Evaluation of the composition and oxidative status of omega-3 fatty acid supplements on the Finnish market using NMR and SPME-GC–MS in comparison with conventional methods

Comprehensive lipidomics and flavoromics reveals the accelerated oxidation mechanism of fish oil from silver carp (Hypophthalmichthys molitrix) viscera during heating

This study employed gas chromatography-mass spectrometry (GC-MS) and lipidomic approaches to analyze volatile organic compounds (VOCs) and lipid dynamics in silver carp visceral fish oil during accelerated oxidation at 60 °C. The lipidomic profiling revealed 1362 distinct lipid molecules, encompassing 92 fatty acids. Triglycerides (TGs) underwent degradation in the early oxidation phase (0-6 days), whereas glycerophospholipid breakdown dominated the later stages (9-20 days). Among 44 detected VOCs, six compounds including nonanal, (E,E)-2,4-heptadienal, (E)-2-nonenal, (E)-2-decenal, 1-octen-3-ol, and eugenol were identified as critical flavor contributors based on odor activity values (OAV) exceeding 1.0. Notably, 1-octen-3-ol and (E)-2-decenal were hypothesized to derive from phosphatidylethanolamine (PE), TG, and ceramide (Cer) degradation. Key lipid classes linked to flavor deterioration included PE with odd-chain and unsaturated fatty acids (UFAs), TG rich in polyunsaturated fatty acids (PUFAs), and Cer containing monounsaturated fatty acids (MUFAs). These insights enhance mechanistic understanding of oxidative flavor changes in fish oils.

A novel micro-aqueous cold extraction of salmon head oil to reduce lipid oxidation and fishy odor: Comparison with common methods

Traditional heat extraction (HE) has a low efficiency (75.2 wt%) and induces lipid oxidation of PUFAs. The novel micro-aqueous cold (<25 °C) extraction (MAE) was applied to extract salmon head oil. The recovery rate was 93.4 wt% at oil volume fraction Φ = 74 %. The extraction mechanism was agitation-induced droplet coalescence at an unstable and close-packing state (Φ = 74 %), increasing the portions of the large-sized droplets (>50 μm) from 2.8 vol% to 91.7 vol%. The MAE reduced the oil oxidation level and odor intensity compared to HE, although the lipid profile differed slightly. The HE head oil had more key fishy odor compounds, including hexanal (0.98 mg/kg), 3-methyl-butanal (0.25 mg/kg), 1-penten-3-ol (0.49 mg/kg), and 2-ethylfuran (0.19 mg/kg). The MAE oil had only 2-methyl-butanal (0.10 mg/kg) and 1-penten-3-ol (0.47 mg/kg). Overall, micro-aqueous extraction has great potential to replace industrial heat extraction with a better product quality.

Lipid and volatile profiles of Finnish oat batches of pure cultivars: Effect of storage on the volatile formation

Recent data showing the compositional variation and storage behavior among different oat batches for the purpose of food remains limited. Lipids of twenty oat flour samples of pure cultivars grown in Finland during 2019 were extracted and fractionated into neutral and polar-rich lipids. Flour was stored for nine months, and profiles of volatiles and tocols were analyzed to reveal oxidative stability. The lipid content was 5.9-8.9 g per 100 g of flour [DW] and consisted of 78.7 ± 2.5 % neutral and 21.3 ± 2.5 % polar lipids. Palmitic (16 %), oleic (36 %), and linoleic (39 %) acids were the most abundant fatty acids. Neutral lipids had more oleic and less linoleic and palmitic acids than polar lipids. The fresh samples correlated with tocols, pentanal, 2-pentylfuran, 2-heptanone, nonanal, 2-butanone, and heptanal, while stored samples were associated with 3-octen-2-one, 2-octenal, hexanal, and octanal. Lipid composition and oxidative stability are essential factors for selecting oat batches for food applications.

