Bioactive Compounds, Nutritional Quality and Oxidative Stability of Cold-Pressed Camelina (<i>Camelina sativa</i> L.) Oils

In this study, 29 cold-pressed camelina (Camelina sativa L.) oils, pressed from seeds grown in Poland and purchased directly from local producers, were analyzed. The degree of change in the tested oils&#8217; characteristic hydrolytic and oxidative lipid values was determined. Oxidative stability was determined using the Rancimat and PDSC methods. Fatty acid and phytosterol contents were determined by GC-FID, and tocopherols by HPLC. The analyzed oils were characterized by good, but variable, quality, and met the requirements specified for cold-pressed edible oils. Highly desirable fatty acid composition, low SFA content (about 6%), high &#945;-linolenic acid content (34.7&#8315;37.1%), and optimal PUFA n-3 to PUFA n-6 ratio (1.79&#8315;2.17) were shown. The high nutritional value of camelina oils was confirmed on the basis of high contents of tocopherols (55.8&#8315;76.1 mg/100 g), phytosterols (331&#8315;442 mg/100 g), and carotenoids (103&#8315;198 mg of &#946;-carotene/kg). The optimal nutritional quality indices were as follows: 0.05&#8315;0.07 for the atherogenicity index (AI), and 0.1&#8315;0.2 for the thrombogenicity index (TI). The significant impact of primary (PV) and total oxidation (TOTOX) of camelina oil on oxidative stability was evaluated using Rancimat and PDSC methods. Both methods were also confirmed to be appropriate for the assessment of the oxidative stability of camelina oils

Oxidative Stability Analysis of Selected Oils from Unconventional Raw Materials Using Rancimat Apparatus

This study aimed to evaluate the quality of selected oils from the seeds of herbs and vegetables (basil, fenugreek, coriander, tomato, garden cress, parsley, and dill), especially their oxidative stability. The oils were tested for oxidation degree (acid value, peroxide value, p-anisidine value, TOTOX indicator, and specific extinction under ultraviolet light), colours, content of carotenoid and chlorophyll pigments, fatty acid composition, indicators of lipid nutritional quality, oxidative stability, and oxidation kinetics parameters (Rancimat). Principal component analysis was applied to identify a correlation between the oils’ quality parameters. The results of the fatty acid compositions show that basil oil was a good source of omega-3 fatty acids. Coriander seed oil was found to be the most resistant to oxidation, containing mainly monounsaturated fatty acids. The highest value of activation energy was calculated for fenugreek oil (94.18 kJ/mol), and the lowest was for dill seed oil (72.61 kJ/mol). However, basil oil was characterised by the highest constant reaction rate at 120 °C—3.0679 h−1. The colour determined by the L* parameter and the calculated oxidizability value had the most significant influence on the oxidation stability of the oils, and the correlation coefficients were r = −0.88 and 0.87, respectively

Oxidative Stability and Antioxidant Activity of Selected Cold-Pressed Oils and Oils Mixtures

The aim of the study was to analyse the chemical composition and oxidation stability of selected cold-pressed oils and oil mixtures. The oils were tested for their initial quality, fatty acid composition, total phenolic compounds, DPPH, and ABTS free radical scavenging activity. The Rancimat method was used to assess oxidative stability. The obtained results were subjected to principal component analysis (PCA) to determine the influence of selected chemical properties on the oxidative stability of the oil. It has been found that different factors of oil quality influence the stability of cold-pressed oils. The highest correlation coefficient was noted between the induction time, peroxide value, and TOTOX indicator (r = 0.89). Fatty acid composition, including the percentage of SFA, MUFA, PUFA, and the ability to scavenge ABTS captions radicals, did not significantly affect the oxidative stability of the oils. Black cumin seed oil was the most resistant to the oxidation processes in the Rancimat apparatus, mainly due to the high content of phenolic compounds (384.66 mg GAE/100 g). On the other hand, linseed oil and its mixtures were the least stable. Their fatty acid composition was dominated by a polyunsaturated &alpha;-linolenic fatty acid, significantly reducing the antioxidant resistance

Effect of Deep Frying of Potatoes and Tofu on Thermo-Oxidative Changes of Cold Pressed Rapeseed Oil, Cold Pressed High Oleic Rapeseed Oil and Palm Olein

One of the commonly used food preparation methods is frying. Fried food is admired by consumers due to its unique taste and texture. Deep frying is a process of dipping food in oil at high temperature, usually 170–190 °C, and it requires a relatively short time. The aim of this study was to analyze the thermo-oxidative changes occurring during the deep frying of products such as potatoes and tofu in cold pressed rapeseed oils and palm olein. Cold pressed rapeseed oil from hulled seeds (RO), cold pressed high oleic rapeseed oil from hulled seeds (HORO), and palm olein (PO) (for purposes of comparison) were used. Characterization of fresh oils (after purchase) and oils after 6, 12, and 18 h of deep frying process of a starch product (potatoes) and a protein product (tofu) was performed. The quality of oils was analyzed by determining peroxide value, acid value, p-anisidine value, content of carotenoid and chlorophyll pigments, polar compounds, smoke point, color (CIE L*a*b*), fatty acids content and profile, calculation of lipid nutritional quality indicators, and oxidative stability index (Rancimat). Cold pressed high oleic rapeseed oil was more stable during deep frying compared to cold pressed rapeseed oil, but much less stable than palm olein. In addition, more thermo-oxidative changes occurred in the tested oils when deep frying the starch product (potatoes) compared to the deep frying of the protein product (tofu)

Effect of the Freeze-Dried Mullein Flower Extract (<i>Verbascum nigrum</i> L.) Addition on Oxidative Stability and Antioxidant Activity of Selected Cold-Pressed Oils

The aim of the study was to analyze the influence of mullein flower extract addition on the oxidative stability and antioxidant activity of cold-pressed oils with a high content of unsaturated fatty acids. The conducted research has shown that the addition of mullein flower extract increases the oxidative stability of oils, but its addition depends on the type of oil and should be selected experimentally. In rapeseed and linseed oil, the best stability was found for samples with 60 mg of extract/kg of oil, while in chia seed oil and hemp oil, it was found with 20 and 15 mg of extract/kg of oil, respectively. The hemp oil exhibited the highest antioxidant properties, as evidenced by an increase in the induction time at 90 °C from 12.11 h to 14.05 h. Additionally, the extract demonstrated a protective factor of 1.16. Oils (rapeseed, chia seed, linseed, and hempseed) without and with the addition of mullein extract (2–200 mg of extract/kg of oil) were analyzed for oxidative stability, phenolic compounds content, and antioxidant activity using DPPH• and ABTS•+ radicals. After the addition of the extract, the oils had from 363.25 to 401.24 mg GAE/100 g for rapeseed oil and chia seed oil, respectively. The antioxidant activity of the oils after the addition of the extract ranged from 102.8 to 221.7 and from 324.9 to 888.8 µM Trolox/kg for the DPPH and ABTS methods, respectively. The kinetics parameters were calculated based on the oils’ oxidative stability results. The extract increased the activation energy (Ea) and decreased the constant oxidation rate (k)

α- and β-Carotene Stability During Storage of Microspheres Obtained from Spray-Dried Microencapsulation Technology

This study was aimed at comparing the stability of carotenes (α- and β-carotene) in oil solutions with their stability when spray-dried encapsulation is applied. The carotenes were isolated from carrot. A storage test was subsequently performed. The stability of carotenes in oil solutions was determined with the HPLC method. The color of the samples was also analyzed. The oil solutions of carotenes were microencapsulated with the spray-drying method. A mixture of gum Arabic and maltodextrin was used as a matrix