Th e biologically active compounds, especially fruit phenolics, are responsible for reduced risk ... more Th e biologically active compounds, especially fruit phenolics, are responsible for reduced risk of developing chronic diseases (cardiovascular disease, cancer, diabetes, etc.), due to their antioxidant activities. Th is study summarized some chemical principles of antioxidant capacity assays and the antioxidant capacity of selected fruit varieties (strawberry, sour cherry, cornelian cherry, blackthorn). We determined the contents of total phenolics (TPC), total fl avonoids (TF), total non-fl avonoids (TNF) and total anthocyanins (TA) in selected fruits. Th e content of TPC, TF and TNF in fruits was analyzed by Folin-Ciocalteu colorimetric method, while the TA content of extracts was determined by bisulphite bleaching method. Total antioxidant capacity (TAC) of selected fruits were analyzed using 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS), 2,2-diphenil-1-picrylhydrazyl radical scavenging capacity (DPPH), ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). Cornelian cherry had the highest content of TPC, while sour cherry cv. Marasca had the highest content of TA. TAC was the highest in cornelian cherry fruits and decreased in other fruits as follow: sour cherry, blackthorn and strawberry. Th e fruit extracts had diff erent TAC in relation to the method applied, and the diff erent TAC of fruits can be ascribed to their TPC, TF, TNF or TA content. Th ere was a direct correlation between the TAC determined using DPPH and ORAC methods and the TA content of fruit extracts. Using FRAP method correlation was weaker, but using ABTS method correlation was not observed. Th e ripping correlation between TF or TNF and TAC was observed using ABTS and ORAC methods.
This paper reports about the content of polyphenols and volatiles in fresh fruits of two sour che... more This paper reports about the content of polyphenols and volatiles in fresh fruits of two sour cherry cultivars (Marasca and Obla~inska), some berry fruits (strawberry Maya, raspberry Willamette and wild blueberry) and the corresponding low sugar jams. Phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols and flavonols) were determined by high-performance liquid chromatography (HPLC). Those found in the fruits were also found in the jams. Jams contained lower amounts of polyphenols than fresh fuits, but their overall retention in jams was relatively high. Among fruits, sour cherry Marasca had the highest level of polyphenols, while sour cherry Marasca jam and raspberry Willamette jam had the highest level of polyphenols among jams. The major flavonoid in all investigated fruits, except in sour cherry Obla~inska, was (-)-epicatechin. Sour cherry Marasca had the highest level of (-)-epicatechin (95.75 mg/kg), and it also contained very high amounts of flavonols, derivatives of quercetin and kaempferol. Hydroxybenzoic acids (HBAs) were not found in sour cherries Marasca and Obla~inska, but were found in berry fruits and jams. Phenolic compound (+)-gallocatechin was found only in Marasca fruit and jam. Ellagic acid was found in the highest concentration in raspberry Willamette fruit and jam. Hydroxycinnamic acids (HCAs) were found in all the investigated fruits, with the exception of a derivative of ferulic acid, which was not found in strawberry. Derivatives of caffeic, p-coumaric and chlorogenic acids were found in all the investigated fruits, with chlorogenic acid being the most abundant, especially in sour cherry Marasca. Volatiles were determined by gas chromatography (GC) and expressed as the peak area of the identified compounds. All investigated volatiles of fresh fruit were also determined in the related jams with relatively high retention. Sour cherries Marasca and Obla~inska contained the same volatile compounds, but Marasca had higher level of total volatiles. The main volatile compound in both sour cherry cultivars was benzaldehyde (characteristic cherry aroma compound), which was followed by hexanal, 2-hexenal, 2-heptanone, linalool, nerol, and a-terpineol. Our results show that g-decalactone and linalool were the most abundant volatile compounds in strawberry Maya and raspberry Willamette, respectively. The most abundant group of volatiles in wild bluberry was esters, and they were followed by terpenes, ethyl butanoate and linalool.
Sensory quality is important in assessing cultivars for fresh consumption as well as for the proc... more Sensory quality is important in assessing cultivars for fresh consumption as well as for the processing industry. Important quality attributes for fresh consumption were found to be colour, taste, fl avour and texture attributes. Strawberries (Fragaria x ananassa Duch.) have unique, highly desirable taste and fl avour and are one of the most important cultivated berry fruits in Croatia. Today, consumers are increasingly better informed about diet and health, and as a result, desire more "healthy" food, which off er high quality, safety and optimum nutrient balance. Th e increasing demand for organic food has focused interest based on claims that an organic product tastes "diff erent", is "preferred" and is "more healthy". It has implicit expectation that the improvement is due to the way the food is grown. Th e topic of organic food and organic agriculture attracts considerable public, commercial and research interest. Th e purpose of the present investigation was to profi le the sensory characteristics of fresh fruit and its purées in two strawberry cultivars, 'Maya' and 'Queen Elisa', conventionally and organically grown in Croatia.
