Manipulation of Omega‐3 PUFAs in Lamb: Phenotypic and Genotypic Views

A number of studies have shown that dietary omega‐6 and omega‐3 long‐chain fatty acids can be incorporated into muscle tissue of ruminants despite the biohydrogenation of dietary fatty acids in the rumen. The main focus of this review is on eicosapentaenoic (20:5n‐3) and docosahexaenoic (22:6n‐3) fatty acids because health authorities around the world consider the sum of these fatty acids as the basis of classifying a food as a source or good source of omega‐3 polyunsaturated fatty acids (PUFAs). A high proportion of polyunsaturated fatty acids are hydrogenated in the rumen, leading to a higher concentration of 18:0, but some escapes the rumen to be absorbed intact by the small intestine. Feeding strategies for ruminants have been successfully applied to increase the absorption of PUFAs in the small intestine and therefore to increase the levels of PUFAs in muscle tissue. Protected fats and algae are strong candidates to improve the nutritional value of red meat in ruminants in terms of health‐claimable omega‐3 fatty acids. Efforts to understand the genetic basis of fatty acid metabolism have been underway. The knowledge of the main genes which control the output of omega‐3 fatty acids is still lacking, but gene expression studies have helped to explain the deposition of these acids in muscle, liver, and subcutaneous fat.     

Optimising drying parameters to maximise omega‐3 essential fatty acid yields in striped weakfish (Cynoscion striatus) industry waste

Fish processing produces high amounts of wastes with low commercial value. Nevertheless, this material could be valorised through the extraction of its polyunsaturated fatty acids. Therefore, the purpose of this study was to evaluate the drying process of striped weakfish (Cynoscion striatus) waste in an air‐circulating oven, aiming to preserve the omega‐3 content. The microbiological and chemical characteristics of the dried product were evaluated. In addition, the lipid quality of the Soxhlet‐extracted oil from the dried material was analysed. The drying condition of 70 °C and 10 h was the most suitable, because it preserved 98.7% of the original content of omega‐3. The dry material presented 14.7% of lipids and 58% of protein, and it was microbiologically safe. The Soxhlet extraction, in spite of using high temperature, did not promote the oxidation of polyunsaturated acids. The applied drying process, followed by Soxhlet extraction, yielded 7.6 g of omega‐3 fatty acids per kg of fresh sample. These results indicate that this residue presents large potential for oil extraction.     

Comparison of Polyunsaturated Fatty Acids Content in Filets of Anadromous and Landlocked Sockeye Salmon Oncorhynchus Nerka

Abstract: Fatty acid composition and content of 2 forms of sockeye salmon Oncorhynchus nerka from lakes in Kamchatka Peninsula (Russia) were compared. One form of sockeye salmon was anadromous (“marine”), that is, adult fish migrated in ocean to feed and grow and than return in the lake to breed. Fish of another form, kokanee, never migrate in the ocean. Per cent levels of the main indicators of nutritive value, eicosapentaenoic acid (EPA, 20:5n‐3), and docosahexaenoic acid (DHA, 22:6n‐3), were significantly higher in the landlocked O. nerka. However, concentrations of EPA and DHA per wet weight of filets were higher in the marine form, because of the relatively higher content of sum of fatty acids in their muscle tissue. As concluded, fish fed in marine environment had higher contents of long‐chain n‐3 fatty acids per wet weight than fish of the same species, fed in fresh waters. In general, both the anadromous sockeye salmon and the landlocked kokanee salmon can be recommended for human diet as a valuable product concerning contents of EPA and DHA. Practical Application: The long‐chain polyunsaturated acids (PUFA) have been specifically recommended for humans to prevent cardiovascular disease and psychiatric disorders. Fish are known to be the main source of PUFA in human diet. Data on PUFA content in diverse food fish is essential to compare the benefits they offer for consumers’ health. We compared PUFA contents in 2 forms of popular food fish Oncorhynchus nerka, migrating sockeye salmon and landlocked kokanee salmon, and found that both forms are valuable product concerning PUFA content.     

