Journal of the American Oil Chemists Society最新文献

Preventing metal-catalyzed lipid oxidation in food products, which decreases nutritional value and sensory quality, is crucial in the food industry. This is typically achieved through the use of metal-chelating molecules. While the ferrozine assay is widely used to screen protein hydrolysates for metal chelating activity, it has proven difficult to use with pure peptides. This study evaluates the potential of surface plasmon resonance (SPR) and electrically switchable nanolever technology (switchSENSE®) as alternative screening methods. Unfortunately, solubility issues and large standard deviations precluded a direct correlation between the ferrozine assay and these biosensor techniques. Both techniques, however, were able to quantitatively distinguish between two peptides with very similar sequences despite the absence of a correlation between dissociation constants determined by SPR and switchSENSE®. This study highlights the potential of SPR and switchSENSE® for screening the metal chelating activity of pure peptides, advancing the understanding of peptide-metal ion interactions.

Palm oil processing can result in different food products like cooking oil and margarine. Nevertheless, these food products might contain harmful contaminants, namely 3-monochloropropane-1,2-diol ester (3-MCPDE) and glycidyl ester (GE), which can negatively affect animal organs and potentially cause human cancer. Therefore, the objective of this study was to lower the concentration of 3-MCPDE and GE in refined, bleached, and deodorized palm oil (RBDPO) using zeolite as an adsorbent. Adsorption experiments were conducted in a batch reactor, varying the percentage of adsorbents, temperature, type of zeolite, and the use of a mixture of zeolite and activated carbon (AC). The sample was analyzed before and after adsorption using gas chromatography–mass spectroscopy (GC–MS) to confirm the concentration alteration of 3-MCPDE and GE. The study showed that the most effective temperature for adsorption was 35°C and used a zeolite percentage of 2%. Beta zeolites resulted in the highest removal of 3-MCPDE (86%) among the evaluated zeolites attributed to their elevated pore volume, Si/Al ratio, and overall acidity strength. Through a synergistic combination of beta zeolite and AC, the removal percentage of 3-MCPDE was enhanced to 94%, with a corresponding 75% reduction in GE. This study paves the way for addressing 3-MCPDE and GE concerns in RBDPO by combining zeolite and AC.

In this study, it was aimed to determine the effects of different production and preservation methods on the shelf life and quality of the Gemlik variety of natural black table olives produced with low salt (2%). For this purpose, olives were processed by the traditional Turkish style dry salted black olive by using a starter culture. The MAP (Modified atmosphere packaging, 60% N₂ and 40% CO₂), vacuum and for the first time gamma irradiation methods (1, 3 and 5 kGy) were applied in the preservation of table olives. The 5 kGy irradiation treatment reduced the total phenolic amount and DPPH antioxidant activity of olives more than other irradiation doses. The pH (4.3–4.83) and titratable acidity (0.68–1.02%) of the samples changed in accordance with the legal regulations during the storage period (pH max. 5 and acidity min 0.3%). At the end of the fermentation and storage, total phenolic content and antioxidant activity decreased significantly (p-value <0.05). During the storage period, the total phenolic content in natural fermented olives (without starter culture) decreased from 232 to 144 mgCAE/100 g and in starter culture added table olives from 200 to 138 mgCAE/100 g. In addition, the antioxidant activity was changed between 60.94 and 47.14 μmolTE/100 g oil. As a result of the study, it was ensured that black table olives produced with less salt (2%) could be stored on the shelves for 6 months without using any preservatives. In addition, radiation effect on quality was relatively similar to other treatments (vacuum and MAP).

