Effects of processing methods on the chemical composition and antioxidant capacity of walnut (Juglans regia L.) oil

Chemical compositions and oxidative stabilities of cold-pressed walnut oils (Juglans regia L.): Effects of chemical refining, water degumming, and molecular distillation

Walnut oils are of important academic and economic value, and are becoming one of the most important woody oils. Accurate and moderate refining techniques are required to produce high-quality walnut oils. In this work, walnut oils obtained from cold processing were refined in three typical techniques, mainly chemical refining, water degumming, and molecular distillation. Physicochemical properties (acid value and peroxide value [POV]), minor components (tocopherol, polyphenols, and phytosterol), oxidative stability indices, and volatile compounds were analyzed to find out the appropriate refining method for the cold-pressed walnut oils. Quality indices of all the refined oils from the three different refining methods met the requirements of the national standard, of which the POV of chemically refined oil (0.241 g/100 g) was higher than crude oil (0.058 g/100 g). Water degumming was most suitable for retaining of bioactive compounds, for example, the tocopherol was 259.40 mg/kg, the polyphenols was 44.54 mg GAE/kg, and the phytosterol was 987.32 mg/kg, but oxidation stability of the obtained oil (3.09 h) was lower than that of molecular distilled oil (4.18 h). Initial physicochemical properties especially the POV had a significant impact on oxidation stability. There is a trade-off between the retention of nutrients and extending shelf life, indicating appropriate refining techniques should be developed; that is, water degumming is suggested to be involved in producing high-quality cold-pressed walnut oils.

Utilization of low-grade walnut kernels for oil extraction using eco-friendly methods: a comparative analysis of oil composition, antioxidant and antimicrobial activity

Walnut oil was extracted using three different eco-friendly extraction methods, solvent extraction (using ethyl acetate [EA] and ethanol [ET]), aqueous enzymatic extraction (AEE), and ultrasound-assisted enzymatic extraction (UAEE), and their lipid yield, lipid composition, physicochemical analysis, mineral composition, total phenols, antioxidant capacity, and antimicrobial activity were analyzed and compared. The AEE technique offered a greater yield (50.6%) than the other extraction methods and gave comparatively higher linoleic acid (66.12%) content. Palmitic, oleic, linoleic, linolenic, and stearic acids were the principal components that GC/MS detected in all the oil samples. UAEE produced the most polyphenols (0.49 mgGAE/g), followed by AEE (0.46 mgGAE/g), EA (0.45 mgGAE/g), and ET (0.35 mgGAE/g). The DPPH assay results were in the order of UAEE (191 μmolTE/kg) > AEE (186 μmolTE/kg) > EA (153 μmolTE/kg) > ET (130 μmolTE/kg). The FRAP assay findings showed a similar pattern: UAEE (112 molTE/kg) > AEE (102 molTE/kg) > EA (96 molTE/kg) > ET (82 molTE/kg). Results suggested that for a higher extraction yield, AEE is the better technique and UAEE is the recommended method for enhancing walnut oil antioxidant capacity. Additionally, it was found that polyphenols considerably increased the antioxidant capacity of walnut oil and are thought to be health-promoting. The results demonstrated the antibacterial effectiveness of the extracted oil against Bacillus subtilis, Bacillus licheniformis, and Staphylococcus aureus. This study provides information about low-cost and ecofriendly technologies of walnut oil extraction for food, cosmetic, and medical uses.

