There is a close relationship between the susceptibility to disease and nutritional state, in the sense that an adequate diet enhances resistance to disease. There is an increasing interest in this beneficial relationship among scientists, food manufacturers and consumers. The trend is moving towards functional foods and their specific health benefits. The results of numerous epidemiological studies and recent clinical trials provide consistent evidence that diets rich in fruits and vegetables can reduce the risk of chronic diseases. These protective effects are mediated through multiple groups of beneficial nutrients contained in the fruits and vegetables, one of these being polyphenol antioxidants. The intake of the polyphenols plays an important role in the reduction and prevention of coronary heart disease (CHD), cardiovascular disease and cancer, as a consequence of their associated antioxidant properties. Fruits contain an array of polyphenols with antioxidant capacity. Polyphenols may be classified in two broad groups namely: flavonoids and non-flavonoids. Flavonoid subgroups in fruits are further grouped as catechins, anthocyanins, procyanidins and flavonol among others. Phenolic acids occur as hydroxylated derivatives of benzoic acid and cinnarnic acid, and are classified as non-flavonoids. Polyphenols have redox properties allowing them to act as reducing agents, hydrogen donators and singlet oxygen quenchers, and thus contribute to the antioxidant capacity of fruits and vegetables. Because of the numerous beneficial effects attributed to these antioxidants, there is renewed interest in finding vegetal species with high phenolic content and relevant biological activities. In view of the importance of these substances towards health and food chemistry, this study will focus on the polyphenol and Vitamin C characterisation and quantification of an indigenous South African fruit, the Kei-apple (Dovyalis cafra), thought to have antioxidant properties. Due to the fact that polyphenol content influences the colour, taste and possible health benefits of the fruit / processed food product, this study will supply valuable information to industry in choosing the best fruit processing methods to attain the desired end product. The exploitation of indigenous South African fruits (Marula and Kei-apple) is receiving increasing prominence, not only due to their health benefits, but also the opportunities these present to rural based economics. Furthermore, this research will serve as a platform for further research on the Kei-apple and other indigenous South African fruits with possible health benefits. Aims: The overall aim of this study is the quantification and characterisation of various nutritionally important antioxidants (polyphenols and ascorbate) in the Kei-apple fruit in its entirety, as well as in its individual fruit components (peel, flesh and seeds). In addition, the total antioxidant capacity of the entire fruit and the various fruit components will be determined in the unfractionated and fractionated fruit extracts. Gas chromatography coupled mass spectrometry (GC-MS) characterisation of the individual polyphenol components will also be analyzed in order to speculate on possible specific health benefits which the Kei-apple may possess. Methods: The study was designed to ensure that a representative fruit sample was collected. Approximately 100 kg Kei-apples were picked in the month of November 2004 from the Bloemhof area in South Africa. A sample of 50 fruits was rinsed and separated into the various components (peel, flesh and seeds). An additional 50 fruits were randomly selected, cleaned and used in their entirety for data representative of the entire fruit. The sample extracts were prepared, after being grounded and lyophilized, by a method described by Eihkonen et al. (1999) using 70% aqueous acetone. The C18-fractionation on the fruit and separated fruit components resulted in four fractions containing (1) phenolic acids; (2) procyanidins, catechins and anthocyanin monomers; (3) flavonols and (4) anthocyanin polymers. The total polyphenol content of the fruit and fruit components as well as the above mentioned C18-fractions were determined by Folin-Ciocalteu's method (Singleton & Rossi, 1965). Both free and total ascorbate concentrations in these samples were determined as described by Beutler (1984), in addition to total sugar content of these via standard methods. Apart from their nutritional interest, both these measurements are necessary for the correction of the total polyphenol concentrations. The total antioxidant capacity of the entire fruit and various