The Frying Stability of Oleogel Made from Rice Bran Wax and Sunflower Oil During Intermittent Frying of Potato Chips.

There is a need for an alternative method of producing a vegetable oil with high levels of unsaturated fatty acids and physical properties similar to solid fat. The objective of current work was to cut down the amount of oil absorbed by the finished product, increase the frying stability of sunflower oil, and fry potato chips using oleogel without harming their sensory quality. Rice bran wax was applied in this experiment, at rates of 2, 4, and 6 weight percent, and the generated oleogels were then utilized for four days in a succession to fry potato chips for four hours each day. The results suggested that potato chips could be fried using the sunflower oil-rice bran wax oleogel without having an adverse effect on their texture, color, or quality. Furthermore, the produced oleogel was more robust during frying than liquid sunflower oil. During intermittent frying, SFA levels also marginally rose in all samples with the exception of 4% oleogel. The control sample, which was sunflower oil, had the lowest levels of unsaturated fatty acids and poly unsaturated fatty acids at the end of the frying operation. The percentage of oil uptake by the potato chips in the oleogels containing 4 and 2% rice bran wax, on the other hand, was lower than in the control sample. The findings suggested that oleogels could be used as a deep-fat frying medium in household, commercial, and industrial settings.

Mechanical Properties and Friction Dynamics of Organogels Solidified with Rice Paraffin.

Raw materials suitable for a sustainable society have attracted interest in the cosmetics industry. We focused on rice bran as a sustainable material and evaluated the gelation behavior of paraffin extracted from rice bran (rice paraffin) against liquid paraffin, squalane, jojoba oil, and silicone oil. In addition, the frictional properties of the prepared organogel on an artificial skin surface were evaluated using a sinusoidal motion friction evaluation system. Rice paraffin solidified all oils even at the lowest wax concentration of 5 wt%. The hardness and kinetic friction coefficient µ k increased with an increase in the wax composition. The hardness and µ k of organogels solidified with rice paraffin were smaller than those of gels solidified with petroleum-derived paraffin. These differences are caused by the smaller carbon amount of rice paraffin. The friction parameters depended on the type of oil: the µ k of RLG composed of rice and liquid paraffin was greater than that of the other three oils (R, L, and G denote rice paraffin, liquid paraffin, and gel, respectively). These findings promote the development of lipsticks and cleansing gels consisting of sustainable development goal-responsive raw materials.

Construction of hemp seed protein isolate-phosphatidylcholine stablized oleogel-in-water gel system and its effect on structural properties and oxidation stability.

Rice bran wax was added to hemp seed oil (HSO) to prepare oleogel, and hemp seed protein isolate (HPI)-phosphatidylcholine (PC) was used as the emulsifier to obtain an oleogel-in-water (Og/W) gel system. The effect of HPI concentration on the construction of gel system was studied. Microscopic observations found that the oil droplets were encapsulated by the emulsifier. X-ray diffraction and Fourier transform infrared spectroscopy analysis showed that the increase in HPI concentration promoted the interaction between PC and protein, but didn't affect the crystal structure of gel. Thermogravimetric analysis showed that when the HPI concentration was 8 %, the sample formed a dense gel network and had good thermal stability. At this time, the oil holding capacity of gel was 98.81 ± 0.08 %, and the gel hardness was 109.55 ± 1.74 g. After 30 days of storage, the retention rate of Δ9-THC reached 96.3 %, and the peroxide value was 4.98 mmol/kg.

Assessment of physicochemical, functional, thermal, and phytochemical characteristics of refined rice bran wax.

The drastic increase in the utilization and conversion of biomass has been an effect of sustainability and circular economy in the food processing sector. Rice bran wax (RBW), an intermediate by-product of rice bran oil refining industries, has been one of the underutilized waste materials. The FT-IR analysis showed that RBW contains many similar compounds to that of beeswax (BW) and carnauba wax (CW). The DSC thermographs showed melting and crystallization temperatures of RBW as 78.55 and 73.43 °C, respectively, lesser than CW and more than BW. The peak profiling of XRD diffractographs has shown full-width at half-maximum of CW and RBW as 0.61 and 0.45, respectively, indicating distortion in crystal formation. The sequential extracts of RBW in hexane, dichloromethane, and ethylacetate have shown antimicrobial activity against E. coli and S. typhi. The research provides a baseline for extraction and separation of specialty compounds from RBW for by-product utilization.

