Designing a Smart Contract-Based Decentralized Marketplace for Vegetarian Food Supply Chains: Pilot Evaluation of VegeChain in Indonesia

Vegetarian food supply chains in Indonesia are constrained by fragmented intermediation, opaque quality information and slow settlement, which erode producer margins, weaken consumer confidence and slow the adoption of plant-forward dietary programmes such as Meatless, Balanced, Green (MBG). This study designed, prototyped and evaluated VegeChain, a decentralized marketplace in which Ethereum-compatible smart contracts execute automated market maker pricing with perishability-aware time decay, sensor-assisted quality verification, reputation-weighted trust scoring and escrow-based settlement. A design science research process combined architecture design, mathematical modelling of multi-objective supply chain efficiency, and empirical validation through a 90-day pilot in 12 Indonesian districts with 456 supply chain stakeholders, complemented by load testing with 25,000 concurrent users. Relative to the conventional multi-tier chain, the prototype improved supply chain efficiency by 35%, reduced transaction costs by 34% and food waste by 28%, shortened payment cycles from 42 to 3 days, raised end-to-end traceability from 12% to 97% and increased consumer trust by 42% (p < 0.001). The Byzantine fault tolerant consensus sustained 99.1% accuracy under peak load, gas optimisation lowered execution costs by 67% and quality verification reached 98.3% accuracy. The results provide a reference architecture and deployment roadmap for blockchain-enabled vegetarian food markets.