During the ripening of three apricot cultivars (''Keckemetska ruza'', ''Madjarska najbolja'' and ... more During the ripening of three apricot cultivars (''Keckemetska ruza'', ''Madjarska najbolja'' and ''Velika rana'') grown in two different geographical region of Croatia the changes of polyphenols and carotenoids were determined by using high-performance liquid chromatography (HPLC) with UV-Vis photo diode array detection. The content of individual polyphenols during ripening was quite similar, whereas their amount differed significantly. Immature fruits showed the highest level of polyphenols, which decreased at semi-mature fruits and did not change remarkably in commercial mature fruits. Among polyphenols, flavan-3-ols, chlorogenic acid and quercetin-3-rutinoside were dominant in all ripening stages of all apricot cultivars. The quantity of polyphenols during apricot fruits ripening depended on cultivars, while the region of cultivation did not have remarkable influence on polyphenols amount. During ripening carotenoids increased significantly especially b-carotene which represented 70-85% of the total carotenoid content. Besides b-carotene, in all apricot cultivars c-carotene was found. a-Carotene, zeaxantin and lutein were found in cv. ''Madjarska najbolja'' and in cv. ''Velika rana'' a-carotene and lutein were determined. The region of cultivation and the cultivar were important factors, which influenced the carotenoid amount of apricot fruits, and this content was higher in cultivars grown in Mediterranean region.
Sensory analysis was performed on fresh fruits, purées and low-calorie jams prepared in laborator... more Sensory analysis was performed on fresh fruits, purées and low-calorie jams prepared in laboratory conditions and under vacuum in three strawberry cultivars, Honeoye, Clery and NF 421, grown in Croatia. The purpose of this study was to characterize and compare the sensory quality of three different strawberry cultivars in fresh and processed strawberries. Quantitative descriptive analysis was used to establish sensory profiles. The results of investigation were presented by means of multivariate modelling methods, such as principal component analysis (PCA), which established that analysed sensory attributes can clearly be connected to different cultivars in fresh samples, purées and in all examined jams. The results established during this study on sensory profiles of fresh strawberries and their purées and jams represent a great contribution to the characterization of sensory profiles of these nutritionally high-valued products.
Th e biologically active compounds, especially fruit phenolics, are responsible for reduced risk ... more Th e biologically active compounds, especially fruit phenolics, are responsible for reduced risk of developing chronic diseases (cardiovascular disease, cancer, diabetes, etc.), due to their antioxidant activities. Th is study summarized some chemical principles of antioxidant capacity assays and the antioxidant capacity of selected fruit varieties (strawberry, sour cherry, cornelian cherry, blackthorn). We determined the contents of total phenolics (TPC), total fl avonoids (TF), total non-fl avonoids (TNF) and total anthocyanins (TA) in selected fruits. Th e content of TPC, TF and TNF in fruits was analyzed by Folin-Ciocalteu colorimetric method, while the TA content of extracts was determined by bisulphite bleaching method. Total antioxidant capacity (TAC) of selected fruits were analyzed using 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS), 2,2-diphenil-1-picrylhydrazyl radical scavenging capacity (DPPH), ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC). Cornelian cherry had the highest content of TPC, while sour cherry cv. Marasca had the highest content of TA. TAC was the highest in cornelian cherry fruits and decreased in other fruits as follow: sour cherry, blackthorn and strawberry. Th e fruit extracts had diff erent TAC in relation to the method applied, and the diff erent TAC of fruits can be ascribed to their TPC, TF, TNF or TA content. Th ere was a direct correlation between the TAC determined using DPPH and ORAC methods and the TA content of fruit extracts. Using FRAP method correlation was weaker, but using ABTS method correlation was not observed. Th e ripping correlation between TF or TNF and TAC was observed using ABTS and ORAC methods.
