Variability in the intercomparison of food carotenoid content data: A user's point of view

The availability of reliable information on food composition is essential both for the evaluation of diet and for nutritional research to relate diet to health or disease. In this article, we compare the total and individual carotenoid contents and the retinol equivalents in fruits and vegetables reported in several food composition tables and HPLC studies. The impact of the variability in carotenoid intake was evaluated on the basis of Spanish National Consumption Statistics and on the values for a standard diet. We identify, from a user's point of view, errors concerning identification of the items and the terms used to refer to the compounds. Food composition tables overestimate (by 2 to 48%) the retinol equivalent intake, whereas they underestimate (by 30 to 50%) the total carotenoid intake according to HPLC data. We study the effect of these main sources of error, their impact on dietary assessment and on the classification of relevant contributors, and the possible consequences with respect to proper diet in terms of nutritional assessment and epidemiological studies. Given the different dietary habits among populations and the fact that certain items may be over‐ or underestimated in databases, the use of a single database may be misleading as to the rate of carotenoid consumption and the “true” nutrient intake in a given population, thus weakening the reliability of the study and resulting in erroneous conclusions.     

Effect of food matrix and heat treatment on the rheological properties of salmon-based baby food

Shelf stable baby foods from Alaskan salmon were developed from red and pink salmon with and without bones. The effect of salmon type, presence of bones and thermal treatment (121 °C for 55 min) on the dynamic (viscoelastic) and flow models were evaluated. Rheological behaviors of all samples were also tested over a temperature range of 25–55 °C. All samples had a higher viscoelastic behavior with consistently higher storage modulus (G′) than loss modulus (G″) over the entire frequency range used (0.5–100 rads/s at 25 °C). Thermal treatment had a significant effect (p < 0.0001) on viscoelastic behavior of baby foods when the exponential model (G′ or G″ = A(ω)^b) was used. A values were higher for the processed food for G′ and G″, and b values. The Casson model was found to be the best for the shear rate – shear stress for all types of tested samples. Retorted samples exhibited lower yield stress than their unretorted counterparts. Retorted samples were susceptible to temperature change more than unretorted samples as shown by energy of activation values (E_a) when the effect of temperature (25–55 °C) was studied with an Arrhenius type model. Red salmon without bone had higher E_a values among all samples and with pink salmon with bone recording a lowest among all of them.     

Physical and nutritional properties of baby food containing menhaden oil (Brevoortia tyrannus) and microencapsulated menhaden oil

Purified menhaden oil (PMO) was characterized and microencapsulated. Baby foods containing PMO and microencapsulated purified menhaden oil (MPMO) were evaluated and compared. PMO had higher total omega-3, total saturated, total monounsaturated, DHA, and EPA contents than MPMO. Emulsion containing PMO (EPMO) exhibited viscoelastic characteristic and droplet size of EPMO was around 2-10 μm. The DHA and EPA in the PMO were reduced in MPMO. All baby-food samples with added fish oils had similar FFA values and color. DHA and EPA of baby food were significantly increased by adding PMO and/or MPMO. Total percent values for omega-3 fatty acids of extracted fat from commercial baby food (CB), commercial baby food containing PMO (BPMO), and commercial baby food containing MPMO (BMPMO) were 4.5, 9.8 and 10.1%, respectively.     

Dissipation kinetics of fluquinconazole and pyrimethanil residues in apples intended for baby food production

Dissipation behaviour of simultaneously applied fungicides fluquinconazole and pyrimethanil was studied in/on apples intended for baby food production (cultivars Jonagold Decosta, Golden and Champion). The apples were sprayed at two dosages to control the pathogen Venturia inaedequalis (Cooke) Aderh. A validated gas chromatographic method (GC-ECD and GC-NPD) was used to determine the fungicides residues, the analytical performance of which was highly satisfactory with expanded uncertainties not higher than 15% (coverage factor k = 2, confidence level 95%) The dissipation of the fungicide residues was fitted to the experimental data assuming pseudo first-order decay kinetics (R² between 0.897 and 0.992). To obtain the fungicide residues below 0.01 mg/kg, which is the default maximum residue level for food intended for infants and young children, the application of the fungicides under study should be carried out 2 or 3 months before harvest at the lower (1.0 L/ha) and the higher (1.5 L/ha) recommended dose, respectively.     

