Effect of ultrasound treatments of tomato pulp on microstructure and lycopene in vitro bioaccessibility

The influence of ultrasound treatments of tomato pulp on microstructure and lycopene in vitro bioaccessibility was investigated. To this purpose, samples were subjected to ultrasound at a frequency and amplitude of 24 kHz and 100 μm, respectively, for increasing lengths of time. Results showed that ultrasound was responsible for loss of tomato cell integrity, as well as a decrease in the degree of pectin esterification. In contrast, rheological measurements showed that ultrasonically treated tomato pulp had greater gel-like properties than an untreated sample. It was inferred that ultrasound promoted the formation of a new network due to hydrogen bonding and hydrophobic interactions among the de-esterified pectin molecules. Such a reinforcement of the tomato pulp structure resulted in a decrease in lycopene in vitro bioaccessibility of the ultrasonically treated tomato pulp, probably due to the fact that the presence of a stronger network may make lycopene less available to the digestion process.     

Impact of Thermal and Pressure-Based Technologies on Carotenoid Retention and Quality Attributes in Tomato Juice

The aim of this study was to investigate the impact of thermal processing (TP) (90 °C, 90 s), high-pressure processing (HPP) (600 MPa, 46 °C, 5 min), and high-pressure homogenization (HPH) (246 MPa, 99 °C, <1 s) on product quality parameters, specifically carotenoid content, and physicochemical attributes of particle size, color, viscosity, total soluble solids, and pH in tomato juice. Unprocessed tomato juice was used as control. The four major species of carotenoids (lycopene, β-carotene, phytoene, and phytofluene) in tomato juice were analyzed by HPLC. The content of total lycopene, all-trans-lycopene, cis-lycopene isomers,  phytoene, and phytofluene, in TP-, HPP-, and HPH-treated tomato juice did not significantly differ from that in unprocessed (control) juice. Significant reduction in β-carotene content was observed after TP treatment but not after HPP and HPH treatments. HPH significantly reduced tomato juice particle volume mean diameter from ～330 μm in control, HPP-, and TP-treated tomato juices to ～17 μm. A concomitant increase in apparent viscosity was observed in HPH-treated juice versus control. HPH-treated juice had increased redness (a*) and yellowness (b*) than that in control and HPP-treated tomato juices. These results indicate that high-pressure-based technologies (HPP and HPH) can preserve carotenoids as well as improve physicochemical properties.     

Influence of chromoplast morphology on carotenoid bioaccessibility of carrot,mango, papaya,and tomato

Based on the observation of outstanding dissimilarities of the morphology of pigment-containing chromoplasts in nutritionally important carotenoid sources, the bioaccessibility (BA) of carotenoids from edible portions of carrot, mango, papaya, and tomato was compared using an in vitro digestion model. While carrot and tomato contained large carotenoid crystals clearly visible by light microscopy, mango and papaya contained different types of carotenoid-bearing structures. Particularly, β-carotene is deposited in globular and tubular elements in papaya and mango chromoplasts, where carotenoids accumulate in a lipid-dissolved and liquid-crystalline form, respectively. The highest BA of β-carotene was found for mango (10.1%), followed by papaya (5.3%), tomato (3.1%), and carrot (0.5%). In our digestion model, differences between total lycopene BA from papaya and tomato were insignificant, possibly since both pigments occur in a solid crystalline deposition form in both fruits. Furthermore, the BA of lutein, β-cryptoxanthin, and β-cryptoxanthin esters was shown to be superior to that of the carotenes from the respective food sources. The effect of lipid addition to the different food sources was studied. Although BA was enhanced for most carotenoids, the above-mentioned ranking of BAs of β-carotene remained unchanged after lipid addition. Consequently, the physical form of carotenoid deposition in plant chromoplasts is suggested to have major impact on their liberation efficiency from the food matrices.     

High pressure homogenization increases the in vitro bioaccessibility of α- and β-carotene in carrot emulsions but not of lycopene in tomato emulsions

Abstract: 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.     

