Sensory Characteristics and Volatile Compounds of Herbal Teas and Mixtures of Bush Tea with Other Selected Herbal Teas of South Africa

Gowda SG, M. Gangadhara R, Gowda D, Hui SP. Exploration of New Lipid Nutrients and Their Characterization in Herbal Teas Using Non-Targeted Liquid Chromatography-Mass Spectrometry

Herbal teas are blends of leaves, seeds, fruits, and flowers from various plants that provide relaxation, anti-inflammatory benefits, and immune system support for conditions such as diabetes and asthma. Despite their health benefits, comprehensive lipidomic data on herbal teas are limited in the literature. We used non-targeted liquid chromatography-linear ion trap orbitrap mass spectrometry to identify and correlate the lipid species in the following six herbal tea samples: fennel, ginger, juniper, lemon peel, orange peel, and rosehip. A total of 204 lipid molecular species were identified, and multivariate analysis revealed a significant difference between lipid species in herbal teas. Saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs) are significantly abundant in juniper, including ω-3 and ω-6 fatty acids, followed by fennel. Cluster correlations showed that ginger contained mainly sphingolipids and lysophospholipids, whereas fennel was rich in phospholipids. No significant variations in the content of triacylglycerols were observed in any of the herbal teas analyzed. The ratio of PUFAs to SFAs in herbal teas showed that orange peel had the highest ratio, followed by lemon peel and fennel, indicating their potential health benefits. In addition, using high-resolution mass spectrometry, various lipids such as fatty acid esters of hydroxy fatty acids and N-acyl-lysophosphatidylethanolamines were identified and characterized in these herbal teas. This study provides a comprehensive lipid analysis and detailed characterization of lipids in six herbal teas, highlighting their plausible applications in the field of nutrition and various food industries for the development of functional foods.

Identification of phenolic compounds from fermented Moringa oleifera Lam. leaf supplemented with Fuzhuan brick tea and their volatile composition and anti-obesity activity

As a nutritious plant with valuable potential, the Moringa oleifera Lam. (MOL) leaf addition on Fuzhuan brick tea (FBT) for the co-fermentation (MOL-FBT) was an industry innovation and a new route to make full use of MOL leaf. After optimization of the extraction conditions, the best conditions for the polyphenols extraction method from MOL-FBT (MFP) were 60°C for 40 min (1:80, V/W) using response surface methodology. A total of 30 phenolics were identified and quantified. Most of the polyphenols were increased after adding MOL leaf for co-fermentation compared to FBT polyphenols. In particular, caffeic acids were found only in MFP. Moreover, the MFP received high value in taste, aroma, and color. In total, 62 volatile flavor compounds, consisting of 3 acids, 5 alcohols, 15 aldehydes, 4 esters, 20 hydrocarbons, 10 ketones, and 5 others, were identified in MFP. In addition, MFP inhibited 3T3-L1 preadipocyte differentiation in a dose-dependent manner and decreased lipid accumulation via the peroxisome proliferator-activated receptor gamma (PPARγ)/CCAAT/enhancer binding protein alpha (CEBPα)/cluster of differentiation 36 (CD36) axis and induced a brown adipocyte-like phenotype. In vivo experiments were further conducted to confirm the in vitro results. MFP regulated lipid accumulation, glucose/insulin tolerance, improved liver and kidney function, and inhibited the secretion of pro-inflammatory factors by the PPARγ/CEBPα/CD36 axis and alleviated inflammation in high fat and high fructose diet-induced obese mice. In summary, MFP possesses high-quality properties and anti-obesity effects, as well as the great potential to be used as a novel functional food product.

