Fat Fatty Acid Composition Research Articles

The impact of glycerol monostearate's similarity to fats and fatty acid composition of fats on fat crystallization, destabilization, and texture properties of ice cream.

Fat significantly affects the properties of ice cream. Prior studies have investigated the correlation between fat crystallization, fat destabilization, and ice cream quality. However, the role of fatty acid composition, the similarity between fat and emulsifier in these characteristics, and their impact on final product quality remains unclear. To investigate the influence of the fatty acid composition of fats, as well as their similarity to glycerol monostearate (GMS), on fat crystallization and destabilization during the aging and freezing stages, ice creams were formulated using a combination of two types of fats (coconut oil and palm olein) in five different ratios. In oil phases, decreased saturation of fatty acids (from 93.38% to 46.69%) and increased similarity to GMS (from 11.96% to 46.01%) caused a reduction in the maximum solid fat content. Moreover, the rise in unsaturated long-chain fatty acids (from 34.61% to 99.57%) and similarity to GMS enhanced the formation of rare and coarse fat crystals, leading to a sparse crystalline network. This, in turn, reduced the crystallization rate and the stiffness of the fat in emulsions. Assuming consistent overrun across all ice creams, the enhanced interactions between fat globules in ice cream improved its hardness, melting properties, and shrinkage. The crystalline properties of fat in emulsions were influenced by oil phases, impacting fat destabilization and ultimately enhancing the quality of ice cream. The present study offers valuable insights for the optimization of fat and monoglyceride fatty acid ester selection, with the potential to improve ice cream quality. © 2023 Society of Chemical Industry.

The Effect of Essential Oils on the Survival of Bifidobacterium in In Vitro Conditions and in Fermented Cream

Essential oils derived from plant materials are a mixture of compounds that exhibit antibacterial properties. Due to their distinct aroma, they also serve as a desirable natural additive for various food products, including dairy products. In this study, the essential oils of lemon peels, clove buds, and juniper berries were obtained by steam distillation and characterized using gas chromatography–mass spectrometry to determine their chemical compositions and effects on the viability of seven Bifidobacterium strains. Furthermore, the effect of essential oils on the viability of Bifidobacterium animalis subsp. lactis Bb-12 was investigated in cream samples during fermentation and after storage for 21 days at 6 °C. The fatty acid composition of fat extracted from essential oils containing sour cream samples and the volatile aroma compound profile of the sour cream samples were also determined chromatographically. Among the 120 compounds identified, monoterpene hydrocarbons were dominant in the essential oils of lemon peels (limonene and γ-terpinene) and juniper berries (sabinene and β-myrcene), while eugenol and eugenol acetate were abundant in the essential oil of clove buds. In addition to these compounds, butanoic and acetic acids were found in the tested sour cream samples. In turn, fat extracted from these samples was rich in saturated fatty acids, mainly palmitic acid. Among the tested strains of the genus Bifidobacterium, B. animalis subsp. lactis Bb-12 was the most sensitive to the essential oils of clove and juniper, as indicated by the larger growth inhibition zones. However, both the concentration and type of essential oils used had no effect on the number of cells of this strain present in the cream samples immediately after fermentation and after its 21-day storage, which suggests that the tested essential oils could be a natural additive to dairy products.

Fatty acid composition of swine fat when using different feedstuffs in diets

Human health is largely determined by the influence of environmental factors, including the quality of foodstuff. Nutrition is one of the most important factors, so the application of modern knowledge about the energy value and fatty acid composition of basic foods, as well as the organization of a rational diet of people on this basis can significantly improve it. This article analyses data on the fatty acid composition of fat when using different feedstuffs in swine diets. The use of additives in animal diets in order to increase their productivity affects the quality of products, in particular the fatty acid composition of swine fat, which influences the physical and chemical properties and technological properties of food products. The role of saturated and polyunsaturated fatty acids in human and animal bodies, which play an extremely important role in metabolism, is described. The data on their content in fat and swine products as the main source of these substances in the human diet are summarised. The importance of a balanced intake of polyunsaturated fatty acids in the human diet is discussed, which contributes to the prevention of various diseases, and a review of the results of studies on the effect of various feedstuffs on the fatty acid composition of swine products is given, since the content of individual fatty acids that are not synthesised in the animal body is affected by feed quality and the presence of fatty acids in lipids of feed, which determine the quality of human foods.

