Heating effects on physicochemical characteristics and antioxidant activity of flaxseed hull oil (Linum usitatissimum L)

Investigation into the Reduction of Palm Oil in Foods by Blended Vegetable Oils through Response Surface Methodology and Oxidative Stability Tests

Recently, there has been a significant transition in the dietary preferences of consumers toward foods containing health-promoting compounds. In addition, as people's environmental awareness increases, they are increasingly looking for sustainable solutions. Palm oil, an oil used extensively by the food industry, does not fit these criteria. This study investigated the development of a complex oil blend consisting of commonly used vegetable oils such as corn, rapeseed, sunflower, and palm oil. The aim was to find the optimal blended oil and compare this combination with palm oil in terms of its oxidative stability, antioxidant capacity, and the composition of bioactive compounds (i.e., fatty acids, tocopherols, and carotenoids). Palm oil was found to have greater oxidative stability as a result of its increased concentration of saturated fatty acids. The optimal blended oil, which consisted of corn and rapeseed oil at a ratio of 4:3 w/w, inhibited the superior antioxidant activity, showing a ~33% increase in DPPH• inhibition activity. ATR-FTIR spectra further verified the existence of a significant quantity of saturated fatty acids in palm oil and unsaturated fatty acids in the blended oil. Finally, several correlation analyses revealed interesting connections between oil samples and investigated parameters. This work has the potential to establish a basis for the mass production of oil blends that possess high concentrations of antioxidant compounds and reduce the use of palm oil.

Characterization of New Egyptian Linseed Varieties and the Effects of Roasting on Their Pigments, Tocochromanols, Phytosterols, Omega-3 Fatty Acids, and Stability

The purpose of this study was to explore the effects of roasting linseeds on the pigment, lipid profile, bioactive components, and oxidative stability of the extracted oils. The linseed varieties Giza 11, Giza 12, Sakha 3, and Sakha 6 were roasted at 180 °C for 10 min, and the oils were extracted by cold pressing. The results showed that, after roasting, there was an increase in oil percentage and peroxide value, as well as small increases in p-anisidine and acid values. Roasting also caused an increase in chlorophyll content, while lutein and β-carotene tend to slightly decrease, except in the Giza 11 variety. The total phenolics content was markedly enhanced after roasting. Omega-3 fatty acids were not affected by the roasting process. The total amounts of tocochromanol were found to decrease in the Giza 12 and Sakha 6 varieties after roasting. Plastochromanol-8 increased in all varieties after roasting. The phytosterol composition was minimally affected by roasting. Roasting enhanced the stability of the extracted oils, increasing the induction period and decreasing EC50 values. These results may thus help to discriminate between the different linseed varieties and serve to recommend the use of roasting to enhance the oxidative stability of extracted oil.

Determination of Maximum Oil Yield, Quality Indicators and Absorbance Spectra of Hulled Sunflower Seeds Oil Extraction under Axial Loading

The present study aims to estimate the maximum oil yield of hulled sunflower seed samples in a uniaxial process under a load of 40 kN and speed of 4 mm/min. The oil samples were assessed for their quality parameters and spectra curves within the wavelength range of 325–600 nm. The results show that heating temperatures in the range of 40 °C to 80 °C increased the oil output; however, a maximum oil yield of 48.869 ± 6.023% with a minimum energy of 533.709 ± 65.644 J at the fifth repeated pressing was obtained from the unheated sample compared to the heated samples. The peroxide values ranged from 6.898 ± 0.144 to 7.290 ± 0.507 meq O₂/kg, acid values from 1.043 ± 0.166 to 1.998 ± 0.276 mg KOH/g oil and free fatty acid values from 0.521 ± 0.083 to 0.999 ± 0.138 mg KOH/g oil, which were within the recommended quality threshold. There were significant spectral differences among the oil samples. A single absorbance peak was observed at 350 nm for all oil samples, indicating low levels of pigment molecules in the oil. The study revealed the need for repeated pressings to recover the considerable residual oil remaining in the seedcake after the first pressing.

