The impact of industrial processing on health-beneficial tomato microconstituents

The effect of industrial processing was investigated on the stability of tomato carotenoids, phenolic compounds and ascorbic acid. A deep insight in the processed products allowed the quantification of caffeic acid hexosides, which are far more important contributors than the well-known chlorogenic acid, dicaffeoylquinic acids and quercetin oligosaccharides (new feruloyl, sinapoyl and syringoyl derivatives of quercetin apiosylrhamnosylglucoside). (E)-β-Carotene and (E)-lycopene were also quantified along with different mono- and di-(Z)-isomers of lycopene which were tentatively assigned. Processing of fresh tomato into paste had an overall positive effect on the contents in phenolic compounds, no effect on lycopene and a slight and high detrimental effect on β-carotene and ascorbic acid, respectively. The balance between the increase in tomato matrix extractability and microconstituent catabolism was further observed in two contrasted transformations of paste into sauce. Overall, the nutritional quality of tomato-processed products, except for ascorbic acid, is mainly preserved through manufacture.     

Micronutrient contents in organic and conventional tomatoes (Solanum lycopersicum L.)

Organic food is associated by the general public with improved nutritional properties, and this has led to increasing demand for organic vegetables. The objective of this study was to investigate whether there were any differences in the micronutrient contents in organic and conventional tomatoes (Solanum lycopersicum L.). Two tomato cultivars ‘Lladó’ and ‘Antillas’ grown organically and conventionally were compared regarding their micronutrient in terms of K, Ca, Na, Mg, Fe, Zn, Mn, Cu, lycopene, ß‐carotene, ascorbic, malic and citric acids, and total phenolic compound content. Cultivar ‘Lladó’ had the highest concentration of the nutrient lycopene, ß‐carotene, Fe, Zn, Mn and Cu. Where cultivation method affected the concentration of ascorbic acid and Mn, only one cultivar was affected. For all nutrients examined, cultivar differences were greater than differences because of cultivation method. This study confirms that the most important variable in the micronutrient content of tomatoes is cultivar; organically grown tomato is no more nutritious than conventionally grown tomato when soil fertility is well managed.     

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.     

Evaluation of heat and oxidative damage during storage of processed tomato products. II. Study of oxidative damage indices

Tomato products (pulp, puree and paste) submitted to accelerated aging (30, 40 and 50 °C for 3 months) were studied to evaluate variations in the kinetics of the degradation of antioxidants and antioxidant activity. The carotenoids lycopene and β‐carotene, ascorbic acid, rutin and total phenolics were analysed. The antioxidant activity was measured using (a) the xanthine oxidase (XOD)/xanthine system, which generates superoxide radicals and hydrogen peroxide, and (b) the linoleic acid/CuSO₄ system, which promotes lipid peroxidation. The ascorbic acid content decreased even at 30 °C, following pseudo‐first‐order kinetics, with an activation energy of 105 200 J mol^?1 for tomato pulp and 23 600 J mol^?1 for tomato paste. The lower the initial ascorbic acid content, the higher was the degradation rate. Variations in phenolic compounds occurred at 40 °C and higher, following pseudo‐zero order kinetics. The antioxidant activity of the hydrophilic fraction of the tomato products depended on both antioxidant degradation and the Maillard reaction and could not be described by a kinetic model. The β‐carotene content decreased even at 30 °C, whereas the lycopene content was stable in all samples. The antioxidant activity of the lipophilic fraction of the tomato products decreased following pseudo‐first order kinetics, with an activation energy of 22 200 J mol^?1 for tomato pulp and 20 200 J mol^?1 for tomato paste. It is concluded that significant ‘oxidative damage’ can occur in tomato products during their commercial shelf‐life. Copyright © 2003 Society of Chemical Industry     

Development of a nutritional profile predicting tool for fresh and processed tomato‐based products

This study was aimed at developing a tool to represent the evolution of nutritional profile of food during processing with input data mined from previous published papers or database on composition and reactivity of nutrients, and from minimal experimentations. Tomato‐based products, that is tomato sauce, concentrate and paste, were chosen to evaluate the developed model. The SAIN‐LIM system was used to assess the nutritional profile of the tomato products throughout the process steps, including seven constituents: five basic nutrients (i.e. proteins, fibres, vitamin C, calcium and iron) and two microconstituents found in tomato: β‐carotene and lycopene. The SAIN‐LIM nutritional profiles obtained with this model were compared to that calculated from experimental data. Calculated and experimental nutritional scores showed that process steps involved in tomato‐based products did not affect substantially their nutritional quality. Observed differences were mainly attributed to the kinetic parameter selection and raw product variability. The conclusion offers suggestions to extend the model to other product/process combinations.     