Thermal oxidation mechanism of palmitic aicd

The oxidation and degradation of fats lead to a decrease in the nutritional value of food and pose safety concerns. Saturated fatty acids also hold a significant position in the field of lipid oxidation. In this study, the oxidation products of methyl palmitate were investigated by using gas chromatography mass spectrometry (GC-MS). Seven monohydroperoxides and 72 secondary oxidation products were detected. Combined with density functional theory (DFT) calculations, the formation mechanisms of oxidation products can be summarized into four stages. The initial stage involved the formation of monohydroperoxides and alkanes, followed by the subsequent stage involving methyl x-oxo(hydroxy)hexadecanoates. The third stage involved the formation of methyl ketones, carboxylic acids, and aldehydes, while the final stage involved lactones. Meanwhile, methyl ketones were the most abundant oxidation product, approximately 25 times more abundant than aldehydes; the calculated results agreed well with the experimental results. The establishment of a comprehensive thermal oxidation mechanism for palmitic acid provided a new foundation for future lipid oxidation analyses.

Characterization of fatty acid forms using benchtop NMR in omega-3 oil supplements

Omega-3 fatty acid supplements, such as fish oil and plant-based oils, have gained popularity because of their potential health benefits. However, the quality and composition of these supplements can vary widely, particularly in terms of the two main forms of omega-3 fatty acids: triacylglycerols (TAGs) and ethyl esters (EEs). TAGs are the natural form found in fish oil but are prone to oxidation, whereas EEs are more stable but less well absorbed by the body. Differentiating between these forms is crucial for assessing the efficacy and tolerance of omega-3 supplements. This article describes a novel approach to differentiate between TAG and EE forms of omega-3 fatty acids in dietary supplements, utilizing a 60-MHz benchtop nuclear magnetic resonance (NMR) spectrometer. The proposed method using 1H and 1H-1H COSY NMR provides a quick and accurate approach to screen the forms of omega-3 fatty acids and evaluate their ratios. The presence of diacylglycerol (DAGs) in some supplements was also highlighted by this method and adds some information about the process used (i.e., esterification/enrichment). The affordability and user-friendliness of benchtop NMR equipment make this method feasible for food processing companies or quality control laboratories. In this study, 24 oil supplements were analyzed using NMR analysis in order to demonstrate the potential of this method for the differentiation of TAG and EE forms in omega-3 supplements.

Fish oil-loaded multicore submillimeter-sized capsules prepared with monoaxial electrospraying, chitosan-tripolyphosphate ionotropic gelation, and Tween blending

In order to load fish oil for potential encapsulation of fat-soluble functional active substances, fish oil-loaded multicore submillimeter-sized capsules were prepared with a combination method of three strategies (monoaxial electrospraying, chitosan-tripolyphosphate ionotropic gelation, and Tween blending). The chitosan-tripolyphosphate/Tween (20, 40, 60, and 80) capsules had smaller and evener fish oil cores than the chitosan-tripolyphosphate capsules, which resulted from that Tween addition induced smaller and evener fish oil droplets in the emulsions. Tween addition decreased the water contents from 56.6 % to 35.0 %-43.4 %, increased the loading capacities from 10.4 % to 12.7 %-17.2 %, and increased encapsulation efficiencies from 97.4 % to 97.8 %-99.1 %. In addition, Tween addition also decreased the highest peroxide values from 417 meq/kg oil to 173-262 meq/kg oil. These properties' changes might result from the structural differences between the chitosan-tripolyphosphate and chitosan-tripolyphosphate/Tween capsules. All the results suggested that the obtained chitosan-tripolyphosphate/Tween capsules are promising carriers for fish oil encapsulation. This work also provided useful knowledge to understand the preparation, structural, and physicochemical properties of the chitosan-tripolyphosphate capsules.

Influence of solvent-free extraction of fish oil from catfish (Clarias magur) heads using a Taguchi orthogonal array design: A qualitative and quantitative approach

