Evaluation of oven baking and air-frying as potential alternatives of deep frying, considering PM2.5 and PAHs emissions from cooking animal- and plant-based protein foods

Background

With most people spending more time indoors than outdoors, indoor pollution is considered having profound impacts on health. In Asian countries, high-temperature cooking oil fumes (COFs) are a major indoor air pollution source. Previous studies indicate variations in aerosol types and concentrations during deep-frying are attributed to differences in of ingredient composition such as foods cooked and oil used.

Objective

The goal is to compare PM_2.5 and polycyclic aromatic hydrocarbons (PAHs) emissions during deep-frying, oven-baking, and air-frying of plant-based (tofu) and animal-based (chicken) protein foods with soybean oil and to evaluate sensory acceptability of the produced foods in order to identify alternative cooking methods with lower emission but equivalent food tastes.

Method

We monitored emitted PAHs, PM_2.5, and particle size-specific mass and number concentrations of fine particles in eight replicates during cooking. Moreover, acceptance tests were conducted employing a nine-point Hedonic Scale regarding appearance, aroma, flavor, mouthfeel, aftertaste, and overall acceptance for different protein sources and cooking methods.

Results

Regarding particle matters, irrespective of the foods, deep-frying demonstrated higher particle mass and number concentrations compared to oven-baking and air-frying. Both mass and number concentrations for chicken were substantially higher than those for tofu, especially in the Accumulation mode and Aitken mode with diameters below 1000 nm. Tofu exhibited extremely low PAHs emissions across all cooking methods, while chicken showed significantly higher PAHs emissions during deep-frying than the other two cooking methods, with an accumulating effect over time. In sensory evaluation, although deep-frying still achieved the highest scores, oven-baking also received favorable ratings. It even surpassed deep-frying in certain aspects.