Use of high hydrostatic pressure on yogurt manufacture and casein micelle disruption.

摘要

High hydrostatic pressure is a nonthermal technology industrially applied for the shelf life extension of foods through microbial and enzyme inactivation. The potential use of this technology exists in the dairy industry not only from the microbial and enzyme inactivation stand point but also for improving quality and yield of dairy products such as yogurt and to exploring new functional properties of traditional dairy ingredients such as casein proteins.; Yogurts manufactured from full fat milk subjected to high hydrostatic pressure (676 MPa) for 30 min exhibited similar yield stress and water holding capacity characteristics to yogurts made from thermally treated milk. The combined action of high hydrostatic pressure (400–500 MPa) for micelle disruption and thermal treatment for whey protein denaturation resulted in yogurts having less syneresis and larger yield stress and elastic modulus than yogurts manufactured from milk receiving only a thermal treatment.; The determination of yield stress in yogurts using the vane geometry was well correlated (r > 0.97) with the sensory firmness evaluated by trained panelists for experimental yogurts containing selected concentrations of gums as well as commercial yogurts. Additionally, the empirical residual stress exhibited significant correlation (r > 0.90) with the sensory viscosity in commercial yogurts. High hydrostatic pressure in the 250 to 300 MPa range promoted extensive disruption of casein micelles into sub-micelles. The addition of whey proteins into the casein micelle isolate protected the micelles from disruption only when the blend was thermally treated before high pressure. Based on the above-mentioned results, it is clear that high hydrostatic pressure has an important potential for the improvement of functional properties of yogurt and other protein based dairy products.