Schoina Vasiliki, Terpou Antonia, Angelika-Ioanna Gialleli, Koutinas Athanasios, Kanellaki Maria, Bosnea Loulouda
Department of Chemistry, Food Biotechnology Group, University of Patras, Patras, Greece.
J Food Sci Technol. 2015 Sep;52(9):5700-8. doi: 10.1007/s13197-014-1627-9. Epub 2014 Nov 14.
Resin from Pistacia terebinthus tree was used for the immobilization of L. casei ATCC 393 cells. The encapsulated L. casei cells biocatalysts were added as adjuncts during yogurt production at 45 °C and probiotic viability was assessed during storage at 4 °C. For comparison reasons yogurt with free L. casei cells were prepared. The effect of encapsulated bacteria as adjuncts in yogurt on pH, lactic acid, lactose and other physicochemical parameters were studied for 60 storage days at 4 °C. Samples were also tested for the microbiological and organoleptic characteristics during storage at 4 °C. Encapsulation matrix seems to sustain the viability of embedded L. casei cells at levels more than 7 logcfug(-1) after 60 days of storage at 4 °C. Furthermore, the absence of pathogens such as Salmonella, Staphylococci, Enterobacteriaceae and coliforms in the produced yogurts is noteworthy where spoilage microorganisms such as yeasts and molds seem to affect yogurt quality only in absence of Pistacia terebinthus resin. The effect of the resin on production of aroma-related compounds responsible for yogurt flavor was also studied using the solid phase microextraction gas chromatography/mass spectrometry technique. Alpha and beta- pinene were the major aroma compounds detected in produced yogurts (over 60 % of total aromatic compounds detected). Yogurts with immobilized cells on P.terebintus resin had a fine aroma and taste characteristic of the resin.
乳香黄连木树的树脂被用于固定干酪乳杆菌ATCC 393细胞。在45°C的酸奶生产过程中添加包封的干酪乳杆菌细胞生物催化剂，并在4°C储存期间评估益生菌的活力。为了进行比较，制备了含有游离干酪乳杆菌细胞的酸奶。研究了包封细菌作为酸奶添加剂在4°C下储存60天对pH值、乳酸、乳糖和其他理化参数的影响。还对4°C储存期间的样品进行了微生物学和感官特性测试。在4°C储存60天后，包封基质似乎能使包埋的干酪乳杆菌细胞的活力维持在7 logcfu g(-1)以上。此外，所生产的酸奶中不存在沙门氏菌、葡萄球菌、肠杆菌科和大肠菌群等病原体值得注意，而酵母和霉菌等腐败微生物似乎仅在没有乳香黄连木树脂的情况下才会影响酸奶质量。还使用固相微萃取气相色谱/质谱技术研究了树脂对负责酸奶风味的香气相关化合物产生的影响。α-蒎烯和β-蒎烯是所生产酸奶中检测到的主要香气化合物（占检测到的总芳香化合物的60%以上）。用乳香黄连木树脂固定细胞的酸奶具有该树脂特有的良好香气和味道特征。
