Effect of milk protein standardization, by ultrafiltration, on the manufacture, composition and maturation of Cheddar cheese

Abstract

SummarySkim milks were pre-acidified to pH 6·4 and concentrated by ultra-filtration to give retentates with protein levels of 210 g/1. Retentates were blended with skim milk and cream to give standardized milks with protein levels ranging from 30 to 82 g/1. These were used for the manufacture of Cheddar cheese in conventional equipment. Increasing milk protein level resulted in reduced gelation times, increased curd firming rates and a decrease in the set-to-cut time when cutting at equal firmness values (i.e. elastic modulus, G′, ∼ 16 Pa). As the curd firming rates increased with milk protein level, it became increasingly difficult to cut the curd cleanly, without tearing, before the end of the cutting cycle. Reflecting the tearing of curd, and consequent curd particle shattering, fat losses in the running wheys were greater than those predicted on the basis of volume reduction (due to ultrafiltration) for milks with protein levels > 50 g/1. Reduction of setting temperatures, in the range 31–27 °C, and the level of added rennet brought the set-to-cut times and curd firming rates of concentrated milks closer to those of the control milk. While increasing milk protein level in the range 30–70 g/1 had little effect on cheese composition, it resulted in slower proteolysis and maturation.

Pre-treatment of cheese milk: principles and developments

“…When cheese-milk was partially supplemented with UF retentate, RCT decreased [113] and increasing protein level resulted in reduced gelation time and increased firming rates [53].…”

“…Essentially, UF enables concentration of casein content and recovery of whey proteins for cheese manufacture [51,53]. UF of milk at pH 6.6-6.8 concentrates mineral salts bound to casein micelles in the same proportion as proteins and increases buffering capacity, which affects acidification, pH, rennet coagulation and rheological characteristics of curd [98].…”

“…UF of milk at pH 6.6-6.8 concentrates mineral salts bound to casein micelles in the same proportion as proteins and increases buffering capacity, which affects acidification, pH, rennet coagulation and rheological characteristics of curd [98]. Acidification before or during UF [53] and/or salt addition to retentate leads to solubilisation of colloidal calcium in the permeate.…”

Avaliação do rendimento do queijo tipo prato obtido por modificações no processo tradicional de fabricação

“…Assim, em queijos elaborados a partir de LCUF, em que se faz uso da tecnologia tradicional de fabricação na qual a massa do queijo é cortada e trabalhada, a redução do volume de soro perdido por sinérese [18] associada a um coágulo mais firme [17,35,36] acaba provocando lesões nessa massa, com perda de fragmentos que diminuem a recuperação de componentes do leite no queijo e conseqüentemente prejudicam o seu rendimento [3,36].…”

“…GUINEE et al [17] e RENNER EL-SALAM [35] também observaram que quanto maior o FCV do concentrado, mais firme e mais difícil de cortar se torna o coágulo. Assim, muitas vezes, ao cortá-lo ele se arrebenta, causando perdas de partículas e de gordura no soro, em quantidades maiores do que as previstas com base na redução que se tem no volume de soro liberado devido a ultrafiltração.…”