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Miroslav Strnad - One of the best experts on this subject based on the ideXlab platform.
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Phenolic acid content and radical scavenging activity of extracts from medlar (Mespilus germanica L.) fruit at different stages of ripening
Food Chemistry, 2011Co-Authors: Jiri Gruz, Faik Ahmet Ayaz, Hülya Torun, Miroslav StrnadAbstract:Abstract The medlar fruit (Mespilus germanica L.) has been gaining commercial importance in recent years, attracting research on its chemical composition. In this study, we have investigated how the degree of ripeness affects the concentrations and proportions of phenolic acids. The DPPH scavenging activity and the total phenolic content (TPC) were determined. Five stages of fruit maturity were studied and eight phenolic acids (protocatechuic, 4-hydroxybenzoic, syringic, 3-hydroxybenzoic, caffeic, salicylic, 4-coumaric and sinapic) were determined by HPLC–MS. The concentrations of phenolic acids mostly decreased as the fruit ripening progressed, except for insoluble ester-bound phenolics, which increased at the early stages of maturity and decreased only during the ripe to over-ripe stage of maturity. The DPPH scavenging activity also decreased during fruit maturation, suggesting a decrease of natural antioxidants in fruit. A strong correlation between TPC and antioxidant capacity measured by the DPPH method was found. The data presented demonstrates the influence of ripening on the phenolic acid content and antioxidant properties of medlar fruit.
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changes in sugars organic acids and amino acids in medlar Mespilus germanica l during fruit development and maturation
Food Chemistry, 2003Co-Authors: Richard H. Glew, Faik Ahmet Ayaz, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, Miroslav StrnadAbstract:Abstract The contents of sugars, organic acids, and amino acids (after acid hydrolysis) were determined during development and maturation of medlar ( Mespilus germanica L.) fruit from 39 days after full bloom (DAF) until 2 weeks after the beginning of fruit drop (161 DAF). Fructose, glucose and sucrose were identified as the principal sugars and their levels varied remarkably during development. The fructose level increased continually through development reaching its maximum by 161 DAF (1200 mg/100 g fresh weight) while the increase of sucrose reached maximum at 131 DAF and had decreased at 161 DAF. After some fluctations at 69 DAF, glucose level remained high (686 mg/100 g fresh weight) at 161 DAF, when compared with Stage IV (131 DAF). While the level of malic acid increased continually, the ascorbic acid level decreased dramatically through fruit development; both acids reached their maximum and minimum levels at 161 DAF, i.e. 428 and 8.4 mg/100 g fresh weight, respectively. The total amino acid composition also changed in decreasing trend throughout development and remained low at 161 DAF. In the ripe fruit, glutamate and aspartate were the major amino compounds identified. These changes in the identified compounds can be related to the metabolic activity during fruit development and maturation.
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Effect of postharvest period on sugars, organic acids and fatty acids composition in commercially sold medlar ( Mespilus germanica 'Dutch') fruit
European Food Research and Technology, 2003Co-Authors: Richard H. Glew, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, F. Ahmet Ayaz, Miroslav StrnadAbstract:Fructose, glucose, and sucrose as the major soluble sugars, and citric, malic, and ascorbic acids as the major organic acids were determined by HPLC, and palmitic acid (16:0) and stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) as the major fatty acids were determined by GC in medlar (Mespilus germanica 'Dutch') fruit. The compositional changes of these constituents were monitored during the post harvest period of commercially sold Dutch form throughout its rapid ripening (fruit softening-darkening). Sucrose was highest at 1 WAH (228.4 mg/100 g fresh wt) and then decreased, remaining very low at 4 WAH (1.4 mg/100 g fresh wt). As for the levels of fructose and glucose, their levels shifted up to 2230.8 and 845.2 mg/100 g fresh wt at 2 and 3 WAHs, then the levels lessened to their lowest concentration. The levels of the three acids were high at the beginning, except malic acid level at 2 WAH, all acids leveled off through the latter weeks of post harvest period. In the fruit studied, the levels of saturated palmitic acid (16:0) and stearic acid (18:0), and unsaturated oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) were most abundant fatty acids detected throughout medlar ripening (pulp softening and darkening). The level of palmitic and stearic acids as well as the level of linoleic and linolenic acids were the highest at 1 WAH and then suddenly decreased as the medlar soften and the pulp becomes slightly (2 WAH) and fully (3 WAH) brown through 2 and 4 WAHs. In addition to these prominent fatty acids, a remarkable decrease was also obtained in the content of some other fatty acids (C10–15, C16:1, C20–24).
