In terms of public health, drinking fruit and vegetable juices may well be as effective as consum... more In terms of public health, drinking fruit and vegetable juices may well be as effective as consuming whole fruits and vegetables with regard to reducing the risk of chronic disorders. Many of their health benefits can be attributed to phenolic compounds. Phenolic compounds are aromatic metabolites of plants secondary metabolism that have a common structure with an aromatic ring with at least one hydroxyl group, which provides the ability to neutralize reactive species, helping the body to protect itself from oxidative stress. Phenols contribute to fruits' color and taste and have been described as possessing anticarcinogenic and antimutagenic activity. Furthermore, they have been shown to be good contributors to the total antioxidant capacity of foods, resulting in a beneficial effect to human health. Due to the growing popularity of phenolic antioxidant over the past two decades, an increasing interest in determining the antioxidant activities exhibited by phenolic compounds an...
Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Docume... more Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Barba, F.J.; Department of Nutrition and Food Chemistry, Universitat de Valencia, Avda. Vicent Andrés Estellés, s/n, 46100 Burjassot, Spain, References: Butz, P., Koller, W.D., Tauscher, B., Wolf, S., Ultra-high pressure processing of onions: Chemical and sensory changes (1994) Lebensmittel-Wissenschaft Und- Technologie, 27 (5), pp. 463-467;, Sponsors: Valorial l'Aliment de Demain; CNRS; PONAN - Pole Alimentation et Nutrition; INRA; Pays de la Loire; Nantes Metropole Communaute Urbaine
Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Docume... more Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Barba, F.J.; Departmemt of Nutrition and Food Chemistry, University of Valencia, Avda. Vicent Andrés Estellés, s/n, 46100 Burjassot, Spain, References: Adapa, S., Schmidt, K.A., Toledo, R., Functional properties of skim milk processed with continuous high pressure throttling (1997) Journal of Dairy Science, 80, pp. 1941-1948;, Sponsors: Valorial l'Aliment de Demain; CNRS; PONAN - Pole Alimentation et Nutrition; INRA; Pays de la Loire; Nantes Metropole Communaute Urbaine
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2002
The determination of diacetyl permits the detection of microbial growth in the processing of citr... more The determination of diacetyl permits the detection of microbial growth in the processing of citrus fruit before the appearance of other organoleptic, chemical or microbiological changes. It also makes it possible to detect a break in the cold chain during distribution and sale. The study proposed a polarographic method for the determination of diacetyl that allowed routine analysis with the
ABSTRACT The effects of high-pressure (HP) treatment (400 MPa at 42 °C for 5 min) and pulsed elec... more ABSTRACT The effects of high-pressure (HP) treatment (400 MPa at 42 °C for 5 min) and pulsed electric field (PEF) processing (25 kV/cm at 57 °C for 280 μs) on ascorbic acid, total carotenoids, total phenolic compounds and total antioxidant capacity (TEAC and ORAC) of an orange juice–milk (OJ-M) beverage along the storage time at 4 °C were compared with a conventional heat preservation technology used in industry (90 °C for 15 s). During storage, ascorbic acid, total carotenoids and antioxidant capacity (TEAC) depleted with time regardless of the treatment applied. Instead, total phenolic content and antioxidant capacity measured by the ORAC method increased at the end of the storage. Non-thermal-treated beverage had less non-enzymatic browning than the thermally pasteurized one. There were no significant variations in the hidroxymethylfurfural (HMF) content of the HP- and PEF-treated OJ-M, whilst a significant increase was obtained after thermal treatment. During refrigerated storage, HMF was always below the maximum values established. The HP treatments reduced the L* value of the treated beverages immediately after processing and during refrigerated storage and induced an increase in total colour differences of beverages treated by HP compared with PEF and thermally processed orange juice–milk. Hence, alternative methods such as HP and PEF may give new opportunities to develop orange juice–milk with an equivalent shelf life to that of thermally treated orange juice mixed with milk in terms of microbial, physicochemical and nutritional characteristics.
