Production of rice bran oil (Oryza sativa L.) microparticles by spray drying taking advantage of the technological properties of cereal co-products.

Microparticles loaded with rice bran oil were produced by spray drying. Rice flour (RF) and rice protein (RP), considered as co-products of the cereal production chain, were tested as stabilizers in the encapsulation process to improve emulsion stability and the properties of the particles. Rice bran oil presented 1.75% É£-oryzanol, a powerful antioxidant with health benefits. AG/RP treatment (10% of rice protein): no phase separation after 24 h, higher zeta potential (-29.09 mV ± 0.67), encapsulation efficiency (73.90% ± 0.22), real density (1.27 g/cm-3), and smaller particle size (8.27 µm ± 0.13). Microparticles containing co-products were the most appropriate to slow down the autooxidation (at 60°C for 8 weeks), especially associated with the use of rice flour. The co-products improve the emulsion characteristics, particle properties and stability of the encapsulated oil. This study presented the technological effects of the use of rice chain co-products, which is in line with the current scenario of sustainability.

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.

Differences in the Compositions of Vitamin E Tocochromanol (Tocopherol and Tocotrienol) in Rice Bran Oils Produced in Japan and Other Countries.

In this study, we investigated the compositions of vitamin E tocochromanol [tocopherol (Toc) and tocotrienol (T3)] in crude and refined rice bran oil (RBO) produced in Japan and other countries, including Brazil, Thailand, and Vietnam, based on high-performance liquid chromatography analysis. All RBO analyzed contained α-, ß- and γ-Toc and α-, γ- and δ-T3. Japanese crude RBO, although not refined RBO, also contained ß-T3. Furthermore, total Toc contents in both Japanese crude and refined oils were found to be higher than those in the crude and refined RBO from other countries. Total T3 contents in Japanese crude RBO were similar to those in the crude RBO from Brazil and Vietnam. The α-Toc and α-T3 contents in Japanese crude and refined RBO were considerably higher than those in the crude and refined RBO produced in other countries, whereas in contrast, γ-Toc and γ-T3 contents in Japanese crude and refined RBO were lower. Consequently, the ratios of total α-Toc and α-T3 contents to total γ-Toc and γ-T3 contents in Japanese crude and refined RBO (1.75 and 1.91, respectively) were notably higher than those in the crude and refined RBO produced in other countries. Similarly, the ratios of total Toc to total T3 in Japanese crude and refined RBO were higher than those in the crude and refined RBO produced in other countries. These results accordingly indicate that the ratio of total α-Toc and α-T3 contents to γ-Toc and γ-T3 contents could be used as an effective index to discriminate between the RBO produced in Japan and that produced in other countries.

Improvement of Resveratrol Effects When Combined with Rice Oil in Rat Models of Inflammation.

This study investigated the effects of systemic treatment with a new formulation of resveratrol (RSV) vehicled in rice oil (RSVO) in experimental rat models of inflammation. Male Wistar rats were evaluated in the following in vivo models: carrageenan-induced acute edema, complete Freund's adjuvant (CFA)-evoked sub-chronic edema, and CFA-induced polyarthritis. The animals were treated orally with RSVO (10-15 mg/kg) or RSV (100-200 mg/kg), depending on the experimental protocol. RSV was more effective than RSVO in carrageenan-elicited acute edema when dosed in either prophylactic or therapeutic schemes of administration. However, the repeated RSVO administration, at 10-fold lower doses, exhibited superior anti-inflammatory actions in either the sub-chronic edema or the chronic polyarthritis model elicited by CFA, when compared with RSV. The novel formulation RSVO displayed a lower plasma biotransformation when compared with the RSV-treated group-46% versus 88% of metabolites, respectively. RSVO also prevented polyarthritis-related cartilage destruction, an effect that might rely on the inhibition of the pro-inflammatory cytokine interleukin-6 (IL-6), associated with an increase of the anti-inflammatory cytokine interleukin-10 (IL-10). Noteworthy, the long-term administration of RSVO did not elicit any gastrointestinal harm. Our study revealed that RSVO was notably effective in the long-term inflammatory and degenerative responses triggered by CFA. This innovative formulation might well represent a promising alternative for treating chronic inflammatory diseases, such as arthritis.

