Optimization of Sweet Leaf (Sauropus androgynus L. Merr)–Amaranth (Amaranthus hybridus L.) Vegetable Leather With Carrageenan and Sorbitol

Abstract

Vegetable leather is an emerging preservation strategy that extends shelf life, reduces postharvest losses, and provides a convenient format for nutrient-rich vegetables. Sweet leaf (Sauropus androgynus L. Merr.) and amaranth (Amaranthus hybridus L.) are rich in bioactive compounds, making them promising raw materials for functional vegetable leather. This study optimized vegetable leather formulation by evaluating the effects of carrageenan, sorbitol, and sweet leaf–amaranth ratios on mechanical and physicochemical properties. Response surface methodology (RSM) with a D-optimal design was applied using Design Expert 13.0.12 software. Factors tested included carrageenan concentration (0.5%–2.5%), sorbitol concentration (1%–13%), and sweet leaf–amaranth ratios (25:75, 50:50, and 75:25). Optimization results identified the optimal formula as 0.877% carrageenan, 1% sorbitol, and a 25:75 sweet leaf–amaranth ratio, with a desirability value of 0.864. The optimized product exhibited tensile strength of 6.08 N/mm2, elongation of 6%, solubility of 92.77%, moisture content of 10.93%, and ash content of 3.11%. Functional analysis of the optimized product showed a chlorophyll content of 9.35 ± 0.35 mg·L−1 and antioxidant activity of 76.0 ± 0.02% inhibition. Sensory evaluation indicated neutral to slightly favorable acceptance, with overall acceptability of 5.1 ± 0.90 on a seven-point hedonic scale. These results confirm that the optimized sweet leaf–amaranth vegetable leather has promising functional and consumer attributes in addition to desirable physicochemical properties.