Search Results (81)

Black tea is widely consumed worldwide, and its characteristic taste and color result from fermentation, where polyphenols are enzymatically oxidized to generate major pigments, including theaflavins (TFs), thearubigins (TRs), and theabrownins (TBs). This study investigated the effects of increased oxygen treatment during fermentation on the flavor attributes and chemical properties of Congou black tea. Fresh tea leaves (variety “Fuyun 6”) were subjected to four oxygen treatments: 0 h (CK), 1 h (TY-1h), 2 h (TY-2h), and 3 h (TY-3h), with oxygen supplied at 8.0 L/min. Sensory evaluation revealed that oxygen-treated samples exhibited tighter and deeper-colored leaves, a redder liquor, fuller taste, and a sweeter fragrance compared with CK. Chromatic analysis showed significant increases in redness (a*) and luminance (L*), alongside reduced yellowness (b*), indicating enhanced liquor color. Chemical analyses demonstrated elevated levels of TFs, TRs, and TBs in oxygen treatments, with TRs showing the most pronounced increase. Non-targeted metabolomics identified 2318 non-volatile and 761 volatile metabolites, highlighting upregulated flavonoids, phenolic acids, and lipids, and downregulated catechins and tannins, which collectively contributed to improved taste and aroma. Optimal results were achieved with 2–3 h of oxygen treatment, balancing pigment formation and sensory quality. These findings can provide a scientific basis for optimizing oxygen conditions in black tea fermentation to improve product quality. Full article

Coffee is one of the most widely consumed beverages worldwide, primarily due to the stimulating effects attributed to its caffeine content. However, excessive intake of caffeine results in negative effects, including palpitations, anxiety, and insomnia. Therefore, low-caffeine coffee has captivated growing consumer interest, highlighting its significant market potential. Traditional decaffeination methods often lead to non-selective extraction, resulting in a loss of desirable flavor compounds, thereby compromising coffee quality. In recent years, microbial fermentation has emerged as a promising, targeted, and safe approach for reducing caffeine content during processing. Additionally, mixed-culture fermentation further enhances coffee flavor and overcomes the drawbacks of monoculture fermentation, such as low efficiency and limited flavor profiles. Nonetheless, several challenges are yet to be resolved, including microbial tolerance to caffeine and related alkaloids, the safety of fermentation products, and elucidation of the underlying mechanisms behind microbial synergy in co-cultures. This review outlines the variety of microorganisms with the potential to degrade caffeine and the biochemical processes involved in this process. It explores how microbes tolerate caffeine, the safety of metabolites produced during fermentation, and the synergistic effects of mixed microbial cultures on the modulation of coffee flavor compounds, including esters and carbonyls. Future directions are discussed, including the screening of alkaloid-tolerant strains, constructing microbial consortia for simultaneous caffeine degradation for flavor enhancement, and developing high-quality low-caffeine coffee. Full article

Mung bean (Vigna radiata L.) is globally cultivated and has been widely used in the food industries. Other than nutrients, the composition of the volatile organic compounds (VOCs) often influences the quality of mung bean-based products. However, the dynamics of VOCs and the flavor changes during mung bean seed development remain unexplored. This study investigated the VOC and flavor composition in four mung bean varieties by integrating relative odor activity value (ROAV) evaluation and transcriptomic analysis. A total of 65 VOCs were identified, with eucalyptol serving as a key maturity indicator in LL655 and SH-1, while nonanal contributed significantly to the characteristic beany flavor across all varieties. Transcriptomic analysis revealed four downregulated geranylgeranyl diphosphate synthase genes during seed development, leading to terpenoid accumulation patterns. Terpenoids, including trans-beta ocimene and gamma-terpinene, appeared to be regulated by transcription factors (TFs) from the RLK-Pelle, WRKY, AP2/ERF, bHLH, and bZIP families. Additionally, two MYB TFs showed potential roles in modulating the accumulation of phenylpropanoid/benzenoid derivatives. This study provides a comprehensive understanding of the VOC accumulation and flavor variation during mung bean seed development, enriches the knowledge of flavor chemistry in mung bean varieties, and facilitates a theoretical foundation for optimizing and developing mung bean-based products. Full article