This study aimed to efficiently utilize catfish heads, enhancing the oil extraction process while improving the cost-effectiveness of fish byproduct management. The study employed the wet rendering method, a solvent-free approach, utilizing a two-factor Taguchi orthogonal array design to identify critical parameters for optimizing oil yield and ensuring high-quality oil attributes. The extraction temperature (80-120°C) and time (5-25 min) were chosen as variables in the wet rendering process. Range analysis identified the extraction time as a more significant (p < 0.05) factor for most parameters, including oil yield, oil recovery, acid value, free fatty acids, peroxide value, and thiobarbituric acid reactive substances. The extraction temperature was more significant (p < 0.05) for oil color. Consequently, the wet rendering method was optimized, resulting in an extraction temperature of 80°C and an extraction time of 25 min, yielding the highest oil yield. This optimized wet rendering process recovered 6.37 g/100 g of oil with an impressive 54.16% oil recovery rate, demonstrating comparable performance to traditional solvent extraction methods. Moreover, Fourier transfer infrared spectra analysis revealed distinct peaks associated with triacylglycerols and polyunsaturated fatty acids (PUFA). The oil recovered under optimized conditions contained higher levels of PUFA, including oleic acid (189.92 μg/g of oil), linoleic acid (169.92 μg/g of oil), eicosapentaenoic acid (17.41 μg/g of oil), and docosahexaenoic acid (20.82 μg/g of oil). Volatile compound analysis revealed lower levels of secondary oxidation compounds under optimized conditions. This optimized wet rendering method offers practical advantages in terms of cost-efficiency, sustainability, reduced environmental impact, and enhanced oil quality, making it an attractive option for the fish processing industries. Future research possibilities may include the purification of the catfish head oil and its application in the food and pharmaceutical industries.

An overview of food lipids toward food lipidomics

Increasing evidence regarding lipids' beneficial effects on human health has changed the common perception of consumers and dietary officials about the role(s) of food lipids in a healthy diet. However, lipids are a wide group of molecules with specific nutritional and bioactive properties. To understand their true nutritional and functional value, robust methods are needed for accurate identification and quantification. Specific analytical strategies are crucial to target specific classes, especially the ones present in trace amounts. Finding a unique and comprehensive methodology to cover the full lipidome of each foodstuff is still a challenge. This review presents an overview of the lipids nutritionally relevant in foods and new trends in food lipid analysis for each type/class of lipids. Food lipid classes are described following the LipidMaps classification, fatty acids, endocannabinoids, waxes, C8 compounds, glycerophospholipids, glycerolipids (i.e., glycolipids, betaine lipids, and triglycerides), sphingolipids, sterols, sercosterols (vitamin D), isoprenoids (i.e., carotenoids and retinoids (vitamin A)), quinones (i.e., coenzyme Q, vitamin K, and vitamin E), terpenes, oxidized lipids, and oxylipin are highlighted. The uniqueness of each food group: oil-, protein-, and starch-rich, as well as marine foods, fruits, and vegetables (water-rich) regarding its lipid composition, is included. The effect of cooking, food processing, and storage, in addition to the importance of lipidomics in food quality and authenticity, are also discussed. A critical review of challenges and future trends of the analytical approaches and computational methods in global food lipidomics as the basis to increase consumer awareness of the significant role of lipids in food quality and food security worldwide is presented.

Lipid Structure Influences the Digestion and Oxidation Behavior of Docosahexaenoic and Eicosapentaenoic Acids in the Simulated Digestion System

Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for human health but prone to oxidation. While esterification location is known to influence the stability of omega-3 in triacylglycerols (TAGs) in oxidation trials, their oxidative behavior in the gastrointestinal tract is unknown. Synthesized ABA- and AAB-type TAGs containing DHA and EPA were submitted to static in vitro digestion for the first time. Tridocosahexaenoin and DHA as ethyl esters were similarly digested. Digesta were analyzed by gas chromatography, liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. Besides the formation of di- and monoacylglycerols, degradation of hydroperoxides was detected in ABA- and AAB-type TAGs, whereas oxygenated species increased in tridocosahexaenoin. Ethyl esters were mainly unaffected. EPA was expectedly less susceptible to oxidation prior to and during the digestion process, particularly in sn-2. These results are relevant for the production of tailored omega-3 structures to be used as supplements or ingredients.

Enzyme-assisted aqueous extraction of fish oil from Baltic herring (Clupea harengus membras) with special reference to emulsion-formation, extraction efficiency, and composition of crude oil

Enzyme-assisted aqueous extraction (EAAE) is a green, and scalable method to produce oil and protein hydrolysates from fish. This study investigated the role of different parameters on emulsion formation, oil recovery, and the composition of crude oil during EAAE of Baltic herring (Clupea harengus membras). Fatty acid compositions, lipid classes, tocopherols, and oxidation status of the EAAE crude oils were studied. Compared to solvent-extracted oil, EAAE resulted in a lower content of phospholipids accompanied by a 57% decrease in docosahexaenoic acid. Changing fish to water ratio from 1:1 to 2:1 (w/w) with ethanol addition led to the greatest reduction (72%) of emulsion, which resulted in an increase in oil recovery by 11%. The addition of ethanol alone, or reduction of enzyme concentration from 0.4% to 0.1% also reduced emulsion-formation significantly. Overall, emulsion reduction resulted in higher content of triacylglycerols and n - 3 polyunsaturated fatty acids in the crude oil extracted.