Comparative fruit colouration in watermelon and tomato

The characteristic red pigmentation of watermelon and tomato fruits is determined by accumulation of the carotenoid pigment lycopene and this phenotype is polyphyletic. Since several carotenoids are known to have health promoting activity, and watermelon can be a significant source of lycopene and other carotenoids, it is important to understand the genetic basis of watermelon fruit-specific carotenoid biosynthesis. Unlike tomato, very little is known about the regulation of carotenoid biosynthesis during fruit development in watermelon, a non-climacteric fruit. We have HPLC analyzed the carotenoids of red, yellow and orange watermelons and compared their carotenoid patterns with those of known fruit colour mutants of tomato. Interestingly, we could detect tomato mutant equivalents to most watermelon fruit colour phenotypes, including r, og, B and t.     

Enhancing lycopene stability and bioaccessibility in homogenized tomato pulp using emulsion design principles

The objective of this study was to examine the impact of oil, emulsifier, and texture modifier addition on the bioaccessibility of lycopene in homogenized tomato pulp. Different types (olive or corn oil) and levels (0 to 8 wt%) of digestible lipids, a protein-based emulsifier (whey protein isolate, WPI) and/or a polysaccharide-based texture modifier (sodium alginate, SA) were added to the tomato pulp. The addition of these substances increased the amount of lycopene liberated from the tomato tissues. WPI addition led to the formation of smaller oil droplets during homogenization that scattered light more strongly, thereby leading to a tomato pulp that appeared more turbid. SA addition increased the viscosity of the tomato pulp, thereby increasing its uniformity. The best storage stability of lycopene in the tomato pulp was achieved by adding 8% corn oil and 1% WPI. However, the best in vitro bioaccessibility of lycopene (61.5%) was achieved using 6% olive oil and 1% SA. Overall, our results show that lycopene bioaccessibility in tomato products can be increased by careful manipulation of emulsion properties.Industrial relevance: Lycopene is a strongly hydrophobic carotenoid found in tomatoes that contributes to their desirable appearance and potential health benefits. However, it has poor chemical stability and low oral bioavailability, which limits its beneficial effects. We show that the stability and bioaccessibility of lycopene can be improved by high-pressure homogenization of tomato pulp in the presence of specific food additives. This approach may be suitable for the large-scale production of tomato products with enhanced health benefits.     

Effect of high pressure processing on gastrointestinal fate of carotenoids in mango juice: Insights obtained from macroscopic to microscopic scales

High hydrostatic pressure (HHP) and high-pressure homogenization (HPH) were applied to mango juice to explore their effects on gastric retention rate (G-CRR), bioaccessibility (BAC) of total and individual carotenoids, and the corresponding mechanisms from macroscopic to microscopic scales. Compared to the control, both HHP and HPH at 50 MPa had no significant effect on BAC and G-CRR, whereas HPH at 100 MPa significantly increased BAC by 44.33% and G-CRR by 11.84%. Further HHP treatments (particularly at 400 MPa) on the 100 MPa-HPH-pretreated samples significantly increased BAC by 71.37% and G-CRR by 24.24%. Violaxanthins/esters were less stable than carotenes in the stomach, resulting in lower bioaccessibility of violaxanthins/esters. G-CRR and BAC were negatively correlated with the viscosity and particle size of juice, whereas they were positively correlated with the solubility/dispersibility of carotenoids. In addition, pectin-carotenoid interactions may also be an important factor affecting the digestive fate of carotenoids in juice.Industrial relevanceHigh pressure processing (High hydrostatic pressure, HHP, and high pressure homogenization, HPH) is a non-thermal technique and its effect on the bioaccessibility of carotenoids in fruits and vegetables have attracted attention from researchers. Our research found that HPH and HHP combined treatment could decrease the particle size of mango juice, and increase the viscosity and turbidity as well as the bioaccessibility of carotenoids therein. This technology can be used to preserve the physical stability of mango juice and improve the nutritional value.     

