Enhanced Free Fatty Acid Production From Goat and Cow Milk: Conventional and Ultrasound-Assisted Lipolysis of Whole and Disrupted Fat Globules

Abstract

This work combined physical treatments to disrupt fat globules with the ultrasound-assisted enzymatic hydrolysis of goat milk cream (GMC) and cow milk cream (CMC) to improve free fatty acids production. Both creams were pretreated at 50°C by high shear dispersion (HSD-25 000 rpm/5 min), stirring (ST-4 min, 550 W) and high-pressure homogenization (HPH-40 MPa), resulting in a similar reduction in fat globule diameter for GMC (73%–83%, p > 0.05) and a greater reduction for CMC (87%) after HPH. The lipolysis was conducted using lipase with and without ultrasound (US) (20 kHz and 38.4 W/L) at 20°C–50°C for 300 min. The fatty acids concentration (FAC) over the reaction was quantified and modelled to determine the lipolysis rate and final FAC. Physical pretreatments increased lipolysis rate (2.6–3.9 times for GMC and 3.0–7.3 times for CMC) and FAC (7.8–10.1 times for GMC and 8.0–11.1 times for CMC) after conventional lipolysis. For GMC, the HPH = ST>HSD>control promoted higher final FAC. In contrast, for CMC, the order was changed to HPH>HSD>ST>control. For most conditions evaluated, especially at lower hydrolysis temperatures, US-assisted reactions promoted an additional increase in the final FAC (3%–73% for GMC and 2%–80% for CMC). Therefore, the physical disruption of fat globules is an interesting strategy to improve cream lipolysis, especially HPH and ST for goat cream and HPH and HSD for cow cream. In addition, US-assisted hydrolysis lowered the needed reaction temperature from 50°C to 20°C, possibly saving energy and reducing undesirable thermal impacts on the final product.

Practical applications: The findings highlight the potential of combining physical treatments and ultrasound-assisted lipolysis to enhance free fatty acid production from goat and cow milk creams. High-pressure homogenization and stirring proved effective for disrupting fat globules, while ultrasound-assisted hydrolysis further boosted lipolysis efficiency, particularly at lower temperatures. These strategies can be applied in the dairy and food industries to produce functional ingredients with tailored fatty acid profiles, improve the sensory properties of food products, and reduce energy consumption by enabling low-temperature processing. This approach also offers opportunities to develop innovative products with added nutritional and functional value.