Fabrication and characterization of the W/O/W multiple emulsion through oleogelation of oil.

W/O/W emulsions were easily prepared by oleogelation of the oil phase using rice bran wax (RBX) and their microstructure, stability, rheology and protection of proanthocyanidins and ß-carotene were investigated. Formation of the W/O/W emulsion was confirmed using confocal laser scanning microscopy and staining of the inner aqueous phase by tartrazine. The average particle size and viscosity of the emulsion increased as the RBX concentration increased. Moreover, RBX increased the stability of the emulsion and the emulsion was the most stable when the RBX concentration was 8.0% or 10.0%. On the other hand, the W/O/W emulsions were used to simultaneously encapsulate proanthocyanidins and ß-carotene. Specifically, proanthocyanidins and ß-carotene in RBX-containing emulsions were more stable and had higher bioaccessibility than in the emulsion without RBX. Besides, both their chemical stability and bioaccessibility reached the maximum value when the RBX concentration was 8.0% or 10.0%. In summary, the optimal RBX concentration was 8.0%.

Study of monoglycerides enriched with unsaturated fatty acids at sn-2 position as oleogelators for oleogel preparation.

The effect of using highly unsaturated 2-monoglycerides as oleogelators on the properties of soybean oil oleogels designed to eliminate saturated and trans fatty acids was investigated in this study. We adopted a novel two-step synthesis aiming to increase the yield of the 2-monoglycerides. The optimal synthesis conditions were a substrate weight ratio of 2:1 (w/w), 10% Lipozyme 435 (w/w total reactants), and 4 h of reaction time at room temperature. Under these conditions, the 2-monoglyceride yield (40.69%) increased by 10% compared to that of the conventional synthesis route. Additionally, soybean oil oleogels prepared using 10% 2-monoglycerides with or without rice bran wax were systematically characterized by polarized light microscopy, a texture analyzer, XRD spectroscopy, and rheometry. Comparative studies indicated that a combination of rice bran wax and 2-monoglycerides had synergistic effects on gel properties. A mixture of 4% rice bran wax and 6% 2-monoglycerides was found to provide better oleogels.

The Effect of Cooling Rate on the Microstructure and Macroscopic Properties of Rice Bran Wax Oleogels.

The main purpose of this paper is to study the microstructure and macroscopic characteristics of rice bran wax (RBW) oleogels at a cooling rate of 1°C/min and 10°C/min by polarized light microscopy, X-ray diffraction, differential scanning calorimetry, texture analyzer, and micro rheometer. The oleogels of soybean oil were prepared by RBW in concentrations of 5%, 7.5%, 10%, 15% and 20% (wt/wt). The results of this study indicated that the concentration of RBW and cooling rates were affected by the crystal size and spatial distribution of these crystals. For the same RBW concentration, oleogels contained smaller crystals when cooled at 10°C/min compared to 1°C/min. And the oleogels obtained at a rate of 10°C/min exhibited a tighter crystal network, lower melting point, harder texture, and energy storage modulus. These results demonstrated the impact of cooling rate on the rheological behavior, nucleation, and crystallization process.

Avaliação do desempenho de oleogéis estruturados com ceras vegetais como base lipídica reduzida em ácidos graxos saturados aplicados em cream cheeses / Performance evaluation of structured oleogels with vegetable waxes as a reduced lipid base in saturated fatty acids applied in cream cheeses

