Sprouting improves the flavour quality of faba bean flours

The influence mechanism of phospholipids structure and composition changes caused by oxidation on the formation of flavor substances in sturgeon caviar

The oxidation-induced phospholipids (PLs) underwent structural and compositional analysis, alongside the establishment of a simulation system to verify the link between phospholipid oxidation and flavor substances formation in sturgeon caviar. Structural alterations of PLs were tracked using 31P and 1H nuclear magnetic resonance (NMR), electron spin resonance spectroscopy (ESR), and Raman spectroscopy. The findings revealed a reduction in phosphatidylcholine (PC) and phosphatidylethanolamine (PE) from 82.3% and 10.4% to 58.2% and 5.8% respectively. Free radical signals exhibited an initial increase followed by a decrease. The diminished intensity in Raman spectra at 970 and 1080 cm-1 indicated reduced fat unsaturation attributable to PLs oxidation. Correlation analysis highlighted a significant association between PC and PE containing C22:6, C20:5, C20:4, and C18:2 with flavor substances, suggesting their role as key precursors for flavor development. This study established a theoretical basis for understanding the change of flavor quality in sturgeon caviar during storage.

Minimizing anti-nutritional factors in wet protein extraction from Swedish faba beans through the application of response surface methodology

Faba beans, rich in protein and ideal for Swedish cultivation, are limited in food industry use due to anti-nutritional factors (ANFs) that hinder nutrient absorption. An extraction method was developed in our study to mitigate ANFs in faba beans, using aqueous alkaline methods and isoelectric precipitation with differential salt concentration. This method yielded 15.8 g of protein per 100 g of flour, with a protein concentration exceeding 83% of the total extract. It reduced ANFs like phytic acid (28.0%), lectins (87.5%), vicine (98.5%), and convicine (99.7%). Extraction conditions were optimized using response surface methodology, identifying pH 6, 2 h, and 20 °C as the most effective parameters, achieving an 86% reduction in phytic acid, closely matched the model's predictions (R2 = 0.945). This method effectively reduced ANFs, offering a sustainable approach for producing proteins suitable for diverse food products, including plant-based alternatives.

Short-term germinated legume flours as functional ingredients in food products

Unlocking the potential of legumes through short-term germination offers an innovative approach to improving the functionality of the resultant flour. This review examines the multifaceted benefits of short-term germinated legume flour, emphasizing the enzymatic activities that breakdown complex legume compounds into simpler forms and reduce anti-nutritional factors. This process improves digestibility, nutrient bioavailability, and health-promoting properties. Furthermore, short-term germination enhances the techno-functional properties of legume flours without compromising their quality, avoiding excessive starch and protein degradation associated with prolonged germination. This review also explores the applications of short-term germinated legume flours in developing nutritious and healthy food products tailored to diverse dietary needs. Subsequent integration of these short-term germinated flours into food products provides a route for the development of cost-effective, nutritious, and sustainable options that can address malnutrition and enhance overall well-being.

Effects of Efficient Ethylene Remover on the Lignification of Fresh Faba Bean (Vicia faba L.) during Storage

Postharvest ethylene accumulation and lignification are significant issues affecting the storage quality of fresh faba beans, resulting in rapid quality decline. However, there is still a lack of effective preservation methods to preserve the quality of faba beans during storage. This study aimed to investigate the regulation of lignification in faba beans during storage using a high-efficiency ethylene remover (HEER), examining physiological responses, key enzyme activities, and transcriptomic changes. Results showed that the HEER treatment inhibited the lignification, reducing it by 45% and lowering the respiratory rate of fresh pods by 32.8% during storage. Additionally, the HEER treatment suppressed respiration rates and the activities of lignin synthesis-related enzymes, including phenylalanine ammonia-lyase (from 353.73 to 246.60 U/g), cinnamic acid-4-hydroxylase (from 635.86 to 125.00 U/g), 4-coumarate: coenzyme A ligase (from 1008.57 to 516.52 U/g), and cinnamyl-alcohol dehydrogenase (from 129.42 to 37.12 U/g), thus slowing lignin accumulation. During storage, the hardness of fresh faba bean increased by 9.79% from the initial period, being 1.44 times higher than that of HEER. On days 8 and 16 of storage, the respiratory rate of the treated beans decreased by 24.38% and 4.12%, respectively. Physiological and enzyme activity analyses indicated that HEER treatment-induced increase in hardness was associated with the phenylpropanoid metabolic pathway. Moreover, the HEER significantly down-regulated the expression of several key genes, namely FaPAL, FaC4H, and FaCAD. This study helps to deepen the understanding of the inhibition of lignification by HEER and provide new insights for the development of preservation technology of faba bean.