A comprehensive foodomics analysis of rambutan seed oils: Focusing on the physicochemical parameters, lipid concomitants and lipid profiles

A foodomics approach was employed to systematically characterize and compare the quality parameters, antioxidant activity, minor-components, fatty acid composition, and lipid profiles of the seed oils from the three most popular rambutan varieties in China. The total lipid content ranged from 23.40 to 25.77 g/100 g. The fatty acids 9cC18:1 (39.84%-40.92%) and C20:0 (28.45%-30.23%) were identified as the dominant ones, which are uncommon among higher plants. All oil samples exhibited low AI and TI values. BR-7 exhibited the highest levels of squalene (21.48 mg/kg), cholesterol (144.43 mg/kg), and tocopherol (17.42 mg/kg), and the lowest levels of polyphenols (24.21 mg GAE/kg). Additionally, a total of 807 lipid species were identified, with TAG, DGTS, and PE being the predominant ones. Multivariate statistical analyses revealed significant variations in lipid profiles among the varieties, particularly in glycerophospholipids and sphingolipids. Fifty-seven distinct lipids were identified as potential markers for distinguishing between rambutan varieties. Furthermore, a hypothetical scenario was developed by linking relevant lipid metabolism pathways. These findings establish a theoretical framework for comprehending rambutan seed oil in depth and unlocking its high-value potential.

Optimization of Production Parameters for Fabrication of Gum Arabic/Whey Protein-Based Walnut Oil Loaded Nanoparticles and Their Characterization

The encapsulation of fatty acids, including walnut oil, within complexes is a promising strategy to address challenges, for instance, low water solubility and susceptibility to oxidation while incorporating these oils into food products. Additionally, encapsulation can effectively mask undesirable odor and flavor. The current study focuses on the optimization of walnut oil nanoparticles (WON) using complexes fabricated from gum arabic and whey protein by applying a response surface methodology. The impact of three different independent variables were determined, such as surfactant mixture (33-66%), walnut oil (5-25%), and sonication time (60-300 s), under three distinct desired conditions (low, medium, and high) on four different responses, i.e., particle size, polydispersity index (PDI), moisture level, and encapsulation efficiency (EE). The findings of the present study indicate that the point prediction-based WON resulted in significantly low particle size (82.94 nm), PDI (0.19), moisture content (3.49%), and high EE (77.26%). Fourier transform infrared spectroscopy (FTIR) study demonstrated the successful encapsulation of walnut oil and wall material into nanocapsules. Differential scanning calorimetry (DSC) verified the improved thermal stability property of WON after incorporation, and scanning electron microscopy (SEM) indicated that the WON had relatively fragile and smooth surfaces, along with the presence of few porous structures. The recorded experimental data from the existing study showed that the developed formulation of WON was potentially useful as a value-added ingredient for food industries.

Exploration of markers in oxidized rancidity walnut kernels based on lipidomics and volatolomics

Walnut kernels are prone to oxidation and rancidity due to their rich lipid composition, but the existing evaluation indicators are not sensitive enough to promote their industrial development. This study aims to investigate the potential markers in oxidative rancidity walnut kernels using lipidomics and volatolomics. The results showed that the antioxidant capacity of walnut kernels significantly decreased after oxidation, with the decreasing of total phenolic content from 36276.34 mg GAE/kg to 31281.53 mg GAE/kg, the DPPH and ABTS free radical scavenging activity from 89.25% to 73.54%, and 61.69% to 43.73%, respectively. The activities of lipoxygenase (LOX) and lipase (LPS) increased by 6.08-fold and 0.33-fold, respectively. By combining volatolomics and chemometrics methods, it was found that significant differences existed in the content of hexanal, caproic acid, 1-pentanol, (E)-2-octenal, and 2-heptanenal before and after walnut kernel oxidation (VIP > 1). Based on the results of lipidomics, it can be concluded that the above five compounds can serve as characteristic markers for walnut kernel oxidative rancidity, mainly produced through glycerol phospholipid (GPL), glyceride, linoleic acid (LA), and α-linolenic acid (ALA) metabolism pathways. Possible mechanisms of lipid degradation in oxidized walnut kernels were also proposed, providing technical support for the storage, preservation, and high-value utilization of walnut kernels.

