Comparative studies on flavor substances of leaves and pericarps of Zanthoxylum bungeanum Maxim. at different harvest periods

Purpose: To study the transformation of the aroma components and pungent constituents of Zanthoxylum bungeanum Maxim. (ZBM) leaves and pericarps at different periods, and to provide a basis for selecting an appropriate harvest time for the pericarps and leaves.Methods: Quantitative analysis of the pungent components of ZBM leaves and pericarps was performed by high performance liquid chromatography (HPLC) while their aroma constituents were analyzed by headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS).Results: HPLC analysis revealed that hydroxy-α-sanshool was the predominant pungent component in both the leaves and pericarps of different parts of ZBM at different harvest periods, followed by hydroxy- γ-sanshool and hydroxy-β-sanshool. During the growth of ZBM, the contents of pungent substances in the leaves declined gradually, while pungent substances in the pericarps increased. The results of HSSPME- GC-MS analysis showed that linalyl acetate, linalool and limonene were the major aroma components of the leaves and pericarps of ZBM at different harvest periods. During the growth of ZBM, the contents of monoterpenes in the leaves decreased gradually, whereas monoterpenes in the pericarps increased.Conclusion: These results suggest that the pungent and aroma components produced in ZBM at early developmental stages are stored in the leaves, and are gradually transferred to the pericarps at the final developmental stages. Thus, the leaves of ZBM can be used as a new source of food and medicine.Keywords: Zanthoxylum bungeanum Maxim., Pericarp, Pungent components, Aroma component

Inhibitory Effect of Allyl Isothiocyanate on Clostridium perfringens and Its Application of Cooked Pork

The study aimed to investigate the inhibitory activity and mechanism of action of allyl isothiocyanate (AITC) against Clostridium perfringens (C. perfringens). Firstly, the inhibitory effect of AITC on C. perfringens was evaluated by determining the minimum inhibitory concentration (MIC) and plotting the growth curve. Secondly, the effect of AITC on C. perfringens cell membranes was assessed by scanning electron microscopy to observe cell morphology and by measuring cell membrane integrity with a propidium iodide staining assay. In addition, the impact of AITC on the metabolism of C. perfringens was investigated using SDS-PAGE profile and an ATPase activity assay. Finally, the inhibitory effect of AITC on C. perfringens in cooked ground pork was examined. The experimental results showed that AITC could effectively inhibit the growth of C. perfringens, and the MIC of AITC was determined to be 0.1 μL/mL. AITC was able to induce cell membrane deformations, such as rupture and depression, resulting in the loss of C. perfringens cell membrane integrity, and the degree of membrane damage increased with AITC concentration. Meanwhile, AITC could reduce the protein content and ATPase activity of C. perfringens, which had an impact on normal cellular metabolism. Furthermore, the addition of 0.1%~0.4% AITC significantly inhibited the growth of C. perfringens in cooked ground pork (P<0.05). In conclusion, AITC could achieve bacterial inhibition by disrupting the cell membrane of C. perfringens and interfering with protein metabolism, and this study offered a theoretical foundation for the use of natural bacterial inhibitors in the meat industry