# Flavor and Functional Analysis of _Lactobacillus plantarum_
## 1 Introduction  
The apricot belongs to the Rosaceae family and originates from Northwest China [1]. It is a delicious widely eaten fruit all over the world, mainly in Mediterranean countries, South Africa, South America and North America [2]. In China, apricots are mainly distributed in the northwest and eastern regions, the crop planting area and yields are the largest in the Xinjiang region [1]. Apricot has become an important cash crop in Xinjiang with a cultivation history of over 1400 years [3]. The apricots cultivated in Xinjiang include small white apricots, Diaogan apricots, Liguang apricots, etc. The small white apricot has become an important economic fruit in Xinjiang because of its unique flavor and concentrated resource distribution [4].  
The small white apricot is also preferred for its high nutritional value and rich functional properties [5], including benefits such as cancer prevention, beauty and skin care, etc. [6]. Due to seasonal limitations and storage difficulties, small white apricots are often processed into dried apricots, apricot pulp and other products [7]. However, these products fail to retain the full nutritional and flavor characteristics of the original fruit, limiting the development of apricot products to a certain extent. Lactic acid bacteria (LAB) can rapidly grow and reproduce in the intestine. Its products lactic acid and carbon dioxide can rapidly reduce the pH value in the intestinal tract, inhibit the propagation of pathogenic bacteria and bacteria harmful to human health, and thus regulate the balance of intestinal flora [8]. Notably, LAB fermentation can improve the functional and nutritional value of fermented food products by regulating the human intestinal microenvironment [9]. The nutritional and sensory quality of several fermented fruit and vegetable juices has been improved by-fermutation [10]. A compound beverage developed from jujube and dried apricot is well appreciated by consumers for its unique flavor and full taste [9].  
In recent years, with the growing demand for functional foods, the research on probiotic products has increased significantly [11]. LAB fermentation is an economical biotechnology solution to improve the shelf life and nutritional, functional and sensory quality of fermented products [12]. In addition, providing sufficient nutrition, fruits and vegetables are good environments for the growth of LAB [10]. Currently, LAB are widely used in the fermented food industry. Moreover, LAB-fermented fruit and vegetable juices have certain health benefits such as reducing serum cholesterol, inhibiting the growth of intestinal spoilage bacteria, and regulating the balance of microbiota [13]. Although studies have reported the effects of LAB fermentation on the functional characteristics of many plant foods [14], the LAB fermentation effect on volatile flavor compounds, phenolic profiles and antioxidant capacity of apricot juice is largely unknown. In the fermentation process, LAB showed an upward trend. After fermentation, apricot juice obviously has a fermented taste and flavor.  
Accordingly, this study examined the effect of _L. plantarum_ LP56 fermentation on the flavor and nutritional value of apricot juice. The organic acids, phenolic compounds and aromatic compounds of apricot juice were analyzed by HPLC and HS-SPME-GC-MS in seven fermentation stages. Our results provide a theoretical reference for the industrial production of fermented apricot juice.