Impact of high pressure and pulsed electric fields on bioactive compounds and antioxidant activity of orange juice in comparison with traditional thermal processing

Bioactive compounds (vitamin C, carotenoids, and flavanones) and DPPH* radical scavenging capacity (RSC) were measured in orange juice (OJ) subjected to different technologies. High pressure (HP) (400 MPa/40 degrees C/1 min), pulsed electric fields (PEF) (35 kVcm(-1)/750 micros), low pasteurization (LPT) (70 degrees C/30 s), high pasteurization (HPT) (90 degrees C/1 min), HPT plus freezing (HPT+F) (-38 degrees C/15 min), and freezing (F) were studied. Among the treatments assayed, even though the losses in total vitamin C were < 9%, treatments with the higher temperatures tended to show the higher decrease in the content of both forms of vitamin C. HP treatment led to an increased (P < 0.05) carotenoid release (53.88%) and vitamin A value (38.74%). PEF treatment did not modify individual or total carotenoids content. Traditional thermal treatments did not exert any effect on total carotenoid content or vitamin A value. With regard to individual carotenoid extraction, HPT and HPT+F led to different releases of carotenoids. With respect to flavanones, HP treatment led to increased (P < 0.05) naringenin (20.16%) and hesperetin (39.88%) contents, whereas PEF treatment did not modify flavanone content. In general, pasteurization and freezing process led to a diminished (P < 0.05) naringenin content (16.04%), with no modification in hesperetin. HP and PEF treatments did not modify DPPH* RSC. In the case of traditional thermal technologies, HPT treatment showed a decrease (P < 0.05) in RSC (6.56%), whereas LPT, HPT+F, and F treatments did not modify RSC. Vitamin C modulated RSC, in terms of antioxidant concentration (EC50) and kinetics (AE = 1/EC50TEC50), in the treated and untreated OJ. In summary, HP and PEF technologies were more effective than HPT treatment in preserving bioactive compounds and RSC of freshly squeezed orange juice.     

Effect of high-pressure treatment on the carotenoid composition and the radical scavenging activity of persimmon fruit purees

The carotenoid composition of persimmon fruit purees of two cultivars, cvs. Rojo Brillante and Sharon, grown in Spain was determined by HPLC to assess the effects of high-pressure processing on some sensory (carotenoids), nutritional (provitamin A value), and health-related (radical-scavenging capacity) parameters. Total carotenoid content was higher in untreated Rojo Brillante puree (22. 11 microg g(-)(1)) than in untreated Sharon puree (15.22 microg g(-)(1)). Purees of both untreated cultivars showed similar carotenoid patterns after saponification with beta-cryptoxanthin, beta-carotene, and zeaxanthin as the main pigments. A high content of lycopene was quantified in Rojo Brillante (5.34 microg g(-)(1)), whereas only traces were detected in Sharon. The provitamin A value, reported as retinol equivalents (RE), was in untreated Rojo Brillante puree (77 RE/100 g) similar to that of Sharon (75 RE/100 g). Scavenging free radical capacity, measured as antiradical efficiency (AE), showed in untreated Rojo Brillante puree a value (12.14 x 10(-)(3)) 8.5 times higher than that in untreated Sharon (1. 42 x 10(-)(3)). Nonuniform behavior of high-pressure treatment was detected. Pressure treatments at 50 and 300 MPa/15 min/25 degrees C for Rojo Brillante and at 50 and 400 MPa/15 min/25 degrees C for Sharon increased the amount of extractable carotenoids (9-27%), which are related with the increase of vitamin A value (75-87 RE/100 g). No correlation with the increase of AE (from 1.42 x 10(-)(3) to 16.73 x 10(-)(3) and 19.58 x 10(-)(3)) after some pressure treatments (150 and 300 MPa/15 min/25 degrees C) was found.     