Моніторингові дослідження якості кондитерських жирів та глазурей за жирнокислотним складом

Availability of a wide range of fats and growing production volumes brings to the forefront the issue of reasonable choice of their use in the manufacture of confectionery products and requires quality control of the most common domestic market confectionery fats and glazes. Purpose of the work is to evaluate the quality of the fatty acid composition of fats and glazes manufactured in Ukraine these being in active demand in the food industry for various fillings of confectionery products, candies and chocolate. Subject of study: fatty acid composition and content of trans-isomers of confectionery fats and glazes which are used for the production of confectionery products and affect their nutritional value. Research methods: chromatographic method using gas chromatographs «Cupol-55» and «CrystalLux 4000». Results of the study: it was found that all samples of confectionery fats and glazes differ in fatty acid composition, which is associated with the composition of raw materials and methods of production. In particular, the vast majority of confectionary fats of the non-lauric type contained significantly less saturated acids, about 36-48 %, whereas the lauric type contained 70 %. A distinguishing characteristic was also the amount of monounsaturated acids, which were 25-31 % and 36-46 % for lauric and non-lauric confectionary fats, respectively. The total content of trans-isomers in the analyzed samples of confectionary fat was 0.12-2.88 %. However, elevated trans-C18 : 1 isomer content was shown for 2 of the 11 confectionery glaze samples: in confectionery glaze №155-D – 6,26 %, and in confectionery glaze № 264 – 21,11 %. The confectionary glaze samples are characterized by a more diverse composition of fatty acids at the expense of milk fat, as evidenced by the presence of short-chain acids C4-C10 and other animal fats (presence of conjugated linoleic acid). At the same time, the saturated acid content varied in a wide range from 25 to 47%. The obtained data can be used to produce food products with the predetermined consumer properties.

Determination of tail fat fatty acids profile in some local sheep breeds of Black Sea Region

In the study, the contents of tail fat fatty acid composition of 6-month-old male lambs in the breeds of Artlı, Çepni, Karayaka and Of grown in the Black Sea Region were examined. The content of saturated fatty acids in tail fat for the breeds of Artlı, Çepni, Karayaka and Of were respectively; 52.08%, 51.66%, 42.67%, 52.92% while the monounsaturated fatty acid contents were 33.25%, 33.12%, 33.07%, 32.34% respectively. The content of polyunsaturated fatty acids was determined as 0.76%, 1.20%, 0.64% and 0.87%, respectively. The presence of fatty acids desired for health was determined as 46.94% in Artlı, 51.03% in Çepni, 51.51% in Karayaka and 49.51% in the breeds of Of. In terms of polyunsaturated fatty acids in the composition of fatty acids, the highest rate was found in the Çepni breeds and the lowest in the Karayaka breeds. It has been determined that the fatty acid content has significant differences between breeds.

Effect of production system on fatty acid composition in subcutaneous adipose tissue of Ile de France lambs

Effect of production system on fatty acid composition in subcutaneous adipose tissue of Ile de France lambs

Tutorial for the Characterization of Fatty Acid Methyl Esters by Gas Chromatography with Highly Polar Capillary Columns.

