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.