Fruity Flavor Research Articles

Understanding consumer acceptability of verjuice, its potential applications and sensory and chemical drivers of liking

The wine sector is working to add value, enhance sustainability and reduce waste, yet often creating new products with unknown consumer acceptance. Verjuice, juice made from discarded unripe thinned grapes, is an example. Whilst verjuice has various culinary uses, its versatility in beverages continues to expand. However, its sensory drivers of liking when consumed as a drink, and their potential impact on its application remain unclear. Chemical drivers of sensory characteristics are also unknown representing a critical knowledge gap needed to guide product innovation. This study aimed to provide new knowledge regarding consumer acceptability of verjuice by identifying its sensory drivers of liking as a beverage, evaluating its potential use in different applications and identifying chemical drivers of its sensory characteristics. New Zealand consumers (n = 93) evaluated 13 verjuice samples from different countries. Furthermore, verjuice familiarity and its influence on emotional response was investigated to determine likely future consumer engagement. Sweetness was the most positive driver of liking in verjuice overall, followed by fruity and floral notes, smoothness, and to a lesser extent citrus flavour. Consumers expressed varied preferences for verjuice’s sensory profile, with fruity, floral, and honey flavours driving beverage application, whilst winey and green apple notes were more associated with culinary scenarios. Some association between chemical parameters and sensory attributes were evident (e.g. sugars were highly associated with perceived sweetness, fruity, and floral attributes; these attributes also shared proximity with 1-hexanol and cyclohexanol). The general idea of verjuice elicited positive valence emotions, but consumers who were ‘not familiar’ felt more curious, and those ‘familiar’ felt happier and more satisfied. Findings highlight the potential to tailor verjuice for specific applications by understanding desired sensory profiles and related chemical parameters. Recognising the interplay between familiarity level and emotional response is crucial for positioning the product in the marketplace and fostering consumer engagement. Marketing initiatives are needed to increase verjuice familiarity and support product innovation, leading to increased product appeal.

Sensory characteristics of powdered-fiber drinks using CATA (check-all-that-apply) method

Dietary fiber is crucial in the human diet. This nutrient has been reported to be able to prevent overweight and obesity by improving satiety levels. However, the intake of fiber remains low, and the use of fiber supplementation is recommended. Dietary fiber in the form of powdered drinks has been recently launched and become popular in the market with different types, flavors and brands. The objective of this study was to evaluate the sensory characteristics of powdered fiber drink products. Six commercial powdered fiber drink samples were selected representing the powdered fiber drink products that are available in the Indonesian market. The sensory characteristic was evaluated using CATA (Check-All-That-Apply) method by 121 consumers (mean age 20.3 ± 3.2-year-old). In addition, consumer acceptability was also measured. The results indicated that the fiber drink samples have different characteristics due to the different flavors. Fruity flavors such as berries, passion fruits, and citrus were preferred as compared to vegetable flavors, and this was significant for aroma liking (p=0.017). Interestingly, the addition of bird nests in the ingredient of the fiber drink did not influence the liking nor the sensory characteristics of the samples. This study can be used to develop a powdered fiber drink product with good acceptability by considering the sensory characteristics.

Analysis of Aroma Components of Enzymatic Hydrolysis Products of Oak Lignin from Different Producing Areas

The morphology and structure of lignin in French oak, American oak and Chinese Mongolian oak were observed and compared by scanning electron microscopy (SEM). The results showed that the surface of lignin after enzymatic hydrolysis was more irregular and the contact area was obviously increased. GC-MS detected 3 kinds of lignin, 4 kinds of components and 30 kinds of volatile substances. The lignin content of French oak was the highest (8911.5 ± 512.2 μg/L, 29 kinds), followed by that of American oak (8071.7 ±541.9 μg/L, 26 kinds), and that of Mongolian oak was the least (7903.3 ± 492.5 μg/L, 26 kinds). The results of aroma characteristics analysis, principal component analysis and heat map analysis showed that the aroma components of the three kinds of oak lignin were significantly different. French oak lignin could provide more volatile phenols, with obvious smoky, woody and sweet flavor. Mongolian oak lignin carries more phenolic and ester compounds, providing a relatively soft floral, fruity flavor. American oak lignin has a relatively average aroma substance content, which can bring strong and complex complex aroma characteristics.

