# Physico-Chemical Characteristics of _Rosa canina_ L. Seeds and Determining Their Potential Use
## 3 Results and Discussion  
There has recently been growing interest in by-products or waste products from fruit and vegetable processing. Studies on increasingly rational utilization of these materials indicate that they can be viewed as a valuable functional addition to food or as ingredients enriching dairy, meat, or fish products. Owing to their wealth of biologically active compounds (e.g., dietary fibre, phytocompounds, vitamins, and minerals), these materials can also be used as agents for health promotion or personal care [27, 28]. Rosehip seeds are an example of this type of material. Available data on the physico-chemical and nutritional characteristics of the rosehip seed are limited. To the best of our knowledge, ours is the first study to describe the swelling index of rosehip seeds and their color in the CIE L * a * b * color space. The average weight of 1000 rosehip seeds was nearly 20 g (from 19.45 to 20.15 g), which indicates that the seeds were robust and well-developed (Table 1). They had a high dry weight percentage of over 90%. The swelling index is not impressive (in our study it was 2.51) in comparison to typical swelling materials such as chia seeds, for which values have ranged from 8.76 [29] to 17 [30], or flax seeds, with a swelling index of 6.4 [31]. \begin{table}
\begin{tabular}{c c c} \hline
**Thousand Seed Weight** & **Dry Weight (DW) \#** & \\
**[g]** & **[g/100 g]** & **Swelling Index \#** \\ \hline
19.8 \(\pm\) 0.35 & 90.6 \(\pm\) 0.17 & 2.51 \(\pm\) 0.11 \\ \hline \end{tabular}
\end{table} 
Table 1: Physical characteristics of rosehip seeds. The results of color analysis in the CIE L * a * b * color space showed that the rosehip seeds had high luminescence (L * = 61.5), which increased to 68.9 after milling (Table 2). The red/green value (a *) was at a significant but low level of 10.5, while the blue/yellow value (b *) was higher, reaching a value of 28.2 for whole seeds. After milling, both parameters decreased somewhat relative to the values for the whole seeds, by 1.4 and 2.1, respectively, to attain values of a * = 8.8 and b * = 26.2. The overall change in color perception for the observer (\(\Delta\)E) was 7.74, which means that the observer perceives two different colors (\(\Delta\)E > 5) for whole seeds and milled seeds. It is worth noting the color parameters of milled rosehip seeds, especially the high yellow (b *) value, which was 26.2 in our study. This value is optimal for semolina, a material for pasta production [32]. The best pasta material, i.e., durum wheat semolina, presents similar b * values, while the value for common wheat is considerably lower [33]. Thus we can consider adding rosehip seeds to flour made from common wheat and other cereals in order to improve the color of the finished product and enrich it with valuable dietary fibre, which constituted more than 70% of the seeds in our study (Table 3). However, this must be confirmed by appropriate research. In addition, [PERSON] et al. [34] suggest that rosehip seeds can be used in the production of animal feed supplements. [PERSON] et al. [35] reported that 10% inclusion of rosehip seeds in quai diets improved egg consistency. Chemical characterization shows that the rosehip seeds consisted mainly of carbohydrates (79.2%), although this is a somewhat lower value than the content reported by [PERSON] [36], which was 89.07%. Since the carbohydrates in the present study were mainly soluble dietary fibre (71.6%), they can be used as an additive to enrich food with this nutrient or as an ingredient in high-fibre dietary supplements. Moreover, the seeds contained relatively large amounts of ash, which indicates high mineral content (Table 3). Food quality is assessed in part on the basis of its protein content and types of essential amino acids. In these studies, the protein content in rosehip seeds was determined to be 7.67 g/100 g (Table 3).