Abstract:
This study aimed to establish a process for preparing probiotic apricot crisps enriched with a high level of
Lactiplantibacillus plantarum. To achieve this, three pretreatment methods, normal pressure impregnation (NPI), ultrasonic impregnation (UI), and vacuum impregnation (VI), were combined with fermentation technology. The viable count of
L. plantarum in freeze-dried apricot crisps was determined to evaluate the impregnation efficiency of the different methods. Following the optimization of individual process parameters through single-factor experiments, orthogonal experiments were conducted to further optimize multiple factors, including ultrasonic power, ultrasonic time, and fermentation time. In parallel, changes in the apricot cell tissue structure were examined using scanning electron microscopy, and the total sugar, total acid, and total phenolic contents of the fermented apricot crisps were analyzed. The results indicated that UI treatment yielded a viable count of 1.0~2.0×10
7 CFU/g, which was significantly higher than that of the vacuum and normal pressure treatment groups (
P<0.05). The optimal process conditions were determined as follows: ultrasonic power of 125 W, impregnation time of 12 min, and fermentation time of 20 h, under which the viable count of the final product was increased to 1.0~2.0×10
8 CFU/g. Scanning electron microscopy observations revealed that ultrasonic impregnation significantly increased the porosity and pore size of apricot cell tissues, effectively promoting bacterial penetration. After fermentation, the total sugar, total acid, and total phenol contents of the apricot crisps showed significant differences compared with the control group (
P<0.05). This study developed an ultrasonic-fermentation synergistic technology for preparing
L. plantarum-enriched apricot crisps, providing an innovative process for developing high-activity probiotic fruit crisps. It holds important application value for enhancing the added value of apricots and promoting the development of functional snack foods.