# Physico-Chemical Characteristics of _Rosa canina_ L. Seeds and Determining Their Potential Use
## 1 Introduction  
_Rosa canina_ L., known as rosehip, is a perennial shrub of the family Rosaceae, commonly occurring in the temperate climate region of the northern hemisphere. Its fruit, due to its content of nutrients and functional constituents, is a valuable pharmaceutical and food material. It contains large amounts of L-ascorbic acid, as well as flavonoids, phenolic acids, proanthocyanidins, galactolipids, and folate [1, 2, 3]. Rosehip and its preserves are used for nutritional and medicinal purposes. It is consumed raw, cooked, or brewed in various countries [1]. Rosehip has applications in food products such as snacks for children, teas, jellies, marmalade, jam, vinegar, and wine [4, 5]. Folk medicine uses include herbal tea and rosehip syrup [1]. Owing to its content of vitamin C and other bioactive substances,the fruit is used as an anti-flu agent and to support the treatment of kidney, liver, and bladder diseases [4]. The powder produced from the husks of the fruit may improve hip flexion and reduce pain in patients with osteoarthritis [6]. Rosehip extracts are antioxidant, antimicrobial, anti-inflammatory, immunomodulatory, cardioprotective, neuroprotective, anticancer, antibody, and antidiabetic. The extract also has dermatoprotective properties and melanogenesis-inhibiting effects, thereby brightening the skin [1,3]. Oil from rosehip seeds is also valued for its health-promoting properties and applications in personal care [1]. Owing to its high content of unsaturated fatty acids (\(\alpha\)-linolenic, linoleic, oleic, and palmitoleic acid), as well as phytosterols (\(\beta\)-sitosterol, campesterol, stigmasterol, A5 Menasterol, and \(\Delta\)7 Menasterol), tocopherols (\(\alpha\)-, \(\gamma\), and \(\delta\)-tocopherol), carotenoids, and polyphenic compounds (methyl esters of \(p\)-coumaric, ferulic, vanillic, and 4-hydroxybenzoic acid), it can be used as a dietetic and cosmetic ingredient [7,8]. In skin care, the oil is valued as an embilient and a component of formulations with anti-wrinkle, moisturizing, anti-acne, skin hyperpigmentation-reducing, anti-scar, and anti-stretch mark effects [1,3].  
The edible part of the fruit is the hypanthium (outer coating) [9], while the achenes inside it are referred to as the seeds (Figure 1).  
Due to the valuable properties of the rosehip hypanthium, the cultivation of plants of this species is becoming increasingly common. When the hypanthium is harvested, the seeds are a natural waste product containing other valuable substances which can be used in various branches of industry, including the cosmetic, pharmaceutical, and agro-food industries [10,11].  
Many scientific studies have focused on determining the chemical composition and biological properties of rosehips and oil obtained from the seeds, while studies on the whole seeds themselves are scarce [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. Nevertheless, the current trend of utilizing by-products of fruit and vegetable processing, as valuable materials with a nutritionally beneficial composition, significant health-promoting properties, and applications for personal care, suggests the need to conduct and expand this area of research. Therefore, the aim of this study was to investigate the physico-chemical properties of rosehip seeds obtained from a processing plant following the separation of the hypanthium and to determine the potential uses arising from these properties. It is worth emphasizing that our research was conducted on actual waste material from the food processing of rose hips. Furthermore, our research is  
Figure 1: Diagram of a rosehip fruit with a cross-section showing the seeds (drawn by [PERSON]).  
comprehensive and, to the best of our knowledge, there are no studies available describing the swelling index of rosehip seeds and their color in the CIE L * a * b * color space.