低温处理对湘莲采后生理变化的影响

以新鲜湘莲为原料，于（4±0.1）℃和（25±0.1）℃贮藏条件下，测定湘莲采后水分、蛋白质、可溶性固形物含量（soluble solids content，SSC）、净光合速率、莲壳色差及感官质量变化。结果表明，贮藏温度对鲜莲水分含量、蛋白质含量、L*、a*、b*值及感官质量均具有极显著影响（P＜0.01）；此外，（4±0.1）℃贮藏期间，SSC的最高点（成熟饱和点）在21 d，较（25±0.1）℃贮藏（6 d）明显推迟；净光合速率从3 d之后持续维持在较低水平，始终居于（25±0.1）℃贮藏之下。由此说明，低温贮藏条件下，鲜莲组织水分散失减慢，蛋白质含量变化减缓，呼吸速率受到显著抑制，从而，大大保留了其营养价值和食用品质，鲜莲货架期延长。

Effect of Low Temperature on Postharvest Physiology of Xiang Lotus Seeds

In order to understand the postharvest physiological changes of fresh Xiang lotus seeds, the moisture content,
protein content, soluble solids content (SSC), and net photosynthetic rate of fresh lotus seeds (from Xiangtan county, Hunan
province) and the color variation of fresh lotus shells were studied at storage temperatures of (4 ± 0.1) and (25 ± 0.1) ℃.
The results showed that storage temperature had extremely significant effects on the moisture content, protein content, L*,
a* and b* values, and sensory quality of fresh lotus seeds (P ＜ 0.01). The peak level (mature saturation point) of soluble
solids was significantly delayed to appear on the 21st d of posthavest storage at (4 ± 0.1) ℃, compared to be the 6th d when
stored at (25 ± 0.1) ℃. Since the 3rd d of postharvest storage, the net photosynthetic rate of fresh lotus seeds at (4 ± 0.1) ℃
remained at a level lower than at (25 ± 0.1) ℃. These results indicate that low temperature (4 ± 0.1) ℃ storage can slow
down the water loss and protein degradation in fresh lotus, thus significantly inhibiting the respiration rate. Therefore, low
temperature storage can maintain the nutritional value and eating quality at the maximum extent, and extend the shelf life of
fresh lotus seeds.