Investigation of Heating and Freezing Pretreatments on Mechanical, Chemical and Spectral Properties of Bulk Sunflower Seeds and Oil

Abstract

The present study examined the effects of heating and freezing pretreatments on the mechanical, chemical, and spectral characteristics of sunflower seeds and oil under a linear compression process involving a universal compression-testing machine and a pressing vessel of diameter 60 mm with a plunger. The heating temperatures ranged from 40 to 80 °C and freezing temperatures from −2 to −36 °C at constant heating time of 30 min. The pretreated samples of initial height of 80 mm (22.6 × 10−5 m3) were compressed under a preset load of 100 kN and a speed of 5 mm/min. The results showed that oil expression efficiency significantly increased (p < 0.05) with increased heating temperatures but decreased with freezing temperatures. The lowest energy per volume oil of 22.55 ± 0.919 kJ/L was recorded at 80 °C compared to 26.40 ± 0.307 kJ/L noticed at −2 °C and control (25 °C) of 33.93 ± 3.866 kJ/L. The linear regression equations expressing oil expression efficiency, energy per volume oil, peroxide value, and free fatty acid, dependent on heating and freezing temperatures, were described with coefficients of determination between 0.373 and 0.908. Increased heating temperatures increased the UV absorption rate of the oil samples at a wavelength of 350 nm. The study is part of the continuing research on linear compression modeling of all processing factors, whereby the results are intended to be applied to the non-linear process dealing with a mechanical screw press to improve the oil extraction process.

Evaluation of Postharvest Processing of Hazelnut Kernel Oil Extraction Using Uniaxial Pressure and Organic Solvent

“…The correlation efficiency between oil expression efficiency and relaxation time was 91%. The compression and relaxation processes are important for evaluating the oil yield and energy at the compression area and oil expression efficiency without energy at the relaxation phase, which is dependent on several factors such as the volume of kernels, moisture content, vessel diameter, force, and speed, among other factors [48]. Further, from the principles of viscoelasticity, the relaxation time shows how fast the material dissipates after receiving a sudden deformation, that is, when the maximum force is attained, and it can also be used to characterize the elastic and viscous components in the behavior of the material.…”

“…Titration was performed directly with ethanolic KOH (0.1 g/mol) until the color was light pink. Peroxide value was expressed as (µg/g of active oxygen) and free fatty acid was expressed as (mg KOH/g) [1,48,49].…”

“…The percentage kernel oil content ( Figure 1b) was determined to be (64.67 ± 0.01%) using the Soxhlet extraction method [46][47][48]. Based on the procedure, the sample mass of 8 g was ground and packed into a thimble.…”

A lipidomic approach for profiling and distinguishing seed oils of Hibiscus manihot L., flaxseed, and oil sunflower

“…China is among the top 10 countries (fourth position) in production and acreage (Pilorgé, 2020). Sunflower oil is regarded as the high quality oil used in the food industry because of its high content of polyunsaturated fatty acids and vitamin E, and low amounts of allergen factors, anti-nutritional, and toxic compounds (Gürdil et al, 2020).…”

Properties of seeds and oil of sunflower of oleinic type of domestic selection

“…However, in terms of productivity, domestic hybrids are not concede foreign ones, and therefore can be competitive. It should be noted that in new breeding lines and hybrids, not only physicochemical, but also physicomechanical and technological properties are partially changed, which have a direct impact on the conditions for processing oil seeds [5][6][7]. Therefore, the enterprises of the fat and oil industry have an urgent need to have data about physical and chemical parameters of seeds and oils of modern domestic sunflower hybrids for use in their economic activities, to control technological processes and the quality of oilseeds and fat products.…”