The Influence of pH and Sodium Hydroxide Exposure Time on Glucosamine and Acrylamide Levels in California-Style Black Ripe Olives

• Autores: Suthawan Charoenprasert, Jerry A. Zweigenbaum, Gong Zhang, Alyson E. Mitchell
• Localización: Journal of food science, ISSN 0022-1147, Vol. 82, Nº 7, 2017, págs. 1574-1581
• Idioma: inglés
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• Resumen

  • Acrylic acid, N-acetyl-glucosamine and glucosamine were investigated for their role in the formation of acrylamide in California-style black ripe olives [CBROs]. Levels of acrylic acid and glucosamine are reported for the first time in fresh (333.50 ± 21.88 and 243.59 ± 10.06 nmol/g, respectively) and in brine-stored olives (184.50 ± 6.02 and 165.88 ± 11.51 nmol/g, respectively). Acrylamide levels significantly increased when acrylic acid (35.2%), N-acetyl-glucosamine (29.9%), and glucosamine (124.0%) were added to olives prior to sterilization. However, isotope studies indicate these compounds do not contribute carbon and/or nitrogen atoms to acrylamide. The base-catalyzed degradation of glucosamine is demonstrated in olive pulp and a strong correlation (r2= 0.9513) between glucosamine in olives before sterilization and acrylamide formed in processed CBROs is observed. Treatment with sodium hydroxide (pH > 12) significantly reduces acrylamide levels over 1 to 5 d without impacting olive fruit texture. Commercial California-style black ripe olive processing methods result in relatively high levels of acrylamide in the finished product. The mechanism for acrylamide formation in processed olives is not understood and remains elusive. Herein, we describe a method for measuring N-acetyl-glucosamine and glucosamine in olives and demonstrate that there is a relationship between glucosamine levels in raw olive fruit and acrylamide levels in processed olives. Additionally, we demonstrate that glucosamine undergoes base-catalyzed hydrolysis and that treatment of olives with sodium hydroxide (pH > 12) significantly reduces acrylamide levels over 1 to 5 d without impacting olive fruit texture.