Tomato pulp as source for the production of lycopene powder containing high proportion of cis-isomers

Cis-isomers of lycopene has been demonstrated to possess higher biological activity than its all-trans form. The objectives of this study were to compare the extraction efficiency and degree of isomerization of lycopene by employing supercritical carbon dioxide (SCD) and solvents, as well as process the lycopene extract into powder containing high proportion of cis-isomers from tomato pulp as source. Results showed that a high yield of lycopene was achieved by SCD at 350 bar and 70 °C, with cis-isomers making up 41.4% of total lycopene. However, with temperature at 80 and 90 °C, the maximum isomerization was accomplished, and cis-lycopene constituted 51.0 and 53.8% of total lycopene, respectively. For solvent extraction, the highest yield of all-trans-lycopene was attained by ethanol–hexane (4/3 v/v) at 25 and 50 °C, whereas the maximum isomerization (47.0% cis-lycopene) occurred at 75 °C. A powder product containing 34.5% cis-isomers of lycopene was obtained by spray-drying, and the total amount of lycopene in spray-dried powder was much greater than that in freeze-dried powder. The maximum yield of lycopene in the powder product could be obtained through processing by adding sodium alginate to the eluate directly after SCD extraction and open-column chromatography with formation of 41.4% cis-lycopene. The method developed in this study may be used for possible commercial production of highly active lycopene powder.     

Effect of illumination and chlorophylls on stability of tomato carotenoids

Lipidic extract from tomato peels, or tomato peels plus stalks, dissolved in ethanol were submitted to illumination. Lycopene, β-carotene, phytoene and phytofluene isomerisation and degradation, during storage at room temperature for 28 days, were studied. Degradation of chlorophylls a and b were analysed in lipidic extracts from stalks. Total lycopene and all-E-lycopene degradation was found to fit to a first-order model. The degradation rate constant was lower in extracts from peels −0.0137 (all-E-lycopene) and −0.0737 (total lycopene), than in those from peel plus stalk −0.0415 (all-E-lycopene) and −0.0854 (total lycopene). Z-lycopene isomers showed an inconsistence change during storage, in all analysed samples. Concentration of β-carotene from extracts of tomato peels plus stalks decreased slightly during storage. Phytoene and phytofluene degradation were not significantly affected by both storage conditions and chlorophylls. The obtained results showed that some compounds from stalks, such as chlorophylls, could favour lycopene and β-carotene degradation during storage under illumination.     

Improving the stability of lycopene Z-isomers in isomerised tomato extracts

Tomato-based foods rich in Z-lycopene are potentially more bioavailable and have greater bioefficacy compared to natural tomato products which mainly contain all-E-lycopene. To prepare a stable tomato extract with a high level of Z-lycopene, geometrical isomerisation of lycopene was studied in organic solvents either alone or in the presence of a tomato extract. Interconversion between the isomers was observed in all systems with 13Z-lycopene being the least stable. Heating a tomato extract containing mainly the all-E-isomer in ethyl acetate produced successively 13Z-, 9Z- and 5Z-lycopene. An isomerised tomato oleoresin with a minimal content of the most unstable 13Z-lycopene could be obtained by refluxing tomato oleoresin in ethyl acetate for 1 week. In this isomerised tomato oleoresin, total lycopene and lycopene isomer profiles were shown to remain constant for 1 year at room temperature. Accordingly, this product is a valid source of stable and potentially highly bioavailable lycopene.     

Effects of a hydrodynamic process on extraction of carotenoids from tomato

We evaluated the results of using a proprietary hydrodynamic method, which was introduced with the hope of increasing accessibility of beneficial nutrition-enhancing fruit and vegetable products. Tomato, a major dietary source of carotenoids, notably lycopene, was tested because of its many health benefits to consumers. Samples before and after treatment were compared for lycopene, phytoene, and phytofluene contents. Extractable lycopene and other carotenoids increased significantly. In nature, lycopene exists almost exclusively as the all-trans stereoisomer. Cis-lycopene isomers form during cooking and digestion, resulting in higher percentages in plasma and tissues than ingested. Cis-lycopene isomers are more bioavailable than all-trans lycopene. Extraction using this proprietary method increased extracted cis-lycopene to as high as 43% of the total lycopene, indicating increased isomerisation. This method could therefore contribute significantly to the delivery of health benefits of biologically available lycopene from tomato products for metabolic functions.     

