Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science & Technology, Agricultural University of Athens, Iera Odos, Votanikos, Athens, Greece.
J Appl Microbiol. 2010 Feb;108(2):396-405. doi: 10.1111/j.1365-2672.2009.04424.x.
To assess the yeast community structure and dynamics during Greek-style processing of natural black Conservolea olives in different brine solutions.
Black olives were subjected to spontaneous fermentation in 6% (w/v) NaCl brine solution or brine supplemented with (i) 0.5% (w/v) glucose, (ii) 0.2% (v/v) lactic acid and (iii) both glucose and lactic acid. Yeast species diversity was evaluated at the early (2 days), middle (17 days) and final (35 days) stages of fermentation by restriction fragment length polymorphism and sequence analyses of the 5.8S internal transcribed spacer and the D1/D2 ribosomal DNA (rDNA) regions of isolates. Analysis revealed a relatively broad range of biodiversity composed of 10 genera and 17 species. In all treatments, yeasts were the main micro-organisms involved in fermentation together with lactic acid bacteria that coexisted throughout the processes. Metschnikowia pulcherrima was the dominant yeast species at the onset of fermentation, followed by Debaryomyces hansenii and Aureobasidium pullulans. Species heterogeneity changed as fermentations proceeded and Pichia membranifaciens along with Pichia anomala evolved as the main yeasts of olive elaboration, prevailing at 17 and 35 days of the process. Molecular techniques allowed for the identification of five yeast species, namely A. pullulans, Candida sp., Candida silvae, Cystofilobasidium capitatum and M. pulcherrima, which have not been reported previously in black olive fermentation.
By using molecular techniques, a rich yeast community was identified from Conservolea black olive fermentations. Metschnikowia pulcherrima was reported for the first time to dominate in different brines at the onset of fermentation, whereas Pichia anomala and P. membranifaciens evolved during the course. The addition of glucose and/or lactic acid perturbed yeast succession and dominance during fermentation.
Yeasts have an important role in black olive fermentation and contribute to the development of the organoleptic characteristics of the final product. At the same time, certain species can cause significant spoilage. The present study adds to a better knowledge of yeast communities residing in olive fermentations towards a well-controlled process with minimization of product's losses.
评估希腊式加工天然黑 Conservolea 橄榄在不同盐水中的酵母群落结构和动态。
黑橄榄在 6%（w/v）NaCl 盐水中或添加（i）0.5%（w/v）葡萄糖、（ii）0.2%（v/v）乳酸和（iii）葡萄糖和乳酸的盐水中进行自发发酵。通过限制片段长度多态性和分离物的 5.8S 内部转录间隔区和 D1/D2 核糖体 DNA（rDNA）区域的序列分析，在发酵的早期（2 天）、中期（17 天）和后期（35 天）评估酵母物种多样性。分析显示，由 10 个属和 17 个种组成的生物多样性范围相对较宽。在所有处理中，酵母是与乳酸细菌一起参与发酵的主要微生物，这些细菌在整个过程中共存。在发酵开始时，Metschnikowia pulcherrima 是主要的酵母物种，其次是 Debaryomyces hansenii 和 Aureobasidium pullulans。随着发酵的进行，物种异质性发生变化，Pichia membranifaciens 和 Pichia anomala 演变为橄榄加工的主要酵母，在发酵的 17 天和 35 天占主导地位。分子技术允许鉴定出五种酵母，即 A. pullulans、Candida sp.、Candida silvae、Cystofilobasidium capitatum 和 M. pulcherrima，这些酵母以前未在黑橄榄发酵中报道过。
通过使用分子技术，从 Conservolea 黑橄榄发酵中鉴定出丰富的酵母群落。首次报道 Metschnikowia pulcherrima 在发酵开始时主导不同的盐水，而 Pichia anomala 和 P. membranifaciens 在发酵过程中进化。添加葡萄糖和/或乳酸会干扰发酵过程中的酵母演替和优势。
酵母在黑橄榄发酵中具有重要作用，有助于形成最终产品的感官特征。同时，某些物种会导致显著的变质。本研究增加了对存在于橄榄发酵中的酵母群落的更好了解，有助于实现更好的控制过程，减少产品损失。
