## 3 Results and Discussion
### Odor Activity Value Analysis
With (_E_)-2-nonenal having the maximum ROAV control (ROAVmax), other key VFCs in BS3 were nonanal, 2-hydroxy-benzoic acid, pentyl ester, 1-octen-3-ol, 1-methyl salicate, decanal and naphthalene (ROAV \(\geq\) 1). The BS3 have fewer VFCs, which were mainly reflected in the (_E_)-2-nonenal effect of the fruit aroma, and the ROAV values of compounds with other flavors were lower. Compared with BS2, 3-methyl-1-butanol, 1-dodecanol and (_E_)-2-octenal with citrus oil aroma are less. In other studies, among the bamboo shoots fermented with acetic acid, 2,3-butanediol, linalool, octanal and benzene acetaldehyde enhanced the odor intensity of samples; The important flavor effects in the bamboo shoots fermented with water are cis-2-nonen-1-ol and ethyl benzene, which is the product of fermentation and fat oxidation by lactic acid bacteria [31]. In this experiment, clean water was used for fermentation, the pH value in the early stage of fermentation was neutral, and the VFCs produced by microbial fermentation was not prominent. After 72 h of fermentation, the pH value of BS4 decreases. The 2-hydroxy-benzoic acid, pentyl ester acts as ROAVmax. Grass aroma contributes to the main flavor of bamboo shoots, followed by nonanal, methyl salicate, 3-methyl-1-butanol, acetic acid, decanal, naphthalene, \(p\)  
Figure 4: Classification of volatile flavor substances. Volatile flavor substances with a relative odor activity value greater than or equal to 1 are marked in red, and the number in parentheses indicates their relative odor activity value. The darker the graphic color, the greater the contribution of this flavor. cresol, 2-hydroxy-benzoic acid, phenylmethyl ester, 6-methyl-5-hepten-2-one, acetic acid, 2-phenylethyl ester and (_E_)-6,10-dimethyl-5,9-undecadien-2-one. As is shown in Figure 4, due to the fermentation of microorganisms in BS4, the VFCs of esters and alcohols have changed, which is reflected in the 3-methyl-1-butanol, nonanal and methyl salicylate ROAV value increased significantly and has an oily aroma. Studies have shown that _p_-cresol is the main aroma active compound of fermented bamboo shoots and has a grassy aroma, which is probably produced by the degradation of amino acids containing benzene rings such as phenylalanine and tyrosine [31]. Tyrosine is the most abundant amino acid in fresh bamboo shoots [5]. After microbial fermentation, tyrosine is degraded into phenolic compounds, giving the bamboo shoots a grassy smell. The main VFCs in BSJ3 and BSJ4 are acetic acid, which is due to the large amount of acid and carbon dioxide produced during the fermentation of bamboo shoots, while the ROAV value of other flavor compounds is lower than 1 and is not the main flavor contributor. In BSJ5, acetic acid is ROAVmax, and other contributors to strong flavor bamboo shoots soaking solution are: 2-methyl-propanal, butanal, methyl-pyrazine, furaneol and 4-ethyl-phenol, among which methyl-pyrazine and furaneol present a caramel flavor. Although the ROAV value of many other pyrazine compounds is less than 1, they still have a caramel flavor contribution to the BSJ5. These substances are common in coffee and nuts [32]. The increase in caramel aroma compounds in BSJ5 is probably due to the Maillard reaction of protein, amino acid and reducing sugar in bamboo shoots at higher temperatures and longer reaction time. Studies have shown that adding 1.5 g Cysteine and 0.3 g xylose in flaxseed protein hydrolysate can increase its meat flavor through the Maillard reaction [33; 34]. Bamboo shoots after 72 h of fermentation contain high content of amino acids and protein which, in the steam sterilization process, strengthen Maillard reaction to form caramel-flavored compounds, such as pyrazine and pyrrole, giving the bamboo shoot soaking solution a special flavor after sterilization.