Flaxseed Cake Flour Incorporation into Ice Cream: Effects on Physicochemical, Rheological, Textural, and Melting Properties

Flaxseed press cake, a by-product of flaxseed oil production, has attracted growing interest as a food ingredient due to its nutritional composition. This study investigated the impact of partially replacing skim milk powder (SMP) with flaxseed cake flour (FCF) on the quality attributes of ice cream. Four samples were produced: a control and three formulations with SMP substituted at 25.0%, 37.5%, and 50.0%. The incorporation of FCF substantially modified the properties of both the ice cream mixes and the finished products. Apparent viscosity increased significantly from 0.25 Pa·s in the control to 1.86 Pa·s at maximum replacement, accompanied by a lower flow behavior index, indicating enhanced shear-thinning behavior. Although FCF addition reduced overrun and the fat destabilization index, it markedly altered textural parameters, resulting in higher hardness, cohesiveness, gumminess, and work of adhesion. This structural reinforcement was associated with improved melting resistance, as evidenced by an increase in the time to first drop, from 18.88 min (control) to 27.30 min (50.0% replacement), while the melting rate decreased from 2.22%/min to 1.66%/min. FCF caused pronounced changes in color, leading to lower lightness and greater redness compared with the control. Overall, partial replacement of SMP with FCF significantly altered the structural and technological properties of ice cream. These findings demonstrate the technological potential of flaxseed press cake flour as a structuring agent in frozen dairy matrices, offering a promising avenue for agri-food by-product valorization and innovative product development.