Desirable Flavor Research Articles

Addition of commercial lactic acid bacteria as starter cultures in anaerobic fermentations of Coffea arabica L., in cherry or raisin stages

The objective of this research was to verify the efficiency of adding commercial lactic acid bacteria (LAB) on anaerobic fermentation of (cherry and raisin) arabica Yellow Catuaí coffees, studying the microbiological succession and its influence in modulating sensorial characteristics on their beverages. The study took place in a rural property in Marília region, Sao Paulo State, Brasil, and was performed according to three different treatments: 1) FNC = spontaneous fermentation of cherry coffees; 2) FCBAL = cherry coffee fermentation using Sacco Lyofast SYAB1 BAL; 3) FPBAL = raisin coffee fermentation using Sacco Lyofast SYAB1 BAL. Fermentations occurred in individual (60 liters) high density polyethylene containers, properly sealed to guarantee anaerobic conditions. After a 48-hour fermentation, all the coffee fruits were washed, beans were depulped and dried on suspended terrace until a 12% humidity was observed. Physical, chemical, microbiological and sensory analysis were performed in samples collected from each fermented batch. Fermentation processes of raisin coffees occurred more slowly than fermentations using cherry coffees and resulted in a lesser consumption of soluble solids and in a slower acidification. Fermentation treatments FNC, FCBAL and FPBAL reached the necessary reduction of Enterobateriaceae and molds. The addition of BAL stimulated the growth of yeasts, which are responsible for the inclusion of the most desired flavor. The fermentations conducted in this experiment resulted in coffee beverages that reached notes of specialty coffees (> 80 points). Even though the raisin coffee achieved a lower note than cherry, the LAB inclusion raised it from 77 (non-fermented raisins) to 80 (FPBAL) points. In cherry fruits, FCBAL got 2 points on final comparation to non-fermented cherries. Thus, the inclusion of LAB presented itself beneficial to anaerobic fermentations of cherry or raisin coffees.

Enhancing the flavor quality of Chinese rice wine (Huangjiu) through inoculation with Lactobacillus plantarum and Leuconostoc mesenteroides

This study investigates the modulation of flavor in Chinese rice wine (Huangjiu) by inoculating with Lactobacillus plantarum (L. plantarum) and Leuconostoc mesenteroides (L. mesenteroides). Firmicutes and lactic acid bacteria (LAB) were predominant in both inoculated and spontaneously fermented samples. We observed an enhanced bacterial diversity in treatments involving single and combined inoculations, which corresponded with increases in volatile components, organic acids, and amino acids compared to spontaneously fermented controls. Sensory evaluations, assessing alcohol aroma, sourness, and full-bodiedness, identified the co-inoculated samples as superior, outperforming those from single inoculations and spontaneous fermentations. These results elucidate the impact of starter cultures on the fermentation process and flavor profile of Huangjiu, providing insights for selecting optimal starters to engineer desired flavor characteristics.

Screening appropriate lactic acid bacteria as adjunct starter to enhance characteristic flavor and sensory profiles of Huangjiu (Chinese rice wine)

Lactic acid bacteria (LAB) are crucial for enhancing Huangjiu flavor, yet no standardized criteria exist for selecting LAB strains for this purpose. This study aimed to investigate the suitability of screening appropriate LAB strains as adjunct starters for Huangjiu fermentation. Twenty-five LAB strains were assessed for their stress resistance and fermentation characteristics. Co-fermentation with Saccharomyces cerevisiae was conducted to explore its role in flavor development, as this yeast greatly contribute to desirable flavor profiles. Notably, Lactiplantibacillus plantarum AR1018, AR1026 and Weissella confusa AR1038 significantly reduced 3-methyl-1-butanol production while increasing levels of ethyl hexanoate and ethyl octanoate. These strains were selected for further analysis of their impact on the physicochemical properties, volatile organic compounds, and sensory attributes of Huangjiu. The LAB starters enhanced total acidity, sugar and protein utilization and ester synthesis, while reducing ethanol and alcohol levels. AR1018 achieved a 16.51% reduction in 3-methyl-1-butanol, whereas AR1038 exhibited a 27.32% increase in ester content compared to the control. Principal component analysis revealed distinct flavor characteristic between Huangjiu produced with AR1018 and AR1038, and sensory evaluation confirmed enhanced desirable attributes, especially for AR1038. This study highlights the potential of LAB starters in improving the flavor quality of rice wine and similar fermented beverages.

