Esterification enhances carotenoid retention during bread-making.

Free and esterified forms of sterols provide detailed information on the identity and the quality of vegetable oils. In this study, 4,4′‐dimethylsterols in free and esterified forms were investigated in hazelnut and virgin olive oils. Moreover, a sample of solvent‐extracted hazelnut oil was refined at the laboratory to monitor the effects of processing on the levels of 4,4′‐dimethylsterols. Generally, the level of total 4,4′‐dimethyslterols was higher in the esterified form (49–68%) compared with that in free form (32–51%) of these compounds in the hazelnut oil. In virgin olive oil samples, cycloartenol and 24‐methylenecycloartanol were present in higher amounts in free forms (70–80%) than in esterified forms (20–30%). Among the refining processes, degumming, deodorization, neutralization and bleaching, only neutralization and bleaching considerably reduced 4,4′‐dimethylsterols. In fully refined hazelnut oil, 18 and 37% of lupeol and an unknown compound X in the esterified form were lost, respectively. The loss of these two compounds in the free form was considerably higher, 26 and 72%, respectively. GC–MS analysis showed that adulteration of olive oil with a sample of fully refined hazelnut oil could be detected at a level as low as 2% by tracing lupeol in total or only in esterified forms of 4,4′‐dimethylsterols. Further studies on the levels of free and esterified 4,4′‐dimethylsterols and their retention during refining processes are anticipated in hazelnut cultivars from different origins.

Hazelnuts are characterized by a relatively high abundance of oleic acid and poly-unsaturated fatty acids, which give this fruit a high nutritional value. As a counterbalance, such a lipid profile is more susceptible to autoxidation and/or degradation reactions under enzymatic catalysis. Lipid oxidation occurs on fatty acids (FAs), both esterified on triacylglycerols and in free form (after lipolysis), but with favorable kinetics on the latter. In this study, the quali-quantitative changes in FA profiles (both free and esterified) were monitored during the shelf life (time 0, 6, and 12 months) as a function of different drying and storage conditions and different cultivars and geographical areas. A derivatization/extraction procedure was performed to quantify the profile of free and esterified fatty acids accurately. The overall profile of the free and esterified fatty acids concurred to create a biological signature characteristic of the cultivar and of the harvest region. The free and esterified forms’ characterization enabled the efficient monitoring of the effects of both the hydrolytic activity (increment in overall free fatty acids) and the oxidative process (decrease in unsaturated free fatty acids versus esterified fatty acids) over the 12 months of storage.

It has long been known that the plasma lipids do not constitute a uniform class of substances. Several fractions may be differentiated on the basis of their chemical structures, the most important of which are triglycerides, cholesterol (in free or esterified form), phospholipids, and free fatty acids. The plasma lipids do not occur in free form but are bound to and transported by proteins. While free fatty acids can bind to albumin, triglycerides, cholesterol (free or esterified), and phospholipids form larger complexes with so-called apoproteins; these are called lipoproteins. With the aid of electrophoresis and ultracentrifugation it is possible to differentiate four principle fractions of plasma lipoproteins. These differ from each other in particular by physicochemical properties relating to their electrophoretic rates of migration, optical density, sedimentation constants, and their contents of apoproteins as well as of triglycerides, cholesterol, and phospholipids.

The rp allele causes a significant reduction in total carotenoid pigmentation in carrot (Daucus carota L.) roots. The objective was to investigate the effect of rp on the composition, accumulation, and retention of carotenoids in two near-isolines of carrot, W266RPRP and W266rprp, during vegetative growth and postharvest storage. Field experiments were conducted during 1996 and 1997 in which roots were sampled weekly from 62 to 100 days after seed-sowing and biweekly during postharvest storage at 4 °C up to 386 days after sowing. Linear increases in total carotenoid concentration were observed for W266RPRP and W266rprp during vegetative growth. The average daily rate of increase in total carotenoid concentration in W266RPRP and in W266rprp was 12.7 and 1.3 mg·g-1 dry weight, respectively. A linear decrease in carotenoid concentration was measured for W266RPRP but not for W266rprp during postharvest storage. At 100 days after sowing, high-performance liquid chromatography analyses showed W266rprp had 20-fold lower concentrations of a-carotene and 50-fold lower concentrations of β-carotene in root tissue compared to W266RPRP. Levels of β-carotene and lutein in the first true leaves were reduced by ≈50% in W266rprp compared to W266RPRP. Results from this investigation suggest that the rp allele affects the concentration of root and foliage carotenoids, as well as the rate of carotenoid accumulation and degradation in carrot roots. The impact of the rp allele is far greater in root tissue than in foliage, suggesting it may act as a transcription factor or structural gene affecting primarily root carotenoid biosynthesis.

