Effect of Hot Water Treatment with Organic Additives in Fresh Cut Carrot

Abstract

Fresh cut carrot (Daucus carota L.) slices were treated with hot (60°C) water and hot aqueous solution (2% sodium chloride, 2% citric acid and 10% lime juice) for 1 min and then surface water was removed. Following treatment, fresh-cut carrot slices were kept in a polypropylene (PP) box and stored in a refrigerator (4±1°C and 50±5% RH) for 12 days. The effectiveness of the treatments in extending shelf life was evaluated by determining respiration rate, firmness, weight loss, external colour, whiteness index (WI), some chemical parameters (ascorbic acid content, TSS, acidity, pH, total sugar, reducing sugar and beta carotene), total bacterial count (TBC) and sensory quality. The highest increment of WI (48.4%) was observed without heat-treated carrot slices. On the other hand, WI was increased by 12.1% and 21.7% in carrot slices treated with hot aqueous solution of 2% citric acid and with hot aqueous solution of 2% sodium chloride respectively at 12 days of storage. On the 12th day of storage, fresh-cut carrot treated with hot aqueous solution of 2% citric acid scored 7.3 and the rest of the sample scored less than 4.5 (indicate as unacceptable) in overall acceptability. Carrot slices treated with hot aqueous solution of 2% citric acid and 2% sodium chloride retained a minimum number of TBC and delayed changes in WI, external colour and beta carotene content compared to without heat-treated carrot slices. Keywords: Citric acid, respiration rate, sensory quality, sodium chloride, total bacterial count, whiteness index