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Evolution of fatty acids in medlar (Mespilus germanica L.) mesocarp at different stages of ripening
Grasas y Aceites, 2002Co-Authors: Faik Ahmet Ayaz, L T Chuang, H.s. Huang, Dorothy J Vanderjagt, R.h. Glew, Miroslav StrnadAbstract:The fatty acid composition of medlar ( Mespilus germanica L. ) varied significantly among the ripening stages sampled at 157, 172 and 187 DAFs (days after full bloom). Twenty-one different fatty acids were detected in preclimacteric fruit and 17 when the climacteric began. Principal fatty acids, determined in medlar fruit harvested from October (157 and 172 DAFs) to November (187 DAF) were mainly palmitic acid (16:0), linoleic acid (18:2n-6), and a-linolenic acid (18:3n-3). While the content of saturated fatty acids [palmitic acid (16:0) and stearic acid (18:0)] increased, the content of the essential polyunsaturated fatty acids [linoleic acid (18:2n-6) and linolenic acid (18:3n-3)] decreased through ripening, in parallel with pulp darkening. The percentage of linoleic acid and a-linolenic acid in ripe, hard fruits was 60.0 and 13.5 % of dry wt at 157 DAF which decreased throughout ripening, remaining at 28.7 and 5.6 % of dry wt, respectively, in the fully softened and darkened pulp. A marked decreases in the double bond index, percentage of unsaturation and the ratio of unsaturation/saturation were also seen throughout the medlar ripening. The contribution of unsaturated fatty acid to the total fatty acid content decreased markedly as the medlar fruit became progressively softer and darkened.
Faik Ahmet Ayaz - One of the best experts on this subject based on the ideXlab platform.
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Phenolic acid content and radical scavenging activity of extracts from medlar (Mespilus germanica L.) fruit at different stages of ripening
Food Chemistry, 2011Co-Authors: Jiri Gruz, Faik Ahmet Ayaz, Hülya Torun, Miroslav StrnadAbstract:Abstract The medlar fruit (Mespilus germanica L.) has been gaining commercial importance in recent years, attracting research on its chemical composition. In this study, we have investigated how the degree of ripeness affects the concentrations and proportions of phenolic acids. The DPPH scavenging activity and the total phenolic content (TPC) were determined. Five stages of fruit maturity were studied and eight phenolic acids (protocatechuic, 4-hydroxybenzoic, syringic, 3-hydroxybenzoic, caffeic, salicylic, 4-coumaric and sinapic) were determined by HPLC–MS. The concentrations of phenolic acids mostly decreased as the fruit ripening progressed, except for insoluble ester-bound phenolics, which increased at the early stages of maturity and decreased only during the ripe to over-ripe stage of maturity. The DPPH scavenging activity also decreased during fruit maturation, suggesting a decrease of natural antioxidants in fruit. A strong correlation between TPC and antioxidant capacity measured by the DPPH method was found. The data presented demonstrates the influence of ripening on the phenolic acid content and antioxidant properties of medlar fruit.