The fatty acid composition of fats and oils is commonly determined by gas chromatography after preparing fatty acid methyl esters (FAME). Capillary columns coated with polyethylene glycol emerged as the preferred separation tool for the quantification of the polyunsaturated fatty acids contained primarily in marine oils. However, their selectivity is inadequate for measuring the trans fatty acids (TFA) contained in refined vegetable oils, dairy fats, and marine oils. Highly polar 100% poly(biscyanopropyl siloxane) capillary columns provide the necessary selectivity, but small differences in the phase polarity caused by column age, conditioning, or manufacturing variations affect the reproducibility of their separations of these complex samples. In this study, a simple procedure is described to compensate for small variations in column selectivity by adjusting the elution temperature. The balance between the dipole-induced dipole interactions and dispersive interactions was determined by measuring selectivity factors [SF(i)] corresponding to the elution of an unsaturated FAME such as 18:3n-3 relative to two saturated FAME such as 20:0 and 22:0. Knowing the SF(i) provided by the installed capillary column at a given elution temperature, and the SF(i) of the target separation, we propose a simple calculation to determine the necessary elution temperature adjustment to achieve (or restore) the desired separation. After determining the SF(i) which provides the optimal separation of TFA, the novel methodology was applied to the separation of refined vegetable oils, butter fats, and marine oils.

Fatty Acid Composition of Meat and Edible Offal from Free-Living Red Deer (Cervus elaphus).

The objective of the study was to characterize tissue-associated differences in the fatty acid composition of fat in skeletal muscles M. longissimus dorsi (loin), M. biceps femoris (hind quarter), and M. triceps brachii (shoulder), and internal organs (i.e., liver, heart, and kidney) from free-living red deer (Cervus elaphus) females (n = 11) hunted in Lithuania. Skeletal muscles were characterized by lower content of free fat compared with the offal. The highest percentage of saturated fatty acids was found in the liver fat, whereas the lowest percentage was in the heart. Red deer offal showed significantly lower and higher proportions of monounsaturated and polyunsaturated fatty acids compared to meat, respectively. Higher proportions of oleic fatty acid in the shoulder and hind quarter compared to the loin were the only significant differences between skeletal muscles. The lowest and the highest n-6 polyunsaturated/n-3 polyunsaturated fatty acids (n-6/n-3PUFA) ratio were found in the liver and heart, respectively. More favorable lower atherogenic index and higher hypocholesterolemic/hypercholesterolemic ratio found in the offal showed their high nutritional value, however, higher peroxidizability index indicated higher susceptibility to lipid peroxidation compared to skeletal muscles.

Involvement of polyunsaturated fatty acids in the control of energy storage and expenditure

Within heterotrophic organisms, fat, sugar and protein are required to bring energy. In humans, energy homeostasis (i.e.the balance between energy intake and energy expenditure) is tightly regulated. Obesity, characterized by an excess of white fat mass, is a consequence of dysregulation of this balance in which decreased energy expenditure plays an important role. Among dietary components, fat represents approximately 30% of daily intake. Recent studies have shown that, besides its caloric input, fatty acid composition of fat represents an important qualitative issue. The impact of ω6 and ω3 polyunsaturated fatty acids on weight gain and development has been extensively studied. Interestingly, the role played by these polyunsaturated fatty acids in energy expenditure has been also characterized and will be discussed in relation to the various organs involved, in particular brown adipose tissue.

COMPARATIVE QUALITY ASSESSMENT OF PEANUT AND PEANUT-FLAXSEED OIL

The aim of research is quality assessment of peanut and peanut-flaxseed oil for organoleptic and physico-chemical indicators, as well as the study of fatty acid composition of fat. It will determine the consumer properties of these products. Comparative studies of consumer properties of peanut and peanut-flaxseed oil for organoleptic indicators, fatty acid composition, acid and peroxide numbers are carried out. To determine the fatty acid composition of fat, the gas chromatography method is used. The measurement of the acidic and peroxide number of fat is performed by a titrimetric method. The research results of organoleptic and physicochemical parameters, as well as the fatty acid composition of peanut oil and peanut-flaxseed blend have shown that the flavor qualities of the developed oil are balanced and high, therefore new oil can be consumed by consumers. The enrichment of peanut oil with flaxseed helps improve the fatty acid composition beyond the set of a significant increase in unsaturated fatty acids (linoleic by 23 %, oleic by 28 %, linolenic by 96 %). It has also been proved that the use of flaxseed oil does not have a significant effect on the acceleration of the hydrolytic processes of vegetable oil fats. The expediency of mixing peanut and flaxseed oil is shown, which makes it possible to obtain new blended peanut-flaxseed oil, balanced by fatty acid composition.

