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Nutritional Quality and Oxidative Stability during Thermal Processing of Cold-Pressed Oil Blends with 5:1 Ratio of ω6/ω3 Fatty Acids
Chemical characteristics and thermal oxidative stability of novel cold-pressed oil blends: GC, LF NMR, and DSC studies
Plant oils contain a high content of unsaturated fatty acids. Studies of food products have revealed a considerable disproportion in the ratio of ω6 to ω3. This article presents information on the healthful qualities of eight new oil blends that contain a beneficial proportion of ω6 to ω3 fatty acids (5:1), as well as their degradation during heating at 170 and 200 °C. The fatty acid profile was analyzed by gas chromatography (GC), content of polar compounds and polymers of triacylglycerols by liquid chromatography (LC), water content was measured by the Karl Fischer method, and oxidative stability was measured by differential scanning calorimetry (DSC) and low-field nuclear magnetic resonance (LF NMR) methods. The results showed that during heating, the polar fraction content increased in samples heated at both analyzed temperatures compared to unheated oils. This was mainly due to the polymerization of triacylglycerols forming dimers. In some samples that were heated, particularly those heated to 200 °C, trimers were detected, however, even with the changes that were observed, the polar fraction content of the blends did not go beyond the limit. Despite the high content of unsaturated fatty acids, the analyzed blends of oils are characterized by high oxidative stability, confirmed by thermoanalytical and nuclear magnetic resonance methods. The high nutritional value as well as the oxidative stability of the developed oil blends allow them to be used in the production of food, in particular products that ensure an adequate supply of ω3 fatty acids.
Improvement of Refined Rapeseed Oil Thermal Resistance by Native Antioxidants Present in Rapeseed, Coriander, and Apricot Cold-Pressed Oils
The research aimed to evaluate the effect of high monounsaturated cold-pressed oil addition on the inhibition of refined rapeseed oil degradation during heating at frying temperature. Cold-pressed rapeseed, coriander seed, and apricot kernel oils were added in amounts of 5 and 25%. Refined rapeseed oil without additives and refined rapeseed oil supplemented with tert-butylhydroquinone (TBHQ) were negative and positive control samples, respectively. Blends were heated in a thin layer at 170 and 200 °C. Considering the increase in total polar compounds (TPCs) and oxidized triacylglycerol monomer (oxTAG) content, natural additives demonstrated protective properties and were more effective than the TBHQ additive, especially at 200 °C. The lowest increases in TPC and oxTAG were found in AO5% at 170 °C (10.17% and 1.40 mg/g oil, respectively) and in AO25% at 200 °C (5.71% and 47.53 mg/g oil, respectively). The presence of triacylglycerol (TAG) dimers was found only in samples heated at 200 °C, and the lowest was in the sample with 25% coriander oil. It can be concluded that the addition of cold-pressed oils limited the TAG oxidation process. The addition of 25% coriander oil was effective in inhibiting the TAG polymerization process, and it may be a powerful alternative to synthetic antioxidants in improving stabilization of frying oils.
Analysis of Quality Distinctions of Pumpkin Seed Oil (Cucurbita pepo var. oleifera) and Walnut Oil (Juglans regia L.)