The type and quantity of lipids present during digestion influence the in vitro bioaccessibility of lycopene from raw tomato pulp

This study elucidates the impact of the type and quantity of lipids, added upon digestion of raw tomato pulp, on the bioaccessibility of lycopene. Lycopene bioaccessibility was studied by measuring the micellarization during in vitro digestion. Coconut oil, palm oil, cocoa butter, olive oil, sunflower oil and fish oil were selected because of their distinctly different fatty acid composition. Upon adding 5% of lipid to raw tomato pulp, all tested lipids significantly improved the lycopene bioaccessibility. The largest increase in lycopene bioaccessibility was noticed after supplying 5% of sunflower oil, followed by olive oil and cocoa butter (not all differences were significant). A slightly smaller increase was observed when fish oil, coconut oil and palm oil were used. In addition, the effect of different quantities (0–10%) of coconut oil, olive oil and fish oil was examined. Over the entire concentration range, increasing the amount of coconut oil increased the lycopene bioaccessibility, while the highest bioaccessibility was found using 1 and 2% of respectively fish oil and olive oil. Moreover, depending on the amount of added lipid, the type of lipid resulting in the highest lycopene bioaccessibility differed. The results obtained clearly indicate that lycopene bioaccessibility depends both on the type and on the quantity of the lipid present during in vitro digestion of raw tomato pulp.     

Mastication effects on carotenoid bioaccessibility from mango fruit tissue

The release of carotenoids from fresh fruits or vegetables is determined by the encapsulating plant tissue matrix, intracellular carotenoid location within the cell, and the mastication process. The objectives of this study were to assess the particle sizes obtained after mastication of mango fruit tissue, and how the resulting degree of plant tissue rupture affects carotenoid bioaccessibility. A fine and a coarse chewer were selected after screening 20 healthy volunteers for in vivo human mastication, and the collected chewed boluses were subjected to wet sieving fractionation, followed by an in vitro gastric and small intestinal digestion model. Confocal micrographs show that the smallest particle size fraction (0.075 mm) consists mostly of fragmented cells and the largest size fraction (2.8 mm) contains bulky clusters of whole cells and vascular fibers. Higher amounts of total carotenoids (211–320 μg/100 g) were observed in the larger particle size fraction (2.8 mm) relative to the 1 mm (192–249 μg/100 g) and 0.075 mm fractions (136–199 μg/100 g). Smaller particles showed a greater % release of total carotenoids after in vitro digestion. Xanthophyll derivatives are more bioaccessible than β-carotene for all particle sizes. The effects of particle size or degree of fine vs coarse chewing are unexpectedly small (p > 0.05), but the process of chewing substantially reduced the release of β-carotene and xanthophylls by 34% and 18%, respectively. While there is a (small) particle size effect, this appears to not be the primary factor controlling bioaccessibility for soft tissues such as mango, in contrast to previous reports that a single cell wall appears to be enough to prevent bioaccessibility of carotenoids in more robust carrot tissues.     

In vitro bioaccessibility of carotenoids and tocopherols from fruits and vegetables

Aim of the study

To assess the in vitro bioaccessibility of carotenoids, including xanthophyll esters, and tocopherols from fruits and vegetables.

Results

Stability for carotenoids and tocopherols was over 70%. Xanthophyll esters were cleaved by cholesterol esterase but not by human pancreatic lipase. Less than 40% of the β-cryptoxanthin initially present was hydrolyzed and the amount of free xanthophylls recovered was higher when liquid was used than when fresh homogenized matrix was employed. cis-Isomers of β-carotene and lutein did not significantly increase during the process. Xanthophylls were more efficiently transferred into supernatants than tocopherols and β-carotene. cis-Carotenoids, epoxy-xanthophylls and ester forms were also transferred.

Conclusion

The results are consistent with observations in other in vitro digestion models and human studies and support the usefulness of in vitro assessment to study food-related determinants of the bioavailability of carotenoids and tocopherols from fruits and vegetables.     

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 β‐carotene as well as textural properties. Thermal treatments used were low (60 °C) and high (90 °C) temperature blanching followed by boiling. RESULTS: Lycopene was relatively stable during thermal treatment, whereas β‐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. Copyright © 2010 Society of Chemical Industry     

Physicochemical parameters that influence carotenoids bioaccessibility from a tomato juice

In vitro digestion models have been developed to estimate carotenoid bioavailability but most do not consider that their diffusion from fruit matrix to the lipid phase of the bolus could be a limiting step. Therefore we designed a model in which tomato juice is mixed with oil or oil/water emulsions, and the carotenoids diffusing to oil are measured by spectrometry. Temperature, pH and tomato juice/peanut oil ratio were evaluated for their influence on carotenoid diffusion. When oil/tomato ratio was between 0.11 and 1, extraction of lycopene was limited by the saturation of the oil phase. With a large excess of oil, diffusion was also limited, as only 31 ± 1% of lycopene could be extracted from the juice. Diffusion did not vary significantly with pH but doubled when temperature rose from 10 °C to 37 °C.     