Effects of Calcium Soaps of Animal Fats on Performance, Abdominal Fat Fatty Acid Composition, Bone Biomechanical Properties, and Tibia Mineral Concentration of Broilers

Effects of Calcium Soaps of Animal Fats on Performance, Abdominal Fat Fatty Acid Composition, Bone Biomechanical Properties, and Tibia Mineral Concentration of Broilers

Genetic parameters of measures and population-wide infrared predictions of 92 traits describing the fine composition and technological properties of milk in Italian Simmental cattle

The objectives of this study were to estimate, for the Italian Simmental cattle population, genetic parameters for 92 traits and their infrared predictions (IP) and to investigate the genetic relationship between measured traits (MT) and IP. Data for milk fat fatty acid composition (n = 1,040), detailed protein composition (n = 3,337), lactoferrin (n = 558), pH (n = 3,438), coagulation properties (n = 3,266), curd yield and composition obtained by a micro-cheese making procedure (n = 1,177), and content of Ca, P, Mg, and K (n = 689) were obtained using reference laboratory analysis. Infrared prediction for all the investigated traits was performed using 143,198 spectra records belonging to 17,619 Italian Simmental cows. (Co)variance components for MT and their IP were estimated in a set of bivariate animal model REML analyses and genetic correlations between MT and IP were estimated using all IP obtained at the population level. A significant positive relationship was observed between the coefficient of determination of the infrared prediction models and the phenotypic and genetic variation of the IP. The decrease in the estimated genetic variance of IP compared with MT was on average 64%. For traits exhibiting calibration models with coefficients of determination in cross-validation (R2CV) greater than 0.9, the decrease in the genetic variance ranged from approximately 20 to 50%. Most traits (88 out of 92) exhibited lower heritability estimates for IP than for the corresponding MT. The estimated genetic correlations between IP and MT (ra) were in general very high. A positive relationship (r = 0.57) between R2CV of calibration models and the estimated ra has been detected. For calibration models exhibiting R2CV higher than 0.75, ra were greater than 0.9. The variability in the estimated correlations increased when R2CV decreased, and for calibration models of moderate predictive ability, estimates of ra ranged from 0.2 to 1. Genetic parameter estimates suggested that IP can be used as indicator traits in breeding programs for the enhancement of fine composition and technological properties of milk. The genetic gain achievable selecting for IP is expected to be high for fatty acid composition, minerals, and for technological properties of milk, whereas it will be low for casein and whey protein composition and for the content of lactoferrin.

北海道産未利用原料を用いて設計された肥育期飼料給与が肥育豚の発育，産肉および脂肪組織の脂肪酸組成に及ぼす影響

北海道産未利用原料を用いた肥育期飼料給与が肥育豚の発育，産肉および脂肪組織の脂肪酸組成に及ぼす影響について，市販飼料給与区（対照区）と未利用原料を用いた試験飼料給与区（試験区）の2区を設定して検討した。試験飼料は乾物中粗タンパク質含量が市販飼料のそれと同量となるように，北海道産の規格外ジャガイモ（ジャガイモ）30.0%，廃棄された豆腐（豆腐）16.0%，アスパラガスの切り下（アスパラ）10.0%，商品とならない小麦粉（小麦粉）43.5%に市販のビタミン·ミネラル製剤0.5%を加えて配合した。なお，ジャガイモ，豆腐およびアスパラについては−30℃で凍結保存していたものを解凍·脱水処理後に60℃の送風乾燥機で乾燥し，風乾物として試験飼料の原料とした。給与試験には体重約76kgの三元交雑去勢豚（WLD）を用いた。その結果，発育成績および枝肉成績ともに両区間に有意な差は見られなかった。腎臓周囲脂肪および胸最長筋内脂質の脂肪酸組成は，C18:1の割合が対照区に比べ試験区で有意に低い値を示した（P<0.05）。また，C18:2とC18:3の割合が対照区に比べ試験区で有意に高い値を示した（P<0.01）。さらに，n-6/n-3比は対照区に比べ試験区で有意に低い値を（P<0.01），脂肪の硬軟を示すC18:2/C18:0比は対照区に比べ試験区で有意に高い値を示した（P<0.01）。一方，背脂肪および胸最長筋と頸棘筋間脂肪の融点は対照区に比べ試験区で有意に低い値を示した（P<0.01）。以上の結果から，養豚用飼料原料として活用されていないジャガイモ，小麦粉，豆腐およびアスパラを原料とした飼料を給与した豚は，市販飼料を給与した豚に比べ，脂肪中の多価不飽和脂肪酸が多くなることから，その融点は低くなり，若干脂肪は軟らかくなるものの，n-3系多価不飽和脂肪酸であるC18:3が増加し，その発育および産肉性も市販飼料給与豚と同等であることが確認できた。

