Cutting shape, film and storage temperature affect the shelf-life of fresh-cut pumpkin

Pumpkins (Cucurbita spp. L.) can be used in large scale in the fresh-cut sector, due to their increasing consumption in many countries. The processing operations of pumpkins include peeling, portioning and packaging. A research has been conducted in order to study how the cutting shape (sliced or 2-cm diced), packaging permeance to O2 (P1=1990; P2=750; P3=560 cm3 m-2 d-1 bar-1) and storage temperature (4 or 8°C) can affect the physiology and quality of fresh-cut 'Cinderella' pumpkin (Cucurbita maxima Duchesne) stored for an 8-day shelf-life period (d8). The gas composition (O2; CO2), pigments, total phenolic content (TPC), antioxidant power (AP) and Vitamin C (Vit. C) content were analyzed at processing and during the shelf-life period (d5 and d8). Fresh weight loss was recorded daily. During the shelf-life, the O2 and CO2 contents were found to only depend on the cutting shape and temperature. The O2 in the headspace decreased more significantly at 8°C than at 4°C, and more in the bags containing pumpkin dices than in the bags containing pumpkin slices. However, the O2 levels on d8 were similar and not statistically different in both bags containing dices and slices and in the bags stored either at 4 or at 8°C, respectively. The CO2 in the headspace increased more in the bags stored at 8°C than in the bags stored at 4°C, and more in the bags containing pumpkin dices than in the bags containing pumpkin slices. Fresh weight was affected by the film during the shelf-life, regardless of the storage temperature, with an increasing weight loss as the O2 permeance of the films decreased; P3 showed a more significant weight loss than the higher permeance films. A significant interaction between film and shape was observed from d6 to d8: The weight loss of the pumpkin slices continued to increase as the permeance decreased, whereas it decreased as the permeance increased. The Chlorophyll b, Vitamin C and carotenoid contents were affected by the film × shape interaction on d5. All the variables of the pumpkin dices decreased as the O2 permeance increased, while they increased in the pumpkin slices packaged with the intermediate O2 permeance film. AP was affected by shape × O2 permenace on d8. Chlorophyll was not affected by the treatments. TPC and AP were only affected by temperature × shape on d8, while the Vitamin C and carotenoid values were affected by the temperature, with higher values at 4°C of storage than at 8°C.