Sheepskin gelatin-based edible film: the use of soybean oil as a plasticizer

Abstract

This study aimed to develop edible films based on sheepskin gelatin, incorporating soybean oil as a plasticizer. Treatment was divided into three groups, namely GO1, GO2, and GO3, each containing soybean oil at 0%, 2.5%, and 5% (v/v). A homogenizer was used to combine gelatin from sheepskin and soybean oil. Then, ultrasound was applied to form edible films. The results showed that adding soybean oil increased the films thickness, opacity, water resistance, and moisture content. However, it decreased the transparency and swelling of the films. It also did not affect the water activity of the films. The GO3 sample had the highest L* value, a*, and b* values. It also had the lowest ∆E value, which indicated that it was close to the color of the original material. The peak wavenumbers changed after adding soybean oil, especially in the amide A and fingerprint regions. A notable shift occurred at the peak wavenumber of 1744.94 cm⁻¹, which represented the vibrational stretching of C=O in triglycerides. The produced edible film had low flexibility, but it serves as a valuable reference for developing safe and practical films using gelatin sheepskin with natural oils as plasticizers.