Abstract:Although the stability of rice bran oil (RBo) has been showed on several studies, the factors which make it capable on maintaining its stability under thermal oxidation has not been sure yet. We hypothesized that its fatty acid composition [high composition of oleic acid (oA), lower composition of linoleic acid (LA) and α-linolenic acid (LnA)] and/or its antioxidant agents [γ-oryzanol (OZ)] and vitamin E [tocopherol (Toc), tocotrienol (T3)] might be the biggest factor. To prove the hypothesis, we thermally oxi… Show more
“…The superior stability of rice bran oil observed from Figure 2 can be explained, similarly to the other oils, by a combination of fatty acid composition (high levels of oleic acid, lower levels of linoleic acid, and α-linolenic acid, see Table 2 ) together with high total antioxidant capacity ( Table 1 ). These conclusions agree well with previous storage stability studies, based on peroxide values, and show that the most stable oils were rice > soybean > sunflower oils [ 34 ].…”
This work aims to apply isothermal calorimetry for the determination of the oxidative stability of bulk oils by deriving kinetic and thermodynamic parameters. The method consists of measuring the heat flow produced during the oxidation of the oils in the presence of oxygen. To this purpose, an oil was recovered from olive seeds, the solid waste derived from the transformation of olives, by using two different technologies: supercritical carbon dioxide and mechanical press. The oxidative stability of both extracted oils was then compared with commercial sunflower, soybean, corn, and rice oils. The kinetic and thermodynamic parameters, obtained from the analysis of isothermal calorimetry traces at 60 °C, allowed the calculation of the oxidizability index obtaining the following ranking: olive seeds by supercritical carbon dioxide (3.55 ± 0.4 × 10−3 (s/M)0.5) > sunflower (3.42 ± 0.8 × 10−3 (s/M)0.5) > olive seeds by mechanical press (3.07 ± 0.3 × 10−3 (s/M)0.5) > soybean (2.44 ± 0.6 × 10−3 (s/M)0.5) > corn (1.11 ± 0.4 × 10−3 (s/M)0.5) > rice oils (0.98 ± 0.4 × 10−3 (s/M)0.5). The results were then supported with the analysis of total phenolic content, antioxidant activity, fatty acid profile, and peroxide values. Overall, the findings of the present study support the use of isothermal calorimetry as a direct and non-invasive technique for determining the oxidizability of bulk oils.
“…The superior stability of rice bran oil observed from Figure 2 can be explained, similarly to the other oils, by a combination of fatty acid composition (high levels of oleic acid, lower levels of linoleic acid, and α-linolenic acid, see Table 2 ) together with high total antioxidant capacity ( Table 1 ). These conclusions agree well with previous storage stability studies, based on peroxide values, and show that the most stable oils were rice > soybean > sunflower oils [ 34 ].…”
This work aims to apply isothermal calorimetry for the determination of the oxidative stability of bulk oils by deriving kinetic and thermodynamic parameters. The method consists of measuring the heat flow produced during the oxidation of the oils in the presence of oxygen. To this purpose, an oil was recovered from olive seeds, the solid waste derived from the transformation of olives, by using two different technologies: supercritical carbon dioxide and mechanical press. The oxidative stability of both extracted oils was then compared with commercial sunflower, soybean, corn, and rice oils. The kinetic and thermodynamic parameters, obtained from the analysis of isothermal calorimetry traces at 60 °C, allowed the calculation of the oxidizability index obtaining the following ranking: olive seeds by supercritical carbon dioxide (3.55 ± 0.4 × 10−3 (s/M)0.5) > sunflower (3.42 ± 0.8 × 10−3 (s/M)0.5) > olive seeds by mechanical press (3.07 ± 0.3 × 10−3 (s/M)0.5) > soybean (2.44 ± 0.6 × 10−3 (s/M)0.5) > corn (1.11 ± 0.4 × 10−3 (s/M)0.5) > rice oils (0.98 ± 0.4 × 10−3 (s/M)0.5). The results were then supported with the analysis of total phenolic content, antioxidant activity, fatty acid profile, and peroxide values. Overall, the findings of the present study support the use of isothermal calorimetry as a direct and non-invasive technique for determining the oxidizability of bulk oils.
“…As previously mentioned, we recently developed a novel and highly sensitive HPLC-MS/MS-based method that enables the detection of TGOOH at the fmol level [ 4 ]. On top of that, this method also allows for the selective detection of different molecular species of TGOOH, including isomers with minor structural differences near the OOH group ( e.g., OOH positional isomers) that leads to assess the oxidative stress ( i.e., radical or 1 O 2 oxidation) [ 4 , 11 ]. Hence, we considered that this method may be a useful tool for obtaining more conclusive data regarding the absorption of dietary TGOOH.…”
Section: Resultsmentioning
confidence: 99%
“…On top of that, our HPLC-MS/MS-based method is not only highly sensitive but also allows us to assess the oxidative stress ( i.e., radical or 1 O 2 oxidation) involved in TGOOH formation by discriminating the isomeric structure of TGOOH ( Fig. 2 ) [ 4 , 11 ], such feature is considered to be useful in examining the validity of hypothesis I and/or II. Fig.…”
“…FOH 28:0 is the main component of policosanol, a mixture of long chain fatty alcohols that can be found in the waxes of sugarcane [ 45 ], rice bran [ 46 ], wheat and flax straw [ 47 ], and other plant materials. Studies conducted on rice bran oil stored for 17 days at 40 °C, have found that only triglycerides were affected by oxidation due to the intramolecular formation of hydroperoxides, mainly in molecular species containing linoleic acid [ 48 ]. When FOH 28:0 and phytosterols were isolated from sugarcane rind and heated up to 300 °C, 21 degradation compounds from both FOH 28:0 and phytosterols were found, which were not identified [ 49 ].…”
Section: Resultsmentioning
confidence: 99%
“…However, in the case of the triglycerides, those changes only started after T1. It must be noted that as a result of oxidation, the fatty acid backbone of triglycerides can transform into hydroperoxides [ 48 ] and, afterwards, yield oxidized monomers, dimers, and oligomers in concentrations inversely correlated to those of free fatty acids [ 56 ].…”
The unstoppable growth of human population that occurs in parallel with all manufacturing activities leads to a relentless increase in the demand for resources, cultivation land, and energy. In response, currently, there is significant interest in developing strategies to optimize any available resources and their biowaste. While solutions initially focused on recovering biomolecules with applications in food, energy, or materials, the feasibility of synthetic biology in this field has been demonstrated in recent years. For instance, it is possible to genetically modify Saccharomyces cerevisiae to produce terpenes for commercial applications (i.e., against malaria or as biodiesel). But the production process, similar to any industrial activity, generates biowastes containing promising biomolecules (from fermentation) that if recovered may have applications in different areas. To test this hypothesis, in the present study, the lipid composition of by-products from the industrial production of β-farnesene by genetically modified Saccharomyces cerevisiae are studied to identify potentially bioactive compounds, their recovery, and finally, their stability and in vitro bioactivity. The assayed biowaste showed the presence of triterpenes, phytosterols, and 1-octacosanol which were recovered through molecular distillation into a single fraction. During the assayed stability test, compositional modifications were observed, mainly for the phytosterols and 1-octacosanol, probably due to oxidative reactions. However, such changes did not affect the in vitro bioactivity in macrophages, where it was found that the obtained fraction decreased the production of TNF-α and IL-6 in lipopolysaccharide (LPS)-induced inflammation.
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