Descriptive sensory analysis discriminated between the appearance, aroma, flavor, taste and texture of Cheddar cheese samples prepared from milk varying in fat globule size; small milk fat globule milk (SMM, d_4,3 = 2.76 ± 0.07 μm), large milk fat globule milk (LMM, d_4,3 = 5.07 ± 0.06 μm) and Control (d_4,3 = 3.91 ± 0.09 μm), over a six-month maturation period. Significant differences were measured between SMM, LMM and the Control as each cheese matured, where SMM was the most different across all parameters examined. SMM was lowest in color intensity (34.6 < 38.8–47.0), firmness (29.4 < 36.1–47.7), and fracturability (24.5 < 28.8–30.7), and highest in cohesiveness (57.0 > 39.8–45.8), adhesiveness (52.9 > 39.0–45.4), and smoothness (50.4 > 37.9–44.0). Moreover, SMM was more intense than the Control in cultured odor (34.9 > 29.6–30.6) and flavor (45.5 > 34.9–36.2), rancid (23.3 > 16.0–18.6) and metallic (17.7 > 14.3) flavor, salty taste (45.7 > 40.3–40.5) and aftertaste (38.5 > 34.9–35.8), sour (36.3 > 28.9) and umami taste (19.6 > 16.4); attributes that align with the degree of maturation. LMM showed similar differences to the Control, but was firmer (36.1 > 29.4), less cohesive (45.8 < 57.0), adhesive (45.4 < 52.9) and smooth (44.0 < 50.4) and had a less intense cultured odor (31.5 < 34.9) than SMM. An increase in salty taste was associated with a decrease in cheese firmness (−0.91, p < 0.0001). These results could provide process-driven solutions that allow the dairy industry to decrease maturation time or create differentiated cheese products to meet specific consumer tastes or function.

In the present study, various factors including carbon source, nitrogen source, Mg²⁺, and pH value were investigated to determine the optimal conditions for producing cocoa butter equivalent using R. toruloides. The maximum of biomass, lipid content, and lipid production were achieved at levels of 7.8 g/L, 61.0%, and 4.4 g/L, respectively. The oil from R. toruloides mainly consisted of 16:0, 18:0, and 18:1 with 18:1 dominating at the sn-2 position, which was further confirmed by ¹³C NMR analysis. UPLC-MS analysis showed that the sum of sn-POP, sn-POS, and sn-SOS accounted for up to 27.11% in the triacylglycerol species of the oil produced, which allows those triacylglycerols to be further separated and isolated from other triacylglycerols and used for cocoa butter equivalent. Notably, the production of cocoa butter equivalent reached 1.13 g/L, demonstrating the scientific feasibility of producing CBE through fermentation. These findings indicate a promising future for the fermentation-based production of cocoa butter equivalent.

SOS-rich fats have been developed to improve heat stable properties and fat bloom-resistant abilities of chocolates, which is highly connected with their crystallization behaviors. Shea butter stearin (SBS) and mango kernel fat (MKF) are the typical SOS-rich fats. Both contained high levels of stearic acid (45.06%–59.67%) and oleic acid (31.85%–39.97%), while 77.00%–86.88% of the oleic acid were distributed at the sn-2 positions of triacylglycerol molecules, contributing to forming 78.04% of SOS in SBS and 47.85% of SOS in MKF. Their SOS levels were significantly higher than that in cocoa butter (CB, 25.43%). However, MKF contained the highest levels of SOO (15.59%), which was about six to eight times as likely that in SBS and CB (1.76%–2.66%). Further crystallization tests revealed that SBS and MKF exhibited similar rod-like growth from instantaneous nuclei at 4°C. The former was then changed to become more spherulitic growth at 20°C significantly. Specifically, large feather-like crystals corresponding to β form were observed in SBS at the final stage of crystallization at 20 and 30°C, while MKF exhibited smaller crystals. The higher concentration of SOO in MKF was considered as the softening factor. It was further supposed that constant crystallization at 20°C may be difficult for some fats (e.g., SOS < 30%) to form adequate amounts of β crystals. The results will provide information on making cocoa butter blends and chocolate tempering.