Evaluation of the genotype, environment and their interaction on carotenoid and ascorbic acid accumulation in tomato germplasm

BACKGROUND: Tomatoes are an important source of antioxidants (carotenoids, vitamin C, etc.) owing to their high level of consumption. There is great interest in developing cultivars with increased levels of lycopene, β‐carotene or L ‐ascorbic acid. There is necessary to survey new sources of variation. In this study, the potential of improvement for each character in tomato breeding programmes, in a single or joint approach, and the nature of genotype (G), environment (E) and G × E interaction effects in the expression of these characters were investigated. RESULTS: The content of lycopene, β‐carotene and ascorbic acid determined was very high in some phenotypes (up to 281, 35 and 346 mg kg^?1 respectively). The important differences in the three environments studied (with some stressing conditions in several situations) had a remarkable influence in the phenotypic expression of the functional characters evaluated. Nevertheless, the major contribution came from the genotypic effect along with a considerable G × E interaction. CONCLUSION: The joint accumulation of lycopene and β‐carotene has a high genetic component. It is possible to select elite genotypes with high content of both carotenoids in tomato breeding programmes but multi‐environment trials are recommended. The improvement of ascorbic acid content is more difficult because the interference of uncontrolled factors mask the real genetic potential. Among the accessions evaluated, there are four accessions with an amazing genetic potential for functional properties that can be used as donor parents in tomato breeding programmes or for direct consumption in quality markets. Copyright © 2011 Society of Chemical Industry     

Profiling ellagic acid content: The importance of form and ascorbic acid levels

As the importance of plant-based antioxidants to human health becomes clearer there is a rapidly expanding search for rich sources of these compounds. Much attention is currently focussed on the antioxidant potential of ellagic acid (EA). Making assessment difficult is that EA occurs in different forms: free EA, EA glycosides and polymeric ellagitannins. The overall structure of these forms has a pronounced effect on their antioxidant efficiency and is responsible for widely differing reactivity, solubility and hence bioavailability properties. Often associated with EA is vitamin C which also contributes to the plant foods total antioxidant activity. Previous studies have suggested that ascorbic acid may have protective effects on the polyphenol content of plants. With a view to gaining evidence that the bioactive forms of vitamin C influence EA content, several fruits with a range of EA and vitamin C contents were examined. To facilitate a more detailed assessment of the selected fruits antioxidant potential the relative proportions of EA forms were also determined. In strawberries and boysenberries EA content was predominantly in the polymeric form (21% and 12% free EA plus EA glycoside vs total EA levels for strawberry and boysenberry respectively), while in Kakadu plum it was mainly in the free form (70% of total EA). An increasing percentage of dehydroascorbic acid (9 to 14% of total vitamin C) indicating enhanced transformation of ascorbic acid to its oxidative degradation product together with stable free EA levels (≈ 950 mg/100 g DW) over the 4 month frozen storage period for the Kakadu plum samples are consistent with a possible protective effect of EA by ascorbic acid.     

Effects of industrial tomato paste processing on ascorbic acid, flavonoids and carotenoids and their stability over one-year storage

BACKGROUND : The effects of industrial tomato paste processing and long‐term (12 months) ambient storage on the content and stability of quercetin, kaempferol, ascorbic acid (AA), dehydroascorbic acid (DHAA), β‐carotene and lycopene were evaluated in a commercially produced tomato paste. RESULTS : The initial thermal treatment (hot break; 93 °C for 5 min) resulted in significant reductions in quercetin (54%), kaempferol (61%), AA (63%) and β‐carotene (30%), whereas subsequent processing steps (e.g. evaporation and sterilization) did not result in marked changes in these compounds. Lycopene was stable during hot break but decreased by 20% through evaporation and sterilization. The ratio of DHAA:vitamin C increased during hot break to 23%, whereas the ratio of DHAA:vitamin C remained relatively low in subsequent processing steps, indicating that AA was not oxidized. AA decreased with prolonged storage, with only 13% remaining at 12 months. The carotenoids and quercetin remained stable through 12 months of ambient storage. CONCLUSIONS : Tomato pomace contained significant amounts of carotenoids and flavonoids, indicating that it may be an underutilized processing byproduct. Copyright © 2011 Society of Chemical Industry     

A study on thermal stability of lycopene in tomato in water and oil food systems using response surface methodology

Thermal processed tomato‐food products rich in Z‐lycopene isomers have demonstrated higher bioactivity compared to fresh products which contain mainly all‐E‐lycopene isomer. The objectives of this study were to optimise processing conditions for production of tomato products rich in Z‐lycopene isomers in water and oil systems. The results showed that the optimal conditions for water and oil systems were temperature 120 °C, heating time 2.14 h, and the percentage of Z‐lycopene isomers content was 51 ± 1% and 57 ± 2%, respectively. The ratio of tomato extract to oil/water had no influence on the Z‐lycopene formation. Therefore, from these results it can be concluded that the combination of high temperature and relatively short heat treatment time could improve formation of Z‐lycopene isomers or degradation of Z‐isomers is lower during tomato processing .These research results could be useful in assisting the industry to improve processing technology, nutritional value and health‐benefits of tomato‐based foods.     

