Effect of processing on quality and shelf life of leafy vegetables

There is a need to sustain quality of ready-to-eat (RTE) leafy vegetables in order to improve shelf life of the products during postharvest storage. The main objective of this thesis was to investigate the effect of compression towards the quality and shelf life of the RTE leafy vegetables. This thesis focused on spinach leaves as the representation of the RTE leafy vegetables. For this purpose, uniaxial compression was chosen as a method to induce damage to the leaves. The effects of compression towards qualities of RTE spinach were evaluated. The quality measures in this study focused on mechanical and microstructural properties, physical appearance, and fresh weight. Organic spinach was found to be the best type in resisting stress compared to Teen, Salad, and Baby spinach. Population test was developed to categorise the compressed leaves into degrees of leaf injuries known as Undamaged, Minor, Halfway, and Complete teared. Force 200N was suggested to be the minimum required to pick up differences of the leaves deteriorations before and after storage. Uncompressed spinach leaves were found to have a shelf life of 14 days. Higher degrees of leaf injuries which are Halfway and Complete teared showed obvious decay since before storage. Sensory test was also conducted to study consumers’ evaluations towards visibility of leaf damage and perceptions in buying the product. Respiration rate of the RTE spinach stored at different films was also measured using a closed system. Michaelis-Menten and exponential models were used to study the respiration rate mechanism