Flavor Chemistry Research Articles

Ensuring sustainability in sensory sciences

Ensuring sustainability in sensory sciences

Identification of Key Aromatic Compounds in Basil (Ocimum L.) Using Sensory Evaluation, Metabolomics and Volatilomics Analysis.

Basil (Ocimum L.) is widely used as a flavor ingredient, however research on basil flavor is limited. In the current study, nine basil species were selected, including Ocimum basilicum L.var. pilosum (Willd.) Benth., Ocimum sanctum, Ocimum basilicum cinnamon, Ocimum gratissimum var. suave, Ocimum tashiroi, Ocimum basilicum, Ocimum americanum, Ocimum basilicum ct linalool, and Ocimum basilicum var. basilicum, and their fragrance and flavor characteristics were assessed by sensory evaluation. The results indicated that Ocimum basilicum var. basilicum and Ocimum gratissimum var. suave have a strong clove smell and exhibited a piquant taste. Metabolomics and volatilomics analyses measured 100 nonvolatile metabolites and 134 volatiles. Differential analysis showed that eugenol, γ-terpinene, germacrene D and malic acid were among the most varied metabolites in basil species. Combined with sensory evaluation results, correlation analysis revealed that β-pinene and γ-cadinene contributed to the piquant smell, while eugenol and germacrene D contributed to the clove smell, and malic acid and L-(−)-arabitol contributed to the sweet flavor in basil. This study provided comprehensive flavor chemistry profiles of basil species and could be used as a guide for basil flavor improvement. The better understanding of objective sensory attributes and chemical composition of fresh basil could introduce the improved cultivars with preponderant traits, which is also in accordance with the various demands of breeders and growers, food producers, and consumers.

Impact of species, growing location and cultivar on flavor chemistry of blueberry fruit

Impact of species, growing location and cultivar on flavor chemistry of blueberry fruit

An efficient methodology for modeling to predict wine aroma expression based on quantitative data of volatile compounds: A case study of oak barrel-aged red wines

Correlating aroma expression with volatile compounds has long been an ambition in researches of flavor chemistry. To propose a reliable methodology to depict wine aroma, 76 oak barrel-aged dry red wines were investigated through the combination of machine learning algorithm and multivariate analysis. Aromatic characteristic was evaluated by quantitative descriptive analysis (QDA), while non– or oak derived volatiles were detected by HS-SPME-GC–MS and targeted SPE-GC-QqQ-MS/MS, respectively. Results showed that variable importance for projection values (VIPs) from partial least-squares regression (PLSR) and mean decrease accuracy (MDA) from random forest were efficient parameters for feature selection. The correlating accuracy of the optimal PLSR model to predict intensities of different aroma characteristics through selected volatile compounds could achieve 0.754 to 0.943, representing potential application to manage wine aroma by chemical assay in winemaking. From the perspective of mathematical modeling in the real wine matrix, the network analysis between aroma characteristics and key volatile compounds indicated that the expression of oak aroma was not only directly contributed by volatiles derived from oak wood, but also influenced by ethyl esters, including ethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl decanoate, and ethyl nonanoate.

Flavour chemistry of dehydrated exotic fruits

Dehydrated fruit pieces and purées are commonly used in many food formulations and toppings for food products like yogurts, ice creams, and cereals. However, one of the biggest problems in fruit dehydration is the prevention of the development of unpleasant off-flavour that can negatively impact on the sensory quality of the final dried fruit products. In recent years, fruit dehydration has been conducted using either thermal or non-thermal drying techniques. Therefore, the present review examines how the different dehydration technologies, namely conventional hot air-drying, ultrasonic-assisted hot air-drying, sun-drying, spray-drying, Refractance WindowTM drying, cast-tape drying, thin-layer catalytic far-infrared radiation drying, withering, freeze-drying, microwave-drying, and osmotic dehydration impact on the volatile constituents of the final dried fruit products. Drying processes result in noticeable losses/reduction of several impact odorants. Moreover, some compounds are produced either via: (1) hydrolysis of relevant glycosides under high temperatures, or (2) thermal degradation of volatile and non-volatile precursors as well as oxidation and Maillard reactions which result in the production of heterocyclics, and saturated and unsaturated aldehydes. Of significance is the Refractance WindowTM drying which exhibits high retention potential (~ 90%) of volatile compounds present in fresh fruits. Refractance WindowTM drying technology ensures rapid drying of food products at very low temperature.