High temperature-tolerant tomato lines: bioactive compounds

High global temperatures will be a great challenge for agricultural production in the near future. Therefore, adaptation of agricultural crops to the high temperatures or development of new heat-tolerant crops with known bioactive compounds is an important strategy for nutritional health and crop improvement programs. In this context, the bioactive compounds of newly developed high temperature-tolerant tomato lines were investigated in terms of lycopene, β-carotene, ascorbic acid and phenolic compounds to assist breeders for the selection of high temperature tolerant tomato varieties with high nutritional quality. Nineteen tomato lines, including control varieties from the “Turkey F1 Hybrid vegetable variety and quality line development” project and the GAP Agricultural Research Institute, were selected for the investigation. Line 11 was superior in lycopene and β-carotene content, while line 18 was superior in ascorbic acid content as compared to control varieties Cansun F1 and Alsancak RN F1. Urfa 2012 and line 28 were found to have the highest numbers of phenolic compounds. Chlorogenic acid, naringenin, trans-ferulic acid and rutin were key phenolic compounds detected in each of the tomato lines. These newly released tomato lines can be used as value-added germplasm or parent sources to develop new heat-tolerant cultivars in breeding programs or as commercial cultivars for their superior functional qualities.     

Dry fermented sausages enriched with lycopene from tomato peel

Tomato industries yield a high amount of by-products mainly tomato peel and seeds. Since tomato peel is rich in lycopene, the direct addition of peel to food products could be a way to use this by-product to obtain a new products enriched in lycopene. This work describes experiments performed to develop dry fermented sausages (salchichón) containing this carotene. 0%, 0.6%, 0.9% and 1.2% (w/w) of dry tomato peel was added to the meat mixture used in sausage manufacture. A slight losts of lycopene was detected after 21 days ripening, however, levels remained between 0.26 and 0.58 mg of lycopene/100 g of sausage. The sensory and textural properties and overall acceptability of all sausages were good, indicating that tomato peel could be added to dry fermented sausages to produce a meat product enriched in lycopene.     

Effect of moisture content, storage temperature and storage period on colour, ascorbic acid, lycopene and total flavonoids of dried tomato halves

Dried tomato halves with three storage moisture contents [18%, 24% and 30%, wet basis (wb)], packed in glass jar, plastic container and polyethylene bag were stored in room and cool-chamber environments for 5 months. During storage period average room and cool-chamber temperatures were 20 ± 4 and 5 ± 1 °C respectively. Changes of colour, ascorbic acid, lycopene, total flavonoids and moisture contents were monitored 1-month interval. Significantly higher losses of colour, ascorbic acid, lycopene and total flavonoids were found for room environment than those of cool chamber. A set of regression equations had been developed for colour, ascorbic acid, lycopene and total flavonoids as a function of storage time. No visible microorganisms were detected in the samples during the storage period. Dried tomato with ≤24% (wb) moisture content may be recommended to store in cool chamber (5 °C) and ≤18% (wb) to store in room environment (20 °C) both to be packed in glass jar.     

Effect of pilot-scale aseptic processing on tomato soup quality parameters

Tomatoes are often processed into shelf-stable products. However, the different processing steps might have an impact on the product quality. In this study, a model tomato soup was prepared and the impact of pilot-scale aseptic processing, including heat treatment and high-pressure homogenization, on some selected quality parameters was evaluated. The vitamin C content, the lycopene isomer content, and the lycopene bioaccessibility were considered as health-promoting attributes. As a structural characteristic, the viscosity of the tomato soup was investigated. A tomato soup without oil as well as a tomato soup containing 5% olive oil were evaluated. Thermal processing had a negative effect on the vitamin C content, while lycopene degradation was limited. For both compounds, high-pressure homogenization caused additional losses. High-pressure homogenization also resulted in a higher viscosity that was accompanied by a decrease in lycopene bioaccessibility. The presence of lipids clearly enhanced the lycopene isomerization susceptibility and improved the bioaccessibility. PRACTICAL APPLICATION: The results obtained in this study are of relevance for product formulation and process design of tomato-based food products.     

