H pressure processing
- 2. Pascalization or bridgmanization Anwar Hussain For Class BS-IV Institute of Microbiology Faculty of Natural Science Shah Abdul Latif University, Khairpur
- 3. HISTORY • High hydrostatic pressure (HHP), or ultra high pressure (UHP ) • First research in 1890s-milk pathogens • Non-thermal processing technology (combination with heat possible) • First commercialised in Japan in the early 1990s for pasteurisation of acid foods for chilled storage • High pressure treated foodstuffs have been marketed in Japan since 1990, in Europe and the United States since 1996 & Australia since 2001 • Rapid commercialisation since 2000 History
- 4. INTRODUCTION • High pressure processing is a promising “ non-thermal” technique for food preservation. • Consumers demand for high quality, natural and fresh tasting food, free from preservatives with a clean label and an extended shelf life has increased. • High pressure processing inactivates microorganisms, denatures proteins and extends the shelf life of food products. • It is an opportunity to preserve food, by applying intensive pressure, without adversely affecting organoleptic, textural and nutritional qualities as thermal processing like pasteurization and sterilization may do. Introduction
- 5. INTRODUCTION • In HPP, the product is packaged in a flexible container (usually a pouch or plastic bottle), the food product to be treated is placed in a pressure vessel capable of sustaining the required pressure, the product is submerged in a liquid which acts as the pressure-transmitting medium. • High pressure processing is carried out with intense pressure in the range of 100 – 1000 Mpa with or without heat, allowing most foods to be preserved with minimal effect on taste, texture & nutritional characteristics. Introduction
- 6. WHY HPP? 1. Application of high pressure can cause : • Inactivation of parasites, plant cells and Vegetative micro-organisms, Some fungal spores, Many food borne viruses • Enzymes are selectively inactivated • Macromolecules can change Conformation • Small molecules are generally unaffected 2. High pressure is instantaneously and uniformly applied to the sample 3. Compression is fully reversible STATIC HIGH PRESSURE Why HPP
- 7. Structural and functional changes in microorganisms at different pressures Change in Microbes at Pressure
- 8. ADVANTAGES OF HPP • High pressure is not dependent of size and shape of the food. • It does not break covalent bonds, maintaining thus natural flavor of the products. • It can be applied at room temperature thus reducing the amount of thermal energy needed during conventional processing. • Since HPP is isostatic, the food is preserved evenly throughout without any particles escaping the treatment. • The process is environment friendly since it requires only electric energy and there are no waste products. Advantages of HPP
- 10. PRINCIPLES OF HPP There are two general scientific principles to the use of high pressure in food processing:- 1. Le- chatelier’s principle 2. Iso-static principle Principle of HPP
- 11. Le Chatelier’s Principle • Any phenomenon (phase transition, change in molecular Configuration, chemical reaction) accompanied by a decrease in volume is enhanced by pressure. Accordingly, pressure shifts the system to that of lowest volume. Le- chatelier’s Principle
- 12. • The food products are compressed by uniform pressure from every direction and then returned to their original shape when the pressure is released. • The products are compressed independently of the product size and geometry because transmission of pressure to the core is not mass/time dependant thus the process is minimized • If a food product contains sufficient moisture, pressure will not damage the product at the macroscopic levels as long as the pressure is applied uniformly in all directions Iso-static Principle
- 13. PACKAGING REQUIREMENTS FOR HPP • HPP requires airtight packages that can withstand a change in vol. corresponding to the compressibility of the product • The packaging used for high pressure treated foods must be able to accommodate 15% reduction in vol. and return to its original vol. • Plastic films are accepted for high pressure processing • Vacuum packed product are ideally suited for high pressure. Packaging Requirements
- 14. Table-1.Pressure required to achieve a 5-log cycle inactivation ratio for microorganisms for a 15 minute treatment: • Microorganism Pressure (Mpa) • Yersinia enterocolitica 275 • salmonella typhimurium 350 • Listeria monocytogens 375 • Salmonella enteritidis 450 • E. Coli O157:H7 680 • Staphylococcus aureus 700 Pressure to inactivate microbes for 15 minutes treatment
- 16. CONCLUSION • High pressure technology proposes a great potential to develop new “minimally” treated foods with high nutritional and sensory quality novel texture and with an increased shelf life. • The novelty of HPP technology and high equipment cost are barriers to its commercialization but increased consumer’s demand for fresher-tasting foods containing fewer preservatives drives an increase in this segment. • HPP can preserve food products without heat treatment or chemical preservatives, and its ability to ensure safety and significantly extended refrigerated shelf life has opened new market opportunities particularly in the area of • “natural”, preservative free food products. Conclussion
- 17. Limitations 1. Food enzymes and bacterial spores are very resistant to pressure and require very high pressure for their inactivation. 2. The residual enzyme activity and dissolved oxygen results in enzymatic and oxidative degradation of certain food components. 3. Most of the pressure-processed foods need low temperature storage and distribution to retain their sensory and nutritional qualities. Limitations