Influence of medium-concentration factor microfiltration treatment on the characteristics of low-moisture Mozzarella cheese

To study the chemical properties, the initial recovery of milk components, oiling off, and the textural properties of the cheese during a 60-day refrigerated storage period, skim milk was microfiltered through a 1.4-μm ceramic membrane to remove bacteria, and then low-moisture Mozzarella cheese was manufactured from medium-concentration factor (CF) microfiltration (MF) (0.1 μm of pore size, CF = 2.3) retentate with added cream. The changes in expressible serum (ES) were also studied. Three cheese-making trials were conducted on Mozzarella cheese milk using two different methods: MF and control. Changes in the levels of proteolysis patterns were monitored using pH 4.6-soluble nitrogen (SN), initially higher for microfiltration Mozzarella cheese (MMC) because of the higher content of caseinomacropeptide, and 12% trichloroacetic acid TCA-SN, and using SDS-PAGE. The levels of the secondary proteolysis (12% TCA-SN) were significantly higher in control Mozzarella cheese (CMC). The CMC showed a greater release of free oil at the beginning of aging time but this release was always lower than that observed for MMC. The textural characteristics (hardness, springiness, and cohesiveness) of both cheeses have significant differences, highly correlated to proteolysis indicators, during the ripening time. It is suggested that the differences in composition, proteolysis, oiling off, and textural characteristics in both the cheese and the ES attributes arise mainly as a result of the double content of calcium salts in 0.1-μm MF cheese issued from milk enriched with 2.3 times casein content. Indeed, the high content in calcium salts is known to inhibit autolysis of mesophilic lactic starter by increasing the buffering capacity of cheese aqueous phase, and then causing a slowdown of proteolysis. It likely leads to a different structuration of fat in Mozzarella cheese causing higher oiling off. The results obtained in this study show the possibility of making Mozzarella cheese from milk that has 2.3 times more micellar casein (50 g·kg), and to obtain products similar to those obtained from usual milk, adjustment of calcium salt mineralization is required. microfiltration / Mozzarella cheese / oiling off / texture profile analysis / expressible serum 摘要 – 中等浓缩因子的微滤处理对低水分 Mozzarella 干酪特性影响摘要○ 脱脂乳经 1.4 μm 的陶瓷膜除菌后,采用 0.1 μm 陶瓷膜浓缩 2.3 倍并加入稀奶油复配以生产低水分 Mozzarella 干酪,并对其 60 d 成熟期内的化学、乳成分回收、游离油析出、质构及液相等特性进 行了研究○ 两种不同的处理方式 (微滤组及对照组) 重复三次生产干酪○ 采用 pH 4.6-SN、12% TCA-SN及 SDS-PAGE研究了蛋白降解过程○ 微滤组Mozzarella干酪由于酪蛋白巨肽含量较高 而使得初级蛋白降解 (pH 4.6-SN) 高于对照组 Mozzarella 干酪,而二级蛋白降解低于对照组 *Corresponding author (通讯作者): [email protected] Dairy Sci. Technol. 89 (2009) 139–154 © INRA, EDP Sciences, 2009 DOI: 10.1051/dst/2009002 Available online at: www.dairy-journal.org