Plant-based seafood alternatives: Current insights on the nutrition, protein-flavour interactions, and the processing of these foods

Fish are an important food source; however, the sustainability of current seafood supplies is a major concern for key stakeholders. The development of plant-based seafood alternatives may be suitable products to alleviate some of the pressures on aquatic ecosystems and help support environmental sustainability. However, the wide-spread adoption of these products weighs heavily on the ingredients used in the formulations which should not only satisfy nutritional and sustainability targets but must also meet consumer approval and functionality. In this review, we highlight recent advances in our understanding of the nutritional quality and sensory challenges in particular flavour (which includes taste and aroma), that have so far proven difficult to overcome in the development of plant-based seafood alternatives. Protein interactions that contribute to flavour development in plant-based seafood alternatives and the factors that impact these interactions are also discussed. We also review the recent advances in the innovative technologies used to improve the texture of products in this emerging food category. Finally, we highlight key areas for targeted research to advance the development of this growing segment of food products.

Unraveling the Impacts of Germination on the Volatile and Fatty Acid Profile of Intermediate Wheatgrass (Thinopyrum intermedium) Seeds

Intermediate wheatgrass (IWG) is a promising perennial grain explored for mainstream food applications. This study investigated the effects of different germination temperatures (10, 15, and 20 °C) and durations (2, 4, and 6 days) on IWG's volatile and fatty acid (FA) profiles. A method using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was optimized through response surface design to extract the volatile compounds, achieving ideal extraction conditions at 60 °C for 55 min. Multiple headspace extraction (MHE) was used for volatile compound quantification. Fifty-eight compounds were identified and quantified in IWG flour, mainly alcohols, aldehydes, hydrocarbons, terpenes, esters, organic acids, and ketones. The main FAs found were linoleic acid (C18:2), oleic acid (C18:1), palmitic acid (C16:0), and linolenic acid (C18:3). Principal component analysis showed a direct correlation between volatile oxidation products and FA composition. Germination at 15 °C for 6 days led to a reduced presence of aldehydes and alcohols such as nonanal and 1-pentanol. Therefore, optimized germination was successful in reducing the presence of potential off-odor compounds. This study provides valuable insights into the effects of germination on IWG flour, showing a way for its broader use in food applications.

Reduction of antinutrients and off-flavour in kidney bean flour by acidic and alkaline reactive extrusion

The presence of antinutrients and undesirable flavours in kidney bean flour poses challenges to consumer acceptance. Although extrusion can mitigate antinutrients to some extent, its impact on reducing beany flavour in bean flour remains underexplored. This study investigated the effects of injecting acetic acid or sodium carbonate solutions at three concentration levels (0.05, 0.1, 0.15 mol/L), in conjunction with three temperature profiles (40/60/80/80/90, 40/60/80/90/110, 50/70/90/110/130 °C) and two feed moisture levels (25, 30 %), on the removal of antinutrients (condensed tannins, trypsin inhibitor activity, phytic acid, raffinose family oligosaccharides) and reduction of volatile compounds that contribute to beany flavour in whole kidney bean flour. The results showed that all concentrations of acetic acid and sodium carbonate solutions effectively reduced condensed tannins compared to water, especially at 130 °C extrusion temperature. Introducing acetic acid and sodium carbonate solutions at a concentration of 0.15 mol/L led to 72 and 90 % reduction of total raffinose family oligosaccharide content, respectively, in contrast to the 17 % reduction observed with water alone. The incorporation of sodium carbonate solution reduced the total volatile compounds by 45-58 % as compared with water (23-33 %) and acetic acid (11-27 %). This reduction was primarily due to the reduction of aldehydes, alcohols, and aromatic hydrocarbons. These results indicate that injecting sodium carbonate solution during extrusion can effectively reduce antinutrients and beany flavour compounds in kidney bean flour.

Effect of Germination on the Digestion of Legume Proteins

As one of the main sources of plant protein, it is important to improve the protein digestibility of legumes. Faced with population growth and increasing environmental pressures, it is essential to find a green approach. Germination meets this requirement, and in the process of natural growth, some enzymes are activated to make dynamic changes in the protein itself; at the same time, other substances (especially anti-nutrient factors) can also be degraded by enzymes or their properties (water solubility, etc.), thereby reducing the binding with protein, and finally improving the protein digestibility of beans under the combined influence of these factors The whole process is low-carbon, environmentally friendly and safe. Therefore, this paper summarizes this process to provide a reference for the subsequent development of soybean functional food, especially the germination of soybean functional food.

Effect of different conditions on the germination of coix seed and its characteristics analysis

Coix seed (CS) has high nutritional value, but the deep processing of CS is relatively limited. Sprouting can significantly improve nutritional value, laying the foundation for efficient consumption or further processing. The optimal conditions for the germination of CS are a soaking temperature of 36 °C for 10 h and a germination temperature of 29 °C for 24 h. Under these conditions, the final germination rate of CS reached 90%. Additionally, the content of γ-aminobutyric acid was 21.205 mg/100 g; soluble protein, free amino acids, γ-aminobutyric acid, and other essential substances increased in CS. Especially after germination, the γ-aminobutyric acid (GABA) content increased by 7.8 times compared with the GABA content of ungerminated CS. Therefore, the nutritional value and flavor of germinated CS are better than those of ungerminated ones, which establishs a solid foundation for its application in developing various products such as compound health drinks, coix yogurt, and others.