Uncovering the effect of Moringa oleifera Lam. leaf addition to Fuzhuan Brick Tea on sensory properties, volatile profiles and anti-obesity activity

As a nutritious plant with valuable potential, the Moringa oleifera Lam. leaf addition to Fuzhuan Brick Tea (FBT) for co-fermentation is an industrial innovation and a new route to make full use of Moringa oleifera Lam. leaves. However, the sensory properties, volatile profiles and anti-obesity activity of Fuzhuan Brick (Moringa oleifera Lam.) tea (MFBT) are still unknown. The results demonstrated that MFBT has richer and more complex smell and taste, better color and higher overall acceptance scores. In total, 57 volatile flavor compounds, consisting of 3 acids, 16 hydrocarbons, 5 esters, 8 ketones, 13 aldehydes, 6 alcohols and others, were identified using HS-SPME-GC-MS. The characteristic odor components in MFBT were 3-buten-2-one, 4-(2,6,6-trimethyl-1-cyclohexen-1-yl)- and 1-cyclohexene-1-carboxaldehyde, 2,6,6-trimethyl-, which gave it a floral, woody, sweet, herbal and fruity aroma. 2-Octenal, (E) contributed significantly to the aroma of FBT, which could impart fresh, fatty and green aromas. In addition, MFBT could better regulate lipid accumulation, glucose tolerance, insulin tolerance and inflammation response more effectively than FBT. The mechanism is that MFBT could better regulate the dysbiosis of gut microbiota induced by HFFD, mainly increasing the abundance of beneficial bacteria such as SCFA-producing bacteria (Bacteroidetes, Lactobacillaceae, Bacteroidales_S24-7_group and Clostridiaceae_1) and decreasing the abundance of harmful bacteria such as pro-inflammatory/obesity and metabolic syndrome-related bacteria (Proteobacteria, Deferribacteres, Desulfovibrio, Catenibacterium and Helicobacter), which in turn increased feces short-chain fatty acids and lowered circulating lipopolysaccharides. These results suggested that co-fermentation with Moringa oleifera Lam. leaf could significantly improve the quality and enhance the anti-obesity effect of FBT.

Eco-physiological response of secondary metabolites of teas: Review of quality attributes of herbal tea

Herbal tea is a rich source of secondary metabolites which are reputed to have medicinal and nutritional efficacy. These secondary metabolites are influenced by the abiotic and biotic stresses that improve the production of herbal teas in terms of biomass production, accumulation and partitioning of assimilates of compounds. In this study, various examples of herbal teas have been shown to respond differently to secondary metabolites affected by environmental factors. Thus, the meta-analysis of this study confirms that different herbal teas' response to environmental factors depends on the type of species, cultivar, and the degree of shade that the plant is exposed. It is also evident that the metabolic processes are also known to optimize the production of secondary metabolites which can thus be achieved by manipulating agronomic practices on herbal teas. The different phenolic compound in herbal teas possesses the antioxidant, antimicrobial, antiatherosclerosis, anti-inflammatory, antimutagenic, antitumor, antidiabetic and antiviral activities that are important in managing chronic diseases associated with lifestyle. It can be precluded that more studies should be conducted to establish interactive responses of biotic and abiotic environmental factors on quality attributes of herbal teas.

In Vitro Alpha-Amylase Enzyme Assay of Hydroalcoholic Polyherbal Extract: Proof of Concept for the Development of Polyherbal Teabag Formulation for the Treatment of Diabetes

For the treatment and maintenance of postprandial blood glucose increases (i.e., diabetes mellitus), alpha (α)-amylase is a well-known therapeutic target. In this paper, we report an initial exploration of the work, i.e., in vitro alpha-amylase activity of the hydroalcoholic polyherbal extract of the selected plants. After drying, the plant material is ground individually, and at least 100 gm of the crude powder is prepared from each plant. 100 gm of each plant was combined, and a total of 500 gm of the crude powder (Ichnocarpus frutescens (100 gm) + Ficus dalhousie (100 gm) + Crateva magna (100 gm) + Alpinia galangal (100 gm) + Swertia chirata (100 gm)) was prepared to carry out the extraction. This obtained extract was subjected to preliminary phytochemical screening and in vitro alpha-amylase activity. At 16 mg/mL, acarbose displayed 78.40 ± 0.36% inhibition, whereas the extract exhibited 72.96 ± 0.70% inhibition, which is significantly comparable. The IC₅₀ value of acarbose was 12.9 ± 1.12, whereas the extract exhibited 13.31 ± 1.12 mg/mL. The extract possesses numerous classes of chemicals such as alkaloids, glycosides, tannins, polyphenols, and terpenoids, which can contribute to the antidiabetic activity through alpha-amylase inhibition. This was an initial exploration of the work as a proof of concept for the development of polyherbal tea bag formulation for the treatment of diabetes. In the future, we are aiming to investigate the effectiveness of polyherbal tea bags in the treatment of diabetes using more in vitro and in vivo models. From the present investigation, we have concluded that this extract can be used for the treatment of diabetes.