Innovative extraction procedure for obtaining high pure lycopene from tomato

Many researchers have studied the biological effects of carotenoids and the more appropriate procedure for extracting them from vegetable sources. In this work we propose a rapid and low-cost procedure to extract lycopene from tomato in order to by-pass the problems related to the high cost of this molecule. Following this procedure we have obtained over 95% pure all-trans-lycopene checked by DAD-HPLC coupled with mass-spectrometer equipped with APCI source and by UV–Vis spectroscopy. Moreover, in order to evaluate the effectiveness of this procedure, we have assayed the capacity of the extracted lycopene to inhibit proliferation in T-lymphocyte jurkat J32 cells in comparison with authentic standard all-trans-lycopene. On this cellular line both standard lycopene and extracted lycopene tended to be dose-dependent but this latter seems to be more active even at lowest concentration.     

Influence of extraction with ethanol or ethyl acetate on the yield of lycopene, β-carotene,phytoene and phytofluene from tomato peel powder

This study evaluated the extraction yield of the food grade solvents ethanol and ethyl acetate by extracting lycopene, β-carotene, phytoene and phytofluene from tomato peel powder at varying heating intensities, and the influence of the solvent and heating intensity on carotenoids isomerization and degradation during extraction. The heat treatments assayed were 25, 35, 50 and 60 °C which were applied for periods of 5, 10, 20, 30 or 40 min. The carotenoid yield was higher in the extractions with ethanol than with ethyl acetate. In general, the temperature increase caused an increase in the carotenoid concentrations; however in the extractions performed with ethanol at 60 °C, the yield of (all-E)-lycopene and their (Z)-isomers was lower than at 50 °C. This could indicate that a great isomerization is produced in the high temperature extractions with ethanol but the oxidative degradation is the predominant reaction. On the contrary, the obtained results in the extractions with ethyl acetate indicate that the isomerization is the predominant reaction.     

Thermal processing of carrots: Lycopene stability and isomerisation with regard to antioxidant potential

The thermal stability of lycopene was evaluated in a carrot cultivar with a high lycopene content (Daucus carota var. Nutri Red) by (a) exposure of carrot homogenates (with/without the addition of oil) to temperatures ranging from 25 to 140 °C; (b) applying convection and microwave vacuum drying to carrot slices. Heating carrot homogenates at temperatures above 100 °C initiated isomerisation of all-trans-lycopene under non-oxidising conditions, as indicated by a significant increase in 9-cis-lycopene. Isomerisation was enhanced at short treatment times, when sunflower oil was added prior to thermal treatment. Independent from an oil supplement, all-trans-lycopene was degraded at temperatures above 70 °C. The ratio of all-trans- to total-cis-isomers changed from 90:10 to 40:60, indicating a higher lycopene bioavailability due to generated cis-isomers. In oil containing carrot homogenates antioxidant properties of the methanol-soluble components raised after heat treatment at 130 °C for 0.5 h. Lycopene remained stable in dried carrots.     

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.     

Volatile chemical and carotenoid profiles in watermelons [Citrullus vulgaris (Thunb.) Schrad (Cucurbitaceae)] with different flesh colors

Twelve watermelon [Citrullus vulgaris (Thunb.) Schrad (Cucurbitaceae)] cultivars with different flesh colors were analyzed by HPLC, GC-FID, and GC-MS for their differences in carotenoid, soluble sugar, organic acid, and flavor. Results showed that all-trans violaxanthin, 9-cis-violaxanthin, and luteoxanthin were the main carotenoid esters in watermelons with yellow flesh. However, watermelons with red flesh were rich in all-trans lycopene and their cis-isomers. High concentrations of β-carotene and pro-lycopenes were found in watermelon with orange-yellow flesh. Large variations in the sucrose concentration were observed among the different watermelons. Sucrose and/or fructose were the dominant sugars, while citric acid and malic acid were the main organic acids in watermelon flesh. Limonene was detected in the watermelon flesh of all investigated genotypes. Interestingly, partial correlation analysis of the chemical concentrations revealed 2 significant (p<0.01) positive correlations between β-ionone and β-carotene, and between (E)-geranyl acetone and prolycopenes.     

