Draining and salting as responsible key steps in the generation of the acid-forming potential of cheese: Application to a soft blue-veined cheese

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Inglés. A disregarded nutritional feature of cheeses is their high acid-forming potential when ingested, associated with deleterious effects for consumers' health. This work aimed to characterize the generation of the acid-forming potential of a blue-veined cheese during manufacturing to identify the main key steps of the process involved in this phenomenon. Sampling was performed on 3 batches at 10 steps of the cheese-making process: reception of raw milk, pasteurization, maturation of milk, coagulation, stirring, draining of the curds and at 4 ripening stages: 21, 28, 42, and 56 d. Acid-forming potential of each sample was evaluated through (1) the calculation of the potential renal acid load (PRAL) index (considering protein, Cl, P, Na, K, Mg, and Ca contents) and (2) its organic anion content (lactate and citrate), considered as alkalinizing elements. Draining and salting were identified as the main key steps responsible for the generation of the acid-forming potential of cheese. The draining process induced an increase in the PRAL index from 1.2 mEq/100 g in milk to 10.4 mEq/100 g in drained curds due to the increase of the dry matter and the loss of alkaline minerals into the whey. The raise of PRAL value (20.3 mEq/100 g at d 56) following salting resulted from an imbalance between the strong acidogenic elements (Cl, P, and proteins) and the main alkalinizing ones (Na and Ca). Particularly, the Cl element had a major effect on the PRAL value. Regarding organic anions, draining induced a loss of 93% of the citrate content in initial milk. The lactate content increased as fermentation occurred (1,297.9 mg/100 g in drained curds), then decreased during ripening (519.3 mg/100 g at d 56). This lactate level probably contributes to moderate the acidifying potential of end products. Technological strategies aiming to limit the acid-forming potential of cheeses are proposed and would deserve further research to evaluate their nutritional relevance.