Application of legumes in plant-based milk alternatives: a review of limitations and solutions

In recent years, a global shift has been observed toward reducing the consumption of animal-derived foods in favor of healthier and more sustainable dietary choices. This has led to a steady growth in the market for plant-based milk alternatives (PBMAs). Projections suggest that this market will reach a value of USD 69.8 billion by 2030. Legumes, being traditional and nutritious ingredients for PMBAs, are rich in proteins, dietary fibers, and other nutrients, with potential health benefits such as anticancer and cardiovascular disease prevention. In this review, the application of 12 legumes in plant-based milk alternatives was thoroughly discussed for the first time. However, compared to milk, processing of legume-based beverages can lead to deficiencies such as nutritional imbalance, off-flavor, and emulsion stratification. Considering the potential and challenges associated with legume-based beverages, this review aims to provide a scientific comparison between legume-based beverages and cow's milk in terms of nutritional quality, organoleptic attributes and stability, and to summarize ways to improve the deficiencies of legume-based beverages in terms of raw materials and processing method improvements. In conclusion, the legume-based beverage industry will be better enhanced and developed by improving the issues.

Flavor, physicochemical properties, and storage stability of P. lobata-coix seed fermented beverage produced by A. aegerita

Pueraria lobata and coix seeds have complementary nutritional profiles, and their nutritional value can be enhanced through biotransformation. Agrocybe aegerita (A. aegerita) is a highly nutritious mushroom with a rich enzyme content. This study investigated the flavor, physicochemical properties, and storage stability of P. lobata-coix seed fermented beverage (PCFB) by A. aegerita. Sixty volatile compounds were detected by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. Compared to unfermented PCFB, fermentation with A. aegerita enhanced its physicochemical properties, with the contents of essential amino acids, γ-Aminobutyric acid, and soluble proteins increasing from 16.81%, 2.64 mg/100 mL, and 49.40% to 21.06%, 4.20 mg/100 mL, and 53.08%, respectively. Two efficient shelf-life prediction models of PCFB were established with the Arrhenius model using pH and sensory evaluation as indexes. These findings demonstrate that PCFB is a novel, high-quality beverage and provide a foundation for potential industrial production of PCFB using A. aegerita.

Oxidative Stability and Pasting Properties of High-Moisture Japonica Brown Rice following Different Storage Temperatures and Its Cooked Brown Rice Flavor

The study proposed to investigate the impacts of storage temperatures (15, 20, 25 °C) on the oxidative stability (peroxide value, carbonyl value, malondialdehyde content) and sensory attributes (pasting properties, cooked brown rice flavor) of high-moisture japonica brown rice. According to the findings, the peroxide value, the carbonyl value, and the malondialdehyde content of high-moisture japonica brown rice stored at a temperature of 15 °C exhibited consistently low levels, and the pasting properties were favorable. In addition, 22 out of 51 flavor volatiles were screened as key differential volatile flavor compounds in cooked brown rice via a combination of ANOVA and orthogonal projections to latent structures-discriminant analysis (OPLS-DA). Among them, 3-heptylacrolein had an aroma of fat and mushroom, and its contents were higher at 15 °C and 20 °C. These findings could serve as a valuable reference for storing high-moisture japonica brown rice under low temperature conditions as well as for investigating the flavor characteristics of cooked brown rice derived from this variety.

Correlation investigation between core microbe inoculation and the evolution of flavor characteristics during the storage of sturgeon caviar (Acipenser gueldenstaedtii)

The volatile and non-volatile compounds were monitored to investigate the microbial evolution associated with the characteristic flavors for sturgeon caviar during refrigeration. The results revealed that the composition of volatile compounds changed significantly with prolonged refrigeration time, especially hexanal, nonanal, phenylacetaldehyde, 3-methyl butyraldehyde, and 1-octen-3-ol. The nonvolatile metabolites were mainly represented by the increase of bitter amino acids (Thr. Ser, Gly, Ala, and Pro) and a decrease in polyunsaturated fatty acids, especially an 18.63 % decrease in 5 months of storage. A total of 332 differential metabolites were mainly involved in the biosynthetic metabolic pathways of α-linolenic acid, linoleic acid, and arachidonic acid. The precursors associated with flavor evolution were mainly phospholipids, including oleic, linoleic, arachidonic, eicosapentaenoic (EPA), and docosahexaenoic (DHA) acids. The most abundant at the genus level was Serratia, followed by Arsenophnus, Rhodococcus, and Pseudomonas, as obtained by high-throughput sequencing. Furthermore, seven core microorganisms were isolated and characterized from refrigerated caviar. Among them, inoculation with Mammalian coccus and Bacillus chrysosporium restored the flavor profile of caviar and enhanced the content of nonvolatile precursors, contributing to the characteristic aroma attributes of sturgeon caviar. The study presents a theoretical basis for the exploitation of technologies for quality stabilization and control of sturgeon caviar during storage.