ABSTRACT The effect of different concentrations of Stevia rebaudiana Bertoni (Stevia) on polyphen... more ABSTRACT The effect of different concentrations of Stevia rebaudiana Bertoni (Stevia) on polyphenoloxidase and peroxidase activities, antioxidant capacity and other bioactive compounds of a mixture of fruits, during 10 days of incubation at 10 and 37 °C, was studied. A significant decrease (p < 0.05) in both enzyme activities was observed when Stevia was added, showing an inhibitory effect. Samples with a high Stevia concentration showed the highest total phenolic content and antioxidant capacity, whereas non-significant changes were found in the ascorbic acid and carotenoid contents of the samples with Stevia added. A negative significant dependence (p < 0.05) during incubation was obtained between enzyme activity and antioxidant capacity, so that antioxidant capacity increases as enzyme activity decreases. Therefore, enzyme activity could be used as an indirect index of antioxidant capacity. The results clearly showed that Stevia had significant potential for use not only as a sweetener but also as a natural preservative agent.
ABSTRACT Traditionally, plant-based products have been used for different purposes. From ancient ... more ABSTRACT Traditionally, plant-based products have been used for different purposes. From ancient times, people on all continents have long applied poultices and imbibed infusions of indigenous plants. Numerous reports regarding the use of leaf vegetable products for the treatment of many human diseases have been made. Proven medicinal properties include antioxidant, anti-inflammatory, antiallergic, antibacterial, and antiviral effects. Most of these properties can be attributed to its high content in bioactive compounds. Bioactive compounds are secondary metabolites of plants, which are extra nutritional constituents that typically occur in small quantities in foods. They are being intensively studied in order to evaluate their effects on health. These compounds may elicit a long range of different effects in man and animals eating the plants dependent on plant species and amount eaten. Plants with potent bioactive compounds are often characterized as both poisonous and medicinal, and their beneficial or adverse result may depend on the amount eaten and the context of intake. For typical food and feed plants with bioactive compounds with less pronounced effects, the intakes are usually regarded as beneficial. According to several studies, the great number of potentially beneficial compounds and their multifunctional properties makes plant products perfect candidates for the production of health-promoting food and food supplements. The aim of this chapter is to present a review in terms of leaf vegetable products as source of bioactive compounds, including its antioxidant and antimicrobial activities.
The aim of this study was to obtain a beverage with a high content of bioactive compounds. Theref... more The aim of this study was to obtain a beverage with a high content of bioactive compounds. Therefore, a mixture of orange juice and milk was prepared. The effect of high-pressure processing (HPP), four different pressures (100, 200, 300, and 400 MPa), four treatment times for each pressure (120, 300, 420, and 540 s) on antioxidant compounds, and quality parameters was studied.
The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscle... more The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscles (Longissimus dorsi, loin; Biceps femoris, ham; and Triceps brachii, shoulder) and in pork and other meat products (cooked, pickled, and cured), of importance because they are consumed in high quantities. The results were compared with values reported by other authors and their contribution to the daily intake of these vitamins estimated. This showed that pork provides, on average, 97, 25.8, 35/43.7 (men/women), and 37% of the RDA (Recommended Dietary Allowances) for vitamins B(1), B(2), B(6), and B(12), respectively.
The degradation of ascorbic acid was studied in mushrooms heated at temperatures between 110 and ... more The degradation of ascorbic acid was studied in mushrooms heated at temperatures between 110 and 140°C, high-temperature short-time conditions, in a five-channel computer-controlled thermoresistometer. The kinetics parameters were calculated on the assumption that there are 2 degradation mechanisms, one aerobic (during the first few seconds of the process) and the other anaerobic. The 2 stages followed first-order reaction kinetics, with
Seventeen commercially available, "ready to drink" fortified beverages consisti... more Seventeen commercially available, "ready to drink" fortified beverages consisting of mixtures of fruit juices and milk were analyzed to evaluate their carotenoid profile (including their Z/E stereoisomers) and color during their commercial shelf life. Lightness (L*) was found to be correlated with the content of milk in the mixtures (r= 0.649) whereas red-yellow colors were correlated with the contents of alpha-carotene, beta-cryptoxanthin, and beta-carotene supplied by the fruit. The beverages stored under refrigeration (4 +/- 2 degrees C) showed higher luminosity (L*) and higher saturation of color (C*) and yellowness (b*). Differences (P < 0.05) in the levels of carotenoids were found among the beverages. Common fruits such as apple, lemon, pear, strawberry, kiwifruit, pineapple, and banana were low in carotenoids. However, orange, apricot, mango, and peach contributed significantly (P < 0.05) to increasing beta-cryptoxanthin and beta-carotene concentrations. Passion fruit supplied zeta-carotene, and the presence of carrot increased the levels of alpha-carotene and beta-carotene. Conversion of all-Ebeta-carotene and beta-cryptoxanthin to their Z isomers took place in 8 of the 17 samples containing alpha-carotene and in 9 of the 13 samples containing beta-cryptoxanthin, respectively, which resulted in some loss of provitamin A activity and nutritional value.