Walnut (Juglans regia L.) kernel oil bodies recovered by aqueous extraction for utilization as ingredient in food emulsions: Exploration of their microstructure, composition and the effects of homogenization, pH, and salt ions on their physical stability

Natural oil-in-water emulsions containing plant oil bodies (OBs), also called oleosomes, rich in health-promoting omega-3 polyunsaturated fatty acids (ω3 PUFA) are of increasing interest for food applications. In this study, we focused on walnut kernel OBs (WK-OBs) and explored their microstructure, composition and physical stability in ionic environments as well as the impact of homogenization. A green process involving aqueous extraction by grinding of WK allowed the co-extraction of OBs and proteins, and centrifugation was used to recover the WK-OBs. Confocal laser scanning microscopy images showed the spherical shape of WK-OBs with an oil core envelopped by a layer of phospholipids (0.16 % of lipids) and embedded proteins. Their mean diameter was 5.1 ± 0.3 µm. The WK-OBs contained 70.1 % PUFA with 57.8 % ω6 linoleic acid and 12.3 % ω3 α-linolenic acid representing 68 % and 11.6 % of the total fatty acids in the sn-2 position of the triacylglycerols (TAG), respectively. Trilinolein was the main TAG (23.1 %). The WK-OBs also contained sterols (1223 ± 33 mg/kg lipids; 86 % β-sitosterol), carotenoids (0.62 ± 0.01 mg/kg lipids; 49.2 % β-carotene), and tocopherols (322.7 ± 7.7 mg/kg lipids; 89 % γ-tocopherol), confirming their interest as health-promoting ingredients. The decrease in the size of WK-OBs under high-pressure homogenization avoided phase separation upon storage. The anionic WK-OB surface at neutral pH was affected by stressful ionic environments (pH, NaCl, CaCl2), that induced aggregation of WK-OBs and decreased the physical stability of the emulsions. Emulsions containing WK-OBs are promising to diversify the market of the ω3-rich plant-based food products and beverages.

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.

Influence of different cooking methods on quality characteristics and nutritional value of gluten-free beef burger patties formulated with walnut oil, safflower oil and buckwheat

In this study, it was aimed to develop gluten-free beef burger patties with walnut and safflower oils and to examine the effects of different cooking methods on the quality and nutritional value of the product. Two different cooking methods (oven and pan cooking) and 60 days of storage were applied to the patties that were produced by replacing 50% animal fat content with walnut and safflower oils and using buckwheat flour instead of rusk. The highest MUFA+PUFA and MUFA+PUFA/SFA values were determined in walnut oil added oven cooked samples at the beginning of the storage and safflower oil added oven cooked samples at the end of the storage (P < 0.05). The nutritional quality indexes (NVI, HH, AI, HPI) of fat of beef burger patties improved with the replacement of fat with safflower and walnut oil and preserved better with the oven-cooked method according to the pan cooking method. The addition of walnut oil significantly increased the vitamin E values compared to those of the control sample and these values were preserved during storage (P < 0.05). However, the flavor and overall acceptability scores of the safflower oil samples were higher than those of the walnut oil samples during 30 days of storage (P < 0.05). It was concluded that safflower-added samples could be preferred in terms of lower hardness, oxidation value, total saturated fatty acid, higher cooking yield and sensory evaluation scores.

Effect of Extraction Methods on the Physicochemical Properties, Chemical Composition, and Antioxidant Activities of Samara Oil

Samara oil (Elaeagnus mollis Diels kernel oil) exhibits diverse healthy functions; however, the effect of extraction on its quality is still unclear. The present study was undertaken to evaluate the effect of extraction methods (solvent extraction: ethyl acetate, acetone, n-hexane, and petroleum ether; mechanical extraction: hot-pressing and cold-pressing) on the color, acid value, peroxide value, fatty acid composition, bioactive compounds, antioxidant activities, and oxidative stability index of samara oil obtained from Elaeagnus mollis Diels kernels. The results indicated that extraction methods affected the physicochemical properties, chemical composition, and antioxidant activities of samara oil except for fatty acid composition and γ-tocopherol. The highest values of bioactive compounds including polyphenols (140.27 mg gallic acid equivalent (GAE)/kg) and carotenoids (42.95 mg/kg) were found in samara oil extracted with acetone. The values of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assays, as well as oxidative stability index (OSI), were the highest in this oil. Correlation analysis results demonstrated that DPPH, ABTS, and OSI of samara oil were positively correlated with polyphenols and carotenoids. After evaluation, acetone could be used to extract samara oil. The study provides new information on the samara oil process.

