Preservation of oleic acid entrapped in a condensed matrix of high-methoxy pectin with glucose syrup

The effect of mechanical glass transition temperature on the oxidation rates of omega fatty acids in condensed biopolymer matrices

The concept of glass transition has been used in food products to study their stability, extending shelf life and enhancing organoleptic desirability. This investigation evaluates the effect of three-dimensional structure as a barrier to oxidation of omega fatty acids in condensed hydrocolloid-based matrices. Two high-solid preparations were employed: κ-carrageenan with glucose syrup and genipin-crosslinked gelatin with polydextrose. They supported discontinuous microscopic inclusions of linoleic and linolenic acids within the rubber-to-glass transition region of the condensed mixtures. Glass transition temperatures (Tg) were estimated using differential scanning calorimetry and in-shear dynamic oscillation. The rate of lipid oxidation was monitored by analysing hydroperoxide (ROOH) production during each oxidation phase. The structural transformation of the supporting matrices as a function of temperature significantly affects the oxidation processes. The mechanical or network Tg exhibited higher values than the calorimetric Tg, supporting reduced lipid oxidation rates by suppressing ROOH accumulation in the densified glassy matrices.

The effect of ultrasonic power on the physicochemical properties and antioxidant activities of frosted figs pectin

Ultrasound has been widely used in industry due to its high energy and efficiency. This study optimized the ultrasonic-assisted extraction (UAE) process of frosted figs pectin (FFP) using response surface methodology (RSM), and further investigated the effect of ultrasonic power on the structural characteristics and antioxidant activities of FFPs. The UAE method of FFP through RSM was optimized, and the optimal extraction process conditions, particle size of 100 mesh, pH value of 1.95, liquid-solid ratio of 47:1 (mL/g), extraction temperature of 50 °C and extraction time of 65 min, were obtained. The extraction rate of FFP under this condition was 37.97 ± 2.56 %. Then, the four FFPs modified by ultrasound were obtained by changing the ultrasonic power. Research had found that ultrasonic power had little effect on the monosaccharide composition, Zeta potential, as well as the thermal stability and appearance structure of the four FFPs. However, ultrasonic power had a significant impact on other properties of FFP: as the ultrasonic power increased, the DM% and particle size decreased continuously, while the total carbohydrate content increased. Meanwhile, ultrasonic power also had a significant impact on antioxidant activities of FFPs. From the research results, it could be seen that different ultrasonic power had certain changes in its spatial structure and properties, and the structural changes also affected the biological activity of FFP. The study of the effects of ultrasonic power on the physicochemical properties and biological activity of FFP lays the foundation for the development and application of FFP in food additives and natural drug carriers.