Chemical and Physical Characterization of Donkey Abdominal Fat in Comparison with Cow, Pig and Sheep Fats

The objective of this research was to investigate the physicochemical properties of donkey fat. Results show that donkey fat contains 59.38 % unsaturated fatty acids, 38.37 % saturated fatty acids, and 0.21 % trans fatty acids. The sn-2 monoglyceride present in donkey fat contain 67.91 % unsaturated fatty acids and 30.97 % saturated fatty acids. Donkey fat is also characterized by a total tocopherol content of 8.59 mg/100 g fat (7.90 mg/100 g fat α-tocopherol, 0.51 mg/100 g fat β + γ-tocopherol, and 0.18 mg/100 g fat δ-tocopherol), 0.0032 mg/100 g fat cholesterol, an acid value of 0.091 KOH (mg/g), an iodine value of 76.47 g/100 g, a peroxide value of 0.68 mmol/kg, a saponification value of 193 mg/g, a refractive index of 1.4666, and a specific gravity of 0.9144. The complete melting temperature was 40 °C. The content of unsaturated fatty acids (total and sn-2) in donkey fat is higher than cow, pig and sheep, while the content of trans fatty acids is lower. The tocopherol content is also higher in donkey fat compared to cow, pig and sheep fat. Interestingly, the fat with such processing has nearly no cholesterol. Generally speaking, donkey fat could be a good animal fat for human consumption.     

Buffalo meat composition as affected by different cooking methods

Buffalo meat is considered in Italy as an alternative product for its good nutritional characteristics. The influence of three cooking methods (boiling, grilling and frying) on the chemical and lipid composition of buffalo meat was evaluated. All the treatments reduced the moisture and increased protein, ash and fat content. The increase in fat content was higher after frying due to the incorporation of fat from olive oil. Fried meat had lower saturated fatty acid content due to the incorporation of mono-unsaturated (C18:1) fatty acids from oil. The incorporation of oil fatty acids caused a decrease in conjugated linoleic acid relative content. Moreover, fried meat showed the highest levels of the unhealthy trans fatty acids. Therefore, frying was shown as the worst cooking methods regarding human health. Boiling and grilling increased thiobarbituric acid reactive substances, while frying had no effect on them.     

Comparison of total fat,fatty acids,cholesterol, and other sterols in mayonnaise and imitation mayonnaise

Nine brands of mayonnaise and five brands of imitation mayonnaise were purchased from supermarkets in the Washington, DC, area. The samples were analyzed for total fat, fatty acids, sterols, and moisture. Little variation in total fat and saturated fatty acid values was observed among the brands of mayonnaise. The polyunsaturated fatty acid content of mayonnaise ranged from 28.0 to 47.9 g/100 g product. The cholesterol levels were divided between two ranges, 50-55 and 75-79 mg/100 g product. In contrast, there was wide variation in the lipid composition of the different brands of imitation mayonnaise. The total fat values for these products varied from 14.3 to 50.4 g/100 g product. The cholesterol content varied between 0 and 72 mg/100 g product; the latter figure equals the cholesterol content of many of the mayonnaise samples.     

Utilization of high‐oleic rapeseed oil for deep‐fat frying of French fries compared to other commonly used edible oils

Changes in chemical, physical and sensory parameters of high‐oleic rapeseed oil (HORO) (NATREON?) during 72 h of deep‐fat frying of potatoes were compared with those of commonly used frying oils, palm olein (PO), high‐oleic sunflower oil (HOSO) and partially hydrogenated rapeseed oil (PHRO). In addition to the sensory evaluation of the oils and the potatoes, the content of polar compounds, oligomer triacylglycerols and free fatty acids, the oxidative stability by Rancimat, the smoke point and the anisidine value were determined. French fries obtained with HORO, PO and HOSO were still suitable for human consumption after 66 h of deep‐fat frying, while French fries fried in PHRO were inedible after 30 h. During the frying period, none of the oils exceeded the limit for the amount of polar compounds, oligomer triacylglycerols and free fatty acids recommended by the German Society of Fat Science (DGF) as criteria for rejection of used frying oils. After 72 h, the smoke point of all oils was below 150 °C, and the amount of tocopherols was reduced to 5 mg/100 g for PHRO and 15 mg/100 g for HORO and HOSO. Remarkable was the decrease of the oxidative stability of HOSO measured by Rancimat. During frying, the oxidative stability of this oil was reduced from 32 h for the fresh oil to below 1 h after 72 h of frying. Only HORO showed still an oxidative stability of more than 2 h. From the results, it can be concluded that the use of HORO for deep‐fat frying is comparable to other commonly used oils.     

