Skenderidis Prodromos, Leontopoulos Stefanos, Petrotos Konstantinos, Mitsagga Chrysanthi, Giavasis Ioannis
Laboratory of Food and Biosystems Engineering, Department of Agrotechnology, University of Thessaly, 41110 Larissa, Greece.
Laboratory of Food Microbiology, Department of Food Technology, University of Thessaly, End of N. Temponera Street, 43100 Karditsa, Greece.
Plants (Basel). 2021 Aug 24;10(9):1757. doi: 10.3390/plants10091757.
The present study aimed to assess the antimicrobial properties of encapsulated lyophilized powdered extracts of pomegranate peels (PP), avocado peels (AP) and avocado seeds (AS) in vitro and in vivo. Minimum Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC) methods, optical density measurement, and well diffusion assay were used to determine antimicrobial activity against food borne bacteria (Gram- ), (Gram+ ), and fungi () based on a mixture design model. Additionally, the most effective powder was studied in vivo in yogurt, cream cheese, and minced meat burger. The samples that contained high polyphenol content also exhibited higher antioxidant, antimicrobial, and antifungal activity. From the results of the well diffusion, the MIC/MBC, and the cell optical density assays, the antimicrobial activity of the extracts was found to be correlated to the total phenolic content (TPC) of the samples and the type of the microorganism. The pomegranate peels extract presented the higher TPC and antioxidant activity and constitute the highest percentage in the most active antimicrobial mixture. The powders that were tested in vitro showed microbial type-dependent effects in each food model. The results presented here can be further studied in the large-scale industrial production of natural food preservatives.
本研究旨在评估石榴皮（PP）、鳄梨皮（AP）和鳄梨籽（AS）的冻干粉末提取物在体外和体内的抗菌性能。采用最低抑菌浓度（MIC）和最低杀菌浓度（MBC）方法、光密度测量和打孔扩散法，基于混合设计模型测定对食源细菌（革兰氏阴性菌、革兰氏阳性菌）和真菌的抗菌活性。此外，在酸奶、奶油奶酪和碎肉汉堡中对最有效的粉末进行了体内研究。含有高多酚含量的样品也表现出更高的抗氧化、抗菌和抗真菌活性。从打孔扩散、MIC/MBC和细胞光密度测定结果来看，提取物的抗菌活性与样品的总酚含量（TPC）和微生物类型相关。石榴皮提取物呈现出较高的TPC和抗氧化活性，并且在最具活性的抗菌混合物中占比最高。体外测试的粉末在每种食品模型中均显示出微生物类型依赖性效应。此处呈现的结果可在天然食品防腐剂的大规模工业生产中进一步研究。