The effect of different pre-treatments on unformulated pulse-based milk analogs: physicochemical properties and consumer acceptance

This is the first part of a study on developing pulse-based milk analogs using chickpea, faba bean, and cowpea as raw materials. The objectives of the present study were to determine the processing conditions for pulse-based milk analog production at laboratory-scale and to investigate the effects of some pre-treatments such as dry milling (control), soaking and wet milling, blanching, blanching and dehulling, vacuum, and germination on lipoxygenase (LOX) activity of the raw material and some physicochemical and sensory properties of the final products. Dry milling provided the lowest LOX activity and the highest yield while soaking and wet milling resulted in a substantial increase in LOX activity, lower product yield, and a final product with lower whiteness value, regardless of the pulse type. Germination caused a significant decrease in LOX activity in all pulse types, while milk analogs produced from germinated pulses received the lowest acceptability scores from consumers.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05836-7.

Untargeted Lipidomics Reveal Quality Changes in High-Moisture Japonica Brown Rice at Different Storage Temperatures

Low temperatures are an effective way of delaying grain rancidity and deterioration. However, little is known about the difference in quality changes in high-moisture japonica brown rice at different storage temperatures. In this study, the storage quality changes in japonica brown rice with a 15.50% moisture content stored at 15 °C, 20 °C, and 25 °C were investigated. In addition, an untargeted lipidomics analysis coupled with gas chromatography and mass spectrometry (GC-MS) was applied to analyze the volatile compounds and metabolite changes in the high-moisture japonica brown rice. The results showed that storage at 15 °C could well maintain the color and aroma stability of the brown rice and delay the increase in fatty acid value (FAV). The lipidomics results showed that storage at 15 °C delayed glycerolipid and sphingolipid metabolism and reduced glycerophospholipid catabolism in the brown rice. The low-temperature environment regulated these three metabolic pathways to maintain higher contents of triglycerides (TG), phosphatidylserine (PS), abd phosphatidylethanolamine (PE), and lower contents of diglycerides (DG), OAcyl-(gamma-hydroxy) FA (OAHFA), ceramides (Cer), and glycosylceramides (Hex1Cer) in the high-moisture japonica brown rice, which maintained the storage stability of the brown rice. Our results proposed the cryoprotection mechanism of postharvest brown rice from the perspective of volatile compounds and metabolite changes, providing a foothold for the further exploration of low-temperature storage as a safe and efficient cryoprotectant in the grain storage field.

The challenge of breeding for reduced off-flavor in faba bean ingredients

The growing interest in plant protein sources, such as pulses, is driven by the necessity for sustainable food production and climate change mitigation strategies. Faba bean (Vicia faba L.) is a promising protein crop for temperate climates, owing to its remarkable yield potential (up to 8 tonnes ha-1 in favourable growing conditions) and high protein content (~29% dry matter basis). Nevertheless, the adoption of faba bean protein in plant-based products that aim to resemble animal-derived counterparts is hindered by its distinctive taste and aroma, regarded as "off-flavors". In this review, we propose to introduce off-flavor as a trait in breeding programs by identifying molecules involved in sensory perception and defining key breeding targets. We discuss the role of lipid oxidation in producing volatile and non-volatile compounds responsible for the beany aroma and bitter taste, respectively. We further investigate the contribution of saponin, tannin, and other polyphenols to bitterness and astringency. To develop faba bean varieties with diminished off-flavors, we suggest targeting genes to reduce lipid oxidation, such as lipoxygenases (lox) and fatty acid desaturases (fad), and genes involved in phenylpropanoid and saponin biosynthesis, such as zero-tannin (zt), chalcone isomerase (chi), chalcone synthase (chs), β-amyrin (bas1). Additionally, we address potential challenges, including the need for high-throughput phenotyping and possible limitations that could arise during the genetic improvement process. The breeding approach can facilitate the use of faba bean protein in plant-based food such as meat and dairy analogues more extensively, fostering a transition toward more sustainable and climate-resilient diets.

Flavour by design: food-grade lactic acid bacteria improve the volatile aroma spectrum of oat milk, sunflower seed milk, pea milk, and faba milk towards improved flavour and sensory perception

BACKGROUND

The global market of plant-based milk alternatives is continually growing. Flavour and taste have a key impact on consumers' selection of plant-based beverages. Unfortunately, natural plant milks have only limited acceptance. Their typically bean-like and grassy notes are perceived as "off-flavours" by consumers, while preferred fruity, buttery, and cheesy notes are missing. In this regard, fermentation of plant milk by lactic acid bacteria (LAB) appears to be an appealing option to improve aroma and taste.