Identification and quantification of carotenoids by HPLC-DAD during the process of peach palm (Bactris gasipaes H.B.K.) flour

The identification and quantification of carotenoids has been carried out on tropical and non tropical fruits because of two important carotenoid's properties: as antioxidant compounds having a prevention role in some diseases, and as a source of provitamin A needed for a good human nutrition. This study aimed to identify carotenoids present during different steps for producing flour from Costa Rican peach-palm fruit (Bactris gasipaes H.B.K). Nine carotenoids were tentatively identified and quantified by HPLC-DAD in raw pulp, and 14 were detected in cooked pulp, the additional five being products of isomerization and hydroxylation of carotenoids in the raw pulp. The flour contained 13 carotenoids, one less (all-trans-??-criptoxanthin) than in cooked pulp, with the main one being all-trans ??-carotene. This carotenoid was also present in raw pulp at a concentration of 96.0 ± 1.7 ??g equiv. of ??-carotene g⁻¹ dw. The concentration decreased significantly (P < 0.05) during cooking and drying to reach a final concentration of 33.3 ± 1.0 ??g equiv. ??-carotene g⁻¹ dw in the flour. Flour production reduced (P < 0.05) the total carotenoid content from 373.4 to 237.7 ??g of ??-carotene g⁻¹ dw, with a final retention rate of 63.7% by the end of the process. Moreover, 9 of the 14 carotenoids account for high levels of provitamin A, which, even so, had decreased from 2723 retinol equivalents (RE) 100 g⁻¹ in raw pulp to 1614 RE 100 g⁻¹ in cooked pulp and 1289 RE 100 g⁻¹ in flour. Provitamin A level is still high when compared to other common provitamin A sources. Our study shows that while there is a change in the levels and profile of carotenoids during the peach-palm flour process, and a reduction of provitamin A value, peach-palm fruit is a great source of bioactive compounds.     

Physicochemical characteristics of weaning food formulated from different blends of cereal and soybean

 The physicochemical characteristics of porridges of adult and infant weaning food prepared from fermented blends of cereals and soybean are reported in this study. The pH of the formulated flour blends was less than 5.0 within 12 h of fermentation with F15B and F410B, attaining a pH of 3.4. Titratable acidity, which was not detected in unfermented samples, increased as the fermentation progressed. An increase in the gross energy content was noted with F25B, yielding a value of 439.0 kcal/100 g. All the fermented flour blends reconstituted well in boiling water and the water-holding capacity also increased. There was a slight difference in the bulk densities of the loose and packed flour. The index of gelatinization of unfermented formulated flour ranged from 82 (B. U.) in F15A to 334 (B. U.) in F310A. However, there was an increase in the values of the index of gelatinization of the blends at the end of the fermentation. All the blends had relatively low viscosities except F310B. Based on the parameters considered in this study, F15B is recommended as a potential infant and adult food. Received: 10 June 1996 / Revised version: 17 September 1997     

Formation of furan in baby food products: Identification and technical challenges

Furan is generally produced during thermal processing of various foods including baked, fried, and roasted food items such as cereal products, coffee, canned, and jarred prepared foods as well as in baby foods. Furan is a toxic and carcinogenic compound to humans and may be a vital hazard to infants and babies. Furan could be formed in foods through thermal degradation of carbohydrates, dissociation of amino acids, and oxidation of polyunsaturated fatty acids. The detection of furan in food products is difficult due to its high volatility and low molecular weight. Headspace solid-phase microextraction coupled with gas chromatography/mass spectrometer (GC/MS) is generally used for analysis of furan in food samples. The risk assessment of furan can be characterized using margin of exposure approach (MOE). Conventional strategies including cooking in open vessels, reheating of commercially processed foods with stirring, and physical removal using vacuum treatment have remained unsuccessful for the removal of furan due to the complex production mechanisms and possible precursors of furan. The innovative food-processing technologies such as high-pressure processing (HPP), high-pressure thermal sterilization (HPTS), and Ohmic heating have been adapted for the reduction of furan levels in baby foods. But in recent years, only HPP has gained interest due to successful reduction of furan because of its nonthermal mechanism. HPP-treated baby food products are commercially available from different food companies. This review summarizes the mechanism involved in the formation of furan in foods, its toxicity, and identification in infant foods and presents a solution for limiting its formation, occurrence, and retention using novel strategies.     