A Comprehensive Study of Lupin Seed Oils and the Roasting Effect on Their Chemical and Biological Activity

The present investigation aimed to study the impact of roasting on the chemical composition and biological activities of sweet and bitter lupin seed oils. Lupin oils were extracted using petroleum ether (40–60) with ultrasonic assisted method. Lupin Fatty acids, phytosterols, carotenoids, and total phenolic contents were determined. In addition, antioxidant, antimicrobial, and antifungal activities were evaluated. The results showed a ratio between 7.50% to 9.28% of oil content in lupin seed. Unroasted (bitter and sweet) lupin oil contained a high level of oleic acid ω9 (42.65 and 50.87%), followed by linoleic acid ω6 (37.3 and 34.48%) and linolenic acid ω3 (3.35 and 6.58%), respectively. Concerning phytosterols, unroasted (bitter and sweet lupin) seed oil reflected high values (442.59 and 406.18 mg/100 g oil, respectively). Bitter lupin oil contains a high amount of phenolics, although a lower antioxidant potency compared to sweet lupin oil. This phenomenon could be connected with the synergistic effect between phenolics and carotenoids higher in sweet lupin oil. The results reflected a more efficiently bitter lupin oil against anti-toxigenic fungi than sweet lupin oil. The roasting process recorded enhances the antimicrobial activity of bitter and sweet lupin seed oil, which is linked to the increment in bioactive components during the roasting process. These results concluded that lupin oil deems a novel functional ingredient and a valuable dietary fat source. Moreover, lupin oil seemed to have antifungal properties, which recommended its utilization as a carrier for active-antifungal compounds in food products.

Heating effect on quality characteristics of mixed canola cooking oils

Background

The subcontinent is famous for its variety of seasonal foods cooked in vegetable seed cooking oils at elevated heating. Oils are often of poor quality that effect to consumer health. The work, therefore, planned to examine the effects of heat on the quality of mixed canola cooking oils (MCCOs). MCCOs were analyzed by preparing volatile fatty acid methyl esters (FAMEs) and for physiochemical properties.

Results

A major change was observed in the FAs composition of various MCCOs as coded K-1 to K-5. MCCOs were found rich in unsaturated 9-octadecanoic acid (oleic acid C_18:1) and 9, 12-octadecadienoic acid (linoleic acid C_18:2) along saturated octadecanoic acid (stearic acid C_18:0). Results reveals that canola oil samples are mixed in the range of 4–30% with other vegetable oils and animal fats. The quality of canola cooking oils further reduced after heating to 100 °C, 200 °C and 350 °C, respectively. Quality parameters of MCCOs were significantly altered after heating and found as color (510–520 nm to 570–600 nm), mass 220–237 g to 210–225 g, volume 250 mL to 239 mL, pH (6.76–6.89), specific gravity (0.87–0.92), refractive index (1.471–1.475), saponification value (SV) (0.7–2.5), un-saponifiable matter (2.4–9.8%) and acid value (AV) (1.20–5.0 mg KOH).

Conclusion

Heating of oils at elevated temperature have shown a significant effect on pH, specific gravity and un-saponifiable matter (p-value < 0.05). Large changes in the physicochemical parameters and FAs composition help to develop a conclusion that cooking at high temperatures affects the quality of mixed canola cooking oils.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13065-022-00796-z.

Influence of dry air and infrared pre-treatments on oxidative stability, Maillard reaction products and other chemical properties of linseed (Linum usitatissimum L.) oil

In this study, the influence of dry air and infrared pre-treatments on linseed oil (LO) yield, chemical properties, colour, pigment content, total phenolic content (TPC), Maillard reaction products (MRPs), fatty acid composition (FAC), radical scavenging activity (RSA), and oxidative stability index (OSI) were investigated. An increase in dry air and infrared roasting temperature had increased the LO yield, pigment content, a* value, TPC, RSA, OSI, and browning index (BI) while lowered the L* and b* values of LO. Higher OSI (2.24 h), chlorophylls (2.29 mg/kg), carotenoids (3.87 mg/kg), TPC (63.67 mg GAE/100 g), RSA (62.53%), BI (0.330), and MRPs (2.10 mg/kg) were detected in LO by dry air roasting at 180°C for 10 min. Dry air and infrared roasting had slightly affected the FAC of LO. Both dry air and infrared pre-treatments had influenced the LO quality characteristics. However, dry air roasting of linseed at 180°C for 10 min proved more effective in improving oxidative stability, antioxidant activity and other quality characteristics of LO.

SUPPLEMENTARY INFORMATION

The online version of this article at 10.1007/s13197-021-05023-6.

Neoteric approach for peanuts biofilm using the merits of Moringa extracts to control aflatoxin contamination

