• Ultrasound treatment of freshly squeezed pumpkin juice. • Ultrasound treatment delays color, carotenoid content, and cloud value losses in during storage. • 600 W/10 min completely disintegrated pumpkin juice cells. • 400 W/10 min is the best method to maintain the quality characteristics of pumpkin juice.

6-Gingerol is one of the most pharmacologically active and abundant components in ginger, which has a wide array of biochemical and pharmacologic activities. In recent years, the application of microwave-assisted extraction (MAE) for obtaining bioactive compounds from plant materials has shown tremendous research interest and potential. In this study, an efficient microwave-assisted extraction (MAE) technique was developed to extract 6-gingerol from ginger. The extraction efficiency of MAE was also compared with conventional extraction techniques. Fresh gingers (Zingiber officinale Rose.) were harvested at commercial maturity (originally from Shandong, laiwu, China). In single-factor experiments for the recovery of 6-gingerol, proper ranges of ratio of liquid to solid, ethanol proportion, microwave power, extraction time were determined. Based on the values obtained in single-factor experiments, a Box-Behnken design (BBD) was applied to determine the best combination of extraction variables on the yield of 6-gingerol. The optimum extraction conditions were as follows: microwave power 528 W, ratio of liquid to solid 26 mL·g(-1), extraction time 31 s and ethanol proportion 78%. Furthermore, more 6-gingerol and total polyphenols contents were extracted by MAE than conventional methods including Maceration (MAC), Stirring Extraction (SE), Heat reflux extraction (HRE), Ultrasound-assisted extraction (UAE), as well as the antioxidant capacity. Microwave-assisted extraction showed obvious advantages in terms of high extraction efficiency and antioxidant activity of extract within shortest extraction time. Scanning electron microscopy (SEM) images of ginger powder materials after different extractions were obtained to provide visual evidence of the disruption effect. To our best knowledge, this is the first report about usage of MAE of 6-gingerol extraction from ginger, which could be referenced for the extraction of other active compounds from herbal plants.

This study has investigated the effect of ultrasound (US) as an emerging non-thermal sterilization technique on microbial growth and quality changes in three freshly squeezed pumpkin juices (Cucurbita maxima Duchesne, Cucurbita moschata Duchesne, and Cucurbita pepo L.).The three pumpkin juices were ultrasonicated at different ultrasonic power (0–400 W), time (0–20 min), and temperature (0–30 °C), and the total colony counts of the treated pumpkin juices were less than 5 log CFU/mL, which complied with the food safety and consumption standards. Based on these results, we further investigated the effects of different ultrasonic power (25 kHz, 10 min, 20 °C, 0–400 W) on the physicochemical properties and sensory quality of the three pumpkin juices. The physicochemical properties (color, sugar content, organic acid content, soluble solids, and carotenoids) of treated pumpkin juice were retained or improved to some extent. The antioxidant capacity was also increased by 9.09%, 10.25%, and 16.9% compared to the untreated group. During sonication, the particle size of all samples decreased significantly, the microstructure broke down significantly, and the sensory qualities of pumpkin juice were well preserved after sonication.

Probiotic fermentation with a defined consortium (Saccharomyces cerevisiae, Lactobacillus helveticus, and Lactobacillus delbrueckii subsp. bulgaricus) successfully transformed pumpkin juice into a functional beverage with enhanced bioactivity and appealing aroma. The fermented product achieved a high viable count of 7.37 log CFU mL⁻¹, along with significant increases in vitamin C, total phenolics, flavonoids, and carotenoids compared to unfermented juice. Fermentation also imparted a distinct volatile profile enriched with esters and alcohols—such as phenylethyl alcohol, phenethyl acetate, and ethyl caprylate—which contributed intense fruity and floral notes, as confirmed by OPLS-DA and sensory evaluation. The resulting juice retained its original color (ΔE < 2) and developed desirable rheological behavior. Thus, accordingly the pumpkin juice fermented with the composite probiotics received the highest sensory evaluation. This study demonstrates that composite-culture fermentation effectively enhances the nutritional value, aroma, and sensory quality of pumpkin juice, highlighting its potential as a novel probiotic beverage.