Novel seeds pretreatment techniques: effect on oil quality and antioxidant properties: a review

Comparative study of different pretreatment methods on peanut oil quality characteristics, anti-oxidation attributes, and phenolic compound compositions

The peanuts heat pretreatment is a crucial step for the following oil extraction, influencing both efficiency and oil quality. The present study investigated the effects of oven roasting (OR, 150 °C, 25 min), infrared ray roasting (IRR, 150 °C, 25 min), and microwave roasting (MR, 700 W, 5 min) on the quality characteristics, anti-oxidation attributes, and phenolic compound compositions of peanut oil. All pretreatment methods changed the physicochemical properties and bioactive compounds of peanut oil. Notably, IRR resulted in the highest oxidation induction index (9.25 h) and enhanced free radical scavenging activity, with increases of 55 % (2,2-diphenyl-1-picrylhydrazyl (DPPH)) and 121 % (2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS)) compared with the control. Furthermore, the free phenolics content (Free-P) increased significantly, particularly with IRR, which was increased 6.00 times. Correlation analysis indicated that Free-P was the primary contributor to the anti-oxidation attributes of peanut oil. The results can provide valuable insights for optimizing peanut oil processing technologies.

Effect of Illite Treatment on Quality Characteristics and Antioxidant Activity of Broccoli (Brassica oleracea L. var. italica) Sprouts

Microgreens have recently gained popularity owing to their reliable economic and nutritional value. This study aimed to increase the quality of microgreen broccoli via treatment with different concentrations (1%, IPB-1; 3%, IPB-3; 5%, IPB-5; or 7%, IPB-7 w/v) of illite-a natural mineral powder. The results showed that the illite treatments considerably increased the content of mineral elements, such as Ca, P, and K; of vitamin C; and of free amino acids; and also increased the total weight of the broccoli sprouts. The content of sulforaphane, a bioactive compound, also increased by up to 47% with illite treatment, with the highest increase being in the IPB-5 group. However, several of the parameters were lower in the IPB-7 group. Aromatic compounds were categorized by functional groups such as hydrocarbons which numbered 36, 30, 34, 28, and 30 in the control, IPB-1, IPB-3, IPB-5, and IPB-7 groups, respectively. We found 16, 15, 15, 13, and 14 sulfides, including dimethyl sulfide, in the control, IPB-1, IPB-3, IPB-5, and IPB-7 groups, respectively. Additionally, aldehydes, comprising seven compounds, were detected in the IPB-1, IPB-3, IPB-5, and IPB-7 groups. Illite treatment significantly increased the activities of antioxidants such as DPPH and the polyphenol content of the microgreens. These results indicate a potential role for appropriate illite doses in microgreen treatment to address multinutrient deficiencies and to increase the quality of microgreen vegetables.

Effect of Pulsed Electric Field Pretreatment on the Concentration of Lipophilic and Hydrophilic Compounds in Cold-Pressed Grape Seed Oil Produced from Wine Waste

Pretreatment of grape pomace seeds with a pulsed electric field (PEF) was applied to improve the extraction yield of cold-pressed grape seed oil. The effects of different PEF conditions, electric field intensities (12.5, 14.0 and 15.6 kV/cm), and durations (15 and 30 min) on the oil chemical composition were also studied. All PEF pretreatments significantly increased the oil yield, flow rate and concentration of total sterols (p < 0.05). In addition, similar trends were observed for total tocochromanols and phenolic compounds, except for PEF pretreatment under the mildest conditions (12.5 kV/cm, 15 min) (p < 0.05). Notably, the application of 15.6 kV/cm for 30 min resulted in the highest relative increase in oil yield and flow rate (29.6% and 56.5%, respectively) and in the concentrations of total tocochromanols, nonflavonoids, and flavonoids (22.1%, 60.2% and 81.5%, respectively). In addition, the highest relative increase in the concentration of total sterols (25.4%) was achieved by applying 12.5 kV/cm for 30 min. The fatty acid composition of the grape seed oil remained largely unaffected by the PEF pretreatments. These results show that PEF pretreatment effectively improves both the yield and the bioactive properties of cold-pressed grape seed oil.

