Effects of Radio Frequency Heating on the Stability and Antioxidant Properties of Rice Bran

Abstract

Radio frequency (RF) technology is considered as a rapid heating method. Lipase in rice bran could highly accelerate lipid oxidation. The objectives of this study were to establish the radio frequency heating conditions for lipase inactivation and to evaluate the stability and antioxidant capacity. The results showed that the suitable electrode gap for a 1 kg sample load was 6 cm, and it only took 2 min to heat rice bran from 25 °C to 100 °C. Besides, there were no significant differences in the total phenolic content, flavonoid content and color between the untreated and RF-treated group, and the DPPH free radical scavenging activity of the RF treatment reached 84.8%. The acid value, free fatty acid content and peroxide value of the RF-treated rice bran met the quality standard after 8 weeks of storage at 4, 25 and 37 °C. In summary, this study provides valuable information about the RF heating procedure, and shows the great potential of RF technology for stabilizing rice bran efficiently.

Influence of Radio Frequency Heating on the Pasteurization and Drying of Solid-State Fermented Wolfiporia cocos Products

“…The RF-dried soybean residue [ 6 ] and RF-stabilized rice bran [ 7 ] were mixed as a 1:1 ratio to form a solid-state medium (40% moisture content) in a plastic bag, and then sterilized in a 121 °C autoclave. After cooling, 10 mL of the pre-activated W. cocos solution was inoculated into 500 g of the solid-state medium and cultured for 30 d at 25 °C in an incubator.…”

“…The color of sample was measured according to Chen et al [ 7 ] with a color difference meter and standardized against a calibration white plate (X = 82.48, Y = 84.23, Z = 99.61; L* = 92.93, a* = − 1.26, b* = 1.17). The parameters determined were the degrees of lightness (L*), redness (+a*) or greenness (−a*), and yellowness (+b*) or blueness (−b*).…”

“…The biofunctions of W. cocos include tumor inhibition [ 2 ], immunity improvement [ 3 ], and anti-inflammatory, antiaging, hypoglycemic [ 4 ], hypolipidemic, antibacterial [ 5 ], and antioxidant capacities. Soybean residues from soybean milk production can be rapidly dried by radio frequency (RF) energy [ 6 ], and rice bran from milled brown rice can be stabilized by RF heating [ 7 ]. When soybean residues and rice bran are mixed in a 1:1 ratio to form a solid-state medium for W. cocos fermentation, the cost of the process is reduced and a mycelial product rich in polysaccharides and triterpenoids is produced.…”

Tempering–preservation treatment inactivated lipase in wheat bran and retained phenolic compounds

“…However, an augmentation of free polyphenols and a decrease of bound polyphenols were observed after rice bran stabilisation using drum drying (Saji et al ., 2020). Radio frequency heating was regarded as a good treatment for stabilisation because it did not change the total phenolic content of rice bran (Chen et al ., 2021). Thus, the phenolic compounds in wheat bran during stabilisation treatment should be investigated.…”

Editorial Overview on Emerging Thermal Food Processing Technologies

“…A manuscript on “Effects of Radio Frequency Heating on the Stability and Antioxidant Properties of Rice Bran” explored the applicability of Radio Frequency to inactivate lipase of rice bran that accelerates lipid oxidation leading to product deterioration [ 4 ]. This study provides promising outcomes regarding the potential of this emerging technology for rice bran stabilization.…”