Lutein-enriched frankfurter-type products: Physicochemical characteristics and lutein in vitro bioaccessibility

This paper reports a study of the physicochemical characteristics of lutein-enriched frankfurter-type products with two fat levels, and the lutein in vitro bioaccessibility in these products. In general, the high-fat products possessed better emulsion stability and greater hardness and chewiness than low-fat samples. For each fat level, the addition of lutein extract in olive oil reduced emulsion stability in meat products. The presence of lutein reduced the lightness and increased the redness of samples. Lutein was highly stable upon in vitro digestion, with overall recovery of over 84% at the end of the duodenal phase and very low isomerisation. Micellarisation was high but depended on the fat content, ranging from 29–34% (for the low-fat sample) up to 73–81% of the amount initially present (for the high-fat sample). Storage (22 days at 4 °C) did not significantly affect lutein content or bioaccessibility. Our results support the suitability of meat products as lutein carriers and as a means to increase the systematic intake of lutein.     

In vitro bioaccesibility of lutein and zeaxanthin from the microalgae Scenedesmus almeriensis

Aim of the study

To assess the in vitro bioaccessibility of lutein and zeaxanthin from lyophilised biomass and lutein-enriched extracts in olive oil produced from a lutein overproducing strain of Scenedesmus almeriensis.

Results

Lutein and zeaxanhin were mostly present in free form (>90–95%). Both xanthophylls were highly stable upon in vitro digestion, with an overall recovery above 75% (lyophilised biomass) and very low isomerization, whilst micellarization was <1% of the amount initially present and cis-isomers of lutein and β-carotene were preferentially incorporated. Using lutein-enriched extracts in olive oil, the micellarization of lutein and zeaxanthin increased dramatically reaching values up to 80–90% of the amounts initially present.

Conclusion

The lyophilised biomass of S. almeriensis constitutes a very rich source of free lutein (and zeaxanthin) but poorly bioaccesible. However, oil extracts from this lyophilised biomass are highly bioaccesible and may supply amounts of lutein and zeaxanthin comparable to or higher than those provided by traditional foods.     

Antioxidant activity of tomato lipophilic extracts and interactions between carotenoids and α-tocopherol in synthetic mixtures

In the present study we assayed the antioxidant activity of lipophilic extracts obtained from different tomato varieties. The results showed that cherry tomatoes, characterized by a high carotenoid content, had the highest antioxidant activity. A quantitative analysis of lycopene, β-carotene, lutein and α-tocopherol was also performed and the correlation between the antioxidant content and the antioxidant activity was estimated. The highest correlation coefficient was found for lycopene (R² = 0.9236, P ≤ 0.001). The analysis of two-component mixtures containing α-tocopherol and carotenoids showed that significant synergism occurred for all the combinations which contained α-tocopherol and β-carotene mixed together. The highest synergistic effects were detected for α-tocopherol-lycopene mixtures, which were the most efficient combinations tested in the present study. The analysis of the carotenoid combinations indicated that synergism occurred for lycopene-β-carotene, lycopene-lutein and lutein-β-carotene mixtures. The analysis of four-component mixtures did not show statistically significant synergistic effects.     

CD36 is involved in lycopene and lutein uptake by adipocytes and adipose tissue cultures

Scope: Carotenoids are mainly stored in adipose tissue. However, nothing is known regarding the uptake of carotenoids by adipocytes. Thus, our study explored the mechanism by which lycopene and lutein, two major human plasma carotenoids, are transported. Methods and results: CD36 was a putative candidate for this uptake, 3T3‐L1 cells were treated with sulfosuccinimidyl oleate, a CD36‐specific inhibitor. sulfosuccinimidyl oleate‐treated cells showed a significant decrease in both lycopene and lutein uptake as compared to control cells. Their uptake was also decreased by partial inhibition of CD36 expression using siRNA, whereas the overexpression of CD36 in Cos‐1 cells increased their uptake. Finally, the effect of CD36 on carotenoid uptake was confirmed ex vivo in cultures of adipose tissue explants from CD36^?/? mice, which exhibited reduced carotenoid uptake as compared to wild‐type mice explants. Conclusion: For the first time, we report the involvement of a transporter, CD36, in carotenoid uptake by adipocytes and adipose tissue.     