Effect of roselle and purple rice powder on baking quality and aroma characteristic of bread

The effects of different dosages of roselle flour (0 %, 4 %, and 8 %) and purple rice flour (5 %, 10 %, and 15 %) on the properties of the dough, the quality of the bread, the phenolic compounds contained, the anthocyanin content and the aroma profile were investigated by adding roselle flour and purple rice flour to the wheat flour. The results showed that the addition of purple rice flour elevated the G′ and G″ of the dough and improved the viscoelasticity of the bread. The addition of roselle flour disrupted the gluten network structure in the bread, resulting in an increase in chewiness and hardness, but within acceptable limits. The color of the bread also changed significantly. In addition, increased polyphenol content in the bread, roselle flour, and purple rice flour significantly (p < 0.05) increased the aroma profile of bread, giving it a richer odor. In particular, the presence of more acids, alkanes and heterocyclic compounds associated with fruity flavors also adds a distinctive burnt and ‘roasted’ note. Therefore, the addition of moderate amounts of roselle flour and purple rice flour was beneficial in improving the baking quality of bread, especially positively affecting the flavor.

Decoding the Effect of Running on Flavor Perception Changes during Consumption of Sports Drinks.

An online survey was conducted to show that most respondents preferred sports drinks with sweet and fruity characteristics. Eleven sports drinks with higher consumers' preferences were further selected for aroma and taste evaluation. Temporal dominance of sensations analysis showed that fruity and fresh attributes were dominant, while sour and fruity sweet were dominant tastes during consumption. β-Damascenone, β-ionone, and linalool contributing to floral perception, γ-decalactone, ethyl cinnamate, and isoamyl acetate contributing to fruity perception, and menthol contributing to fresh perception were confirmed by odor activity value analysis. Running affected the nasal air flow and the saliva secretion, resulting in the flavor perception changing from fruity sweet, sweet, and fruity to sour because the recognition threshold decreased for sweet, fruity, floral, and fresh flavors and increased for saltiness, astringency, and sour tastes.

Synthesis of Isoamyl Fatty Acid Ester, a Flavor Compound, by Immobilized Rhodococcus Cutinase.

Isoamyl fatty acid esters (IAFEs) are widely used as fruity flavor compounds in the food industry. In this study, various IAFEs were synthesized from isoamyl alcohol and various fatty acids using a cutinase enzyme (Rcut) derived from Rhodococcus bacteria. Rcut was immobilized on methacrylate divinylbenzene beads and used to synthesize isoamyl acetate, butyrate, hexanoate, octanoate, and decanoate. Among them, Rcut synthesized isoamyl butyrate (IAB) most efficiently. Docking model studies showed that butyric acid was the most suitable substrate in terms of binding energy and distance from the active site serine (Ser114) γ-oxygen. Up to 250 mM of IAB was synthesized by adjusting reaction conditions such as substrate concentration, reaction temperature, and reaction time. When the enzyme reaction was performed by reusing the immobilized enzyme, the enzyme activity was maintained at least six times. These results demonstrate that the immobilized Rcut enzyme can be used in the food industry to synthesize a variety of fruity flavor compounds, including IAB.

Analysis of tea quality of large-leaf black tea with different harvesting tenderness based on metabolomics

The harvesting tenderness of tea fresh leaves has a significant effect on the flavor and aroma quality of black tea (BT), which is one of the important standards for BT grading. In this study, sensory evaluation, electronic tongue technique and metabolomics were performed to evaluate the flavor and aroma qualities of three different tenderness of large-leaf BTs that were manufactured from the fresh leaves of single-bud, one-bud and one-bud two-leaf teas, respectively. The results of the electronic tongue and sensory evaluation indicated that the increase in the tenderness of the fresh leaf material enhanced the sweetness, freshness and fruity flavor of the tea and reduced the bitterness of the tea. A total of 519 differential flavor components and 84 differential aroma components were identified by metabolomics. Among them, elevated levels of maltitol, cyclic leucine and l-methionine and l-aspartic acid led to elevated sweetness and freshness in more tender tea leaves. Reduced levels of 4-aminosalicylic acid, tyrosol, uracil, inosine, benzamide, and l-tyrosine led to reduced bitterness in BT. Moreover, the content of volatiles such as (Z)-2-Decenal, Phenylacetic acid propyl ester, Acetophenone, and 2-phenylethyl ester were increased, which contributed to the fruity aroma in the high-tenderness tea. This study provides a theoretical basis for grading the flavor quality of BT with different tenderness.

