Impact of post fermentation cooling patterns on fatty acid profile, lipid oxidation and antioxidant features of cow and buffalo milk set yoghurt
Impact of post fermentation cooling patterns on fatty acid profile, lipid oxidation and antioxidant features of cow and buffalo milk set yoghurt
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DOI：
10.1186/s12944-020-01263-1
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发表时间：
2020-04-15
影响因子：
4.5
通讯作者：
Khalique, Anjum
中科院分区：
文献类型：
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作者：
Khan, Imran Taj;Nadeem, Muhammad;Khalique, Anjum
背景在凝固型酸奶的制造中，在达到4.6 pH后，应用发酵后冷却以停止细菌活性。根据所需的质地和风味属性，相应地选择单相和两相冷却模式。在一个阶段冷却中，使用急速冷冻将酸奶的温度迅速降低到10 ℃以下，然后逐渐降低到4-5 ℃。在两阶段冷却中，酸奶的温度迅速降至20摄氏度以下，然后逐渐降至4-5摄氏度。这些冷却阶段对酸奶的质构和风味前景具有显著影响。研究不同冷却方式对牛乳和布法罗乳凝固型酸奶的脂肪酸组成、抗氧化特性、脂质氧化和感官特性的影响是十分必要的。方法采用完全随机设计，每个处理重复5次，以减少变异。使用嗜热链球菌和保加利亚乳杆菌作为发酵剂细菌，将未经任何标准化的全牛和布法罗乳转化为凝固型酸奶（400 g杯）。在达到4.6 pH值后，将奶牛和布法罗酸奶样品暴露于三种不同的冷却模式。在第一次试验中，将奶牛和布法罗酸奶样品在1小时内从43 ℃冷却至25 ℃，最后在另一小时内冷却至4-5 ℃（T-1）。在第二次试验中，样品在1小时内从43摄氏度冷却到18摄氏度，最后在另一个1小时内冷却到4-5摄氏度。（T-2）。在第三次试验中，样品在2小时内从43摄氏度冷却到4-5摄氏度（T-1）。以10天为一周期，连续20天对奶牛和布法罗酸奶样品的脂肪酸谱、总抗氧化能力、还原力、游离脂肪酸、过氧化值、共轭二烯、维生素A、E、颜色和风味进行评价。结果3种冷却方式对酸奶的成分特性无显著影响。布法罗酸奶的脂肪、蛋白质和总固形物含量显著高于牛乳酸奶（p < 0.05）。0 d时，T-2和T-3的DPPH自由基清除活性显著高于T-1。这可能是由于T-1比T-2和T-3在相对较高的温度下暴露时间更长。在T-2和T-3中，储存期长达10天的影响不显著。牛奶和布法罗酸奶的还原力也受到冷却方式的显著影响。T-2和T-3的还原力显著高于T-1（p < 0.05）。在第0天时，T-3组奶牛和布法罗酸奶的总抗氧化能力分别为42.6%和61.4%。0天时，T-2和T-3的总抗氧化能力显著高于T-1。贮藏对T-2和T-3的总抗氧化能力的影响在贮藏10天前不显著。在第0天，冷却模式对T-1、T-2和T-3的脂肪酸谱的影响不显著，而储存时间对脂肪酸谱有显著影响。在T-1中贮存10 d后，C-4：0、C-6：0、C-8：0、C-10：0、C-12：0、C-14：0、C-16：0、C-18：0、C-18：1和C-18：2的含量分别下降了0.1、0.11、0.09、0.07、0.21、0.38、0.28、0.27、0.44和0.06%。T-1酸奶中C-4：0、C-6：0、C-8：0、C-10：0、C-12：0、C-14：0、C-16：0、C-18：0、C-18：1和C-18：2的浓度分别下降了0.07、0.15、0.04、0.17、0.20、0.34、0.27、0.36和0.04%。在T-2和T-3中储存10天后，从C-4：0到C-10：0，脂肪酸损失分别为1.2%和3.61%。牛奶类型对酸奶的过氧化值没有影响。将牛奶和布法罗酸奶从43摄氏度冷却到25摄氏度对过氧化值有明显的影响。在第0天，T-1组的奶牛和布法罗酸奶的过氧化值分别为0.32和0.33（MeqO（2）/kg）。第0天，T-2组奶牛和布法罗酸奶的过氧化值分别为0.24和0.26（MeqO（2）/kg）。第0天，T-3组奶牛和布法罗酸奶的过氧化值分别为0.23和0.25（MeqO（2）/kg）。冷却模式，即从43摄氏度到25，18和5摄氏度（T-1，T-2和T-3）对维生素A和E的量有显着影响。维生素A和E的浓度在T-1中显著低于T-2和T-3。冷却方式对质地有显著影响，与T-2和T-3相比，T-1具有更厚的质地和更高的粘度。贮藏10 d后，酸奶的粘稠度为T-1 > T-2 > T-3，颜色和风味评分无差异。结论牛奶类型和发酵后冷却方式对酸奶的抗氧化特性、脂肪酸组成、脂质氧化和质构特性有显著影响。布法罗乳酸奶具有较高的脂肪、蛋白质、抗氧化能力和维生素含量。T-1的抗氧化性和感官特性在贮藏10天内最佳。
Background In the manufacturing of set yoghurt, after reaching 4.6 pH, post fermentation cooling is applied to stop the bacterial activity. Depending upon the required textural and flavor attributes, one phase and two phase cooling patterns are accordingly selected. In one phase cooling, temperature of the yoghurt is rapidly decreased below 10 degrees C using blast freezing and then it is gradually dropped to 4-5 degrees C. In two phase cooling, temperature of yogurt is rapidly decreased to less than 20 degrees C and then it is gradually decreased to 4-5 degrees C. These cooling phases have a significant impact on textural and flavor perspectives of yoghurt. It is necessary to study the impact of industrially adopted cooling patterns on fatty acid profile, antioxidant characteristics, lipid oxidation and sensory characteristics of cow and buffalo milk set yoghurt. Methods This experiment was organized in a completely randomized design and every treatment was replicated five times to minimize the variation. Whole cow and buffalo milk without any standardization were converted to set yoghurt (400 g cups) using Strepotococcus thermophillus and Lactobacillus bulgaricus as starter bacteria. After reaching 4.6 pH, cow and buffalo yoghurt samples were exposed to