Impact of solar pre-drying and yeast starter inoculation treatments on volatile compounds in cocoa (Theobroma cacao L.) beans from Southwestern Colombia

In the region of Tumaco (Nariño, Colombia), in Southwestern Colombia, the CCN-51 cocoa clone has been commonly cultivated in recent decades. Determining the influence of cocoa processing conditions (pre-drying and yeast starter inoculation) on the profile of volatile compounds is essential to ensure maximum cocoa quality. To this aim, cocoa beans were fermented following four different treatments: (1) spontaneously (at room temperature for 120 h) in traditional conditions (control; CO); (2) traditional processing with a pre-drying (sun-dried for 24 h) treatment (PD); (3) with fermentation (for 120 h) after inoculation of a yeast starter culture (YS); and (4) including both treatments, pre-drying and yeast inoculation (PD+YS). A total of 45 volatile compounds were identified by SPME-HS/GC–MS and classified as: alcohols (9), aldehydes and ketones (17), acids (6), esters (3), pyrazines (2), aliphatic hydrocarbons (4) and others (4). Pre-drying and yeast starter inoculation reduced the concentration of acids, which are associated with off-flavour notes. Fermentation with a selected yeast culture generated desirable flavour notes (sweet, fruity, floral, buttery and malty). The PCA score plot showed a clear separation of the samples obtained from the different treatment studied. In conclusion, pre-drying and inoculating with selected yeasts during processing help enhance the sensory quality of the cocoa.

The impact of hot-air oven drying combined with Bacillus subtilis K[sbnd]C3 inoculation on quality characteristics and microbial profiles of salted shrimp paste

This study used hot-air oven drying with Bacillus subtilis KC3 inoculation to improve shrimp paste production. The fermentation rate, quality characteristics, as well as microbial profiles, were compared to those produced using sun-drying with/without inoculation. B. subtilis inoculation increased the degree of hydrolysis of shrimp paste (22.3–32.1 %) during fermentation, compared to those without inoculation (12.7–25.4 %), regardless of different drying methods (p < 0.05). The result corresponded to the faster development of shrimp paste characteristics, particularly color and browning intensity of inoculated samples when fermented for the same duration. More abundant halophilic, proteolytic, and lipolytic bacteria (p < 0.05) were also obtained in inoculated samples, confirming accelerated fermentation. Interestingly, there was no difference in proximate composition, pH, and aw among samples (p > 0.05), which were still in the range regulated by the product's standard. However, the protein and lipid degradation products such as nitrogen contents, 5′-nucleotides, free fatty acids or TBARS values, varied among samples, potentially influencing the release of desirable flavor precursors to a certain extent. The inoculation increased microbial richness and evenness/uniformity, according to next-generation sequencing analysis on microbiota profiles. Pearson's correlation also revealed that these microbiota profiles were correlated with several desirable quality characteristics to varying degrees. Thus, combining the inoculation with B. subtilis KC3 can enhance shrimp paste fermentation and quality when produced using an alternative hot-air oven while maintaining quality characteristics. The findings suggested the possibility of achieving a more efficient and consistent production process for shrimp paste.