Controlled atmosphere storage impacts fruit quality and flavor chemistry of five cultivars of highbush blueberry (Vaccinium corymbosum)

Changes in highbush blueberry fruit quality and flavor chemistry following air or controlled atmosphere storage was determined for five blueberry cultivars. ‘Duke’, Aurora’, ‘Brigitta’, ‘Jersey’ and ‘Liberty’ fruit were stored for six weeks at 1 °C in chambers containing air or 0, 10.0, 12.5, 15.0, 17.5, or 20.0 kPa CO2 with 10.0 kPa O2. Elevated concentrations of CO2 reduced decay but did not affect fruit splitting, which differed among cultivars. Fruit firmness increased 36% in air-stored fruit, but decreased as CO2 concentration increased being 110% and 83% of initial values in fruit stored in 10 and 20 kPA CO2, respectively. Flesh discoloration increased following storage and in response to CO2 concentration. Sugar and acid content tended to increase in fruit stored in elevated CO2 concentrations but sugar/acid ratio declined. Volatile compounds were monitored using headspace solid phase microextraction-2 dimension gas chromatography-time of flight-mass spectroscopy. Concentrations of aldehydes did not change following storage regardless of atmosphere. Monoterpenoids and ketones declined after storage, but were not effected by storage atmosphere. Alcohols and esters increased after storage and in response to CO2 concentration. Ethanol, acetaldehyde and ethyl acetate increased in response to elevated concentrations of CO2 and were 1,100-, 90- and 150-fold greater in fruit stored in 20 kPa CO2 than in fruit prior to storage. Other ethyl and acetate esters also increased in response to elevated CO2 atmospheres. Differences in CO2 tolerance were observed among cultivars with ‘Liberty’ showing the least expression of fermentation-induced volatiles and ‘Aurora’ the least flesh discoloration. While storage of blueberries in elevated concentrations of CO2 is effective to reduce decay, its effects on fruit flavor must be considered in optimizing storage atmospheres.

Comparison of Volatile Compounds Contributing to Flavor of Wild Lowbush (Vaccinium augustifolium) and Cultivated Highbush (Vaccinium corymbosum) Blueberry Fruit Using Gas Chromatography-Olfactometry.

The flavor of blueberry fruit products is an important parameter determining consumer satisfaction. Wild lowbush blueberries are primarily processed into products, but their flavor chemistry has not been characterized. The objective of this study was to characterize the aroma chemistry of lowbush blueberries and compare it with that of highbush. Aroma volatiles of lowbush blueberries from four Canadian provinces and five highbush blueberry cultivars were isolated using headspace solid-phase microextraction (SPME) and characterized using gas chromatography-olfactometry (GC-O) and 2-dimensional gas chromatography-time of flight-mass spectrometry (GC×GC-TOF-MS). Lowbush fruit volatiles were composed of 48% esters, 29% aldehydes and 4% monterpenoids compared to 48% aldehydes, 26% monoterpenoids and 3% esters in highbush fruit. Twenty-three aroma-active peaks were identified in lowbush compared to forty-two in highbush fruit using GC-O. The most aroma-active compounds in lowbush fruit were ethyl 2-methylbutanoate, methyl 2-methylbutanoate, methyl 3-methylbutanoate, ethyl 3-methylbutanoate and ethyl propanoate compared to geraniol, (Z)-3-hexen-1-ol, 1-octen-3-one, α-terpineol and linalool in highbush fruit. The aroma volatile composition was more consistent among lowbush fruit samples than the five highbush cultivars. Aroma-active GC-O peaks were described more frequently as “floral”, “fruity”, “sweet” and “blueberry” in lowbush than in highbush fruit. Results suggest wild lowbush blueberries would provide “fruitier” and “sweeter” flavors to food products than cultivated highbush fruit.

