Hurdle technology ppt
- 1. Hurdle Technology Prepared by P. Shylaja 1008-15-824-010 Food technology deportment Osmania university
- 2. Introduction A combination of food preservation technique is called hurdle technology Factors used for food preservation are called ‘hurdles’ The concept of combining several factors has been developed by Leistner(1995)
- 3. Raising factors for hurdle technology Consumer demands for healthier foods Shift to ready-to-eat and convenience foods Consumer preference for more natural food
- 6. Basic aspects Food preservation implies putting microorganisms in a hostile environment, in order to inhibit their growth or shorten their survival or cause their death. The feasible responses of microorganism to this hostile environment determine whether they may grow or die.
- 8. Homeostasis Microorganisms react homeostatically to stress factors. Microorganisms undergo many important homeostatic reactions. Preservative factors functioning as hurdles can disturb one or more of the homeostasis mechanisms, thereby preventing microorganisms from multiplying and causing them to remain inactive or even die. Food preservation is achieved by disturbing the homeostasis of microorganisms.
- 9. Metabolic exhaustion Metabolic exhaustion of microorganisms cause autosterilization of a food. This was first observed by Leistner and Karan- Djurdjic, 1970 in experiments with mildly heated liver sausage adjusted to different water activities by the addition of salt and fat, and the product was inoculated with Clostridium sporogenes and stored at 37*C. Clostridial spores surviving the heat treatment vanished in the product during storage.
- 10. Stress reactions synthesis of protective stress shock proteins is induced by several stresses including heat, pH, aw, ethanol, oxidative compounds,. stress responses of microorganisms might hamper food preservation and become problematic for the application of hurdle technology. The use different stresses at the same time prevent the synthesis of those protective proteins may cause the microorganisms to become metabolically exhausted. This antimicrobial action of combining hurdles is known as multitarget preservation.
- 11. Multitarget preservation food An important aspect for efficient and effective preservation of targeted food material. Hurdles applied in the targeted food material might not just have effects on microbial stability but they could act synergistically. Synergistic effect could be achieved in the targeted food, if the hurdles affects different targets such as pH, aw, Eh, enzyme systems simultaneously within the microbial cell and thus disturb the homeostasis of the microbes rendering it difficult for the microbes to synthesize different stress shock proteins and to maintain their homeostasis. Application of several hurdles simultaneously would lead to an optimal microbial stability and effective food preservation.
- 12. Hurdle effect
- 13. Example 1 represents a food containing six hurdles: high temperature during processing (F value), low temperature during stor age (t value), water activity (aw), acidity (pH), redox potential (Eh), and preservativ es (pressure). The microorganisms present cannot overcome these hurdles, and thus the food is micr obiologically stable and safe.
- 15. Examples
- 17. Case study -1 Low cost preservation of cauliflower for 180 days through hurdle technology Research objectives 1.To develop a suitable hurdle technology (appropriate concentration & combinations of preservatives, storage temperatures & storage periods) for preservation of cauliflower for 180 days. 2.To study the effect of hurdle technology (different concentration & combinations of preservatives, storage temperatures & storage periods) on the microbial content of preserved cauliflower. 3.To study the effect of hurdle technology (different concentration & combinations of preservatives, storage temperatures & storage periods) on the physical & sensory properties of preserved cauliflower. 4.To estimate the cost of preservation of cauliflower for 180 days by hurdle technology
- 18. Method of preservation First cauliflower head were cut into 5×3×3 cm. then thoroughly washed in tap water and distilled water. After washing blanched at 100°C for 60sec. then steeped into different concentrations & combinations of preservatives.
- 19. P0 -Control sample- fresh without treatment P1- 8% Salt + 500 ppm Potassium metabisulphite + 100 ppm Sodium benzoate P2 -10% Salt + 400 ppm Potassium metabisulphite + 200 ppm Sodium benzoate P3- 12% Salt + 300 ppm Potassium metabisulphite + 300 ppm Sodium benzoate P4 - 8% Salt + 0.3% Citric acid + 300 ppm Potassium metabisulphite + 300 ppm Sodium benzoate P5 - 10% Salt + 0.2% Citric acid + 400 ppm Potassium metabisulphite + 200 ppm Sodium benzoate P6 -12% Salt + 0.1% Citric acid + 500 ppm Potassium metabisulphite + 100 ppm Sodium benzoate
- 20. Then aseptically packed into food grade polyethylene pouches and stored at two different level of temperatures. T1 ambient temperature – 30 to 37 °C T2 refrigeration temperatures – 5 to 7 °C for different time intervals i.e. 0, 30, 60, 90, 120, 150 & 180 days respectively. These preserved cauliflowers were studied for their microbial, physical, sensory, & total cost of preservation.
- 21. Results Treatments in which mean of yeast & mold count were found lowest with a storage period of 180 days are P4/T1, P4/T2 & P5/T2. Lowest water activity & lowest pH were found in P4/T2 in a storage period of 180 days.
- 22. Conclusion of research All the treatments combination was not effective for preservation of cauliflower till 180 days of storage period. Only 3 treatments - P4/T1, P4/T2 & P5/T2 were microbial safe till 180 days. Treatment P4/T2 was found best in physical & sensory but cost of preservation through treatment P4/T1 for 180 days of storage period was found cheapest. Best hurdle treatment for low cost preservation of cauliflower for 180 days was P4/T1 combination.
- 23. Conclusion The physiological responses of microorganisms during food preservation (i.e., their homeostasis, metabolic exhaustion, and stress reactions) are the basis for the application of advanced hurdle technology. The disturbance of the homeostasis of microorganisms is the key phenomenon of food preservation. Microbial stress reactions may complicate food preservation, whereas the metabolic exhaustion of microorganisms present in stable hurdle-technology foods could foster food preservation.
- 24. The novel and ambitious goal for an optimal food preservation is the multitarget preservation of foods, in which intelligently applied gentle hurdles will have a synergistic effect. After the targets of different preservative factors within the microbial cells have been elucidated, and this should become definitely a major research topic in the future, preservation of foods could progress far beyond the state-of-the-art of the hurdle technology approach as we know it today.
- 25. References Basic aspects of food preservation by hurdle technology by Lothar Leistner. (International Journal of Food Microbiology). LOW COST PRESERVATION OF CAULIFLOWER FOR 180 DAYS THROUGH HURDLE TECHNOLOGY Jyoti Sinha, Ena Gupta and Ramesh Chandra (INTERNATIONAL JOURNAL OF FOOD AND NUTRITIONAL SCIENCES ). Hurdle Technology in Food Preservation by Mohammad Shafiur Rahman.