Bioactives from Crude Rice Bran Oils Extracted Using Green Technology

Crude rice bran oils from different rice cultivars and extraction methods bear different contents of nutraceuticals. The health benefits of lowering cholesterol activity of rice bran oil being confirmed by many reports are partly attributed to non-nutrient nutraceuticals, especially γ-oryzanol, phytosterols, and policosanols. As the world has been facing the global warming crisis, green extraction technology is gaining attention from many sectors. The current study aims to compare the nutraceutical composition with respect to γ-oryzanol, phytosterol, and policosanol content as well as the antioxidant properties of crude rice bran oils extracted from white and red rice bran using three green technologies, comparing with conventional hexane extraction. The data show that the traditional solvent extraction gave the highest oil yield percentage (26%), but it was not significantly different from subcritical liquefied dimethyl ether extraction (24.6%). Subcritical liquefied dimethyl ether extraction gave higher oil yield than supercritical CO2 extraction (15.5–16.2%). The crude rice bran oil extracted using subcritical liquefied dimethyl ether extraction produced the highest total phenolic contents and antioxidant activities. The highest γ-oryzanol content of the crude rice bran oil was found in oil extracted by conventional cold press (1370.43 mg/100 g). The γ-oryzanol content of the oil obtained via subcritical liquefied dimethyl ether extraction was high (1213.64 mg/100 g) compared with supercritical CO2 extraction. The red rice bran yielded the crude rice bran oil with the highest total phytosterol content compared with the white bran, and the oil from red rice bran extracted with subcritical liquefied dimethyl ether generated the highest total phytosterol content (1784.17 mg/100 g). The highest policosanol content (274.40 mg/100 g) was also found in oil obtained via subcritical liquefied dimethyl ether extraction.

Roasting treatments affect oil extraction rate, fatty acids, oxidative stability, antioxidant activity, and flavor of walnut oil

Introduction

The quality of pressed walnut oil can be improved by moderate roasting treatment.

Methods

This study compared physicochemical characteristics and antioxidant ability of walnut oils pressed from differently roasted pretreated walnuts, analyzed the correlation among these indicators by using Pearson correlation coefficient and correlation coefficient heatmap, and evaluated the volatile organic compounds (VOCs) of walnut oil under optimal pretreatment roasting conditions using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS).

Results

Hierarchical cluster analysis (HCA) and principal component analysis (PCA) were able to remarkably distinguish walnut oil produced by different roasting processes. In addition, correlation analysis showed that there was a significant impact among indicators. There were 73 VOCs were identified in the optimum roasted treated walnut oil, consisting of 30 aldehydes, 13 alcohols, 11 ketones, 10 esters, 5 acids, 2 oxygen-containing heterocycles, 1 nitrogen-containing heterocycle and 1 other compound. GC-IMS results showed that aldehydes contributed significantly to the volatile flavor profile of walnut oil, especially (E)-2-heptenal, (E)-2-pentenal and hexenal.

Discussion

The properties of walnut oil based on varying roasting pretreatment of walnut kernels were significantly differentiated. Roasting at 120°C for 20 min is a suitable pretreatment roasting condition for pressing walnut oil. Roasting at 120°C for 20 min is a suitable pretreatment roasting condition for pressing walnut oil.

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.

