Farmed meagre,Argyrosomus regius of three different sizes: what are the differences in flesh quality and muscle cellularity?

Larger meagre are more common in the market but, recently, smaller fish have started to be commercialised as well. This study aims to evaluate flesh quality and muscle cellularity of meagre of three different sizes: 800, 1500 and 2500 g. Results showed a higher fat content in larger fish (2.9% compared to 1.3% in small fish), and that texture was not affected by fish size. In terms of muscle cellularity, a higher frequency of smaller fibres was observed in 800 and 1500 g (33% compared to 18% in 2500 g) meagre, whereas in 2500 g meagre, there was a higher frequency of larger fibres. Muscle fibre density was reduced with fish weight (431 and 297 fibres mm^?2 for 800 and 2500 g meagre, respectively). In conclusion, this study shows that meagre of different weights are different in terms of fat content and muscle cellularity and that 800 g meagre seems to have a good potential for being commercialised.     

The effect of linseed and psyllium fibre on the gelling properties of unwashed mince from farmed meagre (Argyrosomus regius)

The gelling properties of farmed meagre (Argyrosomus regius) mince mixed with linseed and/or psyllium fibres (up to 4.0%, w/w) were studied. The effects of chilled storage time (15 days vs. 1 day) and cold gelling (setting at 2 ± 2 °C) were measured. Linseed addition increased ω3 PUFA content and worsened the gel products' texture. Psyllium functional fibre addition had only a negative effect upon breaking force and deformation, not affecting the remaining textural properties and improving water‐holding capacity (WHC) from 61–77 to 70–85%. The incorporation of 4.0% (w/w) psyllium seems to be advisable. Quality of heat‐induced meagre gels was unaffected by chilled storage time. Production of an acceptable cold set gel is feasible provided that enough time is allowed for completion of the setting process. Overall results showed a potential for combining small‐sized meagre (<2 kg) and psyllium fibres to produce high added‐value functional foods.     

Lipid distribution and composition of commercially farmed atlantic salmon (salmosalar)

Skin, red and white muscle, belly flap, dorsal fat depot, backbone, head, visceral tissue and liver of commercially farmed Atlantic salmon (Salmo salar) were analysed for total lipid content, lipid classes and fatty acid composition. The fat is deposited in a number of tissues and organs with the highest level in the dorsal fat depot (38.4% of wet weight), red muscle (27.2%) and belly flap (28.1%). The fat content in white muscle is 9.6% of wet weight. The lipid class distribution is nearly uniform throughout the fish body. The belly flap contains the highest amount of triacylglycerols (98.8% of total lipid) and white muscle and visceral tissue have the lowest levels, 93.3% and 93.1%, respectively. The variation in total saturates, monoenes, polyenes, n-6 and n-3 fatty acids was much less between tissues than the variation in total lipid content. In the edible part, the belly flap (16.7%) contained significantly lower levels of n-3 fatty acids than red (18.4%) and white muscle (19.7%) mainly due to lower level of 22: 6n-3 and 20: 5n-3 fatty acids.     

草鱼片热风干制过程中脂质氧化特性研究

探讨热风干燥过程中青鱼片油脂的变化情况。在青鱼片的不同干燥阶段提取油脂,检测油脂氧化程度,油脂成分及脂肪酸组成的含量变化。在干燥过程中鱼片油脂的过氧化值、羰基价和酸价显著性升高(P<0.05)。随着甘油三酯和磷脂含量的下降,游离脂肪酸含量明显增加,表明在干制过程中油脂在酯酶和磷酸化酶的催化下发生了水解反应。在总油脂和总磷脂中多不饱和脂肪酸,尤其是二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量下降。在游离脂肪酸中,除DHA以外的多不饱和脂肪酸含量均显著升高。研究结果表明,青鱼片热风干燥过程中其油脂被氧化,同时发生脂质降解,特别是不饱和脂肪酸被释放为游离态。     

Effect of grape dietary fibre on the storage stability of innovative functional seafood products made from farmed meagre (Argyrosomus regius)

Two groups of farmed meagre (Argyrosomus regius) sausages were studied regarding quality changes and antioxidant capacity during a 98‐day storage experiment at 2 ± 2 °C. Control sausages contained 3.9% (w/w) of inner pea dietary fibre (IPDF) and the other group contained 0.9% (w/w) IPDF plus 3.0% (w/w) of antioxidant grape dietary fibre (AGDF). The control and AGDF meagre sausages presented a high nutritional value, given their low caloric content, fatty acid profile, amino acid composition and high DF content. Both products were remarkably stable over storage time. The AGDF had an effective antioxidant capacity, proven not only by the radical scavenging activity (90.0–91.0% vs. 82.1–85.4%) and reducing power (8.13–9.10 mg ascorbic acid equivalent g^‐1 vs. 4.16–4.24 mg ascorbic acid equivalent g^?1) measurements, but also by the lower thiobarbituric acid reactive species (TBARS) values (0.78–1.10 vs. 1.50–2.08 mg malonaldehyde kg^?1) over storage time. AGDF seemed to present antimicrobial effect, since on the 63rd day (beginning of significant microbial growth), the control sausages had more than 3 log CFU g^?1 and AGDF sausages much <3 log CFU g^?1. The sensory assessment pointed to some loss of textural quality, more accentuated in the AGDF sausages.     

