Abstract
The authors studied the relationship between the carotenoid and chlorophyll contents in a squash (Cuculbita maxima) pulp and its color change in the process of maturation in a field. They also carried out the similar study foy the squash which was picked after maturation and stored at two levels of temperature, 10 and 25°C, for 3 months till the winter solstice. The results are as follows : 1) As the peel color changed from yellow-green to yellow during maturation, the chlorophyll in the pulp gradually decreased and finally disappeared at the full-mature stage. On the other hand, the carotenoids in the pulp decreased once but began to increase gradually after that and showed drastic increase at full-mature stage. 2) The carotenoid content in the pulp of the stored squash rapidlly increased and, after 3 months of storage, it became 2. 4 times (at 10°C storage) and 3. 7 times (at 25°C storage) as much as that in the squash at the time of full-mature in a field. The a value of the pulp indicated on the red-scale increased with the storage time and the correlation coefficients between a value and carotenoid content were 0. 883 at 10°C storage and 0. 922 at 25°C storage, respectively. 3) The total carotenoid content was 6. 2 mg/100 g in the fully matured squash with the itemization of 63. 9 % of lutein, 10. 9 % of α-carotene, 7. 8 % of β-carotene, 6. 0 % of antheraxanthin, 4. 3 % of violaxanthin, 2. 6 % of α-cryptoxanthin, 1. 6 % of auroxanthin, 1. 6 % of ζ-carotene and 1. 2 % of neochrome. 4) In the process of maturation, lutein, β-carotene and violaxanthin increased similarly to total carotenoid content. Lutein showed a considerable increase and other carotenoids such as β-carotene, antheraxanthin, α-cryptoxanthin and neochrome showed some increase after 3 months of storage, and it was distinctive that α-carotene disappeared after 2 months storage. 5) Vitamin A activity diminished temporalily during maturation and then turned to increase, reaching to 450 IU/100 g at fully matured stage. In case of the stored squash for 3 months, the vitamin A activity became 4. 3 times at 10°C and 4. 8 times at 25°C as much as that in the squash fully matured in a field. These data suggested that the synthesis of carotenoids was in process during storage, which resulted in the increase fo vitamin A activity.