Dragon fruit comprises a wide variety of species that are rich in nutritional value and have great economic potential; however, numerous studies have focused on their nutritional and commercial quality. In contrast, few studies have addressed their flavor quality, particularly with respect to the regulatory networks responsible for their flavor-related substance contents. To this end, we sequenced the transcriptomes and metabolomes of red-skin/white-fleshed and red-skin/red-fleshed dragon fruit at different timepoints during fruit development. RNA-seq and metabolome data were used to divide the seven developmental stages of the dragon fruit into four categories (young fruit, expansion, maturity, and senescence). In all, 16,827 differentially expressed genes (DEGs), including 958 transcription factors, were identified and grouped into 10 clusters, and the pathways in each cluster were annotated. Additionally, 318 differentially accumulated metabolites (DAMs) were identified, including 88 common metabolites. The main flavor-related substances and the key genes regulating them were determined via joint analysis via RNA-seq and metabolomics. Furthermore, 10 volatile active components related to green flavors and aromas were screened according to the relative odor activity value (ROAV), and 15 candidate genes related to key flavor compounds were screened via WGCNA, 3 of which encoded transcription factors. In conclusion, our results provide a theoretical basis for an in-depth understanding of the volatile flavor compounds in dragon fruit and provide new genetic resources for the subsequent study of fruit flavor compounds. Full article

Cheese is a globally consumed dairy product, with Europe leading the world in its consumption. Italy, as the third-largest cheese producer within the European Union, plays a crucial role in the sector, particularly through its production of Protected Designation of Origin (P.D.O.) cheeses, including Grana Padano and Parmigiano Reggiano. These hard cheeses are widely utilized in pre-packaged grated cheese products, owing to their broad appeal and recognized quality. While mold is a common and often necessary component in cheese production for the development of flavor and texture, fungal growth can also detrimentally affect the quality of cheese, potentially causing economic losses and posing food safety risks. Some molds are capable of producing mycotoxins, such as ochratoxin A (OTA), a toxic compound that has been identified in cheese. This study aims to quantitatively assess the prevalence of OTA contamination in various pre-packaged grated cheese products using the high-performance liquid chromatography method while also exploring the potential implications for food safety. The results revealed a high incidence of OTA, with 97.6% of the samples tested positive for contamination, ranging from below the limit of detection (<LOD) to 19.15 ng g⁻¹. Among the cheeses tested, the Parmigiano Reggiano brand exhibited the significantly highest average level of OTA contamination (5.06 ± 0.66 ng g⁻¹), followed by pecorino (2.25 ± 0.31 ng g⁻¹), mixed (2.15 ± 0.18 ng g⁻¹), and the Grana Padano cheeses (1.53 ± 0.21 ng g⁻¹). Given the widespread consumption of pre-packaged grated cheese products, these findings underscore the importance of continuous monitoring and risk assessment of cheese products, particularly pre-packaged grated varieties, due to the potential health risks associated with OTA exposure. Further investigations are essential to identify the factors contributing to OTA contamination in cheese and to support the development of regulatory standards to ensure consumer safety. Full article

Many aromatic herbs are conventionally used for flavoring various foods, but receive wide attention because of the variety of health-related properties. The aromatic herbs can be used either fresh or as dried powders and in the form of extracts, essential oils, or purified metabolites. In this review, the main functional properties, in terms of antioxidant and antimicrobial properties, and the applications of some of the commonly used aromatic herbs from the Lamiaceae family, are discussed. Herbs like oregano, rosemary, sage, thyme, summer savory, marjoram, and basil possess high levels of bioactive phytochemicals. They are particularly rich in phenolic acids, flavones, phenolic diterpenes, and flavanones, with various beneficial effects. The phytochemical profile of aromatic plants is highly influenced by genetic factors, environmental conditions, and their interaction. In cases of the extracts and essential oils, the extraction method has a strong effect on the final composition of the herb products. Most of the applications of these aromatic herbs are related to their antioxidant, antimicrobial, and flavoring properties. In particular, aromatic herb extracts and essential oils have multiple applications in fields like food, feed, pharmaceutical, cosmetics, biopesticides, and textile industries. Full article