Diante das exigências crescentes das agências regulatórias do mundo todo quanto à redução/eliminação de ácidos graxos trans nos alimentos industrializados, bem como da conscientização do consumidor sobre a relação entre alimentação e saúde, o desenvolvimento de alternativas mais saudáveis aos óleos parcialmente hidrogenados e a outras fontes lipídicas com alto grau de saturaçã o se faz necessário. O oleogel, um sistema composto por um óleo preso em uma rede tridimensional formada por um agente estruturante, se apresenta como uma solução promissora. Dentre os diversos agentes estruturantes, as ceras vegetais se destacam por sua excelente capacidade de gelificação de óleos. Contudo, apresentam uma desvantagem sob o aspecto sensorial, pois podem conferir cerosidade e sabor residual desagradável aos alimentos. Com o objetivo de viabilizar o uso das ceras como agentes estruturantes em oleogéis face ao seu excelente desempenho tecnológico, este projeto propõe o estudo e a aplicação de oleogéis à base de óleo de soja (SBO) estruturado com ceras de farelo de arroz (RBW) a 2 e 4 % (m/m) ou carnaúba (CBW) a 3 e 6% (m/m), isoladamente. As matérias-primas foram caracterizadas e o comportamento de gelificação de cada cera foi avaliado por análises de textura por penetração de cone, estabilidade à perda de óleo por centrifugação, energia coesiva por parâmetro de solubilidade de Hansen (HSP) e comportamento de cristalização e fusão por calorimetria exploratória diferencial (DSC). Os resultados mostraram que ambas as ceras são capazes de formar oleogéis estruturalmente estáveis, contudo, o oleogel com 2% de RBW apresentou maior firmeza a 20 °C (190,4 gf/cm2) do que o oleogel com 6% de CBW a 5 °C (186,1 gf/cm2). Ao final de 5 dias, a capacidade de retenção de óleo do oleogel preparado com RBW foi de 100% às concentrações de 2 e 4% (m/m), contra 61 e 99,3% do oleogel elaborado com CBW às concentrações de 3 e 6% (m/m), respectivamente. Esses resultados podem ser explicados pela diferença entre as energias coesivas, ou seja, do grau de interação molecular entre o solvente e o soluto de cada oleogel. De acordo com os resultados de distância, que prevê se o gel formado será forte, fraco ou se não haverá formação de gel, o soluto CBW apresentou menor interação com o óleo (3,3 MPa1/2) do que o soluto RBW (3,7 MPa1/2). Os oleogéis foram aplicados como ingredientes em diferentes formulações de cream cheese, que foram analisados quanto a diferentes parâmetros de textura e esses resultados foram comparados a uma referência comercial. Nenhuma das amostras produzidas obteve resultados de textura estatisticamente iguais aos do cream cheese comercial (CC), o que pode ser explicado pelas diferenças de formulação e processamento dos produtos. Face aos resultados para textura e estabilidade à perda de óleo dos oleogéis de RBW, este agente estruturante apresenta ria maior potencial de aplicação, porém o oleogel CBW6 obteve alta capacidade de retenção de óleo (99,3%) e quando aplicado na formulação de cream cheese (CCBW6) apresentou resultados de firmeza e espalhabilidade mais próximos da amostra de referência, feita com gordura do leite (CMF)

Given the growing demands of regulatory agencies around the world regarding the reduction/elimination of trans fatty acids in processed foods, as well as consumer awareness about the relationship between food and health, the development of healthier alternatives to partially hydrogenated oils and others lipid sources with a high degree of saturation are necessary. Oleogel, a system composed of an oil trapped in a three-dimensional network formed by a structuring agent, presents itself as a promising solution. Among the various structuring agents, vegetable waxes stand out for their excellent oil gelling capacity. However, they have a sensory disadvantage, as they can give waxy and unpleasant aftertaste to foods. Aiming at enabling the use of waxes as structuring agents in oleogels in view of their excellent technological performance, this study proposes the evaluation and application of oleogels based on soybean oil (SBO) structured with rice bran wax (RBW) at 2 and 4% (m/m) or carnauba (CBW) at 3 and 6% (m/m). The raw materials were characterized and the gelling behavior of each wax was evaluated by analysis of texture by cone penetration, stability to oil loss by centrifugation, cohesive energy by Hansen solubility parameter (HSP) and crystallization and melting behavior. by differential scanning calorimetry (DSC). The results showed that both waxes are able to form structurally stable oleogels, however, oleogel with 2% RBW showed greater firmness at 20 °C (190.4 gf/cm2) than oleogel with 6% CBW at 5° C (186.1 gf/cm2). At the end of 5 days, the oil retention capacity of oleogel prepared with RBW was 100% at concentrations of 2 and 4% (m/m), against 61 and 99.3% of oleogel prepared with CBW at concentrations of 3 and 6% (m/m), respectively. These results can be explained by the difference between the cohesive energies, that is, the degree of molecular interaction between the solvent and the solute of each oleogel. According to the distance results, which predicts if the formed gel will be strong, weak or if there will be no gel formation, the CBW solute showed less interaction with the oil (3.3 MPa1/2) than the RBW solute (3 ,7 MPa1/2). Oleogels were applied as ingredients in different cream cheese formulations, which were analyzed for different texture parameters and these results were compared to a commercial reference. None of the samples produced had texture results statistically equal to those of commercial cream cheese (CC), which can be explained by the differences in formulation and processing of the products. Given the results for texture and oil binding capacity of RBW oleogels, this structuring agent would present greater application potential, but CBW6 oleogel obtained high oil biding capacity (99.3%) and when applied in cream cheese formulation (CCBW6) showed firmness and spreadability results closer to the reference sample, made with milk fat (CMF)

