Effectiveness of ultrasound pretreatment on dried plant-based food quality: A meta-analysis

บทคัดย่อ

Importance of the work: Ultrasound has promising potential for pretreatment to enhance drying
quality; however, there is a lack of quantitative synthesis across commodities and conditions.
Objectives: To assess the effectiveness of ultrasound pretreatment on dried plant-based products and
to investigate the effects of commodity category, ultrasound pretreatment (UP) parameters and drying
parameters based on subgroup analyses.
Materials and Methods: A meta-analysis of 55 Scopus-indexed studies was conducted using
OpenMEE and applying Hedges’d and a random-effects model. The key quality parameters analyzed
were color, rehydration ratio (RR), flavonoids (TFC), phenolics (TPC), vitamin C, antioxidant capacity
based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant assay and water activity (Aw). Subgroup
analyses examined commodity category, as well as ultrasound and drying parameters.
Results: Ultrasound pretreatment significantly (p < 0.05) improved most quality parameters,
except DPPH and vitamin C. Large effect sizes were observed for RR (3.339), TFC (2.093),
TPC (0.876) and Aw (–2.096). High heterogeneity (inconsistency index >75%) indicated substantial
inter-study variability, necessitating subgroup analyses. These analyses confirmed that commodity
categories, ultrasound pretreatment parameters (equipment, sample-to-water ratio, frequency, power,
duration, temperature) and drying parameters (method and temperature) significantly influenced UP
effectiveness.
Main finding: UP consistently improved multiple quality parameters, especially color stability,
rehydration ratio, bioactive compound retention and water activity. Subgroup analysis revealed
that treatment using 28 kHz, 300 W and 30°C for 30 min, followed by hot-air drying at 60°C,
was particularly favorable for enhancing the drying quality of low-porosity root crops