Stability of fat‐soluble vitamins and PUFA in simulated shallow‐frying

Fat‐soluble vitamins and essential polyunsaturated fatty acids (PUFA) are nutrients that are sensitive to heat treatment and oxidation and therefore can be partly lost during cooking. It is well‐documented that a long‐term deep‐frying process leads to a substantial degradation of PUFA and vitamins in a frying medium. In this study, the stability of vitamins and fatty acids was investigated in a series of liquid margarines (82% fat) varying in fat blend and the content of minor components. The tested samples were subjected to the standardised treatment that has been developed to mimic shallow‐frying of food at 180°C and the recovery of individual nutrients is reported. The results show that fat‐soluble vitamins possessed reasonable stability under the condition of the shallow‐frying test. Essential PUFA of the frying medium were hardly affected by the treatment. Overall evaluation of the results suggests that oil‐based cooking media rich in vitamins and PUFA have a positive impact on nutritional value of food prepared by appropriate means of cooking.     

Frying performance of a sunflower/palm oil blend in comparison with pure palm oil

The aim of this study was to test the performance of a vegetable oil blend formulated as alternative to pure palm oil as frying medium. For this purpose, the evolution of many analytical parameters (free acidity, spectrophotometric indices, total polar components, fatty acid composition, short‐chain fatty acids, tocopherol and tocotrienol content and composition, color, flavor evaluated by means of an electronic nose) of the selected blend (sunflower/palm oil 65 : 35 vol/vol) has been monitored during a prolonged frying process (8 h discontinuous frying without oil replenishment) in comparison to pure palm oil. Sensory attributes of the fried food were also evaluated. The blend proved to keep qualitative parameters comparable to those shown by palm oil during the prolonged frying process. Even if some oxidation indices, such as spectrophotometric indices, short‐chain fatty acids and total polar components, increased faster in the blend, it showed a higher tocopherol content and a lower increment in free fatty acids as compared to pure palm oil. Chips fried in the two oils did not show significantly different sensory profiles.     

Substitution of trans fatty acids in foods on the Danish market

Three surveys of the content of trans fatty acids (TFA) in foods on the Danish market were carried out before and after the Danish regulation was introduced in January 2004 restricting the use of industrially produced (IP)‐TFA to a maximum of 2 g per 100 g fat in any food product. For this purpose, food samples were collected in 2002–3, 2004–5, and 2006–7. Of these, 60 paired samples (defined as samples included in two of the three investigations and with higher levels of IP‐TFA in the first determination than in the second) were identified. Comparisons of the fatty acid profiles showed that, in 68% of the products (e.g. sweets, cakes and cookies as well as fast food such as pie and tortilla), IP‐TFA were mainly substituted with saturated fatty acids (SFA). In some cases, the SFA source was coconut fat, whereas in other products, palm oil was added instead of partially hydrogenated oils. However, in important cases like frying fats, healthier fat substitutes with monounsaturated fatty acids were used. The surveys showed that the IP‐TFA content has been reduced or removed from most products with originally high IP‐TFA content, like French fries, microwave oven popcorn and various bakery products, so that IP‐TFA are now insignificant for the intake of TFA in Denmark.     

