Effects of Tea Powder on the Cooking Properties, Antioxidative Potential and Volatile Profiles of Dried Noodles

Identification of key odorants responsible for the seaweed-like aroma quality of Shandong matcha

The distinctive seaweed-like aroma is a typical flavor characteristic of high-grade Shandong matcha. To obtain a sample of strong seaweed aroma extracted from matcha, high-grade Shandong matcha made from fresh leaves of Camellia sinensis cv. Zhongcha 108 was steeped at 70 °C with a 1:6 tea to water ratio. A total of 11 volatile components that contribute significantly to the aroma of Shandong matcha were identified using headspace solid-phase microextraction combined with gas chromatography mass spectrometry (HS-SPME-GC/MS) and gas chromatography mass spectrometry combined with olfaction (GC-O-MS). These volatile components include dimethyl sulfide (DMS), α-Ionone, hexanal, benzaldehyde, (E)-β-ionone, (E, E)-2,4-heptadienal, (Z)-2-penten-1-ol, 1-penten-3-ol, β-cyclocitral, 3-methyl butanal, Nonanal. Further aroma recombination and omission experiments reveal that DMS (P < 0.001), α-ionone (P < 0.001), hexanal (0.001 < P < 0.01), benzaldehyde (0.001 < P < 0.01), and (E)-β-ionone (0.01 < P < 0.05) are key contributors to the seaweed fragrance, with DMS and α-Ionone being the main aroma components. This study identified the key aroma compounds of seaweed-like in Shandong matcha, explored the synergistic and antagonistic effects between these aroma components, and provided a theoretical basis for the quality control and scientific brewing of Shandong matcha.

Effect of Flammulina velutipes Soluble Dietary Fiber on Dough Processing Characteristics and Micro-Fermented Dried Noodles Quality Properties

Our research focused on the integration of Flammulina velutipes soluble dietary fiber (Fv-SDF) into wheat flour during the production of dried noodles, delving into the impact of different addition ratios of Fv-SDF on both dough processing characteristics and the quality of the micro-fermented dried noodles. The viscometric and thermodynamic analyses revealed that Fv-SDF notably improved the thermal stability of the mix powder, reduced viscosity, and delayed starch aging. Additionally, Fv-SDF elevated the gelatinization temperature and enthalpy value of the blend. Farinograph Properties and dynamic rheology properties further indicated that Fv-SDF improved dough formation time, stability time, powder quality index, and viscoelasticity. Notably, at a 10% Fv-SDF addition, the noodles achieved the highest sensory score (92) and water absorption rate (148%), while maintaining a lower dry matter loss rate (5.2%) and optimal cooking time (142 s). Gas chromatography-ion mobility spectrometry (GC-IMS) analysis showed that 67 volatile substances were detected, and the contents of furfural, 1-hydroxy-2-acetone, propionic acid, and 3-methylbutyraldehyde were higher in the Fv-SDF 10% group. These 10% Fv-SDF micro-fermented noodles were not only nutritionally enhanced, but also had a unique flavor. This study provides a valuable theoretical basis for the industrial application of F. velutipes and the development of high-quality dried noodles rich in Fv-SDF.

Functional instant noodle formulation for emergency conditions: Sensory and stability characteristics

The aim of this study was to evaluate the shelf-life and sensory characteristics of a functional instant noodle preparation designed to be used in emergencies as a tactical ration. Instant noodles were selected for their global acceptability and ease of preparation. In this study, semolina flour was used as the main ingredient, and soy protein isolate was added to increase the protein content. Additionally, green tea and beef tallow were incorporated to decrease the likelihood of oxidation. Carboxymethyl cellulose was added to increase the porosity and water absorption of the dry noodles. Spirulina powder was used as a dressing for the final product before serving to increase the nutritional value and provide the consumer with the required vitamins and minerals of the day. Physical, chemical, and organoleptic properties were assessed at multiple timepoints in a 120-day period to perform an accelerated shelf-life test by determining their critical moisture content and moisture sorption isotherm curves at 30, 45, and 55°C. The shelf-life of the product was evaluated to be 1197.28 days at 30°C and 75% relative humidity in aluminum pouches. In conclusion, the product is shelf-stable at room temperature and is recommended to be stored and used in disaster conditions such as earthquakes, floods, and wars.

Pruned tea biomass plays a significant role in functional food production: A review on characterization and comprehensive utilization of abandon-plucked fresh tea leaves

Tea is the second largest nonalcoholic beverage in the world due to its characteristic flavor and well-known functional properties in vitro and in vivo. Global tea production reaches 6.397 million tons in 2022 and continues to rise. Fresh tea leaves are mainly harvested in spring, whereas thousands of tons are discarded in summer and autumn. Herein, pruned tea biomass refers to abandon-plucked leaves being pruned in the non-plucking period, especially in summer and autumn. At present, no relevant concluding remarks have been made on this undervalued biomass. This review summarizes the seasonal differences of intrinsic metabolites and pays special attention to the most critical bioactive and flavor compounds, including polyphenols, theanine, and caffeine. Additionally, meaningful and profound methods to transform abandon-plucked fresh tea leaves into high-value products are reviewed. In summer and autumn, tea plants accumulate much more phenols than in spring, especially epigallocatechin gallate (galloyl catechin), anthocyanins (catechin derivatives), and proanthocyanidins (polymerized catechins). Vigorous carbon metabolism induced by high light intensity and temperature in summer and autumn also accumulates carbohydrates, such as soluble sugars and cellulose. The characteristics of abandon-plucked tea leaves make them not ideal raw materials for tea, but suitable for novel tea products like beverages and food ingredients using traditional or hybrid technologies such as enzymatic transformation, microbial fermentation, formula screening, and extraction, with the abundant polyphenols in summer and autumn tea serving as prominent flavor and bioactive contributors.

