Effects of fat unsaturation degree on whipping performance and foam stability of fat‐reduced aerated emulsions

Summary Aerated emulsions formulated with vegetable oils have been widely consumed with health demands of tea‐based drinks and coffee. In comparison with its traditional counterparts consisting of 30%–40% of fats, that is, whipping creams, the aerated emulsions containing less than 20% vegetable oils are classified as low fat‐cream‐like products and popular with consumers preferring fat‐reduced foods. However, unstable whipping capabilities are the typical quality defects of these low fat‐emulsions, which is highly related with partial coalescence of fat globules. In the present study, effects of unsaturation degree and fatty acid species of fat matrix on whipping capabilities of the aerated emulsions were evaluated by analysing crystal networks, partial coalescence behaviours, whipping performance, and foam structure and stabilities. Increase of fat unsaturation from 10% to 30% improved fat crystal structure and partial coalescence significantly. In particular, 10%–15% of medium chain‐fatty acids present in the emulsions with 30% unsaturated fats tended to crystallise into well‐packed thicker crystals, and to exhibit the highest partial coalescence rate with nearly 60% of solid fat content at whipping temperature. Both the fat species and unsaturation contributed to forming smooth appearance and desirable foam networks after whipping. In contrast, further increase in unsaturation resulted in significant reduction of adsorbed proteins, contributing to excessive aggregation of fat globules. Therefore, it presented negative effects on partial coalescence as well as foam firmness and stabilities. The results figured out characteristics of fat matrix for the manufacture of low fat‐aerated creams with improved whipping capabilities.