Laboratoire d'Écologie et de Technologie Microbienne, Institut National des Sciences, Appliquées et de Technologie (INSAT), University of Carthage, 1080 Tunis, Tunisia.
Department of Soil, Plant and Food Science, University of Bari Aldo Moro, 70126 Bari, Italy.
Int J Food Microbiol. 2016 May 16;225:9-19. doi: 10.1016/j.ijfoodmicro.2016.03.004. Epub 2016 Mar 5.
Wheat bread is the most popular staple food consumed in Tunisia and, despite the niche production of some typical breads (e.g. Tabouna, Mlawi, Mtabga), the major part is currently produced with baker's yeast at industrial or, mainly, at artisanal level, while the use of sourdough fermentation is rarely reported. Considering the growing national demand for cereal baked goods, it can be hypothesized that sourdough fermentation through the use of selected lactic acid bacteria as starters could improve the overall quality and the diversification of local products. Different cereal grains were collected from the regions of Ariana, Bizerta, Beja Nabeul, and Seliana, and the autochthonous lactic acid bacteria were isolated, identified, characterized and selected on the basis of the kinetics of acidification, the proteolytic activity, and the quotient of fermentation. Lactobacillus curvatus MA2, Pediococcus pentosaceus OA2, and Pediococcus acidilactici O1A1 were used together as mixed starter to obtain a selected sourdough. According to the backslopping procedure, a type I sourdough was made from a Tunisian flour (spontaneous sourdough). Compared to the use of the spontaneous sourdough, the one obtained with selected and mixed starters by a unique fermentation step, favored the increase of the concentrations of organic acids, phenols, and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities, that increased ca. 20% compared to the control. Moreover, the selected starters improved the in vitro protein digestibility (ca. 82% when selected sourdough was used), textural and sensory features of the breads, as determined by textural profile analysis and panel test, respectively. This study aimed at exploiting the potential of selected autochthonous lactic acid bacteria and extending the use of a sourdough (type II), thanks to the set-up of a two-step fermentation protocol designed for application at the industrial level, and the confirmed nutritional, textural, and sensory advantages of the final product.
小麦面包是突尼斯最受欢迎的主食，尽管一些典型面包（例如 Tabouna、Mlawi、Mtabga）的产量较小，但目前主要在工业或主要在手工水平上使用商业酵母生产，而很少有报道使用酸面团发酵。考虑到国内对谷物烘焙食品的需求不断增长，可以假设通过使用选定的乳酸菌作为发酵剂进行酸面团发酵可以提高产品的整体质量和多样化。从阿里亚纳、比塞大、贝贾努布尔和塞利阿纳地区收集了不同的谷物，并根据酸化动力学、蛋白水解活性和发酵商对土著乳酸菌进行了分离、鉴定、特性分析和选择。将乳杆菌 MA2、戊糖片球菌 OA2 和嗜酸乳杆菌 O1A1 一起用作混合发酵剂，以获得选定的酸面团。根据回种程序，用一种突尼斯面粉（自发酸面团）制作了 I 型酸面团。与使用自发酸面团相比，通过独特的发酵步骤使用选定的和混合发酵剂获得的酸面团，有利于增加有机酸、酚类和总游离氨基酸的浓度、最适宜的发酵商和最强烈的植酸酶和抗氧化活性，与对照相比增加了约 20%。此外，选定的发酵剂提高了面包的体外蛋白质消化率（使用选定的酸面团时约为 82%）、质地和感官特性，分别通过质地分析和小组测试确定。本研究旨在利用选定的土著乳酸菌的潜力，并通过建立两步发酵方案来扩展酸面团（II 型）的使用，该方案是为在工业水平上应用而设计的，并且确认了最终产品的营养、质地和感官优势。
