Optimized extraction and quality evaluation of Niger seed oil via microwave-pulsed electric field pretreatments

Evaluating the physicochemical properties of camelina (Camelina sativa) seed oil obtained through optimized ultrasonic-assisted extraction

The primary limitation associated with oil extraction through pressing is the considerable amount of residual oil in the cake. Therefore, this study focused on employing ultrasound waves to decrease the oil content in camelina seeds. For this purpose, three ultrasound treatment durations (15 to 45 min) were applied, and oil was immediately extracted from the seeds using a screw press at varying speeds (11 to 55 rpm). Various physicochemical tests were conducted on the extracted oil. After identifying the optimal treatments, the fatty acid content and oxidative stability of the samples were determined. Results indicated that longer ultrasound treatment durations led to higher acidity and peroxide values in the samples. In contrast, the oil extraction efficiency and total phenol content initially increased and then declined. Increasing the rotational speed of the screw press decreased total phenol efficiency but increased acidity and peroxide values. Ultrasound pretreatment had no effect on the refractive index of the oils. Based on the process optimization results, ultrasound pretreatment achieved optimal oil extraction from camelina seeds at a treatment time of 21.02 min and a screw press speed of 11 rpm. Under these conditions, the extraction parameters included an efficiency of 34.5 %, an oil acidity of 0.394 % (as oleic acid), a peroxide value of 0.97 meqO2/kg oil, a total phenol content of 122.68 ppm, and a refractive index of 1.4750. Ultrasound pretreatment also reduced oxidative stability from 3.75 h to 3.13 h. Gas chromatography results showed that linolenic acid was the major fatty acid in both treated and control oil samples. As a result, the findings demonstrate that ultrasound pretreatment is an effective method for extracting oil from camelina seeds.

Pulsed electric field treatment improves the oil yield, quality, and antioxidant activity of virgin olive oil

Pulsed electric field (PEF) is an innovative technique used to assist in the extraction of vegetable oils. There has been no research on the effects of PEF on virgin olive oil (VOO) quality and antioxidant activity to date. The present study aimed to analyze the effects of PEF on oil yield, quality, and in vitro antioxidant activity of "Koroneiki" extra virgin olive oil. The results show that the PEF treatment increased the oil yield by 5.6%, but had no significant effect on the saponification value, K232, K270, and ∆K value of the VOO. PEF treatment reduced the oleic acid content by 3.12%, but had no significant effect on the content of palmitic acid, linoleic acid, linolenic acid, arachidonic acid, stearic acid, oleic acid, and palmitic acid. After PEF treatment, the levels of total phenolics, total flavonoids, and oleuropein increased by 7.6%, 18.3% and 76%, respectively. There was no significant effect on the levels of 4 phenolic acids (vanillic acid, p-coumaric acid, ferulic acid and cinnamic acid), 2 lignans (lignans and apigenin), hydroxytyrosol, and 3 pigments (lutein, demagnetized chlorophyll, and carotenoids). In addition, PEF treatment significantly increased the content of tocopherols, with α, β, γ, and δ tocopherols increasing by 9.8%, 10.7%, 13.6% and 38.4%, respectively. The free radical scavenging ability of DPPH and ABTS was also improved. In conclusion, the use of PEF significantly increased the yield of VOO oil as well as the levels of total phenolics, total flavonoids, oleuropein, tocopherol, and in vitro antioxidant activity.

Innovative technologies to enhance oil recovery

The processes for extracting and refining edible oils are well-established in industry at different scales. However, these processing lines encounter inefficiencies and oil losses when recovering crude or refined oil. Palm oil and olive oil extraction methods are used mainly as a combination of physical, thermal, and centrifugal methods to recover crude oil, which results in oil losses in the olive pomace or in palm oil effluents. Seed oils generally require a seed steam conditioning, and cooking stage, followed by physical oil recovery through an inefficient expeller. Most of the crude oil remaining in the expeller cake is then recovered by hexane. Crude seed oil is further refined in stages that also undergo oil losses. This chapter provides an overview of innovative technologies using microwave, ultrasound, megasonic and pulsed electric field energies, which can be used in the above-mentioned crude and refined oil processes to improve oil recovery. This chapter describes traditional palm oil, olive oil, and seed oil processes, as well as the specific process interventions that have been tested with these technologies. The impact of such technology interventions on oil quality is also summarized.

Nutritional Comparison of Sacha Inchi (Plukenetia volubilis) Residue with Edible Seeds and Nuts in Taiwan: A Chromatographic and Spectroscopic Study