Characterization of the aroma profiles of oolong tea made from three tea cultivars by both GC-MS and GC-IMS

Tea cultivar is crucial for oolong tea aroma quality. However, the aroma characteristics of oolong tea made from different cultivars have rarely been studied. The aroma profiles of fresh tea leaves and oolong teas derived from Shuixian (SX), Huangmeigui (HMG) and Zimudan (ZMD) cultivars were comprehensively analyzed by gas chromatography-mass spectrometry, gas chromatography-ion mobility spectrometry (GC-IMS), sensory evaluation and odor activity value (OAV) determination. 12 volatiles (OAV＞1) contributed to the overall aroma, of which benzeneacetaldehyde (OAV 2.14) and 3,5-diethyl-2-methylpyrazine (OAV 1.25) were the aroma-active compounds for HMG tea. Significantly more volatiles and stronger floral odor were from HMG and ZMD than the SX tea. Moreover, popcorn-like, creamy odors with high-intensity, and caramel-like odor were only recorded in HMG and ZMD samples. Additionally, 27 volatiles were identified by GC-IMS only, indicating the benefits of combined method for a better understanding of the impact of cultivars on tea aroma profiles.

HS-SPME and GC/MS volatile component analysis of Yinghong No. 9 dark tea during the pile fermentation process

Each type of tea has a unique volatile profile due to its variety, processing technologies and origin. Using HS-SPME and GC/MS, we analyzed the changes of volatile components in cultivar Yinghong No. 9 during pile-fermentation every 10 days. A total of 94 compounds showed significant differences during a total of 60 days mainly including alkanes, ketones, esters, terpenes, aromatics and heterocyclic compounds. Interestingly, 13 metabolites were progressively reduced during the first 20 days and remained unchanged in subsequent procedures, while 17 metabolites remained unchanged in the early stage and progressively increased during the last 20 days of pile fermentation, indicating that they are characteristic volatile compounds of raw material sun-dried green tea and dark tea, respectively. β-ionone, phenylethyl alcohol, and a-ionone could be the top three contributed aroma compounds in the final dark tea. Our study provides a theoretical basis for process and quality improvement of Yinghong No. 9.

Analysis of volatile compounds in rooibos tea (Aspalathus linearis) using different extraction methods and their relationship with human sensory perception

This study aimed to comparatively analyze the volatile flavor of rooibos tea (Aspalathus linearis) obtained by two commonly used flavor extraction methods, simultaneous distillation-extraction (SDE) and steam distillation under reduced pressure (DRP). The tea obtained by the two extraction methods, were analyzed by gas chromatography-mass spectrometry to identify volatile aroma-related compounds. Descriptive sensory analysis of the extracted rooibos tea flavor was carried out by a trained panel (n = 7). Fifty volatile compounds were identified, including 26 and 25 aroma-active compounds by SDE (45.9 µg/g) and DRP (37.5 µg/g), respectively. SDE recovered larger quantities of alcohols, acids, and esters, whereas DRP was useful for analyzing thermally unstable volatile compounds, including various alcohols, aldehydes, and hydrocarbons. Descriptive sensory analysis revealed that ketones and phenolic compounds may be responsible for the sensory attributes woody and grassy green, whereas the aldehydes and acidic compounds may contribute to floral and fruity.

Sensory and Volatile Flavor Analysis of Beverages

Humans have used their senses to evaluate food for several thousands of years [...].