Lipidomics in food quality and authentication: A comprehensive review of novel trends and applications using chromatographic and spectroscopic techniques

Lipid analysis is an integral part of food authentication and quality control which provides consumers with the necessary information to make an informed decision about their lipid intake. Recent advancement in lipid analysis and lipidome scope represents great opportunities for food science. In this review we provide a comprehensive overview of available tools for extraction, analysis and interpretation of data related to dietary fats analyses. Different analytical platforms are discussed including GC, MS, NMR, IR and UV with emphasis on their merits and limitations alongside complementary tools such as chemometric models and lipid-targeted online databases. Applications presented here include quality control, authentication of organic and delicacy food, tracing dietary fat source and investigating the effect of heat/storage on lipids. A multitude of analytical methods with different sensitivity, affordability, reproducibility and ease of operation are now available to comprehensively analyze dietary fats. Application of these methods range from studies which favor the use of large data generating platforms such as MS-based methods, to routine quality control which demands easy to use affordable equipment as TLC and IR. Hence, this review provides a navigation tool for food scientists to help develop an optimal protocol for their future lipid analysis quest.

Effect of packaging and encapsulation on the oxidative and sensory stability of omega-3 supplements

Omega-3 fatty acid consumption is getting more common due to its positive impacts on human health. Since consumers cannot get their omega-3 needs from natural sources, omega-3-rich products play an essential part in the diet. However, they are highly susceptible to oxidation; thus, storage conditions affect their quality. Product form is also another critical factor for stability. In this study, fatty acid composition, oxidative stability, and sensory properties of different omega-3 products having varied packaging types were investigated. Moreover, the effect of consumer behavior regarding the recommended usage was assessed during storage. Syrup forms (maximum values at the end of the storage: PV = 44.6 meq/kg oil for S32, p-AV = 16.87 for S22, and TOTOX = 96.94 for S11) are more susceptible to oxidation than capsule (maximum values at the end of the storage: PV = 7.62 meq/kg oil for C31, p-AV = 19.58 for C12, and TOTOX = 30.44 for C12) and chewable forms (maximum values at the end of the storage: PV = 26.14 meq/kg oil for G12, p-AV = 13.47 for G12, and TOTOX = 65.76 for G12). In addition, capsules complied more with limit values during storage and were better protected according to the sensory scores. The aroma and taste of the omega-3 products generally changed in a negative manner during storage. Capsulated samples were better protected according to the sensory evaluation scores at the end of the storage period. Fish oil samples belonging to the same company but provided from different stores showed significant differences, which is an indicator of nonstandard raw material, ingredient, or processing.

Effect of Flaxseed Addition on the Quality and Storage Stability of Sesame Paste

The flaxseed-sesame paste (FSP) was prepared by mixing the heat-treated flaxseed and sesame seeds in different proportions and grinding them in a colloid mill to obtain a FSP. In this study, flaxseed was added to sesame paste (SP) at different addition to assess its effect on the rheological properties, textural properties, and particle size. The effect of flaxseed addition on lipid oxidation and volatile aldehydes and ketones during storage of SP was investigated by accelerated oxidation experiments (63°C, 60 days). Notably, the addition of all different additions of flaxseed increased the linolenic acid content, and also enhanced the hardness, cohesiveness, and viscosity of SP. However, it increased the rate of lipid oxidation in SP during storage, mainly in the form of higher acid value (AV) and malondialdehyde (MDA) content. The content of volatile aldehydes and ketones from lipid oxidation increased significantly with storage time. It was found by using cluster analysis that mixing flaxseed with SP at a ratio of 20 g/100 g had little effect on its storage stability, the sample had a higher overall quality than the addition of 40 g/100 g flaxseed, and its linolenic acid content was 18.7 times higher than that of the SP. Collectively, the results indicated that the addition of flaxseed at an appropriate proportion might be a feasible way to prepare the functional formulated SP.