ABSTRACT The effects of the physicochemical and quality characteristics of various refrigerated m... more ABSTRACT The effects of the physicochemical and quality characteristics of various refrigerated mixed orange and carrot juices, and their changes with storage time and temperature were investigated. Density, dry extract, Brix values, acidity, turbidity, formol index, pectinmethylesterase, hydroxymethylfurfural, essential oils, ascorbic acid, and color varied with storage time and temperature. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation of ascorbic acid corresponded to 1st-order kinetics. The shelf life of the juices was established at 4 °C and 50-d storage or at 10 °C and 32-d storage.
The degradation kinetics of ascorbic acid was determined in orangecarrot juice treated by PEF in... more The degradation kinetics of ascorbic acid was determined in orangecarrot juice treated by PEF in order to establish its shelf life. Different electric field intensities (25, 30, 35, and 40 kV/cm) and different treatment times (from 30 to 340 μs) were studied. The ascorbic acid degradation ...
A liquid chromatographic method for determining vitamin B6 compounds in pork meat and pork meat p... more A liquid chromatographic method for determining vitamin B6 compounds in pork meat and pork meat products is examined. It uses the same extraction procedure as that applied for thiamin and riboflavin determination, followed by a liquid chromatographic separation on a reversed-phase C18 column with 0.01 M H2SO4 as mobile phase at 30 degrees C. 4-Deoxypyridoxine is used as internal standard. The analytical parameters linearity, precision of the method (R.S.D. = 7.3 and 6.9% for pyridoxamine and pyridoxal, respectively) and accuracy obtained by recovery assays (99 and 85.1% for pyridoxamine and pyridoxal, respectively) show that the studied method is useful to measure these compounds in pork meat.
A method for the simultaneous determination of liposoluble vitamins in cooked meals was establish... more A method for the simultaneous determination of liposoluble vitamins in cooked meals was established. Saponification was performed with 50% (w/v) KOH at 80 degrees C, and ascorbic acid was added as antioxidant. The subsequent extraction was carried out with diethyl ether. This was followed by a liquid chromatographic separation on a reversed-phase C18 column with methanol-water (94:6, v/v as the mobile phase. Retinyl acetate was used as the internal standard. The analytical parameters linearity, detection limit (0.19 and 8.33 microg/100 g for retinol and alpha-tocopherol, respectively), precision of the method (RSD=5.24 and 6.99% for retinol and alpha-tocopherol, respectively) and recovery assays (95.6 and 96.5% for retinol and alpha-tocopherol, respectively) show that the method studied is useful for measuring these compounds in foods and cooked meals.
Journal of agricultural and food chemistry, Jan 22, 2010
Variations in levels of antioxidant compounds (ascorbic acid, total phenolics, and total caroteno... more Variations in levels of antioxidant compounds (ascorbic acid, total phenolics, and total carotenoids), total antioxidant capacity, and color changes in a vegetable (tomato, green pepper, green celery, onion, carrot, lemon, and olive oil) beverage treated by high hydrostatic pressure (HHP) were evaluated in this work. The effects of HHP treatment, four different pressures (100, 200, 300, and 400 MPa) and four treatment times for each pressure (from 120 to 540 s) were compared with those of thermal treatment (90-98 °C for 15 and 21 s). High pressure treatment retained significantly more ascorbic acid in the vegetable beverage than thermal treatment. However, no significant changes in total phenolics were observed between HHP treated and thermally processed vegetable beverage and unprocessed beverage. Color changes (a*, b*, L, chroma, h°, and ΔE) were less for pressurized beverage than thermally treated samples compared with unprocessed beverage.
A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determinati... more A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and riboflavin, respectively), and the results of the comparison with the corresponding AOAC fluorometric methods show that the studied method is useful for the measurement of thiamin and riboflavin in fresh mushrooms.