Frying of potato chips in a blend of canola oil and palm olein: changes in levels of individual fatty acids and tocols

The changes occurring in the levels of nutritionally relevant oil components were assessed during repeated frying of potato chips in a blend of palm olein and canola oil (1:1 w/w). The blend suffered minimal reductions in omega‐3 and omega‐6 polyunsaturated fatty acids. There was no significant difference between the fatty acid composition of the oil extracted from the product and that of the frying medium, in all three cases. The blend also contained a significant amount of tocols which add a nutritional value to the oil. The concentration of the tocols was satisfactorily retained over the period of oil usage, in contrast to the significant loses observed in the case of the individual oils. The blend also performed well when assessed by changes in total polar compounds, free fatty acids, p‐anisidine value. When fried in used oil, the product oil content increased progressively with oil usage time. This study shows that blended frying oils can combine good stability and nutritional quality.     

The bioavailability of an omega‐3‐rich algal oil is improved by nanoemulsion technology using yogurt as a food vehicle

Global trends show that habitual omega‐3 intakes are short of recommended guidelines, particularly among vegetarians. Subsequently, alternative dietary sources of long‐chain omega‐3 polyunsaturated fatty acids (LC3PUFA) from vegetarian sources are needed. Food technology methods are advancing, and nanoemulsion technologies have improved the bioavailability of certain lipid‐based nutrients. This study examined whether ingestion of an omega‐3 algal oil nanoemulsion led to improved bioavailability compared to the bulk oil. Eleven subjects completed a single‐blind, randomised crossover trial, with a 21‐day washout between interventions. Results demonstrated that LC3PUFA absorption from the nanoemulsion was significantly higher than the bulk oil. Percentage blood fatty acids were significantly increased for docosahexaenoic acid (DHA; P ≤ 0.05) while LC3PUFA: PUFA ratios increased (P ≤ 0.05) and omega‐6:omega‐3 ratios were reduced (P = 0.028). Larger and longer intervention studies are now needed, but these preliminary findings demonstrate that nanoemulsion technology may improve the absorption of omega‐3 fatty acids.     

Repeated hydrolysis process is effective for enrichment of omega 3 polyunsaturated fatty acids in salmon oil by Candida rugosa lipase

Enrichment of omega 3 polyunsaturated fatty acids (PUFA) in the glyceride fraction of salmon oil was performed by Candida rugosa lipase (CRL)-catalysed hydrolysis. Total omega 3 PUFA content in the product was 38.71% (mol.%), more than double of the initial level. The hydrolysis reaction was scaled up to 1 l in a stirred tank reactor without any decrease in the selectivity of the reaction. Moreover, non-steroselectivity and acyl chain specificity of CRL-catalysed hydrolysis, as well as CRL’s recognition of the whole triacylglycerol molecule, were proved. The product was purified by short path distillation, which was also shown to contribute to the recovery of omega 3 PUFA in residue. After the removal of free fatty acids, the final product was subjected to a second round of hydrolysis to concentrate omega 3 PUFA further to 50.58%. Recoveries of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) decreased slightly after the second round of hydrolysis, while oleic acid (OA) content was not affected.     

A quantitative and qualitative assessment of mung bean (Vigna mungo (L.) Wilczek) seed in response to elevated atmospheric carbon dioxide: potential changes in fatty acid composition

The effect of rising atmospheric carbon dioxide concentration ([CO₂]) on seed production and the fatty acid profiles of mung bean (Vigna mungo L. Wilczek) were studied under field conditions. Increased [CO₂] (ca 250 ppm above ambient) resulted in significant increases in pod number, pod weight and total seed weight, but also significantly increased the percentage of immature pods at harvest. Qualitatively, increased [CO₂] significantly decreased the percentages of palmitic and omega‐6 fatty acids, but increased the percentage of omega‐3 fatty acids and the relative proportion of omega‐3 to omega‐6 fatty acids in mature seed. Overall, increased carbon dioxide may significantly increase quantity and alter quality in mung bean seed, a recognized alternative source of fatty acids in the human diet. Copyright © 2007 Society of Chemical Industry     