Carotenoid profile modification during refrigerated storage in untreated and pasteurized orange juice and orange juice treated with high-intensity pulsed electric fields

A comparative study was made of the evolution and modification of various carotenoids and vitamin A in untreated orange juice, pasteurized orange juice (90 degrees C, 20 s), and orange juice processed with high-intensity pulsed electric fields (HIPEF) (30 kV/cm, 100 micros), during 7 weeks of storage at 2 and 10 degrees C. The concentration of total carotenoids in the untreated juice decreased by 12.6% when the juice was pasteurized, whereas the decrease was only 6.7% when the juice was treated with HIPEF. Vitamin A was greatest in the untreated orange juice, followed by orange juice treated with HIPEF (decrease of 7.52%) and, last, pasteurized orange juice (decrease of 15.62%). The decrease in the concentrations of total carotenoids and vitamin A during storage in refrigeration was greater in the untreated orange juice and the pasteurized juice than in the juice treated with HIPEF. During storage at 10 degrees C, auroxanthin formed in the untreated juice and in the juice treated with HIPEF. This carotenoid is a degradation product of violaxanthin. The concentration of antheraxanthin decreased during storage, and it was converted into mutatoxanthin, except in the untreated and pasteurized orange juices stored at 2 degrees C.     

Thermal degradation of antioxidant micronutrients in citrus juice: kinetics and newly formed compounds

The thermal degradation kinetics of vitamin C, two carotenoids (beta-carotene and beta-cryptoxanthin), and hesperidin, as a function of temperature, were determined for Citrus juice [Citrus sinensis (L.) Osbeck and Citrus clementina Hort. ex Tan]. The influence of dissolved oxygen on the rate of ascorbic acid degradation was also assessed. Analysis of kinetic data suggested a first-order reaction for the degradation of vitamin C and carotenoids. The kinetics parameters Dtheta, z, and Ea have been calculated. Following the Arrhenius relationship, the activation energy of ascorbic acid was 35.9 kJ mol-1 and agreed with the range of literature reported value. The results on vitamin C and carotenoids from citrus juice made it possible to validate the predicting model. Thermal degradation of carotenoids revealed differences in stability among the main provitamin A carotenoids and between these and other carotenoids belonging to the xanthophyll family. The activation energies for the two provitamin A carotenoids were 110 and 156 kJ mol-1 for beta-carotene and beta-cryptoxanthin, respectively. On the other hand, no degradation of hesperidin was observed during thermal treatment. Finally, the vitamin C in citrus juice was not as heat sensitive as expected and the main provitamin A carotenoids present in citrus juice displayed a relative heat stability. The high-performance liquid chromatography-diode array detection-mass spectrometry analysis of degradation products showed that the isomerization of the epoxide function in position 5,6 into a furanoxide function in position 5,8 was a common reaction for several xanthophylls. These findings will help determine optimal processing conditions for minimizing the degradation of important quality factors such as vitamin C and carotenoid in citrus juice.     

Simultaneous extraction and quantitation of carotenoids, chlorophylls, and tocopherols in Brassica vegetables

Brassica oleracea vegetables, such as broccoli (B. oleracea L. var. italica) and cauliflower (B. oleracea L. var. botrytis), are known to contain bioactive compounds associated with health, including three classes of photosynthetic lipid-soluble compounds: carotenoids, chlorophylls, and tocopherols. Carotenoids and chlorophylls are photosynthetic pigments. Tocopherols have vitamin E activity. Due to genetic and environmental variables, the amounts present in vegetables are not constant. To aid breeders in the development of Brassica cultivars with higher provitamin A and vitamin E contents and antioxidant activity, a more efficient method was developed to quantitate carotenoids, chlorophylls, and tocopherols in the edible portions of broccoli and cauliflower. The novel UPLC method separated five carotenoids, two chlorophylls, and two tocopherols in a single 30 min run, reducing the run time by half compared to previously published protocols. The objective of the study was to develop a faster, more effective extraction and quantitation methodology to screen large populations of Brassica germplasm, thus aiding breeders in producing superior vegetables with enhanced phytonutrient profiles.     

Identification and quantification of carotenoids, by HPLC-PDA-MS/MS, from Amazonian fruits

The major and minor carotenoids from six fruits, buriti (Mauritia vinifera), mamey (Mammea americana), marimari (Geoffrola striata), peach palm (Bactrys gasipaes), physalis (Physalis angulata), and tucuma (Astrocaryum aculeatum), all native to the Amazonia region, were determined by high-performance liquid chromatography-photodiode array detector-mass spectrometry detector (HPLC-PDA-MS/MS), fulfilling the recommended criteria for identification. A total of 60 different carotenoids were separated on a C30 column, all-trans-beta-carotene being the major carotenoid found in all fruits. The presence of apo-10'-beta-carotenol, found in mamey, was not previously reported in foods. In addition, this is the first time that the identification of beta-zeacarotene in natural sources is supported by MS data. The total carotenoid content ranged from 38 microg/g in marimari to 514 microg/g in buriti. All fruits analyzed can be considered good sources of provitamin A, especially buriti, with 7280 RE/100 g.     

