well as insights into the regulatory network of β-caryophyllene in NHCC.

The contribution of edible cricket flour to quality parameters and sensory characteristics of wheat bread.

This study evaluated the influence of edible cricket flour (ECF) on the quality parameters and sensory characteristics of wheat bread (WB), including the formation of volatile compounds (VC) and their relationship with emotions (EM) induced for consumers. ECF reduced dough pH, redness, and yellowness. At 5%, ECF increased the porosity of WB (by 7.87%). The quantity of ECF significantly affected WB's specific volume (p=.030), porosity (p=.0001), shape coefficient (p=.0001), and mass loss (p=.023). All WB with ECF had a more intense color and additive odor. Bread samples with 10% and 15% ECF had more intense overall, additive, acidity, and bitterness flavors. However, all WB had similar overall acceptability (OA) and no correlations were found between OA and VC. The EM "happy" and "sad" were expressed more intensely for WB with 15% ECF, and significant correlations were established between the EM "happy" and separate VC. The main VC in WB were ethanol; 1-butanol and 3-methyl; 1-hexanol; estragole; and hexanoic acid. Finally, 5% ECF could be incorporated into the main WB formula without having a negative impact on bread quality. Also, ECF influences VC formation, and separate VC could be related to emotions induced for consumers.

Promoted Formation of Pyrazines and Sulfur-Containing Volatile Compounds through Interaction of Extra-Added Glutathione or Its Constituent Amino Acids and Secondary Products of Thermally Degraded N-(1-Deoxy-d-ribulos-1-yl)-Glutathione.

An Amadori rearrangement product (ARP) derived from ribose (Rib) and glutathione (GSH) was prepared and identified as N-(1-deoxy-d-ribulos-1-yl)-glutathione by ultraperformance liquid chromatography-tandem mass spectrometry and NMR. Thermal treatment of the ARP aqueous solution was conducted, and a relatively high temperature was found to accelerate the degradation of the ARP. The concentration of furans formed at 120 °C was more than 6.39 times that at 100 °C, and especially, the high temperature favored the formation of furfural and 4-hydroxy-5-methyl-3(2H)-furanone through deoxyosone dehydration. The promoting role of extra-added GSH or its constituent amino acids was investigated in the volatile formation during thermal processing of the ARP. Both, the added GSH and its constituent amino acids, could timely capture glyoxal (GO) and methylglyoxal (MGO) to facilitate Strecker degradation, which improved pyrazine formation. Compared with glycine and glutamic acid, cysteine was the most effective extra-added amino acid to react with GO and MGO to produce pyrazine and methylpyrazine. More importantly, the cysteine degraded from extra-added GSH effectively accelerated the generation of sulfur-containing volatile compounds through the reaction of cysteine degradation products with furans and shorter-chain α-dicarbonyl compounds.

Unraveling the contribution of pre-salting duration to microbial succession and changes of volatile and non-volatile organic compounds in Suancai (a Chinese traditional fermented vegetable) during fermentation

Pre-salting is an important pre-treatment during production of Suancai as it provides flavor precursor and microbial community for subsequent fermentation. To investigate the effect of pre-salting duration on fermentation of Suancai, the physicochemical properties, microbial composition, non-volatile and volatile organic compounds profiles of Suancai pre-salted for 1 month (1 M) and 7 months (7 M) were analyzed during fermentation for 30 days. Results showed that 7 M led to higher salt content, faster depletion of reducing sugars, and more titratable acidity. Additionally, more lactic acid and acetic acid, and less umami amino acid (Glu) and GABA were observed in 7 M. Longer pre-salting duration (7 M) promoted formation of mild-flavor volatile compounds, and significantly reduced isothiocyanates with pungent off-flavor. Moreover, 7 M promoted abundance of genera Chromohalobacter, Vibrio and Pichia, while reducing abundance of Lactobacillus, Debaryomyces and Kazachstania throughout fermentation. These results implicated that longer pre-salting duration facilitated more acidic, milder flavor and less pungent off-odor in Suancai. This study provided a perspective for pre-salting as a control point for improving quality of fermented vegetable.

