Research Projects

Frying is a unit operation and one of the most widely used dehydration methods in the small and large-scale snack food industries to develop fried savoury snack products such as chakli, boondi, kadbole, sev and bhujia. Deep fat frying or conventional atmospheric frying carried out at high temperature above 170°C is essential for developing desirable textures and flavors in these savoury snacks. However, high temperature frying causes various changes in both the oil and the product. The oil uptake is the characteristic feature, which makes fried savoury snacks rich in calories. Besides, frying degrades nutrients, bioactive compounds, oil quality and also leads to the formation of carcinogenic compounds like Acrylamides (cancer causing carcinogen) which are risk factors for various health issues. Vacuum frying has emerged as a potential alternative, particularly for fruit and vegetable snacks, as it allows frying at lower temperatures under reduced pressure. This method helps retain more nutrients, reduces oil absorption and minimizes the degradation of bioactive compounds. However, vacuum frying is not suitable for many traditional savory snacks, particularly dough-based items like chakli, kadbole, and sev, or batter-based products such as boondi. These foods tend to lose their structural integrity under vacuum conditions and may disintegrate. Moreover, introducing dough and batter-based foods directly into a vacuum fryer poses additional challenges, such as vacuum loss and inconsistent product shape. Field trials of a mini vacuum fryer (Patent Application No. 202441010331) developed with DST-NIDHI PRAYAS grant support, revealed the limitations of vacuum frying for traditional or atmospheric fried savory snacks and underscored the importance of a two-stage fryer capable of minimizing oil absorption while preserving shape and quality. To overcome the limitations of both deep-fat frying and vacuum frying, a two-stage frying method presents a promising alternative. This method involves initial atmospheric frying at high temperatures for less than one minute to form a stable crust, followed by vacuum frying at lower temperatures to reduce oil absorption. This approach helps retain the shape of savory snacks, minimize oil uptake, and preserve bioactive compounds effectively. The objective of this proposal is to design and develop a two-stage fryer specifically adapted to produce healthier savoury snack products that maintain their structural integrity, retain bioactive compounds and maintain oil quality. This innovative continuous two-stage frying solution represents a significant advancement, enabling the food industry to meet health-conscious consumer demands while optimizing production efficiency and product shelf life.