This study investigated the effect of NaCl (2 and 4% (w/v)) and vacuum impregnation (VI) (150, 200, 250, and 300 Pa) on the quality parameters (water uptake, elongation ratio, visual color, and texture), tocols, γ-oryzanol and phenolic compounds of parboiled rice. Parboiling with NaCl and VI resulted in increased lightness and higher concentrations of bioactive compounds than rice parboiled by the traditional method. The highest concentration of tocopherols, γ-oryzanol, and phenolic acids (syringic, and ferulic acids) were obtained from parboiled rice with NaCl concentration at 2% (w/v) and VI at 250 and 300 Pa. As the NaCl concentration and VI levels increased the hardness L*, b* and ΔE values also increased, but the a* value and water uptake decreased. Results suggested that NaCl-VI soaking was observed to be an effective method for parboiling which promoted the visual color and enhanced the concentration of bioactive compounds in the parboiled rice.

The objective of this study is to apply a response surface methodology in optimizing pulsed vacuum osmotic dehydration to achieve sufficient solids in a gel matrix using a diluted solution. Its application for enrichment of antioxidant compounds and nutrients is also investigated. The process variables are agar-gel bulk density (0.65-0.85 g/ml), sucrose concentration (30-60% w/w) and vacuum impregnation time (10-30 min). The results show that process variables, especially sucrose concentration, significantly affected moisture content (MC), water loss (WL) and solids gain (SG) of a model food. A quadratic model was fitted for WL, SG, weight reduction and total soluble solids prediction (). The prediction of total soluble solids was the most precise (). Optimum conditions were 32.58%w/w for sucrose content, 0.8 g/ml in bulk density and 14.34 min vacuum time. The physiological compounds can be sufficiently introduced into the model food with a diluted solution. The results may be applied to the development of new innovative products that provide the desired compound level and functionality. This will increase product value, utilization of agricultural produce, and reduce the loss of freshness in seasonal produce, especially tropical fruits.

Soybean oil is beneficial from a nutritional viewpoint; however, the high concentration of polyunsaturated fatty acid presents a high risk of oxidation. This study incorporated α‐ and γ‐tocopherols and γ‐oryzanol as natural antioxidants from rice bran into soybean oil to improve oxidation stability of the oil using ohmic heating‐assisted ultrasound extraction. Moisturized bran (30% wet basis) was pretreated using an ohmic heater at 100 and 200 V/cm before ultrasound extraction using soybean oil as a green solvent. Raw and steamed rice bran extracted by ultrasound without ohmic heating were used as controls. Enriched soybean oil obtained from ohmic heating pretreatment gave the highest concentration of α‐ and γ‐tocopherols, γ‐oryzanol, and antioxidant activities with low concentrations of free fatty acids, thiobarbituric acid, and peroxide values. Results suggested that ohmic heating‐assisted ultrasound extraction showed potential to enrich soybean oil with bioactive compounds. Practical applications Soybean oil can be enriched with tocols and γ‐oryzanol from rice bran to increase oil quality and oxidative stability. Ohmic heating was applied to assist ultrasound extraction of tocols and γ‐oryzanol from rice bran. Extraction of edible vegetable oils using ohmic heating‐assisted ultrasound is an alternative green process to improve oil quality and produce functional vegetable oils enriched with value‐added compounds.

Soybean oil enrichment with tocols and γ-oryzanol from rice bran using ohmic heating-assisted ultrasound extraction with soybean oil a green solvent was investigated. Moisturized bran (30% wet basis) samples were ohmically-treated at 100 and 200 V/cm and then subjected to ultrasound extraction using soybean oil a green solvent. Untreated rice bran and bran steamed with an autoclave before ultrasound extraction with soybean oil were used as controls (UB-UASO and CB-UASO). Ohmic heating applied to assist ultrasound soybean oil extraction (OH-UASO) gave higher yields of α- and γ-tocopherols and γ-oryzanol compared to UB-UASO and CB-UASO. Enriched oil obtained by OH-UASO also gave the highest antioxidant activities (DPPH, FRAP and total antioxidant capacity assays), with low concentrations of free fatty acids, thiobarbituric acid (TBA) and peroxide values (PV) during storage for 28 days. Production of edible vegetable oils as a green solvent containing high tocols and γ-oryzanol was achieved, with improved efficiency through ohmic heating.