Assessing the Changes in Quality of Imported Apples (Malus Pumila) along the Postharvest Import Chain

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APRIL 2018
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Changes in quality parameters were studied on two commercially imported apple cultivars in Ghana: ‘Golden Delicious’ and ‘Pink Lady’, with the aim of investigating the changes in the apples along the postharvest import chain. Freshly imported apples were sampled and analysed for the following: percentage moisture, weight (and subsequent weight loss), total soluble solids, titratable acidity and pH using standard methods; and antioxidant activity using the DPPH assay. These results were used as control for changes that were recorded along the study. The rest of the samples were stored for a 90-day period under different conditions: Cold Room Storage (0 - 4 oC), Cold Shelf Storage (10 – 18 oC) and in Ambient Storage (25 – 28 oC), each representing a major stage in the postharvest import chain in Ghana. Sampling and analysis were done every 15th day for 90 days. Physical defects were also observed on sampling days. At the end of the 90 day storage period, storage of apples under cold room conditions retained better quality characteristics than all other storage conditions. Golden Delicious apples retained higher moisture content than the Pink Lady apples as storage progressed; even though a significant loss in weight was record on day 15 in both cultivars and in all storage conditions. Fresh samples of Pink Lady apples had 79% DPPH inhibition, as compared with 74% in Golden Delicious. However, a significant drop in the AA of Pink Lady apples occurred by day 30 in storage, whereas this was seen on day 60 for Golden Delicious apples, both in cold room storage. All samples under ambient storage had lost a significant amount of AA by day 15 in storage. Soft rot, Bitter pit and discolouration were also severe in the ambient storage samples. Changes in pH, total soluble solids and titratable acidity still fell within consumer acceptable ranges
A thesis submitted to the Department of Food Science and Technology, College of Science, in partial fulfilment of the requirements for the degree of Master of Science in Food Quality Management,