RESULTS

In this work, we systematically studied LAB fermentation of plant milk. For this purpose, we evaluated 15 food-approved LAB strains to ferment 4 different plant milks: oat milk (representing cereal-based milk), sunflower seed milk (representing seed-based milk), and pea and faba milk (representing legume-based milk). Using GC‒MS analysis, flavour changes during anaerobic fermentations were studied in detail. These revealed species-related and plant milk-related differences and highlighted several well-performing strains delivered a range of beneficial flavour changes. A developed data model estimated the impact of individual flavour compounds using sensory scores and predicted the overall flavour note of fermented and nonfermented samples. Selected sensory perception tests validated the model and allowed us to bridge compositional changes in the flavour profile with consumer response.

CONCLUSION

Specific strain-milk combinations provided quite different flavour notes. This opens further developments towards plant-based products with improved flavour, including cheesy and buttery notes, as well as other innovative products in the future. S. thermophilus emerged as a well-performing strain that delivered preferred buttery notes in all tested plant milks. The GC‒MS-based data model was found to be helpful in predicting sensory perception, and its further refinement and application promise enhanced potential to upgrade fermentation approaches to flavour-by-design strategies.

Faba Bean Flavor Effects from Processing to Consumer Acceptability

Faba beans as an alternative source of protein have received significant attention from consumers and the food industry. Flavor represents a major driving force that hinders the utilization faba beans in various products due to off-flavor. Off-flavors are produced from degradation of amino acids and unsaturated fatty acids during seed development and post-harvest processing stages (storage, dehulling, thermal treatment, and protein extraction). In this review, we discuss the current state of knowledge on the aroma of faba bean ingredients and various aspects, such as cultivar, processing, and product formulation that influence flavour. Germination, fermentation, and pH modulation were identified as promising methods to improve overall flavor and bitter compounds. The probable pathway in controlling off-flavor evolution during processing has also been discussed to provide efficient strategies to limit their impact and to encourage the use of faba bean ingredients in healthy food design.

Exploration of molecular interaction between different plant proteins and 2-pentylfuran: based on multiple spectroscopy and molecular docking

BACKGROUND

Soy protein, peanut protein and wheat protein are commonly applied in plant-based products, but specific off-odor makes it difficult for consumers to accept, with 2-pentylfuran being one of the most representative flavors. In this study, 2-pentylfuran was employed as an example to explore the behavior and mechanism of the three proteins in absorbing off-odors.

RESULTS

Gas chromatographic-mass spectrometric analysis indicated that different plant proteins were able to adsorb 2-pentylfuran. Circular dichroism proved 2-pentylfuran could drive the α-helix to β-sheet transition of soy protein, which was not obvious in peanut protein or wheat protein. Ultraviolet spectroscopy tentatively determined that 2-pentylfuran caused changes in the tyrosine and tryptophan microenvironments of different plant proteins, which were further evidenced by synchronous fluorescence at fixed wavelength intervals of 15 nm and 60 nm. Static quenching of protein intrinsic fluorescence indicated that they formed a stable complex with 2-pentylfuran, except for wheat protein (dynamic quenching).

CONCLUSION

The various conformations of the three proteins are the main reason for the difference in flavor retention of protein. Soy protein, peanut protein and wheat protein adsorbing 2-pentylfuran relies on non-covalent forces, especially hydrophobic interactions, maintained between the protein and 2-pentylfuran. © 2023 Society of Chemical Industry.

Effects of Low-Temperature and Low-Salt Fermentation on the Physicochemical Properties and Volatile Flavor Substances of Chinese Kohlrabi Using Gas Chromatography–Ion Mobility Spectrometry

To explore the effect of low-temperature and low-salt fermentation on the volatile flavor substances of Chinese kohlrabi, low-temperature and low-salt fermented Chinese kohlrabi (LSCK) and traditional high-salt fermented Chinese kohlrabi (HSCK) were produced. The physicochemical and texture properties of the two kinds of Chinese kohlrabies were evaluated. Headspace gas chromatography-ion mobility spectrometry (GC-IMS) and electronic nose (E-nose) were used to analyze the volatile flavor substances of the kohlrabi. The results showed that the total acid content significantly decreased (p < 0.05), while protein and reducing sugar contents significantly increased (p < 0.05) by low-temperature and low-salt fermentation. A total of 114 volatile flavor substances were identified. The alcohol, ketone, pyrazine, ether, and nitrile contents in LSCK were significantly higher than those in HSCK (p < 0.05). Moreover, the unpleasant flavor from the 3-methylbutyric acid formation was effectively depressed in LSCK. The principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) models established by multivariate statistical analysis significantly distinguished the two types of kohlrabies. Multivariate statistical analysis suggested that 16 volatile flavor substances with VIP >1, including tetrahydrothiophene, ethyl 3-(methylthio)propanoate, 3-methylbutyric acid, hexanenitrile, and 3-methyl-3-buten-1-ol, could be used as potential biomarkers for identifying LSCK and HSCK. The E-nose analysis further demonstrated that there was a significant difference in overall flavor between the LSCK and HSCK. The present study provides support for the development of green processing technology and new low-salt Chinese kohlrabi products.