Quantitative analysis of fatty acids and vitamin E and total lipid profiling of dietary supplements from the German market

Certain polyunsaturated fatty acids with n-3 double bonds are essential nutrients for the human body and are part of the bilayer of cell membranes or precursors of tissue hormones. The most abundant dietary n-3 fatty acids in human nutrition are α-linolenic, eicosapentaenoic, and docosahexaenoic acid and can be taken up through dietary sources such as vegetable oils or fish or, alternatively, dietary supplements with high levels of n-3 fatty acids. In previous studies, considerable variation of lipid patterns and quantities of n-3 fatty acids were observed. In this study, 33 dietary supplements from the German market, based on fish-, krill-, microalgae, and plant oil, have been analyzed. Lipid profiling (LC–MS) revealed triacylglycerols as the dominant lipid species in most samples. However, krill oil was rich in phospholipids and samples containing fatty acid concentrates featured abundant fatty acid ethyl esters and diacylglycerols. Furthermore, total lipid profiles showed considerable variance depending on the lipid sources (e.g., fish or plant oil), which was also apparent in fatty acid analysis. The contents of n-3 fatty acids ranged between 150 and 570 mg/g capsule content (GC–MS) and vitamin E (α-tocopherol and tocopheryl acetate) were found in quantities ranging from 1.2 to 86.1 mg/g capsule content (HPLC–UV/Vis). While our analyses indicated a good agreement between labeled and present quantities of total n-3 fatty acids and vitamin E for the majority of samples, significant differences in agreement between individual fatty acids were observed, as well as frequent mismatches between declared and present vitamin E derivatives.

Mechanism of the initial oxidation of monounsaturated fatty acids

The development of detection technology prompts the need to elaborate on the theory behind the oxidation of unsaturated fatty acids. This study integrates the detection of monounsaturated fatty acid oxidation at 60 °C with computational simulations to provide an advanced theoretical basis for the formation of hydroperoxides and allyl. The results indicate that oxidation reaction led to increases of 3.4 mg/g for 8-hydroperoxy-trans-9-octadecenoate (trans8) and 2.7 mg/g for 9-hydroperoxy-trans-10-octadecenoate (trans9) and 10-hydroperoxy-trans-8-octadecenoate (trans10) despite low temperatures. The energy of peroxyl radical production was 0.36 kcal/mol and that of allylic isomerization was 78.52 kcal/mol, indicating the existence of two pathways for hydroperoxides formation: β-fragmentation and the allylic isomerization. Structural equation modeling (SEM) verified the multistep competitive side reactions that occurred during oxidation. This finding provides a new basis for future analysis of lipid oxidation.

Toxicity of oxidized fish oil in pregnancy - a dose response study in rats

INTRODUCTION

Fish oil (FO) supplements are consumed during pregnancy to increase dietary omega-3. However, FO is often oxidized past recommended limits. In rats, a large dose of highly oxidized FO substantially increased newborn mortality, but the effects of human-relevant doses of less oxidized oil are unknown. A dose-response study in rats was conducted to estimate the safe level of oxidation during pregnancy.

METHODOLOGY

Sprague-Dawley rat dams were mated, then individually housed and provided with a gel treatment on each day of pregnancy. Treatment groups differed only in the FO content of the gel; control (no oil), PV5, PV10, and PV40 (0.05ml of FO oxidized to a peroxide value (PV) of 5, 10, or 40meq/kg), or PV40(1ml) (1ml of PV40). A subset of dams was culled on gestational day 20 to enable sampling, and the remainder were allowed to give birth. Newborn mortality was recorded. Offspring were sampled at postnatal days 2 and 21, and dams at day 21.

RESULTS

There were no signs of unwellness during pregnancy. However, there was markedly increased neonatal mortality affecting the PV40(1ml) (12.8%) and PV40 (6.3%) groups, but not the control, PV5, or PV10 groups (1-1.4%). Dietary oxidized FO altered the expression of placental genes involved in antioxidant pathways and the production of free radicals. Conclusions Highly oxidized FO was toxic in rat pregnancy leading to a marked increase in mortality even at a human-relevant dose. We observed no toxic effects of FOs with PV≤ 10meq/kg, suggesting that this is an appropriate maximum limit.