Changes in lipid class and fatty acid composition during maturation of mesocarp of oil palm (Elaeis guineensis) variety dura

The deposition of oil, major lipid classes, and the constituent fatty acids of the oil palm fruit mesocarp were investigated to gain a better insight into the accumulation of these components. The oils were extracted with chloroform-methanol 1:2 (v/v) and were fractionated by silicic acid column chromatography into classes. Fatty acids were analysed by gas-liquid chromatography. Shortly after anthesis, lipids, mainly phospho- and glyco-lipids, were a small proportion of the mesocarp. With time the lipid content increased, until at maturity it accounted for about 60% of fresh mesocarp weight. Approximately 97% of the lipid at maturity was neutral lipid, essentially triacylglycerol. Maximum oil quantity was obtained at 22 weeks after anthesis. The active lipid accumulation period was from weeks 18 to 22 after pollination. Contrary to previously published data, palmitic, oleic and linoleic acids were characteristically present at all stages of oil accumulation. Linolenic acid was present in the neutral lipids from immature mesocarp of the oil palm fruit, but was probably diluted out in mature palms. Appreciable amounts of linolenic acid were present in the polar lipid fractions.     

厦门白姑鱼腌制加工过程中的脂肪酸变化分析

探讨厦门白姑鱼（Argyrosomus amoyensis）腌制加工过程中的脂肪酸的变化,并结合脂肪氧化相关指标：过氧化值（peroxide value,POV）及硫代巴比妥酸反应物（thiobarbituric acid reactive substance,TBARS）值,确定脂肪氧化对脂肪酸组成的影响。从腌制加工的7 个关键工序中取样,采用气相色谱-质谱联用法分析脂肪酸,同时考察POV及TBARS值。结果表明：厦门白姑鱼原料含26.41%的饱和脂肪酸（saturated fatty acids,SFA）、20.26%的单不饱和脂肪酸（monounsaturated fatty acids,MUFA）和53.33%的多不饱和脂肪酸（polyunsaturated fatty acids,PUFA）,共24 种,必需脂肪酸占12.49%,二十碳五烯酸（eicosapentaenoic acid,EPA）和二十二碳六烯酸（docosahexaenoicacid,DHA）占40.70%。在腌制加工中,SFA含量显著增加,MUFA含量和PUFA含量显著降低（P＜0.05）。POV和TBARS值都呈现了先增后减的趋势,分别在烘干1 d和3 d出现峰值。相关性分析表明,SFA与MUFA呈显著负相关（P＜0.05）,与PUFA呈极显著负相关（P＜0.01）,MUFA和PUFA没有相关性;SFA与POV和TBARS值呈现显著正相关（P＜0.05）,而PUFA与POV和TBARS值分别呈显著（P＜0.05）和极显著负相关（P＜0.01）。因此,厦门白姑鱼脂肪酸种类多,含有丰富的不饱和脂肪酸,腌制加工过程对主要8 种脂肪酸有显著影响,脂肪的氧化使SFA含量增加,同时使PUFA含量降低,PUFA更容易发生氧化。     

Long Chain Omega-3 Fatty Acid Levels in Loin Muscle from Transgenic (fat-1 gene) Pigs and Effects on Lipid Oxidation During Storage

Studies suggest a diet rich in long chain omega-3 fatty acids (LCn3) can promote visual, neural and vascular health. Pork muscle typically has small amounts of LCn3. A transgenic technology involving the fat-1 gene has been developed to increase LCn3 in various pig tissues; however, pork loin muscle has not been examined to date. We have determined that the LCn3 content in loin muscle (Longissimus) from fat-1 pigs was 1.59–2.24 g/100 g lipid compared to 0.34–0.38 g/100 g lipid in control samples. Lipid oxidation products were measured in ground and salted loin muscle from control and fat-1 pigs during storage at ?4°C. There was no clear trend as to whether the fat-1 gene technology increased or decreased oxidative stability of the muscle during storage based on lipid peroxide and thiobarbituric acid reactive substances (TBARS) values. There were a greater number of volatiles detected in stored loin from fat-1 pigs compared to control. Volatiles common to control and fat-1 pigs were elevated in stored loin from fat-1 pigs. This is the first report indicating that the use of fat-1 transgenic technology significantly increases the amount of desirable LCn3 in pork loin muscle.     

