Evaluation of deodorization techniques using cyclodextrins on the headspace volatiles and antioxidant properties of onion.

Sulphur-containing volatiles in onion produce unpleasant odors and this limit their usage in foods. To expand its application, several additives including α-cyclodextrin (α-CD), ß-cyclodextrin (ß-CD), 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD), and chitosan were added to onion solution and evaluated for their effect on sulphur-containing volatiles. Also, antioxidant property using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and oxidative stabilities in an oil-in-water (O/W) emulsion were carried out. The total volatile contents were decreased in the order of α-CD (50.1%), ß-CD (49.3%), HP-ß-CD (46.2%), and chitosan (7%). Meanwhile, HP-ß-CD showed the highest DPPH radical scavenging ability followed by ß-CD, α-CD, and chitosan with decreasing order. The ß-CD significantly enhanced the oxidative stability of the O/W emulsion, whereas α-CD and ß-HP-CD showed prooxidative behavior. Overall, ß-CD might be used as a sulphur-containing volatile decreasing agent, which could keep the antioxidant properties of onion in the O/W emulsion.

Microwave resonator can help to predict oxidative stability in C18-based vegetable oils.

Effects of moisture content, degree of oxidation, degree of unsaturation of fatty acid compositions in C18-based edible oils were determined by a microwave resonator in the range of 0-4.4 GHz. Moisture content and degree of oxidation in corn oil made difference in signal intensity at 1.7-1.9 GHz and 1.0-1.2 GHz, respectively without uniform trend in signal intensity. Degree of unsaturation of C18-based edible oils including corn, sesame, soybean, olive, perilla, and flaxseed oils provided difference in 3.0-3.1 GHz with a dependent manner of degree of unsaturation. Average of signal intensity (ASI) in 3.0-3.1 GHz had high correlation (R2 > 0.93) to the degree of unsaturation in edible oils. Oils with high oleic acid had relatively low ASI while those with high linolenic acid had high ASI value. Oxidative stability of C18-based edible oils can be categorized successfully without fatty acid analysis using a microwave resonator.

Enhancing oxidative stability of tocopherol-enriched edible oils using short-term exposure to microwave irradiation.

The effect of microwave irradiation on the oxidative stability of tocopherol-enriched corn oil at temperatures of 60 or 100°C was evaluated using the Rancimat assay. Short durations of microwave treatment (1 min) on 10-g oil aliquots were found to increase the induction period of corn oil samples containing 500 and 1000 ppm tocopherol by 7.7% and 9.9%, respectively compared to control oils. The moisture content of tocopherol-enriched corn oil decreased by 15% compared to that of corn oil after 1 min of microwave treatment. At 100°C, 1000 ppm tocopherol-enriched corn oil received 3 min of microwave treatment had 5.8% and 9.9% lower primary and secondary oxidation products than control groups, respectively while this effect was not clearly observed for oils stored at 60°C. However, 15 min of microwave irradiation accelerated the rates of lipid oxidation in corn oils irrespective of the addition of tocopherol. Content of α- and γ-tocopherols in 1 min of microwave irradiated samples remained more by 28.8 and 5.8%, respectively than those of controls after 9 h heat treatment at 100°C. Overall, microwave irradiation within 3 min can increase the oxidative stability of 10 g-corn oils, especially at 100°C, which could be due to the reduced moisture content in the bulk oil matrix. Practical Application: A microwave oven is an irreplaceable home appliance and is widely used in households. Short time exposure to microwave irradiation can remove moisture efficiently from edible oils without the formation of oxidation products, which could increase the oxidative stability of these oils, especially under frying conditions. The results of this study can be utilized to ensure a longer shelf-life of fried products in the food industry by short time treatment of microwave irradiation.

Evaluation of solvent effects on the DPPH reactivity for determining the antioxidant activity in oil matrix.

