The Effect of Packaging and Pre-Packaging Treatments on Quality of Fresh-Cut Spinach During Cold Storage

Abstract

Fresh cut spinach leaves (Spinacia oleracea L.) can be used for preparing many types of delicious dishes or eaten raw along with green salads because of its high nutritional value. Different pre-packaging dipping treatments and local packaging materials were used to extend the shelf life of this highly perishable product. The dipping solutions for shredded spinach leaves (2 cm in width) were: water (control), ascorbic acid (0.2%) and potassium permanganate (0.02%). After dipping, drained samples were then packaged in two polypropylene (PP) pouches (12 × 20 cm) of different thickness (22, and 30 ) and in polystyrene (PS) trays over-wrapped with a clear stretch polyvinylidene chloride (PVdC) film. Packaged samples were kept refrigerated at 4±0.5 C and 85±3 % R.H. for nine days. Water loss of packaged shredded spinach leaves, was minimal for samples packaged in PP-22µ and PP-30µ pouches, whereas those packaged in PS trays showed higher weight loss. The water treated samples showed the least shelf life. Other treated samples showed lower microbial counts initially and continued lower during storage. Samples treated with ascorbic acid were the best followed by those treated with potassium permanganate. Deterioration in color (yellowing) was fast notable for the water dipped samples, whereas ascorbic acid treated samples had higher panelists' scores for color during storage. Fresh cut spinach leaves packaged in PS trays showed about 9 days shelf life, compared with 6 days for those packaged in PP pouches. It is recommended to package ascorbic acid treated fresh cut spinach leaves in PS-tray covered with stretch PVdC overwrap than using PP pouches which, unless perforated, may lead to development of in-package anaerobic atmosphere.