A multi-omics framework reveals strawberry flavor genes and their regulatory elements.

Flavor is essential to consumer preference of foods and is an increasing focus of plant breeding programs. In fruit crops, identifying genes underlying volatile organic compounds has great promise to accelerate flavor improvement, but polyploidy and heterozygosity in many species have slowed progress. Here we use octoploid cultivated strawberry to demonstrate how genomic heterozygosity, transcriptomic intricacy and fruit metabolomic diversity can be treated as strengths and leveraged to uncover fruit flavor genes and their regulatory elements. Multi-omics datasets were generated including an expression quantitative trait loci map with 196 diverse breeding lines, haplotype-phased genomes of a highly-flavored breeding selection, a genome-wide structural variant map using five haplotypes, and volatile genome-wide association study (GWAS) with > 300 individuals. Overlaying regulatory elements, structural variants and GWAS-linked allele-specific expression of numerous genes to variation in volatile compounds important to flavor. In one example, the functional role of anthranilate synthase alpha subunit 1 in methyl anthranilate biosynthesis was supported via fruit transient gene expression assays. These results demonstrate a framework for flavor gene discovery in fruit crops and a pathway to molecular breeding of cultivars with complex and desirable flavor.

Comparative study of volatile composition of major Northern Highbush blueberry (Vaccinium corymbosum) varieties

Blueberries originated from North America and the predominant cultivated species are Vaccinium corymbosum (Northern and Southern Highbush), Vaccinium ashei (Southern Rabbiteye), and Vaccinium angustifolium (Lowbush). Consumer’s demand for high-quality blueberry fruits has driven the interest to better understand the flavor chemistry of blueberry. Forty-five previously identified aroma contributing compounds were further investigated in 11 blueberry varieties, including some developing types. Based on odor activity value, branch-chain esters, terpenes, and aldehydes could be the primary aroma contributors to all 11 blueberry varieties. A heatmap with hierarchical clustering dendrogram showed that the three varieties ORUS 235-4, ORUS 235-3, and ORUS-10-1 were close together with a high level of branch-chain esters and, in turn, close to ‘Draper’ and ‘Duke’. However, they differed from the other varieties, including ‘Aurora’, ‘Bluecrop’, ‘Elliott’, ‘Legacy’, ‘Liberty,’ and ORUS-202-2. One-way ANOVA analysis demonstrated that terpenoids varied the most among varieties. Also, the Pearson correlation showed terpenoids, except eucalyptol, exhibited a strong positive correlation, especially between linalool and α-terpineol. Enantiomer analysis revealed S-(+)-linalool was dominant in all blueberries, whereas the S-(−)-α-terpineol was slightly higher than R-(+)-α-terpineol. This study provided a detailed volatile composition database for unraveling the complex genetics of the various blueberry flavor aspects to assist the breeding purposes of new blueberry crops.

Aroma Perception of Rose Oxide, Linalool and α-Terpineol Combinations in Gewürztraminer Wine

Cis-Rose oxide was found to be an important chiral compound in Gewürztraminer wine, with an enantiomeric ratio range from 76 to 58%. The enantiomeric ratio showed an important influence on white wine aroma when other monoterpenes were present. The aim of this study was to evaluate rose oxide at different ratios and changes to aroma perception, and the interaction of rose oxide with linalool and α-terpineol. A wine model was made based on Gewürztraminer wine. Twelve models were created with different ratios of rose oxide and concentrations of linalool and α-terpineol. Triangle tests, check-all-that-apply (CATA) and descriptive analysis were used to evaluate the aroma of the wines. Results show that the rose oxide ratios of 70:30 and 65:35 were statistically different. Additional descriptive analysis showed that the ratios altered aroma when linalool and α-terpineol were at low and medium concentrations. At high concentrations, linalool and α-terpineol masked any influence from rose oxide. Understanding how monoterpenes alter aroma perception of white wine when at different combinations and concentrations is important to achieving desired wine qualities and helps provide information on how flavor chemistry results can be interpreted without having to run sensory analysis.