Reactivity of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in methanol, ethanol, isopropanol, isooctane, and ethyl acetate, was evaluated to assess the antioxidant capabilities in medium chain triacylglycerol. DPPH loss values were obtained over 30 min, with sampling every 5 min. Even the same concentration of antioxidants showed different DPPH reactivity depending on solvent. In methanol, 5 min was enough for α-tocopherol to react with DPPH, whereas BHT did not react with DPPH even after 30 min. Gallate series showed higher DPPH reactivity than TBHQ, sesamol, or BHA in methanol, while lower reactivity in isooctane. Antioxidants in ethanol and isopropanol reacted with DPPH less efficiently compared to those in methanol, the exception being sesamol. DPPH reactivity of gallate series in isooctane was lower than that of sesamol, TBHQ, and α-tocopherol. Combinatorial usage of methanol and isooctane for DPPH reactivity could provide reliable information on the antioxidant capacities of chemicals in edible oils. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-020-00874-9.

Selection of Lactococcus lactis HY7803 for Glutamic Acid Production Based on Comparative Genomic Analysis.

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/µl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/µl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

Evaluation of the effects of aldehydes on association colloid properties and oxidative stability in bulk oils.

The effects of amphiphilic aldehydes, including propanal, hexanal, and nonanal, on the critical micelle concentration (CMC) of phospholipids, moisture content, and oxidative stability in soybean oil were evaluated. The selected aldehydes are typical secondary oxidation products from unsaturated fatty acids. Moisture content increased as aldehydes were added to soybean oil during thermal oxidation at a storage temperature of 50 or 100 °C. The CMC of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) increased as propanal and hexanal were added, whereas nonanal decreased the CMC of DOPC, which implies that aldehydes participate in forming association colloids in bulk oils. The addition of aldehydes increased the rates of lipid oxidation significantly in both 50 and 100 °C treatments (p < 0.05), with the effect being more evident in oils treated at 50 °C than at 100 °C. Therefore, aldehydes formed from lipid oxidation affected the association colloidal structures and oxidative stability in a bulk oil matrix.

Effects of plasma treatment on the oxidative stability of vegetable oil containing antioxidants.

Plasma, the fourth stage of matter, is a partially or wholly ionized state of gas. Degree of lipid oxidation and effects of antioxidants were evaluated in bulk oils at plasma treatment. Significant changes in the conjugated dienoic acid were induced after 10 min of plasma treatment, which corresponded to treatment for 2.5 h at 100 °C and 48 h at 60 °C. Tocopherol stability in the stripped corn oil was significantly higher than that in medium-chain triacylglycerol after the plasma treatment. The antioxidant capacities of 10 µM of α-tocopherol and sesamol were higher than that of ß-carotene, and synergistic effects among α-tocopherol, sesamol, and ß-carotene were not observed. Added α-tocopherol and sesamol decreased CDA formation by 33 and 30% compared to control samples after plasma treatment. Moisture content in oils decreased significantly about 20% moisture after 6 min plasma treatment. Lipid oxidation could be an important issue in plasma-treated lipid-rich products.

Comparison of the Protective Effects of Bee Venom Extracts with Varying PLA2 Compositions in a Mouse Model of Parkinson's Disease.

Bee venom contains a number of pharmacologically active components, including enzymes and polypeptides such as phospholipase A2 (PLA2) and melittin, which have been shown to exhibit therapeutic benefits, mainly via attenuation of inflammation, neurotoxicity, and nociception. The individual components of bee venom may manifest distinct biological actions and therapeutic potential. In this study, the potential mechanisms of action of PLA2 and melittin, among different compounds purified from honey bee venom, were evaluated against Parkinson's disease (PD). Notably, bee venom PLA2 (bvPLA2), but not melittin, exhibited neuroprotective activity against PD in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. MPTP-induced behavioral deficits were also abolished after bvPLA2 treatment, depending on the PLA2 content. Further, bvPLA2 administration activated regulatory T cells (Tregs) while inhibiting inflammatory T helper (Th) 1 and Th17 cells in the MPTP mouse model of PD. These results indicate that bvPLA2, but not melittin, protected against MPTP and alleviated inflammation in PD. Thus, bvPLA2 is a promising and effective therapeutic agent in Parkinson's disease.

