Mani-López E, Palou E, López-Malo A
Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, Cholula, Puebla 72810, México.
Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, Cholula, Puebla 72810, México.
J Dairy Sci. 2014 May;97(5):2578-90. doi: 10.3168/jds.2013-7551.
Currently, the food industry wants to expand the range of probiotic yogurts but each probiotic bacteria offers different and specific health benefits. Little information exists on the influence of probiotic strains on physicochemical properties and sensory characteristics of yogurts and fermented milks. Six probiotic yogurts or fermented milks and 1 control yogurt were prepared, and we evaluated several physicochemical properties (pH, titratable acidity, texture, color, and syneresis), microbial viability of starter cultures (Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) and probiotics (Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus reuteri) during fermentation and storage (35 d at 5°C), as well as sensory preference among them. Decreases in pH (0.17 to 0.50 units) and increases in titratable acidity (0.09 to 0.29%) were observed during storage. Only the yogurt with S. thermophilus, L. delbrueckii ssp. bulgaricus, and L. reuteri differed in firmness. No differences in adhesiveness were determined among the tested yogurts, fermented milks, and the control. Syneresis was in the range of 45 to 58%. No changes in color during storage were observed and no color differences were detected among the evaluated fermented milk products. Counts of S. thermophilus decreased from 1.8 to 3.5 log during storage. Counts of L. delbrueckii ssp. bulgaricus also decreased in probiotic yogurts and varied from 30 to 50% of initial population. Probiotic bacteria also lost viability throughout storage, although the 3 probiotic fermented milks maintained counts ≥ 10(7)cfu/mL for 3 wk. Probiotic bacteria had variable viability in yogurts, maintaining counts of L. acidophilus ≥ 10(7) cfu/mL for 35 d, of L. casei for 7d, and of L. reuteri for 14 d. We found no significant sensory preference among the 6 probiotic yogurts and fermented milks or the control. However, the yogurt and fermented milk made with L. casei were better accepted. This study presents relevant information on physicochemical, sensory, and microbial properties of probiotic yogurts and fermented milks, which could guide the dairy industry in developing new probiotic products.
目前，食品行业希望扩大益生菌酸奶的种类，但每种益生菌都具有不同的特定健康益处。关于益生菌菌株对酸奶和发酵乳的物理化学性质及感官特性的影响，相关信息较少。我们制备了六种益生菌酸奶或发酵乳以及一种对照酸奶，并评估了几种物理化学性质（pH值、可滴定酸度、质地、颜色和乳清渗出）、发酵剂培养物（德氏乳杆菌保加利亚亚种和嗜热链球菌）和益生菌（嗜酸乳杆菌、干酪乳杆菌和罗伊氏乳杆菌）在发酵和储存（5℃下35天）期间的微生物活力，以及它们之间的感官偏好。储存期间观察到pH值下降（0.17至0.50个单位）和可滴定酸度增加（0.09至0.29%）。只有含有嗜热链球菌、德氏乳杆菌保加利亚亚种和罗伊氏乳杆菌的酸奶在硬度上有所不同。在所测试的酸奶、发酵乳和对照之间，未确定粘附性存在差异。乳清渗出率在45%至58%之间。储存期间未观察到颜色变化，在所评估的发酵乳制品之间也未检测到颜色差异。嗜热链球菌的数量在储存期间从1.8降至3.5个对数。德氏乳杆菌保加利亚亚种的数量在益生菌酸奶中也有所下降，占初始菌数的30%至50%。益生菌在整个储存过程中也丧失了活力，不过三种益生菌发酵乳在3周内保持菌数≥10⁷cfu/mL。益生菌在酸奶中的活力各不相同，嗜酸乳杆菌的菌数在35天内保持≥10⁷cfu/mL，干酪乳杆菌保持7天，罗伊氏乳杆菌保持14天。我们发现在六种益生菌酸奶、发酵乳或对照之间没有显著的感官偏好。然而，用干酪乳杆菌制作的酸奶和发酵乳更受青睐。本研究提供了关于益生菌酸奶和发酵乳的物理化学、感官和微生物特性的相关信息，可为乳制品行业开发新的益生菌产品提供指导。