Rhizopus oryzae lipase (ROL) is known to present high selectivity in chemical reactions. However, the poor stability of ROL effectively limits its industrial applications. In this study, several immobilization protocols, such as hydrophobic adsorption, covalent immobilization, multi-point covalent attachment, ionic adsorption/cross-linking, and ionic interaction, were applied to improve the stability of ROL. Heterogeneous modification of aspartic and glutamic acid residues on the surface of ROL was carried out by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) to introduce new amine groups with lower pKb. The highest immobilization yield of 89% was achieved for octyl-agarose, producing specific activity of 45 U/mg, which is 15 folds higher than the specific activity of the soluble enzyme. Improved stability of ROL was observed, in particular for those derivatives obtained by multi-point covalent attachment of ROL on glyoxyl-agarose (Gx-ROL) and aminated ROL on glyoxyl-agarose (Gx-NH₂-ROL) by retaining 28%–36% of their initial activities after 24 h incubation at 60°C. Immobilization also altered the co-solvent stability profile of the immobilized derivatives producing biocatalysts with varied co-solvent stabilities. Furthermore, utilization of the immobilized preparations in fish oil hydrolysis revealed the selective release of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) in favor of EPA. The highest EPA/DHA selectivity of 33 was observed for the hydrophobically immobilized ROL on octyl-sepharose.

The plasticity of the lipid profile of soybean oil has made the soybean a crop with value in feed, food and industrial uses. Soybean oil typically consists of approximately 10% of the fully saturated palmitic acid, which has value for industrial purposes, however it is generally undesirable in food applications. Two soybean KASII (ketoacyl-ACP synthase II) genes have been previously implicated in the control of seed palmitic acid levels. Using forward genetics, we isolated four novel alleles in the GmKASIIB gene that result in increased levels of palmitic acid, ranging from 13% to 16% of the total fatty acid content, over multiple seasons in the field. Three of the KASIIB mutations result in independent amino acid substitutions at conserved positions in the KASII protein, and one single nucleotide polymorphism is likely to cause aberrant splicing of the KASIIB transcript. These new mutations can be used in breeding applications to increase palmitic acid content and to probe the control of fatty acid biosynthesis in soybean seeds.

New alleles of the GmKASIIb gene result in increased levels of palmitic acid in soybean seeds.

This paper identifies physical properties of an interesterified palm-based fat (EIEPO) that predict oil binding capacity (OBC). A 100% EIEPO sample, 50% EIEPO sample diluted with 50% soybean oil (SBO), and a 20% EIEPO sample diluted with 80% SBO were used to test how saturation level impacts OBC. All samples were crystallized using either a fast (6.4°C/min) or slow (0.1°C/min) cooling rate as well as with or without the application of high-intensity ultrasound (HIU; 20 kHz) to generate a wide range of physical properties. Immediately after crystallization, the sample's physical properties, including crystal microstructure, solid fat content (SFC), viscoelasticity (G′, G″, and δ), melting behavior, hardness, and OBC (centrifuge method) were quantified. The samples were then stored for 48 h at 22 and 5°C and the aforementioned physical properties were measured again, with one additional measurement for the samples stored at 5°C—OBC using a filter paper method (OBC_p). The results indicate that OBC can be optimized in a palm-based fat by modifying the physical properties which was achieved via the processing conditions. Both measurements of OBC were significantly correlated with SFC, hardness, δ, and enthalpy. A model was developed to predict a sample's OBC_c using the following dominant variables—SFC, hardness, peak temperature, enthalpy, and the number of crystals. These results suggest that OBC can be predicted using a sample's SFC, hardness, peak temperature, enthalpy, and number of crystals and that SFC, hardness, and enthalpy are main drivers of OBC.

Borage seed oil (BSO; Borago officinalis L.) has great medicinal and nutritional potential owing to its bioactive components. In this study, we compared the lipid composition, micronutrient content, free radical scavenging capacities, and cellular antioxidant and antiproliferative activities of BSO from eight provinces in China. The Gansu sample had the highest levels of γ-linolenic acid, accounting for 18.66%. We detected more than 17 triacylglycerols in BSO. Among micronutrients, δ-tocopherol and Δ5-avenasterol were the main components of tocopherol and phytosterol, respectively. The highest cellular antioxidant activity values were found in the Shanxi and Gansu samples; the concentration cytotoxicity 50% values were higher than 200 mg/mL, and the median effective dose ranged from 18.34 ± 0.52 to 70.65 ± 1.76 mg/mL. In addition, we tested the free radical scavenging capacity of BSO and found significant differences in antioxidant capacity between samples from different regions, and the Gansu sample had a better antioxidant capacity.