Sensory analysis of the flavor profile of full immersion hot, room temperature, and cold brewed coffee over time

With the growing popularity of cold brewed coffee comes a need for brewing efficiency while preserving the desirable flavor profile. Despite the wide use of full immersion brewing techniques, the effect of brew time on the dynamic sensory profiles of full immersion brewed coffee remains underexplored. Here, we investigated the relationship between coffee sensory quality and extraction dynamics, measured as Total Dissolved Solids (TDS) and Extraction (E) of full immersion brewed coffee at various roast levels, and brewing temperatures (4 °C, 22 °C and 92 °C), over brew time using a generic descriptive analysis method. Specifically, different brew time points were selected for different temperatures based on five targeted coffee extraction stages. Furthermore, the unique experimental design also explored a sensory-driven engineering research process. Roast level had the greatest impact on the sensory profile of the coffees, followed by brewing temperature, but brew time, especially the longer brew times as TDS plateaued, had subtler impacts than expected. Twenty-five of 28 sensory attributes were significantly different among the 30 coffee samples, indicating a single source green coffee blend can produce a wide range of complex sensory profiles using different combinations of roast level, temperature, and brew time. Specifically, the intensity of sweetness was negatively correlated with TDS, and 19 other attribute intensities were positively correlated with TDS. Interestingly, we found that certain long time cold brews had similar sensory profiles to those of some short time hot brews, suggesting the sensory profiles of certain hot brews and cold brews could possibly be matched through controlled preparation. Overall, our study demonstrated an approach of integrating food engineering and sensory analysis for product development, and our findings provide valuable insights into the extraction dynamics and sensory quality of full immersion brewed coffee and opens new brewing avenues for the coffee industry.

Managing fruit rot diseases of Vaccinium corymbosum.

Blueberry is an important perennial fruit crop with expanding consumption and production worldwide. Consumer demand for blueberries has grown due to the desirable flavor and numerous health benefits, and fresh market production in the U.S. has risen in turn. U.S. imports have also increased to satisfy year-round consumer demand for fresh blueberries. Pre- and post-harvest fruit diseases such as anthracnose (caused by Colletotrichum spp.) and botrytis fruit rot (caused by Botrytis spp.) have a significant impact on fruit quality and consumer acceptance. These are also among the most difficult diseases to control in the blueberry cropping system. These latent pathogens can cause significant losses both in the field, and especially during transport and marketplace storage. Although both diseases result in rotted fruit, the biology and infection strategies of the causal pathogens are very different, and the management strategies differ. Innovations for management, such as improved molecular detection assays for fungicide resistance, postharvest imaging, breeding resistant cultivars, and biopesticides have been developed for improved fruit quality. Development and integration of new strategies is critical for the long-term success of the blueberry industry.

Impact of Different Carbon Sources on Volatile Organic Compounds (VOCs) Produced during Fermentation by Levilactobacillus brevis WLP672 Measured Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS).

Bacterial fermentation is considered to be a cost-effective means of generating desired flavour compounds from plant-based substrates. However, the wide range of substrates present in plants makes it challenging to understand how individual components impact on flavour volatile organic compound (VOC) production. To simplify this, a defined medium can be used to better understand VOCs production with regard to individual compounds. In the current study, the VOCs produced by the lactic acid bacterium, Levilactobacillus brevis WLP672, growing in a defined medium containing different carbon sources (either glucose (DM), fructose (DMFr) or citrate (DMCi)) under a range of fermentation conditions (time: 0, 7, and 14 days; and temperature: 25 and 35 °C) were assessed using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Among the detected mass peaks (m/z), after 7 days of fermentation, the concentrations of m/z 45.033 (t.i. acetaldehyde), m/z 49.011 (t.i. methanethiol), and m/z 89.060 (t.i. ethyl acetate) were significantly (p < 0.05) higher in DM at 35 °C than all other treatments at either temperature. The knowledge obtained will help to produce desirable LAB fermentation flavour VOCs or VOC mixtures that could be used in developing plant-based analogues with acceptable sensory properties.