fruit components was determined by measuring the oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) of the unfractionated and fractionated extracts. Using GC-MS analysis, the various individual polyhenol compounds contributing to the total polyphenol content of the Kei-apple was separated, identified and quantified. This quantitative data was captured and statistically analysed. The analysis of variation was performed using the Tukey Honest Significant Difference test for post-hoc comparison. ORAC, FRAP and polyphenol Pearson correlation analyses were performed using Statistics (Statsoft Inc., Tulsa, Oklahoma, USA) with significance set at P ≤ 0.05. Results and discussion: This study determined the presence of various nutritionally important antioxidants (polyphenols and ascorbate), the total antioxidant capacity in the entire fruit as well as in the individual fruit components (peel, flesh and seeds) and their polyphenol sub group fractions. Total phenol content: The Kei-apple, in its entirety, has a polyphenol concentration of 943 ± 20.3 mg GAE/100g dry weight. Comparison of the individual fruit components showed the seeds to have the highest total polyphenol concentration with 1990 ± 31.3 mg GAE/100g dry weight, followed by that of the peel, 1126 ± 45.8 mg GAE/100g dry weight and then that of the flesh, 521 ± 1.01 mg GAE/100g dry weight. Total, L-ascorbic (ASC) and L-dehydroascobic (DHA) concentration: The total ascorbate of Kei-apple fruit is 517 ± 0.92 mg/100g dry weight. In contrast to the polyphenol content, the flesh of the Kei-apple had significantly the highest concentration of total ascorbate 778 ± 1.20 mg/100g dry weight, Gascorbic 241 ± 21.0 mg/100g dry weight, as well as Gdehydroascobic 537 ± 22.2 mg/100g dry weight. The ratio of Lascorbic acidltotal ascorbate for the flesh, entire fruit, peel and seed is 0.31,0.43,0.49,0.95, respectively, indicating the seeds are the most stable source of biologically active Vitamin C, with 95% of the total ascorbate occurring as G ascorbate. This is also in line with the total polyphenol content of these components, confirming a polyphenol sparing effect on ascorbate. C18-fractionation extracts: Solid phase (C18) fractionation of the Kei-apple fruit and fruit components showed that the fruit, peels and seeds consist predominantly of phenolic acids, followed by procyanidin, catechin and anthocyanin monomers and thereafter varying amounts of anthocyanin polymers and flavonols. Antioxidant capacity: The antioxidant capacity of the entire fruit and individual fruit components as determined by ORAC, (r=0.76) and FRAP, (r=0.95) significantly correlated with the total polyphenol content, as well as to each other (r=0.88), indicating both to be good predictors of antioxidant capacity. GC-MS polyphenol characterisation of the Kei-apple: Caffeic acid and hydro-p-coumaric acid were seen to be the phenolic acids occurring in the highest concentrations in the Kei-apple fruit. The majority of these are concentrated in the flesh and in the case of caffeic acid, also in the peel. The order of predominance of other major non-flavonoid components in the whole fruit analysis are m-hydroxybenzoic acid > p-hydroxyphenyl acetic acid > 3-methoxy-4- hydroxyphenylpropionic acid > p-coumaric acid. The peel of the Kei-apple, apart from caffeic acid, has exceptionally high concentrations of ferulic acid and also serves as a source of protocatechuic acid. Syringic acid was most prominent in the seeds. Although the total flavonoid concentration in the Kei-apple was low, taxifolin and catechin were identified and the seeds almost entirely accounting for these. Conclusion: From this study it was concluded the Kei-apple is a rich source of antioxidant compounds (polyphenols and ascorbate), with a strong antioxidant capacity, and hence may be associated with health promotion properties, particularly in the prevention of cancer, cardiovascular disease, and neurodegeneration. Additionally, due to the increased scientific and commercial interest in this fruit, it is essential to take into consideration the various factors (agronomic, genomic, pre- and post harvest condition and processing) and tissues. This might affect the chemical composition of the final marketed product, which may play a significant role in determining the polyphenol and ascorbate composition and bioactivity of these compounds during food processing procedures. Hence, the polyphenol composition of the various fruit components should be taken into consideration when selecting a method of fruit processing into the desired end product. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.

