Technological and qualitative aspects of calabash gourd, Lagenaria siceraria (Molina) Standley, for processing

The calabash gourd or bottle gourd, Lagenaria siceraria (Molina) Standley, is a minor vegetable crop cultivated in South Italy for its immature fruits and young shoots used as food. A substantial increase in consumption could come from processing. This research provides preliminary information on suitability of preparation for frozen and 'ready to use' products. Slices of 1 cm thickness were blanched for 0, 30, 60, 90, 120, 150, 180 and 240 seconds in boiling water at 100 °C. Peroxidase and polyphenoloxidase activity were evaluated in relation to blanching period. Total enzymatic inactivation of blanched samples (residual peroxidase activity < 1%) was obtained in 180 seconds. Moreover, sugar and phenolic content of the fresh product were assayed, providing a partial nutritional characterisation of this vegetable. Glucose and fructose (about 1:1 ratio) and traces of sucrose were found; in addition, a small amount of unidentified mono- and di-caffeoylquinic acid derivatives was detected. Fresh 1 cm thick slices were dipped for 90 seconds in ascorbic or citric acid solution at 0.2-0.5 and 1% concentration and stored in sealed plastic bags at 4°C for 15 days. Organoleptic characteristics and colour parameters were evaluated on fresh and stored product. The best results were obtained dipping the slices in 0.2% citric acid solution.