The Bacterial Microbiome of the Tomato Fruit Is Highly Dependent on the Cultivation Approach and Correlates With Flavor Chemistry.

The modes of interactions between plants and plant-associated microbiota are manifold, and secondary metabolites often play a central role in plant-microbe interactions. Abiotic and biotic (including both plant pathogens and endophytes) stress can affect the composition and concentration of secondary plant metabolites, and thus have an influence on chemical compounds that make up for the taste and aroma of fruit. While the role of microbiota in growth and health of plants is widely acknowledged, relatively little is known about the possible effect of microorganisms on the quality of fruit of plants they are colonizing. In this work, tomato (Solanum lycopersicum L.) plants of five different cultivars were grown in soil and in hydroponics to investigate the impact of the cultivation method on the flavor of fruit, and to assess whether variations in their chemical composition are attributable to shifts in bacterial microbiota. Ripe fruit were harvested and used for bacterial community analysis and for the analysis of tomato volatiles, sugars and acids, all contributing to flavor. Fruit grown in soil showed significantly higher sugar content, whereas tomatoes from plants under hydroponic conditions had significantly higher levels of organic acids. In contrast, aroma profiles of fruit were shaped by the tomato cultivars, rather than the cultivation method. In terms of bacterial communities, the cultivation method significantly defined the community composition in all cultivars, with the bacterial communities in hydroponic tomatoes being more variable that those in tomatoes grown in soil. Bacterial indicator species in soil-grown tomatoes correlated with higher concentrations of volatiles described to be perceived as “green” or “pungent.” A soil-grown specific reproducibly occurring ASV (amplicon sequence variants) classified as Bacillus detected solely in “Solarino” tomatoes, which were the sweetest among all cultivars, correlated with the amount of aroma-relevant volatiles as well as of fructose and glucose in the fruit. In contrast, indicator bacterial species in hydroponic-derived tomatoes correlated with aroma compounds with “sweet” and “floral” notes and showed negative correlations with glucose concentrations in fruit. Overall, our results point toward a microbiota-related accumulation of flavor and aroma compounds in tomato fruit, which is strongly dependent on the cultivation substrate and approach.

Evaluation of the effect of marination in different seasoning recipes on the flavor profile of roasted beef meat via chemical and sensory analysis.

Marinating is a Chinese meat-processing technique that involves treating meat products in an aged brine containing traditional Chinese spices and other condiments. In this study, beef meats were marinated in different seasoning recipes, including marinade solution of water as control (BS1), marinade solution consisting of water and 2% salt (BS2), marinade solution consisting of water, 2% salt, and 0.5% sugar (BS3), and marinade solution consisting of water, 2% salt, 0.5% sugar, 0.5% soy sauce, and spices (BS4). The effects of different marinade solutions through the tumbling on the flavor profile of roasted beef meat were comprehensively analyzed via chemical and sensory analysis. A total of 82 volatile flavor compounds were identified. Among them, 36 compounds were identified in BS1, 40 compounds in BS2, 46 compounds in BS3, and 64 compounds in BS4. Besides, 4 compounds showed high odor activity values (OAVs) in marinated samples, including decanal, trans-2-decenal, linalool, and nonanal. The metal oxide sensors of E-nose distinguished the differences among the different marinated samples. Marinated beef samples BS2 and BS3 showed a significant increase in the values of thiobarbituric acid reactive substances (TBARS). In contrast, marinated beef sample BS4 significantly reduced TBARS value to 4.11µg MDA/kg beef. It can be concluded that using this different seasoning processing enhances the aroma profile and provides a reference for the production of marinated meat products. PRACTICAL APPLICATIONS: Marinating is a Chinese meat-processing technique that involves treating meat products in an aged brine containing traditional Chinese spices and other condiments. Processing beef meat with different marinade solutions could enhance its aroma profile. Therefore, this study aimed to evaluate the effect of marination in different marinade solutions through the tumbling on the volatile flavor compounds of roasted beef meat using HS-SPME-GC-MS and E-nose. The obtained results from this study could enrich the theoretical knowledge of the flavor chemistry of marinated beef meat and provide a reference for the production of marinated meat products.

