# Effect of Autochthonous Lactic Acid Bacteria-Enhanced Fermentation on the Quality of Suancai
## 1 Introduction  
Fermented vegetables have a centuries-old history in China, which can be traced back to the Zhou Dynasty. There are a great variety of fermented vegetables in different regions of China; Suancai is a representative fermentation vegetable in northern China [1]. Generally, Suancai is made from cabbages and the manufacture process is putting the cabbages into a jar, adding 2-6% salt and water, and then leaving it for fermentation one month. Suancai is fermented by natural microbial flora which were derived from the materials and the environment. Suancai has become more and more popular due to its peculiar flavor, texture, health functionality, and nutritive value [2]. Many factors could cause immense impacts on the quality of fermented vegetables, such as starters, salt, temperature, and materials. The influence of the materials on the chemical and sensory characteristic of sauerkraut is diverse [3]. Salt and temperature affected the quality characteristic of fermented vegetables through acting on the composition and structure of microflora [4, 5, 6]. The metabolites during the fermentation primarily come from the metabolic capability of microflora in fermented vegetables. The starters could influence the diversity and structure of microflora during the fermentation process. Therefore, the starters were the critical factor in affecting the quality of Suancai. Then,the selection of starters used for inoculation was crucially important for the production of high-quality Suancai. Lactic acid bacteria (LAB), including _Lactobacillus_, _Pediococcus_, _Weissella_, _Leuconostoc_, etc., were detected as the dominant microorganisms during the fermentation of fermented vegetables, such as paocai, Suancai, and suansun [1; 7; 8]. Many starters belonging to LAB were obtained by plate screening and widely used as starters to improve the fermented foods. Many researchers found that LABs were significantly correlated with flavor compounds in fermented vegetables. [PERSON] et al. reported that _Lactobacillus_ was highly associated with 25 flavor compounds and more than 20 flavor compounds were relevant with _Lactobacillus acettolerans_ and _Latilactobacillus sakei_ and enhanced the safety of fermented vegetables [9]. [PERSON] et al. utilized _Latilactobacillus sakei_ to improve vitamin content, increase acidity, and decrease nitrite concentration during sauerkraut fermentation [10]. [PERSON] et al. reported that the inoculation of _Lactiplantiobacillus plantarumum_ (_Lb. plantarumum_) and _Pediococcus pentosaceus_ increased the content of amino acids, alcohols, and aldehydes of Suancai [11]. _Lb. plantarumum_ was also reported to improve ester aromatic substances of Suancai and leads to a typical component [12]. Similarly, [PERSON] et al. found that inoculated with _Lb. plantarum_ had a high abundance of esters, _Leuconostoc mesenteroides_ (_Leu. mesenteroides_), and _Weissella cibaria_ have an augmented contribution in acids and ketones in northeast sauerkraut [13]. However, [PERSON] et al. found that _Lb. plantarum_ inoculation resulted in slow fermentation and massive acid production, while _Leu. mesenteroides_ inoculation could accelerate the fermentation, quickly decrease the pungent odor of the raw materials, and improve the flavor and taste of paocai, and _Levilactobacillus brevis_ (_Lb. brevis_) inoculation contained ethanol and mannitol [8]. [PERSON] et al. found that _Enterobacteriaceae_ and _Lactobacillusaceae_ contributed to the synthesis and metabolism of aroma, flavor, and taste compounds during Chinese Sichuan paocai fermentation [14]. Therefore, the species affiliated to LAB had diverse effects on the quality of fermented vegetables. Thus, it is necessary to systematically investigate the effects of LAB-enhanced fermentation on the quality of Suancai. Therefore, the aim of this study was to determine the effects of different autochthonous _Lb. plantarumum_, _Lb. brevis_, and _Leu. mesenteroides_ on the bacterial community, physicochemical properties, and flavor quality of Suancai.