Objective: The aim was to study the influence of cooling milk at 9 degrees C at the farm versus keeping it at 20 degrees C on Parmigiano Reggiano cheese lipolysis. Methods: A total of six cheesemaking trials (3 in winter and 3 in summer) were performed. In each trial, milk was divided continuously into two identical aliquots, one of which was kept at 9 degrees C (MC9) and the other at 20 degrees C (MC20). For each trial and milk temperature, vat milk (V-milk) and the resulting 21 month ripened cheese were analysed. Results: Fat and dry matter and fat/casein ratio were lower in MC9 V-milk (p <= 0.05) than in MC20. Total bacteria, mesophilic lactic acid and psychrotrophic and lipolytic bacteria showed significant differences (p <= 0.05) between the two V-milks. Regarding cheese, fat content resulted lower and crude protein higher (p <= 0.05) both in outer (OZ) and in inner zone (IZ) of the MC9 cheese wheels. Concerning total fatty acids, the MC9 OZ had a lower concentration of butyric, capric (p <= 0.05) and medium chain fatty acids (p <= 0.05), while the MC9 IZ had lower content of butyric (p <= 0.05), caproic (p <= 0.01) and short chain fatty acids (p <= 0.05). The levels of short chain and medium chain free fatty acids (p <= 0.05) were lower and that of long chain fatty acids (p <= 0.05) was higher in MC9 OZ cheese. The principal component analysis of total and free fatty acids resulted in a clear separation among samples by seasons, whereas slight differences were observed between the two different milk tem-peratures. Conclusion: Storing milk at 9 degrees C at the herd affects the chemical composition of Parmigiano Reggiano, with repercussion on lipolysis. However, the changes are not very relevant, and since the cheese can present a high variability among the different cheese factories, such changes should be considered within the "normal variations" of Parmigiano Reggiano chemical characteristics.
Fatty acids composition and lipolysis of Parmigiano Reggiano PDO cheese: effect of the milk cooling temperature at the farm / Franceschi, Piero; Formaggioni, Paolo; Brasca, Milena; Natrella, Giuseppe; Faccia, Michele; Malacarne, Massimo; Summer, Andrea. - In: ANIMAL BIOSCIENCE. - ISSN 2765-0235. - 36:1(2023), pp. 132-143. [10.5713/ab.22.0080]