Cis-trans isomerisation of lycopene and colour stability of foam—mat dried tomato powder during storage

Tomato powder with ～3% moisture was obtained by foam-mat drying tomato paste (29% solids). Samples of powder were stored at various temperatures (?10° +2° +20° and +37°c), atmospheres (air, nitrogen) and humidities (with and without in-package desiccation), and colour changes were observed for periods of up to 1 year. The main cause of colour fading was the oxidation of lycopene. However, another phenomenon, trans—cis isomerisation of all-trans lycopene, can occur, with apparent loss of coloration, which is later restored by re-isomerisation. The existence of this mechanism was demonstrated by simultaneous measurements of total liposoluble colour at 420 nm and separations of carotenoid pigments by column chromatography on Al₂O₃. Neo-lycopene A (6-mono-cis-lycopene) and at least one other cis-lycopene isomer were found in fresh powder and in samples stored up to 5 months. cis-Isomers were more susceptible to oxidation. Colour changes depend upon the interplay of isomerisation and oxidation; in some cases, tomato powder was more intensively coloured after storage than when fresh. Storage at +20°c was more favourable for colour retention than storage at +2°c, or — 10°c. Excessive desiccation strongly promoted oxidation losses. Storage in an inert atmosphere improved colour retention. At +37°c non-enzymic browning, accompanied by formation of water, caused rapid darkening although carotenoid pigments were not lost to a great extent.     

Lycopene in tomatoes: chemical and physical properties affected by food processing

Lycopene is the pigment principally responsible for the characteristic deep-red color of ripe tomato fruits and tomato products. It has attracted attention due to its biological and physicochemical properties, especially related to its effects as a natural antioxidant. Although it has no provitamin A activity, lycopene does exhibit a physical quenching rate constant with singlet oxygen almost twice as high as that of beta-carotene. This makes its presence in the diet of considerable interest. Increasing clinical evidence supports the role of lycopene as a micronutrient with important health benefits, because it appears to provide protection against a broad range of epithelial cancers. Tomatoes and related tomato products are the major source of lycopene compounds, and are also considered an important source of carotenoids in the human diet. Undesirable degradation of lycopene not only affects the sensory quality of the final products, but also the health benefit of tomato-based foods for the human body. Lycopene in fresh tomato fruits occurs essentially in the all-trans configuration. The main causes of tomato lycopene degradation during processing are isomerization and oxidation. Isomerization converts all-trans isomers to cis-isomers due to additional energy input and results in an unstable, energy-rich station. Determination of the degree of lycopene isomerization during processing would provide a measure of the potential health benefits of tomato-based foods. Thermal processing (bleaching, retorting, and freezing processes) generally cause some loss of lycopene in tomato-based foods. Heat induces isomerization of the all-trans to cis forms. The cis-isomers increase with temperature and processing time. In general, dehydrated and powdered tomatoes have poor lycopene stability unless carefully processed and promptly placed in a hermetically sealed and inert atmosphere for storage. A significant increase in the cis-isomers with a simultaneous decrease in the all-trans isomers can be observed in the dehydrated tomato samples using the different dehydration methods. Frozen foods and heat-sterilized foods exhibit excellent lycopene stability throughout their normal temperature storage shelf life. Lycopene bioavailability (absorption) can be influenced by many factors. The bioavailability of cis-isomers in food is higher than that of all-trans isomers. Lycopene bioavailability in processed tomato products is higher than in unprocessed fresh tomatoes. The composition and structure of the food also have an impact on the bioavailability of lycopene and may affect the release of lycopene from the tomato tissue matrix. Food processing may improve lycopene bioavailability by breaking down cell walls, which weakens the bonding forces between lycopene and tissue matrix, thus making lycopene more accessible and enhancing the cis-isomerization. More information on lycopene bioavailability, however, is needed. The pharmacokinetic properties of lycopene remain particularly poorly understood. Further research on the bioavalability, pharmacology, biochemistry, and physiology must be done to reveal the mechanism of lycopene in human diet, and the in vivo metabolism of lycopene. Consumer demand for healthy food products provides an opportunity to develop lycopene-rich food as new functional foods, as well as food-grade and pharmaceutical-grade lycopene as new nutraceutical products. An industrial scale, environmentally friendly lycopene extraction and purification procedure with minimal loss of bioactivities is highly desirable for the foods, feed, cosmetic, and pharmaceutical industries. High-quality lycopene products that meet food safety regulations will offer potential benefits to the food industry.     

Measurement of Glycosylated Vitamin B6 in Foods

To examine the levels of glycosylated vitamin B6 in 22 foods, each food was stirred for 2 hr at pH 6.8 and then incubated for 2 hr at pH 5.0 and 37°C with β-glucosidase (60 units per g food). Vitamin B6 content of foods was measured microbiologically before and after enzyme treatment as well as with acid hydrolysis. Animal products contained no measurable amount of glycosylated B6. Grains and legumes generally had a high level of this bound form (6–57% of the total vitamin B6). Of the fruits analyzed, orange juice had the highest level of glycosylated vitamin B6 (47%). Among fresh vegetables studied, raw carrots had the highest level (51%). For broccoli and cauliflower, the glycosylated value was higher for the processed food as compared to the raw food.     

