OMB_Meeting_Book-11-2016

AOAC OMB Teleconference Materials

163

This industry/academia project was the first instance of Rutgers University’s being a paid subcontractor to a private research company, and required a new type of contract.

Descriptions of major work

A New Paradigm of Deep-Fat Frying Deep-fat frying is one of the most widely used methods of food production, and is practiced all over the world. It is a $75 billion a year industry in the U.S. alone, and estimated to be twice that worldwide. An extremely wide variety of types of foods are fried and oil blanched, and frying fats and oils are valuable and ever-more-costly agricultural commodity products. Extensive research is being done in the U.S. and abroad on new oilseed varieties, genetically enhanced oils, and processes and procedures to improve the nutritional profile, stability, and other important properties of fats and oils used for food, and, in particular, for deep frying. In addition, the quality, safety, nutritional and aesthetic values of many agricultural products - the foods fried - are affected significantly by the frying process. The proper conduct of frying operations is essential for food quality, safety, nutrition, and economics. Until now, it has been largely an art. Dr. Michael Blumenthal has developed a powerful new scientific understanding of the dynamic forces and factors that affect frying processes, and his research has led to a new paradigm. He has approached the problem of the degradation of edible fats and oils during frying processes from a physical chemistry / engineering / systems perspective, focusing on heat and mass transfer, going beyond the traditionally-studied organic chemistry of frying oils. His research explores the entire frying system and the interactions between frying fats/oils and the foods fried, the equipment and processing aids used, ingredients coming in, and the complex chemistry at work between the heated surfaces, the degrading oil, leachates from the food, entrained and reactive oxygen, and the constantly changing surface and interior of the dehydrating food. Dr. Blumenthal has proposed (and subsequent research has confirmed) a new paradigm of surfactancy as the mediator of heat transfer between frying oil and largely aqueous food. The theory states "Surfactants are responsible for the surface and interior differences in fried foods, as induced by aging oils." Using the systems approach and analyzing thousands of samples, Dr. Blumenthal's laboratory established a large database from which he deduced a simple mathematical relationship between the concentration of surfactants and the variations in food quality typically seen in food production and food service. Surfactants increase as oil is used and degrades. Control of surfactants enables proper cooking and optimization of food quality, food stability, oil economics, and system productivity. However, in degrading oil, as surfactant concentrations are increasing, leading to the oil "wetting" the food, the specific heat of the oil is increasing from that of fresh oil (linearly) with the accumulation of polymer species, which form due to oxidation and thermally abusive conditions. This increased specific heat causes poor cooking due to insufficient heat being available in the oil on the wetted surface. The formation and accumulation of smaller molecular species such as free fatty acid increases thermal conductivity, which factor controls the rate of replenishment of energy to oil at the food's surface. Without proper heat transfer into the interior of the food, even the microbial safety of fried foods such as chicken is compromised. The Gaussian curve that describes the relationship between the surfactant and polymer and other polar material concentrations and perceptible food quality has been named the Frying Quality Curve, and it portrays regions corresponding to initialization, normalization, optimization,

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11/09/2016