## 1 Introduction  
One of the most famous traditional raw milk Portuguese cheeses is _Serra da Estrela_ cheese, which has Protected Designation of Origin (PDO) certification in the European Union. This cheese is manufactured using only raw ewes' milk, _Cynara carduculus_ L. (as coagulant), and salt. The milk used must be from specific ewe breeds (_Bordaleira_ and/or _Churra Mondegueira da Serra da Estrela_), which live in specific geoclimatic conditions of the PDO region rich in natural pastures. The raw milk is processed daily according to strict PDO indications for cheese production, followed by ripening, resulting in a cheese with unique organoleptic characteristics [1]. During ripening, several complex biochemical events occur due to milk microbiota and enzymes' action on lactose, lipids, and proteins, with these having a great impact on cheese characteristics [2, 3]. Lipolysis is an important biochemical process in cheese, with the lipid fraction and the primary products of its degradation, i.e., free volatile fatty acids, playing a crucial role in the development of the distinctive aroma characteristics of _Serra da Estrela_ cheese [4]. There are several studies on lipolysis in _Serra da Estrela_ cheese during ripening [4, 5, 6, 7], yet the lipolysis phenomenon may continue over the storage period (i.e., during transportation and commercialization), particularly in the case of extended storage. More recently, the 33 d ripened _Serra da Estrela_ cheese fatty acids profile and health-related lipid indices from 5 different geographical locations of the PDO region were described by [PERSON] et al. (2019) [8]. High-pressure processing (HPP) is being increasingly applied and studied as a non-thermal alternative process to the conventional heat-based pasteurization processes used for dairy foods, including cheese, registering minimal deleterious effects on quality and a shelf-life extension up to 2-3-fold higher than the non-pasteurized counterparts [9]. However, the effects of HPP on cheese are dependent on the pressure intensity applied, the holding time used, and the ripening stage [10; 11]. Only three studies were found that focused on the effect of HPP on lipolytic features during storage of raw cows' and ewes' milk cheees [12; 13; 14]. Two studies were performed with Casar cheese (raw ewes' milk), and the authors reported results for the total amount of short- (SC-FFAs), medium- (MC-FFAs), and long-chain fatty acids (LC-FFAs) [12; 13]. When cheees were HPP treated (200 MPa and 600 MPa for 5 min and 20 min) at 60 days of ripening, the FFAs levels tended to increase during 240 days of refrigerated storage, but without significant differences among HPP and control cheees [13]. On the other hand, HPP treatment (400 MPa and 600 MPa for 5 min and 20 min) at 14 and 21 days of ripening in cows' milk cheees had significantly lower influence on SC-FFAs, MC-FFAs, and LC-FFAs levels [14]. In general, the effects of HPP on cheese characteristics are dependent on the pressure level applied, the length of treatment, and particularly the stage of ripening at which HPP was applied. For example, to enable the safe storage of _Sera da Estrela_ cheese under refrigeration over a prolonged period of 15 months without modification of its sensory attributes, HPP (450 MPa or 600 MPa for 6 min or 9 min) was applied and its impacts on the cheese properties were assessed [11]. HPP also deaccelerated proteolysis and had little effect on texture parameters and sensorial attributes [10; 11]. However, since some of these changes (especially sensorial attributes) may be related to the lipids state and associated lipolysis extension in cheese, it is important and pertinent to study the effect of HPP on the qualitative and quantitative lipid profiles of cheese immediately after processing and throughout subsequent storage.