Determination of vitamins A and E in cooked sausages

A reliable and sensitive reverse-phase HPLC method is described for the separation and quantification of all-trans-retinol and dl-α-tocopherol in cooked sausages. Samples were chromatographed with UV and fluorescence detection on a 15 cm × 0.4 cm i.d. Spherisorb ODS-2, 5 μm column, using as mobile phase a mixture of 90% acetonitrile and 10% tetrahydrofuran. Sample preparation included saponification and extraction by n-hexane. Addition of pyrogallol and oxygen-free conditions avoided oxidation of both vitamins, increasing recovery percentages, which ranged from 90.0 to 95.0%. Precision was 1.0% (within a day) and 3.4% (between days) for all-trans-retinol and 1.1% (within a day) and 2.6% (between days) for dl-α-tocopherol. Detection limits were 10 μg/100 g for all-trans-retinol and 0.1 mg/100 g for dl-α-tocopherol with a signal-to-noise ratio of 3. Twenty samples of six different products were analyzed in duplicate. Average for all-trans-retinol in “enriched chopped” was 108 mg/100 g fresh weight, and the mean value for dl-α-tocopherol in “enriched chopped” was 2.3 mg/100 g fresh weight.     

Comparison of thermal,ultraviolet-c,and high pressure treatments on quality parameters of watermelon juice

The effect of thermal, ultraviolet-c, and high pressure treatments on colour, browning degree, dynamic viscosity, and lycopene content of watermelon juice was evaluated based on its pectin methylesterase residual level. Each treatment had a different impact on parameters studied. Ultraviolet-c treatments were rapid and effective to inactivate the pectin methylesterase of the watermelon juice compared to the thermal and high pressure treatments in the same time and temperature. High pressure treatments at 600 MPa kept the colour of the treated watermelon juice close to an untreated one, and that at 600–900 MPa held the browning degree and dynamic viscosity of the treated watermelon juice comparable to an untreated one. Moreover, the high pressure treatment had a slight impact on the all-trans-lycopene, total cis-lycopene, and total lycopene concentration of the watermelon juice compared to the other treatments. In summary, the high pressure treatment showed the lowest changes in colour, dynamic viscosity, browning degree, and lycopene content of the treated watermelon juice amongst the three treatments.     

Validation of HPLC method for determination of E- and Z-Ajoene in oil-macerated garlic juice

HPLC method for determination of ajoene isomers in garlic oil products was optimized and validated. E- and Z-Ajoene were extracted with ethyl acetate and followed by the sensitive and selective determination of 2 isomers in a single run using normal phase HPLC equipped with silica gel column. The mobile phase was n-hexane and 2-propanol (85/15, v/v) with an isocratic condition as a flow rate of 1.0 mL/min and 240 nm of HPLC UV detector. All calibration curves of E- and Z-ajoene in oil-macerated garlic showed good linearity (r=0.998). Overall, intra- and inter-day were in the range of 0.12–2.30 and 2.84–5.26%, respectively. Recovery was in range of 87.17–98.53% for E-ajoene and 85.16–99.23% for Z-ajoene. The validated method was applied to determine contents of ajoene in macerate garlic juices prepared with various vegetable oil. There were no any matrix effects in all chromatograms. The proposed method may be useful for quality control and evaluation of garlic oil products.     

Detection of Melamine in Gluten,Chicken Feed,and Processed Foods Using Surface Enhanced Raman Spectroscopy and HPLC

ABSTRACT: Melamine, a nitrogen‐rich chemical, was implicated in pet and human food recalls in 2007, which caused enormous economic losses to the food industry. In this study, melamine concentration in wheat gluten, chicken feed, and processed foods (that is, cake and noodle) was measured by surface enhanced Raman spectroscopy (SERS) in combination with SERS‐active substrates. SERS was able to rapidly detect 0.1% melamine in wheat gluten, 0.05% in chicken feed, 0.05% in cakes, and 0.07% in noodle, respectively. A partial least squares (PLS) model was established for the quantification of melamine in foods by SERS: R= 0.90, RMSEP = 0.33. In addition, SERS results were verified by HPLC analysis based on a simplified FDA method. Compared with HPLC, the SERS method is much faster and simpler, requires minimum sample preparation, but still yields satisfactory qualitative and quantitative results. These results demonstrate that it is an applicable approach to use SERS to screen foods, eliminate presumptive negative samples of melamine contamination from the sample population, and then verify presumptive positive samples using HPLC protocols. Combining these 2 methods could provide a more rapid and cost‐effective way for monitoring melamine contamination in increasingly large numbers of imported foods and feed products.     