Effect of Different Frying Methods on the Total <Emphasis Type="Italic">trans</Emphasis> Fatty Acid Content and Oxidative Stability of Oils

The main objective of this study was to determine the effect of different frying oils and frying methods on the formation of trans fatty acids and the oxidative stability of oils. Sunflower, canola and commercial frying oils, the most commonly used oils for frying potatoes in the fast food industry, were used as the frying medium. The value for total polar compounds was highest when commercial frying oil was used in the microwave oven (22.5 ± 1.1). The peroxide value, as an indicator of oil oxidation, was lowest for microwave oven frying (2.53 ± 0.03). The K₂₃₂ and K₂₇₀ values were 0.41 ± 0.04 and 0.18 ± 0.02, respectively, for commercial frying oil in the microwave oven. The lowest free fatty acid content was recorded for the commercial frying oil used in the deep‐fat fryer at 190 °C. The highest iodine value was measured for sunflower oil used in the deep‐fat fryer (148.14 ± 0.07), indicating a greater degree of unsaturation. The lowest trans fatty acid value was recorded for sunflower oil in the microwave oven (0.17 ± 0.05), with a higher overall amount of total trans fatty acids observed for oils after frying in the electrical deep‐fat fryer compared to the microwave. Sunflower oil was favourable for both frying methods in terms of the trans fatty acid content.     

Studies on some Hungarian Fats and Oils Obtained from Commercial Frying Processes

Commercial frying oil and fat samples (lard and sunflower) were collected during a survey on operating conditions and quality of frying fats, conducted in Hungary. The major fatty acids as well as some important types of alteration products (polar components, polymers and cyclic fatty acid monomers) were determined in each sample. The contents of the polar components ranged from 6.8 to 24.4% for the lard samples and from 4.4 to 49.9% for the sunflower oil samples. Values for polymers ranged from 1.0 to 1.5% for the lard samples and from 3.5 to 21.5% for the sunflower oil samples. Only minor amounts of cyclic monomers were found in both types of fats (ranging from 0.03 to 0.16%). The most abused sunflower oil and lard samples were fractionated into their main groups of components and the percentages of the different frying fat constituents were determined.     

Fatty acid components of fried foods and fats used for frying

Oxidation of fat is accelerated at temp as high as those used for frying. The extent of this oxida-tion has been studied by frying two kinds of foods (chicken or potatoes) in cottonseed oil and in lard. Fat samples, taken prior to use and follow-ing 5 and 10 hr of frying (both for chicken and potatoes) were esterified. Subsequent quantita-tive assays of methyl esters by gas chromatogra-phy showed that the linoleic acid content had decreased from 57-49% after cottonseed oil had been used 10 hr for frying. This decrease was present regardless of whether chicken or potatoes were fried. There was no change in the linoleic acid content of lard after chicken was fried, but a decrease from 11.3-5.8% was noted when pota-toes were fried for 10 hr. The fatty acid content of the fat extracted from the potatoes and the fat used to fry them, was the same when sampled at 5 hr. However, at the end of the 10-hr frying period, fat ex-tracted from the potatoes had a lower linoleic acid content than fat used to fry them. Results were the same for both cottonseed oil and lard. Fatty acid components of the fat extracted from the chicken seemed to be affected as much by the fatty acid composition of the chicken itself as by fat used for frying. Whether the chicken was cooked in fat used 5 or 10 hr made little differ-ence. Journal Paper No. 1130, Mississippi Agricultural Experiment Station. A portion of the work in this paper is taken from a thesis sub-mitted in partial fulfillment of the requirements for the Master of Sci-ence degree at Mississippi State University in January, 1963.     

Mold induced changes in cacao lipids

The free fatty acid content of sound cacao beans of nine geographic orgins varied from 2.7 to 4.8 meq./100 g fat. Fungi grown on cacao beans under humid environmental conditions have remarkable lipolytic activity. Values as high as 200 meq. free acid/100 g fat were obtained for badly deteriorated samples. Titration of the free fatty acids of cacao fat is suggested as a simple control procedure for detecting cocao butter obtained from moldy beans. Percentage composition of the free fatty acid fraction changes as a result of mold growth. Stearic and palmitic acid increased while oleic and linoleic acids decreased. Tracer experiments show no observable conversion of oleic acid to stearic. The changes suggest oxidative reactions to form carbonyl compounds.     