Production system and storage temperature influence grapefruit vitamin C, limonoids, and carotenoids

Concentrations of grapefruit (cv. 'Rio Red'; Citrus paradisi Macf.) bioactives grown under organic and conventional production systems were evaluated after storage at various temperatures. The first experiment was conducted in November 2008 and the second experiment was conducted in February 2011 using commercial production, processing, and packing procedures. The harvested grapefruits were stored at 23 °C (room temperature) or 9 °C for 4 weeks and analyzed for vitamin C, limonoids, and carotenoids at the end of each week using HPLC. Vitamin C levels were higher in organically grown grapefruits (41.8 mg/100 g) compared to conventionally grown grapefruits (39.2 mg/100 g) at 0 days after harvest in the first experiment. However, production system did not significantly affect vitamin C levels in the second experiment. During storage at room temperature, vitamin C degradation losses ranged from 0.5 to 7% for organically produced grapefruits and from 3 to 18% for conventional grapefruits in both experiments. In the first experiment at harvest, organically produced grapefruits had 77% higher (p ≤ 0.05) nomilin than conventionally produced grapefruits, whereas grapefruits grown under the conventional production system had 2-fold higher lycopene levels compared to organic grapefruits. In the second experiment, both β-carotene and lycopene levels were significantly (p ≤ 0.05) higher in conventionally produced grapefruits than in organic grapefruits. Overall, conventional production significantly increased grapefruit carotenoid levels in both experiments. In general, storage temperature (room temperature and 9 °C) had minimal effects on vitamin C degradation but significant effects on the degradation of carotenoids in the first experiment.     

Carotenoid content of pandanus fruit cultivars and other foods of the Republic of Kiribati

BACKGROUND: Kiribati, a remote atoll island country of the Pacific, has serious problems of vitamin A deficiency (VAD). Thus, it is important to identify locally grown acceptable foods that might be promoted to alleviate this problem. Pandanus fruit (Pandanus tectorius) is a well-liked indigenous Kiribati food with many cultivars that have orange/yellow flesh, indicative of carotenoid content. Few have been previously analysed. AIM: This study was conducted to identify cultivars of pandanus and other foods that could be promoted to alleviate VAD in Kiribati. METHOD: Ethnography was used to select foods and assess acceptability factors. Pandanus and other foods were analysed for beta- and alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, lycopene and total carotenoids using high-performance liquid chromatography. RESULTS: Of the nine pandanus cultivars investigated there was a great range of provitamin A carotenoid levels (from 62 to 19,086 microg beta-carotene/100 g), generally with higher levels in those more deeply coloured. Seven pandanus cultivars, one giant swamp taro (Cyrtosperma chamissonis) cultivar and native fig (Ficus tinctoria) had significant provitamin A carotenoid content, meeting all or half of estimated daily vitamin A requirements within normal consumption patterns. Analyses in different laboratories confirmed high carotenoid levels in pandanus but showed that there are still questions as to how high the levels might be, owing to variation arising from different handling/preparation/analytical techniques. CONCLUSIONS: These carotenoid-rich acceptable foods should be promoted for alleviating VAD in Kiribati and possibly other Pacific contexts where these foods are important. Further research in the Pacific is needed to identify additional indigenous foods with potential health benefits.     

