## 1 Introduction  
Grapes are popular among consumers for their beautiful appearance, delicious taste, and high nutritional value, and thus they have been honored as \"the queen of fruits\" [1]. They is rich in a variety of bioactive substances, such as polyphenols, flavonoids, anthocyanins, plant fiber, and various vitamins and minerals [2], which can protect the skin and cardiovascular and nervous systems as well as providing anti-bacterial and anti-inflammatory effects [3]. Grape juice is one of the most common deep-processing products of grapes, which can reduce albumin and sodium chloride in the kidneys, enhance liver function, promote bile secretion, promote digestion [4], soften blood vessels [5], improve neurasthenia, alleviate excessive fatigue, and prevent heart disease and cancer [6, 7]. Hence, in China, grape juice has a reputation as a \"plant milk\". Sterilization is one of the key operations in grape juice processing, and thermal sterilization methods are the most commonly used techniques. At present, conventional thermal sterilization (CTS) is still widely used in the processing of grape juice [8]. Although it can effectively inactivate microorganisms and undesirable enzymes, contributing to a longer shelf life for the fruit juice, high temperature treatments lead to sensory deterioration, a loss of nutrients and functional substances, and a significant reduction in the quality of the fruit juice [9]. These deficiencies, coupled with the increasing consumer awareness about health and nutrition, prompted the food industry to explore new sterilization and preservation technologies. Hence, nonthermal sterilization technologies have become a research focus in the field of food processing in recently years. Ultrasound (US) treatment is one of the innovative nonthermal sterilization technologies that could not only ensure the safety but also improve the quality of liquid food [9]. The effects of US inactivated microorganisms and enzymes are mainly dependent on the mechanical effects (turbulence, liquid circulation, shock waves, high-speed shear force, and micromechanical shocks) and/or chemical effects (formation of free radicals and decomposition of water vapor in the bubbles) of cavitation [10]. The shear-induced cell wall destruction, cell membrane damage, content release, and DNA damage from free radicals generated by thermolytic dissociation leads to overall deactivation [11]. Furthermore, US could also effectively retain beneficial nutrients and bioactive compounds, especially heat-sensitive components, while decreasing the microbial load and endogenous enzyme activity and minimally affecting the physiochemical and sensory indexes in liquid foods [12]. However, using US alone still had some disadvantages, such as high energy consumption, which was mainly due to the high-power, long-term over-processing of US treatment [13], etc., which limited the application of US in juice processing. Meanwhile, coupling the US with other sterilization techniques showed good application potential in the preservation of various juices [11; 14; 15; 16; 17]. A variety of US-combined sterilization technologies not only show synergistic effects in inactivating microorganisms and enzymes, reducing the high energy cost of US, but also maintained the nutritional, organoleptic, and physicochemical properties of juices, even better than US treatment alone. Currently, the US-combined sterilization technologies that have been reported are thermosonication (TS, that is, US plus mild heat) [18; 19], manoonsication [20], manothermosonication [15], US plus gassing [16], US plus irradiation [17], US plus pulsed electric field [21], and US/TS plus antibacterial agents [22], etc. TS and US/TS plus an antibacterial agent (such as nisin) have been widely addressed [18], mainly due to their simple operation and low cost.