One key aspect of high moisture mozzarella is that it is sold immersed in its preserving liquid, which is mainly used to maintain the freshness, but it also has other technological functions. Being a chemical matrix, it tends to interact with mozzarella cheese, affecting its quality during the storage period: for this reason, it will be important to realize a well-balanced preserving liquid, considering the effects it can generate on the final product.
The preserving liquid is fundamental for three technological reasons:
- it prevents rind formation;
- it helps the formation of “skin” having a tender, smooth, shiny consistency, and a homogeneous appearance;
- eventually, it helps complete the salting process.
The preserving liquid can be considered an acidic solution obtained by the addition of citric acid or lactic acid, which can contain 1-1.5% of sodium chloride. In traditional productions, such as buffalo mozzarella cheese, the preserving liquid in some cases is still prepared by fermentation of the water used in the stretching process, aiming at increasing its acidity; the resulting liquid is then added with salt.
Aiming at the extension of the shelf-life of mozzarella immersed in this liquid, research also experimentally explored the addition of calcium lactate to brine acidified with lactic acid (Faccia et al., 2019), which showed interesting results for sensory aspects during storage. In a previous work, Faccia et al. (2013) studied the effect of calcium lactate on both the sensory and microbiological quality of Fiordilatte. Results showed a modest inhibition effect of calcium lactate on microbial growth; concerning the sensory quality, the authors recorded a certain improvement in the odour and texture. These studies give a new perspective especially for those processors who export in third countries their product and want to extend the shelf life of fresh mozzarella.
Storage in preserving liquid generates a whole series of exchanges between mozzarella cheese and liquid, which are influenced by: the composition of mozzarella cheese, in particular its moisture content, the nature of the preserving liquid, and the storage temperature (from 4 °C up to room temperature) and its duration.
Water is absorbed or released between the two matrices; moreover, soluble components (calcium, lactates, sugars or compounds derived from proteolytic activity) are released from mozzarella cheese to the preserving liquid. As a result, structural modifications occur.
These modifications generally begin with the wrinkling and consequent detachment of the “skin”. Solubilization of calcium may facilitate this process leading to further structural changes concerning the inner part of mozzarella cheese. This process has a major impact on physical and chemical properties of mozzarella cheese. The extreme consequence occurs when the inner part takes on a pasty and soft consistency similar to that of stracchino.
In addition to solubilization of calcium, hydrolysis of casein due to residual activity of proteolytic enzymes may occur. These enzymes are not completely inactivated during the stretching process. Moreover, there is a certain effect of plasmin, a hydrolytic enzyme that remains embedded in the curd and influences the maturation of mozzarella cheese. Also, starter cultures used may affect the exchanges between mozzarella and preserving liquid.
One fundamental aspect to consider and control is to have potable water available at any step of cheese making, also for the production of the preserving liquid. This means that all the best practices to avoid cross contamination must be implemented, particularly because traditional productions reuse the water used during the stretching process without heating treatment. This aspect is positive for the maintenance of lactic acid bacteria, but is risky in case of contaminating bacteria and/or pathogens.
At Alpha Solutions, we can provide expertise on the mozzarella cheese making process and the preparation of the ideal preserving liquid to help our clients meet their market needs.
Rei Mizuno, Tadahiro Abe, Hiroshi Koishihara, Teiichiro Okawa, The Effect of Preservative Liquid Composition on Physicochemical Properties of Mozzarella Cheese, Food Science and Technology Research, 2016, Volume 22, Issue 2, Pages 261-266, Released April 20, 2016, Online ISSN 1881-3984, Print ISSN 1344-6606, https://doi.org/10.3136/fstr.22.261
Germano Mucchetti, Erasmo Neviani, 2006. Microbiologia e tecnologia lattiero-casearia. Qualità e sicurezza. Tecniche nuove
Cesare Corradini, 1995. Chimica e tecnologia del latte. Tecniche nuove
- Faccia, G. Gambacorta, G. Natrella, F. Caponio, 2019. Shelf life extension of Italian mozzarella by use of calcium lactate buffered brine. Food Control Volume 100, June 2019, Pages 287-291
Faccia M., Angiolillo L., Mastromatteo M., Conte A., Del Nobile M. A., 2013. The effect of incorporating calcium lactate in the saline solution on improving the shelf life of Fiordilatte. Vol 66 International Journal of Dairy Technology. DOI: 10.1111/1471-0307.12046
Senior Technical Consultant
Alpha Solutions, Food and Ingredients