Preserving Soybean Oil for the Frying of Breaded Butterfly Shrimp Using Natural Rosemary Antioxidant.

Fried foods and frying oil are subjects that warrant the attention of researchers because of their high consumption. Indeed, frying conditions make these oils very sensitive to lipid oxidation which deteriorates the quality and nutritional properties of the food. In this study, we examined the effect of rosemary extract (ROE), known for its high antioxidant activity, in soybean oil used to fry breaded butterfly shrimp, by measuring the induction period with OXIPRES, total polar material (TPM), peroxide index (PI), and free fatty acids (FFA). This evaluation was performed in comparison with control oils without antioxidants. The results showed a significant difference between the oils according to the analyzed parameters, especially in the final hours of frying. The treatment of the oil with rosemary extract effectively delayed its oxidation, having lower levels in all the oxidation markers that were analyzed. It was also found that rosemary extract is able to reduce oil consumption by fried foods. Therefore, ROE ensures soybean oil a high stability against oxidation and a longer shelf life, making it a good natural alternative to synthetic antioxidants.

Crystal structure of 5-bromo-1-ethyl-indoline-2,3-dione.

The title compound, C10H8BrNO2, crystallizes with two independent molcules (A and B) in the asymmetric unit. In each mol-ecule, the indoline ring system is almost planar, with the largest deviation from the mean plane being 0.016 (2) Šin mol-ecule A and 0.040 (13) Šin mol-ecule B. In each mol-ecule, the ethyl group is nearly perpendicular to the indoline ring system with C-C-N-C torsion angles of -94.8 (3) and 93.0 (3)° in mol-ecules A and B, respectively. In the crystal, the two mol-ecules are inclined to each other, making a dihedral angle of 6.28 (8)°. In the molecular packing, the A and B mol-ecules are linked by C-H⋯O hydrogen bonds, forming -A-B-A-B- chains along [01-1]. Parallel chains are linked via a weak slipped parallel π-π inter-action [inter-centroid distance = 3.6107 (14) Å] and a short Br⋯O contact [3.183 (2) Å], forming a three-dimensional structure.