Utilization of smoked salmon trim in extruded smoked salmon jerky

During smoked salmon processing, the dark meat along the lateral line is removed before packaging; this by-product currently has little economic value. In this study, the dark meat trim was incorporated into an extruded jerky. Three formulations were processed: 100% smoked trim, 75% : 25% smoked trim : fresh salmon fillet, and 50% : 50% smoked trim : fresh salmon blends (w/w basis). The base formulation contained salmon (approximately 83.5%), tapioca starch (8%), pregelatinized potato starch (3%), sucrose (4%), salt (1.5%), sodium nitrate (0.02%), and ascorbyl palmitate (0.02% of the lipid content). Blends were extruded in a laboratory-scale twin-screw extruder and then hot-smoked for 5 h. There were no significant differences among formulations in moisture, water activity, and pH. Protein was highest in the 50 : 50 blend jerky. Ash content was highest in the jerky made with 100% trim. Total lipids and salt were higher in the 100% trim jerky than in the 50 : 50 blend. Hot smoking did not adversely affect docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) content in lipids from 100% smoked trim jerky. Servings of salmon jerky made with 75% and 100% smoked trim provided at least 500 mg of EPA and DHA. The 50 : 50 formulation had the highest Intl. Commission on Illumination (CIE) L*, a*, and b* color values. Seventy consumers rated all sensory attributes as between "like slightly" and "like moderately." With some formulation and processing refinements, lateral line trim from smoked salmon processors has potential to be incorporated into acceptable, healthful snack products. PRACTICAL APPLICATION: Dark meat along the lateral line is typically discarded by smoked salmon processors. This omega-3 fatty acid rich by-product can be used to make a smoked salmon jerky that provides a convenient source of these healthful lipids for consumers.     

Cheese fortification using saturated monoglyceride self‐assembly structures as carrier of omega‐3 fatty acids

The purpose of this research was to study the capacity of emulsions containing saturated monoglyceride self‐assembly structures to deliver omega‐3 fatty acids in fresh soft cheese. To this aim, fortified emulsions containing different ratios of milk, saturated monoglycerides (MGs) and cod liver oil were added to milk before cheese‐making. These emulsions were characterised by distinct microstructural features observed by polarised light microscopy and apparent viscosity values. The omega‐3 delivery performance of MG emulsions highlighted that this strategy allowed a good retention of the omega‐3‐rich oil in the curd (up to 75%). The fortified cheeses showed yield value and fat content higher than those of control samples. The enriched cheese showed hardness and cohesiveness obtained by texture profile analysis similar to those of the unfortified product. Only a slight decrease in gumminess was detected in fortified cheese.     

发酵牛肉干加工中理化特性与风味品质分析

为探究发酵牛肉干不同加工阶段理化性质和风味品质的变化,以牛臀肉为原料,接种木糖葡萄球菌和清酒乳杆菌制作发酵牛肉干,并对牛肉干在发酵前后及成品的营养成分、质构、色泽等理化特性及游离氨基酸、脂肪酸组成和挥发性风味物质对比分析。结果表明,与发酵前相比,接种复合发酵剂的牛肉干pH值、水分活度、亚硝酸盐残留量、硬度、咀嚼性均显著降低（P＜0.05）;红度值和游离氨基酸含量显著增加,且鲜味氨基酸占比最高;游离脂肪酸以棕榈酸、硬脂酸、油酸、亚油酸为主,其中油酸占比最大;发酵后牛肉检出47 种挥发性化合物,高于发酵前42 种,提高了牛肉干中醛、醇、酚、酯、酸、含氮及其他化合物的种类和相对含量。发酵牛肉干质构及色泽明显改善,游离氨基酸和脂肪酸含量增加,产品营养价值、风味品质及质量安全显著提高。     