Effect of supercritical carbon dioxide on bacterial community, volatile profiles and quality changes during storage of Mongolian cheese

Mongolian cheese was sterilized by using supercritical carbon dioxide (SC–CO2) treatment at three pressures (10, 15 and 20 MPa) and three temperatures (40, 50 and 60 °C). The optimum SC-CO2 condition (20 MPa and 60 °C) could achieve complete inactivation of bacteria. Preservation of Mongolian cheese was assessed at 25 °C for 20 d by analyzing texture, bacterial communities and volatile compounds, after using SC-CO2 (20 MPa and 60 °C). The results indicated that SC-CO2 treatment could maintain texture stability of Mongolian cheese during storage. High throughput sequencing results showed that Clostridium_sensu_stricto and Lysinibacillus were not detected in the SC-CO2 treated cheese and the total abundance of spoilage bacteria in the SC-CO2 treated cheese was much lower than that in untreated cheese after 20 days storage. Nine core functional bacteria such as Clostridium_sensu_stricto, Lysinibacillus, Pseudoclavibacter, Pseudomonas, Acinetobacter, Lactococcus, Aeromonas, Serratia and Buttiauxella that significantly affected the formation of volatile compounds were identified by Spearman correlation analysis. SC-CO2 treatment decreased the contents of volatile compounds (acids and esters) (p < 0.05), avoiding off-flavors development related to the volatile compounds of excess in Mongolian cheese during storage. Overall, SC-CO2 technology could be used as an effective tool to sterilize Mongolian cheese with minimal quality changes.

Effects of combined carnosine and ultra-high pressure on the inhibition of fishy off-odor of snakehead fillets and the possible mechanism

The effects of combined application of ultra-high pressure (300 Mpa, 900 s) and carnosine on the inhibition of fishy off-odor from snakehead meat were investigated. Results showed that the combination effectively inhibited the formation of fishy volatile organic compounds (VOCs) and trimethylamine (TMA-N). Further studies demonstrated that the reduction of VOCs was mainly due to the inhibition of lipids oxidation based on the antioxidant activity of carnosine and the inactivation of lipoxygenase by UHP. Moreover, the reduction of TMA-N was mainly attributed to the ability of UHP processing to reduce bacterial load, which also extended the shelf-life of snakehead fillets by ∼ 6 days and retarded the production of TVB-N. Additionally, the combined application allowed a better retention of pH, color, and textural quality of the fillets compared with the control. Therefore, the current combination is a promising technique in fishy off-odor removing and better preservation of snakehead meat.

Biotransformation of selenium in the mycelium of the fungus Phycomyces blakesleeanus.

Biotransformation of toxic selenium ions to non-toxic species has been mainly focused on biofortification of microorganisms and production of selenium nanoparticles (SeNPs), while far less attention is paid to the mechanisms of transformation. In this study, we applied a combination of analytical techniques with the aim of characterizing the SeNPs themselves as well as monitoring the course of selenium transformation in the mycelium of the fungus Phycomyces blakesleeanus. Red coloration and pungent odor that appeared after only a few hours of incubation with 10mM Se+4 indicate the formation of SeNPs and volatile methylated selenium compounds. SEM-EDS confirmed pure selenium NPs with an average diameter of 57nm, which indicates potentially very good medical, optical, and photoelectric characteristics. XANES of mycelium revealed concentration-dependent mechanisms of reduction, where 0.5mM Se+4 led to the predominant formation of Se-S-containing organic molecules, while 10mM Se+4 induced production of biomethylated selenide (Se-2) in the form of volatile dimethylselenide (DMSe) and selenium nanoparticles (SeNPs), with the SeNPs/DMSe ratio rising with incubation time. Several structural forms of elemental selenium, predominantly monoclinic Se8 chains, together with trigonal Se polymer chain, Se8 and Se6 ring structures, were detected by Raman spectroscopy.

