Effects of thermal and high-pressure treatments on the carotene content, microbiological safety and sensory properties of acidified and of non-acidified carrot juice

- 100% natural carrot juice without preservatives was used for the study.
- Carrot juice was processed by high pressure (HPP) and mild heat (MH).
- No significant improvement in shelf life was observed by the acidification with GDL.
- An equivalent microbiological reduction was obtained for both HPP and MH treatments.
- HPP carrot juice showed better sensory properties than the MH one.

This study aims to assess the changes that are induced by thermal and non-thermal treatments on acidified and non-acidified carrot juice. Glucono-delta lactone (GDL) was used to reduce the pH of juice to 5.5. Carrot juice was treated using high pressure (HP) and mild heating (MH). The microbiological safety, physicochemical parameters, α and β-carotene content and sensory characterisation were evaluated for 29 days of storage at 5 ± 2 °C. Both treatments resulted in an equivalent reduction of microbial growth, and compared with the unprocessed samples, both HPP and MH processes induced modifications in the carotene content, colour, acidity and °Brix. These changes remained stable during storage. HPP processing provides carrot juice with better sensory properties than MH. Acidification by adding GDL did not significantly extend the shelf-life but had a detrimental effect on the sensory attributes.