I Ingredients for Dairy Products Manufacturing
Milk Quality and Processing
Germano Mucchetti1 and Angelo V. Zambrini2
- 1 Dipartimento di Scienze degliAlimenti e delFarmaco, Parco Area delle Scienze, Parma, Italy
- 2 Institute for Management Research, Nijmegen School of Management, Radboud University, Nijmegen, The Netherlands
Milk composition is the result of breeding and feeding conditions. The traditional goal of milk producers is the highest yield of milk with the highest amount of protein and fat. The aim of milk processors is to have milk with differentiated composition able to provide nutritional and sensorial quality specific for each milk product (fluid milk, fermented milk, cheese, dried milk or milk ingredients) so as to increase the quality of the products and the efficiency of the processes.
The interest of milk producers may be sometimes in conflict with milk processors, despite the evidence that the supply chain needs a suitable milk to efficiently make a valuable milk product, to be recognized as such by consumers, willing to pay the right price for this reason.
It is first important to define milk protein, internationally considered as the product of total nitrogen by 6.38. IDF (1995) discussed if this definition should discount either the fraction called “nonprotein nitrogen” or the urea fraction, reducing the declared protein for milk and many milk products by 5% or 2.5%. Such a change could have significant implications with respect to payment to milk producers, animal breeding records, nutrition labeling, and the position of dairy products against competitive products such as soya.
The definition of milk protein may also divide the milk industry as the target protein, for most of cheese producers is casein, while for fluid or dried milk producers the values is the total protein content, as this is the content regulated by legal and nutritional issues.
Furthermore, the quality of proteins may be important as nutritional and well-being viewpoints are taken into account.
The method of evaluating the dietary quality of protein in human nutrition could change in the near future, as FAO is advocating the replacement of PDCAAS (Protein Digestibility Corrected Amino Acid Score) with the DIAAS (Digestible Indispensable Amino Acid Score). DIAAS measures the oro-ileal nitrogen balance by calculating the ileal digestibility of individual amino acids. In contrast, PDCAAS uses crude faecal digestibility values in measuring the oro-faecal nitrogen balance, which includes contributions from intestinal secretions and colonic bacteria, thus underestimating the protein available for absorption (FAO, 2014). The use of DIAAS would change the
Advances in Dairy Products, First Edition.
Edited by Francesco Conto, Matteo A. Del Nobile, Michele Faccia, Angelo V. Zambrini, and Amalia Conte. © 2018 John Wiley & Sons Ltd. Published 2018 by John Wiley & Sons Ltd.
ranking of the protein quality, determining a higher value of milk proteins when compared with other protein sources (Rutherfurd et al., 2015).
The protein content and a better score of the nutritional quality of milk proteins contribute to add value to milk products compared to other food proteins and as a direct consequence to add value to milk. So, today protein content is the first component of milk quality, determining its economic value.