Strawberry field trial in Australia demonstrates improvements to fruit yield and quality control conformity, from application of two biostimulant complexes

ABSTRACT Strawberry (Fragaria x ananassa) is a popular fruit consumed for its desirable flavour, aroma and colour and is considered a functional food due to its antioxidant properties. Noting the need for farmers to increase productivity to meet increasing consumer demands, this study aimed to explore the potential of biostimulants to enhance strawberry cultivation. Herein, a field trial was conducted on a commercial strawberry farm, wherein 1944 strawberry plants received fertigation supplementation with either a control solution (nutrients only) or nutrients combined with one of two biostimulant complexes (BCs). Biostimulant complex 1 (BC1) was composed of molasses, Aloe vera extract and fish-hydrolysate, and biostimulant complex 2 (BC2) was composed of potassium silicate and potassium phosphite. Results indicated that BC1 maintained total yields but increased the sellable proportion and decreased the proportion of waste. In contrast, BC2 increased total yields with both sellable yields and waste increased. No significant changes were observed for indicators of consumer preference (flavour, aroma and fruit colour), however, on-average large increases were observed to indicators of fruit antioxidant properties (phenolic and flavonoid content). Accordingly, these results support the utilisation of biostimulants as a strategy to improve strawberry on-farm productivity without compromising consumer quality measures.

Dung Beetle Optimizer Algorithm and Machine Learning-Based Genome Analysis of Lactococcus lactis: Predicting Electronic Sensory Properties of Fermented Milk.

In the global food industry, fermented dairy products are valued for their unique flavors and nutrients. Lactococcus lactis is crucial in developing these flavors during fermentation. Meeting diverse consumer flavor preferences requires the careful selection of fermentation agents. Traditional assessment methods are slow, costly, and subjective. Although electronic-nose and -tongue technologies provide objective assessments, they are mostly limited to laboratory environments. Therefore, this study developed a model to predict the electronic sensory characteristics of fermented milk. This model is based on the genomic data of Lactococcus lactis, using the DBO (Dung Beetle Optimizer) optimization algorithm combined with 10 different machine learning methods. The research results show that the combination of the DBO optimization algorithm and multi-round feature selection with a ridge regression model significantly improved the performance of the model. In the 10-fold cross-validation, the R2 values of all the electronic sensory phenotypes exceeded 0.895, indicating an excellent performance. In addition, a deep analysis of the electronic sensory data revealed an important phenomenon: the correlation between the electronic sensory phenotypes is positively related to the number of features jointly selected. Generally, a higher correlation among the electronic sensory phenotypes corresponds to a greater number of features being jointly selected. Specifically, phenotypes with high correlations exhibit from 2 to 60 times more jointly selected features than those with low correlations. This suggests that our feature selection strategy effectively identifies the key features impacting multiple phenotypes, likely originating from their regulation by similar biological pathways or metabolic processes. Overall, this study proposes a more efficient and cost-effective method for predicting the electronic sensory characteristics of milk fermented by Lactococcus lactis. It helps to screen and optimize fermenting agents with desirable flavor characteristics, thereby driving innovation and development in the dairy industry and enhancing the product quality and market competitiveness.

The Influence of Cooking Methods and Muscle on Beef Aroma Profile and Consumer Satisfaction: Insights from Volatile Compound Analysis

The objective of this study is to determine the effect of two distinct cooking techniques, namely roasting and stewing, on the formation of volatile compounds in various beef muscles (Semimembranosus, Biceps femoris, and Rectus femoris) and how this relates to consumer acceptance. The research employs the concept of volatile “marker” compounds to discern the influence of cooking techniques on the flavor profile of beef. Eighteen “marker compounds” were selected to represent a number of the mechanisms of formation and quantified in beef subjected to two different cooking methods. While no statistically significant differences were observed in consumer evaluations between the two cooking methods, notable disparities emerged in the consumer assessments of specific muscle cuts. Notably, the Rectus femoris muscle received the highest ratings (p &lt; 0.05) among other evaluated muscles. The utilization of Solid-Phase Microextraction (SPME) and gas chromatography–mass spectrometry (GC-MS) methods for the analysis of volatile “marker compounds” in beef proved effective in highlighting significant differences in flavor compound classes between cooking methods, and these differed between muscles. The main effect was of the cooking method with stewed beef aroma having approximately 39× more dimethyl trisulphide, 9× more dimethyl disulphide, 7× more pentanal, 3× more hexanal, and twice as much benzaldehyde and 2-methylthiophene. Dimethyldisulphide, dimethyltrisulphide, hexanal, and heptanal, therefore, emerged as characteristic volatile compounds associated with the stewing cooking technique, suggesting their potential as markers for lipid and other oxidation reactions. This work indicates that certain lipid oxidation compounds, Strecker aldehydes, and sulfur compounds can be markers for the undesirable and/or desirable flavors of cooked beef, but that this depends on the cooking method chosen. It shows that flavor differences may be understood through the analysis of volatile flavor compounds in association with palatability and other chemical measurements.

