The use of chromic oxide as a food marker —a warning

Four mixtures of ground barley and soya bean meal were prepared; the first had no further additive, the second had 10% soya bean oil, the third 0.05% chromic oxide and the fourth both 10% soya bean oil and 0.05% chromic oxide. Each of these mixtures was then dried in three ways: at 30°C in vacuo and at 60 and 100°C in a forceddraught oven. The total fatty acid content and the fatty acid composition of each sample was determined either by direct esterification of the fatty acids with methanolsulphuric acid or by extraction into chloroform-methanol followed by esterification with sodium methoxide. When the mixture containing both oil and chromic oxide was heated at 100°C, about 25% of the polyunsaturated fatty acids were lost when they were directly esterified and about 50% when the fat was first extracted from the mixture. It is concluded that this loss is probably due to oxidation of the polyunsaturated fatty acids by the chromic oxide and that the additional loss observed when the extraction method was used is due to partial insolubilisation of the triglyceride by these oxidised fatty acids.     

Physicochemical Properties of Microencapsulated ω‐3 Salmon Oil with Egg White Powder

The objective of this study was to produce microencapsulated omega(ω)‐3 fatty acids (PUFAs) fortified egg white (EW) powders and to characterize their nutritional and physical properties. Stable emulsions (E‐SO‐EW) containing 3.43 (g/100 g) salmon oil (SO), 56.21 (g/100 g) EW, and 40.36 (g/100 g) water and a control (E‐EW) containing EW and water were prepared. E‐SO‐EW and E‐EW were separately spray dried at 130, 140, and 150 °C inlet air temperatures. This resulted in 3 microencapsulated SO fortified EW powders (SO‐EW), and 3 dried EW powders (DEW). The powders were analyzed for microencapsulation efficiency (ME), color, fatty acids methyl esters, protein, fat, moisture, ash, amino acids, minerals, microstructure, and particle size. The EPA and DHA content of SO and the ME of the powders were not affected by the inlet air temperature. The crude protein content of SO‐EW powders was approximately 24 (g/100 g) lower than dried EW powders. Leucine was the most abundant essential amino acid found in all the powders. Most of the powders’ median particle size ranged from 15 to 30 μm. The study demonstrated that microencapsulated ω‐3 salmon oil with high quality EW protein can be produced by spray drying.     

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.     

Effects of ultrasound on the physicochemical properties and microstructure of salted‐dried grass carp (Ctenopharyngodon idella)

Ultrasound treatment was used for accelerating drying process and shortening drying time of salted‐dried grass carp, in parallel with evaluation of physicochemical properties and microstructure. The grass carp blocks were salted with ultrasound‐assisted treatment at 0–480 W, 40 kHz for 120 min, then put into heat pump dryer for drying at 50% humidity, 30 °C for 50 hr. The moisture content results showed that ultrasound treatment could significantly promote water loss rate. As the ultrasound power increased, the hardness, the relative content of monounsaturated fatty acid and polyunsaturated fatty acid and total content of free amino acid decreased while the saturated fatty acid and sensory scores increased, respectively. Furthermore, microstructure of the dried‐salted grass carp was studied using paraffin sections and the scanning electron microscope to understand the change of microstructure. In general, ultrasound‐assisted salting significantly increased drying rate, and improved the quality of salted‐dried grass carp. This study shows the potential application of ultrasound in food drying process.

Practical applications

The ultrasound was applied in order to facilitate the traditional process to produce salted‐dried grass carp. And physicochemical properties and microstructure of salted‐dried fish were measured. The results showed that the application of ultrasound could significantly promote the mass transfer of water and improved the product's appeal for customers. The outcome of this study demonstrated a method for producing better quality dried‐salted fish products with a fast speed in the future and showed a great potential of ultrasound in food drying process.     

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.     

萝卜籽油的提取工艺及其组分分析

水预处理后用二氯甲烷作溶剂提取萝卜籽中的油脂,在单因素试验基础上,以液固比、提取温度、提取时间为因变量,萝卜籽油提取率为响应值,采用响应面分析法优化提取工艺。获得的最佳提取工艺条件为液固比21.8:1(mL/g)、提取时间1.76h、提取温度27.3℃,在此条件下萝卜籽油的提取率为35.58%,提取效率达9 5.3 8%;萝卜籽油中含有多种脂肪酸,其中芥酸、油酸、亚油酸、二十碳一烯酸、α-亚麻酸含量较高,不饱和脂肪酸占总脂肪酸的量超过88%,莱菔素含量达89.5mg/kg。     

Distribution of fatty acids in edible organs and seed fractions of borage (Borago officinalis L.)

