Insights into the effects of multiple frequency ultrasound combined with acid treatments on the physicochemical and thermal properties of brown rice postcooking

• Published in: Food science & technology Vol. 188; p. 115423
• Main Authors: Lin, Yu-Wen, Tsai, Chian-Lin, Chen, Chung-Jen, Li, Pei-Lin, Huang, Ping-Hsiu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023
• Subjects: Brown rice; Heat moisture treatment; Hurdle technology; Multiple frequency ultrasound; Ready-to-eat; Ready-to-eat; Multiple frequency ultrasound; Heat moisture treatment; Brown rice; Hurdle technology
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2023.115423

This study was proposed to improve the taste of ready-to-eat rice by suitable organic acid addition with brown rice as the raw material and to investigate the effects of multiple frequency ultrasound combined with glucono-δ-lactone (GDL) on the physicochemical properties of brown rice grains under different treatment conditions, which included the moisture content, appearance, texture profile analysis (TPA) and microstructure of brown rice. This study showed that 2.2 g/100 mL GDL can reduce brown rice's pH < 4.6. Sensory evaluation revealed that its sour taste was similar to that of the control group (without acid), while it complied with the product specification for acidified canned food. The soaking brown rice for 30 min showed 23.3 g/100 mL moisture content, but the soaking process combined with multiple frequency (40/80 kHz) ultrasound at 200, 400, and 600 W enhanced the moisture content to 23.7–25.6 g/100 mL. This heat moisture treatment (HMT) improved the brown rice starch's modified thermal properties and texture while the optimal condition of 25.6 g/100 mL moisture content with multiple frequency ultrasound 400 W combined with 2.2 g/100 mL GDL was satisfactory for producing ready-to-eat brown rice with appearance integrity, improved brightness, and chewiness without unpleasant sourness. •Glucono-δ-lactone is an optional additive for producing ready-to-eat brown rice.•The novel method was developed by combining multiple food processing techniques.•Application and process improvement of low-acid canning product.