Food Fortification Using Spray-Dried Emulsions of Fish Oil Produced with Maltodextrin, Plant and Whey Proteins-Effect on Sensory Perception, Volatiles and Storage Stability

Fortification of foods with fish oil rich in n–3 fatty acids improves the nutritional value, but creates challenges with flavor and oxidative stability, especially during storage. Pea, soy, and sunflower proteins were used in combination with whey protein or maltodextrin to encapsulate fish oil by spray-drying. The use of whey protein compared with maltodextrin as wall material improved oxidative stability of spray-dried emulsions, although the use of whey protein increased the number of observed cracks in outer shell of the particles. Non- and encapsulated oil were used in cookies and chocolates to examine flavor characteristics by generic descriptive analysis and volatile products by solid-phase microextraction with gas chromatography-mass spectrometry. A long-term storage test at room temperature was conducted to evaluate the oxidative stability of the food models. Fortification changed the texture, odor, and flavor of the food models with fishy flavor being the most impactful attribute. For both food models, use of pea protein with maltodextrin resembled attributes of control the best. Fortification and encapsulation material also affected volatile profiles of food models. Both non-encapsulated oil and whey protein formulations performed well in regard to oxidative stability for both food models. Generally, the cookie model showed more potential for fortification than the chocolate one.

Similarity Index for the Fat Fraction between Breast Milk and Infant Formulas

The similarity of the fat fraction in infant formulas rich in either bovine milk fat (MF) or vegetable oil (VO) to breast milk was evaluated by analyzing their lipid composition. Milk fat-rich formulas were highly similar (average similarity index 0.68) to breast milk compared to the VO-rich formulas (average similarity index 0.56). The highest difference in the indices was found in the contents of cholesterol (0.66 vs 0.28 in MF- and VO-rich formulas, respectively, on average) and polar lipids (0.84 vs 0.53), the positional distribution of fatty acids in the sn-2 position of triacylglycerols (0.53 vs 0.28), and fatty acid composition (0.72 vs 0.54). The VO-based formulas were superior in similarity in n - 6 PUFA. Thus, the addition of bovine MF fractions is an effective way to increase the similarity between the lipid composition of infant formulas and human milk.

Comprehensive Analysis of Fatty Acid and Oxylipin Patterns in n3-PUFA Supplements

Supplementing long-chain omega-3 polyunsaturated fatty acids (n3-PUFA) improves health. We characterized the pattern of total and non-esterified oxylipins and fatty acids in n3 supplements made of fish, krill, or micro-algae oil by LC-MS. All supplements contained the declared amount of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA); however, their content per capsule and the concentration of other fatty acids varied strongly. Krill oil contained the highest total n3 oxylipin concentration (6000 nmol/g) and the highest degree of oxidation (EPA 0.7%; DHA 1.3%), while micro-algae oil (Schizochytrium sp.) showed the lowest oxidation (<0.09%). These oils contain specifically high amounts of the terminal hydroxylation product of EPA (20-HEPE, 300 nmol/g) and DHA (22-HDHA, 200 nmol/g), which can serve as an authenticity marker for micro-algae oil. Refined micro-algae and fish oil were characterized by NEFA levels of ≤0.1%. Overall, the oxylipin and fatty acid pattern allows gaining new insights into the origin and quality of n3-PUFA oils in supplements.

Quality of Protein Isolates and Hydrolysates from Baltic Herring (Clupea harengus membras) and Roach (Rutilus rutilus) Produced by pH-Shift Processes and Enzymatic Hydrolysis

Fractionation is a potential way to valorize under-utilized fishes, but the quality of the resulting fractions is crucial in terms of their applicability. The aim of this work was to study the quality of protein isolates and hydrolysates extracted from roach (Rutilus rutilus) and Baltic herring (Clupea harengus membras) using either pH shift or enzymatic hydrolysis. The amino acid composition of protein isolates and hydrolysates mostly complied with the nutritional requirements for adults, but protein isolates produced using pH shift showed higher essential to non-essential amino acid ratios compared with enzymatically produced hydrolysates, 0.84–0.85 vs. 0.65–0.70, respectively. Enzymatically produced protein hydrolysates had a lower total lipid content, lower proportion of phospholipids, and exhibited lower degrees of protein and lipid oxidation compared with pH-shift-produced isolates. These findings suggest enzymatic hydrolysis to be more promising from a lipid oxidation perspective while the pH-shift method ranked higher from a nutrient perspective. However, due to the different applications of protein isolates and hydrolysates produced using pH shift or enzymatic hydrolysis, respectively, the further optimization of both studied methods is recommended.