BACKGROUND: Borage (Borago officinalis L.) is currently used as a vegetable in the north of Spain. The edible parts of the plant are the petioles, leaves and stems. The objective of this study was to determine the oil and fatty acids content in the edible tissues (leaves, petioles and stems) and seed fractions (endosperm + cotyledon, seed coat and elaiosome) of white‐ and blue‐flowered borage accessions. RESULTS: Leaves showed higher mean values of oil content (2.7%) than petioles and stems (1.1% and 1.4%, respectively) in both, blue‐ and white‐flowered material. The most abundant fatty acids in leaves were palmitic, linoleic, α‐linolenic and stearidonic acids (about 75% of the total fatty acids), while in petioles and stems myristic and linoleic acids were most abundant (about 60% of the total fatty acids). Palmitic, oleic, linoleic and γ‐linolenic (GLA) acids were the major fatty acids of seed coat and endosperm + cotyledon in borage seeds (85% of the total fatty acids), while palmitic, stearic, oleic and linoleic acids were the most abundant fatty acids of elaisome in borage seeds (80% of the total fatty acids). CONCLUSION: This paper shows that green parts of borage contain substantial amounts of omega‐3 and omega‐6 fatty acids, which are essential fatty acids for animal and human nutrition. Thus, borage could be a ‘power food’ of the future because of its content of unsaturated fatty acids, particularly the essential fatty acids, which have great potential to prevent cardiovascular disease, cancer and infectious diseases. Copyright © 2007 Society of Chemical Industry     

Changes of bioactive components in berry seed oils during supercritical CO2 extraction

The objective of the work was to elucidate the chemical composition of fractions of oil extracts obtained during the supercritical extraction on a semi‐industrial scale from strawberry (Fragaria x ananassa Duch.), chokeberry [Aronia melanocarpa (Michx.)], and raspberry (Rubus idaeus L.) seeds from industrial press cake. The oil extracts differed in terms of their content of bioactive components: carotenoids, tocopherols, chlorophylls, and fatty acids. Raspberry seed oil was the richest source of tocopherols (620.1–2166.7 mg kg^?1) and α‐linolenic acid (above 37%). Chokeberry seed oil had the highest content of linoleic acid (above 70%), and α‐tocopherol (166.0–1104.8 mg kg^?1). Strawberry oil was characterized by the highest content of chlorophylls and α‐linolenic acid (above 30%). It was showed that the oil fraction collected at the beginning of extraction is characterized by a high acid value, which requires purification steps to be used for food purposes.

Practical applications

Strawberry, raspberry, and chokeberry by‐products left over from the production of concentrated juice are a valuable source of oils rich in n‐3 and n‐6 polyunsaturated fatty acids, tocopherols, and carotenoids. The research showed that the fractionation of extracts in the course of supercritical extraction leads to oils with varying amounts of different bioactive compounds, and thus to products with potentially wide applications. Seeds oils have high potential utility as a source of unconventional oil for cosmetic and pharmaceutical sectors and biodiesel. Their targeted utilization may be exploited for economic, environmental and health benefits.     

四棱豆油脂、脂肪酸、蛋白质、氨基酸的分析

以4 个四棱豆品种的种子为材料,采用索式提取法、毛细管柱测定总脂肪含量及分析各脂肪酸含量;利用凯氏定氮法、全自动氨基酸分析仪测定蛋白质总量及各蛋白氨基酸组成。结果表明,四棱豆种子中油脂总量在20%～22%,主要含有28 种脂肪酸,油酸占单不饱和脂肪酸的90.7%;多不饱和脂肪酸主要为亚油酸、α - 亚麻酸和EPA;饱和脂肪酸平均含量为25.76%,主要为棕榈酸和硬脂酸。蛋白质总量在38% 左右,必需氨基酸含量丰富。     

Effects of drying process on biochemical and microbiological quality of silverside (fish) Atherina lagunae

Changes in biochemical and microbiological quality of silverside during two drying process were investigated. Total fatty acid and amino acid contents in silverside were 5.42 and 10.9 g 100 g^?1 fresh sample, respectively, in which, palmitic acid and glutamic acid were the most abundant. N‐3 and n‐6 polyunsaturated fatty acids (PUFA) levels were 0.59 and 0.62 g 100 g^?1 fresh silverside respectively. After hot air and solar drying treatments, Peroxide value and thiobarbituric acid reactive substances of the total lipids increased significantly (P < 0.05) to reach 2.58 and 3.41 meq active O₂ kg^?1 oil and 0.87 and 1.27 mg MA kg^?1 oil, respectively. Fatty acid profile of non‐polar lipid remains unchanged during experimental drying process. However, PUFA (% of total fatty acids) of polar lipid decreased significantly (P < 0.05) during both drying process with lower levels in solar drying process. Drying conditions had a significant effect on the microbiological quality. Therefore, mesophiles and total coliforms increased within drying treatment with higher counts in solar drying process.     