Apricot cultivation plays a significant role in Italy’s agricultural landscape, with the country hosting a wide variety of traditional and international cultivars, and their cultivation, processing and transformation offer a wide margin for market expansion. Jam preparation is an ideal method to preserve apricots, and understanding their functional properties is crucial for achieving high-quality products. Vesuvian autochthonous cultivars, in particular, stand out for their unique organoleptic and nutraceutical traits, which are closely linked to the region’s pedo-climatic conditions. This study investigated two apricot cultivars, the Vesuvian ‘Pellecchiella’ and the international ‘Lady Cot’, to assess their physicochemical properties and evaluate the variation in bioactive components during the transformation process from fresh fruit to puree and jam. The two cultivars exhibited distinct phenotypic differences. The ‘Lady Cot’ produced larger fruits (61.04 g vs. 45.68 g for the ‘Pellecchiella’) with a redder epicarp coloration, making it more visually appealing for commercial purposes. Conversely, the ‘Pellecchiella’ showed higher total soluble solids (TSS) and lower titratable acidity (TA), resulting in a sweeter flavor profile that may be preferred by consumers. Specifically, the ‘Pellecchiella’ exhibited a significantly higher polyphenol content, with catechin and epicatechin levels higher by 338% and 167%, respectively. The study further analyzed the variation in nutraceutical components in the puree and jam (carotenoids, total polyphenols, and antioxidant activity by ABTS, DPPH and FRAP), throughout the processing stages. Both cultivars showed a reduction in these parameters during the transformation process. For instance, the total polyphenol content exhibited a similar reduction of approximately 61% in both cultivars. However, the ‘Pellecchiella’ retained higher values in the jam, reflecting its naturally higher initial levels in the fresh fruit, and showed higher Redness Index. Overall, the results highlight ‘Pellecchiella’ as a cultivar having superior nutraceutical properties and good bioactive compound retention during processing, making it a valuable choice for both fresh consumption and processed products. These findings have significant implications for the functional food sector, as they underscore the importance of cultivar selection and processing strategies to preserve valuable bioactive compounds. By leveraging the natural advantages of local cultivars like ‘Pellecchiella’, producers could develop premium jams or puree-based functional products aimed at health-conscious consumers. Full article

Lilium brownii var. viridulum (Longya lily) is a widely used medicinal and culinary plant in China that is valued for its potential applications and development opportunities. The bulbs of Longya lily contain a variety of active components; volatile oil, as one of the main biologically active compounds, has been widely studied, and the stems, leaves, and flowers of Longya lily are also rich in volatile organic compounds (VOCs) and related pharmacological effects, but the horizontal comparison of different organs of lily plants is lacking. In order to promote the sustainable development of resources, the composition characteristics and differences of bulbs, stems, leaves, and flowers, as well as two crop management methods (bud-removal and non-bud-removal), were comprehensively studied by GC-IMS technology in this study. Additionally, multivariate statistical analyses were used to identify the key components responsible for the observed differences among the plant organs and treatments. The research identified a total of 93 volatile organic compounds in Longya lily samples, primarily consisting of aldehydes, alcohols, ketones, and esters. If the VOCs of Longya lily are to be used as raw materials, it is advisable to choose flowers and leaves with a higher concentration of these components for harvesting. Notably, bulbs that were non-bud-removal exhibited a greater total content of volatile flavor substances compared to those that were treated with bud removal, with hexanal-D and (E)-2-hexenal-D being the most prevalent volatile organic compounds. This study provided theoretical support for the harvesting parts and crop management methods of Longya lily based on volatile organic compounds and promoted the high-quality development of the Longya lily industry. Full article

Strong-flavor Baijiu, a widely popular distilled spirit in China, derives its characteristic aroma and quality largely from ethyl hexanoate, a key flavor compound. The concentration of ethyl hexanoate, influenced by its precursor hexanoic acid, is critical in defining the style and quality of this Baijiu variety. In this study, atmospheric and room temperature plasma (ARTP) mutagenesis technology was applied to strains isolated from Strong-flavor Daqu to enhance their acid and ester production capabilities. A hexanoic acid-producing strain, identified as Bacillus velezensis WY4 through morphological, physiological, biochemical, and molecular analyses, was used as the starting strain. Following 90 s of ARTP exposure, a mutant strain, WY4-3, was successfully developed, achieving a balance between high mutation diversity and moderate lethality. WY4-3 exhibited robust growth across a pH range of 4.2 to 5.0 and demonstrated high ethanol tolerance. After five days of fermentation, WY4-3 produced 0.36 g/L of total acid and 0.528 g/L of total ester, surpassing the wild-type strain. Enzymatic activity assays revealed significant enhancements in amylase (9.13%), saccharifying enzyme (101.72%), and esterification (573.71%) activities in WY4-3. Validation in multiple artificial esterification systems further confirmed the superior ester production capacity of this mutant strain. These findings enrich the microbial germplasm resources for Baijiu brewing and provide a solid foundation for strain selection and genetic improvement in Baijiu production processes. This study highlights the potential of ARTP mutagenesis in optimizing brewing microorganisms and improving the quality and consistency of Strong-flavor Baijiu. Full article

