Oleogel Modified Sodium Alginate Film With Improved Anti-UV, Water Vapor Barrier, Plasticity, and Antimicrobial Properties for Food Preservation.

Sodium alginate (SA) films are limited in practical application by inherent drawbacks, such as poor water vapor barrier performance, high brittleness, and susceptibility to microbial contamination. The incorporation of oleogel (OG) into SA films could simultaneously improve these deficiencies and endow the films with anti-UV ability. OG was fabricated using a gelator and cinnamaldehyde (CA). It had 3D network with physical barrier effect and displayed superior compatibility with SA through hydrogen bonding, thus achieving the sustained release of CA from the SA film matrix compared with the direct incorporation of free CA into the film. OG-modified SA film (SA-OG-1/3) and CA-modified SA film (SA-CA-1/3) were applied for the preservation of oranges. After 15 days of storage, the oranges treated with the SA-OG-1/3 film exhibited a fruit hardness of 10.65 N, weight loss rate of 3.24%, vitamin C (VC) content of 8.61 mg/100 g, and total viable count (TVC) of 249.00 CFU/g. By comparison, the SA-CA-1/3 group recorded corresponding values of 10.43 N, 3.35%, 7.90 mg/100 g, and 263.50 CFU/g, whereas the untreated control group showed 9.18 N, 3.75%, 1.69 mg/100 g, and 502.50 CFU/g, respectively. These results demonstrated that the SA-OG composite film possessed the optimal capacity to delay the spoilage of oranges. We anticipate that this study could provide insight into practical application of SA composite film in food preservation industries.