To improve the resource utilization of Dendrobium officinale leaves, this study aimed to investigate the effects of lactic acid bacteria fermentation on the quality and flavor components of a blueberry-D. officinale leaf composite beverage, with the goal of developing a fermented beverage with unique taste, nutritional value, and health benefits. Using blueberries and D. officinale leaves as the main raw materials and Lactobacillus plantarum as the fermentation strain, a composite fermented beverage was prepared. Single-factor and orthogonal experiments were conducted to optimize the volume ratio of blueberry juice to D. officinale leaf juice, addition mass fraction of sugar, inoculation volume fraction of Lactobacillus plantarum, and fermentation time, thereby determining the optimal fermentation parameters. The results showed that the optimal fermentation parameters were a blueberry juice to D. officinale leaf juice ratio of 1:1, addition mass fraction of sugar of 6%, inoculation volume fraction of L. plantarum of 2%, and fermentation time of 48 h. Under these conditions, the fermented beverage exhibited a pleasant sweet-sour taste, with a soluble solid content of 9.47%, total sugar content of 56.28 mg·mL-1, total phenolic content of 1.80 mg·mL-1, anthocyanin content of 13.21 mg·L-1, and a sensory score of 84.50. Compared to the pre-fermentation state, the DPPH, ABTS+, and hydroxyl radical scavenging rates increased by 13.50%, 11.00%, and 17.88%, respectively. Additionally, 73 volatile flavor compounds were detected, primarily esters, alcohols, aldehydes, and phenols, with higher concentrations of ethyl nonanoate, ethyl acetate, ethyl butyrate, linalool, 1-nonanol, 2-ethyl-1-hexanol, 1-heptanol, and 1-pentanol. Fermentation promoted the conversion of acids to esters, significantly increasing the ester content and imparting a fresh, sweet, and smooth taste to the beverage. Lactic acid bacteria fermentation significantly improved the quality and flavor of the blueberry-D. officinale leaf composite beverage, enhancing its antioxidant activity and nutritional value. This study provides a new approach for the deep processing and high-value utilization of agricultural by-products, demonstrating significant application potential.