Fluidized bed roasting of cocoa nibs speeds up processing and favors the formation of pyrazines

Roasting is an important step in cocoa processing causing water loss and generating volatile compounds responsible for chocolate aroma like nitrogen-heterocycles. In this study, the comparison of two techniques, oven roasting, and fluidized bed roasting, in terms of effective water diffusivity (De) and activation energies of formation (Ea) of nitrogen-heterocycles was achieved with cocoa nibs. Fluidized bed roasting, recognized for its energy efficiency and low-footprint synthesis, was 16 times faster than oven roasting. The order of magnitude of De in fluidized-bed-roasted nibs was −8, while it was −9 in the oven-roasted nibs. Moreover, the aw was 50% higher in fluidized-bed-roasted nibs than in the oven-roasted ones. The Ea of nitrogen-heterocycles ranged roughly between 40 and 80 kJ/mol. Those values were lower under fluidized bed roasting than under oven roasting. The more effortless water mobility within fluidized-bed-roasted cocoa demanded lower Ea, and favored the formation of nitrogen-heterocyclics. Industrial relevanceThis study can inspire cocoa manufacturers and equipment designers to pursue the formation of nitrogen-heterocycles during the roasting process of cocoa. It can be done either by adapting and scaling the current fluidized bed coffee roasters to cocoa beans or nibs; or by exploring other alternatives capable of leading enough water diffusivity and water activity in the cocoa nibs, as reported here. These physicochemical conditions undoubtedly boosted the formation of volatile compounds responsible for chocolate aroma, e.g., the pyrazines, without carrying the formation of typical-burn volatile compounds. This natural way of favoring the generation of pyrazines in cocoa nibs could contribute to clean labels by reducing or avoiding the subsequent use of flavorings. The implementation of efficient heat-transfer techniques during roasting, e.g., fluidized bed roasting, could reduce the processing cost and improve sustainability. Studies in the matter of sensory profile, and energy consumption/conversion are called for future research.

Formation of volatile flavor compounds, maillard reaction products and potentially hazard substance in China stir-frying beef sao zi

The effects of stir-frying stages on the formation of flavor volatile compounds, Maillard reaction products (MRPs) and potentially hazardous substances with time in stir-fried beef sao zi were investigated. A total of 122 volatile compounds were identified in beef sao zi after stir-frying. Most of the volatile compounds were produced in the stir-frying fat (SFF) process of beef sao zi. Furosine, fluorescence intensity, Nε-(1-Carboxymethyl)-L-lysine (CML), Nε-(1-Carboxyethyl)-L-lysine (CEL) polyaromatic hydrocarbons (PAHs), heterocyclic aromatic amines (HAAs) and acrylamides (AA) are mainly presented in stir-fried beef sao zi. The furosine peaked at MSF 120 s as the Maillard reaction progressed. The fluorescent compound gradually increased with time during the stir-frying process. The CML and CEL peaked at MSF 120 s. AA reached its maximum in MSF 90 s and then decreased. The quantities and content of HAAs and PAHs were increased by prolonging the stir-frying time, but ended up far lower than the maximum permissible value specified by the Commission of the European Communities. The extended stir-frying promoted MRPs and some hazardous substances, but the content of potentially hazardous substances was still within the safety range for stir-frying beef sao zi.

Formation of Volatile Heterocyclic Compounds and Open-Chain Amides of Theanine in Model Systems with Glucose, Tea Leaves, and Tea Extract under Tea-Roasting Conditions.

Theanine is a non-proteinogenic amino acid found in the tea plant Camellia sinensis. At an elevated temperature (>90 °C), it released two major volatile compounds 1-ethyl-1,5-dihydro-2H-pyrrol-2-one and N-ethylsuccinimide. Other products were identified, including 10 pyrroles and 12 amides/imides. The formation of the two major compounds was proposed to be initiated by the deamination of theanine and through the intermediate α-keto acid. In the presence of glucose, the two major products and many other volatiles from theanine thermal degradation were accelerated and further Maillard reactions occurred. A total of 56 compounds were identified in the model system of theanine and glucose, including 12 amides/imides, 16 pyrazines, 16 pyrroles and other N-heterocycles, and 12 furans and other O-heterocycles. Although most of the reaction products were detected in tea leaves and in their aqueous extract with or without the addition of theanine under the same experiment conditions, imides and amides were considerably suppressed, left only minute amounts, or were even no longer detectable. Pyrazines and pyrroles were also shown at reduced concentrations as a result of the interaction with tea components but to a lesser extent. A total of 16 and 12 pyrazines were identified in the theanine/glucose reaction system and tea leaves/aqueous extract after roasting, respectively. The results indicated that pyrazines and other main volatiles in roasted tea leaves were formed from the Maillard reactions of the aqueous fraction of tea leaves. Theanine participated in the formation of pyrazines in tea leaves under roasting conditions.