Apparent digestibility, deposition and retention of carotenoids in the muscle of rainbow trout, Oncorhynchus mykiss, were investigated comparing the feeding of pigments from Chlorella vulgaris against commercially available pigments at two different total lipid contents (15% and 20% lipid). Algal biomass (ALG) was included in rainbow trout diets and muscle pigmentation was compared to that obtained in trout fed diets containing a 5:3 mixture of canthaxanthin and astaxanthin (MIX) (reflecting the relative concentrations of these carotenoids in the dry alga) or those fed a diet containing astaxanthin only (AST). Apparent digestibilities of pigments and nutrients were determined by the indirect method, using Cr2 O3 as indicator, and the colour intensity and pigment concentration were assessed in the muscle, using the Roche colour card for salmonids and UV-vis spectrophotometry. After 6 weeks feeding, colour intensity was similar for the various pigment sources, achieving levels 12 to 13, yet significantly higher in fish fed the diet with the higher lipid content (≈ 20%) (p<0.05). Pigment concentration in the muscle was also higher in the fish fed the high-fat diet. Muscle pigment concentrations were similar for fish fed diets ALG and MIX, and over 1.5 times higher than for diet AST (p<0.05) after 6 weeks. Apparent digestibility of dry matter, crude protein, lipid, total energy and specific carotenoid concentrations were also measured. Increased dietary fat content was shown to increase the deposition and the retention of carotenoids in muscle, and the difference increased with time (deposition increase of 10–20% at week 3 and 30–40% at week 6 and retention increase of 10–15% at week 3 and 30% at week 6). Pigment digestibility also apparently increases (10–20%) under those conditions despite the fact that no significant effects in terms of apparent digestibility increase were found for dry matter, protein, lipids or energy. © Rapid Science Ltd. 1998

Free, esterified, and insoluble-bound phenolic acids in white and red Korean ginsengs ( Panax ginseng C.A. Meyer)

Targeting esterified oxylipins by LC–MS - Effect of sample preparation on oxylipin pattern

Effect of vacuum inclusion on the quality and the sensory attributes of carrot snacks

Diets containing 75ppm carotenoids were fed over a 15-week period to Arctic char (Salvelinus alpinus). Carotenoid content in flesh and skin was increased form 1.35 and 10.73 ug/g wet tissue to 5.56 and 41.21 ug/g, respectively. Subsequent feeding over a 7-week period on diets devoid of astaxanthin resulted in a decrease of 66.01 and 55.55% in carotehoid concentrations, Storage of the fillets for up to 12 days at 4°C air or at -20°C under vacuumpackaging conditions for 0 days had little effect on carotenoid retention with only 1.93-8.47% decrease. Crude protein content before feeding carotenoid-containing diets was 19.21% and this increase to 20.25 -21.05% after 15 weeks. The corresponding PER value of before and after feeding was 3.18-3.20 and essential amino acid index of samples varied between 126.45 and 128.77. The caloric values of the unpigmented and pigment4ed fillets were not significantly different. Eicosapentaenoic and docsahexaenoic acids were presented at 6.63-7.43% and 10.78-14.64% in fish fed pigmented diets, respectively and fillets contained between 54.66 and 60.49mg cholesterol/ 100g sample. The major minerals present were potassium and phosphorus, 239.03 and 256.01-274.05 mg% in pigmented fish, respectively. During peimentations, the level of calcium decreased form 18.81 to 6.00-8.80 mg% while the content of B vitamins increased form 3.04 to 5.86 mg%. Free amino acid content in all samples varied between 295.03 and 364.23 mg%. No histamine was detached in any of the products.

