Changes in Glucose Level and Activities of Acid and Alkaline Phosphatases of Solanum incanum L. During Storage

Abstract

Solanum incanum L. is an eggplant that is usually cooked before consumption. This study was designed to determine
the glucose level, activities of non-specific acid and alkaline phosphatases in S. incanum stored under ambient condition (30oC) and
refrigeration (10oC) for 22 days. Glucose level was found to decrease significantly (P<0.01)(from 0.588 ± 0.006 to 0.389 ± 0.002 %
fresh weight) in S. incanum stored in ambient condition and(from 0.588 ± 0.006 to 0.413 ± 0.002 % fresh weight) under refrigeration.
However, the decrease in glucose level of S. incanum (33.8%) stored under ambient condition was higher (26.7%) compared to that
stored under refrigeration. Acid phosphatase activity also increased significantly (P<0.01) in S. incanum stored both under ambient
condition and refrigeration. The increase(from 0.0036 ± 0.0002 to 0.0293±0.0004 μmol/min/g fresh weight) was higher in S. incanum
stored under ambient condition compared to S. incanum stored under refrigerated condition (from 0.0036 ± 0.0002 to 0.0240 ± 0.0004
μmol/min/g fresh weight).
Alkaline phosphatase activity decreased (from 0.029±0.0006 to 0.008±0.0002 μmol/min/g fresh weight) significantly (P<0.01) in S.
incanum stored under ambient condition. Under refrigeration, there was a decline in alkaline phosphatase activity of S. incanum from
day 1 to day 4 and a subsequent increase from day 4 to day 22. Storage reduced the level of glucose in S. incanum, thereby making it a
suitable diet in weight reducing programmes and in the management of diabetes mellitus. Under refrigeration, the increase in the
activity of alkaline phosphatase could be attributed to enhanced alkaloid biosynthesis that occurs at low temperature.