Quality of minimally processed carrots as affected by warm water washing and chlorination.

摘要

Different applications of cold and warm tap water (4 degrees C and 50 degrees C) with and without chlorination, respectively, in the washing of uncut peeled carrots (Daucus carota L.) were conducted, and their effects on sensory and microbiological properties during storage for 9 days at 4 degrees C were assessed. To minimise cross-contamination of almost sterile inner root parts with the highly contaminated outer cortex during processing the peeled carrots were washed prior to cutting. The washing treatments were carried out using a commercial processing line, thus facilitating the scale-up to industrial production. Populations of aerobic mesophilic bacteria, lactic acid bacteria and enterobacteria on these minimally processed carrots were determined, and the sensorial quality of shredded carrots was evaluated by a sensory panel throughout storage. Additionally, colour, texture, sugars, and trichloromethanes were analysed. Washing uncut carrots with cold chlorinated water (200 mg/l, 4 degrees C) and warm tap water (50 degrees C) ensured sugar retention and reduced aerobic mesophilic bacteria by 1.7 and 2.0 log10 colony forming units per gram (cfu/g), respectively, while washing with warm chlorinated water (200 mg/l) resulted in a 2.3 log10 cfu/g reduction. By-product formation due to chlorination was negligible. Sensorial properties of the latter samples were slightly affected. It was shown that both washing uncut knife-peeled carrots with cold chlorinated water (4 degrees C) and warm tap water (50 degrees C), respectively, provided good microbiological safety paired with improved sensorial properties. Moreover, fresh-like character of the products was retained, as indicated by the persisting respiration of the living tissues..