Preface

The 2021 2nd International Conference on Agricultural Science and Technology and Food Engineering (ASTFE 2021) was successfully held in Qingdao, China on May 28-30,2021. ASTFE 2021 is to bring together innovative academics and industrial experts in the field of agricultural science and technology and food engineering to a common forum. The primary goal of the conference is to promote research and developmental activities in agricultural science and technology and food engineering and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world.The conference model was divided into two sessions, including oral presentations and keynote speeches. In the first part, some scholars, whose submissions were selected as the excellent papers, were given 15 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches.In this conference, we were greatly honored to have three distinguished experts to serve as our Conference Chairman. There were over 60 experts and scholars in the area of agricultural science and technology and food engineering representing different famous universities and institutes around the globe to form our organizing committee and technology program committee. During the conference, we were pleased to invite two distinguished experts to present their insightful speeches. Prof. Wang Fei, from Agriculture Products Processing Research Institute, Chinese Academy of Tropical Agricultural Sciences. His research area: Agricultural products processing; Utilization of natural cellulose in functional materials; Recycle and utilization of carbon dioxide; Surface modification of porous ceramic membrane. Another keynote speaker, A. Prof. Zhu Wenhui, from College of Food Science and Engineering, Bohai University. She has outstanding research in Processing and storage of aquatic products, Flavor chemistry of aquatic products. Their insightful speeches had triggered heated discussion. Every participant praised this conference for disseminating useful and insightful knowledge.The participants of the conference were from most part of the world, with background of either academia or industry, even well-known enterprise. The success and prosperity of the conference is reflected high level of the papers received. The proceedings are a compilation of the accepted papers and represent an interesting outcome of the conference. This book covers 2 chapters: 1. Agricultural science and technology; 2. Food Engineering.We would like to acknowledge all of those who supported ASTFE 2021. Each individual and institutional help were very important for the success of this conference. Especially we would like to thank the organizing committee for their valuable advices in the organization and helpful peer review of the papers. We sincerely hope that ASTFE 2021 will be a forum for excellent discussions that will put forward new ideas and promote collaborative researches. We are sure that the proceedings will serve as an important research source of references and the knowledge, which will lead to not only scientific and engineering progress but also other new products and processes.List of Committee member are available in this pdf.

Quality Attributes of Ultra-High Temperature-Treated Model Beverages Prepared with Faba Bean Protein Concentrates.

The objective of this research was to develop a model faba bean drink with a high concentration of protein (>4% w/w). The protein molecular weights and frequency for both faba and soy were assessed using SDS-PAGE. Results showed similarities in the protein molecular weight of both faba and soy (mainly 11S globulin ~Glycinin and 7S globulin ~β-conglycinin). Thus, faba can be considered as a potential soy replica in plant-based milk beverages. Oil-in-water emulsions (5–8% w/w available protein) were prepared using faba bean protein concentrate (FPC), 1% sunflower oil, and 0.2% sunflower lecithin. These emulsions were used as model beverages and were further investigated for UHT processibility, stability, and physicochemical properties. The physicochemical properties of emulsions at various processing stages viz., coarse emulsification, homogenisation, and UHT, were measured. An increase in the protein concentration and thermal treatment resulted in an increased oil droplet size, coalescence and flocculation, and protein aggregation. Lower protein concentrations viz., 5–6%, showed greater negative ζ-potential, and thereby, high dispersibility through enhanced electrostatic repulsions than those of higher concentrations (7–8%). Furthermore, an increase in protein concentration and UHT treatment resulted in an increased creaming index. In total, 21 different volatile compounds were detected and quantified, representing different chemical classes, namely alcohols, aldehydes, ketones, esters, furan, and acids. These volatiles have major consequences for the overall flavour chemistry of the model beverage product. Overall, this study showed the potential for application of faba bean as a protein source in UHT-treated legume-based beverages and identified areas for further development.

