## 1 Introduction  
Consumer interest in functional diets supporting human health and longevity has rapidly expanded worldwide and consequently demand for healthier and organoletically appealing fresh horticultural products has increased. These changes in consumer behavior have fueled the critical reassessment of the quality of fresh horticultural products as a concept, concisely defined in a recent review as 'a dynamic composite of physicochemical properties and evolving consumer perception, which embraces organoleptic, nutritional and bioactive components' [1]. The bioactive components of fresh horticultural products have been the key ingredients used to generate a wide range of novel functional foods [2]. In addition, horticultural products can provide ingredients of natural-origin able to fulfill the food-preserving functions exerted by synthetic antioxidants [3]. Functional foods and natural food ingredients have thus become major lines of the global food industry, driven by increasing consumer demand, price premiums, and improving market opportunities [4]. Consequentially, growers, extension specialists and scientists have become increasingly interested in new and/or niche horticultural species rich in bioactive metabolites suitable for the production of supplements with nutraceutical, therapeutic or preservative activity [5]. _Perilla frutescens_, L. Britt _Lamiaceae_ (formerly _Labiateatea_), an edible and medicinal plant used traditionally in China, Japan and other Asian countries, has recently gained wider acclaim and high value [6]. Nowadays, its cultivation in the United States, North and South Africa and Europe is widespread, with notable economic returns [7]. The seeds, leaves, and stems of this species contain vitamins, minerals, essential oils and phenolic phytochemicals valued by the food industry as flavoring and antioxidant agents for foods and drinks, and in the pharmaceutical industry as anti-allergic, anti-inflammatory and anti-oncogenic agents [5; 8; 9]. Perilla is present in nature in two, genetically discrete, main chemo-varietal phenotypes: the anthocyanin-rich red-pigmented cultivar known as \"Zi-So\", widely grown in China, and the non-pigmented green cultivar mainly present in Japan and known as \"Shisoyo\" or \"Shiso\" [10; 11]. Red perilla is mainly used for its antioxidant activity and as a food colorant [12], while the green phenotype is mainly used for food, skin cream, and medicines for allergic dermatitis [13]. Chinese and Japanese restaurants widely use Zi-So or Shiso leaves to accompany various fish dishes, in particular with Sa-Shi-Mi (fresh fish slices), not only as a fragrant continent but also because of its bioactive properties that fence food against microbial contamination [14]. The main active phytochemicals of perilla are perillaldehyde, an essential oil which imparts the unique and characteristic flavor to the plant leaves, and rosmarinic acid, a phenolic acid used for culinary and clinical applications [15; 16]. Perilla usually grows in wild areas or is cultured outdoors under growing conditions and practices that do not guarantee standardized quality and bioactive content, which may additionally vary in relation to the genetic material used (e.g., green vs. red perilla) [1; 16]. Given the important properties of this plant and its high economic value, extensive research has been conducted concerning the effects of crop nutrition and environmental conditions on its metabolite profile [17]. However, few scientific papers have described the positive effects of environmental factors on crop performance and especially on the quality traits of this valuable novel crop. In fact, in studies of the modulation of phenolic phytochemicals in both red and green perilla grown under field conditions and harvested in different seasons and years [5; 15], or grown in controlled conditions under 100-300 \(\mu\)E PPFD combined with 1-3 dS\(\cdot\)m\({}^{-1}\) of nutrient solution electrical conductivity [16], only the unfavorable effects of the studied environmental factors were considered.