ВИЯВЛЕННЯ ФАЛЬСИФІКАЦІЇ ЖИРОВОЇ СИРОВИНИ У ВИРОБНИЦТВІ КОМБІНОВАНИХ ХАРЧОВИХ ПРОДУКТІВ

Стаття присвячена проведенню газохроматографічного аналізу жирнокислотного складу різних видів жирів, які використовуються у виробництві кондитерських і хлібобулочних виробів. Визначення фальсифікації жирової сировини в борошняних кондитерських виробах проводили за жирнокислотним складом жиру після випікання. Для цього визначали жирнокислотний склад сировини, яка використовувалась, і його зміни уже в готовому продукті. Дослідження проводили з маслом селянським солодко вершковим з вмістом жиру 73% та маргарином столовим «молочним» жирністю не менше 82%. Особлива увага присвячена визначенню змін жиру, що відбуваються під час термічного оброблення. Крім того, наведено ряд кислот, які вказують на фальсифікацію сировини. На основі аналізу було ідентифіковано олії, які використовувались для приготування жирів, взятих на дослідження – кокосова, арахісова, соєва та соняшникова. Проведено удосконалення методики вилучення жиру з готового продукту. Основний зміст дослідження складає аналіз зміни жирнокислотного складу, що відбуваються після термічного оброблення. Результати дослідження висвітлюють, що кожному виду жиру притаманні свої індивідуальні зміни жирнокислотного складу Ця проблема мало вивчена і вимагає детальнішого дослідження.&#x0D;

Manipulation of milk fatty acid composition in lactating cows: Opportunities and challenges

Public health policies recommend a population wide decrease in the consumption of saturated fatty acids (SFA) to lower the incidence of cardiovascular and metabolic diseases. In most developed countries, milk and dairy products are the major source of SFA in the human diet. Altering milk fat composition offers the opportunity to lower the consumption of SFA without requiring a change in eating habits. Supplementing the diet of lactating cows with oilseeds, plant oils and marine lipids can be used to replace the SFA in milk fat with monounsaturated fatty acids (MUFA), and to a lesser extent, polyunsaturated fatty acids (PUFA). Due to ruminal metabolism, the decreases in milk SFA are also accompanied by increases in trans fatty acids (TFA), including conjugated isomers. The potential to lower SFA, enrich cis MUFA and PUFA, and alter the abundance and distribution of individual TFA in milk differs according to oil source, form of lipid supplement and degree of oilseed processing, and the influence of other components in the diet. The present review summarises recent evidence on changes in milk fat composition that can be achieved using dietary lipid supplements and highlights the challenges to commercial production of modified milk and dairy products. A meta‐analysis on the effects of oilseeds on milk fatty acid composition is also presented.Practical applications: Milk and dairy products are the major source of SFA in the diet in most developed countries. Including oilseeds, plant oils, and to a lesser extent, marine lipids in the diet of lactating cows can replace SFA with MUFA and PUFA in milk offering a mechanism to lower SFA consumption in human populations. Understanding the sources of variation in milk fat composition responses, and adjusting other ingredients in the diet to accommodate lipid supplements offers the opportunity to consistently produce milk with an altered fatty acid composition. However, commercialisation of dedicated supply chains will depend on whether the added costs of production and segregation of modified milk for processing can be recovered at retail.Dairy products are the major source of saturated fatty acids in diets of developed countries. There are various dietary strategies that can be employed at the dairy cow level to alter milk fat fatty acid composition, but it is important to understand variations in cow response to these interventions to consistently produce milk with altered fatty acid composition.