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Characterization of polyphenoloxidase (PPO) and total phenolic contents in medlar (Mespilus germanica L.) fruit during ripening and over ripening
Food Chemistry, 2008Co-Authors: Faik Ahmet Ayaz, Hülya Torun, O. Demir, Yakup Kolcuoğlu, Ahmet ColakAbstract:Abstract Characterization of polyphenoloxidase (PPO) enzyme and determination of total phenolic concentrations during fruit ripening and over ripening in medlar ( Mespilus germanica L.) were determined. During ripening, PPO substrate specificity, optimum pH and temperature, optimum enzyme and substrate concentrations were determined. Among the five mono- and di-phenolic substrates examined (( p -hydroxyphenyl) propionic acid, l -3,4-dihydroxyphenylalanine, catechol, 4-methylcatechol and tyrosine), 4-methylcatechol was selected as the best substrate for all ripening stages. A range of pH 3.0–9.0 was also tested and the highest enzyme activity was at pH 7.0 throughout ripening. The optimum temperature for each ripening stage was determined by measuring the enzyme activity at various temperatures over the range of 10–70 °C with 10 °C increments. The optimum temperatures were found to be 30, 20 and 30 °C, respectively, for each ripening stage. Optimum enzyme and substrate concentrations were found to be 0.1 mg/ml and 40 mM, respectively. The V max and K m value of the reaction were determined during ripening and found to be 476 U/mg protein and 26 mM at 193 DAFB (days after full bloom) – stage 1, 256 U/mg protein and 12 mM at 207 DAFB – stage 2, 222 U/mg protein and 8 mM at 214 DAFB – stage 3. For all ripening stages sodium metabisulfite markedly inhibited PPO activity. For stage 1 of ripening, Cu 2+ , Hg 2+ and Al 3+ , for stage 2, Cu 2+ and Hg 2+ , and for stage 3, Cu 2+ , Hg 2+ , Al 3+ and Ca 2+ strongly inhibited diphenolase activity. Accordingly, it can be concluded that as medlar fruit ripen there is no significant changes in the optimum values of polyphenoloxidases, although their kinetic parametres change. As the fruit ripening progressed through ripe to over-ripe, in contrary to polyphenoloxidase activity, there was an apparent gradual decrease in total fruit phenolic concentrations, as determined by using the aqueous solvents and water extractions.
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changes in sugars organic acids and amino acids in medlar Mespilus germanica l during fruit development and maturation
Food Chemistry, 2003Co-Authors: Richard H. Glew, Faik Ahmet Ayaz, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, Miroslav StrnadAbstract:Abstract The contents of sugars, organic acids, and amino acids (after acid hydrolysis) were determined during development and maturation of medlar ( Mespilus germanica L.) fruit from 39 days after full bloom (DAF) until 2 weeks after the beginning of fruit drop (161 DAF). Fructose, glucose and sucrose were identified as the principal sugars and their levels varied remarkably during development. The fructose level increased continually through development reaching its maximum by 161 DAF (1200 mg/100 g fresh weight) while the increase of sucrose reached maximum at 131 DAF and had decreased at 161 DAF. After some fluctations at 69 DAF, glucose level remained high (686 mg/100 g fresh weight) at 161 DAF, when compared with Stage IV (131 DAF). While the level of malic acid increased continually, the ascorbic acid level decreased dramatically through fruit development; both acids reached their maximum and minimum levels at 161 DAF, i.e. 428 and 8.4 mg/100 g fresh weight, respectively. The total amino acid composition also changed in decreasing trend throughout development and remained low at 161 DAF. In the ripe fruit, glutamate and aspartate were the major amino compounds identified. These changes in the identified compounds can be related to the metabolic activity during fruit development and maturation.
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Evolution of fatty acids in medlar (Mespilus germanica L.) mesocarp at different stages of ripening
Grasas y Aceites, 2002Co-Authors: Faik Ahmet Ayaz, L T Chuang, H.s. Huang, Dorothy J Vanderjagt, R.h. Glew, Miroslav StrnadAbstract:The fatty acid composition of medlar ( Mespilus germanica L. ) varied significantly among the ripening stages sampled at 157, 172 and 187 DAFs (days after full bloom). Twenty-one different fatty acids were detected in preclimacteric fruit and 17 when the climacteric began. Principal fatty acids, determined in medlar fruit harvested from October (157 and 172 DAFs) to November (187 DAF) were mainly palmitic acid (16:0), linoleic acid (18:2n-6), and a-linolenic acid (18:3n-3). While the content of saturated fatty acids [palmitic acid (16:0) and stearic acid (18:0)] increased, the content of the essential polyunsaturated fatty acids [linoleic acid (18:2n-6) and linolenic acid (18:3n-3)] decreased through ripening, in parallel with pulp darkening. The percentage of linoleic acid and a-linolenic acid in ripe, hard fruits was 60.0 and 13.5 % of dry wt at 157 DAF which decreased throughout ripening, remaining at 28.7 and 5.6 % of dry wt, respectively, in the fully softened and darkened pulp. A marked decreases in the double bond index, percentage of unsaturation and the ratio of unsaturation/saturation were also seen throughout the medlar ripening. The contribution of unsaturated fatty acid to the total fatty acid content decreased markedly as the medlar fruit became progressively softer and darkened.
Richard H. Glew - One of the best experts on this subject based on the ideXlab platform.