脂筏在反式脂肪酸诱导心血管疾病过程中的研究

探讨脂筏在反式脂肪酸诱导心血管疾病过程中的作用机制,为研究脂筏和心血管疾病的关系提供科学依据。     

蓖麻籽脂质提取和甲酯化衍生优化及其脂肪酸组成分析

采用不同方法对蓖麻籽的脂质提取和甲酯化衍生效果进行研究,并对其脂肪酸组成进行分析.结果表明:不同方法对蓖麻籽的脂质提取和衍生化效果存在显著差异(P＜0.05);二氯甲烷-甲醇法的脂质提取率为58.25％,且具有低毒、溶解性强和提取完全的优点,是蓖麻籽脂质提取的有效方法;酸碱结合法具有衍生完全且副反应少等优点,能更好地反映蓖麻籽脂肪酸的真实组成,是蓖麻籽脂质甲酯化衍生的理想方法.同时蓖麻籽脂肪酸以蓖麻油酸(76.43％～86.50％)、亚油酸(4.88％～6.27％)和油酸(2.70％～4.18％)为主,并含有少量的棕榈酸、硬脂酸以及亚麻酸和二十碳烯酸.     

Lipid Oxidation Potential of Beef, Chicken, and Pork

Beef and pork longissimus dorsi and semimembranosus muscles and chicken breast and thigh muscles were excised 24 hr postmortem from carcasses of marketweight grain-finished feedlot beef cattle, marke-tweight hogs on a typical finishing diet, and broilers on a commercial grain diet. Muscle samples were immediately ground and formed into patties and stored raw or after cooking, at 4°C (cooked) or ?20°C (raw and cooked). TBA values (on sample weight basis) of frozen raw samples were higher for beef and pork than for chicken, as was heme iron content. However, TBA values of cooked samples were highest for chicken thigh muscles, which contained the most polyunsaturated fatty acids, at all storage temperatures.     

The chemical composition of different edible locations (central and edge muscles) of flat fish (Lepidorhombus whiffiagonis)

The chemical composition of the different edible locations (central and edge muscles) of a flat fish (megrim, Lepidorhombus whiffiagonis) was comparatively analysed at both body sides. Higher moisture and lower lipid contents were obtained in central muscles than in edge ones. Edge sites showed higher triacylglycerols and sterols contents and lower mean phospholipids values than central muscles. A higher α‐tocopherol presence was observed in the lipid fraction of central muscles than in the edge ones. For both fish sides, fatty acid (FA) analysis showed lower monounsaturated FA and higher polyunsaturated FA contents and ω3/ω6 ratios in central muscles. Presence of essential elements (Co, Cu, Mn, Se, Zn) did not provide differences among sites considered. Concerning toxic elements, As content showed greater levels in central muscles than in their corresponding edge sites for both fish sides, upper zones showed higher mean scores in As, Cd, Cr, Hg, Ni, Pb and V.     

Chemical Characterization of Liver Lipid and Protein from Cold-Water Fish Species

ABSTRACT:  The largest US harvests of marine fish for human consumption are from Alaska waters. Livers from these fish are combined with other fish offal and made into fish meal and oil or discarded. The purpose of this study was to characterize liver lipids and proteins from important commercial species including walleye pollock (WP), pink salmon (PS), Pacific halibut (PH), flat head sole (FS), and spiny head rock fish (RF), and underutilized species including arrow tooth flounder (AF) and big mouth sculpin (BS). Liver lipid content ranged from 50.3% in WP to 3.3% in PS. Protein content ranged from 7.7% in WP to 18.4% in BS. PS livers had the highest content of ω-3 fatty acids at 336 mg/g of oil and AF had the lowest content at 110 mg/g of oil. There were significant differences in the content of 9 amino acids with methionine and lysine values ranging from 2.66% to 3.43% and 7.19% to 9.45% of the total amino acids, respectively. Protein from the cold water marine fish livers was of high quality and the oils contained substantial quantities of ω-3 fatty acids. Fish livers had distinct chemical properties and can be used for the development of unique food ingredients.     

Lipid levels in cabbage leaves (Brassica oleracea)

Cabbage (Brassica oleracea L, var Glory) is one of the cruciferous vegetables. The objective of this study was to investigate the neutral, glyco- and phospholipids of cabbage and their fatty acid composition. Lipids from its leaves were extracted and fractionated into neutral lipids, glycolipids and phospholipids. The fatty acids of each fraction were analysed by gas liquid chromatography.     

Utilization of extruded linseed to modify fatty composition of intensively-reared lamb meat: Effect of associated cereals (wheat vs. corn) and linoleic acid content of the diet

Sixty male lambs were used in two trials to study the efficiency of transfer and elongation of linolenic acid (ALA) in muscle and caudal adipose tissue and to assess factors affecting this process and related changes in fatty acid (FA) profile. In experiment 1, lambs were fed a control diet or extruded linseed (L) diet either with wheat (W, rapid starch) or corn (C, slow starch). In experiment 2, lambs were fed L with “normal” rapeseed, or high-oleic rapeseed, or soybean. In experiment 1, L increased ALA proportion and total n-3 PUFA in muscle and adipose tissue. In adipose tissue but not in muscle, LC lambs had higher proportion of ALA than LW lambs. In experiment 2, increasing linoleic acid (LA) intake increased LA proportion in muscle and adipose tissue but did not modify ALA proportion. Moreover, in muscle, it did not change the desaturation and elongation processes of ALA to long-chain n-3 PUFA.