Determination of fungicide residues in baby food by liquid chromatography-ion trap tandem mass spectrometry

Current European Commission Directives on foods for infants and young children places emphasis on the control of pesticide residues at levels below 10 μg kg(-1). In the present work, a liquid chromatography electrospray ionisation ion trap tandem mass spectrometry (LC-Ion Trap-MS/MS) has been developed for the multiresidue of 10 multiclass fungicides (carbendazim, thiabendazole, imazalil, tridemorph, triadimefon, bitertanol, prochloraz, flutriafol, myclobutanil and diphenylamine) in fruit-based baby food. The developed method is based on a simple sample treatment (QuEChERS), which consists of a liquid-liquid extraction using acetonitrile, followed by a clean-up step based on dispersive solid-phase extraction with primary secondary amine (PSA). Subsequent identification and quantitation was accomplished by liquid chromatography/electrospray tandem mass spectrometry using an ion-trap mass spectrometer in the product ion scan MS/MS mode. Matrix effects were evaluated in LC-MS and LC-MS/MS mode experiments, obtaining a reduction of these effects when working in MS/MS mode for most of the analytes. Limits of detection (LOD) were between 0.5 and 3.0 μg kg(-1) depending on the pesticide studied, all being within European Union regulations for baby food. Finally, the proposed method was applied to 25 baby food samples obtained from local supermarkets. Imazalil, thiabendazole and carbendazim were detected in the studied samples. However, none of the samples tested were found to be upper the EU standard.     

An enzymatic method for the determination of fructans in foods and food products

 We report a new and non-equipment demanding method of measuring the content of fructans as well as the contents of free glucose, free fructose and sucrose in foods and food products enzymatically. This method comprises hydrolysis of fructans into d-glucose and d-fructose enzymatically and measurement of the released sugars enzymatically. Sucrose is hydrolysed by α-glucosidase instead of β-fructosidase, which is normally used. In addition, sucrose is measured in the form of d-fructose instead of the typical d-glucose form, and the fructanase used to hydrolyse the fructans has fewer side effects than the fructanase reported as normally used. The method is tested on ten standard substances and five fructan products, and nine foods and food products are also analysed. The enzymatic measurement of the released sugars is confirmed by measurements done by high performance anion exchange chromatography with pulsed amperemetric detection. Received: 1 March 1999 / Revised version: 23 April 1999     

Sodium, potassium, calcium and magnesium content in breakfast cereals: products highly consumed by the spanish population

 In this work is presented a study of the sodium, potassium, calcium and magnesium contents in 15 samples of the breakfast cereals that are most consumed by the Spanish population. We have found that they are of varied compositions, both in relation to the number of cereals which are the basis of their formulations, and to the rest of the ingredients added to enrich these products. This results in a wide variation in the macroelements contents, although all are found in significant quantities. In all samples, sodium was the predominant cation, reaching levels above 800 mg/100 g, and magnesium was the most scarce cation, with values ranging between 7 mg/100 g and 67 mg/100 g. Potassium and calcium also varied greatly, the former particulary in those breakfast cereals which contained wheat, and the latter in those enriched with milk or calcium salts. Received: 25 November 1999 / Revised version: 7 February 2000     

Vitamin A content (retinol and retinyl esters) in livers of different animals

In the present study, 90 animal livers of five different species (pig, cattle, calf, chicken, turkey) were examined for their vitamin A contents. The investigation of extracted vitamin A included all-trans retinol, retinyl palmitate, stearate, oleate and linoleate, expressed as retinol equivalents (RE). The separation of the various chemical forms was done using HPLC. The liver vitamin A contents ranged between 6.5 and 18.9 mg RE/100 g in pigs, from 1.1 to 6.7 mg RE/100 g in cattle and from 1.6 to 16.6 mg RE/100 g and 2.7 to 21.5 mg RE/100 g in chickens and turkeys, respectively. The livers of calves contained the smallest amount of vitamin A, with variation from 1.3 to 3.2 mg RE/100 g. Retinyl palmitate was the predominant form of vitamin A in the livers of investigated animals and contributed about 40% (avids) up to 75% (calf) of the total liver vitamin A contents. The results indicated that the lower levels of animal liver vitamin A, observed in our study, could be a result of small-structured agriculture in Austria. The variations of liver vitamin A concentrations among the species were a result of differences in race, age and the different feeding regimen.     

Provitamin A carotenoids and ascorbic acid contents of the different types of orange juices marketed in Spain

The vitamin C and provitamin A carotenoids contents of 25 commercially available Spanish orange juices were studied. Large differences in the levels of these compounds were found. On average, ultrafrozen orange juices (UFOJ) and orange juices from the ecological agriculture (OJFEA) showed the highest ascorbic acid contents (518 and 412 mg/l respectively) among the different kinds of orange juices studied. Some disagreement between the declared and the actual amounts of vitamin C were found. Provitamin A carotenoids were determined by means of the corresponding standards. The monohydroxycarotenoid accompanying β-cyptoxanthin in orange juices was identified as the non-provitamin A carotenoid, zeinoxanthin, on the basis of the methylation test with acidified methanol. Unusually high contents of β-carotene (>0.5 mg/l) were found in two samples, which could indicate that substantial amounts of the pigment were added to those juices. The mandarin juice analyzed showed the highest provitamin A activity (359.3 retinol activity equivalents/l) Among the orange juices surveyed, UFO proved to be the best source of provitamin A (78.5 retinol activity equivalents/l, on average). The lowest contents were found in orange juices from concentrate (OJFC) (22.4 retinol activity equivalents/l, on average, without considering the orange juices with unusual β-carotene contents).     

