Comparing nutritional levels in a commercially-available single-serve meal using microwave versus conventional oven heating. Issue 2 (2nd April 2020) - Brown, Eric F.
Abstract: Little published information exists examining the effect of heating methods on nutrient retention in single-serve frozen meals, which can have instructions for conventional and microwave ovens. In peer-reviewed references, there are no recent studies that address this question. This work compares the effect of two reheating methods on nutrient retention of a frozen single-serve meal that has dual conventional and microwave reheating instructions. The meal has a full range of nutrients that are either thermally labile or thermally stable. We hypothesized there would be parity in nutrient amounts in the meal between the two reheating methods. Nutrient composition was assessed by averaging results from 10 samples after three treatments: conventional oven reheating, microwave oven reheating, and unheated controls. Meals were reheated to a minimum of 74 °C per the package instructions and analysed for carbohydrate, protein, fat, sodium, potassium, vitamin A, vitamin C, vitamin E, thiamine, riboflavin, and folic acid. Nutrient changes were uniformly affected by reheating conditions, except for vitamin C. On average, microwaved meals retained 3.8 more milligrams vitamin C than meals heated in a conventional oven. Consumers can be confident that microwave reheating of frozen meals can result in equal nutrient retention as conventional oven reheating, and microwave reheating may result in slightly greater retention of vitamin C.