Feasibility of hydroxypropyl methylcellulose oleogel as an animal fat replacer for meat patties.

Canola oil was successfully structured with foam-structured hydroxypropyl methylcellulose (HPMC) into solid-like oleogels, and the feasibility of the HPMC oleogels as a replacement for animal fat (beef tallow) was evaluated to reduce the level of saturated fat in meat patties. The textural properties (firmness and work of shear) of HPMC oleogels were higher than those of beef tallow and had a tendency to increase with increasing levels of HPMC in the oleogels. HPMC oleogels behaved rheologically like an elastic gel and also exhibited temperature-independent solid fat contents. They exhibited greater resistance against oxidation than the canola oil under the accelerated storage condition. When the beef tallow in the formulation of meat patties was replaced with HPMC oleogels at 50% and 100%, the cooking loss of the patties was significantly reduced, and their texture became much softer. Furthermore, the sensory evaluation indicated that the highest overall acceptability was attained at the 50% replacement level. The replacement of beef tallow with HPMC oleogels was significantly effective in reducing the ratio of saturated to unsaturated fat from 0.73 to 0.18, consequently producing meat patties with nutritional superiority.

Extraction of Green Tea Phenolics Using Water Bubbled with Gases.

Water was bubbled with gases including nitrogen (N2 ), oxygen (O2 ), hydrogen (H2 ), carbon dioxide (CO2 ), and air for 10 min and phenolics from green tea leaves were extracted using the prepared gas-bubbled water. To retain the gases in water, the extraction conditions were maintained in an air-tight container at room temperature under magnetic stirring. Radical scavenging ability, total phenolic content, and phenolic profiles of the extracts were analyzed, and gas-bubbled water was examined to explain the differences in phenolic contents. Overall, green tea infusion prepared from H2 -bubbled water contained significantly high levels of total phenolic compounds and antioxidant activity compared to other gas-bubbled waters including N2 , O2 , CO2 , and air (P < 0.05).Control samples and those bubbled with CO2 showed the lowest antioxidant activities in green tea infusion. However, green tea extracts with O2 bubbling showed the lowest catechin content. Green tea leaves treated with hydrogen gas-bubbled water had much greater damage to their surface morphological properties compared to the other groups, which may explain the higher yield of phenolic compounds. Overall, hydrogen gas-bubbled water showed better extraction yield of phenolics from green tea leaves than other gas-bubbled water. PRACTICAL APPLICATION: Green tea or green tea infusion has diverse health beneficial functionality due to the presence of phenolic compounds. In this study, different gases including nitrogen, oxygen, hydrogen, and carbon dioxide were treated in water and these gas-bubbled water were used to extract phenolics from green tea leaves. Among them, hydrogen-bubbled water extracted the highest phenolic contents from tea leaves and showed the highest in vitro antioxidant ability in green tea infusion compared to other gas-bubbled water. This new knowledge could help to produce green teas with higher antioxidant activity in beverage industry.

Addition of Sesamol Increases the Oxidative Stability of Beeswax Organogels and Beef Tallow Matrix Under UV Light Irradiation and Thermal Oxidation.

