Influence of homogenization and pasteurization on the physical characteristics, antioxidant properties, and microbial content of VD20 rice milk

The preservation and stability of rice milk products are critical for their commercialization. This study focuses on the effects of homogenization and pasteurization on the stability and microbial safety of rice milk produced from VD20 broken rice, a variety cultivated in Go Cong, Tien Giang, Vietnam. Experiments were conducted by homogenizing the rice milk at four rotational speeds (6000, 8000, 10,000, and 12,000 rpm) for varying durations (5, 10, 15, and 20 min) and pasteurizing temperatures ranging from 80 °C to 95 °C. Homogenization was performed using an IKA T50 ULTRA-TURRAX^® homogenizer, and microbial counts were determined using standard plate count methods. The optimal processing conditions were identified as homogenization at 10,000 rpm for 15 min and pasteurization at 90 °C for 15 min, which ensured microbial safety (< 10⁵ CFU/mL) while preserving antioxidant activity (DPPH: 42.35 mgAAE/mL, ABTS: 39.01 mgAAE/mL) and polyphenol content (TPC: 78.55 mgGAE/mL). These findings contribute to optimizing the production and extending the shelf life of rice milk products, thereby enhancing the value of broken rice by-products and supporting the diversification of rice-derived functional beverages.