Origins of volatile compounds and identification of odour-active compounds in air-classified fractions of faba bean (Vicia faba L. minor)

Faba bean (Vicia faba L. minor) has many interests but is characterised by off-notes (negative odours/aromas) due to volatile compounds that are promoted during seed processing. Little is known about the volatile compounds of faba bean and their contribution to its odour. The purpose of this study was to determine the volatile compound origins of air-classified fractions (flour (F), starch (S) and protein (P)) from 3 faba bean cultivars and identify the odour-active compounds. Firstly, the volatile content of the fractions was extracted by solvent-assisted flavour evaporation (SAFE) and analysed by gas chromatography-mass spectrometry (GC-MS). A total of 147 volatile compounds were detected and categorised into 12 chemical classes. The P fractions had many volatile compounds from free fatty acid (FFA) oxidation and a higher lipoxygenase (LOX) activity. The volatile content suggested that cultivar 1 (C1) was confronted with a biotic stress at field whereas cultivar 2 (C2), richer in molecules from amino acid (AA) degradation, was contaminated by microorganisms in the field. Secondly, 35 odour-active compounds (OACs) were identified by GC-olfactometry (GC-O) and 12 odour-classes were used to describe the faba bean odours. The P fractions had higher detection frequency (DF) than the S and F fractions. P2 had a more complex odour profile due to important FFA and AA degradation. This work provides a better understanding of the impact of cultivar and processing steps on the faba bean volatile content. Selection of pulse-based ingredients with low volatile compounds could improve their flavour and increase their consumption.

Fermentation Conditions Affect the Synthesis of Volatile Compounds, Dextran, and Organic Acids by Weissella confusa A16 in Faba Bean Protein Concentrate

Fermentation with Weissella confusa A16 could improve the flavor of various plant-based sources. However, less is known about the influence of fermentation conditions on the profile of volatile compounds, dextran synthesis and acidity. The present work investigates the synthesis of potential flavor-active volatile compounds, dextran, acetic acid, and lactic acid, as well as the changes in viscosity, pH, and total titratable acidity, during fermentation of faba bean protein concentrate with W. confusa A16. A Response Surface Methodology was applied to study the effect of time, temperature, dough yield, and inoculum ratio on the aforementioned responses. Twenty-nine fermentations were carried out using a Central Composite Face design. A total of 39 volatile organic compounds were identified: 2 organic acids, 7 alcohols, 8 aldehydes, 2 alkanes, 12 esters, 3 ketones, 2 aromatic compounds, and 3 terpenes. Long fermentation time and high temperature caused the formation of ethanol and ethyl acetate and the reduction of hexanal, among other compounds linked to the beany flavor. Levels of dextran, acetic acid, and lactic acid increased with increasing temperature, time, and dough yield. Optimal points set for increased dextran and reduced acidity were found at low temperatures and high dough yield. Such conditions would result in hexanal, ethyl acetate and ethanol having a relative peak area of 35.9%, 7.4%, and 4.9%, respectively.

Characterization of volatile constituents and odorous compounds in peach (Prunus persica L) fruits of different varieties by gas chromatography-ion mobility spectrometry, gas chromatography-mass spectrometry, and relative odor activity value

The aim of this study is to acquire information for future breeding efforts aimed at improving fruit quality via effects on aroma by comparing the diversity of Chinese local peach cultivars across 10 samples of three varieties (honey peach, yellow peach, and flat peach). The volatile components of peach fruits were analyzed and identified by gas chromatography–ion mobility spectrometry (GC-IMS) combined with gas chromatography–mass spectrometry (GC-MS), and the main flavor components of peach fruit were determined by relative odor activity value (ROAV) and principal component analysis (PCA). A total number of 57 volatile components were detected by GC-IMS, including eight aldehydes, nine alcohols, eight ketones, 22 esters, two acids, two phenols, two pyrazines, one thiophene, one benzene, and two furans. The proportion of esters was up to 38.6%. A total of 88 volatile components were detected by GC-MS, among which 40 were key aroma compounds, with an ROAV ≥ 1. The analysis results showed that alcohols, ketones, esters, and aldehydes contributed the most to the aroma of peach fruit. PCA demonstrated that (E,E)-2, 6-non-adienal, γ-decalactone, β-ionone, and hexyl hexanoate were the key contributors to the fruit aroma. A reference for future directional cultivation and breeding could be provided by this study through evaluating the aroma quality of the peach at the cultivar level. The possible reasonable application of these peach fruits pulp will be guided through these research.