Changes in volatile compounds in withering tea leaves after infestation with tea green leafhopper (Empoasca onukii Matsuda)

The effects of withering, cultivar yellowing, and Empoasca onukii infestation on tea leaf aroma have each been characterized, but variations in volatile compound (VC) contents as a result of co-occurrence of these factors remain unclear. In the present study, we analyzed VC contents in E. onukii-damaged leaves of Camellia sinensis (L.) cv. ‘Yinghong No. 9’ and the yellow bud variant ‘Yellowish Yinghong No. 9’ during the withering process. We found that glycoside-derived volatiles (GDVs) were the most abundant type of VCs, accounting for more than 83% of the total VC content. Linalool formed the main body of the tea aroma, contributing a floral, fruity scent. Differential accumulation of octanal and geranyl acetone in fresh leaves corresponded to differences in the aroma profiles between Yellowish Yinghong No. 9 and Yinghong No. 9. A higher degree of withering did not alter the pleasant aroma odors of Yellowish Yinghong No. 9, but rather maintained the floral, fruity flavors and reduced greenish odors and levels of defense-related compounds (e.g., benzeneacetaldehyde, benzyl nitrile) induced by E. onukii infestation. This study clearly establishes the effects of withering on the aroma profiles of E. onukii-infested leaves in both a standard and a yellow bud mutant tea variety, suggesting a method of maintaining the economic value of even insect-damaged tea leaves.

Profiling flavor characteristics of cold brew coffee with GC-MS, electronic nose and tongue: effect of roasting degrees and freeze-drying.

Roasting is an important process in the formation of coffee flavor characteristics, which determines the quality of coffee and consumer acceptance. However, the influence of roasting degree on the flavor characteristics of cold brew coffee has not been fully described. In the present study, the flavor characteristics of cold brew coffee with different roasting degrees were compared in detail by using chromatographic and electronic sensory approaches, and the flavor changes induced by freeze-drying were investigated. Pyrazine and heterocyclic compounds were the main aroma compounds in coffee, and gradually dominated with the increase of roasting. Pyridine was consistently present in cold brew coffees of different roasting degrees and showed significant gradient of quantity accumulation. Aroma compounds such as pyrazine, linalool and furfuryl acetate were the main contributors to coffee roasting, floral and fruity flavor. Freeze-drying preserved the fruity and floral aromas of medium-roasted cold brew coffee, whereas reducing the bitterness, astringency and acidity properties that are off-putting to consumers. The higher consumer acceptance and enjoyment in medium roast cold brew coffee may be related to its stronger floral and fruity aroma. The aroma profile qualities of freeze-drying processed medium roasted cold brewed coffee were more dominant and more suitable for freeze-drying processing than medium dark roasting. Application of freeze-drying for cold brew coffee will promote the convenience of drinking. The present study provides valuable technical guidance in improving the flavor and quality of cold brew coffee, and also promotes its commercialization process. © 2024 Society of Chemical Industry.

Valorisation Process Using Lactic Acid Bacteria Fermentation Induces Significant Changes in the Physical and Functional Properties of Brewers Spent Yeast

Brewer’s spent yeast (BSY) is a plentiful by-product of the brewing process. Currently regarded as a waste product, this low-value material is used in animal feed formulations or disposed of. However, BSY is known to be nutritionally dense, particularly regarding high-quality proteins, fibre, vitamins, and minerals. Previous work has examined the effect of a process including fermentation with Lactobacillus amylovorus FST 2.11 on BSY and indicates a reduction in bitterness intensity and an increase in sour and fruity flavours. The current study expands on this previous work, examining the changes in composition and functionality resulting from this upcycling process. The major changes include protein degradation and a decrease in pH, leading to increased protein solubility by 41%, increased foam stability by up to 69% at pH 7, and improved emulsion stabilising characteristics as well as differences in rheological behaviour during heating. Compositional changes are also detailed, with evidence of glucan and trehalose degradation. These changes in the physical and functional properties of BSY provide useful information, particularly with regard to the incorporation of BSY into food products for human consumption.

