Effects of processing procedures on the formation of aroma intensity and odor characteristic of Benshan tea (Oolong tea, Camellia sentences)

Chemical Composition of Essential Oils and Their Potential Applications in Postharvest Storage of Cereal Grains

Insect infestation and microbial, particularly mold contamination, are the major causes of stored grain deterioration during postharvest storage, which results in a significant loss in grain quality and quantity, and the formation of toxic chemicals such as mycotoxins. Pesticides, together with physical protection strategies, have been widely used to control insects and molds in stored grains, but their uses present significant environmental and health problems. This has led to the exploration of safer pesticide alternatives. Essential oils (EOs) are highly concentrated materials extracted from leaves, stems, flowers, seeds, roots, fruit rinds, resins, or barks. They are multifunctional due to their complex chemical composition. Thus, EOs are frequently used for their therapeutic, antimicrobial, odoriferous, and flavor properties in a wide range of products like medicine, cosmetics, and foods. This review provides comprehensive information on the chemical compositions of EOs commonly used in the food industry, factors influencing EO composition, and recent studies on the potential of EOs as alternatives to synthetic pesticides and fungicides for stored grain protection. The relationship between chemical compositions of EOs and their anti-insects and antimicrobial potentials, as well as current approaches/technologies of using EOs for food preservation, are also covered. However, this review also highlights the need for research on the development of feasible and affordable methodologies to apply effective EOs or encapsulated EOs in grain storage settings, particularly for organic grain protection.

Study on the correlation between color and taste of beauty tea infusion and the pivotal contributing compounds based on UV-visible spectroscopy, taste equivalent quantification and metabolite analysis

This study utilized a colorimeter to determine the color values of 23 beauty tea (BT) samples, the color and the taste characteristics were also quantitatively described through ultraviolet-visible (UV-Vis) spectroscopy and taste equivalent quantification. Furthermore, metabolomic analysis was conducted by using ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS). Correlation analysis was employed to preliminarily identify the compounds that contribute to the color and taste of BT infusion. Finally, the contributing compounds were further determined through verification experiment. The results showed that within a certain range, as the color of BT infusion deepened, the taste became stronger, more bitter and astringent, while on the contrary, it became sweeter and mellower. Theaflavins, kaempferol, astragalin, and 5-p-coumaroylquinic acid influenced both the color and taste of the BT infusion. Gallic acid was also determined as a contributor to the color. This study provides new insights into research on tea quality in infusion color and taste aspects.

Analysis of the effect of different withering methods on tea quality based on transcriptomics and metabolomics

Withering is very important to the quality of Wuyi rock tea. In this study, transcriptomics and metabolomics were used to analyze the effects of different withering methods on tea quality formation. The results showed that sunlight withering (SW) was most beneficial in increasing the gene expression of ubiquinone and other terpenoid-quinone biosynthesis (ko00130), pyruvate metabolism (ko00620), starch and sucrose metabolism (ko00500), and tryptophan metabolism (ko00380) pathways, and increasing the content of nucleotides and derivatives, terpenoids, organic acids and lipids, thus enhancing the mellowness, fresh and brisk taste and aroma of tea. Withering trough withering (WW) was most beneficial in increasing the gene expression of glutathione metabolism (ko00480), phenylpropanoid biosynthesis (ko00940) pathways, increasing the content of phenolic acids and flavonoids, thus enhancing tea bitterness. A comprehensive evaluation of the metabolite content and taste characteristics of tea leaves showed SW to be the best quality and charcoal fire withering (FW) to be the worst quality. This study provided an important basis for guiding the processing of Wuyi rock tea with different flavors.