Cecilia Svelander

Processing of tomato: impact on in vitro bioaccessibility of lycopene and textural properties

BACKGROUND Human studies have demonstrated that processing of tomato can greatly increase lycopene bioavailability. However, the difference between processing methods is not widely investigated. In the current study different thermal treatments of tomato were evaluated with regard to their impact on in vitro bioaccessibility and retention of lycopene and beta-carotene as well as textural properties. Thermal treatments used were low (60 degrees C) and high (90 degrees C) temperature blanching followed by boiling. RESULTS Lycopene was relatively stable during thermal treatment, whereas beta-carotene was significantly (P < 0.05) reduced by all heat treatments except for low temperature blanching. In vitro bioaccessibility of lycopene was significantly increased from 5.1 +/- 0.2 to 9.2 +/- 1.8 and 9.7 +/- 0.6 mg kg(-1) for low and high temperature blanching, respectively. An additional boiling step after blanching did not further improve lycopene bioaccessibility for any treatment, but significantly reduced the consistency of low temperature treated samples. CONCLUSION Choice and order of processing treatments can have a large impact on both lycopene bioavailability and texture of tomato products. Further investigations are needed, but this study provides one of the first steps towards tomato products tailored to optimise nutritional benefits.

High Pressure Homogenization Increases the In Vitro Bioaccessibility of α- and β-Carotene in Carrot Emulsions But Not of Lycopene in Tomato Emulsions

UNLABELLED The correlation between food microstructure and in vitro bioaccessibility of carotenes was evaluated for tomato and carrot emulsions (5% olive oil) subjected to high pressure homogenization (HPH) at varying degrees of intensity. The aim was to investigate whether additional mechanical disruption of the food matrix could be utilized to further increase the carotene bioaccessibility of an already pre-processed material. The carotene bioaccessibility of the samples was measured after simulated in vitro digestion, carotene release to the oil phase was estimated by Confocal Raman spectroscopy and, to measure active uptake of carotenes, Caco-2 cells were incubated with the digesta of selected samples. HPH did not notably affect the retention of carotenes or ascorbic acid but significantly increased both the release and micellar incorporation of α- and β-carotene in carrot emulsions 1.5- to 1.6-fold. On the other hand, in vitro bioaccessibility of lycopene from tomato was not increased by HPH under any of the conditions investigated. Instead, the results suggested that lycopene bioaccessibility was limited by a combination of the low solubility of lycopene in dietary lipids and entrapment in the cellular network. Carotene uptake by Caco-2 cells appeared to be mainly dependent upon the carotene concentration of the digesta, but cis-trans isomerization had a significant impact on the micellarization efficiency of carotenes. We therefore conclude that HPH is an interesting option for increasing the bioaccessibility of carotenes from fruits and vegetables while maintaining a high nutrient content, but that the results will depend on both food source and type of carotene. PRACTICAL APPLICATION A better understanding of the correlation between the processing of fruits and vegetables, microstructure and nutrient bioaccessibility can be directly applied in the production of food products with an increased nutritional value.

Mechanical and thermal pretreatments of crushed tomatoes: Effects on consistency and in vitro accessibility of lycopene

The effects of mechanical and thermal treatments on the consistency and in vitro lycopene accessibility of crushed tomatoes were evaluated. Different crushing intensities and a subsequent heat treatment carried out as a heat shock (95 degrees C for 8 min) or a boiling step (100 degrees C for 20 min) were examined. Additional homogenization was compared with milder crushing regarding the effect on lycopene content and in vitro accessibility. Textural properties, polygalacturonase and pectinmethylesterase activity, pectin degree of methoxylation, lycopene content, and in vitro lycopene accessibility were evaluated. Microstructure was studied using both light and transmission electron microscopy. Crushing and subsequent heating affected the pectin degree of methoxylation and the consistency of the crushed tomatoes. The mechanical and thermal treatments did not affect the lycopene content to any great extent; however, in vitro accessibility seemed to improve with extensive crushing followed by heating. Crushing or homogenization in itself was not enough to increase in vitro lycopene accessibility.