The Impact of Fat Deterioration on Formation of Acrylamide in Fried Foods

The current study investigates to what extent the reaction products of thermal degradation directly influence acrylamide formation in French fries. The frying tests at 170 and 180 °C are carried out with rapeseed oil for 32 h with 128 frying cycles. Acrylamide content in French fries is determined by LC-MS/MS. Oxidative and thermal degradation is followed by measuring total polar compounds (TPC), di- and polymerized triacylglycerols (DPTG), monomer oxidized triacylglycerols (MONOX), p-anisidine value (AnV), mono and di-acyl-glycerols (MAG and DAG), acid value (AV), epoxy fatty acids, iodine value (IV), saponification value, and fatty acid composition. During frying, the nature and degradation level of the frying medium have a direct impact on acrylamide formation. It can be shown that the pH-dependent reaction is strongly inhibited at acid values above 0.5 mg KOH g⁻¹ oil. Acidity measured as AV or FFA is mainly caused by oxidation, and less so by hydrolysis of triacylglycerols (TAG) as assumed up to now. Obviously, acid functional groups formed by oxidation of unsaturated fatty acids bound in TAG can act not only as catalyst for dimerization of TAG but also interact with asparagine as most important precursor for acrylamide formation so that no reaction with carbonyl groups for the formation of acrylamide is necessary. Practical applications: The same acidic functional groups that are known to catalyze the formation of dimeric TAG under frying conditions (160–190 °C, access of oxygen) in a nonradical mechanism apparently can also deactivate asparagine by protonization as a potential precursor for the formation of acrylamide. It is recommended not to reduce acidity of used frying oil by active filter aids below AV ≥ 0.5 as it helps to reduce acrylamide contamination of fried food.     

Effects of frying on the trans‐fatty acid formation in soybean oils

To evaluate the effects of repeated deep‐frying on the trans‐fatty acid (TFA) formation in soybean oils, simultaneous frying experiments were carried out. French fries were prepared using three different types of soybean oil (pressed soybean oil, PSBO; first‐grade solvent extracted soybean oil, FG‐SESBO; and third‐grade solvent extracted soybean oil, TG‐SESBO). French fries were fried intermittently at 180–185°C for a total frying time of 32 h and at an interval time of 30 min. It was found that the initial amount of total TFAs was 0.29 g/100 g, 0.31 g/100 g, and 0.90 g/100 g in PSBO, TG‐SESBO, and FG‐SESBO, respectively. Before the frying started, the C18:1,t‐9, trans‐linoleic acid (TLA), trans‐linolenic acid (TLNA), and total TFA content of the PSBO and TG‐SESBO were significantly lower than in the FG‐SESBO (p<0.05). However, in the frying oil samples, the final concentration of total TFA in the PSBO, TG‐SESBO, and FG‐SESBO were 1.79 ± 0.17 g/100 g, 1.12 ± 0.10 g/100 g, and 1.70 ± 0.07 g/100 g, which was 6.17‐, 3.61‐, and 1.89‐fold higher that in fresh oil, respectively. The highest increasing slopes of C18:1,t‐9, TLA, TLNA, and total TFA were observed in the PSBO. Practical applications : A high intake of TFAs has been shown to lead to an increased risk of coronary heart disease. Plant oils, particularly soybean oil, have been widely used in the food industry in China. Frying is one of the most common methods to cook food. The formation of TFAs during frying has been shown to be closely related to the temperature and duration of the frying process. However, the effects of frying on the formation of TFAs in different soybean oils have not been well studied. In the present study, we demonstrated that increasing the number of frying cycles can cause an intensive increase in the concentration of TFAs in different types of soybean oil, but especially in PSBO.     