Stabilization of Rice Bran in Broiler Feed with Natural and Synthetic Antioxidants and Heat Treatment

The objective of this study was to evaluate different strategies for the oxidative stabilization of rice bran (RB) in the diet of broiler chickens using natural antioxidant additives, synthetic antioxidant additives and heat treatment on performance, breast meat quality and liver fat content and the nutrient digestibility coefficients. Furthermore, the study aimed to evaluate the effects of heat treatment and antioxidants, antioxidant additive treatments, without antioxidants, natural, and synthetic, and to three heat treatments, without heat, dry-heat and moist-heat, after the rice bran was stored for 90 days and then incorporated into the experimental diets. 1080 broilers were arranged in a 3 x 3-factorial randomized design with 10 replicates per treatments. The wet heat treatment of the meal resulted in a higher daily feed intake and body weight at 28 days and better feed conversion than did the meal without heat treatment. No significant interactions were observed between the tested factors on the apparent digestibility of dry matter and ether extract as well as the values of apparent metabolizable energy and apparent metabolizable energy corrected for nitrogen. However, there was significant interaction between the tested factors on the nitrogen retention coefficient; the natural antioxidant and dry heat-treated meal combination presented a lower crude protein digestibility coefficient than those without heat treatment. In conclusion, thermal treatment of this bran proved to be more effective as demonstrated by the performance responses of the birds. Broiler chickens reared up to 28 days of age consuming diets containing 6.5% RB stabilized by heat treatment showed better performance, and the use of antioxidants was not necessary.

Stabilization of Rice Bran in Broiler Feed with Natural and Synthetic Antioxidants and Heat Treatment

The objective of this study was to evaluate different strategies for the oxidative stabilization of rice bran (RB) in the diet of broiler chickens using natural antioxidant additives, synthetic antioxidant additives and heat treatment on performance, breast meat quality and liver fat content and the nutrient digestibility coefficients. Furthermore, the study aimed to evaluate the effects of heat treatment and antioxidants, antioxidant additive treatments, without antioxidants, natural, and synthetic, and to three heat treatments, without heat, dry-heat and moist-heat, after the rice bran was stored for 90 days and then incorporated into the experimental diets. 1080 broilers were arranged in a 3 x 3-factorial randomized design with 10 replicates per treatments. The wet heat treatment of the meal resulted in a higher daily feed intake and body weight at 28 days and better feed conversion than did the meal without heat treatment. No significant interactions were observed between the tested factors on the apparent digestibility of dry matter and ether extract as well as the values of apparent metabolizable energy and apparent metabolizable energy corrected for nitrogen. However, there was significant interaction between the tested factors on the nitrogen retention coefficient; the natural antioxidant and dry heat-treated meal combination presented a lower crude protein digestibility coefficient than those without heat treatment. In conclusion, thermal treatment of this bran proved to be more effective as demonstrated by the performance responses of the birds. Broiler chickens reared up to 28 days of age consuming diets containing 6.5% RB stabilized by heat treatment showed better performance, and the use of antioxidants was not necessary.(AU)

Efficacy of energy supplementation on growth performance and immune response of suckling pigs.