Changes in milk production and milk fatty acid composition of cows switched from pasture to a total mixed ration diet and back to pasture

This study evaluated the changes of cows’ milk fat fatty acids (FA) after transition from pasture to a total mixed ration (TMR) diet and back to pasture. Eight Holstein cows were used in a 52-d experiment divided into three periods. In period I (PI), cows grazed for 10 d and were supplemented with 5 kg head−1 day−1 of concentrate. On the 11th day, cows were moved to a barn and fed a TMR diet for the next 21 d (PII). On the 32nd day, cows were sent back to pasture for another 21 d (PIII) and received the same supplement of PI. Milk samples were taken on days 10 of PI and 2, 4, 7, 14 and 21 of PII and PIII. Total mixed ratio significantly increased dry matter intake and milk production and decreased milk fat content. Diet significantly affected the concentration of most FA in milk fat. Grazing pasture significantly increased the concentrations of 18:0, 18:1 c9, 18:1 t11, 18:2 c9,t11, 18:2 t11,c15, 18:3 c9,c12,c15, iso and anteiso branched-chain FA and sums of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). Concentrations of 12:0, 14:0, 16:0, 15:0, 17:0, 18:2 c9,c12 and the sum of saturated fatty acids (SFA) significantly increased with PII diet. Most FA and FA sums took 14–21 d to stabilise in PII and only 4–7 d after transition for pasture. This evolution pattern of milk fat FA suggests that the long historical feeding regimen is a factor that impacts on the time cows take to respond to different diets by changing FA composition, probably as a result of the adaptation time of rumen microbes.

Healthy Pork Production through Dietary n6:n3 Ratio Regulation

&lt;p&gt;The meat fat fatty acid composition could influent consumer health. Thus, this study was though dietary n-6:n-3 ratio regulation to production healthy pork. The experiment was used eighty LYD pigs that average weight was 66.5 kg (half male and half female) divide into five groups, they are lard group (L), soybean oil group (SO), commercial fish product group (CFP), canola oil group (CO), and 50% fish oil and 50% canola oil group (FCO) with 4 replicates, this experiment was lasted for 90 days. Experimental results indicated that the growth performances was no difference among groups; serum cholesterol, LDL and LDL-C were lower, meanwhile HDL was higher (P &amp;lt; 0.05) in FCO group than in control group. Back fat thickness, pork color, water holding capacity and meat fat content show no difference among groups. TBARS test on pork storage for 15 days in SO group was significantly higher (P &amp;lt; 0.05) than CO group. The n-6:n-3 ratio of back and belly fat in CFP, FCO and CO groups were significantly lower (P &amp;lt; 0.05) than in lard group. Panel evaluation score in SO group was significantly better (P &amp;lt; 0.05) than CO group in flavor, texture, juicy and total acceptance in longissmus muscle, but no difference in belly meat. In conclusion, the pork n-6: n-3 ratio was decreased with CFP, FCO, and CO supplementation, feeding pigs with low n-6:n-3 ratio fat could production healthy pork for consumers.&lt;/p&gt;