Optimization of pork jerky fermentation with Lactobacillus bulgaricus

Lactobacillus bulgaricus was used to ferment raw pork to pork jerky at different fermentation conditions, including temperature, initial pH value, and time. Through assessing the sensory attributes, the free amino acids, and pH of the pork jerky, it was determined that the optimum conditions for fermentation was temperature of 35 °C, initial pH of 6.5, and fermentation time of 36 hr. Through fermenting with L. bulgaricus, the texture, the color, and the flavor of the prepared pork jerky were improved. The pH of pork jerky was lower than fresh pork which thus, potentially enhanced the safety of pork jerky. Additionally, the free amino acids contents of pork jerky were higher (greater than 143.5 mg/100 g) than the fresh pork (64.0 mg/100 g) which suggest more benefits and better absorption. The results presented herein demonstrate that the L. bulgaricus can be used for the production of fermented pork jerky to improve the quality attributes and the safety of pork jerky.

Practical applications

Pork jerky is a traditional food in China. It is popular because it is tasty and easy to carry. Microbial fermentation technology was applied to the production process of the pork jerky, which can change the traditional dried meat product quality and processing technology that change little for years. The fermented pork jerky not only improves the flavor of pork jerky, also improve its security. Therefore, the fermented pork jerky can overcome the defects of traditional process, such as hard palate, off‐color, and preservative addition.     

Characterisation of yoghurt enriched with polyunsaturated fatty acids by using walnut slurry

This study aimed to evaluate the physicochemical, chemical, rheological, sensorial and microbiological properties of yoghurt enriched with polyunsaturated fatty acids (PUFAs). The PUFA‐enriched yoghurt was prepared with walnut slurry (10%?50%) and skimmed milk (50%?90%). Compared with the control yoghurt, it contained a lower content of protein, potassium, sodium and phosphorus, and a higher content of fat, iron, magnesium and zinc. Moreover, it exhibited a lower syneresis value and a higher water‐holding capacity value. Its fat was rich in omega fatty acids, mainly linoleic and linolenic acids. These research findings revealed that walnut slurry could be used in yoghurt manufacture to develop fermented milk products as functional foods, especially when enriched with omega fatty acids.     

Effect of Fish and Oil Nature on Frying Process and Nutritional Product Quality

ABSTRACT: The modifications on a lean fish (cod—Gadus morhua) and a fatty fish (farmed salmon—Salmo salar) after the application of pan-frying using 2 types of oil with different lipid profile (extra virgin olive oil and sunflower oil) was the aim of this study. Fat content and total energetic value increased significantly after the frying process only in the lean fish, without relevant changes in the fatty fish. Extra virgin olive oil led to a higher fat absorption rate than sunflower oil in both fish. Frying hardly affected the lipid profile of farmed salmon regardless the oil used, however it drastically changed in fried cod compared to raw cod. Omega-6/omega-3 ratio increased from 0.08 in raw cod to 1.01 and 6.63 in fried cod with olive oil and sunflower oil, respectively. In farmed salmon, the omega-6/omega-3 ratio was 0.38 (raw), and 0.39 to 0.58 in fried salmon. The amount of EPA + DHA slightly decreased with frying in salmon, and increased in cod. The type of oil has more influence in the nutritional fish quality for the lean fish compared to that of the fatty fish. The use of extra virgin olive oil was efficient to avoid a significant increase of the lipid oxidation intensity during frying in cod but not in salmon. Practical Application: Food modifies its composition and nutritional value with the application of cooking technologies. As most food table composition tables are based on raw food products, this article contributes with interesting data on pan-fried fish composition, which may improve the approach to achieve a real intake of healthy nutrients as omega 3 fatty acids.     