Characterization of the Non-Volatiles and Volatiles in Correlation with Flavor Development of Cooked Goat Meat as Affected by Different Cooking Methods.

Thai-Native×Anglo-Nubian goat meat cooked by grilling (GR), sous vide (SV), and microwave (MW), was compared to fresh meat (Raw) in terms of flavor development. Non-volatile [i.e., free amino acids, nucleotide-related compounds, taste active values (TAVs) and umami equivalency, sugars, lipid oxidation, Maillard reaction products] and volatile compounds, were investigated. Notably, inosine monophosphate and Glu/Gln were the major compounds contributing to umami taste, as indicated by the highest TAVs in all samples. Raw had higher TAVs than cooked ones, indicating that heat-cooking removes these desirable flavor and taste compounds. This could be proportionally associated with the increase in aldehyde, ketone, and nitrogen-containing volatiles in all cooked samples. GR showed the highest thiobarbituric acid reactive substances (1.46 mg malonaldehyde/kg sample) and browning intensity (0.73), indicating the greatest lipid oxidation and Maillard reaction due to the higher temperature among all cooked samples (p<0.05). In contrast, SV and Raw exhibited similar profiles, indicating that low cooking temperatures preserved natural goat meat flavor, particularly the goaty odor. The principal component analysis biplot linked volatiles and non-volatiles dominant for each cooked sample to their unique flavor and taste. Therefore, these findings shed light on cooking method selection based on desirable flavor and preferences.

The mechanism of low temperature enhances dough aromas during fermentation by Pichia kudriavzevii: Sugar and amino acid metabolism, acid utilization and alcohol production

In order to investigate the impact of low temperature on enhancing aromas in fermented dough by Pichia kudriavzevii CGMCC 17607 (EP), the study initially utilized gas chromatography to detect volatile organic compounds (VOCs), followed by analyzing basal metabolites derived from these VOCs. Metabolomics was employed to monitor metabolic changes during fermentation, while proteomics was used to examine protein expression related to these changes. Results indicated notable increases in VOCs such as 3-methyl-1-butanol and 2-phenylethanol. Essential metabolites exhibited decreases in sugars (e.g., sucrose, maltose), organic acids (e.g., lactic acid, acetic acid), and amino acids (e.g., leucine, histidine). Particularly, low temperature fermentation led to raised levels of NAD+, NADH, acyltransferases, and ATP, excluding pyruvic acid and glucose-6-phosphate dehydrogenase. These outcomes suggested that low temperature fermentation boosted acid utilization and alcohol production. Metabolomics and proteomics highlighted decreased glycolysis influencing energy metabolism. Moreover, metabolomics revealed elevated levels of flavor substances like octanoic acid and its derivatives with aromatic properties, as well as geranic acid with terpenoid aroma. Furthermore, key intermediates like chorismite and phenylpyruvic acid, along with the pivotal enzyme chorismate synthase, illustrated the biosynthesis pathway of shikimic acid instead of phenylalanine. In summary, at low temperature, EP showed weakened glycolysis, with sugars and amino acids metabolizing into desirable flavor substances like alcohols, which promoted acidity reduction and aroma enhancement of dough.

Analysis of volatile organic compounds in Korean-bred strawberries: insights for improving fruit flavor.