Increasing Dimethylsulfide and Polyfunctional Thiols, an Opportunity to Enhance the Fruity Flavors of NABLABs

At present, non-alcoholic beers and low-alcoholic beers (NABLABs) suffer from premature oxidation when fresh, and from a lack of fruity fermentation aromas. In wines, dimethylsulfide (DMS) is known to enhance truffle nuances and the fruity character. This offers an opportunity to improve the flavor of NABLABs. In this work, levels of free DMS and its potential precursors (S-methylmethionine/SMM and dimethylsulfoxide/DMSO) were assessed in eleven commercial NABLABs, in parallel with their amounts of fruity esters and polyfunctional thiols. Except in two dry-hopped samples and a fruity beer, free DMS was detected at very low levels in all fresh NABLABs (four samples even displayed no detectable GC peak), likely because of dealcoholization or too-short fermentation. Through NABLABs aging, the free DMS concentration increased (+63% on average after two years), at a degree correlated with the initial SMM level (2–118 µg/L DMS eq.; R2 = 0.79). This SMM amount revealed to be also correlated with the group I amino acid residual content (more consumed through traditional fermentations). Unlike DMSO, SMM showed significant release of free DMS after aging in spiking experiments (4% degradation after 30 days at 20 °C). As fruity fermentation esters are found in NABLABs at much lower concentrations than in conventional lagers, increasing both DMS and polyfunctional thiols by dry hopping (or DMS-enriched extracts) emerges as an opportunity to improve them.

Analysis of forage quality, volatile organic compounds and metabolic pathways in alfalfa (Medicago sativa L.) at different stages based on electronic nose and GC-MS

The odor of alfalfa (Medicago sativa L.), the most extensively cultivated forage, can interfere with livestock feeding. This study used an electronic nose in conjunction with gas chromatography–mass spectrometry (GC–MS) to examine the quality, volatile organic compounds (VOCs), and metabolic pathways of alfalfa at budding (X), early flowering (C), and full flowering (S) stages. Results showed that terpenoids increased first and then decreased with growth and development, heterocyclic substances decreased continuously, and alcohols and ketones increased. The crude protein and ether extract decreased and were positively correlated with terpenoids, heterocycles, and nitrogen and sulfur compounds, while the dry matter content, soluble carbohydrates, and neutral detergent fiber increased and were positively correlated with alcohols and ketones. The VOCs were most accumulated in the early flowering stages, which had more sweet and fruity flavors, and the main substances that differed from the budding stage and the full flowering stage were methyl heptanoate, butyl butyrate, β-ionone, and other esters and terpenoids. The monoterpene, sesquiterpene, and triterpene pathways were up-regulated in the early flowering stage, and the phenyl-propylene synthesis pathway was up-regulated in the full flowering stage. These substances and pathways were key to further improving alfalfa odor, grade and utilization.Graphical

Waste to Wealth: Dynamics and metabolic profiles of the conversion of jackfruit flake into value-added products by different fermentation methods

Thus far, little is known about whether jackfruit flake, a byproduct of jackfruit, can be used as a fermentation substrate to obtain value-added products through microbial fermentation. Here, jackfruit flake puree was fermented by three different ways: spontaneous fermentation (JF), inoculated with LAB (JFL), inoculated co-fermentation with LAB and yeast (JFC). In contrast to JF, the total polyphenol and flavonoid content and syndrome-associated enzyme inhibition are significantly increased in JFC at the end of fermentation. Electronic tongue analysis revealed that the JFC was significantly lower in astringency and higher in bitterness. 41 volatile compounds were identified during fermentation by HS-SPME-GC–MS, and JFC was richer in honey, rose, and fruity flavors. A total of 290 compounds were screened for discriminative pre- and post-fermentation differential metabolites by non-target metabolomics analysis. These results provide a potential reference for the conversion of jackfruit waste into functional products using fermentation.

Phyllosphere to Ferment: Site Conditions Structure Cacao Pod and Fermentation Microbiomes in Hawaiʻi

Microbial fermentation is crucial to the development of flavors in cacao-based products, but how the abiotic environment and pod surface microbiomes can contribute to these different sensory profiles is underdeveloped. To better understand the connections between environment, plant variety, associated pod phyllosphere microbiomes, and the fermentation microbiome, we characterized the fungi and bacteria on pod surfaces and early fermentations of two cacao varieties across wet and dry sites on the island of O‘ahu, Hawai‘i. We showed that site (and the environmental conditions linked to those sites) significantly influenced the microbiomes of both the pod phyllosphere and fermentations but did not significantly explain the differences between cacao varieties. Certain taxa of bacteria and fungi seemingly prefer the wet Kualoa Ranch site compared with the drier Urban Garden Center Site. Rare members of the pod phyllosphere communities became highly enriched during fermentation, where basidiomycetous yeasts ( Filobasidium sp., Hannaella zeae, Rhodotorula mucilaginosa, R. paludigena, and Sporobolomyces carnicolor) became dominant at the wet site, and both ascomycetous and basidiomycetous yeasts ( Hyphopichia burtonii, Meyerozyma sp., Yamadazyma phyllophila, Filobasidium sp., Kwoniella heveanensis, R. mucilaginosa, Sporobolomyces sp., and S. carnicolor) became dominant at the dry site. The agricultural production site where cacao plants are grown should be considered carefully because it is likely important in structuring microbes that are present on pod surfaces and the microbes (mostly yeasts) that will be carried forward into fermentation. These yeasts may contribute to the development of the unique fruity or floral flavors in chocolates produced in Hawai‘i. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Lactic Acid Fermentation as a Valorising Agent for Brewer’s Spent Yeast—Improving the Sensory Quality and Nutritional Potential