Fabrication and characterization of novel β-sitosterol-loaded O/W Pickering emulsions stabilized by edible insects protein/chitosan complex coacervates: Retention and stability evaluation
Physicochemical and Morphological Study of the Saccharomyces cerevisiae Cell-Based Microcapsules with Novel Cold-Pressed Oil Blends
Vegetable oils rich in polyunsaturated fatty acids are a valuable component of the human diet. Properly composed oil blends are characterized by a 5:1 ratio of ω6/ω3 fatty acids, which is favorable from a nutritional point of view. Unfortunately, their composition makes them difficult to use in food production, as they are susceptible to oxidation and are often characterized by a strong smell. Encapsulation in yeast cells is a possible solution to these problems. This paper is a report on the use of native and autolyzed yeast in the encapsulation of oils. The fatty acid profile, encapsulation efficiency, morphology of the capsules obtained, and thermal behavior were assessed. Fourier transform infrared analysis and low-field nuclear magnetic resonance relaxation time measurements were also performed. The process of yeast autolysis changed the structure of the yeast cell membranes and improved the loading capacity. Lower encapsulation yield was recorded for capsules made from native yeast; the autolysis process significantly increased the value of this parameter. It was observed that NY-based YBMCs are characterized by a high degree of aggregation, which may adversely affect their stability. The average size of the AY capsules for each of the three oil blends was two times smaller than the NY-based capsules. The encapsulation of oils in yeast cells, especially those subjected to the autolysis process, ensured better oxidative stability, as determined by DSC, compared to fresh blends of vegetable oils. From LF NMR analysis of the relaxation times, it was shown that the encapsulation process affects both spin-lattice T1 and spin-spin T2* relaxation times. The T1 time values of the YBMCs decreased relative to the yeast empty cells, and the T2* time was significantly extended. On the basis of the obtained results, it has been proven that highly unsaturated oils can be used as an ingredient in the preparation of functional food via protection through yeast cell encapsulation.
Changes in Oil Quality and Peroxidase Activity during Germination of Rape Seeds and Mustard Seeds
Vegetable oils are selected by consumers based on the presence of multiple bioactive substances, including polyunsaturated fatty acids, sterols, and tocopherols. Another important factor in oils is their quality. This research involved analyzing the oils quality and quantity of bioactive substances obtained from rape seeds and white mustard seeds that underwent germination. The quality of the oils was compared by determining the acid and peroxide values. Germination lowered the peroxide value by 86.3% and 71.4% for rapeseed oil and mustard oil, respectively. This was due to the germination step of the seed use oxygen, which was the substrate for lipid peroxidation. The activity of peroxidase increased by 95% for rapeseed oil and 94% for mustard oil during germination. An increase in the amount of polyunsaturated fatty acids in mustard oil also was noted during germination.
Storage of Rabbit Meat in Vacuum Extends the Oxidative Stability of Fat
ABSTRACTMeat quality is a very important factor for both food safety and consumer acceptance, and proper storage of meat can extend the time it stays fresh. This study thus looked at the effects of the atmosphere in which rabbit meat was stored on the oxidative stability of the meat and on its volatile compounds. Not only does the formation of oxidative products adversely affect the human body, but the compounds formed during oxidative changes also typically possess unpleasant aromas, leading to deterioration in the flavor of the meat. Our study analyzed three types of storage atmosphere for rabbit meat: vacuum (VAC), a modified atmosphere (LoOxMAP) composed of 60% CO2, 25% O2, and 15% N2, and an MAP (HiOxMAP) composed of 30% CO2 and 70% O2. The results show that the MAP with 70% oxygen (HiOxMAP) is the least beneficial variant of the three. Rabbit meat packed under HiOxMAP showed the greatest oxidative changes, and volatile compounds providing an unpleasant odor were detected. The fewest changes in meat stored for 21 days occurred in samples stored in VAC.Practical Applications: For the long‐term storage of rabbit meat at refrigerated temperature, it is best to use a vacuum atmosphere to slow down the oxidative changes in the meat fat.
Thermo-oxidative stability of asymmetric distigmasterol-modified acylglycerols as novel derivatives of plant sterols
The Effect of High-Temperature Heating on Amounts of Bioactive Compounds and Antiradical Properties of Refined Rapeseed Oil Blended with Rapeseed, Coriander and Apricot Cold-Pressed Oils
Cold-pressed oils are rich sources of bioactive substances, which may protect triacylglycerols from degradation during frying. Nevertheless, these substances may decompose under high temperature. This work considers the content of bioactive substances in blends and their changes during high-temperature heating. Blends of refined rapeseed oil with 5% or 25% in one of three cold-pressed oils (rapeseed, coriander and apricot) were heated at 170 or 200 °C in a thin layer on a pan. All non-heated blends and cold-pressed oils were tested for fatty acid profile, content and composition of phytosterols, tocochromanols, chlorophyll and radical scavenging activity (RSA) analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. Moreover, the stability of phytosterols, tocochromanols, DPPH and ABTS values was determined in heated blends. All tocochromanols were lost during the heating process, in particular, at 200 °C. However, there were some differences between homologues. α-Tocopherol and δ-tocopherol were the most thermolabile and the most stable, respectively. Phytosterols were characterized by very high stability at both temperatures. We observed relationships between ABTS and DPPH values and contents of total tocochromanols and α-tocopherol. The obtained results may be useful in designing a new type of fried food with improved health properties and it may be the basis for further research on this topic.