Walnut Oil Oleogels as Milk Fat Replacing System for Commercially Available Chocolate Butter

A breakfast spread named chocolate butter exists on the market. For economic and technological reasons, cream in the original recipe is replaced with vegetable oils such as palm oil or by partially hydrogenated sunflower oil. The study aims to reformulate chocolate flavor butter, using cold pressed walnut oil (WO) oleogels (OGs) structured with 10% waxes and monoglyceride (MG), as a milk fat replacing system. The rheological, textural and microscopic characteristics of the oleogels and the spreads were compared. Oil binding capacity (OBC) and colorimetry were also assessed. Fourier transform infrared studies were used to monitor the composition of the samples. Oleogels and oleogel based chocolate butter behaved like strong gels (G’ > G”). The use of candelilla wax (CW) led to the formation of a much firmer spread (S-CW), with a hardness of 3521 g and G’LVR of 139,920 Pa, while the monoglyceride-based spread (S-MG) registered a hardness of 1136 g and G’LVR 89,952 Pa. In the spreadability test, S-CW registered a hardness of 3376 g and hardness work of 113 mJ, comparable to the commercially available chocolate butter. The formulated spreads exhibited shear thinning effects, and increased viscosity with decreasing temperature. A large round peak at 3340 cm−1 was present in the spectra of the candelilla wax-based oleogel (OG-CW) and the reference spreads due to hydrogen bonding, but was absent in S-CW or S-MG. The FTIR spectra of the alternative spreads exhibited the same peaks as the WO and the oleogels, but with differences in the intensities. S-CW exhibited a dense crystal network, with spherulitic crystals of 0.66−1.73 µm, which were statistically similar to those of the reference made from cream (S-cream). S-MG exhibited the lowest stability upon centrifugation, with an OBC of 99.76%. Overall, both oleogel-based chocolate spreads can mimic the properties of the commercially existing chocolate butter references.

Comparison of chemical characterization and oxidative stability of Lycium barbarum seed oils: A comprehensive study based on processing methods

Five different processing methods (cold pressing, hot pressing, solvent extraction, ultrasound-assisted solvent extraction, and supercritical fluid extraction) were evaluated to extract oils from Lycium barbarum (L. barbarum) seeds based on the lipid composition, minor bioactive components, and oxidative stability of oils. A large proportion of unsaturated fatty acids was detected in the L. barbarum seed oil, especially linoleic acid (65.24-66.26%). Minor bioactive components were abundant in L. barbarum seed oils, including tocopherols (292.65-488.49 mg/kg), phytosterols (9606.31-166,684.77 mg/kg), polyphenols (35.65-113.87 mg/kg), and carotenoid (4.17-46.16 mg/100 g). Specifically, the phytosterol content was higher than that of other common oils. Comparing the different processing techniques, ultrasound-assisted solvent extraction provided the highest extraction yield and recovery. The quantities of tocopherols, phenols, and phytosterols in hot-pressed oil were higher than those in oils extracted from other methods, and thus it had the best oxidative stability. L. barbarum seed oils extracted by different techniques showed various characteristics and could be distinguished through principal component analysis and hierarchical cluster analysis. PRACTICAL APPLICATION: L. barbarum seed oil is a potentially underutilized oil resource with abundant essential fatty acid and phytosterol, which owns great value to apply in the nutritional, cosmetic, and medicinal fields. Hot pressing is an efficient method to produce L. barbarum seed oil for health care with high nutritional value and good quality, which can also be easily implemented on an industrial scale.

Comparison of Different Extraction Processes on the Physicochemical Properties, Nutritional Components and Antioxidant Ability of Xanthoceras sorbifolia Bunge Kernel Oil