The effect of domestic processing on the content and bioaccessibility of carotenoids from chili peppers (Capsicum species)

The content and bioaccessibility of carotenoids from different chili peppers were analysed and the effects of typical domestic processing were investigated. Peppers were analysed before and after cooking by conventional boiling (10 min in 100 °C water) and also following a freezing period of four months in a domestic freezer (−20 °C). The content and bioaccessibility of the eight carotenoids quantified varied, depending on cultivar, species, colour and processing. Provitamin A carotenoids (β-carotene and β-cryptoxanthin) and capsanthin were present at highest concentrations in the samples before and after processing. In general, yellow and orange peppers were the best sources of lutein, zeaxanthin and neoxanthin. Xanthophyll carotenoids were more efficiently transferred to the micelles and, therefore, were also more bioavailable. Processing decreased the carotenoid content in certain samples; however, the micellar content was generally not lower for processed peppers; therefore the bioaccessibility of carotenoids from processed peppers is enhanced relative to unprocessed peppers.     

Determination of Carotenoids in Fruits of Rosa sp. (Rosa Canina and Rosa Rugosa) and of Chokeberry (Aronia Melanocarpa)

Carotenoid composition of fruits of two Rosa species (Rosa canina and Rosa rugosa) and of chokeberry (Aronia melanocarpa) was studied by high performance liquid chromatography. Nine carotenoids were determined: three carotenes (lycopene, ζ-carotene, β-carotene) and six xanthophylls (neoxanthin, trans-violaxanthin, cis-violaxan-thin, 5,6-epoxylutein, lutein, β-cryptoxanthin). This high number of compounds classified these fruits among those with the greatest variety of carotenoid pigments. Quantitatively large differences occurred in the carotenoid composition of the three fruits. Rosa hips contained the highest concentrations of total carotenoids, which were mainly comprised of lycopene and βcarotene. Conversely, total xanthophylls were low. In contrast to Rosa, fruits of Aronia were lower in total carotenoids while xanthophylls composed a higher proportion.     

Carotenoid transfer to oil during thermal processing of low fat carrot and tomato particle based suspensions

Carotenoid solubilization in the oil phase is a prerequisite for carotenoid bioaccessibility during digestion. However, the level of bioencapsulation and the hydrophobicity of carotenoids were proven to strongly affect their transfer to oil during in vitro digestion. Therefore, thermal processing (95–110 °C) was exploited to favor carotenoid transfer from tomato- and carrot-based fractions to the oil before digestion. Initially, the total (all-trans + cis) carotenoid content in the oil increased quickly, thereafter, depending on the temperature applied, either a drop or a plateau was reached at longer treatment times. Treatment conditions of > 100 °C for 10 min significantly favoured carotenoid transfer to oil (≥ 75%). The rates of transfer to oil were as follows: β-carotene ≈ α-carotene > lycopene. The results revealed that the cell wall hinders carotenoid transfer to oil during thermal processing. Overall, the results indicate that typical high temperature short time thermal processing can be sufficient to achieve maximal carotenoid transfer to oil with minimal degradation in real food systems/food emulsions and this can be crucial to improve the nutritional quality of carrot and tomato based products.     

Properties of starch nanoparticle obtained by ultrasonication and high pressure homogenization for developing carotenoids-enriched powder and Pickering nanoemulsion

The effect of ultrasound (US) and high pressure homogenization (HPH) on starch nanoparticles and their ability to stabilize Pickering nanoemulsion of carotenoids and bioactives-enriched olive oil was evaluated. The carotenoids used in nanoemulsion were extracted from the peel of passion fruit (Passiflora edulis). As the US treatment time increased, mean particle size decreased from microsize to 340 nm and subsequent HPH treatment of this suspension caused further decrease in particles size (<60 nm). US and HPH treatments increased swelling and solubility and also the gelatinization and melting temperatures of the starch nanoparticles. The Pickering nanoemulsion was rich in carotenoids and total phenolic content and exhibited high antioxidant activity, which had protective effect on its stability. The carotenoids-enriched nanoemulsion was found to be stable to heat and freeze-thaw treatments. The developed nanoemulsion showed better oxidative stability as well as physical stability during storage at 6 °C and 25 °C.