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changes in sugars organic acids and amino acids in medlar Mespilus germanica l during fruit development and maturation
Food Chemistry, 2003Co-Authors: Richard H. Glew, Faik Ahmet Ayaz, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, Miroslav StrnadAbstract:Abstract The contents of sugars, organic acids, and amino acids (after acid hydrolysis) were determined during development and maturation of medlar ( Mespilus germanica L.) fruit from 39 days after full bloom (DAF) until 2 weeks after the beginning of fruit drop (161 DAF). Fructose, glucose and sucrose were identified as the principal sugars and their levels varied remarkably during development. The fructose level increased continually through development reaching its maximum by 161 DAF (1200 mg/100 g fresh weight) while the increase of sucrose reached maximum at 131 DAF and had decreased at 161 DAF. After some fluctations at 69 DAF, glucose level remained high (686 mg/100 g fresh weight) at 161 DAF, when compared with Stage IV (131 DAF). While the level of malic acid increased continually, the ascorbic acid level decreased dramatically through fruit development; both acids reached their maximum and minimum levels at 161 DAF, i.e. 428 and 8.4 mg/100 g fresh weight, respectively. The total amino acid composition also changed in decreasing trend throughout development and remained low at 161 DAF. In the ripe fruit, glutamate and aspartate were the major amino compounds identified. These changes in the identified compounds can be related to the metabolic activity during fruit development and maturation.
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Effect of postharvest period on sugars, organic acids and fatty acids composition in commercially sold medlar ( Mespilus germanica 'Dutch') fruit
European Food Research and Technology, 2003Co-Authors: Richard H. Glew, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, F. Ahmet Ayaz, Miroslav StrnadAbstract:Fructose, glucose, and sucrose as the major soluble sugars, and citric, malic, and ascorbic acids as the major organic acids were determined by HPLC, and palmitic acid (16:0) and stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) as the major fatty acids were determined by GC in medlar (Mespilus germanica 'Dutch') fruit. The compositional changes of these constituents were monitored during the post harvest period of commercially sold Dutch form throughout its rapid ripening (fruit softening-darkening). Sucrose was highest at 1 WAH (228.4 mg/100 g fresh wt) and then decreased, remaining very low at 4 WAH (1.4 mg/100 g fresh wt). As for the levels of fructose and glucose, their levels shifted up to 2230.8 and 845.2 mg/100 g fresh wt at 2 and 3 WAHs, then the levels lessened to their lowest concentration. The levels of the three acids were high at the beginning, except malic acid level at 2 WAH, all acids leveled off through the latter weeks of post harvest period. In the fruit studied, the levels of saturated palmitic acid (16:0) and stearic acid (18:0), and unsaturated oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) were most abundant fatty acids detected throughout medlar ripening (pulp softening and darkening). The level of palmitic and stearic acids as well as the level of linoleic and linolenic acids were the highest at 1 WAH and then suddenly decreased as the medlar soften and the pulp becomes slightly (2 WAH) and fully (3 WAH) brown through 2 and 4 WAHs. In addition to these prominent fatty acids, a remarkable decrease was also obtained in the content of some other fatty acids (C10–15, C16:1, C20–24).
Osman Özbek - One of the best experts on this subject based on the ideXlab platform.
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Some physical and chemical parameters of wild medlar (Mespilus germanica L.) fruit grown in Turkey
Journal of Food Engineering, 2005Co-Authors: Haydar Hacıseferogˇulları, Musa Özcan, Mehmet Hakan Sonmete, Osman ÖzbekAbstract:Abstract Physical and chemical parameters of medlar fruit are necessary for the design of equipment to handle, harvest, process, store the product and nutrition values. In this study, the medlar ( Mespilus germanica L.) fruit was studied to determine for some physical (dimension, geometric mean diameter, sphericity, bulk density, fruit density, volume, hardness and porosity) and chemical (moisture, crude protein, oil, energy, fibre and ash, pH, acidity, water-soluble extract, alcohol-soluble extract and ether-soluble extracts) properties. Moisture, crude oil, protein, fibre, energy, and ash, acidity, pH, water-soluble extract, alcohol-soluble and ether-soluble were found to be 72.15%, 4.09%, 3.71%, 11.4%, 16.5 kcal/g, 1.96%, 0.28%, 4.26, 68.89%, 53.35% and 2.41% (dry basis (except for pH)), respectively. Inductively coupled plasma atomic emission spectrometer (ICP-AES) determined the mineral content of medlar fruit. Potassium (8052.91 mg/kg) was present in the highest concentration, following S, Ca, B and P. Also, K, S, Ca, B and S were present in higher concentrations, and traces of Cr, Ti and V were also determined. The fruit mass, diameter, volume, geometric mean diameter, sphericity and projected area were measured as 11.98 g, 27.68 mm, 13.68 cm 3 , 28.86 mm, 0.92, and 9.25 cm 2 , respectively. The changes in physical and chemical properties of fruits having about the same size were probably due to environmental conditions in conjunction with the analytical methods used. Consequently, the analytical values showed rich nutritional properties and mineral contents of medlar fruits. Also, the mineral content of medlar fruit is of great interest. In addition, knowledge of the physical properties of equipment used in planting, harvesting, transportation, storage and processing of matured medlar fruits is very important.