In this study, we investigated and compared the oil yield, physicochemical properties, fatty acid composition, nutrient content, and antioxidant ability of Xanthoceras sorbifolia Bunge (X. sorbifolia) kernel oils obtained by cold-pressing (CP), hexane extraction (HE), aqueous enzymatic extraction (AEE), and supercritical fluid extraction (SFE). The results indicated that X. sorbifolia oil contained a high percentage of monounsaturated fatty acids (49.31–50.38%), especially oleic acid (30.73–30.98%) and nervonic acid (2.73–3.09%) and that the extraction methods had little effect on the composition and content of fatty acids. X. sorbifolia oil is an excellent source of nervonic acid. Additionally, the HE method resulted in the highest oil yield (98.04%), oxidation stability index (9.20 h), tocopherol content (530.15 mg/kg) and sterol content (2104.07 mg/kg). The DPPH scavenging activity rates of the oil produced by SFE was the highest. Considering the health and nutritional value of oils, HE is a promising method for X. sorbifolia oil processing. According to multiple linear regression analysis, the antioxidant capacity of the oil was negatively correlated with sterol and stearic acid content and positively correlated with linoleic acid, arachidic acid and polyunsaturated fatty acid content. This information is important for improving the nutritional value and industrial production of X. sorbifolia.

Characteristics and Antioxidant Activity of Walnut Oil Using Various Pretreatment and Processing Technologies

This study was the first time the effects of pretreatment technology (microwave roasting, MR; oven roasting, OR; steaming roasting, SR) and processing technology (screw pressing, SP; aqueous enzymatic extraction, AEE; subcritical butane extraction, SBE) on the quality (physicochemical properties, phytochemical content, and antioxidant ability) of walnut oil were systematically compared. The results showed that the roasting pretreatment would reduce the lipid yield of walnut oil and SBE (59.53−61.19%) was the processing method with the highest yield. SR-AEE oil provided higher acid value (2.49 mg/g) and peroxide value (4.16 mmol/kg), while MR-SP oil had the highest content of polyunsaturated fatty acid (73.69%), total tocopherol (419.85 mg/kg) and total phenolic compounds (TPC, 13.12 mg/kg). The DPPH-polar and ABTS free radicals’ scavenging abilities were accorded with SBE > AEE > SP. SBE is the recommended process for improving the extraction yield and antioxidant ability of walnut oil. Hierarchical cluster analysis showed that processing technology had a greater impact on walnut oil than pretreatment technology. In addition, multiple linear regression revealed C18:0, δ-tocopherol and TPC had positive effects on the antioxidant ability of walnut oil, while C18:1n-9, C18:3n-3 and γ-tocopherol were negatively correlated with antioxidant activity. Thus, this a promising implication for walnut oil production.

Effects of Geographic Region and Cultivar on Fatty Acid Profile and Thermal Stability of Zanthoxylum bungeanum Seed Oil

Fatty acid profile and thermal stability of 7 varieties zanthoxylum bungeanum (GZF, GDJ, CJJ, SHY, SMN, SJY, GTS) seed oils (ZBO) were studied. Fatty acid profile, thermal stability were determined using gas chromatography equipped with flame ionization detector (GC-FID) and thermogravimetry analysis (TGA), respectively. Chemical properties, total phenolics and antioxidant activities of ZBO were determined as well. Palmitoleic acid and oleic acid (OA) were the dominant fatty acids, the ratio of ω-6/ω-3 polyunsaturated fatty acids (PUFA) of ZBO ranged from 0.66 ± 0.01 to 1.17 ± 0.01, seven varieties ZBO showed a higher thermal stability, with the 50% mass loss temperature ranged from 397.35 ± 4.02°C to 412.50 ± 2.35°C, GZF seed oil showed a balance fatty acid profile, the ratio of ω-6/ω-3 PUFA was 0.90 ± 0.01, GDJ seed oil showed a higher thermal stability, which the 50% mass loss temperature was 412.50 ± 2.35°C. These results suggested that fatty acid profile and thermal stability of ZBO were affected by cultivars and geographic region, and it may serve as a functional dietary oil.