The Flavor Chemistry of Fortified Wines-A Comprehensive Approach.

For centuries, wine has had a fundamental role in the culture and habits of different civilizations. Amongst numerous wine types that involve specific winemaking processes, fortified wines possess an added value and are greatly honored worldwide. This review comprises the description of the most important characteristics of the main worldwide fortified wines—Madeira, Port, Sherry, Muscat, and Vermouth—structured in three parts. The first part briefly describes the chemistry of wine flavor, the origin of typical aroma (primary, secondary and tertiary), and the influencing parameters during the winemaking process. The second part describes some specificities of worldwide fortified wine, highlighting the volatile composition with particular emphasis on aroma compounds. The third part reports the volatile composition of the most important fortified wines, including the principal characteristics, vinification process, the evolution of volatile organic compounds (VOCs) during the aging processes, and the most important odor descriptors. Given the worldwide popularity and the economic relevance of fortified wines, much research should be done to better understand accurately the reactions and mechanisms that occur in different stages of winemaking, mainly during the oxidative and thermal aging.

Free and Glycosidic Volatiles in Tamarillo (Solanum betaceum Cav. syn. Cyphomandra betacea Sendt.) Juices Prepared from Three Cultivars Grown in New Zealand.

This study investigated the free and glycosidic-bound volatiles in the juice samples of three tamarillo cultivars (i.e. Amber, Mulligan, and Laird's Large) that are widely grown in New Zealand. Juice samples were prepared from fruits at different ripening stages (green, middle, and ripe). Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry was applied to analyze the free volatiles in the samples. A total of 20 free volatiles were detected. Among the samples, the ripe Mulligan juice gave the highest contents of free terpenoids (424 μg/L) and esters (691 μg/L). The glycosidic-bound volatiles were prepared by solid-phase extraction. The matrix effect was evaluated based on the recovery rate of analytes containing multiple aglycone classes. From the results, phenyl β-d-glucopyranoside was selected to compensate the matrix effect caused by insufficient acquisition of glycosidic volatiles during analyte preparation. In all the ripe-fruit juice samples, the aglycones 4-hydroxy-2,5-dimethyl-3(2H)-furanone and trans-2, cis-6-nonadienal were found to give high odor activity values. According to multivariate statistical analysis, 11 free volatiles and 22 glycosidic volatiles could be potentially applied as volatile makers to distinguish the juice samples. This study has provided a comprehensive understanding of the flavor chemistry of tamarillo juices, with a focus on the potential role of glycosidic aglycones as aroma contributors to tamarillo products.

Roasting process shaping the chemical profile of roasted green tea and the association with aroma features

Roasting process impacts the chemical profile and aroma of roasted tea. To compare the impacts of far-infrared irradiation and drum roasting treatments (light, medium and heavy degrees), the corresponding roasted teas were prepared from steamed green tea for chemical analyses and quantitative descriptive analysis on aroma, and correlations between volatiles and aroma attributes were studied. There were 8 catechins, 13 flavonol glycosides and 105 volatiles quantified. Under heavy roasting treatments, most catechins and flavonol glycosides decreased, and aldehydes, ketones, furans, pyrroles/pyrazines, and miscellaneous greatly increased, while far-infrared irradiated teas had distinct nutty aroma compared with the roasty and burnt odor of drum roasted teas. The weighted correlation network analysis result showed that 56 volatiles were closely correlated with the aroma attributes of roasted teas. This study reveals the differential chemical and sensory changes of roasted teas caused by different roasting processes, and provides a novel way for flavor chemistry study.