α-Linolenic Acid Transfer into Milk Fat and its Elongation by Cows

It was the purpose of this study ot explore to what extent α-linolenic acids transferred into bovine milk fat if either fed as intact linseed or if infused as linseed oil (α-linolenic acid content ≈? 55 wt%) into the abomasum. Two cows consumed 2000 g/d linseed for 9wk. Then two doses of linseed oil (500 or 250 g/d) were infused for 14 or 4 wk into the abomasum of the cows, respectively. There was no effect of linseed oil on milk production, milk fat and protein content, whereas linseed caused a slight decline of milk protein content simultaneously with a pronounced rise of trans fatty acids in milk fat. While during the linseed period only 1% of consumed α-linolenic acid (C18:3n-3) appeared in milk fat, on average 49 or 56% of infused C15:3 was transferred into milk fat depending on the infusion rate of linseed oil. There was only modest rise of about 0.25 wt% of desaturation/elongation metabolites (C20:5 plus C22:5) of α-linolenic acid in milk fat indicating a low δ⁶-desaturase activity of the cow. Docosahexaenoic acid (C22:6) was not found in milk fat. It is concluded that bovine lipid metabolism allows surprisingly high transfer rates of n-3 fatty acids of linseed oil into milk fat and that there is the possibility to enrich milk fat with n-3 fatty acids without affecting milk yield provided ruminal biohydrogenation is prevented.     

Nutritional and microbiological profile of soybean sausages available in Costa Rica

The nutritional and microbiological quality of 80 soybean sausage samples (50% frankfurter and 50% sausage mortadela) was studied. On average, the protein content was 17.5 g/100 g in sausage mortadela and 20 g/100 g in frankfurter. The mean total fat content was 5.5 g/100 g for both products. However when products of different manufacture industries were compared, a highly significant difference (p = 0.0000) in the fatty acids speciation between both groups and between samples of the same product were found. Bigger differences were found in the content of palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2). Cholesterol was not detected in samples analyzed. On average the atherogenicity index was 0.55 for sausage mortadela and 0.59 for frankfurter. A consumption of 25 grams of of soybean protein from these sausages can bring an intake of saturated fatty acids between 20-90% of the daily recommendation. Likewise, they can supply between 12-70% of the recommended daily polyunsaturated fatty acids. These variations are owing to the big difference in fatty acids speciation in each sausage brand. Around 20% of soybean sausages studied showed total coliform levels above 10(4)/g, being more frequent in sausage mortadela. Also 60% of this product and 10% of frankfurters showed psychrotroph levels of 10(6)/g. Clostridium perfringens, in levels above 10(2)/g was evidenciated in 5% of samples, Escherichia coli was not isolated from them. The findings of this study suggest the urgent need for implementing a quality control system for soybean sausages, before national health authorities consider to support nutritional campainings that promote their consumption.     

Fettsäurenaufnahme des Menschen und Möglichkeiten der Beeinflussung durch die Tierernährung

Fatty acid intake of men and possibilities to influence the intake by animal nutrition. About 70% of total fat intake (≈ 100 g per person per day) are from fat of animal origin in Germany. Animal nutrition may influence fat content and fatty acid pattern in animal products. This paper summarizes the influence of feeding on fatty acid pattern of meat (pork, beef, poultry, rabbit, fish), milk and eggs. Fatty acid intake is demonstrated under consideration of fat intake of men and variation of fatty acid pattern of various fats of animal origin. Daily fat intake of men amounted to 43 g saturated, 37 g monoen and 13 g polyen fatty acids. It may vary between 38 and 46 g saturated, 33 and 45 g monoen and 11 and 17 g polyen fatty acids if variation of fatty acid pattern of animal fats is considered. By combination of lower fat intake and changed fatty acid pattern of animal products fatty acid intake may be changed to more monoen and polyen fatty acids.     

Nutritional characterization of produced fish for human consumption in Bucaramanga, Colombia

This research involves the nutritional characterization of the most commonly cultivated fish in the region. The species under study were: Rainbow trout (Salmo gairdnerii), tilapia roja (Oreocliromis sp), cachama blanca (Piaractus brachypomus), bocachico (Prochilodus reticulatus magdalenae) and catfish (Pseudoplatystoma faciatum). A sea fish, coho Salmon (Oncorhynchus kisutch), was used as reference because it is the imported species most used in the region, and it also contains n-3 fatty acids. For each fish sample moisture, ash, protein content, total fat, minerals (iron, calcium and phosphorous) and a fatty acid profile were determined. Results show a total protein content in between 16.4 and 22.6 g/100 g fillet for fresh water fish. Total fat amounts for trout are the highest (8.1 g/100 g fillet), while catfish has the lowest fat content (0.4 g/100 g fillet). Trout was found to be the most important source of n-3 fatty acids (EPA+DHA) and phosphorous, with values ranging from 0.25% to 0.52%, and 250 to 346 mg/100 g fillet, respectively. Catfish and trout exhibited the highest iron content, with values ranging from 3 to 6mg/100 g fillet. Salmon, on the other hand, showed a high n-3 fatty acid content of 1.16% to 2.25%, when compared to fresh water fish. Calcium content is low in all species under scrutiny. Fresh water fish, other than trout, show no significant amount of n-3 fatty acids. However, all of them are a good source of protein. The obtained results allowed to determine the profile of oily acids of produced fish for human consumption in the region, demonstrating that the trout is the species with major quantity of oily acids n-3 specially DHA and of the minerals the phosphorus. Other species (kinds) catfish, bocachico, tilapia and cachama, are not a source of oily acids n-3, but they are an important source of protein.     