Tannins, a diverse class of polyphenolic compounds, are widely present in a variety of plant-based foods and beverages, where they contribute significantly to flavor, astringency, and numerous health benefits. Known for their antioxidant, anti-inflammatory, and cardioprotective properties, tannins are associated with a reduced risk of chronic diseases such as cardiovascular disease, cancer, and diabetes. Their bioavailability and metabolism are influenced by factors such as polymerization, solubility, and interactions with the gut microbiota. Tannin-rich beverages, including tea, wine, fruit juices, and cider, offer a range of health-promoting effects, including antioxidant, cardioprotective, and antimicrobial activities. In addition, tannins contribute significantly to the sensory and nutritional characteristics of fruits, nuts, and vegetables, influencing flavor, color, and nutrient absorption. The levels and efficacy of tannins are subject to variation due to factors such as ripeness and food processing methods, which can increase their impact on food quality and health. This review provides a comprehensive examination of the bioactive roles of tannins, their nutritional implications, and their sensory effects, highlighting their importance in both dietary applications and overall well-being. Full article

Nuts are widely recognized for their exceptional nutritional value, being rich in bioactive compounds such as polyphenols, mono- and polyunsaturated fatty acids, dietary fiber, and essential minerals. This review focuses on the effects of roasting technologies, specifically of pistachios, hazelnuts, and almonds, evaluating the changes in polyphenol contents, lipid profiles, and the release of volatile organic compounds through the Maillard reaction. Roasting, a common processing technique, enhances the sensory attributes of nuts, including flavor, aroma, and texture, while simultaneously influencing their nutritional and chemical profiles. The Maillard reaction, triggered during roasting, plays a crucial role in developing the characteristic flavors of roasted nuts, but can also lead to the formation of acrylamide under certain conditions. Understanding the balance between enhancing sensory quality and retaining nutritional properties is essential for optimizing roasting conditions. Innovative technologies offer sustainable and efficient alternatives to traditional methods. By focusing on these three major nut varieties, this review provides valuable insights into the changes that occur before and after roasting, highlighting strategies to balance sensory qualities and nutritional preservation. Further research is essential to refine these techniques, enabling the production of high-quality nuts that deliver superior health benefits while meeting consumer expectations. Full article

Capsicum annuum, commonly known as pepper, is a widely cultivated crop valued for its nutritional and economic significance. Among its varieties, the small red bell pepper, locally known as “pimienta palmera”, is a unique cultivar from La Palma in the Canary Islands, renowned for its distinctive flavor and use in traditional dishes. Despite its cultural importance, limited research exists on the chemical composition of this pepper variety. This study investigates the chemical constituents of dichloromethane and n-butanol fractions extracted from the pericarp of Capsicum annuum var. palmera. Isolation and structural elucidation of compounds were achieved using high-resolution mass spectrometry (HREIMS), nuclear magnetic resonance spectroscopy (NMR), and chromatographic techniques. A previously unreported pyrrolo-lactone compound, 2-(6-formyl-3-oxo-3,4-dihydro-1H-pyrrolo[2,1-c][1,4]oxazin-4-yl)acetic acid, was identified alongside other metabolites, including α-tocopherol, β-sitosterol, and oleic acid. This alkaloid adds to the chemical diversity of Capsicum species and highlights the unique bioactive potential of this regional pepper. These findings enhance the understanding of pimienta palmera’s composition and suggest potential applications in nutraceuticals and pharmacology due to the biological activity associated with pyrrole alkaloids. The characterization of this compound underscores the need to further explore the phytochemical richness of traditional crops with limited prior research. Full article

The bunching onion is an important leafy vegetable, prized for its distinctive flavor and color. It is consumed year-round in Japan, where a stable supply is essential. However, in recent years, the challenges posed by climate change and global warming have resulted in adverse effects on bunching onions, including stunted growth, discoloration, and the development of leaf tipburn, threatening both crop quality and yield. Furthermore, as bunching onion belongs to the Allium genus, which includes globally significant vegetables such as onion and garlic, studying the impact of climate change on bunching onion serves as an ideal model. The insights gained can also be applied to other crops and regions. This study investigates the effects of different summer growth conditions on the metabolite profile of heat-tolerant bunching onions with dark green leaf blade coloration and examines their association with leaf tipburn. Pigment compound quantification, functional component analysis, leaf tipburn rate assessment, and widely targeted metabolome profiling were performed across two commercial ${\mathrm{F}}_1$ varieties, one purebred variety, and six Yamaguchi Prefecture-bred ${\mathrm{F}}_1$ lines under different growing conditions. The results obtained were subjected to comparative analyses based on the varieties and groups classified by high and low leaf tipburn rates. The results revealed that $\beta$-carotene accumulation peaked with May sowing and July harvest, while the highest accumulation of other pigment compounds was observed with May sowing and September harvest. Additionally, metabolome analysis related to leaf tipburn rates identified several organosulfur compounds, with gamma-glutamyl-propenyl cysteine sulfoxide emerging as one of the key compounds. Based on the intensity data, the fold change of this metabolite was calculated to be 1.66, indicating an increase in the leaf tipburn group compared to the control group. In the control groups, organosulfur compounds appeared to undergo turnover in preparation for stress response. In contrast, in the leaf tipburn groups, it is hypothesized that organosulfur compounds were converted into precursors of pungency, resulting in inadequate responses to stress. This study aims to elucidate the mechanisms through which organosulfur compounds transition into pungent compounds and to develop varieties with improved resistance to leaf tipburn. Full article