In terms of public health, drinking fruit and vegetable juices may well be as effective as consum... more In terms of public health, drinking fruit and vegetable juices may well be as effective as consuming whole fruits and vegetables with regard to reducing the risk of chronic disorders. Many of their health benefits can be attributed to phenolic compounds. Phenolic compounds are aromatic metabolites of plants secondary metabolism that have a common structure with an aromatic ring with at least one hydroxyl group, which provides the ability to neutralize reactive species, helping the body to protect itself from oxidative stress. Phenols contribute to fruits' color and taste and have been described as possessing anticarcinogenic and antimutagenic activity. Furthermore, they have been shown to be good contributors to the total antioxidant capacity of foods, resulting in a beneficial effect to human health. Due to the growing popularity of phenolic antioxidant over the past two decades, an increasing interest in determining the antioxidant activities exhibited by phenolic compounds an...
Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Docume... more Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Barba, F.J.; Department of Nutrition and Food Chemistry, Universitat de Valencia, Avda. Vicent Andrés Estellés, s/n, 46100 Burjassot, Spain, References: Butz, P., Koller, W.D., Tauscher, B., Wolf, S., Ultra-high pressure processing of onions: Chemical and sensory changes (1994) Lebensmittel-Wissenschaft Und- Technologie, 27 (5), pp. 463-467;, Sponsors: Valorial l'Aliment de Demain; CNRS; PONAN - Pole Alimentation et Nutrition; INRA; Pays de la Loire; Nantes Metropole Communaute Urbaine
Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Docume... more Conference code: 89672, Export Date: 23 January 2013, Source: Scopus, Language of Original Document: English, Correspondence Address: Barba, F.J.; Departmemt of Nutrition and Food Chemistry, University of Valencia, Avda. Vicent Andrés Estellés, s/n, 46100 Burjassot, Spain, References: Adapa, S., Schmidt, K.A., Toledo, R., Functional properties of skim milk processed with continuous high pressure throttling (1997) Journal of Dairy Science, 80, pp. 1941-1948;, Sponsors: Valorial l'Aliment de Demain; CNRS; PONAN - Pole Alimentation et Nutrition; INRA; Pays de la Loire; Nantes Metropole Communaute Urbaine
Food Additives and Contaminants Part A-chemistry Analysis Control Exposure & Risk Assessment, 2002
The determination of diacetyl permits the detection of microbial growth in the processing of citr... more The determination of diacetyl permits the detection of microbial growth in the processing of citrus fruit before the appearance of other organoleptic, chemical or microbiological changes. It also makes it possible to detect a break in the cold chain during distribution and sale. The study proposed a polarographic method for the determination of diacetyl that allowed routine analysis with the
ABSTRACT The effects of high-pressure (HP) treatment (400 MPa at 42 °C for 5 min) and pulsed elec... more ABSTRACT The effects of high-pressure (HP) treatment (400 MPa at 42 °C for 5 min) and pulsed electric field (PEF) processing (25 kV/cm at 57 °C for 280 μs) on ascorbic acid, total carotenoids, total phenolic compounds and total antioxidant capacity (TEAC and ORAC) of an orange juice–milk (OJ-M) beverage along the storage time at 4 °C were compared with a conventional heat preservation technology used in industry (90 °C for 15 s). During storage, ascorbic acid, total carotenoids and antioxidant capacity (TEAC) depleted with time regardless of the treatment applied. Instead, total phenolic content and antioxidant capacity measured by the ORAC method increased at the end of the storage. Non-thermal-treated beverage had less non-enzymatic browning than the thermally pasteurized one. There were no significant variations in the hidroxymethylfurfural (HMF) content of the HP- and PEF-treated OJ-M, whilst a significant increase was obtained after thermal treatment. During refrigerated storage, HMF was always below the maximum values established. The HP treatments reduced the L* value of the treated beverages immediately after processing and during refrigerated storage and induced an increase in total colour differences of beverages treated by HP compared with PEF and thermally processed orange juice–milk. Hence, alternative methods such as HP and PEF may give new opportunities to develop orange juice–milk with an equivalent shelf life to that of thermally treated orange juice mixed with milk in terms of microbial, physicochemical and nutritional characteristics.
