No abstract

This study aimed to characterize pomegranate seed oil and evaluate its quality and stability parameters against those of linseed oil. The profile of fatty acids and phytosterols and the content of tocopherols were analyzed by gas chromatography and high performance liquid chromatography, respectively. The quality of both oils was assessed as recommended by the American Dil Chemists' Society (ADCS) and stability was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene bleaching (coupled oxidation of β-carotene/linoleic acid) and Rancimat  assays. While α-linolenic acid (52%) was the most abundant fatty acid in linseed oil (LD), punicic acid (55%) was highest in pomegranate seed oil (PSD). Tocopherols and phytosterols (175 and 539 mg/100 g, respectively) were greater in PSD than in LD (51 and 328 mg/100 g, respectively). Both oils met quality standards. The β-carotene bleaching and the DPPH assays showed greater oxidative stability for PSD than for LD. The Rancimat  method, on the other hand, indicated low stability for both oils.

Pomegranate and bitter gourd are two of the few edible fruits that contain conjugated α-linolenic acids (CLnAs) in their seeds. The CLnAs have been associated with many effects that are beneficial to health, such as antioxidant and anti-inflammatory properties. Samples of cold-pressed oils from pomegranate and bitter gourd seeds were evaluated for their phytochemical compositions (fatty acids, tocopherols and phytosterols), their qualities and their stability parameters. The in vitro antioxidant capacities of these oils were evaluated by β-carotene bleaching, DPPH• scavenging, oxygen radical absorbance capacity (DRAC) and ABTS• scavenging assays. Several differences in the compositions of the fatty acids, the bioactive compounds and the antioxidant capacities were observed for the two seed oils (pomegranate and bitter gourd) when they were assessed. The highest contents for the phytochemicals (conjugated α-linolenic acids, β-sitosterols, γ-tocopherols) and the in vitro antioxidant capacities were found in the pomegranate seed oil, when using both the DPPH• and ABTS• methods. These results have indicated that seed oils with bioactivity properties can be a challenge for more research, in order to address absorption, health benefits and technological applications.

The conditions for the solid-liquid extraction of the antioxidant polyphenol compounds from yellow passion fruit seeds were optimized by response surface methodology with the following variables as the extraction parameters: extraction time (12.8-147.2 min), ethanol concentration (13-97%), and temperature (16.4-83.6 °C). The polyphenol content and antioxidant capacity, which were assessed by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, oxygen radical absorbance capacity, β-carotene bleaching assay, and ferric reducing antioxidant power assay, were considered dependent variables. The association of the dependent variables was effective for explaining the effect of the independent variables within a determination coefficient (R) range of 0.88-0.96. A moderate-to-strong correlation for the polyphenol content and antioxidant capacity by the investigated methods was established, and optimized conditions were employed to maximize this response. Extraction was carried out at 80 °C using 70% ethanol concentration for 30 min, which was the most efficient condition to obtain an extract with high concentrations of polyphenolic compounds (3.12 g gallic acid equivalent/100 g seed dry basis) and a strong antioxidant capacity. The stilbene piceatannol was the major compound identified by liquid chromatography-electrospray ionization-tandem mass spectrometry (3.68 g/100 g seed dry basis). These results reinforce that agro-industrial waste demonstrates potential as a source of bioactive compounds, with implications in human health as well as in food and chemical industries.

Background Characterization of food lipids has triggered the development of applications for the food and health industries. Thus, the lipid profiles of an increasing number of fruits and their seeds have been characterized and numerous bioactive components have been isolated. The bitter gourd seed oil has aroused great interest because it contains relevant amounts of conjugated fatty acid α-eleostearic acid (C18:3 9c11t13t), a positional and geometric isomer of α-linolenic acid. The aim of this paper was to evaluate the phytochemical composition and quality parameters of the seed oil of bitter gourd grown in Brazil. Methods Bitter gourd was purchased from CEAGESP (Brazilian company of fresh food storages and warehouses). Seeds were lyophilized, and their oil was extracted using the Soxhlet and Folch extraction methods. The profiles of fatty acids and phytosterols were analyzed by gas chromatography, and the acidity and peroxide values were evaluated by methods of the American Oil Chemists’ Society (AOCS). Results The Soxhlet extraction (40 % w/w) resulted in a higher yield of bitter gourd seed oil than the Folch extraction (16 % w/w). For both methods, α-eleostearic acid (56 and 58 %) was the major lipid in bitter gourd seed oil, followed by stearic acid (C18:0; 32 and 27 %). The oil displayed high content of phytosterols (886 mg/100 g), mainly β-sitosterol, and low acidity and peroxide values. Conclusions Bitter gourd seed oil from Brazil is an oil of good quality and its high contents of α-eleostearic acid and phytosterols with potential health-beneficial properties make it an attractive plant byproduct.