Improving oil stability in deep-fried snack production: A case study

Oil degradation occurs rapidly in the deep-frying process, which compromises food quality and food safety. Oil blending can be used to improve stability. An experiment using a Rancimat at 190°C with 10 L/h airflow for 30 min followed with total polar material content (TPM) and free fatty acid content (FFA) tests were conducted to select blend candidates for full-scale production trials. Rapeseed oil (RO) blended with 25% rice bran oil (RBO), hazelnut oil (HO), and red palm oil (RPO), respectively, and high oleic sunflower oil (HOSO) blended with 25% RO, RBO, respectively, were tested. In a crisp production trial using an industrial continuous fryer, HOSO-RO blended with 15% RO had no negative impact on the oil stability and product quality. In a hand-cooked crisp production trial using industrial batch fryers, regular sunflower oil (RSO) blended with 15% RBO reduced free fatty acid (FFA) accumulation in oil with no negative impacts on product quality. Practical applications: Food manufacturers in the UK producing fried products often have to use high oleic sunflower oil (HOSO) for its high oxidation stability. However, HOSO is expensive and its supply relies on imports. In this work, we have demonstrated the feasibility of using rapeseed oil (RO) as a blending ingredient in HOSO in the production of crisps to reduce cost and improve supply chain resilience, without compromising processing stability and product quality. We also found rice bran oil has considerable potential to be used as a blending ingredient to improve the processing stability of frying oils.