Stabilization of peanut butter by rice bran wax.

To improve stability of peanut butter, rice bran wax (RBX) was added into peanut butter as a stabilizer by formation of organogel. Effects of addition of RBX, heating temperature, and cooling temperature on stabilization effect of peanut butter by RBX were investigated. The optimum conditions were as follow: addition of RBX at 4.0 wt%; heating temperature at 85 °C, and cooling temperature at 20 °C. Under the optimum conditions, the oil loss of peanut butter decreased from 12.19% to 4.04%, and the adhesiveness of peanut butter increased from 23.5 to 165.9 g·s. After storage for 25 weeks, the acid value (AV) of peanut butter prepared under the optimum conditions increased from 0.65  to 0.80 mg/g, and the peroxide value (PV) increased from 0.116 to 0.127 meq/kg. However, the AV of natural peanut butter increased to 1.73 mg/g, and PV increased to 0.178 meq/kg. The confocal laser scanning microscope images showed that the cooling temperature significantly affected crystallization of RBX and distribution of solid particles. When RBX formed needle-like crystals and peanut solid particles were evenly distributed in the oil phase, stable peanut butter was obtained. These results suggested that the RBX was an effective stabilizer for peanut butter. PRACTICAL APPLICATION: Oil separation often occurred to peanut butter during storage, which reduced the sensory quality of peanut butter and shortened its shelf life. This study stabilized peanut butter by addition of RBX based on the formation of organogel, which was of great practical significance to improve the shelf life of peanut butter.

Formation, characterization, and potential food application of rice bran wax oleogels: Expeller-pressed corn germ oil versus refined corn oil.

The expeller-pressed (EP) corn germ oil oleogels were prepared using rice bran wax (RBX) at different concentrations (3, 5, 7, and 9 wt%). Their structural properties, including color, hardness, thermal behavior, rheological property, and crystal structure were evaluated. The performance of oleogels for potential food application was examined by incorporating oleogels into cookies as a fully replacement for commercial shortenings. Overall, RBX could form oleogels in both refined and EP corn germ oils at a concentration ≥3 wt%. Refined corn oil produced a stronger gel than crude corn oil. When comparing cookie characteristics, cookies made with both types of oleogels showed similar properties with commercial cookies. This result indicates that oleogels made by refined and EP corn germ oil together with RBX have the potential to imitate the functionality of commercial shortening in the baking industry.

Oil Gelation Ability of a Rice Bran Wax and Botanical High-Melting-Point Alcohol Mixture.

Due to its availability and relatively high melting point, rice bran wax can be used in foods and cosmetics as an oil solidifying agent. The addition of high-melting-point alcohols to the wax to optimize its performance was investigated. Such alcohols were prepared by the hydrolyzation of rice bran wax or carnauba wax. These alcohols had melting points of ～80°C, higher than that of rice bran wax, and consisted of hydrocarbons with alkyl chain lengths ranging from C24 to C34, much longer than the alkyl chains found in commercially available higher alcohols. Oil gel made with only rice bran wax as a solidifying agent has lower hardness than the conventional hydrocarbon wax gel, too low for practical usage in stick cosmetics such as lipsticks and lip creams. Blending high-melting-point alcohols with rice bran wax at 10-20% led to marked increase in gel hardness, equivalent to the gel hardness of the hydrocarbon wax. This effect on rice bran wax was not observed in commercially available higher alcohols and esters with lower melting points. Based upon the change in microstructure observed with SEM, the improved gel hardness of the rice bran wax upon addition of high-melting-point alcohols was probably induced by the disappearance of spherical clusters, originally presented in the gel, resulting in close to uniform morphology.