Stabilizing Smoked Salmon (Oncorhynchus gorbuscha) Tissue after Extraction of Oil

ABSTRACT: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Discarded pink salmon (Oncorhynchus gorbuscha) tissues were preserved using a combination of smoke-processing and acidification with lactic acid bacteria (LAB). All samples were analyzed for moisture, protein, ash, and lipid contents. Bacterial cell counts, pH, and lactic acid concentrations were recorded as a measure of LAB viability. Neither raw nor smoked salmon were free from spoilage during 60 d of storage. Only fermented samples successfully stabilized below pH 4.7, while retaining lactic acid concentrations over 15 g/L during storage. When smoked, fermented salmon head tissues were dried, the pH of the resulting high-protein “cracker” was significantly lower than when crackers were prepared only from the smoked (but not fermented) salmon material. Both cracker varieties retained valuable polyunsaturated fatty acids. This research suggests that salmon-head tissues discarded after oil extraction represent a good source of protein and high-value fatty acids in a shelf-stable form. Practical Application: Alaska salmon oils are rich in n-3 polyunsaturated fatty acids and are highly valued by the food and pharmaceutical industries. However, the tissue that remains after oil extraction does not have an established market. Material produced from salmon tissue discarded after oil extraction may represent a valuable resource for preparing high-protein crackers and other fish-based food products. In addition to providing a unique smoke-flavoring, the smoked, fermented fish material may also impart antioxidant factors thereby extending the shelf life of the product.     

光核桃仁油和蛋白质同步提取工艺优化及油脂品质分析

以西藏光核桃为原料,采用水剂法提取结合酶法破乳技术分离其中的油脂和蛋白质,优化了光核桃仁油脂与蛋白质水剂法同步提取的工艺条件,并分析了油脂的主要理化指标及脂肪酸组成。结果表明:西藏光核桃仁油与蛋白质同步提取最优工艺为物料粒径150目、液料比8:1 (mL/g)、pH 10、浸提温度50℃、提取时间5h、搅拌速度80r/min,该工艺条件下核桃仁油提取率为(67.79±2.97)%,蛋白质提取率为(78.13±1.53)%。光核桃仁油脂具有优良的理化性质,并检测出12种脂肪酸组分,主要由顺式油酸(57.32%)、亚油酸(31.65%)、棕榈酸(6.49%)和硬脂酸(2.29%)组成,其中饱和脂肪酸7种,单不饱和脂肪酸3种,多不饱和脂肪酸2种;油脂以不饱和脂肪酸为主,相对百分含量为89.43%,其中多不饱和脂肪酸相对百分含量为31.76%,单不饱和脂肪酸相对百分含量为57.67%。     

提取工艺对辣椒籽油品质及香气成分的影响

为选择较优辣椒籽油制备工艺,以氧化值、酸价、色泽、脂肪酸组成、挥发性物质等为指标,比较酶解-乙醇辅助法和乙醇常温浸提法2种制备工艺对辣椒籽油的品质及香气成分的影响。结果表明:酶解-乙醇辅助法和常温浸提法2种制备工艺所得辣椒籽油均呈橙黄色,酸价值≤4.0 mg/g,过氧化值≤12meq/kg;辣椒籽油中辣椒素含量分别为1.46,0.54mg/g。制备工艺对脂肪酸组成影响不显著(P0.05),对含量影响显著(P0.05);辣椒籽油饱和脂肪酸含量分别为14.89%和16.3%,多不饱和脂肪酸分别为69.8%和70.87%。可见辣椒籽油中多不饱和脂肪酸含量丰富,酶解-乙醇辅助法工艺能够显著降低饱和脂肪酸含量。酶解-乙醇辅助法中鉴定出挥发性物质56种,多于常温浸提法的52种和市售辣椒油的42种。可见,酶解-乙醇辅助法相对常温浸提法而言,有助于辣椒油品质的提升。     

白果油的提取及脂肪酸组成分析

以白果为原料,用索氏提取和超临界萃取(SFE)两种方法从中提油,比较了不同提取方法对油得率的影响,测定了索氏提取油的理化特性,用气相色谱法和高效液相色谱法分别测定两种方法提取油的脂肪酸组成和VE的含量。结果表明,与常规植物油脂理化指标相比,白果油比重偏高,碘值较大,说明白果油不饱和程度较高;气相色谱分析结果表明两种方法提取的白果油中均含有多种不饱和脂肪酸,且不饱和脂肪酸含量均大于91%,而其中亚油酸和油酸的总含量均大于75%,索氏提取和超临界萃取的油中VE的含量分别为670 mg/kg和610 mg/kg。     

