Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1–3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3-O-caffeoylquinic acid (32.7 mg, 95.7%), 1,5-O- dicaffeoylquinic acid (4.3 mg, 97.2%), 3-O-caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3-O-dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5-O-dicaffeoyl-3-O-(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5-O-dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5-O-dicaffeoyl-3-O-succinylquinic acid (8.7 mg, 93.4%), and 1,5-O-dicaffeoyl-4-O-succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4-O-dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5-O-dicaffeoyl-3-O-succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

Ginger is one of the most popular spices and medical herbs with its unique pungent flavour and taste. Although there has been much research into the drying methods of ginger, the effect of drying parameters in hot air convective drying on ginger quality needs to be explored in depth. This study investigated the differences in drying behaviour and quality characteristics of ginger with the variables of temperature, thickness, and loading density. The moisture states and diffusion pattern in the different stages during the drying process were analysed using low-field NMR techniques. The results of quality evaluation showed that the temperature greatly influenced the colour and gingerol content of dried ginger, and the thickness of a ginger slice greatly influenced the rehydration rate. Optimal drying conditions were determined by considering a combination of specific energy consumptions with quality retention based on the response surface methodology: a temperature of 66.41 °C, thickness of 2 mm, and loading density of 5 kg/m². HS-GC-IMS combined with multivariate chemometrics was used to achieve the characterisation of flavour profiles and fingerprinting of dried ginger. The principal component analysis and correlation analysis revealed that the alterations in ginger quality were intimately related to moisture diffusion during drying.

American ginseng (AG) has long been used as an ingredient in the food and pharmaceutical industries because of its nutritional and economic value. AG is rich in nutrients, and its quality is greatly affected by how it is processed. However, there is a relative paucity of research on the comprehensive evaluation of different processing techniques of AG. This study evaluated the differences in quality formation and properties of low-temperature softened, blanched, steamed followed by hot air drying, and vacuum freeze-dried AG (LTS-HAD, BL-HAD, ST-HAD, and VFD, respectively). The results demonstrated that AGs treated with VFD had the fastest drying time (85 h) and succeeded in preserving the color and microstructure of fresh ginseng. The contents of ginsenoside Rg1 and Rb1 in LTS-HAD samples were 2.81 ± 0.01 mg/g and 10.68 ± 0.66 mg/g, respectively, which were significantly higher than those in VFD samples (p < 0.05). Moreover, ST-HAD samples had an attractive reddish-brown appearance and higher antioxidant activity. Simultaneously, the formation of the ginsenosides Rg6, (S) Rg3, (R) Rg3, Rk1, and Rg5 was discovered. BL-HAD samples had an intermediate quality among the above samples. A total of 58 volatile compounds were identified, including aldehydes (14), alcohols (13), ketones (10), esters (6), terpenes (6), acids (5), and heterocyclic compounds (4). PCA of ginsenosides and volatile components, as well as correlation analysis with color and antioxidant activity, resulted in the identification of different processed products and potential bioactive components.

Gastrodiae Rhizoma (GE), a popular food in China, is stored and consumed after steaming, which can lead to the degradation of active substances and a decrease in its quality. Therefore, this study explored the potential application of ultra-high-pressure (UHP)-assisted hot air drying in improving the quality of GE. The results indicated that UHP pre-treatment could preserve the original cross-sectional color of GE and increase the degrees of freedom of water in GE samples. Compared with traditional steaming pre-treatment (18 h), UHP pre-treatment at 500 MPa significantly shorted the time (10 h) required for the GE samples to reach drying equilibrium. Meanwhile, the UHP-assisted hot air drying method (60 °C) could reduce the activity of β-D-glucosidase and avoid the degradation of active substances. Finally, UHP pre-treatment improved the neuroprotective activity in vivo. Overall, UHP-assisted hot air drying could improve the quality of GE samples. This study provides a simple method for improving the quality of GE samples and offers a reference for subsequent research on the influence of UHP on GE.

Lonicerae japonicae flos (LJF) is a natural product with medicinal, edible, and ornamental value which has been developed into LJF tea. At present, LJF tea can be processed using four main fixation methods: fixation by sun drying (SG), hot-air oven drying (HG), stir-frying drying (CZ), and steaming (ZZ). However, a comparative analysis of the effects of different fixation methods on the quality of LJF tea has not been reported. This study comprehensively investigated the effects of these fixation methods on the appearance color, volatile components, and non-volatile components of LJF tea samples. Our findings demonstrated that LJF tea in the SG group had the highest L value, causing a brighter appearance, which was mainly caused by the retention of organic acids and flavonoids. Additionally, LJF tea in the SG group had a higher content of aroma components than other groups. These results suggested that sun drying may be beneficial for improving the quality of LJF tea. This study provided a reference for the selection of fixation methods for LJF tea and offered a clue for quality improvement of LJF tea.