Factors Impacting the Formation of 3-MCPD Esters and Glycidyl Esters During Deep Fat Frying of Chicken Breast Meat

The effect of the frying temperature, frying duration and the addition of NaCl on the formation of 3‐monochloropropane‐1,2‐diol (3‐MCPD) esters and glycidyl esters (GE) in palm olein after deep frying was examined in this study. The eight frying systems were deep‐fat frying (at 160 and 180 °C) of chicken breast meat (CBM) (with 0, 1, 3 and 5% sodium chloride, NaCl) for 100 min/day for five consecutive days. All oil samples collected after each day were analyzed for 3‐MCPD ester, GE, and free fatty acid (FFA) contents, specific extinctions at 232 and 268 nm (K₂₃₂ and K₂₆₈), p‐anisidine value (pA), and fatty acid composition. There was a significant (p < 0.05) decrease in the 3‐MCPD esters and a significant (p < 0.05) decrease in the GE with the increasing of the frying duration. There were significant (p < 0.05) increases in the 3‐MCPD esters formed when the concentration of NaCl increased from 0 to 5%. The addition of NaCl to the CBM during deep frying had no significant effect on the GE generation. The FFA contents, K₂₃₂ and K₂₆₈ and pA showed that all the frying oils were within the safety limit.     

Quantitation and distribution of altered fatty acids in frying fats

The distribution and quantity of polar compounds and altered fatty acids in used frying oils, collected by Food Inspection Services of the Junta de Andalucía in Spain, was measured. Additional samples evaluated were sunflower oil, high-oleic sunflower oil, and palm olein that were subjected to thermoxidation and frying in laboratory experiments. A combination of adsorption and high-performance size-exclusion chromatography was applied to the oil samples both before and after transesterification. Through analysis of fatty acid methyl ester derivatives, differentiation of four groups of altered fatty acids (oxidized monomers, nonpolar dimers, oxidized dimers, and polymers) could be attained. Evaluation of real frying samples with polar compound levels around the limit for fat rejection (21.1–27.6% polar compounds) gave values of total altered fatty acids ranging from 8.1 to 11.3%, and levels higher than 20% were found in the most degradated samples. The results obtained clearly support the need for control and improvement of the quality of used fats in fried-food outlets.     

Effects of milk fat replacement by PUFA enriched fats on n‐3 fatty acids,conjugated dienes and volatile compounds of fermented milks

A study was carried out to determine the profiles of fatty acids in fermented milks and dairy derivatives made with milk fat substituted by polyunsaturated fatty acid (PUFA)‐enriched fat. In order to improve the organoleptic properties of those products, whey protein concentrates (WPC) were added during the manufacturing process. Interest was focused during manufacturing and storage period on the contents of “healthy” fatty acids, mainly conjugated linoleic acid and n‐3 PUFA. Contents of these fatty acids were not affected by the manufacture practices and neither did addition of WPC during manufacturing nor cold storage cause their decrease. Percentages of total n‐3 fatty acids in fat from dairy derivatives enriched in PUFA after 21 d of storage (1.45%) were very close to those obtained before processing (1.39%). Contents did not differ either substantially when WPC were added during manufacturing (1.46%). The increase of volatile compounds was also examined. Although a slight decrease in the total volatile content was observed, percentages of different compounds were not modified when milk fat was substituted by PUFA enriched fat.