低场核磁共振技术对不同贮藏条件下雷竹笋水分迁移规律的研究

摘要

In this paper, we investigated the moisture migration and hardness of bamboo shoots by using the low-field nuclear magnetic resonance technology(LF-NMR) at different storage temperatures(25℃, 4℃, -3℃, -18℃). By comparing of the peak area of bound water A21, immobilized water A22and free water A23, the result showed that the free water in bamboo shoot was the first to be drained at a fast rate.Further, the rate of dehydration of bamboo shoots was the fastest at 25℃. In the early storage stage, the water content of bamboo shoots under the four storage conditions didn't change obviously. After 7 days, the changes of the immobilized water at 25℃ and 4℃ were significant. After 14 days, the partial frozen (-3℃) and frozen (-18℃) methods could significantly delay the loss rate of free water and keep the liquidity of water. By the pseudo-color map analysis and hardness mea-surement of texture analyzer, we found that there were smaller ice crystals under the partial frozen (-3℃) condi-tion than the other three conditions, and less affect the organic structure and the uniform distribution of water.%本研究以雷竹笋为材料,利用低场核磁共振技术对在不同贮藏温度(常温25℃、冷藏4℃、微冻-3℃、冻藏-18℃)下雷竹笋水分的迁移规律及其硬度进行研究.结果表明:通过比较结合水A21、不易流动水A22、自由水A23的峰面积发现,自由水最先流失且明显快于结合水和不易流动水,在25℃下雷竹笋失水速率最快;在贮藏初期,四种储藏方式下的竹笋结合水含量没有明显变化;7d后,常温和冷藏方式的不易流动水变化明显;14d后,微冻和冷冻方式能明显延缓自由水的损失,保持水的流动性;通过伪彩图分析及质构仪对四种方式的硬度测量,微冻(-3℃)条件相对于其它三种方式能生成更小的冰晶,且对组织结构及水的均匀分布性影响较小.