## 1 Introduction  
Kiwifruit is famous as the king of fruits due to unique flavor and high content of nutrients including minerals, soluble dietary fiber, and vitamin C, the content of which in kiwifruit is 3-5 times more than that in citrus fruits [1, 2]. Furthermore, kiwifruit contains folic acid, lutein, natural inositol, caroten, and other nutrients [3, 4]. It has been confirmed that kiwifruit has many potential health benefits such as anticancer, inhibiting tumor cells, decreasing cholesterol, and promoting heart health [5]. However, kiwifruit is a respiration climacteric fruit, which rot easily and get soft after harvesting. As a consequence, it is necessary that kiwifruit should be further processed and sterilized to get longer shelf life. To date, the post-harvest preservation methods of kiwifruit mainly include low-temperature refrigeration, modified atmosphere storage, 1-methylcyclopropene (1-MCP) treatment, and ozone treatment [6, 7]. Despite the possibility that these techniques could delay the maturity and senescence of kiwifruit, promoting the use of the modified atmosphere storage, cold-chain transportation, and 1-MCP widely is difficult because of the limitations of equipment and technology. Besides, fruits need to be treated with ozone several times during storage, which is very complicated. High concentration of ozone will also accelerate the spoilage of kiwifruit and even cause harm to human. In addition to the above preservation methods, the shelf life of kiwifruit can also be extended by further processing. Kiwifruit products such as kiwifruit juice, fruit wine and kiwifruit jam have attracted great attention worldwide owing to their delicious taste and convenience [8,9]. However, the processing method of kiwifruit products available on the market nowadays mostly is heat treatment, which is easy to operate and at low cost. Meanwhile, heat treatment usually causes serious lost in vitamin C, changes in color, adverse effects on sensory and reduction of volatiles [10,11]. Given that consumers desire for higher quality and fresher products, it is important to seek a sterilization technology that retains the aroma and nutrients of products as much as possible. As a non-thermal sterilization technique, high hydrostatic pressure (HHP) inactivates microorganisms in food by pressure ranges from 100 MPa to 1000 MPa at room temperature, thereby extending the shelf life of food [12,13]. Compared with traditional heat treatment (HT), HHP exerts much less impact on the original aroma, freshness color and vitamins of food [14,15]. The study of [PERSON] et al. [16] suggested that \(-\)a\({}^{\bullet}\) value of HHP-treated spinach puree was higher than that of heat-treated samples during storage, which revealed that HHP could delay the deterioration of green color in spinach puree. Moreover, it has been observed that vitamin C of litchi based mixed fruit beverage was preserved after HHP processing at 400 MPa/600 MPa and 30 \({}^{\circ}\)C for 20 min [17]. Effect of HHP on volatiles in fruits has also been evaluated. Study by [PERSON] et al. [18] showed that HHP processing (800 MPa for 5 min) intensified carrot aroma of fresh orange-lemon-carrot juice. [PERSON] et al. [19] also observed that the content of methyl clavicol and linalool, which are important to flavor of fresh basil, were unchanged after HHP treatment at 860 MPa for 75 \({}^{\circ}\)C as well as 700 MPa for 85 \({}^{\circ}\)C. According to previous studies, it has been confirmed that _(E)_-2-hexenal and hexanal are main characteristic volatiles which contribute to the grassy and fruity notes in kiwifruit [20]. Hexanal imparts grassy and leafy notes to kiwifruit. _(E)_-2-hexenal is responsible for green and fruity aroma [21]. Apart from these two main volatiles, several volatiles also affect flavor of kiwifruit. For instance, ethyl acetate is an odorant with fruit and pineapple aroma while 1-hexanol provides grassy, floral, and soil notes to kiwifruit. Besides, butyl acetate relates to sweet of kiwifruit [22].