Wang Jun, Wei Bo-Cheng, Wang Xin, Zhang Yan, Gong Yun-Jin
School of Biology, Food and Environment, Hefei University, Hefei, China.
School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.
Front Microbiol. 2023 Jan 16;14:1113594. doi: 10.3389/fmicb.2023.1113594. eCollection 2023.
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; , , and GG), and evaluated the growth, physiochemical, and aroma characteristics. All three strains exhibited excellent growth potential in the sweet cherry juice; however, and demonstrated more robust acid production capacity and higher microbial viability than 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. and significantly increased 2-heptanone, ethyl acetate, and acetone contents, bringing about a creamy and rummy-like favor, whereas 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.
甜樱桃深受消费者喜爱，近年来中国甜樱桃产量激增。然而，这些水果的脆弱性给扩大生产和运输带来了挑战。为了扩大能够克服这些挑战的甜樱桃产品种类，在本研究中，我们制备了由三种不同乳酸菌（LAB； 、 和 GG）发酵的甜樱桃汁，并评估了其生长、理化和香气特性。所有三种菌株在甜樱桃汁中均表现出优异的生长潜力；然而， 和 表现出比 GG 更强的产酸能力和更高的微生物活力。乳酸是主要发酵产物，苹果酸被LAB显著代谢，这表明微生物代谢从利用碳水化合物向有机酸转变。通过电子鼻（E-nose）和顶空气相色谱-离子迁移谱（HS-GC-IMS）数据的综合分析确定了香气特征。通过HS-GC-IMS共鉴定出50种挥发性化合物，表征了发酵汁的香气特征。LAB发酵后甜樱桃汁的风味发生了变化，果香味总体下降。 和 显著增加了2-庚酮、乙酸乙酯和丙酮的含量，带来了奶油味和朗姆酒般的风味，而 GG 显著增加了2-庚酮、3-羟基-2-丁酮和2-戊酮的含量，产生了奶酪味和黄油味。GC-IMS数据的主成分分析和E-nose结果的线性判别分析能够有效地区分未发酵的甜樱桃汁和分别接种不同LAB菌株的甜樱桃汁。此外，E-nose和GC-IMS结果之间存在高度相关性，为识别不同的甜樱桃汁配方和选择合适的发酵起始培养物提供了理论依据。本研究有助于甜樱桃在食品工业中的更广泛利用，并有助于改善甜樱桃产品的风味。
