Formulation and shelf-life evaluation of protein-enriched energy bars from indigenous grains

Abstract:

Southern China's rural markets are flooded with imported protein bars made from refined oats and whey concentrate, yet the region grows a dozen indigenous grains—foxtail millet, sorghum, barnyard millet, buckwheat—that are nutritionally richer and far cheaper. This research formulated five protein-enriched energy bars from paired indigenous grain bases and evaluated their proximate composition, sensory acceptability, and shelf life at the South China Agricultural College, Guangzhou, from January to October 2023. Bars were stored at 25 °C and 37 °C (accelerated) and sampled monthly. Formulation F3 (foxtail millet–buckwheat with soy protein isolate) achieved the highest protein (18.2%), longest ambient shelf life (94 days to peroxide value limit), and acceptable sensory score (7.1/9). Formulation F5 (ragi–flaxseed) scored highest on sensory (7.6/9) but had a shorter shelf life (81 days) due to flaxseed lipid oxidation. All five indigenous-grain bars met the 15% protein threshold for a "high-protein" label claim. The F3 formulation is recommended for pilot-scale production targeting rural and urban snack markets in Guangdong.