不同甲酯化方法对裂壶藻产油脂肪酸的影响及GCMS分析

为了研究不同的甲酯化方法对裂壶藻产油脂肪酸的影响,本文通过对裂壶藻进行发酵培养得到纯藻体,再经过酶法破壁、冷冻干燥得到干藻体后采用索氏提取法提取油脂。运用酸法、碱法和三氟化硼法三种甲酯化方法对藻油进行处理,基于气相色谱-质谱联用(GC-MS)技术分析了藻油中DHA(二十二碳六烯酸)等脂肪酸的组成和含量。结果表明:酸法、碱法、三氟化硼法分别鉴定出11种、19种和12种脂肪酸,占裂壶藻藻油总量的89.50%、97.88%和90.12%。其中酸法酯化的藻油中DHA占脂肪酸总量的38.89%;碱法酯化的藻油中DHA占脂肪酸总量的46.76%;三氟化硼法酯化的藻油中DHA占脂肪酸总量的40.54%。所以,碱法相较于酸法和三氟化硼法有明显的优势,更适合用于裂壶藻藻油的脂肪酸分析。进一步对碱法的甲酯化温度进行梯度实验,结果表明温度为55℃时,DHA的相对含量为47.45%,藻油的甲酯化效果最好。这一研究对长链多不饱和脂肪酸的检测鉴定有着重要的意义。     

伞花木种仁油的理化性质及脂肪酸组成分析

采用索氏抽提法提取伞花木种仁油,并对其理化性质及脂肪酸组成进行分析。结果表明:伞花木种仁粗脂肪含量为36.42%,伞花木种仁油酸值(KOH)为0.70 mg/g,皂化值(KOH)为184mg/g,碘值(I)为111 g/100 g;伞花木种仁油含有14种脂肪酸,主要为油酸(35.87%)、亚油酸(18.39%)和亚麻酸(17.18%),不饱和脂肪酸含量高达92.37%。伞花木是一种具有很高开发价值的油脂植物资源。     

水酶法提取斑点叉尾鮰内脏油的工艺研究

为提高鱼类加工废弃物的综合利用率,以斑点叉尾鮰内脏为原料,采用水酶法制备鱼油。结果表明：水酶法提取鱼油的最佳工艺条件为初始pH7.5、料液比1:1、加酶量3500U/g、酶解温度55℃、酶解时间0.5h,该条件下鱼油的提取率达到80.94%;提取到的鱼油(即粗鱼油)外观呈黄褐色,具有鱼腥味和轻微的酸败味,其过氧化值较低,而酸值相对较高;粗鱼油中的饱和脂肪酸相对含量为19.42%,单不饱和脂肪酸和多不饱和脂肪酸分别为61.76% 和16.83%,Σn-3/Σn-6 的脂肪酸比值达到3.63。表明斑点叉尾鮰内脏是生产鱼油的良好来源。     

Determination of the lipid content in fish muscle by a self‐calibrated NMR relaxometry method: comparison with classical chemical extraction methods

A low‐cost, accurate NMR method was developed to determine the lipid content in fish flesh. The fish samples are dried before NMR measurements, and the method is self‐calibrated with an oil reference. The NMR technique gave an intermediate fat content value, 4.7% lower in relative value than those obtained by a chemical cold extraction method and 6.7% higher than those from a petroleum ether extraction method at high temperature. Taking into account this systematic bias, the prediction error was only 3 g kg^?1 fat content between NMR and Soxhlet method determinations (R² = 0.98). The NMR technique thus offers a promising alternative method for determining the lipid content in previously dried fish flesh, since it is rapid, easily usable and solvent‐free, unlike chemical extraction methods. Furthermore, this accurate NMR method should be valuable to calibrate the fast but less accurate NMR, NIR and microwave methods based on fresh samples and to estimate the fat content in other animal meats when the fat is maintained in an amorphous state. © 2001 Society of Chemical Industry     

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.     

8种抗寒平欧杂交榛子油脂成分分析及比较

比较8种平欧榛子的差异性,利用索氏提取法测定油脂含量,气相色谱法和比色法进行油脂脂肪酸组成和α-VE含量分析,聚类分析用于区分其类别。结果表明:8种平欧榛子有显著差异,含油量平均为56.36%,范围为52.92%~59.24%;单不饱和脂肪酸、多不饱和脂肪酸、饱和脂肪酸的平均相对含量分别为72.54%、16.11%、7.85%;最丰富的脂肪酸是油酸,平均相对含量为72.29%,亚油酸与油酸总含量超过85%;α-VE含量为113.42~285.16μg/g。用3个主成分PC1(43.384%)、PC2(34.436%)、PC3(12.606%)作为合成变量通过聚类分析可得到4个类群:4#、5#、6#、7#为一类,8#为一类,2#、3#为一类,1#为一类。