Santona Mario, Sanna Maria Lina, Multineddu Chiara, Fancello Francesco, de la Fuente Sara Audije, Dettori Sandro, Zara Severino
Dipartimento di Scienze della Natura e del Territorio, Via De Nicola, University of Sassari, 07100 Sassari, Italy.
Dipartimento di Agraria, Viale Italia 39, University of Sassari, 07100 Sassari, Italy.
Food Microbiol. 2018 Apr;70:65-75. doi: 10.1016/j.fm.2017.09.004. Epub 2017 Sep 11.
The olives are rich in microorganisms that, during the extraction process may persist in the oils and can influence their physicochemical and sensory characteristics. In this work, and for the first time, we isolated and identified microbial species, yeast and bacteria, present during the production process in four Sardinian (Italy) oleic ecosystems. Among these varieties, we found that Nera di Gonnos was associated to the highest microbial biodiversity, which was followed by Bosana, Nocellara del Belice and Semidana. Among the different microbial species isolated, some are specific of olive ecological niches, such as Cryptococcus spp and Serratia spp; and others to olive oils such as Candida spp and Saccharomyces. Some other species identified in this work were not found before in oleic ecosystems. The enzymatic analyses of yeast and bacteria showed that they have good β-glucosidase activity and yeast also showed good β-glucanase activity. The majority of bacteria presented lipolytic and catalase activities while in yeast were species-specific. Interestingly, yeast and bacteria isolates presented a high resistance to bile acid, and about 65% of the yeast were able to resist at pH 2.5 for 2 h. Finally, bacteria showed no biofilm activity compared to yeast.
橄榄富含微生物，在提取过程中这些微生物可能会残留在油中，并影响其物理化学和感官特性。在这项工作中，我们首次在意大利撒丁岛的四个油橄榄生态系统的生产过程中分离并鉴定了微生物种类，包括酵母和细菌。在这些品种中，我们发现内拉迪贡诺斯（Nera di Gonnos）的微生物生物多样性最高，其次是博萨纳（Bosana）、贝利切诺切拉腊（Nocellara del Belice）和塞米达纳（Semidana）。在分离出的不同微生物种类中，一些是油橄榄生态位特有的，如隐球菌属（Cryptococcus spp）和沙雷氏菌属（Serratia spp）；其他一些则是橄榄油特有的，如假丝酵母属（Candida spp）和酿酒酵母（Saccharomyces）。在这项工作中鉴定出的其他一些物种以前在油橄榄生态系统中未曾发现。对酵母和细菌的酶分析表明，它们具有良好的β-葡萄糖苷酶活性，酵母还具有良好的β-葡聚糖酶活性。大多数细菌具有脂肪分解和过氧化氢酶活性，而酵母的活性则具有物种特异性。有趣的是，酵母和细菌分离株对胆汁酸具有高度抗性，约65%的酵母能够在pH 2.5下耐受2小时。最后，与酵母相比，细菌没有生物膜活性。
