冷冻预处理对黑蒜水分迁移和质构的影响

用大蒜作为研究材料，应用冷冻技术进行预处理加工黑蒜，用低场核磁、色差仪、TPA和DNS法等方法测定大蒜样品的水分分布、褐变度、质构特性以及还原糖含量变化。低场核磁测定结果显示，冷冻预处理使大蒜T₂₂质子密度上升，自由水相对含量升高，水分迁移速度变快；色差仪测定结果显示，冷冻预处理促进了美拉德反应的进行；TPA测定结果显示，冷冻使黑蒜的硬度显著降低；还原糖含量测定结果显示，冷冻加速了还原糖的生成，促进了美拉德反应。

Effects of freezing pretreatment on water migration and texture of black garlic

Garlic was processed with freezing pretreatment, and the water migration, browning degree, texture and reducing sugar content of garlic samples were determined by low field NMR, colorimeter, TPA, DNS methods, respectively. The results of low field NMR showed that freezing pretreatment increased the proton density of garlic T₂₂, in addition to increasing the relative content of free water and the speed of water migration; the colorimeter results demonstrated that freezing pretreatment promoted the Maillard reaction; TPA results indicated that the hardness of black garlic was significantly decreased by freezing; the determination of reducing sugar content reflected that the freezing treatment accelerated the turnout of reducing sugar so as to accelerate the Maillard reaction.