To enhance the oxidative stability of organogels made from canola oil, 40 ppm sesamol was added to beeswax-based organogels stored under ultraviolet (UV) light irradiation and 60 or 100 °C thermal oxidation conditions. To study the practical application of organogels as animal fat substitutes, beef tallow was mixed with organogels and their oxidative stability was determined under oxidative stress conditions. Without sesamol addition, the organogels and beef tallow with organogel oxidized rapidly under UV irradiation and thermal oxidation. The addition of 40-ppm sesamol decreased the consumption of headspace oxygen and the formation of primary and secondary oxidation products significantly (P < 0.05) compared with those in samples without the addition of sesamol, irrespective of oxidative stress. Sesamol improved the oxidative stability of organogels and beef tallow with organogel, which could be used in the meat industry. PRACTICAL APPLICATION: Organogels may replace trans-fat or highly saturated lipids in food products. The high degree of unsaturation and processing temperature mean that antioxidants are needed to extend the shelf life of organogels or organogel-containing products. The addition of sesamol significantly enhanced the oxidative stability of organogels and of beef tallow-containing organogels under UV irradiation and thermal oxidation conditions. Therefore, sesamol-supplemented organogels could replace saturated fats in beef tallow and prolong the shelf-life of meat products.

Prediction of oxidative stability in bulk oils using dielectric constant changes.

The effects of amphiphilic compounds on the dielectric constant of bulk oils were determined and the utility of the dielectric constant as a reliable parameter for predicting the oxidative stability of edible oils was evaluated. As the content of monoacylglycerols (MAGs), lecithin, and moisture increased, the dielectric constant of modified corn oil increased at different rates, whereas the addition of free fatty acids, including oleic and linoleic acid, decreased the dielectric constant of modified corn oil. Unoxidized fresh bulk oils showed a wide range of dielectric constants, from 8 for canola oils to 33 for flaxseed oils. The dielectric constant showed a strong correlation with the percentage of unsaturated fatty acids in the bulk oils. Oils with low oxidative stability had a high dielectric constant. Overall, the dielectric constant of bulk oils is strongly correlated with the content of amphiphilic compounds, moisture content, and degree of unsaturation of fatty acids.

Chemical profiles and antioxidant properties of roasted rice hull extracts in bulk oil and oil-in-water emulsion.

We conducted in vitro assays to investigate the antioxidant properties of aqueous or ethanolic extracts of roasted rice hulls. Phenolic compound contents were analyzed via HPLC, and comprehensive chemical profiles were obtained via 1H NMR and 1H-H COSY NMR. Rice hulls were roasted at 150, 180, and 230 °C for 20 min, after which the aqueous and 70% ethanol extracts were obtained. In vitro assays showed that rice hulls roasted at 230 °C possessed very strong antioxidant properties (p < 0.05). Comprehensive chemical profiles determined via NMR showed that roasting increased the contents of specific amino acids and monosaccharides and reduced the organic acid contents. p-Coumaric, vanillic, and ferulic acids were the most dominant phenolic compounds present in the sample. Added roasted rice hull extracts enhanced the oxidative stability of bulk oil and in O/W emulsions at 60 °C. However, the extracts accelerated lipid oxidation rates of oils heated at 180 °C.

Alleviation effects of natural volatile organic compounds from Pinus densiflora and Chamaecyparis obtusa on systemic and pulmonary inflammation.

Chamaecyparis obtusa (C. obtusa) and Pinus densiflora (P. densiflora) have been traditionally used as antibiotic, antinociceptive and anti-inflammatory agents in Asian folk medicine. Recent studies have demonstrated antioxidant, antiproliferative and anti-inflammatory effects of C. obtusa and P. densiflora extracts. In the present study, volatile organic compounds (VOCs) of C. obtusa and P. densiflora were examined to determine whether they have anti-inflammatory capabilities. To evaluate the anti-inflammatory effects of VOCs of C. obtusa and P. densiflora, lipopolysaccharide (LPS) was administered to the lung by nasal injection and to the whole body by intraperitoneal injection. Alterations in serum immunoglobulin E (IgE) levels and prostaglandin E2 (PgE2) were examined using ELISA. LPS-increased serum IgE and PgE2 levels were recovered by administration of dexamethasone and VOCs of C. obtusa and P. densiflora. Levels of mRNA expression of inflammatory cytokines were determined in an LPS-induced inflammation mouse model. Reverse transcription-quantitative polymerase chain reaction was used to determine the mRNA expression levels of cyclooxygenase 2, interleukin (IL)-1ß, tumor necrosis factor (TNF)-α and IL-13 in peripheral blood mononuclear cells. The expression of all examined cytokine mRNAs increased by LPS was suppressed by dexamethasone and VOCs of C. obtusa and P. densiflora. Similar tendencies were observed in lung tissues and cells obtained via bronchoalveolar lavage. The results of the present study suggested that VOCs of C. obtusa and P. densiflora, through their immunosuppressive activities, may have therapeutic potential in the treatment or prevention of inflammation.