Sposób wytwarzania chleba mieszanego z leżakowanymi liśćmi morwy białej, w szczególności dla diabetyków
Black Cumin Essential Oil as an Active Stabilization Component of Rapeseed Oil During Deep-Fat Model Heating
The aim of this study was to evaluate the potential of black cumin essential oils to reduce the degradation of rapeseed oil during heating. Rapeseed oil was heated without addition and with the addition of black cumin essential oil (200 ppm, 500 ppm, and 1000 ppm), and with synthetic antioxidant TBHQ (200 ppm). The heating was carried out at 170 °C ± 10 °C for 6 h, in a deep-fat heating model. In all samples, changes in fatty acid profile, lipid-nutritional quality indices (PUFA/SFA ratio, atherogenicity index, thrombogenicity index, and hypocholesterolemic/hypercholesterolemic ratio), tocopherol and phytosterol content, total polar compound content, and triacylglycerol polymers were determined. The heating process led to oil degradation, which depended on the amount and type of additive used. The greatest changes were observed in the control sample (without additives). The addition of TBHQ or 200 ppm of black cumin essential oil reduced the adverse transformations to a similar level. Higher additions of black cumin essential oil led to a significant improvement in the quality of heated oils. The best results were obtained with the addition of 1000 ppm of black cumin essential oil.
Machine and Deep Learning in the Evaluation of Selected Qualitative Characteristics of Sweet Potatoes Obtained under Different Convective Drying Conditions
This paper discusses the use of various methods to distinguish between slices of sweet potato dried in different conditions. The drying conditions varied in terms of temperature, the values were: 60 °C, 70 °C, 80 °C, and 90 °C. Examination methods included instrumental texture analysis using a texturometer and digital texture analysis based on macroscopic images. Classification of acquired data involved the use of machine learning techniques using various types of artificial neural networks, such as convolutional neural networks (CNNs) and multi-layer perceptron (MLP). As a result, in the convective drying, changes in color darkening were found in products with the following temperature values: 60 °C (L = 83.41), 70 °C (L = 81.11), 80 °C (L = 79.02), and 90 °C (L = 75.53). The best-generated model achieved an overall classification efficiency of 77%. Sweet potato dried at 90 °C proved to be completely distinguishable from other classes, among which classification efficiency varied between 61–83% depending on the class. This means that image analysis using deep convolutional artificial neural networks is a valuable tool in the context of assessing the quality of convective-dried sweet potato slices.