Brewer’s spent yeast (BSY) is one of the brewing industry’s most plentiful side-streams. Abundant, low-cost and high in nutrients, it has great potential for application in food technology and human nutrition. With the ever-increasing interest in sustainability, waste reduction and circular food systems, the use of BSY as a novel food ingredient may be the route to add exponential value while reducing the environmental impact. However, negative flavour characteristics and high amounts of alcohol severely limit the current applications of BSY. This study explores the use of processing involving lactic acid bacteria (LAB) fermentation technology as a means of improving BSY quality characteristics and examines the effects of this process on the chemical, nutritional and sensory characteristics of BSY. The results reveal that BSY is a suitable substrate for LAB fermentation, successfully supporting the growth of Lactobacillus amylovorus FST 2.11. Compared to the unfermented BSY (CBSY), fermentation significantly reduced the perceptible bitterness of the BSY as detected by a sensory panel, from 6.0 ± 2.8 units to 0.9 ± 0.7 units, respectively. Fermented BSY (PBSY) had enhanced sour and fruity flavours, and a variety of other volatile compounds and metabolites were determined. Protein profiles showed significant protein degradation, and free amino acid levels were greatly increased following fermentation, from 2.8 ± 0.2 g/100 g to 10.5 ± 0.4 g/100 g, respectively. Protein quality was high, with the CBSY and PBSY providing well over the required level (&gt;100%) of essential amino acids per gram protein, with the exception of sulphur amino acids (98%). Major physical differences were observed using scanning electron microscopy. This study concludes that LAB fermentation positively affects the sensory and nutritional characteristics of BSY and can aid in the incorporation of brewer’s spent yeast into foods for human consumption.

An ingredient co-occurrence network gives insight into e-liquid flavor complexity.

Part of the appeal of e-cigarettes lies in their available flavors. To achieve attractive flavors, e-liquids contain many different flavoring agents, which allow many flavoring combinations. To advance our knowledge of e-liquid flavors and compositions and to evaluate the effect of legislation, we determined whether there are ingredient combinations that are frequently used together. We used e-cigarette ingredient data from the European Common Entry Gate system (EU-CEG) as available on 31 December 2022. In e-liquids, we found 214 ingredient pairs with a co-occurrence odds ratio greater than 10. Together, these consisted of 62 unique ingredients. Network analysis revealed that ingredients were grouped together based on their flavor and/or chemical structure. We identified two densely connected regions (clusters) in the network. One consisted of six ingredients with sweet-vanilla-creamy flavors. The second cluster consisted of 13 ingredients. While some of these have fruity flavors, others, such as alkyl carboxylic acids and dimethyl sulfide, are known to have unpleasant flavors. Additional data and literature analyses indicated that alkyl carboxylic acids can contribute to a creamy and sweet-fruity taste, whereas dimethyl sulfide can contribute to a more refined fruity taste. These results exemplify that the flavor of e-liquids is not just the sum of its parts. Big data analyses on product data can be used to detect such patterns, but expert knowledge and additional data are needed for further interpretation. Monitoring of e-liquid flavors as well as ingredients will remain important to regulate e-liquid product attractiveness.

Exploring jujube wine flavor and fermentation mechanisms by HS-SPME-GC–MS and UHPLC-MS metabolomics

The fermentation metabolites significantly influence the quality of jujube wine. However, the dynamics of these metabolites during fermentation are not well understood. In this study, a total of 107 volatile and 1758 non-volatile compounds were identified using a flavor-directed research strategy and non-targeted metabolomics. The increase in esters and alcohols during fermentation shifted the aroma from grassy, mushroomy, and earthy to a floral and fruity flavor in the jujube wine. Leucine and phenylalanine were notably enriched during fermentation, potentially benefiting human health and enriching the flavor of fruit wines. Moreover, pathway analysis identified four key metabolic pathways and two crucial metabolic substrates, pyruvate and l-aspartate. This study provides a theoretical reference for optimizing the fermentation process and enhancing the quality of jujube wine.

