The rational exploitation of byproducts is important from the point of view of their potential applicability in various fields. In this study, the possibility of further processing of blackcurrant seeds (BCs), which are a byproduct of fruit processing, was investigated. BCs were used as a material for the extraction of oil on a semi-industrial scale, and the residues were assessed in terms of their potential application in skin care products. Supercritical fluid extraction (SFE) using CO₂ at pressures of 230 and 330 bar and extraction temperature of 40 °C was exploited for isolation of oil, and the products were characterised taking into account lipophilic constituents. After 120 min, the oil yields were 19.67% and 20.94% using CO₂ at 230 and 330 bar, respectively, which showed that SFE was an effective method on a semi-industrial scale, taking into account the extraction yield. The oils had similar fatty acid compositions with a high percentage of linoleic acid (ca. 43%); however, tocopherols and carotenoids were most abundant in the oil obtained at 230 bar. It was also found that the composition of the SFE oils was comparable with that of cold-pressed oil, which shows that supercritical fluid extraction provides a high-quality product; therefore, it can be an alternative to cold pressing. Furthermore, the chemical compositions of the extracts from the oil isolation residues were established using UPLC-MS, and the impact of the extracts on human skin fibroblasts was assessed using the MTT and NR assays. The quantitative analysis revealed that the residues contained high amounts of polyphenolic acids, including gallic, protocatechuic, and hydroxybenzoic acid derivatives, as well as flavonoids, especially quercetin and kaempferol glucoside. Moreover, it was found that the extracts were nontoxic and exerted a stimulatory effect on cell metabolism. Therefore, they can be a valuable additive to natural plant-based cosmetics. Our results showed that blackcurrant seeds, regarded as a byproduct, can be a valuable material for further use.

Paprika Capsicum annuum L. contains useful molecules such as carotenoids and polyunsaturated fatty acids, which are considered high-value functional and health ingredients. To obtain these compounds, paprika was extracted using different methods (Soxhlet, SC-CO_2, and SC-CO₂ with co-extractant) and at different parameters. The results showed that the carotenoid content decreased with the addition of the co-extractant while the fatty acid content and yield increased. It was found that the highest carotenoid content (capsanthin > β-carotene > capsorubin > zeaxanthin > β-cryptoxanthin > violaxanthin) was obtained at 50 °C/45 MPa for SC-CO₂ extraction. Paprika extract rich in polyunsaturated fatty acids (linoleic, oleic, and α-linolenic acid) was obtained at 40 °C/25 MPa for SC-CO₂ with co-extractant. The PUFA/SFA ratios for paprika extract were in agreement with the recommendations of nutritional guidelines. The use of SC-CO₂ for the extraction of Capsicum annuum allowed us to obtain a high-quality, rich in carotenoids and polyunsaturated fatty acids, extract that can be used as a substrate in the industry.

Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. is a medicinal plant used in Traditional Chinese Medicine (TCM) for thousands of years. However, due to the overexploitation, this species is considered to be endangered and is included in the Red List, e.g., in the Republic of Korea. Therefore, a new source of this important plant in Europe is needed. The aim of this study was to develop pharmacognostic and phytochemical parameters of the fruits. The content of polyphenols (eleutherosides B, E, E1) and phenolic acids in the different parts of the fruits, as well as tocopherols, fatty acids in the oil, and volatile constituents were studied by the means of chromatographic techniques [HPLC with Photodiode-Array Detection (PDA), headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS–SPME/GC–MS)]. To the best of our knowledge, no information is available on the content of eleutherosides and phenolic acids in the pericarp and seeds. The highest sum of eleutheroside B and E was detected in the whole fruits (1.4 mg/g), next in the pericarp (1.23 mg/g) and the seeds (0.85 mg/g). Amongst chlorogenic acid derivatives (3-CQA, 4-CQA, 5-CQA), 3-CQA was predominant in the whole fruits (1.08 mg/g), next in the pericarp (0.66 mg/g), and the seeds (0.076 mg/g). The oil was rich in linoleic acid (C18:3 (n-3), 18.24%), ursolic acid (35.72 mg/g), and α-tocopherol (8.36 mg/g). The presence of druses and yellow oil droplets in the inner zone of the mesocarp and chromoplasts in the outer zone can be used as anatomical markers. These studies provide a phytochemical proof for accumulation of polyphenols mainly in the pericarp, and these structures may be taken into consideration as their source subjected to extraction to obtain polyphenol-rich extracts.

Recently, there has been an increased interest in the valorization of byproducts generated during fruit processing. An example of this is the waste produced during the processing of strawberries. For instance, it has been evidenced that strawberries seeds can be a valuable source of oil. The goal of this paper was to investigate the potential of strawberry seed residues after oil extraction (defatted seeds) as a source of phenolics with possible cosmetic applications. The components were recovered using water and ethanol mixture, assisted by heat, ultrasound, and microwave. The extracts were characterized through ultra-high performance liquid chromatography with spectrophotometric and mass detectors (UPLC-DAD-MS), and the biological properties of the phenolic-rich fraction were assessed using antioxidant tests and a cell viability assay on human skin fibroblasts. The study revealed that defatted strawberry seeds are rich in low molecular weight phenolics, specifically in tiliroside, kaempferol 3-glucoside, and ellagic acid. Furthermore, the phenolic-rich fraction was effective in scavenging free radicals in human skin fibroblasts and showed cytoprotective activity against oxidative stress. This evidence suggests that defatted strawberry seeds are a valuable material for further processing to obtain a beneficial additive for skincare products.

Supercritical carbon dioxide extraction was used to extract carotenoids from dry paprika Capsicum annuum. Studies regarding the effect of process parameters, including pressure (25–45 MPa), temperature (40–60 °C), and time (10–110 min), were carried out using response surface methodology. It was found that under optimal conditions (pressure of 45 MPa, temperature of 50 °C, and time of 74 min), the extract yield was 10.05%, and the total content of carotenoids in the extract was 4.21%, in good agreement with the predicted values (10.24% and 4.24%, respectively). Composition analysis showed that paprika extract mainly consisted of linoleic acid. There was no significant difference between the fatty acid content of the extracts obtained by SC-CO₂ extraction and n-hexane Soxhlet extraction. For functional purposes, the effect of storage conditions and time on the quality of paprika extract was also specified.