Pressure fryers

Deep-fat fryers may also operate at a higher pressure (9—32 psi). These devices have been developed to meet particular needs primarily in certain catering outlets, especially those devoted to chicken frying because of the uniform color and improved texture (higher moisture content) conferred to products. Pressure fryers may reduce the frying time considerably, but they can also increase frying oil deterioration rate since steam retention within the fryer increases free fatty acids content (Moreira et ah, 1999). 

The principal categories of restaurant fryers are (1) countertop fryers, (2) floor-type fryers, (3) pressure fryers, and (4) turkey fryers. 

Countertop pressure fryers (see Figure 2) are especially suitable for frying batter-coated fish or shrimp in small restaurants and as experimental fryers for research work. These fryers have a single pressure setting and an automatic shutoff device. 

Pressure fryers are used for frying chicken, meat products, and breaded shrimp. These fryers are equipped with lids that are tightly held to maintain pressure... 

The oil does not deteriorate in a pressure fryer as rapidly in a conventional fryer. This is because the oil is not in contact with air during frying. 

Figure 5. Pressure fryer (floor model). (This figure is available in full color at http // www.mrw.interscience.wiiey.com/biofp.)...

Consumers try to use a pressure cooker as a pressure fryer. This practice should be avoided because of the following reasons ... 

It is important to note that pressure cookers are designed to cook foods under pressure, and they are safe when they are used for cooking products. However, when they are used as pressure-fryers, small amounts of oil come in contact with the gasket and damage it. It evenmally can melt the gasket, causing a burst of hot oU out of the pan. This can injure people or can even cause a fire. Therefore, pressure cookers are not recommended for pressure frying. 

Fryer, P.J. 210,229 Fuller, E. N. 584,655 Fully developed flow 61.681 Fundamental units, choice of 12 Further reading, flow and pressure measurement (Chapter 6) 272... 

Fryer, D. M. and Harvey, J. F. (1997) High Pressure Vessels (Kluwer). 

Fryer DM., Harvey J.F., 1998. High pressure Vessels, Chapman Hall, London. 

FIGURE 4.20 Variation in laminar flame speeds with pressure for some stoichiometric fuel-air mixtures (after Westbrook and I fryer [2]). 

Fryer, D. M., "High Pressure Safety System Analysis- A Proposed Method", Design, Inspection, and Operation of High Pressure Vessels and Piping Systems, PVP, Vol. 48. 

D.M. Fryer, J.F. Harvey High Pressure Vessels, Chapman Hall, Int. Thomson Publishing, New York 1998... 

Whitnah, C.H., Rutz, W.D., Fryer, H.C. 1956. Some physicochemical properties of milk. III. Effects of homogenisation pressures on the viscosity of whole milk. J. Dairy Sci. 39, 1500-1505. 

Campbell, G.M., Rielly, C.D. Fryer, P.J., Sadd, P.A (1998). Aeration of bread dough during mixing Effect of mixing dough at reduced pressure. Cereal Food World43, 163-167. 

Jenner G. A., Foley S. F., Jackson S. E., Green T. H., Fryer B. J., and Longerich H. P. (1994) Determination of partition coefficients for trace elements in high pressure-temperature experimental run products by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS). Geochim. Cosmochim. Acta 58, 5099-5103. 

Par-fried foods as well as other products require different pressure settings. Manufacturers of these fryers indicate the recommended pressure settings for the various types of products to be cooked in their fryers. 

The fryer is operated under vacuum. Typical operating pressure is <100 mm of mercury. 

Fryer DM, Harvey JF. High Pressure Vessels. Chapman and Hall 1998. 

Nodop Mazuiek SG, Li J, Nabozny GH, Reinhart GA, Muthukumarana AC, Harrison PC, Fryer RM (2011) Functional biomarkers of musculoskeletal syndrome (MSS) for early in vivo screening of selective MMP-13 inhibitors. J Pharmacol Toxicol Methods 64 89-96 Norton K, lacono G, Vezina M (2009) Assessment of the pharmacological effects of inotropic drugs on left ventricular pressure and contractility an evaluation of the QA interval as an indirect indicator of cardiac inotropism. J Pharmacol Toxicol Methods 60 193-197 Onishchenko N, Fischer C, Wan Ibrahim WN, Negri S, Spulber S, Cottica D, Ceccatelli S (2011) Prenatal exposure to PFOS or PFOA alters motor function in mice in a sex-related manner. Neurotox Res 19 452-461... 

Knoerzer, K., )uliano, P., Gladman, S., Versteeg, C., and Fryer, P.J. (2007) A computational model or temperature and sterility distribuhoiis on a pilot-scale high-pressure high-temperature process. AIChE Journal,... 

Most commercial fryers are continuous types with direct or indirect heating elements, gas-fired tubes, or high-pressure steam tubular heaters. The most adequate fryers have continuous oil circulation between the fryer tank and the heat exchanger for precise control and distribution of the temperature, as well as metering paddles and a submerger for the control of the residence time. In addition, they are designed to continuously filter out fines and facilitate cleaning. 

---