Development of rapid, point-of-use dry chemistry dip-stick assays for food quality.

Oils and fats are essential nutrients for humans, providing fatty acids necessary for good health as well as being concentrated sources of calories. Fats enhance the taste, texture, and mouthfeel of many foods, and are functionally required in preparing a variety of food products. Frying in oil has been used as a cooking method for over 3,500 years, and has remained a popular way to prepare meals and snacks. However, as the populace becomes more educated and aware of the food they consume, fried foods have come under scrutiny due to their fat content and deleterious effects on health. With normal usage, frying oil degrades to form products that affect the taste and texture of the food, ultimately being discarded when it is "spent" and no longer suitable for cooking.We have developed a proprietary colorimetric technology that visually indicates the degradation of frying oil, changing from blue/black to yellow as the amount of total polar compounds (TPC) increases. These compounds are formed during the frying process, with a limit of 25% TPC being adopted in several countries. A high level of TPCs can cause the fried food to cook unevenly, absorb unwanted oil, and has shown to be deleterious to health. The level of TPCs in frying oil is considered to be the best indicator of its lifetime.Currently, the gold standard for measuring total polar compounds in frying fats is the American Oil Chemists' Society Official Method Cd 20-91 "Determination of Polar Compounds in Frying Fats". This is a laboratory-based method which requires special facilities, training, equipment, and takes approximately three hours to perform. Several hand-held conductivity tests have been developed to measure TPC, but are subject to interferences due to differences in types of fats and cost hundreds of dollars.We propose to complete the development of an inexpensive, easy-to-use dipstick prototype that measures % TPC and undergoes a drastic color change indicating when frying oils and fats should be discarded.Our preliminary work has produced a prototype dipstick which gives a very noticeable color change from 0% to 25% TPC. The work performed in Phase I will optimize this color change by evaluating several dye matrices, the effect of oil type, and by modifying the dye formulation. The objective of this work is to develop a convenient, inexpensive, and easy-to-use frying oil test which requires minimal training and undergoes a drastic color change with oils that are at the end of their usable life. This test will offer the fry operator a method for monitoring oil quality to improve taste, health, and alsoGoal 1: Evaluate several commercially-available glass fiber and/or polymer matrices to obtain the most robust formulation that will hold up to handling during manufacturing and also display the maximum color change when used in the assay.Goal 2: Modify the dye formulation, excipients, and synthesize new dye congener.Goal 3 Using a series of new and used oil samples standardized using the AOCS method, produce color charts correlating % TPC to end-point color for four commodity frying fats.Long-Term Objective: Create a suite of point-of-use tests which, with the aid of a portable cell-phone based instrument, measures the freshness and quality of food ingredients using chemical and/or immunosorbent assays converted to dipstick format.