Transcriptomics and metabolomics analysis reveal the anti-oxidation and immune boosting effects of mulberry leaves in growing mutton sheep

Introduction

Currently, the anti-oxidation of active ingredients in mulberry leaves (MLs) and their forage utilization is receiving increasing attention. Here, we propose that MLs supplementation improves oxidative resistance and immunity.

Methods

We conducted a trial including three groups of growing mutton sheep, each receiving fermented mulberry leaves (FMLs) feeding, dried mulberry leaves (DMLs) feeding or normal control feeding without MLs.

Results

Transcriptomic and metabolomic analyses revealed that promoting anti-oxidation and enhancing disease resistance of MLs is attributed to improved tryptophan metabolic pathways and reduced peroxidation of polyunsaturated fatty acids (PUFAs). Furthermore, immunity was markedly increased after FMLs treatment by regulating glycolysis and mannose-6-phosphate pathways. Additionally, there was better average daily gain in the MLs treatment groups.

Conclusion

These findings provide new insights for understanding the beneficial effects of MLs in animal husbandry and provide a theoretical support for extensive application of MLs in improving nutrition and health care values.

Comparative assessment of the effect of pretreatment with microwave and roast heating on the quality of black sesame pastes

Heating is a key procedure in producing sesame paste. The effects of microwave heating and conventional roasting on the physicochemical features, protein profiles, and volatile compounds of black sesame pastes made of black sesame seeds from Burma and China were evaluated in this study. All heating treatments decreased the moisture contents of black sesame pastes, and roasting yielded lower moisture levels, although with similar chroma (p < 0.05). The samples subjected to microwave heating had remarkably lower peroxide values than those heated with roasting (p < 0.05). Chinese microwave-heated samples had a higher nitrogen solubility index than roasting (p < 0.05). Both microwave and roasting increased the contents of the volatiles notably. SDS-PAGE showed that the intensity of the 2-15 kDa band decreased markedly after heating and nearly diminished for roasting samples, suggesting that roasting was more remarkable for the promotion to the protein aggregation. The results indicated that the quality traits of black sesame paste not only depend on the heating methods, but also the heating power/temperature and duration, and the source of the materials.

Quality of Fish-Oil-Based Dietary Supplements Available on the Italian Market: A Preliminary Study

The global market of food supplements is growing rapidly with a large turnover. Fish oil supplements represent a significant part of this turnover as they are believed to have important health benefits. Conversely, there are few papers in the literature about the quality control of fish oil capsules. As prior studies illustrate, a perfect agreement with the label is rarely found, and in some isolated cases, large amounts of soybean oil are also detected, indicating a true adulteration rather than a non-compliance with the label. None of the available studies refer to the Italian market, which ranks first in Europe in the consumption of food supplements. In this present communication, a quality control of fish-oil-based supplements from the Italian market was carried out for the first time. With minor deviations, all results showed substantial agreement with the label. However, the most important conclusion from this research is that compliance with the label is not enough to judge a product of good quality. The analysis of the overall fatty acid composition showed that some supplements have a high level of saturated fatty acids, and therefore they did not undergo a proper purification process. This may represent a safety issue since the purification process also allows the removal of toxic contaminants.

Enzyme-Assisted Extraction of Fish Oil from Whole Fish and by-Products of Baltic Herring (Clupea harengus membras)