There is a close relationship between the susceptibility to disease and nutritional state, in the sense that an adequate diet enhances resistance to disease. There is an increasing interest in this beneficial relationship among scientists, food manufacturers and consumers. The trend is moving towards functional foods and their specific health benefits. The results of numerous epidemiological studies and recent clinical trials provide consistent evidence that diets rich in fruits and vegetables can reduce the risk of chronic diseases. These protective effects are mediated through multiple groups of beneficial nutrients contained in the fruits and vegetables, one of these being polyphenol antioxidants. The intake of the polyphenols plays an important role in the reduction and prevention of coronary heart disease (CHD), cardiovascular disease and cancer, as a consequence of their associated antioxidant properties. Fruits contain an array of polyphenols with antioxidant capacity. Polyphenols may be classified in two broad groups namely: flavonoids and non-flavonoids. Flavonoid subgroups in fruits are further grouped as catechins, anthocyanins, procyanidins and flavonol among others. Phenolic acids occur as hydroxylated derivatives of benzoic acid and cinnarnic acid, and are classified as non-flavonoids. Polyphenols have redox properties allowing them to act as reducing agents, hydrogen donators and singlet oxygen quenchers, and thus contribute to the antioxidant capacity of fruits and vegetables. Because of the numerous beneficial effects attributed to these antioxidants, there is renewed interest in finding vegetal species with high phenolic content and relevant biological activities. In view of the importance of these substances towards health and food chemistry, this study will focus on the polyphenol and Vitamin C characterisation and quantification of an indigenous South African fruit, the Kei-apple (Dovyalis cafra), thought to have antioxidant properties. Due to the fact that polyphenol content influences the colour, taste and possible health benefits of the fruit / processed food product, this study will supply valuable information to industry in choosing the best fruit processing methods to attain the desired end product. The exploitation of indigenous South African fruits (Marula and Kei-apple) is receiving increasing prominence, not only due to their health benefits, but also the opportunities these present to rural based economics. Furthermore, this research will serve as a platform for further research on the Kei-apple and other indigenous South African fruits with possible health benefits. Aims: The overall aim of this study is the quantification and characterisation of various nutritionally important antioxidants (polyphenols and ascorbate) in the Kei-apple fruit in its entirety, as well as in its individual fruit components (peel, flesh and seeds). In addition, the total antioxidant capacity of the entire fruit and the various fruit components will be determined in the unfractionated and fractionated fruit extracts. Gas chromatography coupled mass spectrometry (GC-MS) characterisation of the individual polyphenol components will also be analyzed in order to speculate on possible specific health benefits which the Kei-apple may possess. Methods: The study was designed to ensure that a representative fruit sample was collected. Approximately 100 kg Kei-apples were picked in the month of November 2004 from the Bloemhof area in South Africa. A sample of 50 fruits was rinsed and separated into the various components (peel, flesh and seeds). An additional 50 fruits were randomly selected, cleaned and used in their entirety for data representative of the entire fruit. The sample extracts were prepared, after being grounded and lyophilized, by a method described by Eihkonen et al. (1999) using 70% aqueous acetone. The C18-fractionation on the fruit and separated fruit components resulted in four fractions containing (1) phenolic acids; (2) procyanidins, catechins and anthocyanin monomers; (3) flavonols and (4) anthocyanin polymers. The total polyphenol content of the fruit and fruit components as well as the above mentioned C18-fractions were determined by Folin-Ciocalteu's method (Singleton & Rossi, 1965). Both free and total ascorbate concentrations in these samples were determined as described by Beutler (1984), in addition to total sugar content of these via standard methods. Apart from their nutritional interest, both these measurements are necessary for the correction of the total polyphenol concentrations. The total antioxidant capacity of the entire fruit and various fruit components was determined by measuring the oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) of the unfractionated and fractionated extracts. Using GC-MS analysis, the various individual polyhenol compounds contributing to the total polyphenol content of the Kei-apple was separated, identified and quantified. This quantitative data was captured and statistically analysed. The analysis of variation was performed using the Tukey Honest Significant