The strawberry industry in South Korea has witnessed a significant 65% growth over the past decade, surpassing other fruits and vegetables in production value. While sweetness and acidity are well-recognized flavor determinants, the role of volatile organic compounds (VOCs) in defining the desirable flavor profiles of strawberries is also crucial. However, existing research has predominantly concentrated on a limited range of commercial cultivars, neglecting the broader spectrum of strawberry varieties. This study embarked on developing a comprehensive VOC database for a diverse array of strawberry cultivars sourced both domestically and internationally. A total of 61 different strawberry cultivars from Korea (45), the USA (7), Japan (8), and France (1) were analyzed for their VOC content using Tenax TA Thermo Desorption tubes and Gas Chromatography-Mass Spectrometry (GC-MS). In addition to VOC profiling, heritability was assessed using one-way ANOVA to compare means among multiple groups, providing insights into the genetic basis of flavor differences. The analysis identified 122 compounds categorized into esters, alcohols, terpenes, and lactones, with esters constituting the majority (46.5%) of total VOCs in Korean cultivars. 'Arihyang', 'Sunnyberry', and 'Kingsberry' exhibited the highest diversity of VOCs detected (97 types), whereas 'Seolhong' showed the highest overall concentration (57.5mg·kg-1 FW). Compared to the USA cultivars, which were abundant in γ-decalactone (a peach-like fruity aroma), most domestic cultivars lacked this compound. Notably, 'Misohyang' displayed a high γ-decalactone content, highlighting its potential as breeding germplasm to improve flavor in Korean strawberries. The findings underscore the importance of a comprehensive VOC analysis across different strawberry cultivars to understand flavor composition. The significant variation in VOC content among the cultivars examined opens avenues for targeted breeding strategies. By leveraging the distinct VOC profiles, particularly the presence of γ-decalactone, breeders can develop new strawberry varieties with enhanced flavor profiles, catering to consumer preferences for both domestic and international markets.

Effects of relative humidity on dry-aged beef quality

This study was conducted to evaluate the effects of relative humidity (RH) on moisture loss and flavor in dry-aged beef. Sixteen strip loins were assigned to one of the four aging treatments: vacuum (WET), dry-aging at 50% RH, dry-aging at 70% RH, or dry-aging at 85% RH and aged for 42 days at 2 °C. Loins were evaluated for evaporation loss, trim loss, tenderness, sensory, and microbiological characteristics. Results show that lower RH results in accelerated moisture loss during the first 3 days of the aging process without significantly affecting the total amount of moisture loss. Pseudomonadales dominated the aerobically dry-aged loins while Enterobacteriales was the most abundant in the wet-aged samples. Dry-aged samples had increased content of free amino acids in the cooked meat juice compared to the wet-aged counterpart. Dry aging at 50% RH tended to associate with more desirable flavor notes.

Lactiplantibacillus plantarum ZFM55 improves texture and flavor of yogurt, increases beneficial metabolites, and the co-fermented yogurt promotes human gut microbiota health

Yogurt offers potential health benefits, particularly for the intestines. The choice of starter culture is key to the production of functional yogurt. In this study, Lactiplantibacillus plantarum ZFM55 was incorporated into a commercial starter and its effects on the quality of yogurt was evaluated. Changes in texture, flavor, composition, and metabolites were assessed, along with its impact on the gut microbiota. We found adding ZFM55 improved the water holding capacity, cohesiveness, viscosity, and hardness of the yogurt. Analysis using gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) and liquid chromatography-mass spectrometry (LC-MS) demonstrated that ZFM55 contributed to a desirable flavor profile and increased the levels of non-volatile metabolites, such as amino acids and carbohydrates. Stool samples from volunteers who consumed fermented milk were collected and analyzed using 16 S rDNA sequencing and GC-MS. The results showed that fermenting yogurt with ZFM55 significantly altered the beta diversity of the gut microbiota. Notably, probiotics such as Bifidobacterium, Blautia, and Lactobacillus exhibited substantial increases, along with a notable rise in the production of short-chain fatty acids, particularly acetic acid and butyric acid. These findings highlight the potential of ZFM55 for developing high-quality functional yogurt products.

