Ventimiglia Giusi, Alfonzo Antonio, Galluzzo Paola, Corona Onofrio, Francesca Nicola, Caracappa Santo, Moschetti Giancarlo, Settanni Luca
Dipartimento Scienze Agrarie e Forestali, Università degli Studi di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy.
Istituto Zooprofilattico Sperimentale della Sicilia "A. Mirri", Via G. Marinuzzi 4, Palermo, Italy.
Food Microbiol. 2015 Oct;51:57-68. doi: 10.1016/j.fm.2015.04.011. Epub 2015 May 7.
Fifteen sourdoughs produced in western Sicily (southern Italy) were analysed by classical methods for their chemico-physical characteristics and the levels of lactic acid bacteria (LAB). pH and total titratable acidity (TTA) were mostly in the range commonly reported for similar products produced in Italy, but the fermentation quotient (FQ) of the majority of samples was above 4.0, due to the low concentration of acetic acid estimated by high performance liquid chromatography (HPLC). Specific counts of LAB showed levels higher than 10(8) CFU g(-1) for many samples. The colonies representing various morphologies were isolated and, after the differentiation based on phenotypic characteristics, divided into 10 groups. The most numerous group was composed of facultative heterofermentative isolates, indicating a relevance of this bacterial group during fermentation. The genetic analysis by randomly amplified polymorphic DNA (RAPD)-PCR, 16S rRNA gene sequencing and species-specific PCRs identified 33 strains as Lactobacillus plantarum, Lactobacillus curvatus and Lactobacillus graminis. Due to the consistent presence of L. plantarum, it was concluded that this species codominates with obligate heterofermentative LAB in sourdough production in this geographical area. In order to evaluate the performances at the basis of their fitness, the 29 L. plantarum strains were investigated for several technological traits. Twelve cultures showed good acidifying abilities in vitro and L. plantarum PON100148 produced the highest concentrations of organic acids. Eleven strains were positive for extracellular protease activity. Bacteriocin-like inhibitory substances (BLIS) production and antifungal activity was scored positive for several strains, included L. plantarum PON100148 which was selected as starter for experimental sourdough production. The characteristics of the sourdoughs and the resulting breads indicated that the best productions were obtained in presence of L. plantarum PON100148.
对产自意大利南部西西里岛西部的15种酸面团进行了经典方法分析，以测定其化学物理特性和乳酸菌（LAB）水平。pH值和总可滴定酸度（TTA）大多在意大利生产的类似产品通常报告的范围内，但由于高效液相色谱法（HPLC）估计的乙酸浓度较低，大多数样品的发酵商（FQ）高于4.0。许多样品的LAB特定计数显示水平高于10(8) CFU g(-1)。分离出代表各种形态的菌落，根据表型特征进行区分后，分为10组。数量最多的一组由兼性异发酵分离株组成，表明该细菌群在发酵过程中具有相关性。通过随机扩增多态性DNA（RAPD）-PCR、16S rRNA基因测序和物种特异性PCR进行的遗传分析确定了33株植物乳杆菌、弯曲乳杆菌和禾本科乳杆菌。由于植物乳杆菌的持续存在，得出结论，在该地理区域的酸面团生产中，该物种与专性异发酵LAB共同占主导地位。为了根据其适应性评估性能，对29株植物乳杆菌菌株的几种技术特性进行了研究。12种培养物在体外显示出良好的酸化能力，植物乳杆菌PON100148产生的有机酸浓度最高。11株菌株的细胞外蛋白酶活性呈阳性。几种菌株，包括被选为实验性酸面团生产起始菌株的植物乳杆菌PON100148，对细菌素样抑制物质（BLIS）的产生和抗真菌活性评分呈阳性。酸面团及其制成面包的特性表明，在植物乳杆菌PON100148存在的情况下获得了最佳生产效果。
