Acidity of oryzanol and its contribution to free fatty acids value in vegetable oils

Krishna, A. G. Gopala; Hemakumar, K. H.; Khatoon, Sakina

doi:10.1007/s11746-006-5154-3

Cited by 10 publications

(6 citation statements)

References 2 publications

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“…Receptor-mediated transduction may predominate at low stimulus concentrations, but when receptor binding is saturated and FFAs are available, diffusion may be the predominant route of passage across membranes (Ibrahimi and Abumrad 2002). Unbound FFA concentrations in the circulation may be in the nanomolar range (Azzazy et al 2006), but concentrations 6-8 orders of magnitude higher may occur in the oral cavity while eating (Rukunudin et al 1998;Wan et al 1998;Bertran et al 1999;Che Man et al 1999;Gopala Krishna et al 2006;Li et al 2008).…”

Section: Discussionmentioning

confidence: 99%

Oral Thresholds and Suprathreshold Intensity Ratings for Free Fatty Acids on 3 Tongue Sites in Humans: Implications for Transduction Mechanisms

Mattes

2009

Chemical Senses

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Multiple putative free fatty acid (FFA) transduction mechanisms have been identified in the oral cavity. They reportedly differ in their distribution on the tongue and each has a unique range of ligand specificities. This suggests that there should be regional differences in sensory responses to varying FFAs. This was assessed through spatial testing with caproic (C), lauric (L), and stearic (S) FFAs among 35 healthy adults. Stimuli were applied to the fungiform (FU), foliate (FO), and circumvallate (CV) papillae with a cotton-tipped applicator. Oral detection thresholds were measured by an ascending, 3-alternative, forcedchoice, sip and spit procedure. Intensity ratings were obtained on the general labeled magnitude scale. Nongustatory cues were minimized by testing with the nares blocked, eyes covered, and by masking tactile cues with the addition of gum acacia and mineral oil to the stimuli vehicle. Thresholds were obtained from nearly all individuals at each site, and the concentration was similar across the 3 FFAs. Absolute intensity ratings differed significantly with C > L > S overall and at the CV and FO papillae. At the FU papillae, the L and S ratings were comparable. Ratings were highest at the FU followed by the CV and then the FO papillae. Slopes of the concentration-intensity rating functions were higher for L compared with C and S at the CV papillae as well as both L and C compared with S at the FO papillae. However, overall, slopes were comparable across sites. These findings strengthen evidence for oral FFA perception in humans by replicating threshold sensitivity findings and documenting monotonic scaling ability for these stimuli. Further, they challenge current views on transduction as sensory responsiveness was observed at tongue sites not predicted to support FFA detection.

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Section: Discussionmentioning

confidence: 99%

Oral Thresholds and Suprathreshold Intensity Ratings for Free Fatty Acids on 3 Tongue Sites in Humans: Implications for Transduction Mechanisms

Mattes

2009

Chemical Senses

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“…However, oryzanol also reacts with alkali and provides a higher FFA value due to both oleic acid and oryzanol. To differentiate between the two, the real FFA ascribed to only oleic acid was calculated according to Gopala Krishna et al (2006a) and expressed as percent oleic acid. The following formula was used to calculate the real FFA content.…”

Section: Free Fatty Acid Valuementioning

confidence: 99%

Oryzanol as natural antioxidant for improving sunflower oil stability

et al. 2014

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Sunflower oil is being made shelf stable by the incorporation of synthetic antioxidants such as tertiary butyl hydroquinone (TBHQ), while natural antioxidants like oryzanol and tocopherols can also be used. The aim of the current investigation was to evaluate the antioxidant effect of natural oryzanol (Oz) concentrate (15.5 % oryzanol) and purified Oz (80 % oryzanol) on oxidative and thermal stability of sunflower oil. Sunflower oil was incorporated with Oz concentrate to provide 0, 0.12, 0.25, 0.50, 0.84, 1.0, 1.60, 2.0, 2.5 and 3.20 % oryzanol in the oil, stored for 5 weeks at 37 °C and oxidative stability was evaluated. It was found that the oryzanol concentrate showed good antioxidant effect with increase in concentration of oryzanol. In another set of experiments, sunflower oil containing purified Oz at 1 % level individually and in combination with 0.1 % α- tocopherol (α-T) was heated at 120 °C for 24 h to evaluate thermal stability. Sunflower oil containing 1 % Oz (80 % purity) showed 98.40 % and sunflower oil containing 1 % Oz and 0.1 % α-T showed 108.75 % antioxidant effect compared to TBHQ taken as 100 %. The study indicated that sunflower oil containing 1 % Oz (80 % purity) and 0.1 % α-T combination provides a synergistic effect in inhibiting primary and secondary products and showed highest thermal stability. SFO containing 1 % Oz added as concentrate also showed good antioxidant effect during storage. Hence, instead of using synthetic antioxidants like TBHQ, we can add natural oryzanol (purified or as concentrate) to sunflower oil to increase its oxidative and thermal stability.

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“…Tocopherols were identified and quantified by comparing the chromatograms with the standards, and content was reported in mg/kg. FFAs were determined by titration according to the AOCS Official Method Ca 5a-40 [25], with alkali blue selected as an alternative indicator because of the presence of oryzanol in RBO [7,26]. The FFA contents was calculated and expressed as the percentage of oleic acid equivalent (%), while the acid values were calculated as 1.99 times FFAs and reported in terms of mg KOH/g.…”

Section: Methodsmentioning

confidence: 99%

Production of Rice Bran Oil with Light Color and High Oryzanol Content by Multi‐stage Molecular Distillation

Jin

Xie

Chen³

et al. 2015

J Americ Oil Chem Soc

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SRO-II and SRO-III had a clear yellow appearance and a non-triacylglycerol content <1.5 %. These semi-refined oils were mixed directly after MMD and further refined by mild deacidification and winterization to obtain fully refined oil, which met the requirements of commonly used standards. Notably, the final oil exhibited light color and retained nearly 80 % of the oryzanol of raw oil. The yield of final oil reached 80-85 % through the entire refining process.

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Acidity of oryzanol and its contribution to free fatty acids value in vegetable oils

Cited by 10 publications

References 2 publications

Oral Thresholds and Suprathreshold Intensity Ratings for Free Fatty Acids on 3 Tongue Sites in Humans: Implications for Transduction Mechanisms

Oral Thresholds and Suprathreshold Intensity Ratings for Free Fatty Acids on 3 Tongue Sites in Humans: Implications for Transduction Mechanisms

Oryzanol as natural antioxidant for improving sunflower oil stability

Production of Rice Bran Oil with Light Color and High Oryzanol Content by Multi‐stage Molecular Distillation

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