Far-red Light and Nitrogen Concentration Elicit Crop-specific Responses in Baby Greens under Superelevated CO2 and Continuous Light

Baby greens are becoming increasingly popular in the consumer market because of their desired flavor and leaf size. The short life cycles and fast response times to environmental stimuli make baby greens ideal for testing environmental conditions for space crop production. Additionally, far-red (FR) light has been used for microgreen and baby green research to enhance stem elongation, leaf expansion, and biomass; however, how it interacts with nutrient solution nitrogen (N) concentrations remains unclear. During this ground-based study, we characterized how FR light and N concentrations influenced the growth and morphology of Chinese cabbage (Brassica rapa var. chinensis cv. Tokyo Bekana) and kale (Brassica oleracea var. sabellica cv. Red Russian) baby greens under similar superelevated CO2 and low relative humidity to levels observed in spaceflight. Plants were subject to combinations of four sole-source light spectra and three N concentrations (75, 125, and 175 mg⋅L−1). At the same total photon flux density (PFD) of 200 μmol⋅m−2⋅s−1, we maintained the same blue and green PFDs at 25 μmol⋅m−2⋅s−1 each; the remaining 150 μmol⋅m−2⋅s−1 comprised four red (R) and FR PFD combinations (FR: 0, 25, 50, and 75 μmol⋅m−2⋅s−1). Increasing the FR PFD enhanced the typical shade-avoidance morphology of Chinese cabbage ‘Tokyo Bekana’ and kale ‘Red Russian’, exhibiting leaf length increases of 20% to 26% and 31% to 61%, respectively. Edible biomass did not increase with increasing FR PFDs for either species, regardless of the N concentration. Increasing the N concentration increased the Chinese cabbage ‘Tokyo Bekana’ fresh mass and dry mass by 32% to 59% and 37% to 74%, respectively, except under 25 μmol⋅m−2⋅s−1 of FR light, with which shoot fresh mass increased by 55% with an increasing N concentration from 75 to 125 mg⋅L−1; however, the shoot dry mass was unaffected. Increasing the N concentration did not affect kale ‘Red Russian’ growth under various FR PFDs. We conclude that partially substituting incremental FR light for R light elicits the shade-avoidance response, with little influence on the growth, of Chinese cabbage ‘Tokyo Bekana’ and kale ‘Red Russian’ baby greens under superelevated CO2 and continuous light, and that the former, but not the latter, crop can benefit from increased N fertilization.

Formation and distribution of (E,E)‐2,4‐decadienal in deep‐fried dough sticks under different conditions

Abstract(E,E)‐2,4‐Decadienal is an important product of deep‐frying systems and is regarded as a health hazard. The present study investigated the formation of (E,E)‐2,4‐decadienal in deep‐fried dough sticks under different conditions, including types of deep‐frying oils, deep‐frying temperature, and dough composition. In addition, the correlation between (E,E)‐2,4‐decadienal formation and deep‐frying conditions was analyzed. The results showed that the (E,E)‐2,4‐decadienal content in the deep‐frying system was related to the linoleic acid level in the deep‐frying oils. Furthermore, adding 6% soy protein isolate to the dough considerably suppressed the formation of (E,E)‐2,4‐decadienal in the deep‐frying system, resulting in the lowest content at 43.52 mg kg–1. The highest (E,E)‐2,4‐decadienal content in the deep‐frying system (64.65 mg kg–1) was observed when a dough with a moisture content of 38% was used. The results of the correlation analysis revealed a strong association between the (E,E)‐2,4‐decadienal content in the deep‐fried dough sticks and their oil absorption capacity. The (E,E)‐2,4‐decadienal content increased with higher oil content in the deep‐fried dough sticks. Therefore, suppressing the oil absorption of deep‐fried dough sticks is an important approach for controlling (E,E)‐2,4‐decadienal content.Practical applications: As one kind of traditional deep‐fried foods in China, deep‐fried dough sticks attracted the attention of consumers because of its desirable flavor and texture. Thus, it is crucial to improve its safety and quality. As is known, (E,E)‐2,4‐decadienal is harmful to health, and it is the main aldehyde component in the deep‐frying system. Herein, it is important to improve the safety of deep‐fried dough sticks while suppressing the formation of (E,E)‐2,4‐decadienal in deep‐frying system and reducing the content of (E,E)‐2,4‐decadienal in deep‐fried dough sticks. On the one hand, the use of deep‐frying oils with lower level of linoleic acid could limit the formation of (E,E)‐2,4‐decadienal in deep‐frying system, which could also be achieved with the addition of protein into the dough. On the other hand, suppressing the oil uptake ability of deep‐fried dough sticks is an important approach to limit the level of (E,E)‐2,4‐decadienal in deep‐fried dough sticks.