Fatty acids distribution in different tissues of wild and reared Seriola dumerili

In this study, we compared the lipid and fatty acids content, between cultured and wild Seriola dumerili, in different edible portions. Results showed that cultured fish contained a higher level of lipids than wild fish. The fatty acids profiles revealed that, among all the split‐fish side, palmitic (C16:0) and oleic (C18:1n‐9) acid were the principal saturated and monounsaturated fatty acids, in cultured and wild S. dumerili. On the other hand, wild S. dumerili contained a higher level of saturated (38.12 ± 0.54% vs. 33.66 ± 0.15% in cultured fish), monounsaturated (33.13 ± 1.07% vs. 26.49 ± 0.17%), n‐3 polyunsaturated fatty acids (PUFA) (23.90 ± 1.02% vs. 19.77 ± 0.51%) particularly docosahexaenoic acid (DHA) (18.83 ± 0.48% vs. 11.77 ± 0.42%). However, the cultured fish showed a higher level of n‐6 PUFA due principally to the higher value of linoleic acid (C18:2n‐6). In fact, changes in fatty acids content between anatomical areas marked differences in the muscle quality of wild and cultured S. dumerili. According to this study, both groups of wild and farmed S. dumerili have nutritional benefits for human health. Cultured fish were characterised by higher hypocholesterolaemic and hypercholesterolaemic fatty acids ratio for all samples studied and a lower n‐3/n‐6 ratio due to the abundance of n‐3 PUFA particularly DHA in wild fish.     

Lipid fraction quality of milk produced by Minhota (Portuguese autochthonous breed) compared to Holstein Friesian cow's

BACKGROUND: Minhota and Holstein Friesian cows (15 from each breed) were selected from several farms located in the north of Portugal, all under similar feeding regime. Milk samples from individual cows were collected once a month, during one year, to take into account different lactation stages and feeding seasonal changes. RESULTS: Holstein milk was found to have higher content of total polyunsaturated fatty acids, omega‐6, and trans fatty acids, while Minhota milk had significantly higher monounsaturated fatty acids content. No statistical differences were observed for omega‐3 and saturated fatty acids contents, mostly due to the high dispersion observed in Minhota milk samples. The average amount of conjugated linoleic acid was higher in Minhota breed, but the high dispersion of values reduced the statistical significance. Cholesterol content, expressed as mg kg^?1 of fat, was higher in Holstein than in Minhota milk. CONCLUSION: The results indicate that Minhota milk has important nutritional qualities that deserve attention, but the wide individual variation found within animals from this breed suggests a high genetic variability. Following this, the selection of some of these animals for intensive milk production could improve milk quality. Copyright © 2012 Society of Chemical Industry     

Curing properties of sodium nitrite in restructured goat meat (chevon) jerky

Known curing impacts on goat meat (chevon) is limited due to the low production and consumption of chevon products in the United States. This study, therefore, assessed sodium nitrite influences on the quality parameters of restructured chevon jerky and its stability. Inclusion of NaNO₂ increased (p < 0.01) the redness of chevon jerky (14.2 versus 8.17); however, the redness was decreased (p < 0.01) over a 30 d storage period. The texture properties and microbial counts of jerky were not influenced by NaNO₂. However, the total microbial counts increased (1.84 to 6.00 ± 0.468 log CFU/g; p < 0.01) with storage time in chevon jerky whether or not nitrite was included. Inclusion of NaNO₂ decreased (p < 0.05) thiobarbituric acid reactive substances values (4.26 versus 4.81 mg MDA/kg), which did not change during storage. Among 28 isolated fatty acids from chevon jerky, palmitic (C16:0), stearic (C18:0), oleic (C18:1n9), and linoleic (C18:2n6) acids were the major four fatty acids. Of the 21 positively identified volatile compounds, six terpenes (α-pinene, β-pinene, β-phellandrene, carene, limonene, and cubebene), octanone and nonanal were the most abundant compounds. Neither processing treatment nor storage time significantly influenced the concentration of individual fatty acids and volatile compounds. Cured jerky had higher (p < 0.05) sensory color and flavor scores compared to uncured jerky. Results indicated that inclusion of NaNO₂ might improve color and sensory properties, as well as control the lipid oxidation of chevon jerky. However, the reduction of lipid oxidation in jerky was not revealed in product fatty acid or volatile flavor compounds.     