Bioaccessibility of tocopherols, carotenoids, and ascorbic acid from milk- and soy-based fruit beverages: influence of food matrix and processing

A study was made of the effect of high-pressure processing (HPP) and thermal treatment (TT) on plant bioactive compounds (tocopherols, carotenoids, and ascorbic acid) in 12 fruit juice-milk beverages and of how the food matrix [whole milk (JW), skimmed milk (JS), and soy milk (JSy)] modulates their bioaccessibility (%). HPP (400 MPa/40 °C/5 min) produced a significant decrease in carotenoid and ascorbic acid bioaccessibility in all three beverages and maintained the bioaccessibility of tocopherols in JW and JS while decreasing it in JSy. TT (90 °C/30 s) produced a significant decrease in tocopherol and carotenoid bioaccessibility in all three beverages and increased the bioaccessibility of ascorbic acid. With regard to the food matrix, α-tocopherol and ascorbic acid bioaccessibility was greatest in JW beverages and lowest in JSy beverages, whereas no significant differences were found among the three beverages in terms of carotenoid bioaccessibility. HPP-treated samples showed higher tocopherol and carotenoid bioaccessibility than TT-treated samples, thus indicating that HPP combined with a milk matrix positively modulates the bioaccessibility of certain types of bioactive components of food, mainly those of a lipophilic nature.     

Effect of storage temperature on the degradation of dimethoate in fortified orange and peach juices

The effect of storage temperature on dimethoate degradation in fortified orange and peach juices was studied. The insecticide was aseptically injected into packed orange and peach juices and stored at 40, 15, and 0 degrees C. Samples were taken at regular time intervals and were examined for dimethoate residues. The residues were determined with a simple gas chromatographic method; the recoveries of dimethoate from orange and peach juices were found to be from 88 to 114% for both products. The limits of determination were 0.004 and 0.003 mg/kg, respectively. From the experimental data, rate constants, half-lives, and activation energies for the decomposition of dimethoate in orange and peach juices were evaluated. During the storage of fruit juices in refrigerated rooms (0 degrees C) half-lives of dimethoate were found to be largely extended, being 1733 days for orange juice and 2310 days for peach juice. Corresponding times for storage at 15 degrees C were 533 days for both juices and for storage at 40 degrees C 24 days for orange juice and 24.6 days for peach juice. The activation energy for dimethoate in orange juice was 22.3 kcal/mol and for peach juice, 21. 2 kcal/mol.     

Effect of orange juice's processing on the color, particle size, and bioaccessibility of carotenoids

This study was aimed at assessing the differences between industrially processed and hand-squeezed orange juices (OJs) in relation to their color, particle size, carotenoid content, and carotenoid bioaccessibility. Specifically, industrial samples of fresh squeezed OJs after the finishing steps (FISO) and the same OJs after pasteurization (PISO), as well as hand-squeezed OJs (HSO) were studied. The results showed that the HSO and PISO were different (p < 0.05) in terms of color (darker and more reddish vs brighter, more yellowish and colorful), particle size (volume and surface area mean diameter), and total carotenoid content (29 ± 5 and 22 ± 3 mg/L, respectively). On the other hand, the industrial extraction of OJs reduced the particle size distribution, and accordingly, the relative bioaccessibility of bioactive carotenoids increased (p < 0.01). Independently of the type of OJ, the bioaccessibility of carotenoids in decreasing order was the following: α-carotene > β-cryptoxanthin > β-carotene > zeaxanthin > lutein.     

Effect of high-intensity pulsed electric fields processing and conventional heat treatment on orange-carrot juice carotenoids

Liquid chromatography (LC) was the method of choice for quantification of carotenoids (including geometrical isomers) to evaluate the effects of high-intensity pulsed electric field (HIPEF), a nonthermal preservation method, with different parameters (electric field intensities and treatment times), on an orange-carrot juice mixture (80:20, v/v). In parallel, a conventional heat treatment (98 degrees C, 21 s) was applied to the juice. HIPEF processing generally caused a significant increase in the concentrations of the carotenoids identified as treatment time increased. HIPEF treatment at 25 and 30 kV/cm provided a vitamin A concentration higher than that found in the pasteurized juice.     

