Ascorbic acid, aroma compounds and browning of orange juices related to PET packaging materials and pH

• Published in: Journal of the science of food and agriculture 2006-10, Vol.86 (13), p.2206-2212
• Main Authors: Berlinet, C, Brat, P, Brillouet, J.M, Ducruet, V
• Format: Article
• Language: English
• Subjects: aroma compounds; ascorbic acid; Biological and medical sciences; Botany; browning; Chemical Sciences; Citrus; Containers; enzymatic browning; Food engineering; Food industries; food packaging; food storage; Fruit and vegetable industries; Fruit juices; Fundamental and applied biological sciences. Psychology; General aspects; Handling, storage, packaging, transport; Life Sciences; odor compounds; off flavors; orange juice; packaging materials; polyethylene terephthalate; Polymers; storage quality; Vitamin C
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.2597

The ascorbic acid content of orange juice made from concentrate was measured after 9 months of storage at 20 °C in glass, standard monolayer polyethylene terephthalate (PET₁), multilayer PET (PET₂) and plasma-treated PET (PET₃) containers. Glass enabled the best preservation of ascorbic acid and, in plastic packaging materials, ascorbic acid losses were correlated with their oxygen permeability. PET₂ and PET₃, which exhibit oxygen permeability 10 times less than that of PET₁, enabled a gain of 100 mg L⁻¹ after 9 months of storage. Freshly hand-squeezed orange juice samples were adjusted to various pH values using sodium hydroxide; a rise in the pH from 3.2 to 4.0 significantly reduced the amounts of off-flavours (i.e., furfural and α-terpineol) appearing during storage, by 79% and 65%, respectively. Moreover, an increase in the pH from 3.2 to 4.0 enabled the protection of ascorbic acid levels without detrimentally increasing non-enzymatic browning.