Aroma profiles of sweet cherry juice fermented by different lactic acid bacteria determined through integrated analysis of electronic nose and gas chromatography–ion mobility spectrometry

Abstract

Sweet cherries are popular among consumers, with a recent explosion in sweet cherry production in China. However, the fragility of these fruits poses a challenge for expanding production and transport. With the aim of expanding the product categories of sweet cherries that can bypass these challenges, in this study, we prepared sweet cherry juice fermented by three different lactic acid bacteria (LAB; Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus rhamnosus GG), and evaluated the growth, physiochemical, and aroma characteristics. All three strains exhibited excellent growth potential in the sweet cherry juice; however, Lactobacillus acidophilus and Lactobacillus plantarum demonstrated more robust acid production capacity and higher microbial viability than Lactobacillus rhamnosus GG. Lactic acid was the primary fermentation product, and malic acid was significantly metabolized by LAB, indicating a transition in microbial metabolism from using carbohydrates to organic acids. The aroma profile was identified through integrated analysis of electronic nose (E-nose) and headspace gas chromatography–ion mobility spectrometry (HS-GC–IMS) data. A total of 50 volatile compounds characterized the aromatic profiles of the fermented juices by HS-GC–IMS. The flavor of sweet cherry juice changed after LAB fermentation and the fruity odor decreased overall. Lactobacillus acidophilus and Lactobacillus plantarum significantly increased 2-heptanone, ethyl acetate, and acetone contents, bringing about a creamy and rummy-like favor, whereas Lactobacillus rhamnosus GG significantly increased 2-heptanone, 3-hydroxybutan-2-one, and 2-pentanone contents, generating cheesy and buttery-like odors. Principal component analysis of GC–IMS data and linear discriminant analysis of E-nose results could effectively differentiate non-fermented sweet cherry juice and the sweet cherry juice separately inoculated with different LAB strains. Furthermore, there was a high correlation between the E-nose and GC–IMS results, providing a theoretical basis to identify different sweet cherry juice formulations and appropriate starter culture selection for fermentation. This study enables more extensive utilization of sweet cherry in the food industry and helps to improve the flavor of sweet cherry products.

Effect of Lactobacillus rhamnosus and Saccharomyces cerevisiae on the flavour profile of sweet fermented glutinous rice (Jiu Niang)

“…In contrast, malic acid and fumaric acid were not detected in LR, SC, and SL samples, indicating their likely consumption by Saccharomyces cerevisiae and Lactobacillus rhamnosus during fermentation. Comparable findings were observed in the sweet cherry juice fermented with Lactobacillus rhamnosus, as reported by Wang et al (2023a). The malic acid content decreased from 323.15 to 0.54 mg L À1 , and the fumaric acid content The results represent the mean value of three replicates.…”

“…The LTQ‐Orbitrap MS/MS system (Thermo Fisher Scientific, Waltham, MA, USA) coupled with the ACE Excel 3 super C18 column (100 mm × 2.1 mm, 1.7 μm) was utilised to analyse non‐volatile acids, namely malic acid, citric acid, lactic acid, fumaric acid, succinic acid, and tartaric acid, based on our prior research with specific adaptations (Wang et al ., 2023a). Each sample was centrifuged and filtered through a 0.22 μm membrane before loading.…”

“…In recent years, lactic acid bacteria (LAB) have proven to positively affect the overall taste of foods (Virdis et al ., 2021). Lactobacillus rhamnosus is a common LAB strain widely used in the fermentation process of fruits, dairy products and cereals (Sun et al ., 2019; Masiá et al ., 2021; Wang et al ., 2023a). Multiple studies have documented the benefits of employing Lactobacillus rhamnosus in the bioprocessing of foods (Walker & Stewart, 2016; Masiá et al ., 2021; Pei et al ., 2022).…”

Influence of lactic acid fermentation on the phenolic profile, antioxidant activities, and volatile compounds of black chokeberry (Aronia melanocarpa) juice

“…The aldehydes are the typical volatile compounds in many fruits, which present a low threshold. Higher aldehydes in food may result in an unpleasant flavor, whereas a lower content is associated with a pleasant aroma (Wang, et al., 2023a). Benzaldehyde‐D mainly provided nutty and cherry flavor and was the main volatile in the black chokeberry juice.…”

“…The colony counts were analyzed in accordance with our previous study (Wang et al., 2023a). Briefly, 1 mL of fermented black chokeberry juice was serially diluted to 10 −6 , 10 −7 , and 10 −8 , respectively.…”