ABSTRACT The effect of different concentrations of Stevia rebaudiana Bertoni (Stevia) on polyphen... more ABSTRACT The effect of different concentrations of Stevia rebaudiana Bertoni (Stevia) on polyphenoloxidase and peroxidase activities, antioxidant capacity and other bioactive compounds of a mixture of fruits, during 10 days of incubation at 10 and 37 °C, was studied. A significant decrease (p < 0.05) in both enzyme activities was observed when Stevia was added, showing an inhibitory effect. Samples with a high Stevia concentration showed the highest total phenolic content and antioxidant capacity, whereas non-significant changes were found in the ascorbic acid and carotenoid contents of the samples with Stevia added. A negative significant dependence (p < 0.05) during incubation was obtained between enzyme activity and antioxidant capacity, so that antioxidant capacity increases as enzyme activity decreases. Therefore, enzyme activity could be used as an indirect index of antioxidant capacity. The results clearly showed that Stevia had significant potential for use not only as a sweetener but also as a natural preservative agent.
ABSTRACT Traditionally, plant-based products have been used for different purposes. From ancient ... more ABSTRACT Traditionally, plant-based products have been used for different purposes. From ancient times, people on all continents have long applied poultices and imbibed infusions of indigenous plants. Numerous reports regarding the use of leaf vegetable products for the treatment of many human diseases have been made. Proven medicinal properties include antioxidant, anti-inflammatory, antiallergic, antibacterial, and antiviral effects. Most of these properties can be attributed to its high content in bioactive compounds. Bioactive compounds are secondary metabolites of plants, which are extra nutritional constituents that typically occur in small quantities in foods. They are being intensively studied in order to evaluate their effects on health. These compounds may elicit a long range of different effects in man and animals eating the plants dependent on plant species and amount eaten. Plants with potent bioactive compounds are often characterized as both poisonous and medicinal, and their beneficial or adverse result may depend on the amount eaten and the context of intake. For typical food and feed plants with bioactive compounds with less pronounced effects, the intakes are usually regarded as beneficial. According to several studies, the great number of potentially beneficial compounds and their multifunctional properties makes plant products perfect candidates for the production of health-promoting food and food supplements. The aim of this chapter is to present a review in terms of leaf vegetable products as source of bioactive compounds, including its antioxidant and antimicrobial activities.
The aim of this study was to obtain a beverage with a high content of bioactive compounds. Theref... more The aim of this study was to obtain a beverage with a high content of bioactive compounds. Therefore, a mixture of orange juice and milk was prepared. The effect of high-pressure processing (HPP), four different pressures (100, 200, 300, and 400 MPa), four treatment times for each pressure (120, 300, 420, and 540 s) on antioxidant compounds, and quality parameters was studied.
The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscle... more The concentration of B vitamins (B(1), B(2), B(6), and B(12)) was determined in three pork muscles (Longissimus dorsi, loin; Biceps femoris, ham; and Triceps brachii, shoulder) and in pork and other meat products (cooked, pickled, and cured), of importance because they are consumed in high quantities. The results were compared with values reported by other authors and their contribution to the daily intake of these vitamins estimated. This showed that pork provides, on average, 97, 25.8, 35/43.7 (men/women), and 37% of the RDA (Recommended Dietary Allowances) for vitamins B(1), B(2), B(6), and B(12), respectively.
The degradation of ascorbic acid was studied in mushrooms heated at temperatures between 110 and ... more The degradation of ascorbic acid was studied in mushrooms heated at temperatures between 110 and 140°C, high-temperature short-time conditions, in a five-channel computer-controlled thermoresistometer. The kinetics parameters were calculated on the assumption that there are 2 degradation mechanisms, one aerobic (during the first few seconds of the process) and the other anaerobic. The 2 stages followed first-order reaction kinetics, with
Seventeen commercially available, "ready to drink" fortified beverages consisti... more Seventeen commercially available, "ready to drink" fortified beverages consisting of mixtures of fruit juices and milk were analyzed to evaluate their carotenoid profile (including their Z/E stereoisomers) and color during their commercial shelf life. Lightness (L*) was found to be correlated with the content of milk in the mixtures (r= 0.649) whereas red-yellow colors were correlated with the contents of alpha-carotene, beta-cryptoxanthin, and beta-carotene supplied by the fruit. The beverages stored under refrigeration (4 +/- 2 degrees C) showed higher luminosity (L*) and higher saturation of color (C*) and yellowness (b*). Differences (P < 0.05) in the levels of carotenoids were found among the beverages. Common fruits such as apple, lemon, pear, strawberry, kiwifruit, pineapple, and banana were low in carotenoids. However, orange, apricot, mango, and peach contributed significantly (P < 0.05) to increasing beta-cryptoxanthin and beta-carotene concentrations. Passion fruit supplied zeta-carotene, and the presence of carrot increased the levels of alpha-carotene and beta-carotene. Conversion of all-Ebeta-carotene and beta-cryptoxanthin to their Z isomers took place in 8 of the 17 samples containing alpha-carotene and in 9 of the 13 samples containing beta-cryptoxanthin, respectively, which resulted in some loss of provitamin A activity and nutritional value.