Characterization of Selected Microalgae Species as Potential Sources of Nutrients and Antioxidants
Microalgae are exceptional organisms from a nutritional perspective, boasting an array of bioactive compounds that have long justified their incorporation into human diets. In this study, we explored the potential of five microalgae species: Nannochloropsis sp., Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira weissflogii, and Tisochrysis lutea. We conducted comprehensive analyses of their nutritional profiles, encompassing protein content, individual amino acid composition, mineral and trace element levels, fatty acid profiles (including saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs)), polyphenol compositions, and vitamin B content. The antioxidant activity of the ethanolic extracts was evaluated using two methods: ABTS and DPPH radical scavenging assay. The total protein content of the microalgae ranged from 34.09 ± 0.39% to 42.45 ± 0.18%, with the highest concentration observed in T. weissflogii. Essential amino acids such as histidine, threonine, lysine, valine, isoleucine, leucine, phenylalanine, and methionine were present in concentrations ranging from 0.53 ± 0.02 to 12.55 ± 2.21 g/16 g N. Glutamic acid emerged as the most abundant amino acid, with concentrations ranging from 6.73 ± 0.82 to 12.55 ± 2.21 g/16 g N. Among the microalgae species, T. chuii exhibited the highest concentrations of calcium (Ca) and manganese (Mn), while C. muelleri showed prominence in magnesium (Mg), sodium (Na), and iron (Fe). T. weissflogii stood out for its potassium (K) content, and T. lutea contained notable amounts of copper (Cu), zinc (Zn), and lead (Pb). Regarding fatty acid profiles, Nannochloropsis sp. and T. chuii were predominantly composed of SFA, while C. muelleri and T. weissflogii were rich in MUFA. PUFAs dominated the fatty acid profile of T. lutea, which also exhibited the most diverse range of polyphenolic substances. We also analyzed the B vitamin content, with T. lutea displaying the highest concentrations of niacin (B3) and riboflavin (B2). Antioxidant activity was confirmed for all microalgae tested using DPPH and ABTS radical IC50 (mg/mL) converted to Trolox equivalent (TEAC). These findings underscore the substantial potential of the examined microalgae species as sources of biologically valuable substances characterized by rapid growth and relatively undemanding cultivation conditions.
Quality of Oil Pressed from Hemp Seed Varieties: ‘Earlina 8FC’, ‘Secuieni Jubileu’ and ‘Finola’
In the last decade, the demand for edible niche oils has increased. Therefore, the aim of this study was to characterize the seeds hemp (Cannabis sativa L.) varieties: ‘Finola’ (FIN-314)’, ‘Earlina 8FC’, and ‘Secuieni Jubileu’, and cold and hot pressed oils were prepared from each seed. The seeds were examined for moisture content, granulometric distribution, bulk density, and fat content. Seeds were pressed without and with preconditioning (60 °C), and oil yield and pressing time were recorded. The oil was filtered through cellulose membranes. Oil–water content, oil color, fatty acid profile, and sterol content were studied. From the study conducted, there are significant differences in the parameters of oil recovery and its quality compared to ‘Finola’ seed oil, which is widely reported in the literature. ‘Finola’ oil yield was the lowest, with an average of 79% compared to ‘Earlina’ (82%) and ‘S. Jubileu’ (84%). All oil samples contained a comparable amount of sterols, with campesterol (0.32 mg/g), β-sitosterol (1.3 mg/g) and Δ5-avenasterol (0.15 mg/g) predominating. From the organoleptic evaluation, it was evident that both varieties hemp oils and marc (‘Earlina’ and ‘S. Jubileu’) were not bitter like the “Finola” oil and marc. More detailed studies in this direction have to be undertaken.
Changes in Resveratrol Containing Phytosterol Liposomes During Model Heating
Background: Phytosterols are bioactive lipids susceptible to oxidation, particularly under thermal stress. Incorporation into liposomes may enhance their stability, while resveratrol—a natural antioxidant—could further limit thermal degradation. Stigmasterol esters, which contain fatty acid residues prone to oxidation, require additional characterization to understand their behavior under heating. Methods: Liposomes composed of dipalmitoylphosphatidylcholine (DPPC) were enriched with free stigmasterol (ST), stigmasteryl myristate (ME), or stigmasteryl oleate (OE), with or without resveratrol (RES). Liposomal systems were characterized using transmission electron microscopy, zeta potential, and hydrodynamic diameter analyses. Samples were heated at 60 °C and 180 °C for 8 h to evaluate stigmasterol degradation, oxyphytosterol (SOP) formation, and decomposition of fatty acid residues in the esters. Results: Liposomes remained structurally stable at 60 °C but underwent marked alterations at 180 °C. ST formed the smallest particles, while ME and OE systems exhibited larger hydrodynamic diameters. Incorporation of resveratrol enhanced thermal and oxidative stability, reducing stigmasterol degradation (7.73–18.86% at 60 °C; 29.66–35.28% at 180 °C) and limiting SOP formation. Differences in the breakdown of myristic versus oleic acid residues highlighted the role of fatty acid type in determining thermal resistance. Conclusions: Resveratrol effectively improves the stability of liposomes containing stigmasterol or its esters and mitigates oxidative damage under thermal stress. Protective effects were particularly evident at moderate temperatures, indicating the potential of resveratrol–phytosterol liposomes as thermally stable delivery systems.
