Factors that impact the stability of vitamin C at intermediate temperatures in a food matrix

- Extrinsic factors were crucial for vitamin C stability in the apple purée serum.
- The temperature impact in the range 60-80 °C was not significant though.
- Intrinsic factors did not or only slightly influence degradation of vitamin C.
- Adequate geometry of recipients might help to stabilize vitamin C.

The study comprises a systematic and quantitative evaluation of potential intrinsic and extrinsic factors that impact vitamin C degradation in a real food matrix. The supernatant of centrifuged apple purée was fortified in vitamin C, and degradation was followed without stirring. Model discrimination indicated better fit for the zero order model than the first order model which was hence chosen for determination of rate constants. pH influenced strongly vitamin C degradation in citrate-phosphate buffer but not in the apple purée serum. To get an idea of the impact of the food matrix, stability in apple purée serum was compared with that in carrot purée. In the latter, stability was slightly higher. Vitamin C degradation rates were not influenced by its initial concentration. The temperature effect was only marked in the temperature range 40-60 °C. In the range 60-80 °C, filling height of tubes had the greatest impact.