Impact of High-Pressure Processing on Quality and Safety of High-Oil-Content Pesto Sauce: A Comparative Study with Thermal Processing  
[PERSON]  
1 Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70210 Kuopio, Finland; [EMAIL_ADDRESS] (E.S. ); [EMAIL_ADDRESS] (K.R. ); [EMAIL_ADDRESS] (H.H.) [PERSON]  
2 School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, 70210 Kuopio, Finland; [EMAIL_ADDRESS] (M.H.) [PERSON]  
2 School of Biological Sciences, University of Hong Kong, Pokfulam Road, Hong Kong SAR 99907, China; k  
HPPP is a processing method that kills potential pathogens through the application of high pressure, rather than heat, to food [10]. The processing is typically carried out in sales packaging. HPP is conventionally applied to liquid and solid foods with high water content, over 87%, like ready-to-eat meals, vegetables, fruits, and dairy products [11; 12]. HPP is uniform and instantaneous, unlike thermal processes [13]. The pressure transmission is independent of both mass and time, and, for this reason, the process is short, and minimal nutrient change occurs in food products. Furthermore, the scalability of this technique may be easily and safely transferred from the laboratory to the industry, because HPP is not reliant on the product geometry and size [14]. The European Food Safety Authority (EFSA) has evaluated the safety and efficacy of HPP and believes it is capable of reaching adequate reductions of harmful microorganisms without introducing other safety risks [15]. Since HPP does not denature covalent bonds, it preserves the properties of food products; hence, only the taste, texture, and nutritional value are minimally affected. The technology is active on pathogens such as _Listeria_ spp., _Salmonella_ spp., and _Brucella_ spp., besides proteins associated with microbial replication [16; 17]. The improvement in food safety includes the inhibition of essential enzyme synthesis, damage to the microbial cell membrane, disruption of ion exchange and permeability, and leakage of cellular content [17; 18]. However, it is important to underline the fact that the efficacy of HPP should be measured in various food matrices. HPP is currently utilized for a variety of products. In addition to deactivating microorganisms, it is crucial to maintain the stability of other compounds, particularly fats, after undergoing the process. Some studies have reported that a high lipid content in food materials, such as peanut butter and cheese, increases resistance against spoilage and pathogenic bacteria. This is due to the low water activity rendered by lipids [19; 20]. More recently, lipid fractions have been the focus of research on how they respond to HPP, since harmful secondary products of oxidation can inflict very negative impacts on the final product [21]. Numerous studies have demonstrated that high-pressure processing in high-fat foods leads to increased lipid oxidation [22; 23]. A study on yak fat revealed that applying 600 Mbar pressure significantly increased secondary oxidation and caused changes in the amount of fatty acids, particularly unsaturated fatty acids [24]. Additionally, various studies on lipid oxidation after high-pressure processing in food products containing fat and high fat, such as pork meat and fat [25], salmon [26], cold-smoked salmon [27] and beef muscle [28] have indicated that oxidation can occur at pressures ranging from 200 to 600 Mbar, depending on the nature of the food. The compression resulting from the HPP can increase the temperature of the food by 3 \({}^{\circ}\)C per 100 Mbar [29], and, in high-fat food, the increase is approximately 8 to 9 \({}^{\circ}\)C [30]; after the decompression, the food's temperature returns to its initial level. This temperature rise, along with the composition of fatty acids and time of process, can influence the oxidation rate of lipids in high-fat products [21]. Pesto sauce is a flavorful sauce that is employed in variety of dishes.