Degradation of Lycopene and β‐carotene in Model Systems and in Lyophilized Guava during Ambient Storage: Kinetics,Structure, and Matrix Effects

ABSTRACT: Being highly unsaturated, carotenoids are susceptible to isomerization and oxidation during the processing and storage of food. In the present study, the degradation of acyclic lycopene and dicyclic β‐carotene in low‐moisture and aqueous model systems, as well as in lyophilized guava, during storage at ambient temperature, in the absence or presence of light, was investigated. Both carotenoids followed first order kinetics under the various conditions investigated. Lycopene degraded much faster than β‐carotene in all the model systems. In a comparison of lycopene isolated from guava, tomato, and watermelon, greater losses were observed with lycopene from tomato. Since the model system was identical in the 3 cases, these results indicated that other compounds from the food sources, co‐extracted with lycopene, might have influenced the oxidation. Light consistently and strongly promoted degradation under all conditions studied. The susceptibility of lycopene to degradation was much less in lyophilized guava than in the model systems, showing the marked protective influence of the food matrix. Loss of β‐carotene, found at a concentration of about 18 times lower than lycopene, was only slightly lower than that of lycopene in lyophilized guava, indicating that the effect of matrix and/or the initial concentration overshadowed the structural influence.     

The anti-inflammatory effect of lycopene complements the antioxidant action of ascorbic acid and α-tocopherol

Tomato foods contain bioactive compounds, such as lycopene, ascorbic acid and α-tocopherol, which are assumed to show synergistic effects. The aim of the study was to investigate this presumed synergy. The effect on lipid peroxidation and inflammation was assessed. Lipid peroxidation was effectively inhibited by combinations of the compounds compared to the single compounds. Synergy between the combination of ascorbic acid and α-tocopherol was confirmed. Lycopene on its own effectively reduced inflammation by inhibiting the release of TNF-α and stimulating IL-10 production. The combination of lycopene, ascorbic acid and α-tocopherol tended to display a synergistic interaction on IL-10 production. Our observations highlight that lycopene mitigates inflammation, whereas ascorbic acid and α-tocopherol efficiently protect against lipid peroxidation. Both activities are complementary since they diminish the process of inflammation differently on different levels. In relation to health, this is an added value of fruit and vegetables such as tomato products that contain complementary bio-active compounds.     

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     

Lycopene extraction from tomato processing waste using ultrasound and cell-wall degrading enzymes

The tomato processing wastes are rich in lycopene pigment, which can be consumed as a natural food colorant and bioactive ingredient. The present study investigates the appropriateness of ultrasound pretreatment and enzymatic treatment with cellulase and pectinase enzymes to extract lycopene pigment from tomato processing wastes using response surface methodology (RSM). To achieve this goal, a central composite design consisting of four independent variables including cellulase concentration (0–10%), pectinase concentration (0–5%), ultrasonic time (0–60 min) and pH (3.5–5.5) was used to examine the influences of these process variables on the lycopene extraction. The second order model of lycopene extraction obtained from RSM analysis had the p value less than 0.001 and represented a coefficient of determination (R²) of 93.82%. Thus, a satisfactorily agreement between experimental and predicted values for lycopene content obtained by the second order model was observed. In addition, the Fourier Transform Infrared spectroscopy results did not show any destruction of functional groups of the investigated extracts containing lycopene pigment. Scanning electronic microscopy images from the remaining tomato processing wastes after treatment with more lycopene content extraction demonstrated more porous structure. These results implied that ultrasound-assisted enzymatic extraction was an efficient extracting method.     

Lycopene content of tomatoes and tomato products and their contribution to dietary lycopene

Tomatoes are an integral part of diet world wide. Many population studies have established link between dietary intake of tomatoes, a major source of a carotenoid antioxidant lycopene and reduced risk of chronic diseases. This study evaluates the lycopene contents of various commonly consumed tomato products and estimates its daily intake levels. A fast and simple spectrophotometric method for routine analysis of lycopene was developed and validated against HPLC method. Lycopene content in various tomato products ranged from 42 ppm to 365 ppm. Average daily dietary lycopene intake levels were assessed by administering food frequency questionnaire and were estimated to be 25.2 mg day⁻¹. Fresh tomatoes accounted for 50% of total lycopene intake.     

Effects of Post-Harvest Handling and Processing on Vitamin Contents of Peas

Vitamin contents of peas were measured at various stages of raw product handling, during 1976–1979 seasons, on different cultivars, on different sizes of peas, at various stages of processing, and at different processing plants. Some cultivar differences were shown in ascorbic acid, carotene, and folic acid, and different sizes of peas contained significantly different amounts of ascorbic acid, carotene, and thiamin contents. Profound effects were observed during blanching and thermal processing of peas. Ascorbic acid, thiamin, vitamin B₆, and niacin contents of canned peas were significantly (95% level) lower than those of fresh peas. Also some significant differences in vitamin contents of canned peas among different processing plants were observed.