The modification of volatile and nonvolatile compounds in lupines and faba beans by substrate modulation and lactic acid fermentation to facilitate their use for legume-based beverages-A review

Lupines and faba beans are promising ingredients for the beverage industry. They contain high amounts of protein and can be grown in different climate zones and agricultural areas. Therefore, these legumes appear as ideal raw material for vegan, functional, and sustainable beverages. Nevertheless, the sensory characteristic of legumes is generally not accepted in beverages. Therefore, the market contribution of legume-based beverages is currently only marginal. This review highlights known major flavor aspects of lupines and faba beans and the possibilities to improve these by germination, heat treatment, enzymatic treatment, and subsequent lactic acid fermentation. First, the main aroma and taste compounds are described. Thereby, the "beany" aroma is identified as the most relevant off-flavor. Second, the nutrients and antinutrients of these legumes regarding to their use as food and as substrate for lactic acid fermentation are reviewed, and possibilities to modulate the substrate are summarized. Finally, the modification of the sensory profile by lactic acid fermentation is outlined. To conclude, it seems likely that the nutritional and flavor attributes in legume-based beverages can be improved by a combined process of substrate modulation and fermentation. In a first step, antinutrients should be decomposed and proteins solubilized while transforming the solid grains into a liquid substrate. Due to such substrate modulation, a broader variety of strains could be employed and the fermentation could be based exclusively on their impact on the flavor. By applying the concept of combining a substrate modulation with a subsequent fermentation, the use of legumes in beverages could be facilitated and new products like vegan, protein-rich, refreshing beverages could be marketed.

Beneficial Effects of Sodium Nitroprusside on the Aroma, Flavors, and Anthocyanin Accumulation in Blood Orange Fruits

The quality of Tarocco blood orange (Citrus sinensis (L.) Osbeck), which has been cultivated for many years, has degraded substantially. Decreased sugar content, decreased blood color, and increased sour flavor have developed as a result. To improve fruit quality, we studied the effects of bagging and sodium nitroprusside, as a nitric oxide (NO) donor, on the fruit quality of Tarocco blood orange two months before picking. The results showed that NO treatment effectively improved the content of total soluble solids and limonene in the fruit, as well as the color and hardness of the fruit, but reduced the tannin content. It also increased the contents of soluble sugar, fructose, sucrose, vitamin C, amino acids, and mineral elements. NO treatment inhibited the activities of polygalacturonase and pectin esterase, delayed the degradation of protopectin, and promoted the accumulation of anthocyanins, total flavonoids, and flavonoids synthesis. Thus, NO treatment improved the aroma, flavors, and physical properties of blood orange fruit.

Effects of microbial diversity and phospholipids on flavor profile of caviar from hybrid sturgeon (Huso dauricus × Acipenser schrencki)

Thirty-seven volatiles were identified by gas chromatography-ion mobility spectrometry in sturgeon caviar. Alkenes (37, 43), alcohols (30, 36), aldehydes (9, 10), and esters (11, 13) were detected by two-dimensional gas chromatography-time-off-flight mass spectrometry in fresh and stored caviar, respectively. Alkenes (humulene, caryophyllene, longifolene, and d-limonene), aldehydes (heptanal, hexanal, pentanal, and 3-methyl butanal), and 2-ethyl-1-hexanol were sniffed and described as providing fresh, fatty, and fishy attributes by gas chromatography-olfactometry. The fungal genera of Apiotrichum, Penicillium, Filobasidium, Gibberella, and Cladosporium and 16 bacterial genera were significantly correlated with variations in the contents of 25 aldehydes and 11 ketones. Nine strains, 20 fatty acids, and 69 differential phospholipids were isolated and profiled. Glycerophosphoethanolamine (20:2/20:4), glycerophosphoethanolamine (22:6/22:5), and glycerophosphocholine (16:0/13:0) were significantly associated with the formation of odorants and the proposed mechanism of flavor formation from phospholipids is summarized. This study represents a foundation for achieving targeted preservation and flavor control of caviar.

Surmounting the off-flavor challenge in plant-based foods

Plant-based food products have been receiving an astronomical amount of attention recently, and their demand will most likely soar in the future. However, their unpleasant, intrinsic flavor and odor are the major obstacles limiting consumer's acceptance. These off-flavors are often described as "green," "grassy," "beany," "fatty" and "bitter." This review highlights the presence and formation of common off-flavor volatiles (aldehydes, alcohols, ketones, pyrazines, furans) and nonvolatiles (phenolics, saponins, peptides, alkaloids) from a variety of plant-based foods, including legumes (e.g. lentil, soy, pea), fruits (e.g. apple, grape, watermelon) and vegetables (e.g. carrot, potato, radish). These compounds are formed through various pathways, including lipid oxidation, ethanol fermentation and Maillard reaction (and Strecker degradation). The effect of off-flavor compounds as received by the human taste receptors, along with its possible link of bioactivity (e.g. anti-inflammatory effect), are briefly discussed on a molecular level. Generation of off-flavor compounds in plants is markedly affected by the species, cultivar, geographical location, climate conditions, farming and harvest practices. The effects of genome editing (i.e. CRISPR-Cas9), various processing technologies, such as antioxidant supplementation, enzyme treatment, extrusion, fermentation, pressure application, and different storage and packaging conditions, have been increasingly studied in recent years to mitigate the formation of off-flavors in plant foods. The information presented in this review could be useful for agricultural practitioners, fruits and vegetables industry, and meat and dairy analogue manufacturers to improve the flavor properties of plant-based foods.

