1. High Pressure Processing
1.1 Introduction
The use of high hydrostatic pressure to preserve foods is the first truly new method of preserving foods since Nicolas Appert developed the use of heat to preserve foods in sealed glass bottles over 200 years ago. High pressure does not depend on heat, chemicals, reduced water activity, or reduced temperatures to control pathogens or spoilage microorganisms. Pressures in the range of 200-600 MPa have been found to unfold proteins so that they lose their biological functions as cell wall membranes and enzymes (Farkas, 2016). In contrast to heat, high pressure does not break covalent bonds. High pressure is transferred instantly throughout a package of food independently of size, shape or composition. …show more content…
sugars, preservatives;
- potential for new food product designs due to the creation of new textures, tastes and functional properties;
- improved emulsifying capacity, water-binding capacity, stability, gelling and foaming of proteins through unfolding of their tertiary and quaternary structures;
- ability to process in semi-continuous and continuous (liquid foods) modes; (Eley, 1992; Ogawa et al., 1992; Zimmerman and Bergman, 1993).
- The process is environmentally friendly since it requires only electric energy and there are no waste products (Yaldagard et. al, 2008).
Some limitations of high pressure processing:
- Food enzymes and bacterial spores are very resistant to pressure and require very high pressure for their inactivation.
- The residual enzyme activity and dissolved oxygen can result in enzymatic and oxidative deterioration of certain food products.
- Most pressure processed foods need low temperature storage and distribution to retain their sensory and nutritional attributes (Yaldagard et. al, …show more content…
Work showed that there would be very little deterioration in the ‘fresh’ flavour of the product during room temperature storage compared to the product being heat treated (Farkas, 2016). This worked remained largely ignored by food processors even when his 1914 paper was cited in West Virginia Creuss’ Commercial Fruit and Vegetable Products which was first published in 1924. In the following years, a considerable amount of research was undertaken, with a number of papers being published which detailed the effects of high pressure on microbes, starches and various proteins including enzymes and enzyme activity (Johnson et al., 1954). Despite this, food manufacturers decided that the application of high pressure treatment for commercial food manufacture would not be practical or economical. Pressure vessels, pumps and instrumentation needed significant improvements and research. Equipment capable of these pressures was rare and would not be readily accessible to food manufacturers. Another problem with the development of this process in food manufacturing was the unavailability of low gas transmission, food grade, flexible, tough
1.1 Introduction
The use of high hydrostatic pressure to preserve foods is the first truly new method of preserving foods since Nicolas Appert developed the use of heat to preserve foods in sealed glass bottles over 200 years ago. High pressure does not depend on heat, chemicals, reduced water activity, or reduced temperatures to control pathogens or spoilage microorganisms. Pressures in the range of 200-600 MPa have been found to unfold proteins so that they lose their biological functions as cell wall membranes and enzymes (Farkas, 2016). In contrast to heat, high pressure does not break covalent bonds. High pressure is transferred instantly throughout a package of food independently of size, shape or composition. …show more content…
sugars, preservatives;
- potential for new food product designs due to the creation of new textures, tastes and functional properties;
- improved emulsifying capacity, water-binding capacity, stability, gelling and foaming of proteins through unfolding of their tertiary and quaternary structures;
- ability to process in semi-continuous and continuous (liquid foods) modes; (Eley, 1992; Ogawa et al., 1992; Zimmerman and Bergman, 1993).
- The process is environmentally friendly since it requires only electric energy and there are no waste products (Yaldagard et. al, 2008).
Some limitations of high pressure processing:
- Food enzymes and bacterial spores are very resistant to pressure and require very high pressure for their inactivation.
- The residual enzyme activity and dissolved oxygen can result in enzymatic and oxidative deterioration of certain food products.
- Most pressure processed foods need low temperature storage and distribution to retain their sensory and nutritional attributes (Yaldagard et. al, …show more content…
Work showed that there would be very little deterioration in the ‘fresh’ flavour of the product during room temperature storage compared to the product being heat treated (Farkas, 2016). This worked remained largely ignored by food processors even when his 1914 paper was cited in West Virginia Creuss’ Commercial Fruit and Vegetable Products which was first published in 1924. In the following years, a considerable amount of research was undertaken, with a number of papers being published which detailed the effects of high pressure on microbes, starches and various proteins including enzymes and enzyme activity (Johnson et al., 1954). Despite this, food manufacturers decided that the application of high pressure treatment for commercial food manufacture would not be practical or economical. Pressure vessels, pumps and instrumentation needed significant improvements and research. Equipment capable of these pressures was rare and would not be readily accessible to food manufacturers. Another problem with the development of this process in food manufacturing was the unavailability of low gas transmission, food grade, flexible, tough