不同储藏条件对玉米水分迁移规律与挥发性成分变化的影响

Effects of different storage conditions on the migration pattern of water and volatile components in Zea mays

中文关键词:  玉米  储藏品质  低场核磁共振技术  挥发性成分  气相离子迁移谱

英文关键词:Zea mays  storage quality  low field-nuclear magnetic resonance  volatile components  gas chromatography-ion mobility spectrometry technology

中文摘要:

      目的 探究不同储藏条件对玉米水分迁移规律及挥发性成分变化的影响, 进而筛选出特征性挥发性成分。方法 采用低场核磁共振技术(low field-nuclear magnetic resonance, LF-NMR)和气相离子迁移谱技术(gas chromatography-ion mobility spectrometry, GC-IMS)研究在解除控温控湿条件下玉米的微观水分、挥发性成分组成及其相对含量的变化情况。结果 随着储藏时间的延长, 水分、脂肪酸值、淀粉、醇溶蛋白指标均发生一定变化。储藏30 d时水分含量达到平衡; 脂肪酸值在30 ℃ 65% RH储藏90 d时数值最大为46.11 mgKOH/100 g, 在储藏120 d脂肪酸值仍为宜存; 20 ℃储藏条件有利于淀粉含量积累; 醇溶蛋白受温度影响较明显; 在65% RH条件下, 随着储藏温度的升高, 结合水分含量逐渐降低, 出现了T20强结合水向T21弱结合水转化, T22强结合水向T23弱结合水转化; 在55% RH条件下, 随着储藏温度的升高, 结合水分含量逐渐降低, 不易流动水和自由水峰与结合水峰变化趋势一致; 样本中的挥发性成分归类为酸类(2种)、醛类(20种)、酮类(15种)、醇类(15种)、酯类(12种)、呋喃类(2种)、烯烃类(3种)、胺类(1种)。结论 随着储藏温度升高, 玉米保持水分的能力逐渐减弱, 而随湿度增加, 其保持水分能力则增强, 高温高湿环境促进醛类和醇类挥发性成分的释放, 而酮类与酯类物质则减少。3-戊酮、1-辛烯-3-酮-M、异戊醇-D、正己醇-D、异戊酸甲酯可作为区分偏高水分玉米霉变的特征性挥发性成分, 为偏高水分玉米霉变鉴定提供参考。

英文摘要:

      Objective To investigate the effects of different storage conditions on the water migration and volatile component changes of Zea mays, and to screen out characteristic volatile components. Methods Low field-nuclear magnetic resonance (LF-NMR) and gas chromatography-ion mobility spectrometry (GC-IMS) technology were used to study the changes in micro moisture, volatile component composition, and relative content of Zea mays under controlled temperature and humidity conditions. Results With the extension of storage time, moisture, fatty acid value, starch, and alcohol soluble protein indicators all undergo certain changes. When stored for 30 days, the moisture content reached equilibrium; the maximum value of fatty acid value was 46.11 mgKOH/100 g when stored at 65% RH for 90 days at 30 ℃, and the fatty acid value was still suitable for storage after 120 days; storing at 20 ℃ was beneficial for the accumulation of starch content; alcohol soluble proteins were significantly affected by temperature; under 65% RH conditions, as the storage temperature increased, the bound moisture content gradually decreased, resulting in the transformation of T20 strongly bound water to T21 weakly bound water and T22 strongly bound water to T23 weakly bound water; under 55% RH conditions, as the storage temperature increased, the bound water content gradually decreased, and the changes in the peaks of non flowing water and free water were consistent with those of bound water; the volatile components in the sample were classified as acids (2 types), aldehydes (20 types), ketones (15 types), alcohols (15 types), esters (12 types), furans (2 types), olefins (3 types), and amines (1 type). Conclusion As the storage temperature increases, the ability of Zea mays to retain moisture gradually weakens, while as the humidity increases, its ability to retain moisture increases. The high temperature and high humidity environment promotes the release of volatile components such as aldehydes and alcohols, while ketones and esters decrease. The 3-pentanone, 1-octen-3-one-M, 1-butanol, 3-methyl-D, 1-hexanol-D, isovaleric acid, methyl ester can be used as characteristic volatile components to distinguish mold growth in high moisture Zea mays, providing reference for the identification of mold growth in high moisture Zea mays.