Improving the Antioxidant Activity and Flavor of Faba (Vicia faba L.) Leaves by Domestic Cooking Methods

Faba leaves are an unusual vegetable which contain not only a range of functional phytochemicals, but also certain undesirable flavors, which limit their consumption. In this study, several cooking methods (microwaving, roasting, steaming, and boiling), which are expected to reduce the odd flavors, were evaluated in terms of both health benefit effects and odd flavor factors, including antioxidant activities and the content of non-volatile and volatile organic compounds (VOCs). A cooking time of 5 min was selected because of the high content of l-dopa (l-3,4-dihydroxyphenylalanine) and aim of reducing the undesirable flavors of the cooked faba leaves. Microwaving and steaming significantly increased the l-dopa content by 24% and 19%, respectively. Roasting specifically increased the content of flavonols, exhibiting a 28% increase of kaempferol-3-O-arabinoside-7-O-rhamnoside, representatively, whereas boiling decreased about 50% of most phytochemicals evaluated. Microwaving and steaming treatments significantly increased the antioxidant activities. The l-dopa content and antioxidant activities of the processed faba leaves were strongly positively correlated with either an R2 = 0.863 of DPPH radical scavenging activity or an R2 = 0.856 value of ABTS radical scavenging activity, showing that l-dopa was a key antioxidant. All cooking methods potentially improved the flavor of the cooked faba leaves compared with that of the fresh leaves, because they significantly reduced the contents of VOCs such as alcohols, aldehydes, and ketones. These VOCs were the main components (>90%) in the fresh leaves. Adverse aromatic hydrocarbons were newly formed by the microwaving treatment, typically producing p-xylene, which is known to be a harmful dose-dependent compound, but they were not detected in leaves processed by the other cooking methods; therefore, although microwaving efficiently increased antioxidant activity, the chemical safety of the aromatic hydrocarbons produced need further study.

Analyzing the Effect of Baking on the Flavor of Defatted Tiger Nut Flour by E-Tongue, E-Nose and HS-SPME-GC-MS

In order to screen for a proper baking condition to improve flavor, in this experiment, we analyzed the effect of baking on the flavor of defatted tiger nut flour by electronic tongue (E-tongue), electronic nose (E-nose) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS). According to E-tongue and E-nose radar plots and principal component analysis (PCA), baking can effectively change the taste and odor of defatted tiger nut flour, and the odors of samples with a baking time of >8 min were significantly different from the original odor of unbaked flour. Moreover, bitterness and astringency increased with longer baking times, and sweetness decreased. HS-SPME-GC-MS detected a total of 68 volatile organic compounds (VOCs) in defatted tiger nut flour at different baking levels, and most VOCs were detected at 8 min of baking. Combined with the relative odor activity value (ROAV) and heat map analysis, the types and contents of key flavor compounds were determined to be most abundant at 8 min of baking; 3-methyl butyraldehyde (fruity and sweet), valeraldehyde (almond), hexanal (grassy and fatty), and 1-dodecanol, were the key flavor compounds. 2,5-dimethyl pyrazine, and pyrazine, 2-ethylalkyl-3,5-dimethyl- added nutty aromas, and 1-nonanal, 2-heptanone, octanoic acid, bicyclo [3.1.1]hept-3-en-2-ol,4,6,6-trimethyl-, and 2-pentylfuran added special floral and fruity aromas.

Characterization, Classification, and Authentication of Polygonatum sibiricum Samples by Volatile Profiles and Flavor Properties

The importance of monitoring key aroma compounds as food characteristics to solve sample classification and authentication is increasing. The rhizome of Polygonatum sibiricum (PR, Huangjing in Chinese) has great potential to serve as an ingredient of functional foods owing to its tonic effect and flavor properties. In this study, we aimed to characterize and classify PR samples obtained from different processing levels through their volatile profiles and flavor properties by using electronic nose, electronic tongue, and headspace gas chromatography-mass spectrometry. Nine flavor indicators (four odor indicators and five taste indicators) had a strong influence on the classification ability, and a total of 54 volatile compounds were identified in all samples. The traditional Chinese processing method significantly decreased the contents of aldehydes and alkanes, while more ketones, nitrogen heterocycles, alcohols, terpenoids, sulfides, and furans/pyrans were generated in the processing cycle. The results confirmed the potential applicability of volatile profiles and flavor properties for classification of PR samples, and this study provided new insights for determining the processing level in food and pharmaceutical industries based on samples with specific flavor characteristics.