Herring and Beef Meals Lead to Differences in Plasma 2-Aminoadipic Acid, β-Alanine, 4-Hydroxyproline, Cetoleic Acid, and Docosahexaenoic Acid Concentrations in Overweight Men

BACKGROUND Dietary guidelines generally recommend increasing fish intake and reducing red meat intake for better long-term health. Few studies have compared the metabolic differences between eating meat and fish. OBJECTIVE The objective of this study was to determine whether there are differences in the postprandial plasma metabolic response to meals containing baked beef, baked herring, and pickled herring. METHODS Seventeen overweight men (BMI 25-30 kg/m(2), 41-67 y of age) were included in a randomized crossover intervention study. Subjects ate baked herring-, pickled herring-, and baked beef-based meals in a randomized order and postprandial blood plasma samples were taken over 7 h. Plasma metabolomics were measured with the use of gas chromatography-mass spectrometry and areas under the curve for detected metabolites were compared between meals. RESULTS The plasma postprandial response of 2-aminoadipic acid, a suggested marker of diabetes risk, was 1.6 times higher after the beef meal than after the baked herring meal (P < 0.001). Plasma β-alanine and 4-hydroxyproline both were markedly greater after beef intake than after herring intake (16 and 3.4 times the response of baked herring, respectively; P < 0.001). Herring intake led to a greater plasma postprandial response from docosahexaenoic acid (DHA) and cetoleic acid compared with beef (17.6 and 150 times greater, respectively; P < 0.001), whereas hippuric acid and benzoic acid were elevated after pickled herring compared with baked herring (5.4 and 43 times higher; P < 0.001). CONCLUSIONS These results in overweight men confirm that DHA and cetoleic acid reflect herring intake, whereas β-alanine and 4-hydroxyproline are potential biomarkers for beef intake. The greater postprandial rise in 2-aminoadipic acid after the beef meal, coupled to its proposed role in stimulating insulin secretion, may have importance in the context of red meat intake and increased diabetes risk. This trial was registered at clinicaltrials.gov as NCT02381613.

Identification and quantification of even and odd chained 5-n alkylresorcinols, branched chain-alkylresorcinols and methylalkylresorcinols in Quinoa (Chenopodium quinoa)

Quinoa is a pseudocereal grown in the Andean region of South America that is of increasing interest worldwide as an alternative staple food. We have detected a complex mixture of both odd- and even-alkyl chain alkylresorcinols (AR), branched-chain alkylresorcinols (bcAR) and methylalkylresorcinols (mAR) in ethyl acetate extracts of quinoa. We quantified the content of AR in 17 commercial samples of quinoa, and found that the mean±SD content of AR was 58±16μg/g, bcAR was 182±52μg/g, and mAR was 136±40μg/g. AR from quinoa could also be detected in plasma after eating quinoa, indicating that some of these unique AR could be used as biomarkers of quinoa intake in humans. Further work is required to understand the role of these ARs in the quinoa plant and whether any of the novel ARs may be of particular interest in human nutrition.

A high-throughput method for liquid chromatography–tandem mass spectrometry determination of plasma alkylresorcinols, biomarkers of whole grain wheat and rye intake

Plasma alkylresorcinols are increasingly analyzed in cohort studies to improve estimates of whole grain intake and their relationship with disease incidence. Current methods require large volumes of solvent (>10 ml/sample) and have relatively low daily sample throughput. We tested five different supported extraction methods for extracting alkylresorcinols from plasma and improved a normal-phase liquid chromatography coupled to a tandem mass spectrometer method to reduce sample analysis time. The method was validated and compared with gas chromatography-mass spectrometry analysis. Sample preparation with HybridSPE supported extraction was most effective for alkylresorcinol extraction, with recoveries of 77-82% from 100 μl of plasma. The use of 96-well plates allowed extraction of 160 samples per day. Using a 5-cm NH2 column and heptane reduced run times to 3 min. The new method had a limit of detection and limit of quantification equivalent to 1.1-1.8 nmol/L and 3.5-6.1 nmol/L plasma, respectively, for the different alkylresorcinol homologues. Accuracy was 93-105%, and intra- and inter-batch precision values were 4-18% across different plasma concentrations. This method makes it possible to quantify plasma alkylresorcinols in 100 μl of plasma at a rate of at least 160 samples per day without the need for large volumes of organic solvents.

Supercritical Fluid Extraction of Berry Seeds: Chemical Composition and Antioxidant Activity

The influence of supercritical fluid extraction (SFE) and solvent extraction of oils from cloudberry, bilberry, and black currant seeds on the yield, chemical properties, and recovery of antioxidant compounds was investigated. SFE was performed for 1 h at 350 bar and at 50°C and 80°C. Fatty acids, vitamin E, carotenoids, and free radical-scavenging activity (DPPH) were assayed. SFE at 80°C resulted in higher oil yields for cloudberry and black currant seeds. The oils were rich in polyunsaturated fatty acids (PUFAs) (66.8%–75.9% w/w), with high percentages of linoleic and α-linolenic acids. The black currant seed extracts had the highest concentrations of vitamin E (range, 113.0–241.8 mg/100 g oil) and carotenoids (range, 11.5–32.3 mg/100 g oil) and the highest antioxidant activity. The cloudberry seed oils also had high antioxidant content and activity. These findings indicate the potential of SFE for the recovery of PUFA and antioxidant compounds in berry by-products.