Sacha inchi is a source of quality commercial oil in Taiwan. Oil extraction results in sacha inchi residue have not been utilized and not much investigated. Different edible seeds and nuts have different levels of nutrients. This study aims (a) to determine the oil, moisture, ash, protein, carbohydrate, type of fatty acid, resveratrol, and type of sugar in edible seeds and nuts, including sacha inchi residue, and (b) to determine the model to predict the five macronutrients using NIR spectroscopy. The samples used were candlenut, peanut, sesame, sunflower, sacha inchi residue, and black bean. Determination was conducted using NIR spectroscopy, NMR spectroscopy, LC-MS/MS, and HPLC-ELSD. NIR spectroscopy prediction results show that candlenut is rich in oil, and sacha inchi residue is rich in minerals, protein, and moisture. The correct prediction model for oil and moisture is principal component regression, while partial least squares are for ash, protein, and carbohydrates. NMR spectroscopy results showed that all samples were rich in polyunsaturated fatty acids. Sacha inchi residue is rich in omega 3. LC-MS/MS results showed that all samples contained resveratrol, and its highest level was found in sesame. HPLC-ELSD results showed eight types of sugars in the samples. High sucrose was found in sacha inchi residue, sunflower, sesame, and candlenut. The results are expected to provide information on nutrient levels in seeds and nuts to consumers and people who deal with nutrition. Also, results are expected to increase the economic value of sacha inchi residue as a source of diversification of food products in Taiwan.

Niger Seed Oil-Based Biodiesel Production Using Transesterification Process: Experimental Investigation and Optimization for Higher Biodiesel Yield Using Box–Behnken Design and Artificial Intelligence Tools

The present work aims at cost-effective approaches for biodiesel conversion from niger seed (NS) oil by employing the transesterification process, Box–Behnken design (BBD), and artificial intelligence (AI) tools. The performances of biodiesel yield are reliant on transesterification variables (methanol-to-oil molar ratio M:O, reaction time Rt, catalyst concentration CC, and reaction temperature RT). BBD matrices representing the transesterification parameters were utilized for experiment reductions, analyzing factor (individual and interaction) effects, deriving empirical equations, and evaluating prediction accuracy. M:O showed a dominant effect, followed by CC, Rt, and RT, respectively. All two-factor interaction effects are significant, excluding the two interactions (Rt with RT and M:O with RT). The model showed a good correlation or regression coefficient with a value equal to 0.9869. Furthermore, the model produced the best fit, corresponding to the experimental and predicted yield of biodiesel. Three AI algorithms were applied (the big-bang big-crunch algorithm (BB-BC), firefly algorithm (FA), and grey wolf optimization (GWO)) to search for the best transesterification conditions that could maximize biodiesel yield. GWO and FA produced better fitness (biodiesel yield) values compared to BB-BC. GWO and FA experimental conditions resulted in a maximum biodiesel yield equal to 95.3 ± 0.5%. The computation time incurred in optimizing the biodiesel yield was found to be equal to 0.8 s for BB-BC, 1.66 s for GWO, and 15.06 s for FA. GWO determined that the optimized condition is recommended for better solution accuracy with a slight compromise in computation time. The physicochemical properties of the biodiesel yield were tested according to ASTM D6751-15C; the results are in good agreement and the biodiesel yield would be appropriate to use in diesel engines.

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

Seed oil quality is a function of several attributes which include its bioactive compounds, physicochemical and functional properties. These quality attributes are important in seed oil processing as they determine the oil palatability, nutritional and market value. Besides the health, environmental and economic issues related to seed oil extraction using organic solvents such as hexane, other conventional seed oil extraction techniques such as supercritical fluid extraction, enzyme digestion and cold pressing are associated with low recovery of oil and bioactive compounds. Application of novel seeds pretreatments techniques such as microwaving, enzymatic digestion, pulsed electric field and ultrasonication do not only improve the oil yield and quality attributes, but also reduces seed oil extraction time, solvent and energy consumption. Higher phenolic compounds, carotenoids, tocopherols, phytosterols and antioxidant properties in oil from pretreated seeds offer health benefits related to the prevention of cancer, diabetes, obesity, inflammatory and cardiovascular diseases. Increased consumer interest in functional foods and the potential of seeds pretreatments in enhancing the extractability of bioactive compounds from plant material has increased the application of novel pretreatment techniques on diverse oilseeds. This review describes the commonly studied novel seeds pretreatment techniques and critically discusses their influence on the oil physicochemical attributes, oxidation indices, bioactive compounds and antioxidant properties.

Optimized extraction and quality evaluation of Niger seed oil via microwave-pulsed electric field pretreatments

In this study, oil extraction from Niger seeds was evaluated with different microwave irradiation times (0-200 s) and pulsed electric fields (PEF) intensities (0-5 kV/cm) as pretreatments. Then, oil extraction was completed with a screw press at different rotation speeds (11-57 rpm). Quality parameters including extraction efficiency, acidity and peroxide values (PVs), chlorophyll, and phenolic contents along with fatty acid profiles and tocopherol levels of the extracted oils were determined as responses. With enhancements in microwave time, PEF intensity and press rotation, the chlorophyll contents, acidity/PVs, and total phenolics of oils increased similar to oil extraction efficiency although it was reduced later. The optimized conditions selected by response surface methodology were determined as 156.23 s, 1.18 kV/cm, and 20 rpm for microwave time, PEF intensity and press speed, respectively. Fatty acid analysis revealed that linoleic acid was the most predominant fatty acid in the extracted oil. Application of the mentioned pretreatments may lead to a reduction in unsaturated fatty acids and escalation of saturated ones (p < .05). High-performance liquid chromatography results indicated that α-tocopherols are the most common tocopherols in Niger seed oil and microwave-PEF pretreatments may lead to 2.79% increase in tocopherols content.