The critical micelle concentration of lecithin in bulk oils and medium chain triacylglycerol is influenced by moisture content and total polar materials.

Effects of different moisture contents and oxidised compounds on the critical micelle concentration (CMC) of lecithin were determined in bulk oils and in medium-chain triacylglycerols (MCT). CMC of lecithin in MCT was significantly higher than that in other vegetable oils including olive, soybean, corn, and rapeseed oils (p < 0.05). Presence of moisture significantly affected the CMC of lecithin in MCT (p < 0.05). CMC of lecithin was high when the moisture content was below 900 ppm, whereas at a moisture content of 1000 ppm, CMC of lecithin decreased significantly (p < 0.05), and then started to increase. Addition of total polar materials (TPM), which are oxidation products, at 3 and 5% concentrations, decreased CMC of lecithin significantly (p < 0.05) in MCT, compared to when 0, 1, and 1.5% of TPM was added to MCT. As the degree of oxidation increased in corn oil, CMC of lecithin gradually decreased. Additionally, under different moisture contents, corn oils showed a similar pattern of CMC of lecithin in MCT, whereas oxidised corn oil had a little lower CMC of lecithin than unoxidised corn oil. The results clearly showed that the concentration of lecithin for the formation of micelles is greatly influenced by the presence of oxidation products and the moisture content in bulk oils.

Effects of Hydrogen-Donating or Metal-Chelating Antioxidants on the Oxidative Stability of Organogels Made of Beeswax and Grapeseed Oil Exposed to Light Irradiation.

To enhance the oxidative stability of organogels made from grapeseed oil, the antioxidant effects of sesamol, α-tocopherol, ß-carotene, ethylenediaminetetraacetic acid (EDTA), and citric acid were determined in beeswax-based organogels stored under light or in the dark conditions at 25 °C. Without the addition of antioxidants, the organogels rapidly oxidized under light irradiation but not during storage in the dark. Sesamol showed the highest antioxidant activity at concentrations of 10 to 40 ppm, whereas the other compounds exhibited no antioxidant activity at 10 ppm. α-Tocopherol and ß-carotene improved the oxidative stability of organogels at concentrations above 40 and 100 ppm, respectively. The addition of sesamol yielded better oxidative stability than the addition of EDTA or a mixture of sesamol and citric acid. Sesamol can improve the oxidative stability of organogels, which could lead to economic benefits for the food industry. PRACTICAL APPLICATION: Recently, interest in organogels has increased due to their properties of maintaining a solid state at room temperature and composition of trans-free and highly unsaturated fatty acids. However, the addition of antioxidants is necessary due to the high degree of unsaturation in organogels. The results of this study showed that the addition of sesamol significantly enhanced the oxidative stability of organogels under light irradiation. Therefore, the use of sesamol-supplemented organogels could prolong the shelf-life of bakery or meat food products.

Enhancing oxidative stability in heated oils using core/shell structures of collagen and α-tocopherol complex.