Difference test for post-hoc comparison. ORAC, FRAP and polyphenol Pearson correlation analyses were performed using Statistics (Statsoft Inc., Tulsa, Oklahoma, USA) with significance set at P ≤ 0.05. Results and discussion: This study determined the presence of various nutritionally important antioxidants (polyphenols and ascorbate), the total antioxidant capacity in the entire fruit as well as in the individual fruit components (peel, flesh and seeds) and their polyphenol sub group fractions. Total phenol content: The Kei-apple, in its entirety, has a polyphenol concentration of 943 ± 20.3 mg GAE/100g dry weight. Comparison of the individual fruit components showed the seeds to have the highest total polyphenol concentration with 1990 ± 31.3 mg GAE/100g dry weight, followed by that of the peel, 1126 ± 45.8 mg GAE/100g dry weight and then that of the flesh, 521 ± 1.01 mg GAE/100g dry weight. Total, L-ascorbic (ASC) and L-dehydroascobic (DHA) concentration: The total ascorbate of Kei-apple fruit is 517 ± 0.92 mg/100g dry weight. In contrast to the polyphenol content, the flesh of the Kei-apple had significantly the highest concentration of total ascorbate 778 ± 1.20 mg/100g dry weight, Gascorbic 241 ± 21.0 mg/100g dry weight, as well as Gdehydroascobic 537 ± 22.2 mg/100g dry weight. The ratio of Lascorbic acidltotal ascorbate for the flesh, entire fruit, peel and seed is 0.31,0.43,0.49,0.95, respectively, indicating the seeds are the most stable source of biologically active Vitamin C, with 95% of the total ascorbate occurring as G ascorbate. This is also in line with the total polyphenol content of these components, confirming a polyphenol sparing effect on ascorbate. C18-fractionation extracts: Solid phase (C18) fractionation of the Kei-apple fruit and fruit components showed that the fruit, peels and seeds consist predominantly of phenolic acids, followed by procyanidin, catechin and anthocyanin monomers and thereafter varying amounts of anthocyanin polymers and flavonols. Antioxidant capacity: The antioxidant capacity of the entire fruit and individual fruit components as determined by ORAC, (r=0.76) and FRAP, (r=0.95) significantly correlated with the total polyphenol content, as well as to each other (r=0.88), indicating both to be good predictors of antioxidant capacity. GC-MS polyphenol characterisation of the Kei-apple: Caffeic acid and hydro-p-coumaric acid were seen to be the phenolic acids occurring in the highest concentrations in the Kei-apple fruit. The majority of these are concentrated in the flesh and in the case of caffeic acid, also in the peel. The order of predominance of other major non-flavonoid components in the whole fruit analysis are m-hydroxybenzoic acid > p-hydroxyphenyl acetic acid > 3-methoxy-4- hydroxyphenylpropionic acid > p-coumaric acid. The peel of the Kei-apple, apart from caffeic acid, has exceptionally high concentrations of ferulic acid and also serves as a source of protocatechuic acid. Syringic acid was most prominent in the seeds. Although the total flavonoid concentration in the Kei-apple was low, taxifolin and catechin were identified and the seeds almost entirely accounting for these. Conclusion: From this study it was concluded the Kei-apple is a rich source of antioxidant compounds (polyphenols and ascorbate), with a strong antioxidant capacity, and hence may be associated with health promotion properties, particularly in the prevention of cancer, cardiovascular disease, and neurodegeneration. Additionally, due to the increased scientific and commercial interest in this fruit, it is essential to take into consideration the various factors (agronomic, genomic, pre- and post harvest condition and processing) and tissues. This might affect the chemical composition of the final marketed product, which may play a significant role in determining the polyphenol and ascorbate composition and bioactivity of these compounds during food processing procedures. Hence, the polyphenol composition of the various fruit components should be taken into consideration when selecting a method of fruit processing into the desired end product. / Thesis (M.Sc. (Nutrition))--North-West University, Potchefstroom Campus, 2007.

Darbo tikslas: ištirti juodųjų serbentų (Ribes nigrum L.) produktų, pasižyminčių antioksidantinėmis savybėmis įtaką triušių virškinimo procesams ir produktyvumui. Darbo tikslas įgyvendintas sprendžiant šiuos uždavinius: 1) aukštos apykaitynės energijos gautos iš padidinto riebalų kiekio racionų sudarymas, žolės miltus pakeičiant juodųjų serbentų išspaudomis; 2) nustatyti triušių kūno svorio, priesvorio, pašarų sąnaudų su juodaisiais serbentais sąveiką; 3) ištirti juodųjų serbentų išspaudų įtaką atskirų virškinimo trakto segmentų turinio pH ir sausųjų medžiagų kiekiui;4) nustatyti juodųjų serbentų išspaudų įtaką klubinės žarnos turinio klampumui, aklosios žarnos turinio amoniako kiekiui; 5) ištirti trumpųjų grandinių riebalų rūgščių (TGRR) koncentraciją ir sudėtį aklojoje žarnoje; 6) nustatyti juodųjų serbentų išspaudų įtaką aklosios ir gaubtinės žarnų turinio baltymų, bakterijų fermentiniams (α- ir β-galaktozidaziniams, gliukozidaziniams, α- ir β-gliukozidaziniams ir β-gliukuronidazidaziniams) aktyvumams ir lakiųjų riebalų rūgščių (LRR) kiekiams; 7) nustatyt ipoveikį triušių antioksidantinio aktyvumo rodikliams; 8) nustatyti poveikį biocheminiams kraujo rodikliams; 9) ištirti triušių aterogeniškumo ir atsparumo insulinui rodiklius. Išvados: 1) Juodųjų serbentų išspaudų naudojimas pakeičiant žolės miltus, patvirtino hipotezę, kad jos gali būti laikomos veiksminga ir prieinama pašarų sudedamąją dalimi triušių racionuose. 