ABSTRACT The effects of the physicochemical and quality characteristics of various refrigerated m... more ABSTRACT The effects of the physicochemical and quality characteristics of various refrigerated mixed orange and carrot juices, and their changes with storage time and temperature were investigated. Density, dry extract, Brix values, acidity, turbidity, formol index, pectinmethylesterase, hydroxymethylfurfural, essential oils, ascorbic acid, and color varied with storage time and temperature. Some of the parameters could be used as indicators of quality loss or spoilage of the juices. The degradation of ascorbic acid corresponded to 1st-order kinetics. The shelf life of the juices was established at 4 °C and 50-d storage or at 10 °C and 32-d storage.
The degradation kinetics of ascorbic acid was determined in orangecarrot juice treated by PEF in... more The degradation kinetics of ascorbic acid was determined in orangecarrot juice treated by PEF in order to establish its shelf life. Different electric field intensities (25, 30, 35, and 40 kV/cm) and different treatment times (from 30 to 340 μs) were studied. The ascorbic acid degradation ...
A liquid chromatographic method for determining vitamin B6 compounds in pork meat and pork meat p... more A liquid chromatographic method for determining vitamin B6 compounds in pork meat and pork meat products is examined. It uses the same extraction procedure as that applied for thiamin and riboflavin determination, followed by a liquid chromatographic separation on a reversed-phase C18 column with 0.01 M H2SO4 as mobile phase at 30 degrees C. 4-Deoxypyridoxine is used as internal standard. The analytical parameters linearity, precision of the method (R.S.D. = 7.3 and 6.9% for pyridoxamine and pyridoxal, respectively) and accuracy obtained by recovery assays (99 and 85.1% for pyridoxamine and pyridoxal, respectively) show that the studied method is useful to measure these compounds in pork meat.
A method for the simultaneous determination of liposoluble vitamins in cooked meals was establish... more A method for the simultaneous determination of liposoluble vitamins in cooked meals was established. Saponification was performed with 50% (w/v) KOH at 80 degrees C, and ascorbic acid was added as antioxidant. The subsequent extraction was carried out with diethyl ether. This was followed by a liquid chromatographic separation on a reversed-phase C18 column with methanol-water (94:6, v/v as the mobile phase. Retinyl acetate was used as the internal standard. The analytical parameters linearity, detection limit (0.19 and 8.33 microg/100 g for retinol and alpha-tocopherol, respectively), precision of the method (RSD=5.24 and 6.99% for retinol and alpha-tocopherol, respectively) and recovery assays (95.6 and 96.5% for retinol and alpha-tocopherol, respectively) show that the method studied is useful for measuring these compounds in foods and cooked meals.
Journal of agricultural and food chemistry, Jan 22, 2010
Variations in levels of antioxidant compounds (ascorbic acid, total phenolics, and total caroteno... more Variations in levels of antioxidant compounds (ascorbic acid, total phenolics, and total carotenoids), total antioxidant capacity, and color changes in a vegetable (tomato, green pepper, green celery, onion, carrot, lemon, and olive oil) beverage treated by high hydrostatic pressure (HHP) were evaluated in this work. The effects of HHP treatment, four different pressures (100, 200, 300, and 400 MPa) and four treatment times for each pressure (from 120 to 540 s) were compared with those of thermal treatment (90-98 °C for 15 and 21 s). High pressure treatment retained significantly more ascorbic acid in the vegetable beverage than thermal treatment. However, no significant changes in total phenolics were observed between HHP treated and thermally processed vegetable beverage and unprocessed beverage. Color changes (a*, b*, L, chroma, h°, and ΔE) were less for pressurized beverage than thermally treated samples compared with unprocessed beverage.
A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determinati... more A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and riboflavin, respectively), and the results of the comparison with the corresponding AOAC fluorometric methods show that the studied method is useful for the measurement of thiamin and riboflavin in fresh mushrooms.
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