Changes of Water Migration and Texture Characteristics of Oil-tea Camellia Seeds during Fresh Storage

Abstract

In order to clarify water migration and textural changes in oil-tea camellia seeds during fresh storage after harvest, low-field nuclear magnetic resonance and magnetic resonance imaging techniques were used to clarify moisture state and distribution law and textural profile analysis was used to monitor the changes in the texture characteristics taking the oil-tea camellia seeds produced in Guizhou Province as test materials. And correlation analysis was carried out. The results showed that the water content of the oil-tea camellia seeds decreased continuously during storage. The water content of Qianyu 1 decreased from 33.86%±3.03% (0 d) to 8.64%±0.24% (56 d), and that of Xianglin 210 decreased from 53.03%±3.36% (0 d) to 10.73%±0.25% (56 d). The rate of decrease in kernel water content was higher than that of the oil-tea camellia seeds. The proportion of non-flowable water was the highest in the oil-tea camellia seeds, whereas that in Qianyu 1 decreased to 62.89% and that in Xianglin 210 decreased to 60.64% after 56 d of storage. The hydrogen proton density image of the fresh oil-tea camellia seeds was bright. Local water loss increased as storage time was prolonged, and the image gradually approached the background color. The fracture and hardness properties of the oil-tea camellia seeds decreased continuously during storage, and that of the seed kernels changed flexural; The springiness of the seed kernels was gradually lost; The cohesiveness of Qianyu 1 changed slightly, while that of Xianglin 210 increased first and then decreased. Correlation analysis revealed a very extremely significant positive correlation between the water content and the total peak area of oil-tea camellia seeds (P<0.01), a significant positive correlation between fracture of oil-tea camellia seeds (P<0.05), and a very significant positive correlation between fracture and hardness (P<0.01). Additionally, a very significant positive correlation was observed between the kernel water content and kernel fracture, kernel hardness and kernel springiness (P<0.01). This study provides basic data for fresh oil-tea camellia seeds pressing technology.

Keywords

• oil-tea camellia seeds
• low field nuclear magnetic resonance (lf-nmr)
• moisture migration
• magnetic resonance imaging (mri)
• texture profile analysis (tpa)