Carlos Sanz - One of the best experts on this subject based on the ideXlab platform.
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changes in sugars organic acids and amino acids in medlar Mespilus germanica l during fruit development and maturation
Food Chemistry, 2003Co-Authors: Richard H. Glew, Faik Ahmet Ayaz, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, Miroslav StrnadAbstract:Abstract The contents of sugars, organic acids, and amino acids (after acid hydrolysis) were determined during development and maturation of medlar ( Mespilus germanica L.) fruit from 39 days after full bloom (DAF) until 2 weeks after the beginning of fruit drop (161 DAF). Fructose, glucose and sucrose were identified as the principal sugars and their levels varied remarkably during development. The fructose level increased continually through development reaching its maximum by 161 DAF (1200 mg/100 g fresh weight) while the increase of sucrose reached maximum at 131 DAF and had decreased at 161 DAF. After some fluctations at 69 DAF, glucose level remained high (686 mg/100 g fresh weight) at 161 DAF, when compared with Stage IV (131 DAF). While the level of malic acid increased continually, the ascorbic acid level decreased dramatically through fruit development; both acids reached their maximum and minimum levels at 161 DAF, i.e. 428 and 8.4 mg/100 g fresh weight, respectively. The total amino acid composition also changed in decreasing trend throughout development and remained low at 161 DAF. In the ripe fruit, glutamate and aspartate were the major amino compounds identified. These changes in the identified compounds can be related to the metabolic activity during fruit development and maturation.
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Effect of postharvest period on sugars, organic acids and fatty acids composition in commercially sold medlar ( Mespilus germanica 'Dutch') fruit
European Food Research and Technology, 2003Co-Authors: Richard H. Glew, L T Chuang, Carlos Sanz, H.s. Huang, Dorothy J Vanderjagt, F. Ahmet Ayaz, Miroslav StrnadAbstract:Fructose, glucose, and sucrose as the major soluble sugars, and citric, malic, and ascorbic acids as the major organic acids were determined by HPLC, and palmitic acid (16:0) and stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) as the major fatty acids were determined by GC in medlar (Mespilus germanica 'Dutch') fruit. The compositional changes of these constituents were monitored during the post harvest period of commercially sold Dutch form throughout its rapid ripening (fruit softening-darkening). Sucrose was highest at 1 WAH (228.4 mg/100 g fresh wt) and then decreased, remaining very low at 4 WAH (1.4 mg/100 g fresh wt). As for the levels of fructose and glucose, their levels shifted up to 2230.8 and 845.2 mg/100 g fresh wt at 2 and 3 WAHs, then the levels lessened to their lowest concentration. The levels of the three acids were high at the beginning, except malic acid level at 2 WAH, all acids leveled off through the latter weeks of post harvest period. In the fruit studied, the levels of saturated palmitic acid (16:0) and stearic acid (18:0), and unsaturated oleic acid (18:1), linoleic acid (18:2n-6) and linolenic acid (18:3n-3) were most abundant fatty acids detected throughout medlar ripening (pulp softening and darkening). The level of palmitic and stearic acids as well as the level of linoleic and linolenic acids were the highest at 1 WAH and then suddenly decreased as the medlar soften and the pulp becomes slightly (2 WAH) and fully (3 WAH) brown through 2 and 4 WAHs. In addition to these prominent fatty acids, a remarkable decrease was also obtained in the content of some other fatty acids (C10–15, C16:1, C20–24).