Three studies were performed to determine the effects of oral energy sources on the performance, immune status, and intestinal morphology of piglets. In Exp. 1, 50 litters were selected based on genotype and parity order to determine the optimum amount of supplemental energy for neonatal pigs. They were distributed according to a 5 × 5 Latin square design, in which columns were represented by 5 sows and rows were represented by 5 newborn weight categories. Treatments consisted of 2 oral doses of 0, 2, 4, 8, or 16 mL of rice bran oil (RBO). There was a positive response of RBO on BW with a numerical difference (P = 0.12) and a significant linear effect (P = 0.04) at weaning. In Exp. 2, litters (n = 340) were randomly allotted to a 2 × 2 factorial arrangement of treatments: RBO supplemented either through oral doses (without supplementation or with 2 mL of RBO) or through prestarter feed (without supplementation or with 2% of RBO replacing 2% of soybean oil). Piglets orally receiving RBO showed a numerical increase in BW at weaning (P = 0.101) compared with the control group. Moreover, piglets supplemented by prestarter feed tended to increase feed intake (P = 0.084). In Exp. 3, litters (n = 245) were selected based on genotype and parity order and they were distributed according to a 7 × 7 Latin square design planed in the same way as in Exp. 1. Each neonatal pig within a litter was randomly assigned to 1 of 7 treatments: 1) control (no supplementation), 2) 2 mL of RBO enriched with omega-3 fatty acids, 3) 2.33 mL of pure glycerin, 4) 1.3 mL of soybean oil, 5) 1.4 mL of linseed oil, 6) 1.68 mL of coconut oil, and 7) 2 mL of RBO. Animal performance was analyzed using 2 data sets: all data (average initial BW of 1.479 kg) and low birth weight (LBW) piglet data (≤1.220 kg initial BW with average of 0.985 kg). Body weight or BW gain (BWG) were not different among treatments (P > 0.10) when all data were analyzed. However, LBW piglets fed coconut oil tended to increase BW (P = 0.099) during the first week. In conclusion, the oral use of RBO may increase BW at weaning and the supplementation by prestarter feed may enhance the feed intake of piglets. In addition, coconut oil may increase BW of LBW piglets in the first week of life without affecting mortality, immune response, or gut morphology. The routine practice of oral supplementation of energy for newborn pigs could be an important tool in swine production.

Nanoencapsulation of rice bran oil increases its protective effects against UVB radiation-induced skin injury in mice.

Excessive UV-B radiation by sunlight produces inflammatory and oxidative damage of skin, which can lead to sunburn, photoaging, and cancer. This study evaluated whether nanoencapsulation improves the protective effects of rice bran oil against UVB radiation-induced skin damage in mice. Lipid-core nanocapsules containing rice bran oil were prepared, and had mean size around 200 nm, negative zeta potential (∼-9 mV), and low polydispersity index (<0.20). In order to allow application on the skin, a hydrogel containing the nanoencapsulated rice bran oil was prepared. This formulation was able to prevent ear edema induced by UVB irradiation by 60 ± 9%, when compared with a hydrogel containing LNC prepared with a mixture of medium chain triglycerides instead of rice bran oil. Protein carbonylation levels (biomarker of oxidative stress) and NF-κB nuclear translocation (biomarker of pro-inflammatory and carcinogenesis response) were reduced (81% and 87%, respectively) in animals treated with the hydrogel containing the nanoencapsulated rice bran oil. These in vivo results demonstrate the beneficial effects of nanoencapsulation to improve the protective properties of rice bran oil on skin damage caused by UVB exposure.

Effect of full-fat rice bran on palatability and digestibility of diets supplemented with enzymes in adult dogs.

Two experiments were conducted to evaluate the effect of full-fat rice bran (FFRB) inclusion in dry diets with and without enzyme blend (EB) supplementation for adult dogs. The diets contained 0, 20, or 40% of FFRB, replacing the equivalent amount of wheat flour (WF). Experiment 1 evaluated the consumption and preference of diets using a simple choice method with 3 comparisons (0 vs. 20, 0 vs. 40, and 20 vs. 40% FFRB). Experiment 2 investigated the effect of EB supplementation on the apparent digestibility coefficients (ADC) of nutrients and GE, fecal characteristics, urinary pH, Ca and P balance, and ME of the diets. In Exp. 1, the results indicated that FFRB included in diets up to 40% did not affect the preference or consumption of food by dogs (P < 0.05). In Exp. 2, increasing levels of FFRB in the diet linearly reduced the ADC of nutrients, GE, and ME (P < 0.05). The addition of EB had no effect on any of the variables examined. Regression analysis enabled estimation of the ADC in FFRB; and ADC of DM, CP, ether extract, GE; and the apparent coefficient of ME were 60.5, 74.8, 88.4, 70.8, and 66.4%, respectively. The inclusion of 20 or 40% FFRB in the diets did not affect urinary pH but caused an imbalance in the Ca and P metabolism when included at 40% (P < 0.05), which could be one of the limitations for greater inclusion of FFRB. The ME of FFRB was estimated to be 3,443 kcal/kg DM. The FFRB appears to be palatable for adult dogs, and although ADC was reduced by 40% FFRB in the diet, this ingredient has the potential for inclusion at 20% of diets for dogs, depending on the other ingredients used to achieve adequate Ca and P balance. The inclusion greater than 20% tends to increase P in the diet and reverse the relationship between Ca and P.

