Quality of frying oil

Most countries in Europe and Chile have adopted some form of regulations to control the quality of frying oil at the restaurants. Most of these countries have decided that the oil reaches the end point when the polar material in the oil exceeds a certain level. This level is somewhat different for different countries. This regulation compels the restaurant personnel to learn the techniques of testing fryer oil for quality and to determine when to discard it. Table 4 lists the regulatory limits on the restaurant oil quality (3). 

The volatiles in the frying oil increase in the beginning, but then decrease as frying continues. The most important volatiles for the quality of frying oil are saturated aldehydes Cg-Cg, enals (e.g., 2-decenal), dienals (e.g., 2,4-heptadienal), and hydrocarbons (hexene, hexane, heptane, octane, nonane, and decane). The presence of volatile oxidation products formed during the frying process was discussed by Perkins (1996) and Nawar (1998). 

Orthoefer, F.T. and Cooper, D.S. 1996. Initial quality of frying oil. In Perkins, E.G. and Erickson, M.D. (Eds.), Deep Frying Chemistry, Nutrition and Practical Applications, AOCS Press, Champaign, IL, pp. 29-42. 

T Asap, MA Augustin. Effect of frying oil quality and TBHQ on the shelf-life of potato crisps. J Sci Food Agric 37 1045-151, 1986. 

Figure 3 indicates that there are several reactions that take place simultaneously in the fryer. Also, the degradation of product flavor is associated with oxidation and other reactions in the oil. Therefore, it is important to note that measurement of free fatty acid in the fryer oil does not necessarily represent the absolute quality of the oil. This is because the free fatty acid content in the fryer oil ranges from 0.25% to 0.40% for most snack food products. In many frying operations, a portion of the fryer oil is replaced by fresh oil when the free fatty acid level exceeds 0.35%. At this low level of free fatty acid, there is little correlation between the free fatty acid... 

Efforts have been made to reduce the volume of oil in the frying system in order to reduce the oil turnover time to preserve the quality of the oil. 

Teah, Y.K. (1988) Improvements in the frying quality of vegetable oils by blending with palm olein, in Palm Oil Developments, Malaysian Palm Oil Board, Malaysia, pp. 1 1. 

Warner, K. M. Gupta. Potato chip quality and frying oil stability of high oleic acid soybean oil./. FoodSci. 2005, 70, S395-S400. 

The intrinsic qualities of coconut oil make it very suitable for household culinary preparations, as frying oil, in non-dairy products, coffee whiteners and... 

B. Innawong, P. MaUikaijunan, J.E. Marcy, The determination of frying oil quality using a chemosensory system. LWT Food Sci. Technol. 37, 35-41 (2004)... 

From the results, it can be concluded that HOLL canola oil is a good alternative to other commonly used oils for deep frying, with some advantages regarding nutritional aspects as well as the sensory quality of the oil and products. The low level of saturated fatty acids, no trans-fatty acids and the high content of oleic acid comparable to olive oil makes HOLL canola oil an attractive recommendation for the use in the preparation of deep-fried food. In addition, the results show that the... 

The influence of the oil type and quality on oil absorption and residues absorbed by fried foods is widely documented (e.g., Blumenthal, 1991 Blumenthal and Stier, 1991 Krokida et al., 2000 Nonaka et al, 1977 Pokomy, 1980). No relationship has been found between oil type and oil absorption however, it has been shown that an increase in the initial interfacial tension between oil and restructured potato products decreases oil absorption (Pinthus and Saguy, 1994). Further, as mentioned earlier, oil degradation produces surfactants that act as wetting agents, which also increase the absorption (Blumenthal, 1991). 

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