Re‐esterified oils from palm acid oil do not alter pork fatty acid composition

New fat products have been developed by chemically re‐esterifying acid oils (a by‐product of the food oil refining industry) with glycerol (a by‐product from biodiesel industry). These new products show lower free fatty acid content than acid oils and a fatty acid distribution within the positions of acylglycerols different from that of native oils. In this paper, we aim at assessing if the unique composition of re‐esterified palm oils (compared to native and acid oils) would affect pork and back fat fatty acid composition. A total of 24 pigs were fed one of the four experimental diets containing 4% experimental fat: native palm oil (PN), palm acid oil (PA), or two re‐esterified palm oils (PEL and PEH). Our results show that meat from pigs fed re‐esterified palm oils did not differ significantly in terms of total fatty acid and sn‐2 fatty acid compositions compared to PN or PA.Practical applications: Acid oils are by‐products of the food industry. They could be re‐utilized as feed ingredients but their free fatty acid content is usually high. High free fatty acid contents in diets have been related to low digestibility values when used in feed. New fat products have been developed by their chemical esterification with glycerol (a by‐product from biodiesel industry). Here, we have verified that these re‐esterified products would not alter pork fatty acid composition with respect to the use of native palm oil. Since results on productive parameters showed that they might increase feed efficiency and digestibility, overall the results support the re‐utilization of these fat by‐products in feed, alternative to the use of native palm oil or palm acid oil, provided that the benefits of the increase in feed efficiency counteract the cost of the esterification process.New fat products have been developed by chemically re‐esterifying palm acid oil (a by‐product of the palm oil refining industry) with glycerol. Compared to acid oils, they show a reduction of free fatty acids and an increase of partial acylglycerols. The fatty acid distribution within the positions of acylglycerols is different from that of native oils. This study has shown that their use in pig feed does not modify pork fatty acid composition compared to native or acid palm oil.

The effect of enzymatic interesterification on the physico-chemical properties and thermo-oxidative stabilities of beef tallow stearin and rapeseed oil blends

Beef tallow stearin (BTS) was blended with rapeseed oil (RSO) and the blends: 40 % BTS + 60 % RSO, 30 % BTS + 70 % RSO, 20 % BTS + 80 % RSO were interesterified using immobilized lipases from Rhizomucor miehei (Lipozyme IM) and Candida antarctica (Novozym 435) as the catalysts. The starting blends and the products of interesterifications were quantitatively separated into the triacylglycerol and non-triacylglycerol fractions containing free fatty acids (FFA) and of mono- and di-acylglycerols. It has been found that after interesterification the contents of the FFA and of MAG and DAG increased. The slip melting temperatures and solid fat contents of triacylglycerols separated from interesterified samples decreased if compared with non-esterified blends. The DSC melting profiles of the blends before and after interesterification were substantially different. The total fatty acid compositions of fats before and after interesterifications remained unchanged. Their distributions into sn-2 and sn-1,3 positions were close to random when Novozym 435 was used. When Lipozyme IM was used, the fatty acid composition at sn-2 position remained practically unchanged compared with the starting blend. Using the DSC and PDSC techniques, the oxidative stabilities of the fats before and after interesterification were also characterized. The interesterified blends were less resistant on thermo-oxidative degradation than the non-esterified ones.

Effects of extruded linseed on muscle physicochemical characteristics and fatty acid composition of lambs

Effects of extruded linseed incorporation on meat quality and intramuscular fat fatty acids (FAs) composition were studied on 36 lambs from Tunisian local breed, Queue Fine de l'Ouest. All lambs were male with an average body weight of 21.3 kg at the beginning of the experiment. Animals were divided into three groups of 12 lambs each, receiving hay ad-libitum and one of three concentrates containing 0 (Control), 15 (L15) and 30 (L30) per cent of extruded linseed. At the end of the experiment which lasted for 85 days, all the lambs were slaughtered. Samples of longissimus dorsi muscle were taken for meat quality measurements and FA determination. No effects of linseed on lamb growth were observed. The cooking loss, meat pH and colour parameters were similar for all diets. Linseed supplementation increased protein content (p=0.07) and decreased fat content (p=0.06) in the meat. However, the intramuscular FA composition was affected by linseed supplementation. The polyunsaturated FA to saturated FA ratio (PUFA/SFA) was higher for L15 and L30 groups than for Control (p<0.01). The content of C18:3 and the sum of polyunsaturated FA (PUFA) were higher for L15 and L30 groups than for Control one (p<0.05). PUFA n−3 contents significantly increased with linseed incorporation (0.70, 3.56 and 3.26 for Control, L15 and L30, respectively). In contrast, n−6:n−3 ratio significantly decreased from 5.23 for Control to 0.71 and 1.1 for L15 and L30, respectively.