Effect of Bentonite Pre-Treatment on Growth Performance, Mineral Enrichment, and Antioxidant Properties of Soybean Sprouts

TL;DR

Bentonite pre-treatment improves soybean sprout growth, mineral content, and antioxidant properties, with optimal results at 1–3% concentrations.

Contribution

This study demonstrates that bentonite pre-treatment enhances soybean sprout nutritional and functional qualities in a concentration-dependent manner.

Findings

Bentonite at 1–3% increased sprout yield by up to 16.1% and vitamin C content by up to 18.91 mg/100 g FW.

Mineral content was significantly enhanced, with notable increases in phosphorus, potassium, copper, and iron.

Antioxidant properties and essential amino acids, including methionine and GABA, were significantly improved.

Abstract

Bentonite is a multifunctional material widely used in industry, agriculture, food processing, and medicine due to its strong binding and absorption properties. This study investigates the effects of bentonite pre-treatment at different concentrations (0.5–5%) on soybean sprout growth and nutritional quality. Moderate levels, particularly 1–3% (BP-1 and BP-3), significantly increased sprout yield (up to 16.1%) and vitamin C content (up to 18.91 mg/100 g FW), while maintaining desirable moisture and visual quality. Color evaluation showed higher yellowness (b*), suggesting improved consumer appeal. Mineral profiling indicated substantial enhancement of essential minerals across treatments, with the highest total mineral content recorded in the BP-5 group. Phosphorus, potassium, copper, and iron were notably enriched; however, elevated copper and reduced zinc at higher concentrations indicate potential nutritional risk. Isoflavone analysis revealed increased total isoflavones, especially glucoside forms such as daidzin and genistin, while aglycones like genistein decreased, reflecting bentonite’s selective influence on isoflavone metabolism. Antioxidant properties—including DPPH scavenging capacity, total polyphenols, flavonoids, and SOD-like activity—were significantly enhanced. Amino acid profiling also showed increases in essential amino acids, including methionine and valine, along with higher γ-aminobutyric acid (GABA). Overall, bentonite demonstrates strong potential as a natural additive for improving soybean sprout productivity and functional quality, with the most favorable outcomes observed at 1–3% concentrations.

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