ISHS Acta Horticulturae 318: II International Symposium on Specialty and Exotic Vegetable Crops
HARVEST MATURITY AND STORAGE TEMPERATURE EFFECTS ON QUALITY OF CHINESE WATER CHESTNUTS (ELEOCHARIS DULCIS) |
| Authors: | J.K. Brecht, K.A. Bergsma, C.A. Sanchez, G.H. Snyder |
| Keywords: | Matai, respiration, texture, sugar, starch |
| Abstract:
Chinese water chestnuts were grown in Belle Glade, Fla. and stored and evaluated in Gainesville, Fla. At harvest, corms were separated into size classes of 1.6 (1987–88 only), 1.9, 2.5 and 3.2 cm diameter and stored for up to 2 months at 1, 5 or 10C. Initial soluble sugar levels were less than 1% FW in 1987–88 but averaged about 3% FW in 1988–89. Sugar levels increased by at least 2 fold at all temperatures during the first month of storage but did not increase further during the second month of storage and did not differ significantly among harvests. Increases in sugar levels during storage were greatest in the earliest-harvested corms, the larger (2.5 and 3.2 cm) sizes and at 10C storage temperature. Initial starch levels were generally greater than 20% FW and as high as 35% FW except in the first harvest of the 1988-planted water chestnuts, which appeared to be immature; initial starch levels in those corms were only 6–8% FW. Starch changes in storage mirrored sugar changes, decreasing especially in earlier-harvested corms, larger sizes and at 10C storage temperature. The smallest (1.9 cm) corms from the earliest 1988 harvest exhibited symptoms of chilling injury (internal browning and watersoaking, external decay) within 10 days at 1C; by 21 days they were shriveled and badly discolored. Incidence of decay (mainly due to Fusarium sp. and Geotrichum sp.) was otherwise greatest at 10C. Weight loss during storage was insignificant (less than 1% FW) in all cases except those corms showing chilling injury. Texture measurements using an Instron shear cell indicated that smaller and less mature corms were more tender than larger and mature corms, respectively, however texture changes during storage were small. Chinese water chestnut corms can be harvested based on epidermis (peel) development and mature corms stored at 1 or 5C with very little deterioration. With development of effective decay control, 10C storage may be desirable due to the greater sweetening that occurs at that temperature. | |
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