The Effect of Liposome-Encapsulated Bacillus subtilis Neutral Proteinase on Manchego Cheese Ripening

Abstract

Neutral proteinase from Bacillus subtilis was entrapped in dehydration rehydration liposomes, which were added to pasteurized ewe milk to accelerate Manchego cheese ripening; proteinase level was, 040 Anson units/kg in fresh curd. Encapsulated proteinase had no apparent effect on whey composition or on dry cheese yield, but experimental cheese showed a higher DM from d 15 and a higher protein content from d 30. Proteolysis was enhanced by encapsulated proteinase by 24h after manufacture; 26.5% of αs1-casein and 53.4% of β-casein that was initially present in milk had been degraded in 1-d-old control cheese and 51.3 and 83.5%, respectively, in experimental cheese. After 90 d of ripening, amounts of N that were soluble at pH 4.6, in TCA, and in phosphotungstic acid were 34.09, 17.50, and 11.88% in experimental cheese and 20.09, 13.67, and 8.58% in control cheese, respectively. Hydrophobic and hydrophilic peptides measured at 214 and 280nm were higher in experimental cheese than in control cheese from d 15. Higher fracturability, elasticity, and hardness values were recorded for experimental cheese despite its more extensive proteolysis; the firmer texture was ascribed to its higher DM content. No bitter flavor defect was detected in experimental cheese, although development of flavor intensity was accelerated by encapsulated proteinase.