Enhanced E/Z Isomerization of (All‐E)‐lycopene by Employing Iron(III) Chloride as a Catalyst

Catalytic isomerization of (all‐E)‐lycopene to Z‐isomers using iron(III) chloride was investigated and optimized under various conditions of solvents, concentrations of iron(III) chloride, and reaction temperatures. The total contents of Z‐isomers converted were higher in the order of CH₂Cl₂ (78.4%) > benzene (61.4%) > acetone (51.5%) > ethyl acetate (50.8%) at 20 °C for 3 h using 1.0 × 10^?3 mg/mL iron(III) chloride for 0.1 mg/mL (all‐E)‐lycopene. However, the decomposition of lycopene was markedly accelerated in CH₂Cl₂: the remaining lycopene after the reaction for 3 h and 12 h was only 79.4% and 47.5%, respectively. As the concentration of catalyst increased in acetone, the Z‐isomerization ratio of lycopene increased to more than 80%, followed by rapid degradation of lycopene to undetectable levels using >4.0 × 10^?3 mg/mL iron(III) chloride with the above concentration of (all‐E)‐lycopene. Finally, greater isomerization (79.9%) was attained at 60 °C in acetone for 3 h in the presence of 1.0 × 10^?3 mg/mL iron(III) chloride, largely without decomposition of lycopene (remaining ratio of total amount of lycopene isomers after the reaction, 96.5%). As iron(III) chloride has found general use as a food additive for iron fortification and acetone is also widely used in the food field, this method can be applied to the food and beverage processing industry.     

Balanced diets in food systems: Emerging trends and challenges for human health

ABSTRACT

Processed foods, generally known as modified raw foods produced by innovative processing technologies alters the food constituents such natural enzymes, fatty acids, micronutrients, macronutrients and vitamins. In contrast to fresh and unprocessed foods, processed foods are guaranteed to be safer, imperishable, long lasting and consist high level of nutrients bioactivity. Currently, the evolution in food processing technologies is necessary to face food security and safety, nutrition demand, its availability and also other global challenges in the food system. In this scenario, this review consists of information on two food processing technologies, which effects on processed foods before and after processing and the impact of food products on human health. It is also very well established that understanding the type and structure of foods to be processed can assist food processing industries towards advancement of novel food products. In connection with this fact, the present article also discusses the emerging trends and possible modifications in food processing technologies with the combination of conventional and modern techniques to get the suitable nutritional and safety qualities in food.     

Aluminium content of some processed foods,raw materials and food additives in China by inductively coupled plasma–mass spectrometry

The level of aluminium in 178 processed food samples from Shenzhen city in China was evaluated using inductively coupled plasma–mass spectrometry. Some processed foods contained a concentration of up to 1226?mg/kg, which is about 12 times the Chinese food standard. To establish the main source in these foods, Al levels in the raw materials were determined. However, aluminium concentrations in raw materials were low (0.10–451.5?mg/kg). Therefore, aluminium levels in food additives used in these foods was determined and it was found that some food additives contained a high concentration of aluminium (0.005–57.4?g/kg). The results suggested that, in the interest of public health, food additives containing high concentrations of aluminium should be replaced by those containing less. This study has provided new information on aluminium levels in Chinese processed foods, raw materials and a selection of food additives.     

泉州市食品中单核细胞增生李斯特氏菌的定性、定量及耐药性分析

为了解福建省泉州市食品中单增李斯特氏菌的污染状况，于2000年12月至2001年12月对泉州市市售的155份生肉、熟肉制品、水产品中的单增李斯特氏菌进行了定性，定量及耐药性测定，检出李斯特氏菌47株，总检出率为35．48％，其中生肉类68．12％，海产品类12．5％，熟肉类6．52％，检出单增李斯特氏菌6株，总检出率3．87％，其中生肉类8．7％，海产品和类熟肉类中未检出。6株单增李斯特氏菌均对氨苄西林，头孢噻吩、氯洁霉素，氧氟沙星，青霉素G、四环素，万古霉素敏感，对环丙沙星中度敏感，对呋喃妥因不敏感，根据测定结果，建议有关部门及早制定相应的管理措施，加强监测，防止其引起的食中毒爆发流行。