Applications of high pressure technology for milk processing

Abstract

: Consumers growing preference for convenient, fresh-like, healthy, palatable, additive-free, high quality and micro-biologically safe food products creates the need to explore beyond the conventional thermal processing techniques. Consequently, a number of non-thermal approaches to food processing have evolved, of which High Pressure Processing (HPP) technology has proven to be very valuable. Attention in HPP applications on milk and dairy products has recently increased. Studies in this arena have shown that pressures between 300 and 600 MPa are effective to inactivate milk -borne pathogens. In addition to microbial destruction in milk, it has been reported that HPP improves rennet or acid coagulation of milk, ripening of cheese, syneresis and firmness in fermented milk product, ageing of ice cream mix, ripening and fat crystallization of dairy cream, without damaging important natural quality characteristics, such as taste, flavour, vitamins, and nutrients. Present paper highlights the research findings and effects of HPP technology in milk processing.

Sensory properties of high-pressure-treated milk

“…A moderately intense heat treatment causes colour changes, presumably due to serum protein denaturation and aggregation. As a result pasteurized milk become a whiter (Walstra et al, 2006;Chopde et al 2014). Also in the present study, pasteurized milk was whiter comparing with sample HPM resulting in higher L* values.…”

“…have been explored to meet new demands of consumers for fresh products without food additives. Among these technologies, high-pressure processing (HPP) seems to be promising one for food applications (Chopde et al, 2014) and at this moment is the most commercially developed non-thermal technology, with very good acceptance by consumers (Bello et al, 2014). One of the important goals of milk preservation methods by its high-pressure treatment is to reduce microbial loads and inactivate enzymes.…”

Effects of High-Pressure Technology on the Functional Properties of Milk and Fermented Milk Products

“…With the application of HHP the size and number of casein micelles increases (as casein micelle dissociates into sub-micelles due to weakening of hydrophobic and electrostatic interactions between sub-micelle and further aggregation of sub-micelle to big cluster) as spherical particles change to form chains or clusters of sub-micelles. Size distribution of spherical casein micelles decreases from 200 to 120 nm; maximum changes have been reported to occur between 150-400 MPa at 20 °C [1,22,[27][28][29].…”

“…Acidification of yoghurt milk with GDL (glucono-δ-lactone) at 200 MPa for 20 min resulted in fine coagulum, homogeneous gel than that of heat treated milk [19,22,36].…”

“…In dairy food processing HHP is used for milk stabilization and to define the pressure-induced structural modifications of the main milk constituents (caseins, whey proteins, fat globules, enzymes), inactivation of microorganisms, depression of freezing point of water, and recovery of lactose and proteins from dairy waste water (nutraceuticals, drugs, food additives [1,7,11,[19][20][21][22].…”