Enhancing processed quality of roasted eel with ultrasound treatment: Effect on texture, taste, and flavor

To enhance processed quality, ultrasound treatment was used in eel products processing. This study aimed to investigate the effects of ultrasonic power on the processed quality of roasted eel. Prior to toasting, eel muscle was treated with ultrasonic power from 0 W to 1000 W. Results showed that the highest water content (80.0%) was produced with 600 W ultrasound. Ultrasound above 400 W increases the hardness and chewiness of (p < .05). The SEM results illustrated the application of ultrasound promoted a more porous and homogeneous network. 600 W ultrasound can increase the umami amino acids, and enhance the content of adenosine monophosphate (p > .05) and inosine monophosphate (p < .05). Thiobarbituric acid was increased by ultrasound, especially over 600 W (p < .05). Polyunsaturated fatty acids changed greatly due to the ultrasound treatment (42.50% ~ 38.91%). Samples treated with 400 ~ 600 W had the most abundant volatile organic compounds. In conclusion, ultrasound treatment especially within 600 W enhanced the processed quality of roasted eel. Novelty impact statement This work further investigates effect of ultrasonic power on processed quality of roasted eel in ultrasonic assisted processing, including the influences on texture, taste and flavor. The application of ultrasound helped to obtain a more porous and homogeneous network. Meanwhile, ultrasound treatment can increase protein degradation and lipid oxidation, and finally promote the formation of umami contents and volatile organic compounds.

HALITOSIS ASSESSMENT IN PATIENTS WITH ORTHODONTIC APPLIANCE AND THEIR ASSOCIATION WITH BULLYING

Halitosis is the term used to define the unpleasant odor exhaled through exhaled air, which may be signaling a pathological, physiological or adaptive condition. Most individuals who present this alteration experience personal discomfort, social embarrassment and emotional anguish, which can cause serious disturbances of coexistence, especially in the school environment. The etiology of halitosis is multifactorial, but its main cause comes from the formation of volatile sulfur compounds (VSC) resulting from the proteolytic bacterial action on stagnant organic matter in the oral cavity. The use of orthodontic appliances may be an agent related to the development of this alteration, since it favors the accumulation of organic residues, epithelial desquamation, gingival inflammation, in addition to making local hygiene difficult. Therefore, the present study aims to evaluate the breath of patients with orthodontic appliances and also the possible presence of bullying related to such an event, in young adults aged between 18 and 24 years, students at Universidade Paulista de Brasília. Breath assessment was performed using an organoleptic test (gold standard), which is performed by the examiner’s sense of smell, and a Halimeter® portable monitor, and saliva assessment was performed using a sialometry test, in which the amount of saliva was evaluated. The possible relationship with bullying was assessed through a specific questionnaire. Of the twelve students included in the study, seven presented halitosis when evaluated through the organoleptic test, however, of these seven only two presented parameters compatible with halitosis, when evaluated by the Halimeter®. In relation to bullying, this study showed that it was present in the lives of many respondents, but not necessarily because of breath.

The Impact of Dry Yeast Rehydrated in Different Plasma Treated Waters (PTWs) on Fermentation Process and Quality of Beer.

Yeast plays a key role in the production of alcoholic beverages. Effective fermentation requires appropriate conditions to ensure the production of high-quality beer. The paper discusses the effect of dry brewing yeast (Saccharomyces cerevisiae and Saccharomyces pastorianus) after rehydration with water exposed to low-temperature, low-pressure glow plasma (PTW) in the atmosphere of air (PTWAir) and nitrogen (PTWN) in the course of the fermentation process, the formation of volatile compounds and other quality parameters of the finished beer. The obtained results show that the lager yeast strain initiated the process of fermentation faster after rehydration in the presence of PTWAir compared to all of the other treatments. It was observed that PTWAir significantly changed the composition of volatile compounds in the finished beer, especially by increasing the number of terpenes, which are compounds that positively shape the aroma of beer. In the case of PTWN samples, lower alcohol content, real extract, apparent extract and amount of biomass were observed in all analyzed strains.