The xanthophyll composition of biofortified maize (Zea mays Sp.) does not influence the bioefficacy of provitamin a carotenoids in Mongolian gerbils (Meriones unguiculatus)

Maize has been targeted for biofortification with provitamin A carotenoids through traditional breeding. Two studies were conducted in gerbils to evaluate factors that may affect provitamin A activity. Maize diets had equal theoretical concentrations of vitamin A (VA) assuming 100% bioefficacy. Study 1 ( n = 57) varied the ratio of beta-cryptoxanthin and beta-carotene but maintained the same theoretical VA. Study 2 ( n = 67) varied lutein and zeaxanthin. Other treatments were oil, VA, or beta-carotene doses. Serum and livers were analyzed for VA and carotenoids. In study 1, total liver VA did not differ among the maize groups. In study 2, total liver VA of the VA and maize groups were higher than controls ( P < 0.05). Conversion factors were 2.1-3.3 mug beta-carotene equivalents to 1 mug retinol. Twice the molar amount of beta-cryptoxanthin was as efficacious as beta-carotene and the proportion of beta-cryptoxanthin or xanthophylls did not appreciably change the VA value of biofortified maize.     

Identification of chlorophylls and carotenoids in major teas by high-performance liquid chromatography with photodiode array detection

The separation and identification of pigments, chlorophylls, and carotenoids of seven teas and fresh leaf of tea (Camellia sinensis) by high-performance liquid chromatography (HPLC) are described. HPLC was carried out using a Symmetry C(8) column with a photodiode array detector. Pigments were eluted with a binary gradient of aqueous pyridine solution at a flow rate of 1.0 mL/min at 25 degrees C. HPLC analyses achieved the separation of more than 100 pigment peaks, and 79 pigment species, 41 chlorophylls, and 38 carotenoids were detected. The presence of degraded chlorophylls was a common feature, and the number and the variety of pigments differed with tea species. Generally, the numbers of chlorophyll species tended to increase with processing steps, while carotenoid species were decreased, especially by heating. Particularly in green teas, a change of carotenoid structure, conversion of violaxanthin to auroxanthin, occurred. In hot water extracts of teas, both chlorophylls and carotenoids were also detected, but the concentration of chlorophylls was less than 2% as compared with acetone extracts. The pigment compositions were compared between tea species, and they are discussed in terms of the differences in their manufacturing processes.     

Evaluation of analytical methods for carotenoid extraction from biofortified maize (Zea mays sp.)

Biofortification of maize with beta-carotene has the potential to improve vitamin A status in vitamin A deficient populations where maize is a staple crop. Accurate assessment of provitamin A carotenoids in maize must be performed to direct breeding efforts. The objective was to evaluate carotenoid extraction methods and determine essential steps for use in countries growing biofortified maize. The most reproducible method based on coefficient of variation and extraction efficiency was a modification of Kurilich and Juvik (1999). Heat and saponification are required to release carotenoids from biofortified maize and remove oils interfering with chromatographic analysis. For maize samples with high oil content, additional base may be added to ensure complete saponification without compromising results. Degradation of internal standard before carotenoids were released from the maize matrix required the addition of internal standard after heating to prevent overestimation of carotenoids. This modified method works well for lutein, zeaxanthin, beta-cryptoxanthin, alpha-carotene, and beta-carotene.     

Association of carotenoids, tocopherols and vitamin C in plasma with allergic rhinitis and allergic sensitisation in adults

OBJECTIVES: Antioxidant nutrients like carotenoids, tocopherols and vitamin C have been suggested to protect against allergic rhinitis and allergic sensitisation but scientific evidence is scarce. The aims of the study were to measure the plasma concentration of six carotenoids, alpha- and gamma-tocopherol and vitamin C as biomarkers of the intake, absorption and subsequent metabolism of these nutrients, and to assess their association with allergic rhinitis and sensitisation. METHOD: Data from a cross-sectional study on representative dietary and lifestyle habits of the population of Bavaria, Germany, were analysed. The plasma levels of six carotenoids (alpha-carotene, beta-carotene, lycopene, lutein/zeaxanthin, canthaxanthin and cryptoxanthin) as well as of alpha-tocopherol, gamma-tocopherol and vitamin C were measured in 547 adults aged between 19 and 81 years. Participants with specific serum immunoglobulin E > or =700 U l(-1) were categorised as sensitised. The association of plasma antioxidant levels, allergic rhinitis and allergic sensitisation was assessed by means of unconditional logistic regression models. RESULTS: We observed a negative association between plasma total carotenoids and the prevalence of allergic rhinitis, with odds ratio (95% confidence interval) of 1.13 (0.54-2.39) for the second, 0.72 (0.33-1.58) for the third and 0.44 (0.19-1.03) for the fourth quartile of total carotenoids concentration (P for trend=0.0332); results for lycopene failed to reach statistical significance (P=0.0608). Other single carotenoids, tocopherols and vitamin C were unrelated to allergic rhinitis. Allergic sensitisation was negatively associated with plasma gamma-tocopherol, with odds ratio (95% confidence interval) of 0.92 (0.51-1.65) for the second, 1.00 (0.56-1.80) for the third and 0.45 (0.23-0.88) for the fourth quartile of plasma gamma-tocopherol concentration (P for trend=0.0410). No other antioxidant was significantly related to allergic sensitisation. CONCLUSIONS: High plasma carotenoid concentrations reflecting a diet high in various fruits and vegetables might have a protective effect on allergic rhinitis in adulthood.     