Characteristics of Langmuir monomolecular monolayers formed by the novel oil blends
Abstract The aim of this work was to assess the physical properties of Langmuir monolayers of three new oil blends “RBWg” (obtained by mixing rapeseed oil, black cumin oil, and wheat germ oil), “REp” (rapeseed oil and evening primrose oil), and “CRb” (camelina oil and rice bran oil), as well as to characterize the molecular dynamics of their protons using low-field nuclear magnetic resonance (LF NMR) method. The studied blends are rich in oleic acid (C18:1), linolenic acid (C18:2), and α-linolenic acid (18:3). The chromatographically determined ratio of n6 to n3 fatty acids was found to be in the range of 5.18–5.27. The appropriate n6/n3 fatty acid ratio was also confirmed by FT-IR analysis. The spin–lattice relaxation rate (R 1) and spin–spin relaxation time (R 2) measured by LF NMR method were similar for the RBWg and REp blends but different from the third oil blend (CRb), which indicates lower proton mobility in CRb. The observed changes in the properties of monolayers of oil blends suggest that the refined rice bran oil in the CRb blend also significantly changes the viscoelastic properties of this blend. The results obtained in this study provide a theoretical basis for the development of a well-balanced approach to using oils in food production technology.
Analysis of Changes in the Amount of Phytosterols after the Bleaching Process of Hemp Oils
Unrefined vegetable oils from niche oilseeds are now sought after by consumers because of their unique nutritional properties and taste qualities. The color and flavor intensity of niche oils is a big problem, and their refining is not industrially feasible due to the small production scale. The study undertaken aimed analyze the effect of changing the amount of phytosterols (PSs) after the bleaching process of hemp oils of the ‘Finola’, ‘Earlina 8FC’ and ‘Secuieni Jubileu’ varieties. Cold-pressed (C) and hot-pressed (H) crude vegetable oils were bleached with selected bleaching earth (BE) at two concentrations. The post-process BE was extracted with methanol. The amount of PSs in the crude oils and the extract after washing the BE with methanol was analyzed by GC (gas chromatography). The study shows that the bleaching process did not significantly affect the depletion of PSs in the oils. Trace amounts of PSs remain on the BE and, due to methanol extraction, can be extracted from the oil. The conclusion of the performed research is that the bleaching of hemp oil does not cause depletion of the oil, and it significantly improves organoleptic properties. The oil bleaching process results in an oil loss of less than 2% by weight of the bleached oil, while the loss depends on the type of BE used. The study shows that the loss of phytosterols after the bleaching process averages 2.69 ± 0.69%, and depends on the type of BE used and the oil extracted from different varieties of hemp seeds.
The Influence of the Adsorbents Used on Changes in the Quality Parameters of Pumpkin Seed Oil as a Result of a Single-Stage Refining Process
This study aimed to evaluate the impact of low- and high-temperature bleaching processes on the quality parameters of pumpkin seed oil. The research focused on optimizing the process to improve the oil’s physicochemical properties while reducing losses of valuable bioactive components. The bleaching process was carried out using 12 adsorbents in four technological variants, differing in temperature and adsorbent amount (30 °C/2% w/w, 30 °C/5%, 90 °C/2%, and 90 °C/5%). The scope of the analyses included, among others, the determination of acid (AV), peroxide (POV), and anisidine values (AnV), as well as the characterization of the fatty acid profile and the content of phytosterols and tocopherols. The data obtained were subjected to principal component analysis (PCA) to correlate the type of adsorbent with the process effects. It was shown that bleaching partially improves the oil’s quality parameters, though it is associated with a reduction in tocopherol and carotenoid content. Aluminum oxides are very poor adsorbents of vegetable oil components. Finely divided activated carbons exhibit the broadest spectrum of adsorbed components. Furthermore, bleaching earths have different effects on oil components depending on their composition and process temperature.