Analytical characterization of erucamide degradants by mass spectrometry

Polyolefins use erucamide as one of their primary slip agents. The degradation of erucamide can occur during polymer processing and long-term storage, leading to the formation of numerous oxidation products. Erucamide degradation produces compounds that adversely affect the odor and color properties of polyolefins. The article describes the comprehensive characterization of erucamide degradation products formed in three different lots of low-density polyethylene (LDPE) using thermal desorption-gas chromatography mass spectrometry (TD-GC/MS) and liquid chromatography-high resolution mass spectrometry (LCHRMS) techniques. More than 20 volatile and non-volatile degradation compounds of erucamide were identified in LDPE. The structures of non-volatile degradants were predicted using both the molecular formula generated and MS/MS fragmentation data obtained by LCHRMS. The non-volatile and volatile degradation compounds formed in odorous LDPE resins were compared with that of the reference sample of LDPE having no odor. Further, the plausible mechanism of formation of volatile and non-volatile degradation compounds of erucamide is proposed.

Dynamic Changes in Volatile Compounds of Shaken Black Tea during Its Manufacture by GC × GC-TOFMS and Multivariate Data Analysis.

Changes in key odorants of shaken black tea (SBT) during its manufacture were determined using headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC–TOFMS) and multivariate data analysis. A total of 241 volatiles was identified, comprising 49 aldehydes, 40 esters, 29 alcohols, 34 ketones, 30 aromatics, 24 alkenes, 17 alkanes, 13 furans, and 5 other compounds. A total of 27 volatiles had average relative odor activity values (rOAVs) greater than 1, among which (E)-β-ionone, (E,Z)-2,6-nonadienal, and 1-octen-3-one exhibited the highest values. According to the criteria of variable importance in projection (VIP) > 1, p < 0.05, and |log2FC| > 1, 61 discriminatory volatile compounds were screened out, of which 26 substances were shared in the shaking stage (FL vs. S1, S1 vs. S2, S2 vs. S3). The results of the orthogonal partial least squares discriminate analysis (OPLS-DA) differentiated the influence of shaking, fermentation, and drying processes on the formation of volatile compounds in SBT. In particular, (Z)-3-hexenol, (Z)-hexanoic acid, 3-hexenyl ester, (E)-β-farnesene, and indole mainly formed in the shaking stage, which promoted the formation of the floral and fruity flavor of black tea. This study enriches the basic theory of black tea flavor quality and provide the theoretical basis for the further development of aroma quality control.

Economic analysis of volatile characteristics of Haematococcus pluvialis and the effect of roasting temperature on the profile of volatiles and chemical components

Haematococcus pluvialis, an excellent natural source of astaxanthin, is also enriched with protein, PUFA, carbohydrates. However, the off-flavour of H. pluvialis powder has limited its direct application in food products. The characteristic odour diversity of algae depends on the composition and relative concentration of volatile organic compounds (VOCs). The present study sought to characterize the chemical profile of VOCs of H. pluvialis powders to improve its odour and promote its direct application in functional food and feed products. Additionally, the roasting treatment was applied to improve the flavour, and the effect of roasting temperature on VOCs, nutritional components, and antioxidant activity was investigated. A total of 401 VOCs were identified, with esters being the major class of VOCs, accounting for 63.108% of the total volatiles. Esters, ketone, and aldehydes were the major VOCs contributing to the odour of H. pluvialis powders. After roasting for 30 min at different temperatures, most volatiles were increased, except for esters. Several important flavour VOCs, such as β-ionone, geranylacetone, β-cyclocitral, and nonanal derived from carotenoids and fatty acids, were increased with the increase of the roasting temperatures, exhibiting pleasant odours, such as violet-like, fruity, and fresh odours. The biochemical components, pigments, and antioxidant activity were destroyed with varying degrees during roasting. Additionally, the thermal treatment process accelerated the degradation and oxidation of pigment, proteins, and lipids. Furthermore, the Maillard reaction significantly reduced proteins and carbohydrates. The degradation of pigments and fatty acids resulted in the formation of volatile compounds. Finally, 100–120 °C was considered as an appropriate roasting temperature to improve the flavour of H. pluvialis without interfering with the nutrients.