Comparison of Nutritional Composition,Aroma Compounds,and Biological Activities of Two Kinds of Tartary Buckwheat Tea

Tartary buckwheat tea (TBT) is becoming increasingly popular for its unique flavor and health benefits. However, there is little information regarding the differences in nutritional quality among different kinds of TBT. Two kinds of TBT samples, whole grain tea (WGT) and whole plant tea (WPT), were collected from markets in China. The content of their nutritional compositions, including protein, amino acids, starch, fat, fatty acids, and flavonoids, as well as aroma compounds, were determined. Antioxidant and α‐glucosidase inhibitory activities were also evaluated. WPT showed higher levels of protein and fat relative to WGT, but the content of essential amino acids and fatty acids was lower. WPT contained more total flavonoids with quercetin as the predominant flavonoid (81%), while rutin was the principal flavonoid compound (86%) in WGT. GC‐MS analysis indicated that there were some differences in the aroma compound profile between WGT and WPT, though 14 aroma compounds were identified in both of them with 3‐ethyl‐2,5‐dimethyl‐pyrazine as the predominant compound. In addition, WPT showed superior antioxidant and α‐glucosidase inhibitory activities than WGT. However, the total flavonoid content determined in tea soup was decreased by 60% and 98% compared with that in the alcohol extracts of WGT and WPT, respectively. The antioxidant and α‐glucosidase inhibitory activities of tea soup were also lowered, especially for WPT. The differences between 2 kinds of TBT might be due to the variety of raw materials and processing methods. Diversified plant materials and scientific processing technologies should be taken into account to develop a nutritional and healthy TBT product.     

Volatile compounds and oxidative stability of Pinus halepensis Mill. seed oil under heating conditions

Heating conditions of Pinus halepensis seed oil were monitored to evaluate the effect of thermo‐oxidation processes on the bioactive compounds contained in the samples. The following parameters were monitored: ultra violet absorption at 232 and 270 nm, fatty acid composition, oxidative stability, antiradical activity and aromatic profiles. Under thermo‐oxidation process, trans fatty acids (TFA) increased and conjugated linoleic acid isomers appeared. The antiradical activity significantly decreased from 73.3% to 52.5% after 120 min of heating. Oxidative stability decreased (r = ?0.70). The volatile profile was heavily influenced by heating with the formation of new volatile compounds, such as the two isomers (E,Z)‐2,4‐decadienal and (E,E)‐2,4‐decadienal. α‐pinene, and the main terpene compound was very vulnerable to heating conditions. Despite its peculiar pleasant aroma and nutritional value, the P. halepensis seed oil should not be used for cooking. Indeed, under frying conditions, its antioxidant properties and oxidative stability are lost and potential toxic compounds, such as TFA and unsaturated aldehydes, are formed.     

Portuguese bee pollen: palynological study,nutritional and microbiological evaluation

Bee pollen is one of the richest and purest natural foods, used in the folk medicine, clinical practices, and food and pharmaceutical industries. This work aims to characterise, for the first time in Portugal, the palynological origin, nutritional value and microbiological safety of this beehive product. It identified ten botanical families, and the more frequent were Boraginaceae and Ericaceae. We have evaluated the water content, a_w, pH, reducing sugars, ash, carbohydrate, proteins, lipids, fatty acids and energy. The microorganisms studied were the aerobic mesophiles, moulds and yeasts, faecal coliforms, Escherichia coli, Staphylococcus aureus, Salmonella and sulphite‐reducing clostridia. The studied pollens are nutritionally well balanced, and contain high levels of moisture, proteins, fat, energy, ash, carbohydrates, reducing sugars, essential n‐3 fatty acids and good ratios of polyunsaturated fatty acids (PUFA)/saturated fatty acids. In fact, the PUFA represent 66% of the total fatty acids. The samples had good microbiological quality, as none of the samples had toxigenic species.