Effect of the Simultaneous Interaction among Ascorbic Acid, Iron and pH on the Oxidative Stability of Oil-in-Water Emulsions

Autor(es)

Branco, Gabriel F. ^[1] ; Rodrigues, Maria I. ^[2] ; Gioielli, Luiz A. ^[3] ; Castro, Inar A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Fac Pharmaceut Sci, Dept Food & Expt Nutr, BR-05508900 Sao Paulo - Brazil

^[2] Univ Estadual Campinas, Fac Food Engn, Dept Food Engn, BR-13081970 Sao Paulo - Brazil

^[3] Univ Sao Paulo, Fac Pharmaceut Sci, Dept Biochem Pharmaceut Technol, BR-05508900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Agricultural and Food Chemistry; v. 59, n. 22, p. 12183-12192, NOV 23 2011.
• Citações Web of Science: 5

Resumo

The objective of this study was to demonstrate how different factors can simultaneously influence the oxidative stability of an oil-in-water emulsion, and how these factors can be used to enlarge the variation range of oxidation markers, expressed as peroxide value (PV) and TBARS. Initially, a Plackett-Burman design was used to screen seven factors (temperature, pH, and iron, copper, ascorbyl palmitate, ascorbic acid, and sodium chloride concentrations). A temperature elevation of 30 to 60 degrees C reduced PV and TBARS, a pH change from 3.0 to 7.0 increased PV and reduced TBARS, and the presence of ascorbic acid (1 mmol/L) had no significant effect on PV but increased TBARS (p < 0.05). Thus, the temperature was fixed at 30 degrees C, and an emulsion was formulated with different combinations of ascorbic acid, iron, and pH according to a central composite rotatable design. Regression models were fitted to PV and TBARs responses and optimized to get the higher values of both markers of oxidation. The optimized emulsion contained 1.70 mmol/L All (ascorbic acid) and 0.885 mmol/L FeSO(4)center dot 7H(2)O (1.0 mmol/L Fe(2+)) at pH 5.51 and 30 degrees C. The range of variation observed for oxidation markers in the optimized emulsion model (PV, 0-4.27 mequiv/L; TBARS, 0-13.55 mmol/L) was larger than the variation observed in the nonoptimized model (PV, 0-1.05 mequiv/L; TBARS, 0-1.00 mmol/L). The antioxidant activity of six compounds (Trolox, alpha-tocopherol, caffeic acid, gallic acid, catechin, and TBHQ) was evaluated using the optimized emulsion conditions. After application of the Tukey HSD post hoc statistical test, the samples that were not different (p < 0.05) in the nonoptimized emulsions showed a significant difference in the optimized emulsions. Considering the importance of the interactions on oxidation studies, our model represents a significant improvement in a direct methodology that can be applied to evaluate natural compounds under different combination of factors. (AU)

• Processo FAPESP: 08/09296-1 - Aplicação de técnicas fatoriais de planejamento no desenvolvimento de um modelo para avaliação da oxidação em ácidos graxos e emulsões.
• Beneficiário: Inar Castro Erger
• Modalidade de apoio: Auxílio à Pesquisa - Regular