婴儿奶瓶及食品包装材料中双酚A的风险评估

双酚A作为婴儿奶瓶及食品包装材料的生产原料是否对人类的健康有潜在风险以及风险的大小如何,是公众和政府密切关注的问题.根据风险评估理论的四个步骤,即危害鉴定、危害特征描述、暴露评估和风险特征描述,对双酚A进行风险评估,结果表明人体暴露于双酚A的量是微不足道的,没有对人体健康构成已知的风险.     

Enzymatic determination of inulin in food and dietary supplements

 An enzymatic method for the determination of the oligofructoside inulin based on the enzymatic hydrolysis of inulin by inulinase was developed. Fructose formed in this reaction was phosphorylated by adenosine-5′-triphosphate and hexokinase, and isomerized to glucose-6-phosphate by phosphoglucose isomerase. Glucose-6-phosphate was finally oxidized to gluconate-6-phosphate by glucose-6-phosphate dehydrogenase. Reduced nicotinamide adenine dinucleotide phosphate formed in this sequence of reactions is determined spectrophotometrically by its absorbance at 340 nm. The absorbance is directly proportional to the initial amount of inulin. Precision, accuracy, repeatability and recovery rates of inulin following standard addition to sample solutions were evaluated. All steps of the enzymatic analysis were carried out on an automatic centrifugal analyzer. This, together with rapid and simple sample preparation, makes the method suitable for the routine determination of inulin in food surveilance and for quality control purposes. Received: 14 December 1998 / Revised version: 15 February 1999     

Determination of acrylamide content of food products in Korea

Acrylamide (AA) contents of commercial market‐purchased foods and of traditional home‐cooked Korean foods were investigated. The effect of cooking method on AA amount in potatoes was also studied. AA contents of roasted barley and corn ranged from 116 to 449 µg kg^?1 and of chips ranged from 12 to 3241 µg kg^?1, representing a very high variation in AA contents among tested samples. Lower levels of AA were found in wheat flour chips compared to potato chips. AA contents of ramen noodles were below 37 µg kg^?1, whether they contained potato starch or not. The AA contents of Korean home‐cooked oil fried foods increased in the following order: yakwa < whole deep‐fried sea tangle < ground and deep‐fried lotus root < ground and pan‐fried lotus root < French fries < ground and pan‐fried potato. Lotus root and garlic also had the potential to produce AA during cooking. Pre‐treatment such as grinding, boiling, freezing and thawing increased the AA formation in oil‐fried potato. Temperature was more influential than time on AA formation during deep‐oil frying. Removing water‐soluble fractions reduced AA content of cooked potatoes. Copyright © 2006 Society of Chemical Industry     

Content of trans fatty acids in margarines, plant oils, fried products and chocolate spreads in Austria

 On the Austrian market a selection of the available margarines, refined and cold pressed plant oils, chocolate spreads, snacks and fast food products were collected and the content of trans-fatty acids (TFA) was determined by a GLC procedure. The highest levels of TFA were observed in fast food products (mean, 5.9%, maximum, 21% of fatty acids), chocolate spreads (mean, 4.9%, maximum, 8.9% of fatty acids) and snacks (mean, 2.9%, maximum, 16% of fatty acids). Margarines with a "<1% TFA" declaration contained low amounts (0.3–0.8%), while the content of margarines with no such declaration was much higher (3.0–3.7%). A 7 h oxidation of plant oils at 120  °C demonstrated that the higher levels of TFA in heated oils are not associated with oxidation processes at this temperature. Based on the analysed data, the mean TFA intake (currently <4 g/day) has decreased due to a change in manufacturing conditions and the choice of unhydrogenated plant oils. In spite of this a diet high in snacks, fast food products or chocolate spreads, all products which are popular amongs children and adolescents, may increase the TFA intake up to >10 g/day. Received: 23 April 1999 / Revised version: 11 June 1999     

Determination of radiation-induced hydrocarbons in processed food and complex lipid matrices A new solid phase extraction (SPE) method for detection of irradiated components in food