Ultrasonic-ethanol pretreatment assisted aqueous enzymatic extraction of hemp seed oil with low Δ9-THC

In this study, ultrasonic-ethanol pretreatment combined with AEE was developed for oil extraction from hemp seeds. The oil yield reached a maximum of 23.32 % at 200 W ultrasonic power and 30 min ultrasonic time, at this point, the degradation rate of Δ9-THC was 83.11 %. By determining the composition of hemp seed before and after pretreatment, it was shown that ultrasonic-ethanol pretreatment reduced the protein content of the raw material. An enzyme mixture consisting of pectinase and hemicellulase (1/1/1, w/w/w) was experimentally determined to be used, and the AEE extraction conditions were optimized using the Plackett-Burman design and the Box-Behnken. The optimal conditions were determined to be pH 5, total enzyme activity of 37,800 U/g, liquid-solid ratio of 10.4 mL/g, enzyme digestion temperature of 32 °C, enzymatic time of 189 min, and oil recovery of 88.38 %. The results of confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) showed that the emulsion formed during ultrasonic ethanol pretreatment was not uniformly distributed, and the droplets appeared to be aggregated; and the irregular pores of hemp seed increased after pretreatment. The contents of Δ9-THC and CBN in the extracted oil samples were 9.58 mg/kg and 52.45 mg/kg, respectively. Compared with the oil extracted by Soxhlet extraction (SE), the oil extracted by this experimental method was of better quality and similar in fatty acid composition.

Tiger nut (Cyperus esculentus L.) oil: A review of bioactive compounds, extraction technologies, potential hazards and applications

Tiger nut is a tuber of a plant native in the Mediterranean coastal countries, which is of great interest in food industry due to its richness in carbohydrates, lipids, starches, minerals, etc. Recent studies have focused on the analysis of the phytochemical composition of tiger nut, including six essential nutrients, polyphenols, and the extraction of proteins, starches, and phenolic compounds from the by-products of tiger nut milk 'horchata'. Few works were focused on the possibility of using tiger nut oil, a nutritious oil comparable to olive oil, as an edible oil. Therefore, this review discussed some extraction technologies of tiger nut oil, and their effects on the properties of oil, such as bioactive compounds, oxidative stability and potential hazards. The information on the emerging applications of tiger nut oil was summarized and an outlook on the utilization of tiger nut oil by-products were also reviewed.

Oxidative stability, quality, and bioactive compounds of oils obtained by ultrasound and microwave-assisted oil extraction

Vegetable oils are extracted from oilseeds, fruits and other parts of plants. The method used in oil extraction is of great importance, as it affects both the quality of the final product and the environment. It is desirable that the extraction method be minimally costly, fast, environmentally friendly, and produce oil of high quality and quantity. Common oil extraction methods are mechanical pressing and solvent extraction, and these methods have advantages and disadvantages over each other. Mechanical extraction and solvent extraction are controversial due to poor product quality and high environmental impacts. This review presents applications where conventional oil extraction processes are assisted by microwave or ultrasound. It is necessary to evaluate the impact of ultrasound and microwave-assisted extraction on the quality of the extracted oil and also to compare the results with those of conventional extraction methods. For this purpose, this review discusses the effects of microwave and ultrasound-assisted extraction on the physicochemical, oxidation indices, bioactive compounds, and antioxidant properties of oil extracted from oil seeds and fruits. Furthermore, this review provides readers with in-depth information on the mechanisms involved, their use, and the impact of operating conditions. The yield and quality of the oil obtained by these processes can vary depending on parameters such as microwave power, ultrasound power, processing time, and temperature. Finally, the review also discusses the challenges and advantages of the industrial application of these technologies.

