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Background: Cheese manufacturing consists of a dehydration process by which most of the whey is drained off. Whey proteins (WP) represent a nutritionally valuable fraction largely lost in the whey stream. The increasing consumer demand for food with novel texture and functionality prompted the dairy industry to exploit the valorization of WP. Scope and approach: Cheese milk is considered a vehicle for the inclusion of WP. In this review, we discuss technological tools to fortify cheese with WP. We focus on both the pioneer approaches (the heat treatment of cheese milk, membrane separation technologies and the direct addition of milk-or whey-based derivatives) and on more recent techniques such as high hydrostatic pressure, ultra-high pressure homogenization, transglutaminase treatment of cheese milk and direct addition of buttermilk. Key findings and conclusions: Milk fortification with WP influences the yield and overall properties of resulting cheeses. Processing conditions need to be adapted to successfully manufacture WP-fortified conventional cheeses as well as novel varieties (such as low-fat cheeses). As yet, only some technological tools to include WP in cheese are exploited at industrial scale. The combination of different techniques is a strategy to overcome the impairment of cheese attributes.

In a study considering 15 commercial samples of liquid milk-based infant formulas (MBF) from different manufacturers, the levels of selected molecules, that is, furosine (FUR), galactosyl-beta-pyranone (GAP), lactulose (LCT), and lysinoalanine (LAL), have been measured to provide estimation of the heat damage in these products. The ranges of the studied markers were as follows: FUR=153-600 mg 100 g(-1) of protein, GAP=0.5-4.3 mg L(-1), LCT=226-1511 mg L(-1), and LAL=1.0-16.1 mg 100 g(-1) of protein. The highest levels were found in MBF intended for the youngest babies. Experimental samples were produced in an industrial plant to evaluate the relative contribution of individual technological aspects to the final heat damage. About 90% of both GAP and LCT contents was due to the ultrahigh-temperature sterilization process itself. This effect was more than halved when the pH of the ingredient mixture was adjusted from 7.2 to 6.9 before sterilization or when the product recirculated in the plant was discarded. Up to 60 and 20%, respectively, of the FUR and LAL levels in the finished product were already present in protein ingredients (whey powder, whey protein concentrate). Accurate optimization of processing conditions and scrupulous selection of raw materials proved to be effective means to minimize heat damage in such special food products.

-The sensorial and physico-chemical characteristics described in the product specification for most PDO cheeses are inadequate to verify the compliance of cheeses on the market with the registered designation, particularly for grated products. During the past few years, much research has indicated the analytical parameters suitable for distinguishing Grana Padano (GP) from other similar hard cheeses. The characterization of grated GP is currently based on 3 analytical parameters, related to different aspects of cheese processing, which are: (i) the measurement of alkaline phosphatase (ALP) activity, a marker for possible heat treatment applied to milk, in the outermost layer of the cheese, just below the rind; (ii) the identification of specific peptides, that are identified only in the rind, due to the very slow progress of proteolysis in the rind during GP cheese ripening; and (iii) the free amino acid (FAA) composition. In the present study, we developed an extraction method, based on density gradient centrifugation of solubilized cheese, to separate the outermost layer of the cheeses from the rest in grated cheese, and we proposed a simplified criterion to evaluate the "typicalness" of the FAA pattern. The quality control scheme based on ALP activity, detection of specific peptides and FAA pattern was applied to more than 300 samples of marketed grated GP collected over three years, 10% of which were collected outside Italy, and ∼ 100 samples of grated generic ("Grana-type") hard cheeses. The results demonstrate that the simultaneous application of the three parameters allows one to distinguish grated GP from similar, non-PDO grated hard cheeses, and to recognize irregular GP cheeses.Grana Padano cheese / quality control / alkaline phosphatase / cheese peptides / free amino acidsArticle published by EDP Sciences 596 S. Cattaneo et al. Résumé -Fromage Grana Padano râpé : nouvelles indications pour le contrôle de qualité et pour reconnaître les imitations.Les caractéristiques sensorielles et physico-chimiques indiquées dans le cahier des charges de la plupart des fromages AOP sont peu utiles pour vérifier la conformité des produits mis sur le marché avec l'appellation, surtout pour les fromages râpés. Au cours des dernières années, plusieurs recherches ont mis en évidence les paramètres analytiques capables de distinguer le fromage Grana Padano (GP) d'autres fromages à pâte dure similaires. Actuellement, la caractérisation du GP râpé se base sur trois paramètres analytiques, liés à différents aspects de la production : (i) l'activité de la phosphatase alcaline (ALP), indicateur d'un possible traitement thermique du lait, mesurée dans la pâte du fromage, juste en-dessous de la croûte ; (ii) l'identification de peptides spécifiques de la croûte, du fait de la protéolyse très réduite dans cette partie durant l'affinage ; et (iii) la composition en acides aminés libres (AAL). Dans la présente étude, nous avons développé une méthode d'extraction basée sur la centrifugation en gradient de densité du fromage...