Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina; Dpto. de Ingeniería Química y en Alimentos, Facultad de Ingeniería, UNMDP, Argentina.
Int J Food Microbiol. 2018 Dec 2;286:179-189. doi: 10.1016/j.ijfoodmicro.2018.08.013. Epub 2018 Aug 16.
The halophilic microbial community of the salted-ripened anchovy process was studied. Samples from raw materials (salt and fresh anchovies) and from the stages of brining and ripening were collected and analyzed for their bacterial counts at 15 and 20% NaCl. No halophilic colonies were found in fresh anchovy and counts of about 10 CFU/g were determined in salt samples. A fluctuation of bacterial counts during the process was found. At the end of brining, ~10 CFU/g were determined in anchovy samples and this value was reduced to not detectable counts at the beginning of the ripening stage. After one month, counts increased to ~10 CFU/g and remained stable until the end of the process. From each sample, colonies having different morphotypes were isolated and submitted to a macro and microscopic characterization, a study of salt requirement for growth, and biochemical and phenotypic tests. The results were submitted to Univariate, Bivariate and Multiple Correspondence Factorial Analysis (MCFA). A total of 79 colonies were isolated during the salting-ripening anchovy process. Among the isolates, about 40-50% was positive for indole production and lipolytic activity and a 25% showed ability to produce HS and proteolytic capacity. Proteolytic and lipolytic activities were well balanced along the process and resulted independent from the isolation stage, which is a desirable condition due to the contribution of microbial proteolysis and lipolysis to the development of texture and final aroma, respectively. HS and indole producers practically were not detected during ripening. This fact is important because indole and HS are associated with the development of off-flavors and spoilage in salted fish products. MFCA and Cluster Analyses complemented the Bivariate Analyses. The factor map showed proximity between the isolates from salt samples and from ripening. Isolates were statistically clustered in two groups. Cluster 1 grouped non-desirable activities (HS and indole production) with cultures proceeding from brining whereas Cluster 2 related isolates mainly from salt samples and during ripening with some desirable microbial capacities (Cytochrome oxidase activity and non-HS and non-indole production). These results would indicate that during the ripening process of salted anchovies, a natural selection of beneficial microorganisms for the development of the typical product sensory attributes occurred.
对腌制凤尾鱼过程中的嗜盐微生物群落进行了研究。采集了原料（盐和新鲜凤尾鱼）以及腌制和成熟阶段的样品，并在 15%和 20%NaCl 下分析了细菌计数。在新鲜凤尾鱼中未发现嗜盐菌，盐样中的计数约为 10 CFU/g。在整个过程中发现了细菌计数的波动。在腌制结束时，凤尾鱼样品中的计数约为 10 CFU/g，在成熟阶段开始时减少到无法检测到的计数。一个月后，计数增加到约 10 CFU/g，并在整个过程中保持稳定。从每个样品中分离出具有不同形态的菌落，并进行宏观和微观特征描述、生长盐度要求研究、生化和表型测试。结果提交给单变量、双变量和多元对应因子分析 (MCFA)。在腌制凤尾鱼过程中总共分离出 79 株菌落。在分离株中，约有 40-50% 产吲哚和脂解活性阳性，25% 具有产 HS 和蛋白水解能力。整个过程中蛋白水解和脂解活性平衡良好，且与分离阶段无关，这是一种理想的条件，因为微生物蛋白水解和脂解分别有助于质地和最终香气的发展。在成熟过程中几乎没有检测到 HS 和吲哚的产生。这一事实很重要，因为吲哚和 HS 与腌制鱼产品中异味和变质的发展有关。MFCA 和聚类分析补充了双变量分析。因子图显示了盐样和成熟样分离株之间的接近程度。分离株在统计学上分为两组。簇 1 将非期望活性（HS 和吲哚产生）与从腌制开始的培养物聚集在一起，而簇 2 将主要来自盐样和成熟过程中的分离株与一些期望的微生物能力（细胞色素氧化酶活性和非 HS 和非吲哚产生）联系起来。这些结果表明，在腌制凤尾鱼的成熟过程中，对发展典型产品感官特性有益的微生物发生了自然选择。
