Stability of rice bran oil extracted by SFE and soxhlet methods during accelerated shelf-life storage

Improving the quality properties of soybean oil by using rice bran oil

This study aims to study the effect of substituting soybean oil (SO) with rice bran oil (RBO) at different levels (25%, 50%, and 75%) on the physical and chemical properties, fatty acid composition, and oxidative stability of SO, also, study the effect of storing SO, RBO, and their blend oils at ambient temperature for a period of 12 months on the content of free fatty acids (% FFA), peroxide value (PV), and thiobarbituric acid (TBA). RBO demonstrated good quality, as evidenced by its initial low values of % FFA, PV, and TBA. Furthermore, RBO was found to be an excellent source of γ-oryzanol, whereas the other oils lacked this compound. Consequently, increasing the proportion of RBO in SO resulted in the least degradation, while pure SO exhibited the highest degree of degradation. Moreover, the blend oils demonstrated an inhibitory effect against oxidation, allowing for a prolonged storage period without the use of industrial antioxidants. Throughout the entire storage period, the % FFA and PV of all tested blend oil samples remained within the limits recommended for human consumption. TBA exhibited a similar trend to PV. However, an incremental increase in TBA values was observed as the storage period of the oils extended. In SO, TBA levels increased from 0.533 mg malonaldehyde/kg oil at the beginning to 1.446 mg malonaldehyde/kg oil after 12 months of storage. In RBO, TBA levels increased from 0.336 mg malonaldehyde/kg oil at the beginning to 0.882 mg malonaldehyde/kg oil after 12 months of storage.

Effect of novel combination processing technologies on extraction and quality of rice bran oil

Rice bran, a primary by-product from the rice processing industries, containing 10-15% oil, attracts significant attention from consumers due to its many health-promoting effects. The extraction methodology used is one of the most critical factors affecting the quality and yield of oil from rice bran. Using solvents is the current commercial process for rice bran oil extraction, which has its setbacks. It is challenging and expensive, and there is a risk of traces of solvent residue in the oil. Emerging combination extraction technologies offer zero to minimal solvent residues or chemical deformation while considering increasing environmental and energy footprint. Emerging combination processing technologies include new-age methods like supercritical fluid extraction, sub-critical fluid extraction, ultrasound-assisted enzymatic extraction, ohmic heating, and microwave-assisted extraction. These techniques have been reported to extract oil from rice bran, improving extraction efficiency and quality. These techniques demonstrate solid prospects for future applications. The present review discusses and compares these emerging technologies for oil extraction from rice bran commercially.

Study of the thermal stability of γ-oryzanol present in rice bran oil over time

BACKGROUND

Rice bran oil is unique among edible oils owing to its rich source of commercially and nutritionally important phytochemicals, such as oryzanol. γ-Oryzanol performs an important role in the stability of rice bran oil. The crude rice bran oil obtained by solvent extraction is subjected to either chemical or physical refining to meet the specifications of edible-grade vegetable oil. These refining processes can cause the compounds present in rice bran oil to degrade. The aim of this study was to evaluate the stability of γ-oryzanol present in chemically and physically refined rice bran oils, when submitted to temperatures of 100, 140, and 180 °C for a period of 1368 h.

RESULTS

The chemically refined rice bran oil presented a lower γ-oryzanol content than the physically refined rice bran oil at all heating temperatures. The losses of γ-oryzanol at 100 °C, 140 °C, and 180 °C at the end of the heating periods for the chemically refined oil were 53.47%, 58.48%, and 97.05% respectively, and for the physically refined oil the losses were 38.11%, 53.58%, and 91.11% respectively.

CONCLUSION

Based on the results of the time to reduce the oryzanol concentration by 50% and 100%, it is observed that the oil of rice meal refined physically presents greater stability, in the different temperatures studied and over time, than the oil of rice meal refined chemically. Thus, for situations where the oil needs to be subjected to prolonged heating, a temperature of 100 °C is indicated. In this condition, the physically refined oil is better for maintaining a higher concentration of γ-oryzanol. © 2021 Society of Chemical Industry.

Supercritical Carbon Dioxide Extraction, Antioxidant Activity, and Fatty Acid Composition of Bran Oil from Rice Varieties Cultivated in Portugal

Bran of different rice cultivars produced in Portugal were used to study supercritical carbon dioxide extraction conditions of rice bran oil (RBO) and evaluate and compare antioxidant activity and fatty acid composition of the different rice bran varieties. The effect of plant loading (10–20 g), CO2 flow rate (0.5–1.5 L/min), pressure (20–60 MPa), and temperature (40–80 °C) was studied. The amount of oil extracted ranged from 11.72%, for Ariete cultivar, to 15.60%, for Sirio cultivar. The main fatty acids components obtained were palmitic (13.37%–16.32%), oleic (44.60%–52.56%), and linoleic (29.90%–38.51%). Excellent parameters of the susceptibility to oxidation of the oils were obtained and compare. RBO of Ariete and Gladio varieties presented superior DPPH and ABTS radical scavenging activities, whereas, Minima, Ellebi, and Sirio varieties had the lowest scavenging activities. Moreover, the oil obtained towards the final stages of extraction presented increased antioxidant activity.

Comparative Studies between Conventional and Microwave Assisted Extraction for Rice Bran Oil

The present work deals with comparison of microwave assisted extraction to that of conventional solvent extraction for the extraction of rice bran oil (RBO); focusing on extraction yield and oil composition. Microwave assisted extraction act as a green process over other method and proved that it is effective method for extraction of oil. The investigation also focuses on the study of functional group and component present in oil. Natural antioxidant component; its activity was confirmed by DPPH assay. The oryzanol content was also determined by measuring the optical density of the sample at 315 nm in n-heptane using UV visible spectrophotometer.

Supercritical CO2 Extraction of Rice Bran Oil -the Technology, Manufacture, and Applications

Rice bran is a good source of nutrients that have large amounts of phytochemicals and antioxidants. Conventional rice bran oil production requires many processes that may deteriorate and degrade these valuable substances. Supercritical CO₂ extraction is a green alternative method for producing rice bran oil. This work reviews production of rice bran oil by supercritical carbon dioxide (SC-CO₂) extraction. In addition, the usefulness and advantages of SC-CO₂ extracted rice bran oil for edible oil and health purpose is also described.

Simultaneous quantification of vitamin E, γ-oryzanols and xanthophylls from rice bran essences extracted by supercritical CO2

Since the nutrition value of rice is diminished during rice processing, technology that can preserve and sustain functional compounds is necessary. In this study, supercritical carbon dioxide (SC-CO2) extraction was optimized for operational conditions (time, temperature, pressure and modifier) to extract vitamin E, γ-oryzanols and xanthophylls from rice bran. The simultaneous quantification of the compounds was developed using high-performance liquid chromatography with diode array and fluorescence detectors. Central composite design and respond surface methodology were applied to achieve optimum extraction conditions. The optimized conditions were 60min, 43°C, 5420psi with 10% ethanol as a modifier. Pigmented rice bran extracts contained greater amounts of functional phytochemicals than non-pigmented rice bran extracts (0.68, 1410, and non-detectable μg/g compared with 16.65, 2480, and 0.10μg/g of vitamin E, γ-oryzanols and xanthophylls in pigmented and non-pigmented ones, respectively). SC-CO2 extraction with modifier would be promising for preparation of phytochemical essences for therapeutic purpose.