three different cooling patterns. In first trial, samples of cow and buffalo yoghurt were cooled from 43 degrees C to 25 degrees C in 1 h and finally cooled to 4-5 degrees C in another hr. (T-1). In second trial, samples were cooled from 43 degrees C to 18 degrees C in 1 hr. and finally cooled down to 4-5 degrees C in another 1 h. (T-2). In third trial, samples were cooled from 43 degrees C to 4-5 degrees C in 2 h (T-1). Alteration in fatty acid profile, total antioxidant capacity, reducing power, free fatty acids, peroxide value, conjugated dienes, vitamin A, E, color and flavor of cow and buffalo yoghurt samples were assessed for 20 days at the frequency of 10 days. Results All the three cooling patterns had a non-significant effect on compositional attributes of yoghurt. Buffalo milk yogurt had higher percentage of fat, protein and total solids than yoghurt prepared from cow milk (p < 0.05). At zero day, DPPH free radical scavenging activity of T-2 and T-3 was significantly higher than T-1. This may be due to the longer exposure of T-1 at relatively higher temperature than T-2 and T-3. Effect of storage period up to 10 days was non-significant in T-2 and T-3. Reducing power of cow and buffalo milk yoghurt was also significantly affected by the cooling patterns applied. Reducing power of T-2 and T-3 was considerably higher than T-1 (p < 0.05). At zero-day, total antioxidant capacity of cow and buffalo milk yoghurt in T-3 was 42.6 and 61.4%, respectively. At zero day, total antioxidant capacity of T-2 and T-3 was significantly higher than T-1. Effect of storage on total antioxidant capacity of T-2 and T-3 remained non-significant till 10 days of storage. At zero day, the impact of cooling patterns on fatty acid profile of T-1, T-2 and T-3 was non-significant, whereas, storage period had a marked impact on fatty acid profile. After 10 days, T-1 was considerably different in fatty acids from T-2 and T-3.After 10 days of storage of cow milk yoghurt in T-1, concentration of C-4:0, C-6:0, C-8:0, C-10:0, C-12:0, C-14:0, C-16:0, C-18:0, C-18:1 and C-18:2 decreased by 0.1, 0.11, 0.09, 0.07, 0.21, 0.38, 0.28, 0.27, 0.44 and 0.06%, respectively. Cow milk yoghurt in T-1 after 10 days of storage, concentration of C-4:0, C-6:0, C-8:0, C-10:0, C-12:0, C-14:0, C-16:0, C-18:0, C-18:1 and C-18:2 decreased by 0.07, 0.15, 0.04, 0.17, 0.20, 0.34, 0.27, 0.36 and 0.04%, respectively. After 10 days of storage in T-2 and T-3, loss of fatty acids was 1.2 and 3.61% from C-4:0 to C-10:0, respectively. Milk type had no effect on peroxide value of yoghurt. Cooling of cow and buffalo yoghurt from 43 degrees C to 25 degrees C had a pronounced effect on peroxide value. At zero day, peroxide values of cow and buffalo yoghurt in T-1 were 0.32 and 0.33 (MeqO(2)/kg). At zero day, peroxide value of cow and buffalo yoghurt in T-2 were 0.24 and 0.26 (MeqO(2)/kg). At zero day, peroxide value cow and buffalo yoghurt in T-3 were 0.23 and 0.25 (MeqO(2)/kg). Cooling patterns i.e. from 43 degrees C to 25, 18 and 5 degrees C (T-1, T-2 and T-3) had a significant effect on the amount of vitamin A and E. Concentration of vitamin A and E in T-1 were significantly less than T-2 and T-3. Cooling patterns had a significant effect on texture, T-1 had a thick texture with higher viscosity as compared to T-2 and T-3. Thickness of yoghurt was in the order of T-1 > T-2 > T-3 with no difference in color and flavor score till 10 days of storage. Conclusion Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T-1 were optimum till 10 days of storage.