## 1 Introduction  
Owing to the accelerated modern lifestyle and alterations in traditional dietary patterns, several studies have indicated that approximately 40% of daily energy intake is derived from foods with high caloric content and poor nutritional value, such as extruded or fried products. The high consumption of these processed foods is associated with factors contributing with overweight, obesity, and metabolic disorders globally [1, 2]. In this context, there is a trend toward consuming healthy and nutritional foods rich in bioactive compounds with beneficial contributions to consumers [3]. Among the foods in high demand by consumers are fresh-cut and dehydrated fruits and vegetables in the form of snacks or preparing infusions, which are considered convenient and nutritious products, mainly because of their fiber and antioxidant compound contents [4]. In general, this type of product has been widely accepted by consumers, and it is estimated that by 2025, the market value will be 98 billion dollars, with a projected annual increase of 5.8% [5]. Nonetheless, dehydrated products are an alternative to reduce post-harvest fruit and vegetable losses, which are estimated to exceed 40% of the total production worldwide [3]. Apples are one of the most significant and extensively cultivated raw materials for numerous food products globally, both in terms of economic value and production scale, and are consumed in fresh, processed, or minimally processed, including dehydrated products. However, a major drawback of the conventional dehydration process (oven drying) for fruit and vegetables is the oxidation/degradation of vitamin C and bioactive compounds (polyphenols, anthocyanins, and carotenoids), which promote notable color changes and reduce their health benefits and sensory quality [5]. In this context, diverse technologies have been developed based on matrix engineering that enable efficient incorporation of physiologically active components of natural origin into different food matrices. This mitigates the limitations of conventional dehydration processes and improves the functional properties of the dehydrated fruit products, among which vacuum impregnation stands out [6]. Vacuum impregnation (VI) is a processing technology that uses the porous structure of food matrices and is mainly applied as a pretreatment before the dehydration process. During VI, the food is submerged in a solution and subjected to negative pressure to remove gas occluded in the food matrix (vacuum application). Upon restoration of atmospheric pressure, the resulting positive differential pressure drives the transport of the immersion solution into the free spaces of the food matrix via hydrodynamic mechanisms and relaxation phenomena due to pressure changes [6]. This technology is easy to implement, cost-effective, and avoids thermal treatments, thereby preserving valuable compounds in the treated food and impregnation solutions [7]. VI represents a technologically viable alternative for the functionalization of dehydrated vegetables, tubers, and fruits through the incorporation of essential oils, minerals, vitamins, water activity depressants, pH regulators, antimicrobials, texturizers, probiotics, prebiotics, and natural extracts with antioxidant activities [7; 8; 9; 10]. Dried _Hibiscus sabdariffa_ calyx is a potential source of antioxidants among natural extracts with antioxidant properties. _H. sabdariffa_ (HS), also called roselle, karkade, or Jamaica, is a member of the Malvacaee family and is cultivated globally (often in tropical areas). HS calyxes are used for their therapeutic effects in folk medicine and have been studied in clinical trials in both healthy individuals and those with chronic non-communicable diseases such as hypertension, dyslipidemia, and type 2 Diabetes Mellitus [11]. These benefits are mainly attributed to the bioactive molecules (phenolic acids, flavonoids, and anthocyanins).