Aflatoxigenic fungi and aflatoxins are still a principal challenge that threatened peanut production, marketing, and handling. This study aimed to face the problem using bioactive materials, which reduce fungi and mycotoxin contamination, Moringa extracts may be suitable for solving this challenge. Also, the study was compared the extracts of leaves and oil-free seeds. Fresh leaves and seeds were collected, dried, and milled, while oil was collected by cold pressing. The extracts were evaluated for total phenols, flavonoids, and antioxidants, the oil contents of fatty acids, tocopherol, and sterols were determined. An emulsion for protecting peanuts compositing of leaves extract carried by Moringa oil, and commercial emulsifier. Leaves extract evaluation reflected distinct properties of its fibers, total phenols, and flavonoids. It was recorded a microbial inhibition of bacteria and fungi. The values ​​for both minimal inhibition and fungicidal concentrations were recorded at 3.2 mg/mL and 490 μg/L, respectively. For oil, it showed a unique content, as oleic acid was the main fatty acid, with an affinity between palmitic and behenic in their ratios. Also, oil was recorded by high contents of alpha-tocopherol and Δ7-Campesterol, with 1.166 mg/kg oil as total sterols content. The leaves extract has also a unique capacity to inhibit toxigenic fungi. By applying the composite emulsion for peanut coating, results expressed a high CFU-count inhibition when it was inoculated by A. flavus strain compared to the control.

HPLC phenolic profile and induction of apoptosis by Linum usitatissimum extract in LNCaP cells by caspase3 and Bax pathways

Linum usitatissimum is a candidate as a remedy to treat prostate problems in some folklore medicines. In this study, we have reported the phenolic and flavonoid constituents, antioxidant activity, and potential of the plant extract against prostate cancer cells. The phenolic and flavonoid compound profile of the extract were established using HPLC analysis. While the total phenolic and flavonoid content (TPC and TFC) were analyzed using classic methods. The antioxidant activity of the extract was also evaluated. MTT assay and flow cytometry technique was used to evaluate antiproliferation activity and induction apoptosis of the plant extract on prostate cancer cells of LNCaP. We also evaluated the gene expression of Bax and caspase-3 using the real-time qPCR assay. HPLC result revealed that L. usitatissimum extract (LUE) was rich in phenolic acids such as gallic, ferulic, and vanillic acid with the amount of 3.56, 2.12, 1.24 μg/g extract respectively. 383.4 mg GAE/g and 47.1 mgRuE/g were calculated for total phenolic and flavonoid content. LUE exhibited radical scavenging activity with IC50 = 19.3 ± 1.1 µg/mL. LUE chelated ferrous ions with IC50 = 121.1 ± 1.3 µg/mL. LUE showed anti-proliferative activity on LNCaP cells with the IC50 values of 8.3, 6.3, and 5.4 μg/mL after 24, 48, and 72 h treatment. LUE also increased cell mortality by inducing apoptosis (15.3-29.8%). The real-time qPCR results exhibited an increase in gene expression of Bax and caspase-3. Our in vitro study demonstrates that L. usitatissimum can be considered as an effective agent to inhibit the growth and invasion the human prostate cancer cells.

The Effect of Roasting on the Protein Profile and Antiradical Capacity of Flaxseed Meal

Roasting is more and more often used as a pre-treatment of flaxseeds. However, the process can influence flaxseed proteins that may be crucial for their properties. The aim of this research was to study changes in the electrophoretic protein profile (SDS-PAGE) and the antiradical capacity of flaxseed meals after roasting. The roasting temperature (160, 180, and 200 °C) and flaxseed cultivars (golden and brown seed) were factors including in the study. The free (F-MRP) and bound-to-protein (B-MRP) Maillard reaction products were also analyzed. The most significant changes in the SDS-PAGE protein profiles of roasted seeds of each of the tested flax cultivars were observed for the 13 kDa protein fraction (decrease) and for the 19 kDa and 17 kDa fractions (increase). The research revealed a significant correlation between the roasting temperature and B-MRP content, and changes in the percentage share of those three protein fractions. The antiradical capacity of roasted flaxseeds decreased, as compared with untreated seeds. After roasting at 200 °C the antiradical capacity of flaxseeds improved slightly, probably due to the MRP formation, but it was still significantly lower than that of the raw seeds. The research provides novel information about key protein fractions that seem to be important changing during heat treatment.

Physicochemical and fatty acid profile of egusi oil from supercritical carbon dioxide extraction

Oil extraction from egusi seeds using supercritical CO₂ extraction method was performed using series of operational parameters, temperature (55, 60, 75 °C), flow rate (30 g/h) and pressure (450, 600 bar). Egusi oil (EO) extracted at 60 °C, 30 g/h and 450 bar (EO1); 55 °C, 30 g/h and 600 bar (EO2) and 75 °C, 30 g/h and 600 bar (EO3) were investigated in a plant scale supercritical equipment. The fatty acid composition of egusi oil was analysed using gas chromatography, with result showing a high linoleic acid approximately (53%) and oleic acids (19%). The index of atherogenicity (IA%) and thrombogenicity index (IT %) were significantly low for the three oil samples, indicating its health benefits. Oxidative stability of egusi oil was analysed by Methrohm 743 Rancimat, confirming a less oxidised oil. Hence, egusi oil can be used as a raw material in dietary supplements and as a functional oil in the food industry.