Kinetic models of non-enzymatic browning in apple puree

✍ Scribed by A Ibarz; J Pagán; S Garza

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 157 KB
• Volume: 80
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/1097-0010(200006)80:8<1162::aid-jsfa613>3.0.co;2-z

✦ Synopsis

The effects of thermal treatments on 11 °Brix apple puree were studied at temperatures from 80 to 98 °C. Colour changes (measured by re¯ectance spectroscopy, colour difference, L*, a* and b* and the evolution of 5-hydroxymethylfurfural (HMF) and sugars (hexoses and sucrose) were used to evaluate non-enzymatic browning. A kinetic model based on a two-stage mechanism was applied to the evolution of colour difference and a*. A ®rst-order kinetic model was applied to L* evolution, while the evolution of absorbance at 420 nm (A 420 ) of the liquid fraction was described using a zero-order kinetic model. Thermally treated samples became more reddish and suffered a slight loss of yellow hues. The effect of temperature on the kinetic constants was described by an Arrhenius-type equation. The presence of pulp in the samples led to activation energies for A 420 and sucrose which were lower than those found previously for clari®ed juices with the same soluble solids content.