Key volatile compound formation of rapeseed oil induced via the Maillard reaction during seed roasting

This study was designed to investigate the influence of roasting (150 °C for 0–60 min) on key volatile compounds, sensory evaluation, free amino acids, sugars, and Maillard reaction products (MRPs) of five rapeseed varieties and their oils. During the roasting process, key volatile MRPs of fragrant rapeseed oils (FROs) that increased obviously in concentration were mainly pyrazines. After 60 min of roasting, the stronger nutty-like odor in oil from QH was possibly caused by the high levels of 2,5-dimethylpyrazine (21.72 mg/kg) and 3-ethyl-2,5-dimethylpyrazine (5.06 mg/kg). The 5-hydroxymethylfurfural contents and browning indices increased significantly, whereas reducing sugar and free amino acid contents decreased significantly (p < 0.05). This suggested the extent of the Maillard reaction increased with roasting time. Furthermore, the results of Maillard reaction model system demonstrated glycine, lysine, and histidine could react with glucose to generate 2,5-dimethylpyrazine. Hence, 2,5-dimethylpyrazine is identified as one of the important aroma-active MRPs for FRO.

Effect of industrial processing on the volatiles, enzymes and lipids of wholegrain and rolled oats

The aim of this research was to study the effect of industrial processing stages (kilning, cutting, steaming, rolling and packaging) on the enzymes (lipase and peroxidase), lipids and volatiles of wholegrain and rolled oats. Chemometric data analysis was used to assess the evolution of flavor-related compounds, investigate the relationships between the attributes and select discriminant marker compounds. Oat groats (dehulled oat grain) had significantly (p < 0.05) higher lipase and peroxidase activities, and possessed higher amounts of short-chain volatile fatty acids than the processed oats. The combined effect of kilning and subsequent steaming significantly (p < 0.05) reduced the activity of these enzymes. The use of high temperatures during kilning and steaming triggered the Maillard reaction and Strecker degradation reactions, leading to the formation of odor-active volatile compounds, such as pyrazines, furans and Strecker aldehydes. These compounds are commonly associated with the desirable nutty and toasted aroma of oat-based products. Overall, this study successfully identified key volatile markers and their associated reaction pathways, which can be used to control and optimize the industrial oat processing steps.

Production of Volatile Compounds by a Variety of Fungi in Artificially Inoculated and Naturally Infected Aquilaria malaccensis

Aquilaria malaccensis, the resinous agarwood, is highly valued in the perfumery and medicinal industry. The formation of fragrant agarwood resin inconsistently by various fungi is still not clearly understood. The current study investigatedthe agarwood quality and fungal diversity in artificially inoculated and naturally infected A. malaccensis. The chemical analysis of volatile compounds of agarwood was performed using the Solid Phase Micro Extraction (SPME) method, and the identification of fungi was made through a morphological observation using a light microscope. Gas chromatography analysis revealed the presence of essential compounds related to high-quality agarwood, such as 4-phenyl-2-butanone, β-selinene, α-bulnesene, and agarospirol in both artificially inoculated and naturally infected agarwood but with some differences in the abundance. Further studies onthe fungi associated with agarwood volatile compounds formation showed a total of ten fungal group isolates, which were identified based on morphological and molecular studies. The study revealed that agarwood from both artificial and natural sources were naturally infected with Fusarium, Botryosphaeria, Aspergillus, Schizophyllum, Phanerochaete, Lasiodiplodia, Polyporales, and Ceriporia species. This study has offered a potential opportunity to research further the promising development of fungal strains for artificial inducement of high-quality agarwood formation from A. malaccensis trees.

Effect of proteases on water-soluble and fat-soluble aroma precursors of goat visceras protein hydrolysate

This study investigated the action of proteolytic enzymes in the production of goat viscera hydrolysates, and their flavoring potential. The study focus the production of flavor precursor molecules and the formation of volatile compounds resulting from four hydrolysis treatments: HA - Alcalase®, HF - Flavourzyme®, HN - Neutrase®, and HFN - Flavourzyme® and Neutrase®. The highest degree of hydrolysis (26.74%), number (23 volatiles) and concentration of volatile compounds (274.0 μg/L) were obtained with the action of Alcalase. The main classes of volatile compounds identified in hydrolysates included acids, aldehydes, pyrazines, terpenes and Streacker aldehydes. Amino acids, sugars and fatty acids were identified with higher concentrations in HF and HFN hydrolysates due to the low participation of these precursors in the formation of volatile compounds. Therefore, the use of Alcalase in the proteolysis of goat viscera stood out compared to other enzymes, providing impacting aroma compounds, such as pyrazines, for meat flavor.