An Efficient Deacidification Process for Safflower Seed Oil with High Nutritional Property through Optimized Ultrasonic-Assisted Technology

Safflower seed oil (SSO) is considered to be an excellent edible oil since it contains abundant essential unsaturated fatty acids and lipid concomitants. However, the traditional alkali-refined deacidification process of SSO results in a serious loss of bioactive components of the oil and also yields massive amounts of wastewater. In this study, SSO was first extracted by ultrasonic-assisted ethanol extraction (UAEE), and the extraction process was optimized using random centroid optimization. By exploring the effects of ethanol concentration, solid−liquid ratio, ultrasonic time, and the number of deacidification times, the optimum conditions for the deacidification of safflower seed oil were obtained as follows: ethanol concentration 100%, solid−liquid ratio 1:4, ultrasonic time 29 min, and number of deacidification cycles (×2). The deacidification rate was 97.13% ± 0.70%, better than alkali-refining (72.16% ± 0.13%). The values of acid, peroxide, anisidine and total oxidation of UAEE-deacidified SSO were significantly lower than those of alkali-deacidified SSO (p < 0.05). The contents of the main lipid concomitants such as tocopherols, polyphenols, and phytosterols in UAEE-decidified SSO were significantly higher than those of the latter (p < 0.05). For instance, the DPPH radical scavenging capacity of UAEE-processed SSO was significantly higher than that of alkali refining (p < 0.05). The Pearson bivariate correlation analysis before and after the deacidification process demonstrated that the three main lipid concomitants in SSO were negatively correlated with the index of peroxide, anisidine, and total oxidation values. The purpose of this study was to provide an alternative method for the deacidification of SSO that can effectively remove free fatty acids while maintaining the nutritional characteristics, physicochemical properties, and antioxidant capacity of SSO.

Chemical Composition, Nutritive Value, Volatile Profiles and Antioxidant Activity of Coconut (Cocos nucifera L.) Haustorium with Different Transverse Diameter

In order to promote the development and utilization of coconut haustorium (CH). The basic chemical composition, volatile profiles and antioxidant activities of three haustoria with different transverse diameters were investigated. Results showed large coconut haustorium (LCH) contained more soluble sugar (47.10%) and reducing sugar (17.68%), while small coconut haustorium (SCH) possessed more ash (10.17%), protein (9.22%) and fat (5.03%). All CH were rich in potassium (4.06–4.69%) and phosphorus (0.39–0.50%). The fatty acid composition of SCH and amino acid composition of middle coconut haustorium (MCH) was more reasonable, which indicated its relatively higher nutritive value. Acids ranging from 26.90% to 60.82% were the dominant volatile components in CH, especially isobutyric acid whose relative content in SCH was up to 56.78%. The haustorium extract with polysaccharide as the main component has certain antioxidant activities, the half eliminating concentration (EC₅₀ values) of LCH on hydroxyl radical and SCH on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical were 8.33, 1.18 and 2.44 mg/mL, respectively. These results provided a reference for the development and utilization of different CH as a raw material in functional food or dietary additives.

Effect of water content on the physical properties and structure of walnut oleogels

This study aimed to investigate the effect of water content on the properties and structure of oleogels by developing walnut oleogel based on potato starch and candelilla wax (CW). Physical, thermal, rheological and microstructure characteristics of the walnut oleogel were determined by texture analyzer, differential scanning calorimeter, rotary rheometer, X-ray diffractometer and optical microscope. Results showed that with increased water content, the hardness of the oleogel increased from 123.35 g to 158 g, whereas the oil loss rate decreased from 24.64% to 10.91%. However, these two values decreased slightly when the ratio of oil to water was 1 : 1. The prepared oleogels have a high elastic modulus, and the flow behavior of all walnut oleogels conformed to that of a non-flowing fluid. Microstructure observation indicated that the crystal size and quantity increased with an increase in water content, and the liquid oil was wrapped in the crystal network by CW and potato starch, forming solidified droplets to further promote gelation. In conclusion, when the ratio of oil to water is 39%, the oleogel has good physical properties and stable crystal structure. These findings can provide an indication of water content in the composition of oleogels.