Volatile Organic Compounds (VOCs) Produced by Levilactobacillus brevis WLP672 Fermentation in Defined Media Supplemented with Different Amino Acids.

Fermentation by lactic acid bacteria (LAB) is a promising approach to meet the increasing demand for meat or dairy plant-based analogues with realistic flavours. However, a detailed understanding of the impact of the substrate, fermentation conditions, and bacterial strains on the volatile organic compounds (VOCs) produced during fermentation is lacking. As a first step, the current study used a defined medium (DM) supplemented with the amino acids L-leucine (Leu), L-isoleucine (Ile), L-phenylalanine (Phe), L-threonine (Thr), L-methionine (Met), or L-glutamic acid (Glu) separately or combined to determine their impact on the VOCs produced by Levilactobacillus brevis WLP672 (LB672). VOCs were measured using headspace solid-phase microextraction (HS-SPME) gas chromatography-mass spectrometry (GC-MS). VOCs associated with the specific amino acids added included: benzaldehyde, phenylethyl alcohol, and benzyl alcohol with added Phe; methanethiol, methional, and dimethyl disulphide with added Met; 3-methyl butanol with added Leu; and 2-methyl butanol with added Ile. This research demonstrated that fermentation by LB672 of a DM supplemented with different amino acids separately or combined resulted in the formation of a range of dairy- and meat-related VOCs and provides information on how plant-based fermentations could be manipulated to generate desirable flavours.

Characterization and discrimination of volatile organic compounds and α-glucosidase inhibitory activity of soybeans (Glycine max L.) during solid-state fermentation with Eurotium cristatum YL-1

In this study, the influence of solid-state fermentation (SSF) using probiotic Eurotium cristatum on the change of volatile organic compounds (VOCs) and α-glucosidase inhibition activity of soybeans was investigated. A total of 46 VOCs were characterized via headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), the majority of which were aldehydes (17), alcohols (10), and ketones (7). SSF by E. cristatum drastically affected the flavor characteristics of soybeans, and the levels of unpleasant beany flavor components, such as hexanal-D, 1-octen-3-ol, 1-hexanol-D, 1-hexanol-M, heptanal-M, 1-pentanol, heptanal-D, and 2-pentyl furan were all substantially decreased by 50% after 15 days of SSF, while volatiles with floral, caramel, and desirable flavors such as pentanal-D, methylpropanal, 2-propanol, and propyl acetate drastically (p < 0.05) increased by 1.1-, 19.2-, 3.6-, and 2.6-fold, respectively. Key aroma-active compounds analysis revealed that 18 VOCs (ROAV, relative odor activity value ≥ 1) play a great role in shaping the flavor characteristics of the soybean samples. After 15 days of SSF, the ROAV values of methylpropanal, 2-propanol, and propyl acetate drastically (p < 0.05) increased to 8.48, 63.88, and 11.29, respectively, which greatly contributed to the desirable flavor characteristics of fermented soybeans. Furthermore, E. cristatum greatly improved the α-glucosidase inhibitory activity of soybean by 22.4% after 15 days fermentation, which was closely correlated with the accumulated phenolic compounds during SSF. Molecular docking showed that genistein and daidzein have high binding affinity for α-glucosidase active sites, primarily driven by hydrogen bonds and hydrophobic interactions. These results demonstrated that soybeans fermented with E. cristatum substantially improved the flavor characteristics and α-glucosidase inhibitory effect, and were greatly helpful to promote the application of soybeans in food products.