Comparison of the bioavailability of natural palm oil carotenoids and synthetic beta-carotene in humans

Palm oil carotenoids are a mixture of alpha- and beta-carotenes, which are used as food colorants. They may also be applied as a functional food ingredient because of the provitamin A activity of alpha- and beta-carotenes and their proposed beneficial roles in the prevention of chronic diseases. This paper discusses the results of an incomplete balanced crossover study with 69 healthy adult volunteers to compare palm oil carotenoids with synthetic beta-carotene in their efficacies to increase plasma levels of carotenoids. Four days of supplementation with natural palm oil carotenoids (7.6 mg/day of alpha-carotene, 11.9 mg/day of all-trans-beta-carotene, 7.5 mg/day of cis-beta-carotene) or synthetic beta-carotene (23.8 mg/day of all-trans-beta-carotene, 4.4 mg/day of cis-beta-carotene), added to a mixed meal, resulted in significant increases in plasma levels of the supplied carotenoids as compared to consumption of a low-carotenoid meal (i.e., 7.2-fold increase in alpha-carotene and 3.5-fold increase in all-trans-beta-carotene following palm oil carotenoids; 6.9-fold increase in all-trans beta-carotene following synthetic beta-carotene). As the carotenoid content differed between the treatments, the relative plasma responses were calculated per milligram of beta-carotene intake. These were similar for the two supplements, suggesting that the presence of alpha-carotene does not affect the bioavailability of beta-carotene from palm oil. It was concluded that 4 days of supplementation with palm oil carotenoids or synthetic beta-carotene improves the plasma beta-carotene status substantially, whereas alpha-carotene is additionally delivered by the palm oil supplement.     

Changes in volatile flavor components of guava juice with high-pressure treatment and heat processing and during storage.

The changes in volatile flavor components of guava juice during pressure processing (25 degrees C, 600 MPa, 15 min), heat processing (95 degrees C, 5 min), and storage at 4 and 25 degrees C were evaluated by purge and trap/gas chromatography/mass spectrometry. Esters were the major volatile fraction in guava juice, and alcohols were the second. Pressure processing could maintain the original flavor distribution of the juice. Heat processing (95 degrees C, 5 min) caused decreases in the majority of flavor components in the juice when compared with freshly extracted juice. High-pressure treatment at 600 MPa for 15 min can effectively sterilize microbes but partially inactivate enzymes of guava juice; therefore, volatile components in pressure-treated juice gradually changed during storage periods. Pressure-treated guava juice showed increases in methanol, ethanol, and 2-ethylfuran with decreases in the other components during storage period. Nevertheless, the volatile distribution of 600 MPa treated guava juice was similar to that of freshly extracted juice when stored at 4 degrees C for 30 days.     

Stable isotope dilution techniques for assessing vitamin A status and bioefficacy of provitamin A carotenoids in humans

Vitamin A deficiency is a major global public health problem. Among the variety of techniques that are available for assessing human vitamin A status, evaluating the provitamin A nutritional values of foodstuffs and estimating human vitamin A requirements, isotope dilution provides the most accurate estimates. Although the relative expense of isotope dilution restricts its applications, it has an important function as the standard of reference for other techniques. Mathematical modelling plays an indispensable role in the interpretation of isotope dilution data. This review summarises recent applications of stable isotope methodology to determine human vitamin A status, estimate human vitamin A requirements, and calculate the bioconversion and bioefficacy of food carotenoids.