EFFECT OF ASHED EGG-SHELL AND ASHED OYSTE R SHELL ON HARDNESS, CHEMICAL-COMPONENTS AND TISSUE STRUCTURE OF BRINED UME FRUIT

To make clear the effect of ashed objects on the hardness, chemical co mponents and tissue structure of brined ume fruit, small type ume frui t (Prunus mume Sieb. et Zucc.) were brined by NaCl solution containing egg shell dried at 105-degrees-C (DES), egg shell ashed at 500-degree s-C (AES-500) or 720-degrees-C (AES-720) or oyster shell ashed at 1000 -degrees-C (AOS). After brining of the fruit, a controlled amount of N aCl was added to each group once a day until NaCl concentration in the fruit reached to 18%. Two weeks after the final addition of NaCl, the hardness, Ca and pectin contents in each group were measured. Tissues prepared from fresh ume fruit and the brined ume fruit were also obse rved with a scanning electron microscope. Further, X-ray diffraction p atterns of DES, AES-500, AES-720 and AOS were analyzed with a X-ray an alyzer. The results obtained were as follows: (1) The ume fruit brined with DES, AES-500, AES-720 or AOS contained larger amounts of Ca than the fruit brined only by NaCl. (2) The fruit brined with DES or AES-5 00 shrank and the hardness value was smaller. Conversely, fruit brined with AES-20 or AOS didn't shrink and the hardness value was larger. ( 3) The fruit brined only by NaCl was remarkably smaller in the amount of Hot 0.05 N HCl soluble pectin (HSP) than the fresh ume fruit, and t he amount of Water soluble pectin (WSP) was significantly larger. (4) The brined fruit to which DES or AES or AES-500 was added, were remark ably smaller in HSP than the fresh ume fruit, and the amounts of WSP a nd Hexametaphosphate soluble pectin (HXSP) were significantly larger. (5) The fruit brined with AES 720 or AOS was remarkably smaller in the amount of HSP than the ume fruit, and larger in the amounts of HXSP a nd Cold 0.05 N NaOH soluble pectin. WSP remained mostly unchanged. (6) The X -ray diffraction patterns of both AOS and AES 720 were roughly similar to that of CaO, but those of DES and AES 500 were similar to t hat of CaCO3. (7) In observation with a scanning electron microscope, the cells of fruit brined with DES tended to flatten, but the those br ined with AOS were similar to that of fresh fruit. As a result, it is concluded that the hardness of the brined ume fruit with the egg shell ashed at 720-degrees-C or the oyster shell ashed at 1 000-degrees-C i s kept with a maintenance of the tissue structure caused by an obstruc tion of change of HSP into WSP which is formed through cross-linkage b etween pectin and Ca ion from CaO.