A comprehensive review of matcha: production, food application, potential health benefits, and gastrointestinal fate of main phenolics

Matcha, a powder processed from tea leaves, has a unique green tea flavor and appealing color, in addition to many other sought after functional properties for a wide range of formulated food applications (e.g., dairy products, bakery products, and beverage). The properties of matcha are influenced by cultivation method and processing post-harvest. The transition from drinking tea infusion to eating whole leaves provides a healthy option for the delivery of functional component and tea phenolics in various food matrix. The aim of this review is to describe the physico-chemical properties of matcha, the specific requirements for tea cultivation and industrial processing. The quality of matcha mainly depends on the quality of fresh tea leaves, which is affected by preharvest factors including tea cultivar, shading treatment, and fertilization. Shading is the key measure to increase greenness, reduce bitterness and astringency, and enhance umami taste of matcha. The potential health benefits of matcha and the gastrointestinal fate of main phenolics in matcha are covered. The chemical compositions and bioactivities of fiber-bound phenolics in matcha and other plant materials are discussed. The fiber-bound phenolics are considered promising components which endow matcha with boosted bioavailability of phenolics and health benefits through modulating gut microbiota.

Characterization of the Key Aroma Compounds of Shandong Matcha Using HS-SPME-GC/MS and SAFE-GC/MS

Shandong matcha has the quality characteristics of bright green color, seaweed-like aroma and strong, fresh and brisk taste. In order to identify the characteristic aroma components and clarify the contribution of the grinding process to the aroma of Shandong matcha. Three grades of Shandong matcha and corresponding tencha material were firstly tested with sensory evaluation, and the volatile components were extracted with headspace solid-phase microextraction (HS-SPME) and solvent-assisted flavor evaporation (SAFE) and analyzed using GC–MS. The sensory evaluation results showed that high-grade matcha (M-GS) had prominent seaweed-like, fresh and roasted notes, whereas medium and low-grade matcha (M-G1, M-G2) were gradually coupled with grassy, fatty and high-fired aromas. GC–MS results showed that in the HS-SPME method, heterocyclic compounds (45.84–65.35%) were the highest in Shandong matcha, followed by terpenoids (7.44–16.92%) and esters (6.91–15.27%), while in the safe method, esters were the highest (12.96–24.99%), followed by terpenoids (10.76–25.09%) and heterocyclic compounds (12.12–17.07%). As a whole, the composition of volatile components between M-G1 and M-G2 is relatively close, and there are more differences in volatile components between them and M-GS. The volatile components unique to M-GS were screened using the odor activity value (OAV) evaluation method, with components such as 3-methyl-2-butene-1-thiol, 3-ethyl-Phenol, 2-thiophenemethanethiol, 2,4-undecadienal, (E,E)-2,6-nonadienal, (E,Z)- being evaluated. There were other differentially volatile components, that is, volatile components that coexist in the three grades of matcha, but with different concentrations and proportions. M-G1 and M-G2 contained more volatile substances with high-fired aroma, such as 2-ethyl-3-methyl-pyrazine, coumarin and 5,6,7,8-tetrahydroquinoxaline. The grinding process not only changes the appearance of tencha, but also increases the content of volatile components of matcha as a whole, enhancing the aroma and flavor characteristics of matcha. In this study, the contents of 24 volatile components in matcha were mainly increased, such as benzene, (2,2-dimethoxyethyl)-, cis-7-decen-1-al, safranal and fenchyl acetate. The dual factors of material tencha and matcha grinding technology are indispensable in forming the differences in aroma and flavor of Shandong matcha at different levels.

Effects of Multiscale Mechanical Pulverization on the Physicochemical and Functional Properties of Black Tea

Black tea leaves were pulverized at an organ-scale (~mm), tissue-scale (500−100 μm) and cell-scale (<50−10 μm) to investigate their physicochemical and functional properties. The results showed that cell-scale powders exhibited a bright brown color compared with organ- or tissue-scale powders with the highest total color difference (∆E) of 39.63 and an L value of 55.78. There was no obvious difference in the oil-holding capacity (OHC) of the organ- and tissue-scale powders (3.71−3.74 g/g), while the OHC increased significantly to 4.08 g/g in cell-scale powders. The soluble dietary fiber (SDF) content of cell-scale powders increased remarkably to 10.41%, indicating a potential application as a high-SDF food. Further, cell-scale pulverization of black tea enhanced its DPPH scavenging activity and ferric-ion-reducing antioxidant power (FRAP). However, the polyphenol content (13.18−13.88%) and the protein content (27.63−28.09%), as well as the Pb2+ adsorption capacity (1.97−1.99 mg/g) were not affected by multiscale pulverizations. The mean particle size (D50) correlated linearly with tap density (TD), color parameters of L and b, SDF content, DPPH scavenging activity and FRAP. The results indicate that black tea powders pulverized at a cell-scale can be used as a soluble fiber-rich functional food additive with a bright color, enhanced OHC and antioxidant capacity.