A Rationale for Evaluation and Selection of Antioxidants for Protection of Ration Items of Different Types

摘要

Rancidity resulting from autoxidation of lipids (oxidation with atmospheric oxygen) in military ration items is a prime cause of rejection. Odor, color, flavor, and texture are degraded. For nearly fifty years scientists have searched for effective antioxidants and means of rating this effectiveness. For the first forty years fats and oils were the lipids scrutinized. These are triglycerides of varying composition and are usually an artefact food, being expressed or extracted from plant or animal tissue. Frying oils, salad oils, lard and butter are examples. They have a low surface to volume ratio (LSV) and usually a low water content. Antioxidants were chosen for effectiveness in fats and oils and rated by accelerated shelf life tests using dry bulk fat or oil: the so-called Active Oxygen Method (AOM), Schaal Oven Test, and Oxygen Bomb Test. An antioxidant was considered uniformly good or bad, judged by these tests, with little regard for appropriateness in other lipids. For the last twenty years, there has been growing attention to the protection of lipids dispersed in processed, whole tissue foods and in combination foods like baked goods, instant foods, and emulsions of the salad oil and whipped topping type. This has been hastened by people's desire for quickly prepared convenience foods like TV or airline dinners, largely precooked and predisposed to autoxidation. The first oxidizing lipids in these foods are often polar lipids, like the phosphatides of membranes, or alternatively, highly emulsified triglycerides as in baked goods or whipped toppings.