Oleogelation of emulsified oil delays in vitro intestinal lipid digestion.

Oleogelation is shown to delay the in vitro digestion of soybean oil (SBO) dispersed within an oil-in-water (O/W) emulsion. Rice bran wax (RBX) was used as an oleogelator at concentrations of 0, 0.25, 0.5, 1 and 4 wt% of the emulsions. All emulsions, which contained 1 wt% whey protein and 20 wt% oil and were prepared via hot homogenization, were kinetically stable against phase separation during the experimental timeframe (4 weeks), except at 4 wt% RBX where wax crystals 3-5 µm in length appeared within the dispersed oil phase, and which resulted in some emulsion instability. Rheological and thermal analysis of the emulsions and their corresponding SBO-RBX blends showed that the RBX led to formation of rigid oil droplets. Both in vitro gastric and intestinal digestion resulted in extensive oil droplet coalescence in all emulsions. Free fatty acid (FFA) release profiles showed that dispersed phase oleogelation delayed intestinal lipid digestion, with this effect enhanced up to 1 wt% RBX. A further increase to 4 wt% increased the rate of lipid digestion, which was ascribed to emulsion instability resulting from growth of intra-droplet RBX crystals.

Interesterification of rice bran wax and palm olein catalyzed by lipase: Crystallization behaviours and characterization.

Rice bran wax (RBW) is a traditional plant based natural wax and an increasingly popular component in textiles, fruit coatings and cosmetics. Properties of RBW can be modified by acyglycerols, and the resulting products can possess features with great potential in different applications. In this study, RBW was interesterified with palm olein (POL) catalyzed by Lipozyme TL IM, and the effects of RBW on the crystallization rate, solid fat content (SFC) and thermodynamic properties were investigated. The crystallization rates of RBW-based enzymatically interesterified (EIE) products were significantly higher than both the starting mixture and fully hydrogenated rapeseed oil (FHRSO). The EIE RBW-based samples were predominantly crystallized in ß' form, and presented a much smoother SFC profile as compared to physically blended raw materials. The SFC values were significantly decreased, conversely increased, and remained constant, and at 10 °C, 20-30 °C, and 35-40 °C as the wax ester and acylglycerols compositions changes. Overall, RBW-based samples after EIE showed an increased hardness and good surface properties, which make it a potential plastic fats substitute.

Structure and rheology of oleogels made from rice bran wax and rice bran oil.

Structural and rheological properties of oleogels consisting of 0.5-25 wt% rice bran wax (RBX) in rice bran oil (RBO) were explored. RBX was an efficient, thermoreversible oleogelator capable of structuring RBO at concentrations as low as 0.5 wt% RBX. A qualitative temperature-composition phase diagram showed that oleogels containing higher concentrations of RBX were expectedly the most resistant to melting. In oleogels at higher RBX concentrations, polarized light microscopy revealed the presence of a network of interlinked, long aspect ratio wax crystal needles up to 50 µm long. Upon heating, RBX crystals did not undergo any structural transition, based on the constant short spacings at ~ 4.16 and ~ 3.73 Å, indicative of an orthorhombic subcell, and d001 long spacing at 74-76 Šthat persisted until RBX fusion. This long spacing was ascribed to the presence of wax esters consisting of long-chain saturated fatty acids (C24 and C22) esterified to C28 - C34 saturated fatty alcohols. During cooling from 90 to 20 °C, the increase in oleogel viscosity resulting from the RBX liquid-solid phase transition was corroborated by DSC-based crystallization onset and enthalpy data. Similarly, elastic moduli and hardness both rose with increasing RBX concentration. This study, which demonstrated that RBX can structure RBO with distinct concentration-dependent properties, serves as the foundation for the development of oleogel-based approaches to saturated and trans fats replacement in processed foods.

Replacement of pork fat in frankfurter-type sausages by soybean oil oleogels structured with rice bran wax.

