## 3 Results and Discussion
### Physicochemical Characteristic Analysis  
The physicochemical characteristics, such as moisture content and acid value, of the rancid ZSS samples were also changed significantly, and the results are shown in Table 2.  
Moisture content plays an important role in reflecting the quality and stability of foods and TCMs [17; 18]. Storage conditions with high moisture content are beneficial for the growth of microbes, leading to the production of more free fatty acids and even unpleasant odor [19; 20; 21]. Compared with normal ZSS, rancid samples had been placed in a high-temperature and -humidity condition, resulting in a higher moisture content, and became typical unqualified samples. Water- and alcohol-soluble extracts are important indicators for judging the quality of food and TCMs. For example, water- and alcohol-soluble extracts of _Ganoderma lucidum_ have direct lifespan elongation effects and potential anti-aging properties [22]. Alcohol\(-\)soluble extracts of _Urtica hyperborea_ showed remarkable activity in reducing uric acid [23]. The content of water- and alcohol-soluble extracts in rancid samples was lower than that in normal samples, which was also an important reflection of the deterioration of the quality of ZSS. The pH value is one of the indicators to be considered for foods or TCMs, as the potential influence of pH value on durability and shelf life is an important factor for their quality. The pH value could affect the biological tolerance and stability of formulations [24]. The pH of TCMs could limit the growth of microorganisms, contributing to the stability [25; 26]. For ZSS samples, the pH value of rancid samples was slightly lower than that of normal samples. There was no significant difference between normal and rancid samples. The electrical conductivity can indicate changes in the content of ionic substances such as some ions, proteins, and organic acids [27; 28; 29]. ZSS is rich in fatty oils, and the content of these substances that cause change in electrical conductivity was low, so there was no significant change. Fatty oils are widely distributed in seed TCMs. Many studies suggested that fatty acids were important bio-compounds which took part in complex metabolic pathways [30]. After ZSS became rancid, the content of the fatty oils obtained by the extraction of petroleum \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Sample** & **Color** & **Taste** & **Odor** \\ \hline Normal & Off-white & Slight bitter & Slightly fragrant \\ Rancid & Dark maroon & Bitter and sour & Irritating \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The traditional sensory properties of normal and rancid ZSS samples. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Sample** & **Moisture** & **Water-Soluble Extract** & **Alcohol-Soluble** & **pH Value** & **Electrical** & **Fatty Oil** & **Acid Value** \\  & **Content (\%)** & **Content (\%)** & **Extract Content (\%)** & & **(us/cm)** & **Content (\%)** & **(mg/g)** \\ \hline Normal & 6.60 \(\pm\) 0.06 & 26.35 \(\pm\) 0.15 & 8.69 \(\pm\) 0.04 & 6.09 \(\pm\) 0.02 & 1229 \(\pm\) 1 & 21.30 \(\pm\) 0.30 & 3.90 \(\pm\) 0.15 \\ Rancid & 7.64 \(\pm\) 0.02 * & 20.14 \(\pm\) 0.05 * & 5.64 \(\pm\) 0.06 * & 6.05 \(\pm\) 0.01 & 1256 \(\pm\) 3 & 16.04 \(\pm\) 0.15 * & 18.68 \(\pm\) 0.47 ** \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The physicochemical characteristics of normal and rancid ZSS samples (\(t=6\)). ether showed a significant decrease, which indicated that fat-soluble fatty oils were decomposed in high-temperature and -humidity conditions. This was a common deterioration phenomenon of seed TCMs rich in fatty oils. Related studies found that the content of fatty oils decreased in almond and walnut after rancidity during storage link [31; 32]. The acid value is one of the important safety indicators of seed TCMs. The 2020 edition of the Chinese Pharmacopoeia has established limit standards for the acid value of some TCMs that are prone to rancidity [1].