## 1 Introduction  
Asparagus (_Asparagus officinalis_ L.) is recognized as a nutritional food due to its low caloric content and high concentrations of fiber and antioxidants such as flavonoids, phenolic acids, and vitamins [1, 2], and it is solely eaten in the form of very young, thickened shoots called spears. The two main types are commercially recognized green (and green purple) and white. The green type traditionally has had a much bigger global market. Agronomically, the key difference is whether the shoots are harvested above ground (green) or underground before they reach the surface (white), but botanically, both types are a single species [3]. Global asparagus production is expected to reach 10.7 million metric tons by 2026, with an average annual growth rate of 1.4%. China is the world's largest producer of asparagus, with 8.6 million metric tons in 2021. Peru, Mexico, and Germany rank second, third, and fourth, respectively [4]. The main flavonoid of green asparagus is represented by rutin, which has the highest antioxidant action [5, 6], representing 70% to 90% of the total flavonoid concentration [7]. Rutin has been associated with reducing cholesterol levels and the risk of heart disease and may also have anti-cancer properties [8]. Besides rutin, asparagus contains quercetin and the hydroxycinnamic acids, ferulic and caffeic. Many factors affect the concentration of polyphenols in asparagus, including the cultivar, season, climate, light exposure, and portion of asparagus (top, middle, basal, and root) [6; 9]. Polyphenols, particularly rutin, are present in high concentrations in green asparagus exposed to a high intensity and longer duration of sunlight [9; 10], being produced in plants as a defense molecule against the UV irradiation in sunlight [11]. Asparagus is a highly perishable vegetable, and during storage, the quality of the spear is reduced due to hardening and a series of biochemical reactions [12]. Physiological changes during storage, which cause water and nutritional losses and infection by microorganisms, increase discarding and economic losses. About 30% of postharvest losses are due to spoilage caused mainly by _Escherichia coli_, yeasts, and molds [13]. Lignification is the main cause of hardening, which is a variation in texture, one of the main factors that determines the sensorial and cooking quality of fresh asparagus. Recent investigations have established that hardening is caused by the modification of cell wall composition and structure linkages by ferulic acid [14]. Moreover, the amount of ferulic acid increases during postharvest storage, and in white asparagus, the direct involvement was established of two dimers of ferulic acid, i.e., 8-0-4\({}^{\prime}\)diferulic acid (8-0-4\({}^{\prime}\)-di FA) and 8,5\({}^{\prime}\)-diferulic acid benzofuran (8,5\({}^{\prime}\)-BA di FA), in the increase in hardness during storage [15]. During senescence, phenylalanine ammonia lyase (PAL) is involved, and peroxidase (POD) acts as an antioxidant response in plant tissues. These enzymatic activities are involved in lignin accumulation and in the defense system, triggering a response from the antioxidant enzymes and antioxidant substances naturally present in vegetables [16]. A loss of quality is also noticeable from loss of the bright green color, which, in addition to bending, decreases postharvest quality [17]. Consequently, optimization of postharvest handling and processing, as well as storage conditions, is essential to reduce economic losses and improve asparagus supply chain management. Low temperatures and high humidity are commonly used conditions for many horticultural products to control senescence and increase shelf life [18]. In recent years, other methods for the preservation of fresh products have been developed, including cold plasma [19], ultraviolet (UV) irradiation [20], and gamma irradiation [21]. UV irradiation is widely used as an alternative to chemical sterilization and for the reduction in microorganisms in food products.