Engineered Nanomaterials for Improving the Nutritional Quality of Agricultural Products: A Review

To ensure food safety, the current agricultural development has put forward requirements for improving nutritional quality and reducing the harmful accumulation of agricultural chemicals. Nano-enabled sustainable agriculture and food security have been increasingly explored as a new research frontier. Nano-fertilizers show the potential to be more efficient than traditional fertilizers, reducing the amount used while ensuring plant uptake, supplying the inorganic nutrients needed by plants, and improving the process by which plants produce organic nutrients. Other agricultural uses of nanotechnology affect crop productivity and nutrient quality in addition to nano-fertilizers. This article will review the research progress of using nanomaterials to improve nutritional quality in recent years and point out the focus of future research.

Typical Characterization of Commercial Camellia Oil Products Using Different Processing Techniques: Triacylglycerol Profile, Bioactive Compounds, Oxidative Stability, Antioxidant Activity and Volatile Compounds

The processing technique is one of the key factors affecting the quality of camellia oil. In this study, camellia oils were obtained using four different processing techniques (cold-pressed, roast-pressed, fresh-pressed, and refined), and their triacylglycerols (TAGs) profile, bioactive compound (tocopherols, sterols, squalene, and polyphenols) level, oxidative stability, and volatile compounds were analyzed and compared. To further identify characteristic components in four camellia oil products, the TAG profile was analyzed using UPLC-QTOF-MSE. Five characteristic markers were identified, including OOO (m/z 902.8151), POL (m/z 874.7850), SOO (m/z 904.8296), PPL (m/z 848.7693), PPS (m/z 852.7987). Regarding the bioactive compound level and antioxidant capacity, the fresh-pressed technique provided higher α-tocopherols (143.15 mg/kg), β-sitosterol (93.20 mg/kg), squalene (102.08 mg/kg), and polyphenols (35.38 mg/kg) and showed stronger overall oxidation stability and antioxidant capacity. Moreover, a total of 65 volatile compounds were detected and identified in four camellia oil products, namely esters (23), aldehydes (19), acids (8), hydrocarbons (3), ketones (3), and others (9), among which pressed oil was dominated by aldehydes, acid, and esters, while refined oil had few aroma components. This study provided a comprehensive comparative perspective for revealing the significant influence of the processing technique on the camellia oil quality and its significance for producing camellia oil of high quality and with high nutritional value.

Effect of pretreatments of camellia seeds on the quality, phenolic profile, and antioxidant capacity of camellia oil

Camellia oil is one of the four major woody oils in the world and has high nutritional value due to its richness in monounsaturated fatty acids (MUFAs) and bioactive substances. In order to compare the effects of pretreatments of camellia seeds on the quality, phenolic profile, and antioxidant capacity of camellia oil, three different pretreatment methods, i.e., hot air (HA), steam (ST) and puffing (PU), were used to treat the seed powder in the present study. All three pretreatments changed the internal structure of the camellia seeds. The oil yield was increased after all three pretreatments, with the highest oil yield increased by PU pretreatment (Based on the oil yield, we screened out the best conditions of the three pretreatments, HA pretreatment is 60°C for 40 min, ST pretreatment is 100°C for 15 min, PU pretreatment is 800 rpm). The fatty acids (FAs) of the oil were relatively stable, with no significant changes after three pretreatments. However, all three pretreatments had a significant effect on the acid value (AV), peroxide value (PV), and benzo(a)pyrene (Ba P) of the camellia oil. The PU and HA pretreatments could increase the tocopherol content and the total sterols content in the camellia oil. The ST and PU pretreatments significantly increased the free phenolics (FP) content, all three pretreatments reduced the contents of conjugated phenolics (CP) and insoluble-bound phenolics (IBP) in the camellia oil. The IBP made the most significant contribution to the antioxidant capacities of camellia oil. ST and PU prtreatments increased the antioxidant capacities of the total phenolics in the camellia oil. Eight phenolics in FP, CP, and IBP were significantly correlated with the antioxidant capacities of camellia oil. The results of the present study could provide some theoretical guidance for the pretreatment of camellia seeds for higher oil yield, phenolic content and enhanced antioxidant capacities of camellia oil.

