Abstract：
To meet the high consumer demand, butter production has increased over the last few years. As a result, the buttermilk (BM) co-produced volumes require new ways of adding value, such as in cheese manufacturing. However, BM use in cheese milk negatively influences the cheesemaking process (e.g., altered coagulation properties) and the product\'s final quality (e.g., high moisture content). The concentration of BM by ultrafiltration (UF) could potentially facilitate its use in cheese manufacturing through an increased protein content while maintaining the milk salt balance. Simultaneously, little is known about the digestion of UF BM cheese. Therefore, this study aimed to characterize the impact of UF BM on cheese manufacture, its structure, and its behavior during in vitro digestion. A 2-fold UF concentrated BM was used for cheese manufacture (skim milk [SM] - control). Compositional, textural, and microstructural analyses of cheeses were first conducted. In a second step, the cheeses were fed into an in vitro TNO gastrointestinal digestion model (TIM-1) of the stomach and small intestine and protein and phospholipid (PL) bioaccessibility was studied. The results showed that UF BM cheese significantly differed from SM cheese regarding its composition, hardness (p < 0.05) and microstructure. However, in TIM-1, UF BM and SM cheeses showed similar digestion behavior as a percentage of protein and PL intake. Despite relatively more non-digested and non-absorbed PL in the ileum efflux of UF BM cheese, the initially higher PL concentration contributes to an enhanced nutritional value compared to SM cheese. To our knowledge, this study is the first to compare the bioaccessibility of proteins and PL from UF BM and SM cheeses.
摘要：
为了满足消费者的高需求，在过去的几年里，黄油的产量有所增加。因此,酪乳(BM)共同生产的卷需要新的增值方式，例如在奶酪制造中。然而,奶酪牛奶中的BM使用会对奶酪制作过程产生负面影响(例如，改变的凝固特性)和产品的最终质量(例如，高水分含量)。通过超滤（UF）浓缩BM可能会通过增加蛋白质含量同时保持乳盐平衡来促进其在奶酪生产中的使用。同时,对UFBM奶酪的消化知之甚少。因此,本研究旨在表征UFBM对奶酪生产的影响，其结构,及其在体外消化过程中的行为。将2倍UF浓缩的BM用于干酪制造(脱脂乳[SM]-对照)。组成,纹理，首先对奶酪进行了微观结构分析。第二步,将奶酪喂入胃和小肠的体外TNO胃肠道消化模型（TIM-1），并研究了蛋白质和磷脂（PL）的生物可及性。结果表明，UFBM干酪与SM干酪的成分明显不同，硬度(p<0.05)和微观结构。然而,在TIM-1中，UFBM和SM奶酪显示出类似的消化行为，占蛋白质和PL摄入量的百分比。尽管UFBM奶酪的回肠外排中相对较多的非消化和非吸收PL，与SM奶酪相比，最初较高的PL浓度有助于提高营养价值。据我们所知,这项研究是第一个比较UFBM和SM奶酪中蛋白质和PL的生物可及性的研究。
