On The Possibility to Trace Frozen Curd in Buffalo Mozzarella Cheese

Abstract

The manufacturing of Buffalo Mozzarella PDO (Protected Designation of Origin) cheese requires the exclusive use of fresh buffalo milk, which must be transformed into cheese within 60 hours after milking. The limited availability of buffalo milk and simultaneous increase in Mozzarella demand during the summer cause producers to use frozen intermediates (milk and/or curd) in the cheese-making process. These practices are not allowed. Few data are available in the literature about the effects of freezing on buffalo milk and curd. Recent studies demonstrated that the use of frozen buffalo milk can be detected in mozzarella cheese based on the increase in casein fragment γ4-CN. This work aims to verify the possibility of tracing the presence of frozen curd in Buffalo Mozzarella PDO cheese. The electrophoresis technique was used to reveal the presence of γ4-CN. Equivalent concentrations of this fragment were found in fresh and frozen curd that were stored for 9 months. Our results suggest that γ4-CN cannot be used to discriminate fresh PDO Mozzarella and Mozzarella cheese produced from frozen curd. A second objective of the work was to evaluate the effects of freezing on curd lipids. In particular, the fatty acid and mono-diglyceride profiles were evaluated. Significant differences were found in the amounts of 1,2-Dipalmitin and 1,3-Diolein between fresh curd and curd that was stored for 9 months at freezing temperatures. Although some significant differences were found in the mono-diglyceride profiles, no objective marker that can distinguish between fresh and frozen products is currently available.

Chemical Characteristics and Oxidative Stability of Buffalo Mozzarella Cheese Produced with Fresh and Frozen Curd

“…There is little data on the effects of using frozen curd in the production of buffalo Mozzarella cheese. According to Manzo [ 26 ], the addition of higher FC levels to the fresh curd had a depressing effect on the moisture and fat content of buffalo Mozzarella cheese. In samples containing 40% FC, the fat/protein ratio reported by Manzo [ 26 ] was 0.96, while it was 1.39 in our 50% FC samples.…”

“…According to Manzo [ 26 ], the addition of higher FC levels to the fresh curd had a depressing effect on the moisture and fat content of buffalo Mozzarella cheese. In samples containing 40% FC, the fat/protein ratio reported by Manzo [ 26 ] was 0.96, while it was 1.39 in our 50% FC samples. The fat/dry matter ratio of Mozzarella cheese with 40% FC reported by Manzo [ 26 ] was also very low (47.3%), far below the minimum threshold of 52%.…”

“…Recently, a study on buffalo Mozzarella cheese produced with the addition of frozen curd was carried out, with the final purpose to evaluate the possibility to trace frozen milk or curd in buffalo Mozzarella PDO cheese [ 26 , 27 ], but there are no studies focused on oxidative modifications due to frozen curd addition. In fact, the freezing can induce chemical modifications as lipid and protein oxidation or degradation of antioxidant molecules [ 28 ].…”

Spotting Frozen Curd in PDO Buffalo Mozzarella Cheese Through Insights on Its Supramolecular Structure Acquired by 1H TD-NMR Relaxation Experiments

“…The fragment 69-209 of beta-casein, deriving from the hydrolysis of β casein by plasmin, also called γ4-CN, was reported by some authors [5] as marker of frozen milk and curd in buffalo mozzarella cheese with Protected Designation of Origin (PDO). However, further studies did not confirm these findings [6].…”

“…10/05/1993). However, due to the scarcity of buffalo milk supply during certain years, some producers freeze part of the fresh curd produced during periods of abundance of raw material, to be used when needed in mixtures of fresh and frozen curd [6]. This is a fraudulent practice, deceptive for the consumer and representing a form of unfair competition and a damage to the product brand as well.…”