2) Raciono papildymas juodųjų serbentų išspaudomis... [toliau žr. visą tekstą] / Researches were conducted in the Animal Husbandry Department of the Veterinary Academy of Lithuanian Health Sciences University, also in the vivarium of Lithuanian Veterinary Academy and in the Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences. New Zealand rabbits were used for the researches. All rabbits were calved over one cycle of reproduction (50 percent were male and 50 percent were female). All rabbits were assigned to four groups of five individuals each. The rabbits of the control group (K) were fed a standard diet; the group KP was fed a standard diet with increased fat volume. The rabbits of the group E were subjected to a standard diet with the addition of blackcurrant polyphenolic extract (1,5 percent), the animals of the group EP were fed a standard diet with increased fat volume + blackcurrant extract (1,5 percent). Duration of the research was 45 days. Rabbits were stored in the individual flat-bottomed wire cages in closed room. Over the research all rabbits were fed and watered ad libitum. The research included observation of rabbit growth dynamics, level of ammonia in the substance of cecum, activity of microbe ferments, short-chain fatty acids, and research of overall wellness. Thegoalofthepaper: to investigate the effect of blackcurrant (Ribes nigrum L.) products distinguishing for antioxidant features on digestive processes and productivity of rabbits. The goal of the paper has been achieved by solving the following... [to full text]

The influence of cultivar and maturity on polyphenolic composition and antioxidant activity was investigated by UV-Visible spectrophotometry and analytical high performance liquid chromatography (HPLC) in commercially important blackberry cultivars and selections. The anthocyanin pigments changed tremendously with ripening. Total anthocyanins increased from 74.7-317 mg/100g fw from underripe to over ripe for 'Marion', and from 69.9-164 mg/100g fw for 'Evergreen'. Total phenolics did not show marked change with maturity with values slightly decreasing from underripe to ripe. Antioxidant activities, while increasing with ripening, did not show the noticeable change that total anthocyanins exhibited. The total phenolic and total anthocyanin contents varied greatly among 11 cultivars. Total anthocyanins ranged from 131-256 mg/100g fw (mean = 198), total phenolics from 682-1056 mg GAE/100g fw (mean = 900), ORAC from 37.6-75.5 μmolTE/g fw (mean = 50.2), and FRAP ranged from 63.5- 91.5 μmolTE/g fw (mean = 77.5). Four blackberry cultivars were found to be higher in total anthocyanins and total phenolics than 'Marion' and 'Evergreen', the predominant commercial cultivars in the Pacific Northwest. The results from these studies confirmed that blackberries are a good source of natural antioxidants and colorant, and demonstrated the potential for obtaining new cultivars with high pigment/phenolic content through classical plant breeding. The investigation on the incidence of haze and sediment formation revealed that the sediment in the commercial reconstituted 'Evergreen' blackberry (CRE) juice was composed of ellagic acid, protein, and unidentified compounds. The qualitative tannin and protein-tannin haze test indicated that the sediment was predominantly tannin or protein-tannin complexes. Nitrogen determination showed the sediment to be 6.69 ± 2.21% (w/w) protein on a dry weight basis. Almost all of the extractable material was identified as ellagic acid by HPLC and LC-MS. The ellagic acid content of the wet sediment was 0.05 g/100g while it was 7.41 g/100g in freeze-dried sediment. Tannase enzyme did not significantly decrease the concentration of ellagitannins in 'Marion' blackberry juice in this study. / Graduation date: 2004

Copy of author's previously published article inserted. / Bibliography: leaves 180-195. / xii, 195 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigation of the contribution of polyphenol oxidase (PPO) and peroxidase (POD) to enzymic browning in sugarcane juice. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1995

Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Food Science." Includes bibliographical references (p. 130-152).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 263-290).

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Nutritional Sciences." Includes bibliographical references (p. 104-127).

Thesis (M. Phil.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 101-124) Also available in print.