When the frequency is more significant than 100 kHz, the energy supplied is less than 1 Wcm\({}^{-2}\). High doses of energy provided to the sample can have the desired effects with the application of ultrasound, but at the same time, it can generate adverse effects such as the degradation of some compounds of interest. The previous statement is why the best effects must be found with the least amount of energy applied. Low-power and high-frequency ultrasound (US) are used to analyze, control, and process, ensuring safe and high-quality food. Its technology uses acoustic energy, nonionizing mechanical energy, and is noninvasive and nonpolluting [8]. This innovative nonthermal technique inactivates microorganisms and enzymes related to degradation in fruits, thus allowing the retention of quality nutrients in fruits and their derivatives. The US's biocidal effect has been attributed mainly to physical principles (cavitation, mechanical effects, micromechanical shocks) and chemicals with the formation of free radicals due to the sonochemical reaction [9]. The technique is considered low-energy, environmentally friendly, and reduces chemical and physical risks, with minimal processing time. The technique is considered low-energy, environmentally friendly, reduces chemical and physical risks, and has minimal processing time [10; 11]. US technology is useful in enhancing the rate of food processing techniques such as cutting, filtration, freezing, extraction, pickling, and drying [12; 13]. The US's mechanical effect facilitates dehydration through the drying process [14]. Moreover, US improves the freezing process by increasing ice crystals formation before the freeze-drying (FD) [15; 16]. Besides, US is a food dehydration method itself, avoiding the decomposition of food due to a low heat application [17] based on the moderate temperatures generated [18]. The effect of ultrasound (US) pretreatment on freeze-dried quince slices was reported by [PERSON] and [PERSON] [19]. They showed higher preservation of bioactive compounds and improved physical properties compared to the untreated fruit samples. [PERSON] et al. [20] demonstrated that ultrasound pretreatment significantly increased the dehydration rate and solid gain of Sanhua plum during osmotic dehydration without affecting the fruits. [PERSON] et al. [21] found that the US pretreatment of honeyberry fruits increased the vitamin C content regardless of the drying technology used. During atmospheric FD of apples, carrots, and eggplants, US application demonstrated a decrease in the drying time and improved the FD process. [PERSON] et al. [22] demonstrated that the US caused no destructive effect on eggplants' antioxidant potential or quality aspects. The US pretreatment of onions before FD increased the flavonoids, quercetin, and phenolic content up to 20%. It improved the antioxidant activity of dried vegetables, only if the US treatment was for short periods, but prolonged sonication harmed the antioxidant activity and antioxidant content compounds [23]. There is evidence of the benefits of ultrasound treatment in the dairy industry, fruits, and processed juices. However, it has been found that it can behave differently in various food matrices, especially concerning the stability of its biomolecules such as ascorbic acid [24]. Therefore, it is necessary to know the low-frequency ultrasound effect on the _gulupa_ pulp as neither the thermal processing nor the sonication effects on the quality parameters of the _gulupa_ have been reported to date.