In this study, collagen mesh structure was prepared by carrying α-tocopherol in the form of core/shell complex. Antioxidant properties of α-tocopherol loaded carriers were tested in moisture added bulk oils at 140°C. From one gram of collagen core/shell complex, 138mg α-tocopherol was released in medium chain triacylglycerol (MCT). α-Tocopherol was substantially protected against heat treatment when α-tocopherol was complexed in collagen core/shell. Oxidative stability in bulk oil was significantly enhanced by added collagen mesh structure or collagen core/shell complex with α-tocopherol compared to that in control bulk oils (p<0.05), although no significant difference was observed between oils containing collagen mesh structure and collagen core/shell with α-tocopherol (p>0.05). Results of DPPH loss in methanol demonstrated that collagen core/shell with α-tocopherol had significantly (p<0.05) higher antioxidant properties than collagen mesh structure up to a certain period. Therefore, collagen core/shell complex is a promising way to enhance the stability of α-tocopherol and oxidative stability in oil-rich foods prepared at high temperature.

Utilization of Oleogels as a Replacement for Solid Fat in Aerated Baked Goods: Physicochemical, Rheological, and Tomographic Characterization.

Canola oil-carnauba wax oleogels were evaluated as a replacement for shortening in a baked cake system. The use of oleogels produced cake batters with a lower pseudoplastic property and also contributed to their viscous nature. The shortening replacement with oleogels at up to 50% was effective in maintaining the ability to hold air cells into the cake batters. The volume of cakes had an overall tendency to decrease with increasing shortening replacement with oleogels, leading to increased cake firmness. The tomographic analysis demonstrated that the total porosity and fragmentation index were reduced in the oleogel cakes, showing a more connected solid structure. The levels of saturated fatty acids in the cakes containing oleogels were significantly reduced to 13.3%, compared to the control with shortening (74.2%). As a result, the use of oleogels for shortening up to 25% produced cakes with lower levels of saturated fatty acids without quality loss.

Effect of shortening replacement with oleogels on the rheological and tomographic characteristics of aerated baked goods.

BACKGROUND: A great deal of effort has been made to reduce the use of shortening owing to the high level of saturated fats as well as the presence of trans fats. Grape seed oil high in unsaturated fats was structured with candelilla wax to form solid-like oleogels that were utilized as a shortening replacer in aerated baked goods, specifically muffins. RESULTS: Muffin batters with greater amounts of oleogels exhibited lower viscosity, greater shear-thinning behavior and less elastic nature. The shortening replacement with oleogels significantly increased the specific gravity of the batters, consequently affecting the muffin volume after baking. X-ray tomography indicated a lower fragmentation index (i.e. a more connected solid structure) in the oleogel-incorporated muffins, which was correlated with more enclosed and isolated air cells. A stress relaxation test showed that the shortening replacement with oleogels produced muffins with a firmer and springier texture. Based on fatty acid compositions, the ratio of saturated to unsaturated fatty acids was significantly reduced from 2.81 to 0.41. CONCLUSION: Use of the oleogels as a shortening replacer at a ratio of 1:3 by weight was effective in producing muffins with comparable quality attributes to the control with shortening. © 2017 Society of Chemical Industry.

Monitoring changes in acid value, total polar material, and antioxidant capacity of oils used for frying chicken.

Oxidation products and tocol homologues were monitored in oils during chicken frying to determine the discarding point of highly used frying oils. Oils were heated without chicken for 170h while chicken frying was performed 130 cycles at 180°C. As heating time and frying cycles increased, all oxidation parameters including acid value, total polar materials (TPM), conjugated dienoic acid (CDA), and p-anisidine values (p-AV) increased significantly (p<0.05). γ-Tocopherol and γ-tocotrienol had the lowest stability in oils during heating or frying processes compared to other tocol homologues. TPM values over 24% were obtained after about 109h for heated oil and 100 cycles for oils used to fry chicken. A decrease of 2,2-diphenyl-1-picrylhydrazyl (DPPH) in isooctane and methanol was highly correlated with the formation of TPM in oils during the frying process. Both DPPH loss and TPM values could be applied to determine the discarding points of highly used frying oils.