The flavor chemistry of pork broth: a review

Pork is widely consumed in the world. The unique and attractive flavor is one of the major drivers of consumer liking for pork. Even though the flavor of pork products varies heavily depending on the processing and cooking method, pork broth is very popular in East Asian countries and could serve as a perfect model for studying the flavor chemistry of pork. While quite a number of studies have been carried out on this topic, only a few meet the basic criteria of modern flavor chemistry approaches. By reviewing these publications, 12 volatile compounds, including 4 sulfur containing compounds, 4 aldehydes, 1 alcohol, 1 ester, 1 lactone, and 1 carboxylic acid, were selected as the major aroma active components in pork broth. While the taste of pork broth mainly comes from the basic tastants such as amino acids, organic acids, inorganic minerals, and nucleotides, the role of taste modifiers in pork broth has yet to be investigated. More research is needed to further clarify the flavor chemistry of pork broth.

361 Beef flavor chemistry and how it influences sensory perception

Abstract Flavor can be simply defined as the combination of taste and aroma. Taste refers to the five basic receptors: sweet, salty, sour, bitter, and umami. Flavor is the perception of chemical compounds reacting with receptors in the oral and nasal cavities (aroma) in combination with taste. For beef, flavor is considered a primary eating quality trait. Flavor is developed during cooking through a combination of numerous chemical reactions, principally the Maillard reaction and oxidation of lipids. Any factor which mediates precursor compounds to these reactions may influence flavor chemistry and final perceived flavor. For the Maillard reaction, water-soluble compounds, such as free-amino acids and sugars, are essential and allow for the development of characteristic beef flavors. Likewise, oxidation of lipids, to a degree, provides beef -species-specific flavor. However, too much oxidation contributes to off-flavor. Both pre- and post-harvest factors may influence beef flavor precursor content and composition prior to cooking. Beef finishing diet is well understood to influence fatty acid composition. Meanwhile, carcass grade and muscle type each influence fatty acids. During post-mortem aging, free-amino acids and other metabolites accumulate in response to proteolysis. Recent work indicates that packaging type and retail environment also influence flavor precursor compounds. Finally, the aforementioned flavor pathways, lipid oxidation and the Maillard reaction, are initiated and accelerated during cooking. Therefore, degree-of-doneness and cookery type greatly influence beef flavor chemistry. These examples briefly depict how beef flavor chemistry may be influenced by common production factors, retail settings, and consumer preparation of beef. The resulting beef flavor dictates consumer liking of beef. Therefore, understanding beef flavor chemistry is integral to maintaining or increasing consumer satisfaction with beef.

Nonvolatile taste compounds of Shanghai smoked fish: A novel three stages control techniques.

In this work, the effect of processing stages including first soaking (FS), frying after first soaking (FFS), and second soaking (SS) on nonvolatile taste compounds of Shanghai smoked fish was investigated using high‐performance liquid chromatography (HPLC) and automatic amino acid analyzer. Results showed that the contents of free amino acids (FAAs) ranged from 396.94 to 585.79 mg/100 g and 5′‐inosine monophosphate (IMP, as main umami nucleotide) from 215.91 to 284.56 mg/100 g in Shanghai smoked fish, respectively. Moreover, the contents of Glu and Gly as main umami amino acids ranged from 1.64 to 107.32 mg/100 g and 61.61 to 108.88 mg/100 g, respectively. TAV values of IMP, Asp, and Glu in Shanghai smoked fish reached 11.38, 2.73, and 21.46, respectively. The obvious difference could be observed using principal component analysis (PCA) in three processing stages of Shanghai smoked fish. Therefore, probing into the nonvolatile flavor of Shanghai smoked fish could not only enrich the theoretical basis of flavor chemistry in freshwater fish fields, but probe into the formation mechanisms of taste compounds in further study.