Characterization of a novel squalene-rich oil: Pachira macrocarpa seed oil

Pachira macrocarpa is a woody oil crop with high economic and ornamental value. Although P. macrocarpa seeds are rich in oil, little information has been reported about its characterization. In this study, the fatty acids, minor components (tocopherols, squalene, phytosterols, and total phenols), antioxidant activity, cytotoxicity, thermal, and rheological behavior of the P. macrocarpa seed oil (PSO) were investigated for the first time. The results showed that the seeds contained 43.34% lipid, which was mainly composed of palmitic acid (49.96%), linoleic acid (31.22%), and oleic acid (13.48%). The contents of tocopherols, squalene, phytosterols, and total phenols in PSO were 42.01 mg/100 g, 96.78 mg/100 g, 119.67 mg/100 g, and 3.79 mg GAE/100 g, respectively. PSO showed relatively strong DPPH radical scavenging capacity (93.47 µmol TE/100 g) and high melting point (20.8°C). In addition, the oil exhibited Newtonian flow behavior and was not toxic to normal L929 cells at concentrations of 500-8000 µg/ml. As a whole, PSO may be considered as a valuable source for new multipurpose products for industrial utilization. PRACTICAL APPLICATION: Pachira macrocarpa is a woody oil crop and its seeds are rich in oil. Our study has investigated the physicochemical properties and chemical composition of the P. macrocarpa seed oil (PSO). The present study revealed PSO had potential as an edible oil, and it may be considered as a valuable source for new multipurpose products for food industrial utilization.

Impact of Hydro-Alcoholic Solvents on the Oil and Phenolics Extraction from Walnut (Juglans regia L.) Press-Cake and the Self-Emulsification of Extracts

The objective was to evaluate the performance of four hydro-alcoholic solvents to simultaneously extract oil and more polar molecules as phenolics, among others, to produce complex extracts that eventually could self-emulsify after solvent removal. Walnut press-cake was selected as the sourcing material. Extractions were performed as a semi-continuous operation up to a solvent-to-solid ratio of 28, with a fractional collection of the effluent. Among the solvents, labelled by their alcohol content EtOH 58, EtOH 86, iPro 60 and iPro 90 for ethanol (EtOH) and isopropanol (iPro), iPro 90 allowed to reach an oil extraction efficiency of 97% while the recovery for the other solvents was in the range of 30–40%. For both alcohols, the increase of the solvent hydration negatively influenced the oil extraction but positively increased the recovery of phenolics that reached 17.6 mg GAE/g_cake when EtOH 58 was used. Several fractions contained enough surface-active material and oil to self-assemble as emulsions. IPro 90 and EtOH 86 showed better performances in the sense that most extracts were able to emulsify, though extraction kinetics pointed out differences. The most hydrated solvents behaved equally, with extraction yields in the same range and a similar but limited emulsifying capacity of only few fractions.

Comparative Study of Chemical Compositions and Antioxidant Capacities of Oils Obtained from 15 Macadamia (Macadamia integrifolia) Cultivars in China

The planting area of macadamia in China accounted for more than one third of the world's planted area. The lipid compositions, minor components, and antioxidant capacities of fifteen varieties of macadamia oil (MO) in China were comparatively investigated. All varieties of MO were rich in monounsaturated fatty acids, mainly including oleic acid (61.74-66.47%) and palmitoleic acid (13.22-17.63%). The main triacylglycerols of MO were first time reported, including 19.2-26.1% of triolein, 16.4-18.2% of 1-palmitoyl-2,3-dioleoyl-glycerol, and 11.9-13.7% of 1-palmitoleoyl-2-oleoyl-3-stearoyl-glycerol, etc. The polyphenol, α-tocotrienol and squalene content varied among the cultivars, while Fuji (791) contained the highest polyphenols and squalene content. Multiple linear regression analysis indicated the polyphenols and squalene content positively correlated with the antioxidant capacity. This study can provide a crucial directive for the breeding of macadamia and offer an insight into industrial application of MO in China.