Incorporation of microencapsulated hydrophilic and lipophilic nutrients into foods by using ultrasound as a pre-treatment for drying: A prospective study

The present study aimed to evaluate the effects of long-term storage on the carotenoid pigments present in whole-grain flours prepared from durum wheat and tritordeum. As expected, higher storage temperatures showed a catabolic effect, which was very marked for free carotenoid pigments. Surprisingly, for both cereal genotypes, the thermal conditions favoured the synthesis of lutein esters, leading to an enhanced stability, slower degradation, and, subsequently, a greater carotenoid retention. The putative involvement of lipase enzymes in lutein esterification in flours is discussed, particularly regarding the preferential esterification of the hydroxyl group with linoleic acid at the 3′ in the ε-ring of the lutein molecule. The negative effects of processing on carotenoid retention were less pronounced in durum wheat flours, which could be due to an increased esterifying activity (the de novo formation of diesterified xanthophylls was observed). Moreover, clear differences were observed for tritordeum depending on whether the lutein was in a free or esterified state. For instance, lutein-3′-O-monolinoleate showed a three-fold lower degradation rate than free lutein at 37 °C. In view of our results, we advise that the biofortification research aimed at increasing the carotenoid contents in cereals should be based on the selection of varieties with an enhanced content of esterified xanthophylls.

Carotenogenesis and carotenoid esterification in biofilms of the microalga Coelastrella rubescens KGU-Y002 in the aerial phase

Copper nanoparticles were synthesized via a bioreduction using sulfated polysaccharides (SPs) extracted from Avicennia marina mangrove leaves and their phytotoxicity effect on wheat (Triticum aestivum L.) seedlings was assessed. As analyzed by high-performance liquid chromatography (HPLC), SPs extract constituted mainly 49.3% glucose, 24.6% galactose and 20.5% glucouronic acid by mol. A nanoformulation of ultrafine Cu2O/Cu(OH)2 nanoparticles coated with SPs (Cu NPs) was prepared with an average particle size of 2.11 ± 0.64 nm and a slightly negatively-charged zeta potential of 11 ± 0.46 mV. Applying high concentrations of Cu NPs on wheat seeds inhibited the respective shoot and root relative growth percentages, yielding 13.22 ± 9.91 and 36.72 ± 18.51% at 0.06 mg/mL of the nanoformulation. Comparable values were obtained when the seeds were subjected to 0.06 mg/L of SPs extract applied in the free form. In a foliar application, 0.06 mg/mL of Cu NPs reduced the respective total chlorophyll and carotenoids contents by 17.4% and 24.3% relative to the control while the treatment with SPs reduced them by slightly higher values of 27.9% and 32.6%, respectively, after 14 days of application. Therefore, Cu NPs show a comparable inhibition effect to that of the free SPs extract but offer the additional advantages of nanoformulations. In soil applications, however, Cu NPs stimulated the growth of wheat seedlings in contrary to SPs and increased the total chlorophyll and carotenoids by 49.76% and 70%, respectively. This gives an additional merit to the nanoformulation that can potentially be used as an effective biostimulant in soil.

Carotenoid pigments in two species of lobsters, Scyllarides squamosus (=Scyllarus sieboldi) (I) and Parribacus antarcticus (=p. ursus-major) (II), were analyzed and the results were compared with those of Panulirus japonicus (III) reported in a previous paper. The carapace of I, II and III were almost similar in carotenoid content, astaxanthin comprising nearly half of the total content with such carotenoids as β-carotene, echinenone, canthaxanthin, phoenicoxanthin, lutein and zeaxanthin being relatively minor. However, I and III which are taxonomically closely related species also contained 4-keto-zeaxanthin and cynthiaxanthin, which accounted for about 30% and 10% of the total carotenoid content respectively (4-keto-zeaxanthin=30%; cynthiaxanthin=10%), while II entirely lacked both pigments.In the eggs, the carotenoids were found only in the free form and their carotenoid patterns were similar to those in the carapace of the respective species examined. In I and III, the main carotenoid was astaxanthin which comprised about 40% of the total while in II, it was β-carotene (40%). β-carotene was the dominant carotenoid in the hepatopancreas of I, II and III, comprising 80 to 90% of the total. 4-Keto-zeaxanthin was identified in I and III in spite of the fact that its occurrence in crustacea has never been reported, possibly because its separation from astaxanthin during analysis is difficult.

Can a high chlorophyllase activity bias the use of the phytyldiol versus phytol ratio (CPPI) for the monitoring of chlorophyll photooxidation in seawater?