 Detection of irradiated components in processed food with complex lipid matrices can be affected by two problems. First, the processed food may contain only a small amount of the irradiated component, and the radiation-induced hydrocarbons may be diluted throughout the lipid matrix of the whole food. Second, in complex lipid matrices, the detection of prior irradiation is often disturbed by fat-associated compounds. In these cases, common solid phase extraction (SPE) Florisil clean-up alone is inadequate in the detection of prior irradiation. Subsequent SPE argentation chromatography of the Florisil eluate allows the measurement of small amounts of irradiated lipid-containing ingredients in processed food as well as the detection of prior irradiation in complex lipid matrices such as paprika and chilli. SPE argentation chromatography is the first method available for the selective enrichment of radiation-specific hydrocarbons from even complex lipid matrices, thus enabling the detection of irradiation doses as low as 0.025 kGy. Furthermore, by using radiation-induced hydrocarbons in the detection of prior irradiation of paprika and chilli powder, a second independent method, the first being measurement of thermoluminescence, is available for the analysis of these matrices. Such analysis could be achieved by using this highly sensitive, cheap and easy to perform combined SPE Florisil/argentation chromatography method, without the need for sophisticated techniques like SFE-GC/MS or LC-GC/MS, so that highly sensitive detection of prior irradiation could be performed in almost every laboratory. Received: 19 February 1996/Revised version: 24 May 1996     

Can the water content of dairy products be determined accurately by microwave drying?

 Oven drying is the most frequently used moisture determination method. To obtain results faster than heating by convection in classic drying ovens, more rapid heating techniques are used. One of these is drying by microwaves. The result of all drying methods is mass loss under the conditions applied. Only in a few cases does the mass lost correspond exactly to the water content. Mass loss is caused by the evaporation of all volatile matter during the drying process, i.e. not only by the loss of water. Foodstuffs in particular risk decomposition reactions and the formation of volatile substances at higher temperatures. The results of drying processes depend on the drying parameters and are variable, whereas the water content is a specific property of the sample. If the water content is to be determined accurately by a drying process, the drying parameters must be adjusted in a way that the results equal those obtained by a specific method, e.g. the Karl Fischer titration. The dependence on the drying parameters varies for different products. In many cases the levels of a set of parameters can be determined so that the mass lost equals the analysed water content; in other situations a differing but reproducible result can be multiplied by a constant factor to give the reference value. This study shows that, for some dairy products, the water contents found by microwave drying are very close to those determined by Karl Fischer titration. Received: 26 May 1998     

Can the water content of dairy products be determined accurately by microwave drying?

 Oven drying is the most frequently used moisture determination method. To obtain results faster than heating by convection in classic drying ovens, more rapid heating techniques are used. One of these is drying by microwaves. The result of all drying methods is mass loss under the conditions applied. Only in a few cases does the mass lost correspond exactly to the water content. Mass loss is caused by the evaporation of all volatile matter during the drying process, i.e. not only by the loss of water. Foodstuffs in particular risk decomposition reactions and the formation of volatile substances at higher temperatures. The results of drying processes depend on the drying parameters and are variable, whereas the water content is a specific property of the sample. If the water content is to be determined accurately by a drying process, the drying parameters must be adjusted in a way that the results equal those obtained by a specific method, e.g. the Karl Fischer titration. The dependence on the drying parameters varies for different products. In many cases the levels of a set of parameters can be determined so that the mass lost equals the analysed water content; in other situations a differing but reproducible result can be multiplied by a constant factor to give the reference value. This study shows that, for some dairy products, the water contents found by microwave drying are very close to those determined by Karl Fischer titration. Received: 26 May 1998     

Nonenzymatic browning reactions of retro-aldol degradation products of carbohydrates

 Methylglyoxal and glyceraldehyde were used to demonstrate the involvement of retro-aldol degradation products of carbohydrates in browning (A ₄₂₀), the formation of hydroxymethylfurfural (HMF), and the extent to which the mechanism of browning proceeds by homolytic or heterolytic pathways in the caramelization and Maillard reactions of mono- and disaccharides. The amino component of Maillard systems is required for the retro-aldol cleavage of D-glucose. The short-chain α-dicarbonyl compounds so formed appear to dominate not only the formation of brown products but also the mechanism of the browning of D-glucose under these conditions, even if only small amounts are formed. Evidence is presented to link the formation of free radicals in the browning of glucose to reactions of the retro-aldol products. A novel reaction pathway is suggested for the formation of HMF from glyceraldehyde. Received: 9 October 1998 / Revised version: 15 December 1998