扁桃种仁氨基酸组分及加工品质分析

氧化程度对巴旦木营养和品质具有重要的影响，本研究的目的是建立一种灵敏、可靠的巴旦木氧化程度快速检测方法。本研究首先通过表面配体交换的转相策略实现了水溶液中分散的金纳米粒子（AuNPs）快速、简便地向非极性的甲苯溶液中的转相。UV-Vis和透射电镜等表征结果表明转相后的AuNPs的纳米形貌未发生明显的变化，可成功作为表面增强拉曼光谱（SERS）基底用于巴旦木油脂氧化程度的检测。结果表明，巴旦木油脂位于1655 cm⁻¹处的顺式双键的特征拉曼信号在氧化过程中逐渐减弱；选择酯键的1747 cm⁻¹作为参比信号，其特征峰的相对强度I₁₆₅₅/I₁₇₄₇值与巴旦木的加速氧化时间呈良好线性关系（R²=0.98），SERS光谱结果结合主成分分析法可以用于实际巴旦木样品氧化程度的快速判定和分类。同时本研究也为适用于非水相食品中的SERS基底的制备和应用提供了新的思路。

Bioactives and health benefits of nuts and dried fruits

The oxidation of almonds during the storage and processing would seriously affect their nutrition and quality. The purpose of this study was to establish a sensitive and reliable method for rapid detection of the oxidation of almonds. A rapid and simple phase-transfer of gold nanoparticles (AuNPs) from aqueous solution to toluene was achieved via a strategy of surface ligand exchange. The results of UV-Vis and transmission electron microscopy showed that the morphology of AuNPs after phase-transfer changed no obvious. The AuNPs in toluene could be successfully used as an efficient SERS substrate for detecting the oxidation of almond oil. The characteristic Raman signal of the cis-double bond at 1655 cm⁻¹ of almonds oil gradually decreased during oxidation. Raman signal at 1747 cm⁻¹ of the ester bond was selected as the reference, and the relative intensity of I₁₆₅₅/I₁₇₄₇ showed a good linear relationship with the time of accelerated ageing of almonds (R²=0.98). By virtue of principal component analysis, the developed method was able to quickly and accurately distinguish the almonds with different oxidation levels. This study also provided a new strategy for the preparation and application of SERS substrates for fatty foods.