Matcha is a very popular tea food around the world, being widely used in the food, beverage, health food, and cosmetic industries, among others. At present, matcha shade covering methods, matcha superfine powder processing technology, and digital evaluations of matcha flavor quality are receiving research attention. However, research on the differences in flavor and quality characteristics of matcha from the same tea tree variety from different typical regions in China is relatively weak and urgently required. Taking Japan Shizuoka matcha (R) as a reference, the differences in sensory quality characteristics and non-volatile substances of matcha processed with the same tea variety from different regions in China were analyzed. The samples were China Hangzhou matcha (Z1), China Wuyi matcha (Z2), China Enshi matcha (H), and China Tongren matcha (G), which represent the typical matcha of eastern, central, and western China. A total of 1131 differential metabolites were identified in the matcha samples, comprising 118 flavonoids, 14 tannins, 365 organic acids, 42 phenolic acids, 22 alkaloids, 39 saccharides, 208 amino acids and derivatives, 17 lignans and coumarins, seven quinones, 44 nucleotides and derivatives, 14 glycerophospholipids, two glycolipids, 15 alcohols and amines, 140 benzenes and substituted derivatives, 38 terpenoids, 30 heterocyclic compounds, and 15 lipids. Kaempferol-7-O-rhamnoside, 3,7-Di-O-methylquercetin, epigallocatechin gallate, epicatechin gallate, and epigallocatechin were detected in Z1, Z2, H, and G. A total of 1243 metabolites differed among Z1, Z2, and R. A total of 1617 metabolites differed among G, H, and R. The content of non-volatile difference metabolites of Z2 was higher than that of Z1. The content of non-volatile difference metabolites of G was higher than that of H. The 20 key differential non-volatile metabolites of Z1, Z2, G, and H were screened out separately. The types of non-volatile flavor differential metabolites of G and H were more numerous than those of Z1 and Z2. The metabolic pathways, biosynthesis of secondary metabolites, biosynthesis of co-factors, flavonoid biosynthesis, biosynthesis of amino acids, biosynthesis of various plant secondary metabolites, and purine metabolism of metabolic pathways were the main KEGG pathways. This study provides new insights into the differences in metabolite profiles among typical Chinese matcha geographic regions with the same tea variety. Full article

Food preservation techniques changed during the industrial revolution, as safer techniques were developed and democratized. However, one of the simplest techniques, adding salt, is still employed in a wide variety of products, not only as a flavor enhancer but as a method to allow for the controlled fermentation of products such as fruits. The objective of the present study consists of evaluating the quality of different salt-reduced fermented fruits through the application of the lactic acid bacteria (LAB) Lacticaseibacillus paracasei and vacuum, as well as assessing the LAB as a preventive measure against Escherichia coli O157:H7. To achieve this goal, microbial plate count techniques, the evaluation of the physicochemical characteristics, and Check-All-That-Apply/Rate-All-That-Apply sensory analyses were performed on bananas and apples individually fermented at 30 °C for 2 and 7 days, respectively. Additionally, a challenge test using E. coli as pathogenic bacteria was performed. The characteristics of each fruit determined the efficiency of the LAB’s protective activity. LAB-inoculated batches controlled the growth of E. coli in both salted fruits, but this pathogenic bacterium in the apple case was controlled even in the salt-reduced batch. Sensorially, only inoculated fermented apples found a reduction in off-flavor and old fruit smell; however, higher acceptability was found in the salt-reduced with LAB batches of both fruits. Thus, Lacticaseibacillus paracasei proved to be a cheap, easy, and feasible protective method that can ensure a protective strategy on salt-reduced fermented apples and should be studied particularly for different fruits. Full article