Elsevier

Powder Technology

Volume 339, November 2018, Pages 560-568
Powder Technology

Effect of vibrating-type ultrafine grinding on the physicochemical and antioxidant properties of Turkish galls in Uyghur medicine

https://doi.org/10.1016/j.powtec.2018.07.095Get rights and content

Highlights

  • Vibrating-type ultrafine grinding could obtain TGP with different particle sizes.

  • The content of three chemical constituents were increased after ultrafine grinding.

  • Antioxidant activities of TGP extracts were improved.

  • The analysis of FTIR and SEM indicated that the main structure of the constituents not be altered.

  • The microscopic identification exhibited the powder features.

Abstract

We evaluated the influence of a vibrating-type ultrafine grinding treatment on the physical and chemical properties and antioxidant activity of Turkish gall powder (TGP) with particle sizes of >450, 400–250, 250–100, 100–50, and < 50 μm. The physical properties were analyzed and we found that the small particle size of the TGP increased the bulk (from 0.68 to 0.32 g/cm3) and tapped densities (from 0.83 to 0.70 g/cm3) and increased the repose (from 35.43° to 56.28°), slide (from 35.54° to 59.23°), and crash angles (from 35.68° to 42.91°). The total ash content (from 2.34% to 1.75%) decreased, but the moisture index and water solubility index were improved. The extract of TGP with a particle size of <50 μm indicated that highest gallic acid content (9.47 mg/g), methyl gallate content (34.78 mg/g) and ellagic acid contents (0.79 mg/g) accompanied with the best DPPH, hydroxyl radical, and superoxide radical scavenging activities (p < .05). Moreover, the FTIR analysis suggested that the ultrafine grinding did not damage the main structure of the components as the particle sizes decreased. The SEM images demonstrated the shape of the TGP with different particle sizes and surface morphology. The microscopic identification exhibited the vessels, oil cells, starch grains, and cluster crystals, which provided referential information in evaluating the Turkish gall quality.

Introduction

Traditional Chinese medicine Turkish galls (galls of Quercus infectoria) have been used medicinally by Uyghur natives and are commonly known as “Moza” in Uyghur literature [1]. Quercus infectoria Olivier (Fagaceae) is an oak shrub species that is mainly present in Turkey, Greece, Syria, and Iran [2], which is a popular Uyghur medicinal plant. Female gall wasps use their ovipositor to stab the young branches of this shrub and spawn. The shrub is stimulated to grow tissue around the larvae. A gall forms when starch grains disappear around the larvae [3]. The main components of Turkish galls are tannin and a small amount of free gallic acid, methyl gallate, and ellagic acid [4]. The galls are used as a constituent of toothpowder and in the treatment of gingivitis and toothache in Uyghur traditional medicine [5]. Additionally, Turkish galls exhibit various biological properties, including antioxidative [2], anti-inflammatory [6], and antimicrobial [7]. Turkish galls should be further considered and investigated for the treatment of colon cancer [1], and their therapeutic potential should be studied.

The active ingredients of drugs mainly exist between the cytoplasm and nucleus. Their efficacy is hardly manifested when the cells are intact [8]. This phenomenon is one of the reasons that the curative effect of traditional Chinese medicine is not evident at high dosages [9]. Ultrafine grinding technology has been broadly applied in traditional Chinese medicine processing [10]. Herbal medicine is ground to dissolve the active components of the cells; hence, the drug can work rapidly and effectively [11]. After ultrafine grinding, only a few intact cells are observed using scanning electron microscopy [10]. The vibrating-type ultrafine grinder is an effective tool for preparing herbal medicines. The herbal material is mixed with the grinding media by using a rod in the grinding chamber where the material is strongly crushed, compressed, and sheared in a short period of time. This grinding technique breaks the cell walls of the plants or animal medicinal materials to improve their bioavailability [12]. The vibrating-type ultrafine grinder is efficient and energy saving. Meanwhile, it can alter the physicochemical properties of the materials, including moisture content, water solubility, and flowability [9]. Moreover, the advancing technology is expanding the application of the vibrating-type ultrafine grinder to other fields, such as in agriculture [13], electronic materials [14], energy-saving technology and other industries [15].

To the best of our knowledge, the effects of the vibrating-type ultrafine grinder on Turkish galls have not been reported. Therefore, this study aimed to comparatively study the five stages of Turkish gall powders (TGPs) and their physicochemical properties and antioxidant activities. This study explored the application of the vibrating-type ultrafine grinding technique in Turkish galls. The second objective of this study was to provide a reference in improving the product quality of Turkish galls as medicine.

Section snippets

Materials

Dried Turkish galls were provided by Xinjiang Ciconhabo Uyghur Medicine Co. Ltd. (Urumqi, Xinjiang province, China). DPPH (1, 1-diphenyl-2-picrylhydrazyl), salicylic acid, tris-hydroxymethyl aminomethane, pyrogallic acid were purchased from Sigma Chemical Co. (St. Louis, MO, USA). Gallic acid standard, methyl gallate standard and ellagic acid reference substances (purity≥99%) were bought from the Chinese Institute for the Control of Pharmaceutical and Biological Products. (Beijing, China).

Moisture and total ash contents of TGP

As shown in Table 1, the moisture index of TGP with different sizes slowly raised with decreasing particle size (from 3.25% to 6.01%, p < .05). A large specific surface area increased the contact with air and facilitated moisture absorption [8]. The total ashes content of the smaller particle size was less (p < .05). After high-temperature burning, the organic composition volatilized and the remaining inorganic components were pure ashes. A small particle size allowed complete combustion and

Conclusion

With unremitting efforts, we investigated the effect of the vibrating-type ultrafine grinding on Turkish galls. Powders with different particle sizes were obtained. The influence of the different sizes of the powders on the chemical components, physical properties, and antioxidant properties of the Turkish galls were researched. Results indicated that the vibrating-type ultrafine grinding effectively reduce the particle size of the Turkish galls. Moreover, it also altered physical properties of

Acknowledgements

Financial support of this work was supported by the Xinjiang Uygur Autonomous Region of the major science and technology projects in China (Grant numbers 201704503).

Competing interests

The author declares that she has no conflicts of interest related to this study.

References (31)

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