Influence of the type of vegetable oil on the drug release profile from lipid-core nanocapsules and in vivo genotoxicity study.

The use of rice bran (RB), soybean (SB) or sunflower seed (SF) oils to prepare lipid-core nanocapsules (LNCs) as controlled drug delivery systems was investigated. LNCs were prepared by interfacial deposition using the preformed polymer method. All formulations showed negative zeta potential and adequate nanotechnological characteristics (particle size 220-230 nm, polydispersity index < 0.20). The environmental safety was evaluated through an in vivo protocol (Allium cepa test) and LNCs containing RB, SB or SF oils did not present genotoxic potential. Clobetasol propionate (CP) was selected as a model drug to evaluate the influence of the type of vegetable oil on the control of the drug release from LNCs. Biphasic drug release profiles were observed for all formulations. After 168 h, the concentration of drug released from the formulation containing SF oil was lower (0.36 mg/mL) than from formulations containing SB (0.40 mg/mL) or RB oil (0.45 mg/mL). Good correlations between the consistency indices for the LNC cores and the burst and sustained drug release rate constants were obtained. Therefore, the type of the vegetal oil was shown as an important factor governing the control of drug release from LNCs.

γ-Oryzanol and tocopherol contents in residues of rice bran oil refining.

Rice bran oil (RBO) contains significant amounts of the natural antioxidants γ-oryzanol and tocopherols, which are lost to a large degree during oil refining. This results in a number of industrial residues with high contents of these phytochemicals. With the aim of supporting the development of profitable industrial procedures for γ-oryzanol and tocopherol recovery, the contents of these phytochemicals in all the residues produced during RBO refining were evaluated. The samples included residues from the degumming, soap precipitation, bleaching earth filtering, dewaxing and deodorisation distillation steps. The highest phytochemical concentrations were found in the precipitated soap for γ-oryzanol (14.2 mg g(-1), representing 95.3% of total γ-oryzanol in crude RBO), and in the deodorisation distillate for tocopherols (576 mg 100 g(-1), representing 6.7% of total tocopherols in crude RBO). Therefore, among the residues of RBO processing, the deodorisation distillate was the best source of tocopherols. As the soap is further processed for the recovery of fatty acids, samples taken from every step of this secondary process, including hydrosoluble fraction, hydrolysed soap, distillation residue and purified fatty acid fraction, were also analyzed. The distillation residue left after fatty acid recovery from soap was found to be the best source of γ-oryzanol (43.1 mg g(-1), representing 11.5% of total γ-oryzanol in crude RBO).

Formation and stability of oil-in-water nanoemulsions containing rice bran oil: in vitro and in vivo assessments.

BACKGROUND: Nanoemulsions have practical application in a multitude of commercial areas, such as the chemical, pharmaceutical and cosmetic industries. Cosmetic industries use rice bran oil in sunscreen formulations, anti ageing products and in treatments for skin diseases. The aim of this study was to create rice bran oil nanoemulsions using low energy emulsification methods and to evaluate their physical stability, irritation potential and moisturising activity on volunteers with normal and diseased skin types. RESULTS: The nanoemulsion developed by this phase diagram method was composed of 10% rice bran oil, 10% surfactants sorbitan oleate/PEG-30 castor oil, 0.05% antioxidant and 0.50% preservatives formulated in distilled water. The nanoemulsion was stable over the time course of this study. In vitro assays showed that this formulation has a low irritation potential, and when applied to human skin during in vivo studies, the nanoemulsion improved the skin's moisture and maintained normal skin pH values. CONCLUSION: The results of irritation potential studies and in vivo assessments indicate that this nanoemulsion has potential to be a useful tool to treat skin diseases, such as atopic dermatitis and psoriasis.