Assessment of the Physicochemical, Antioxidant, Microbial, and Sensory Attributes of Yogurt-Style Products Enriched with Probiotic-Fermented Aronia melanocarpa Berry Juice.

The aim() of this study was to create() various formulations of yogurt enriched with freeze()-dried adjuncts, namely() (i) probiotic Lactobacillus plantarum ATCC 14917 culture(), and (ii) L. plantarum ATCC 14917 fermented black chokeberry juice, along with a commercial() starter culture(). The goal was to enhance() functionality and optimize the nutritional() value() of the products. These new yogurt-style() formulations were subsequently() compared with commercially produced yogurt. All products demonstrated() favorable() physicochemical properties, and the probiotic strain() consistently() maintained viable() levels exceeding 7 log() cfu/g throughout() the entire() storage() period(). The fermented milk produced with the adjunct-free L. plantarum cells, as well as the yogurt produced with the proposed() lactobacilli-fermented chokeberry juice, exhibited the highest lactic acid() production() (1.44 g/100 g yogurt by the end of storage()). Levels of syneresis were observed at lower() values() in yogurt produced with freeze()-dried fermented chokeberry juice. Yogurts prepared() with the lactobacilli-fermented freeze()-dried chokeberry juice displayed elevated total() phenolic content() and antioxidant capacity() (25.74 µg GAE/g and 69.05 µmol TE/100 g, respectively()). Furthermore, sensory tests revealed a distinctive() fruity flavor() in samples incorporating fermented juice. The results demonstrate() that probiotic L. plantarum-fermented chokeberry juice enhances() both the antioxidant capacity() and the viability of beneficial() bacteria() in yogurt while it can be readily() applied and commercialized, especially in the form of a freeze()-dried formulation.

Effects of mutant yeast strain and distillation method on sensory characteristics and volatile compounds in Korean distilled spirit, soju

The effects of mutant yeast and distillation method on volatile compounds and sensory characteristics of the Korean distilled soju were investigated. Saccharomyces cerevisiae 88–4 and its 5,5,5-trifluoro-dl-leucine (TFL)-resistant mutant GNIA2 were used for brewing and distilling under atmospheric and vacuum conditions for manufacturing soju. The volatiles in the soju were comparatively analyzed by semi-quantification using solid-phase microextraction-gas chromatography/mass spectrometry. The mutant strain led to an increase in 9 volatiles and a decrease in 4 volatiles in distilled soju. Considering the threshold, ethyl caproate, ethyl caprylate, ethyl caprate, isoamyl caprylate, ethyl laurate, isoamyl acetate, and isoamyl alcohol might contribute to the enhanced fruity, floral, and sweet flavors in distilled soju. Meanwhile, higher alcohols and esters were 15% and 250% higher in atmospheric distillation than in vacuum distillation. The difference in flavor component, especially, esters content may contribute to the flavor of soju distilled at atmospheric pressure. Comparing the effects of yeast and distillation method on volatile contents, yeast had a greater effect on higher alcohol content, while distillation method had a greater effect on ester content. These results showed that the quality of soju can be diversified by combining mutant yeast with appropriate distillation methods.

Effects of lactic acid bacteria on antioxidant activity in vitro and aroma component of Eucommia ulmoides tea.

Eucommia ulmoides tea is a popular functional health drink in Asian countries, but its unique herbal aroma is difficult for consumers to accept. The effects of four lactic acid bacteria strains (Lactobacillus plantarium, Lactobacillus bulgaricus, Lactobacillus acidophilus and Streptococcus thermophilus) fermentation on the physicochemical property, antioxidant activity in vitro and aroma component of E. ulmoides leaves were studied. Within the four strains, the sample by L. bulgaricus fermentation showed the higher concentrations of chlorogenic acid, geniposidic acid and stronger antioxidant activity in vitro. Moreover, the sample by L. bulgaricus fermentation produced a stronger fruity and floral flavor. These results suggested that L. bulgaricus was the best strain for fermentation E. ulmoides tea. The differences between different strains should be considered when selecting lactic acid bacteria for raw material fermentation of fruits and vegetables.