Interactions holding protein structure in cheese has been a subject of considerable investigation, with conclusions varying among studies. We present a review on this topic, covering fresh curds, ripened cheeses, and processed cheeses. We discuss the usual chemicals and conditions used to probe different types of interactions. Furthermore, we did our own study with solutions of urea, SDS, EDTA, NaCl, and NaOH, at different concentrations and combinations, for Emmental cheese. To quantify solubilized protein, we developed a modification of a spectrometric-based method that can be conveniently employed to quantify total protein in cheese, with statistically similar results to those obtained by the Kjeldahl method. Our results point out that caseins in the Emmental cheese are held together by a set of hydrophobic interactions, hydrogen bonds, and other electrostatic ones, including ionic bonds. Hydrogen bonds seem to have an important role, comparable to hydrophobic interactions, a conclusion not commonly reported for cheese structures.

Research background: Fresh cheese varieties represent an important share of the whole cheese market. Although with great variability in terms of composition and method of preparation, fresh cheese varieties are bland in flavor and their production originates whey drainage. On the other hand, the cheese market is also responsible for a significant amount of food waste. These motivated the development of a novel fresh cheese incorporating ripened cheese, which can then represent a valorization of ripened cheese surpluses. Experimental approach. A variable amount of ripened cheese was dispersed in a paste of gelatinized starch (normal corn or waxy rice) in milk, producing melted cheese bases. These cheese bases were diluted with milk, sometimes enriched with skim milk powder, and then renneted. The resultant fresh cheese was characterized for macronutrients content, and physical properties. Sensory analyses of samples incorporating mature Cheddar, goats’, or ewes’ cheese were carried out. Results and conclusions. Gel formation of the initial mixture was hindered above 8 % (m/m) incorporation of ripened cheese, which could be overcome by the addition of skim milk powder. These observations are corroborated by the hardness values from texture analysis tests. Evaluation of syneresis of different samples enabled to conclude that addition of 2 % (m/m) starch and of 2.8 % (m/m) skim milk powder contribute to reduce its magnitude by half. Sensory analysis with a consumer panel indicated a preference for a more consistent texture of the fresh cheese, and for the Cheddar flavor. Novelty and scientific contribution. A novel fresh cheese variety incorporating dispersed ripened cheese was prepared. The proposed method is versatile and quite straightforward and does not use polyphosphate salts or originate whey wastage. The fresh cheese physical and sensorial properties can be manipulated by the amounts and types of starch, ripened cheese, and skim milk powder added; such tailoring of fresh cheese properties widens product portfolio capacity for a larger number of consumer groups. The ripened cheese added can come from non-sellable pieces and unsold stocks from the retail sector, contributing to a reduction of food waste.

22 Yogurts are generally enriched with dairy proteins powders. This research developed a 23 cheese-fortified yogurt -yogucheese. First, Emmental cheese was dispersed into sub-24 millimeter particles by melting it in a hot paste of gelatinized corn starch (CS), or waxy rice 25 starch (WRS) in milk, forming a melted cheese base (MCB). This MCB was mixed with 26 further milk in different proportions, before addition of starter culture and fermentation.27 The products were then characterized in terms of macronutrient composition and physical 28 properties. The new yogurts had a firmer gel structure, lower syneresis, and higher viscosity 29 than controls, and were stable for 14 days.