This paper reports about the content of polyphenols and volatiles in fresh fruits of two sour che... more This paper reports about the content of polyphenols and volatiles in fresh fruits of two sour cherry cultivars (Marasca and Obla~inska), some berry fruits (strawberry Maya, raspberry Willamette and wild blueberry) and the corresponding low sugar jams. Phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols and flavonols) were determined by high-performance liquid chromatography (HPLC). Those found in the fruits were also found in the jams. Jams contained lower amounts of polyphenols than fresh fuits, but their overall retention in jams was relatively high. Among fruits, sour cherry Marasca had the highest level of polyphenols, while sour cherry Marasca jam and raspberry Willamette jam had the highest level of polyphenols among jams. The major flavonoid in all investigated fruits, except in sour cherry Obla~inska, was (-)-epicatechin. Sour cherry Marasca had the highest level of (-)-epicatechin (95.75 mg/kg), and it also contained very high amounts of flavonols, derivatives of quercetin and kaempferol. Hydroxybenzoic acids (HBAs) were not found in sour cherries Marasca and Obla~inska, but were found in berry fruits and jams. Phenolic compound (+)-gallocatechin was found only in Marasca fruit and jam. Ellagic acid was found in the highest concentration in raspberry Willamette fruit and jam. Hydroxycinnamic acids (HCAs) were found in all the investigated fruits, with the exception of a derivative of ferulic acid, which was not found in strawberry. Derivatives of caffeic, p-coumaric and chlorogenic acids were found in all the investigated fruits, with chlorogenic acid being the most abundant, especially in sour cherry Marasca. Volatiles were determined by gas chromatography (GC) and expressed as the peak area of the identified compounds. All investigated volatiles of fresh fruit were also determined in the related jams with relatively high retention. Sour cherries Marasca and Obla~inska contained the same volatile compounds, but Marasca had higher level of total volatiles. The main volatile compound in both sour cherry cultivars was benzaldehyde (characteristic cherry aroma compound), which was followed by hexanal, 2-hexenal, 2-heptanone, linalool, nerol, and a-terpineol. Our results show that g-decalactone and linalool were the most abundant volatile compounds in strawberry Maya and raspberry Willamette, respectively. The most abundant group of volatiles in wild bluberry was esters, and they were followed by terpenes, ethyl butanoate and linalool.
Sensory quality is important in assessing cultivars for fresh consumption as well as for the proc... more Sensory quality is important in assessing cultivars for fresh consumption as well as for the processing industry. Important quality attributes for fresh consumption were found to be colour, taste, fl avour and texture attributes. Strawberries (Fragaria x ananassa Duch.) have unique, highly desirable taste and fl avour and are one of the most important cultivated berry fruits in Croatia. Today, consumers are increasingly better informed about diet and health, and as a result, desire more "healthy" food, which off er high quality, safety and optimum nutrient balance. Th e increasing demand for organic food has focused interest based on claims that an organic product tastes "diff erent", is "preferred" and is "more healthy". It has implicit expectation that the improvement is due to the way the food is grown. Th e topic of organic food and organic agriculture attracts considerable public, commercial and research interest. Th e purpose of the present investigation was to profi le the sensory characteristics of fresh fruit and its purées in two strawberry cultivars, 'Maya' and 'Queen Elisa', conventionally and organically grown in Croatia.
During the ripening of three apricot cultivars (''Keckemetska ruza'', ''Madjarska najbolja'' and ... more During the ripening of three apricot cultivars (''Keckemetska ruza'', ''Madjarska najbolja'' and ''Velika rana'') grown in two different geographical region of Croatia the changes of polyphenols and carotenoids were determined by using high-performance liquid chromatography (HPLC) with UV-Vis photo diode array detection. The content of individual polyphenols during ripening was quite similar, whereas their amount differed significantly. Immature fruits showed the highest level of polyphenols, which decreased at semi-mature fruits and did not change remarkably in commercial mature fruits. Among polyphenols, flavan-3-ols, chlorogenic acid and quercetin-3-rutinoside were dominant in all ripening stages of all apricot cultivars. The quantity of polyphenols during apricot fruits ripening depended on cultivars, while the region of cultivation did not have remarkable influence on polyphenols amount. During ripening carotenoids increased significantly especially b-carotene which represented 70-85% of the total carotenoid content. Besides b-carotene, in all apricot cultivars c-carotene was found. a-Carotene, zeaxantin and lutein were found in cv. ''Madjarska najbolja'' and in cv. ''Velika rana'' a-carotene and lutein were determined. The region of cultivation and the cultivar were important factors, which influenced the carotenoid amount of apricot fruits, and this content was higher in cultivars grown in Mediterranean region.
Sensory analysis was performed on fresh fruits, purées and low-calorie jams prepared in laborator... more Sensory analysis was performed on fresh fruits, purées and low-calorie jams prepared in laboratory conditions and under vacuum in three strawberry cultivars, Honeoye, Clery and NF 421, grown in Croatia. The purpose of this study was to characterize and compare the sensory quality of three different strawberry cultivars in fresh and processed strawberries. Quantitative descriptive analysis was used to establish sensory profiles. The results of investigation were presented by means of multivariate modelling methods, such as principal component analysis (PCA), which established that analysed sensory attributes can clearly be connected to different cultivars in fresh samples, purées and in all examined jams. The results established during this study on sensory profiles of fresh strawberries and their purées and jams represent a great contribution to the characterization of sensory profiles of these nutritionally high-valued products.
Uploads
Papers by D. Kovačević