Screening of Thymoquinone Content in Commercial Nigella sativa Products to Identify a Promising and Safe Study Medication

(1) Background: Thymoquinone (TQ) is the leading compound accounting for the pharmacological effects of Nigella sativa seed oil, also known as black seed oil. This study aimed to analyze the TQ content of commercial black seed oils and black seed oil-containing capsules to obtain information on the quality of the products and to find a promising and safe study medication for a putative clinical study. (2) Methods: Six black seed oils and five black seed oil-containing capsules were analyzed. TQ was quantified using a validated method consisting of a simple methanolic extraction and a fast HPLC-UV analysis. (3) Results: The TQ content varied from 3.08 to 809.4 mg/100 g (mean). The highest TQ content was found in a bottled oil, which might be considered for a clinical study. A dose of 4 mL of this oil per day contains 30 mg TQ, which is unlikely to be harmful. Based on the literature, a safe daily TQ dosage appears to be <48.6 mg per adult. (4) Conclusions: These findings suggest that black seed products should be regulated regarding TQ content to enable consumers to buy black seed food supplements of known content for the maintenance and improvement of health.

Effect of oilseed roasting on the quality, flavor and safety of oil: A comprehensive review

Roasting is widely applied in oil processing and employs high temperatures (90-260 °C) to heat oilseeds evenly. Roasting improves the extraction yield of oil by the generation of pores in the oilseed cell walls, which facilitates the movement of oil from oilseed during subsequent extraction. It also affects the nutritional value and palatability of the prepared oil, which has attracted consumers' attention. An appropriate roasting process contributes to better extraction of bioactive compounds, particularly increasing the total polyphenol content in the oil. Correspondingly, extracted oil exhibits higher antioxidant capacity and oxidative stability after roasting the oilseeds due to better extraction of endogenous antioxidants and the generation of Maillard reaction products. Furthermore, roasting process is critical for the formation of aroma-active volatiles and the improvement of desired sensory characteristics, so it is indispensable for the production of fragrant oil. However, some harmful components are inevitably generated during roasting, including oxidation products, polycyclic aromatic hydrocarbons, and acrylamide. Monitoring and controlling the concentrations of harmful compounds in the oil during the roasting process is important. Therefore, this review updates how roasting affect the quality and safety of oils and provides useful insight into regulation of the roasting process based on bioactive compounds, sensory characteristics, and safety of oils. Further research is required to assess the nutritional value and safety of roasted oils in vivo and to develop a customized roasting process for various oilseeds to produce good-quality oils.

Health-Promoting Properties of Borage Seed Oil Fractionated by Supercritical Carbon Dioxide Extraction

Borage (Borago officinalis L.) seed oil is an important source of γ–linolenic acid, which is normally used as a treatment against different pathologies. Since the fractionation of this interesting seed oil has many environmental, economic and biological benefits, two borage fractionation techniques after extraction with CO₂ under supercritical conditions have been studied: precipitation in two cyclone separators and countercurrent extraction column. Both techniques have successfully collected free fatty acids in one fraction: (i) two separators set up in series obtained the highest concentration of free fatty acids in separator 2 at 90 bar/40 °C; (ii) when countercurrent extraction column was used, the acidity index of the raffinate stream was independent from the operating conditions (2.6 ± 0.5%). Furthermore, the composition of the fatty acids, as well as their antioxidant and cytotoxic activities, were determined. The profile of the fatty acids obtained by either of these two methods remained unaltered, so that the crude oil exhibited improved antioxidant and cytotoxic properties. All the extracts obtained in the two cyclone separators at the same pressure/temperature conditions displayed high tumouricidal activity against HL 60 promyelocytic leukaemia cells, even if the extracts at 50% concentration from separator 2 presented a lower inhibitory activity (IC₅₀). The extracts from separator 2 at 90 bar/40 °C exhibited the highest anti-proliferative activity at low doses (IC₅₀ of 0.3 μL/mL for the trypan blue exclusion test). To reach the lethal dose—IC₅₀—with the product obtained through countercurrent column fractionation, a concentration of 2 μL/mL of crude borage oil raffinate was required.