Fresh Satsuma mandarin juice was packed at 95_??_96°C in brown glass bottles with or without a tin plate. A capillary gas chromatograph with a flame photometric detector was used to monitor dimethyl sulfide (DMS) in the bottled juices during 16 weeks of storage at 0°C, 25°C, and 40°C. Considerable differences in DMS were observed between juices with and without the tin plate. It is probable that the tin plates inhibited DMS formation in the Satsuma mandarin juice.
To analyse the amounts of various cellular components in cultured mammalian cells by flow cytometry, we tried to reduce the autologous fluorescence in human-human hybridoma HB 4 C 5 cells producing IgM. The autologous fluorescence of the cells decreased after repeated rinsing with phenol red-free MEM medium at 4°C before and after ethanol-fixation. The method could be useful in the analyses of various cellular components by flow cytometry.
Strawberry fruit of the Toyonoka variety was picked at three stages of maturity: small green (I), pale green_??_white (II), and red ripe (III). Polygalacturonase (PG) activity was found at all stages of maturity. Although PG activity was very low, stage III fruit was estimated to have about six times the activity of stage I fruit. The crude enzyme from the red ripe fruit was partially purified by affinity chromatography on a crosslinked cell wall column prepared from citrus peels, and it was characterized as a mixture of exo- and endo-PG by high performance liquid chromatographic analysis of the degradation products of pectic acid. Both activities were found also in the red ripe fruits of two other varieties (Hokowase and Nyoho).