The objective of this study was to assess the impact of replacing pork backfat with rice bran wax oleogels on the organoleptic properties of frankfurter-type finely-comminuted sausages. Frankfurters were formulated using the following treatments as lipid replacement: 1) pork fat (PF); 2) soybean oil (SBO); 3) 2.5% rice bran wax oleogel (2.5 RBW); 4) 10% rice bran wax oleogel (10 RBW); and 5) 2.5% rice bran wax oleogel sheared less during frankfurter production (RBW/LS). In general, control PF was darker and redder than other treatments. TPA revealed oleogel treatments to be similar (P > .05) to pork fat treatment for firmness, chewiness, and springiness. Additionally, sensory evaluation revealed that replacing pork fat did not influence cured frankfurter aroma, but cured frankfurter flavor was significantly reduced (P < .05). Furthermore, lipid oxidation significantly (P < .05) differed between PF and 10 RBW. The results show that rice bran wax oleogels have the potential to successfully replace pork fat in comminuted products.

Rice Bran Oil: A Versatile Source for Edible and Industrial Applications.

Rice bran oil (RBO) is healthy gift generously given by nature to mankind. RBO is obtained from rice husk, a byproduct of rice milling industry and is gaining lot of importance as cooking oil due to presence of important micronutrient, gamma oryzanol. Its high smoke point is beneficial for its use for frying and deep frying of food stuff. It is popular because of balanced fatty acid profile (most ideal ratio of saturated, monounsaturated and polyunsaturated fatty acids), antioxidant capacity, and cholesterollowering abilities. Rice bran wax which is secondary by-product obtained as tank settling from RBO is used as a substitute for carnauba wax in cosmetics, confectionery, shoe creams etc. It can be also used as a source for fatty acid and fatty alcohol. The article is intended to highlight for the importance of RBO and its applications.

Characterization of rice bran wax policosanol and its nanoemulsion formulation.

Policosanol, a mixture of long-chain alcohols found in animal and plant waxes, has several biological effects; however, it has a bioavailability of less than 10%. Therefore, there is a need to improve its bioavailability, and one of the ways of doing this is by nanoemulsion formulation. Different droplet size distributions are usually achieved when emulsions are formed, which solely depends on the preparation method used. Mostly, emulsions are intended for better delivery with maintenance of the characteristics and properties of the leading components. In this study, policosanol was extracted from rice bran wax, its composition was determined by gas chromatography mass spectrophotometry, nanoemulsion was made, and the physical stability characteristics were determined. The results showed that policosanol nanoemulsion has a nanosize particle distribution below 100 nm (92.56-94.52 nm), with optimum charge distribution (-55.8 to -45.12 mV), pH (6.79-6.92) and refractive index (1.50); these were monitored and found to be stable for 8 weeks. The stability of policosanol nanoemulsion confers the potential to withstand long storage times.

The potential application of rice bran wax oleogel to replace solid fat and enhance unsaturated fat content in ice cream.

The development of structure in ice cream, characterized by its smooth texture and resistance to collapse during melting, depends, in part, on the presence of solid fat during the whipping and freezing steps. The objective of this study was to investigate the potential application of 10% rice bran wax (RBW) oleogel, comprised 90% high-oleic sunflower oil and 10% RBW, to replace solid fat in ice cream. A commercial blend of 80% saturated mono- and diglycerides and 20% polysorbate 80 was used as the emulsifier. Standard ice cream measurements, cryo-scanning electron microscopy (cryo-SEM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) were used to evaluate the formation of structure in ice cream. RBW oleogel produced higher levels of overrun when compared to a liquid oil ice cream sample, creating a lighter sample with good texture and appearance. However, those results were not associated with higher meltdown resistance. Microscopy revealed larger aggregation of RBW oleogel fat droplets at the air cell interface and distortion of the shape of air cells and fat droplets. Although the RBW oleogel did not develop sufficient structure in ice cream to maintain shape during meltdown when a mono- and diglycerides and polysorbate 80 blend was used as the emulsifier, micro- and ultrastructure investigations suggested that RBW oleogel did induce formation of a fat globule network in ice cream, suggesting that further optimization could lead to an alternative to saturated fat sources for ice cream applications.