Baltic herring (Clupea harengus membras) is one of the most abundant commercially caught fish species from the Baltic Sea. Despite the high content of fat and omega-3 fatty acids, the consumption of Baltic herring has decreased dramatically over the last four decades, mostly due to the small sizes and difficulty in processing. At the same time there is an increasing global demand for fish and fish oil rich in omega-3 fatty acids. This study aimed to investigate enzyme-assisted oil extraction as an environmentally friendly process for valorizing the underutilized fish species and by-products to high quality fish oil for human consumption. Three different commercially available proteolytic enzymes (Alcalase^®, Neutrase^® and Protamex^®) and two treatment times (35 and 70 min) were investigated in the extraction of fish oil from whole fish and by-products from filleting of Baltic herring. The oil quality and stability were studied with peroxide- and p-anisidine value analyses, fatty acid analysis with GC-FID, and volatile compounds with HS-SPME-GC-MS. Overall, longer extraction times led to better oil yields but also increased oxidation of the oil. For whole fish, the highest oil yields were from the 70-min extractions with Neutrase and Protamex. Protamex extraction with 35 min resulted in the best fatty acid composition with the highest content of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) but also increased oxidation compared to treatment with other enzymes. For by-products, the highest oil yield was obtained from the 70-min extraction with Protamex without significant differences in EPA and DHA contents among the oils extracted with different enzymes. Oxidation was lowest in the oil produced with 35-min treatment using Neutrase and Protamex. This study showed the potential of using proteolytic enzymes in the extraction of crude oil from Baltic herring and its by-products. However, further research is needed to optimize enzymatic processing of Baltic herring and its by-products to improve yield and quality of crude oil.

Letter to the editor regarding "Omega-3 fats in pregnancy: could a targeted approach lead to better metabolic health for children?"

The purpose of our letter to the editor is to offer additional perspective regarding 4 statements that do not fully represent the totality of the available scientific evidence. The 4 statements are as follows: (1) "Multiple studies have shown that n-3 PUFA products frequently have less n-3 PUFA content than labelled"; (2) "Recently, krill oil supplementation was shown to induce insulin resistance, indicating that it is potentially harmful"; (3) "… fish oil products are frequently oxidized at the time of purchase"; and (4) "In rats, supplementation with oxidized fish oil during pregnancy induced persistent maternal insulin resistance and increased neonatal mortality rate." We respectfully request the authors' future publications consider the totality of the available scientific evidence.

Response to Bannenburg and Rice

This manuscript is a response to concerns expressed in a letter by industry-based scientists Bannenburg and Rice in response to our recent narrative review. In the review, we largely discussed why supplementation with n-3 PUFA rich oils might have benefits to the body composition and metabolism of the offspring of overweight or obese pregnant women. Bannenburg and Rice raised concerns about a number of points that may be perceived as negative about the quality and functionality of commercial fish oils. We provide a refutation to their comments and a brief review of recent evidence regarding the n-3 PUFA content, and oxidative state of supplements available to consumers. From a clinical research perspective, there remains a need to exercise caution. An oil containing less n-3 PUFAs than expected may be ineffective, and lead to incorrect conclusions that n-3 PUFAs lack efficacy. Oxidized fish oil may be ineffective or even cause unwanted harm. Although we must not overinterpret limited evidence from animal models, we have a responsibility to minimize risk to study participants, especially those most vulnerable, such as pregnant women. Prior to selecting a fish oil to be used in a clinical trial, it is essential to independently verify the n-3 PUFA content of the oil, and that the oil is unoxidized.

Chemical Compositional Changes in Over-Oxidized Fish Oils

A recent study has reported that the administration during gestation of a highly rancid hoki liver oil, obtained by oxidation through sustained exposure to oxygen gas and incident light for 30 days, causes newborn mortality in rats. This effect was attributed to lipid hydroperoxides formed in the omega-3 long-chain polyunsaturated fatty acid-rich oil, while other chemical changes in the damaged oil were overlooked. In the present study, the oxidation condition employed to damage the hoki liver oil was replicated, and the extreme rancidity was confirmed. A detailed analysis of temporal chemical changes resulting from the sustained oxidative challenge involved measures of eicosapentaenoic acid/docosahexaenoic acid (EPA/DHA) omega-3 oil oxidative quality (peroxide value, para-anisidine value, total oxidation number, acid value, oligomers, antioxidant content, and induction time) as well as changes in fatty acid content, volatiles, isoprostanoids, and oxysterols. The chemical description was extended to refined anchovy oil, which is a more representative ingredient oil used in omega-3 finished products. The present study also analyzed the effects of a different oxidation method involving thermal exposure in the dark in contact with air, which is an oxidation condition that is more relevant to retail products. The two oils had different susceptibility to the oxidation conditions, resulting in distinct chemical oxidation signatures that were determined primarily by antioxidant protection as well as specific methodological aspects of the applied oxidative conditions. Unique isoprostanoids and oxysterols were formed in the over-oxidized fish oils, which are discussed in light of their potential biological activities.