Effect of thermal processing on the antioxidant activity of oilseeds used in bakery products: A systematic review

Thermal processing can affect the antioxidant activity of oilseeds which are often incorporated into bakery products or roasted on their own, subjecting them to high temperatures. To assess the effect of roasting, baking, and frying on the antioxidant activity of sunflower, pumpkin, poppy, flaxseed, and sesame seeds, a literature search was carried out in PubMed, Web of Science, and Scopus. 38 studies were included in the review. The outcomes varied between species. In most cases, the activity of sunflower seeds decreased (by 0.2–46.75 %), while the activity of pumpkin and sesame seeds increased (by 6.5–120.5 % and 3.6–456 %, respectively). The effect of thermal processing on the activity of flaxseeds was small, especially at temperatures below 150 °C. The effect of roasting on poppy seeds couldn’t be assessed due to insufficient data. The outcomes may vary for different cultivars or seeds grown in different regions; nevertheless, some species (e.g., pumpkin and sesame) can be recommended for procedures demanding high temperatures, while in others (e.g. sunflower) it should be avoided. Oilseeds with enhanced antioxidant activity could be used as functional foods or utilized in the pharmaceutical industry in the form of supplements, but more research is needed to ascertain their efficiency in vivo .