Effects of cell wall degradation on the polyphenol content and profile of red berries during juice production (Band 9) PDF Download
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Author: Lena Rebecca Larsen
Publisher: Cuvillier Verlag
ISBN: 3736965184
Category : Science
Languages : en
Pages : 164
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Book Description
The quality of red juices is strongly determined by their content of anthocyanins since these are responsible for the nutritional value and organoleptic properties. The final anthocyanin concentration greatly depends on juice production and, more specifically, on the disintegration of the pectic substances in the cell walls during maceration which increases anthocyanin extractability. This work evaluates the potential of ultrasound treatment during enzymatic maceration to enhance pectin degradation. The application of this technique allows for gentle processing conditions regarding temperature and time compared to the conventional enzymatic treatment. Concurrently, the arising pool of soluble pectic oligosaccharides and polysaccharides can be increased which beneficially affects anthocyanin stability by complexation. The resulting interactions are multifaceted depending on the structural properties of both involved compounds. This thesis expands the knowledge of the molecular mechanisms of pectin degradation leading to soluble polymers that increase the stability of anthocyanins by complexation.
Author: Lena Rebecca Larsen
Publisher: Cuvillier Verlag
ISBN: 3736965184
Category : Science
Languages : en
Pages : 164
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Book Description
The quality of red juices is strongly determined by their content of anthocyanins since these are responsible for the nutritional value and organoleptic properties. The final anthocyanin concentration greatly depends on juice production and, more specifically, on the disintegration of the pectic substances in the cell walls during maceration which increases anthocyanin extractability. This work evaluates the potential of ultrasound treatment during enzymatic maceration to enhance pectin degradation. The application of this technique allows for gentle processing conditions regarding temperature and time compared to the conventional enzymatic treatment. Concurrently, the arising pool of soluble pectic oligosaccharides and polysaccharides can be increased which beneficially affects anthocyanin stability by complexation. The resulting interactions are multifaceted depending on the structural properties of both involved compounds. This thesis expands the knowledge of the molecular mechanisms of pectin degradation leading to soluble polymers that increase the stability of anthocyanins by complexation.
Author: J. B. Adams
Publisher:
ISBN:
Category :
Languages : en
Pages : 136
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Book Description
Author: Esteban I. Mejia-Meza
Publisher:
ISBN:
Category : Antioxidants
Languages : en
Pages : 326
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Book Description
Author: Katrina E. Kelly
Publisher:
ISBN:
Category : Cold storage
Languages : en
Pages : 103
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Book Description
Plants inherently produce polyphenols (i.e., antioxidants) as a response to reduce oxidative stress caused by abusive environmental pre- and postharvest conditions. These antioxidants, as well as vitamin C, are present in considerable levels in strawberries; however, excessive oxidative stress brought on by improper postharvest handling conditions can reduce the levels of antioxidants in the fruit and shorten the shelf-life of strawberries. Nevertheless, it may be possible to utilize strawberrys naturally occurring polyphenols to reduce postharvest stress and extend their shelf life. The polyphenolic profile has been previously investigated in several strawberry cultivars, however no studies have determined the unique polyphenolic profiles of three important Florida strawberry cultivars (Florida Radiance, Sweet Sensation® Florida 127 and Florida Beauty) at harvest and during cold storage. Therefore, in order to better understand the distribution of individual polyphenols within these cultivars and their impact on postharvest shelf-life, this study examined the polyphenolic profiles throughout 7 days of cold storage (1 °C) using an HPLC-DAD. The activity of phenylalanine ammonia lyase (PAL), a key enzyme in the biosynthesis of polyphenols, and polyphenol oxidase (PPO), the enzyme responsible for polyphenol degradation, were also examined during cold storage to understand their possible influences on postharvest synthesis or degradation of polyphenols. This study revealed that the polyphenolic profile of strawberry fruit was genotype dependent; however, pelargonidin 3-glucoside was consistently the anthocyanin found in higher concentrations in the fruit regardless of the cultivar. Apart from the anthocyanins, the flavonols showed the most variation among the three cultivars. PAL was slightly induced during strawberry postharvest storage suggesting that a stress response occurred during cold storage while PPO showed variable induction patterns across all three cultivars most likely due to their different polyphenol profiles. Analysis of the distribution of polyphenols in the cortex and pith of strawberries showed that polyphenols were mostly concentrated in the cortex of the fruit and that the concentration of individual polyphenol in each fruit tissue varied by cultivar. These results indicate that the oxidative stress response varies in each of the strawberry cultivars studied contributing to their unique polyphenolic profile. Results from this study can ultimately help to identify the polyphenols and enzymes related to superior postharvest quality in future studies.
Author:
Publisher:
ISBN:
Category : Medicine
Languages : en
Pages : 2520
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Book Description
Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
Author: Hauke Hilz
Publisher:
ISBN: 9789085046240
Category :
Languages : en
Pages : 158
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Book Description
Author: Francisco A . Tomás-Barberán
Publisher: John Wiley & Sons
ISBN: 1119563720
Category : Technology & Engineering
Languages : en
Pages : 560
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Book Description
Presents recent research on metabolism and the health effects of polyphenols Consumer interest in the health benefits of many phenolic compounds found in plant foods and derivatives has grown considerably in recent years, giving rise to an increased demand for functional foods. Although preclinical and observational studies have promoted the protective properties of polyphenols for a range of chronic diseases, evidence has shown that most dietary polyphenols have little bioavailability. Once ingested, most of them are metabolized by either the intestinal enzymes or by the gut microbiota and then undergo extensive phase-II metabolism reaching significant concentrations of conjugated metabolites. They remain in the systemic circulation and target systemic tissues where trigger biological effects. The polyphenol-derived metabolites produced in humans are dependent upon the composition of the gut microbiota and the subject genetics. Thus all the metabolites do not show the same biological activity in different individuals. To fully understand the health effects of polyphenols, further clinical investigations are required. Dietary Polyphenols describes the latest findings on the polyphenol metabolism and reviews the current evidence on their health effects and that of their bioavailable metabolites. Emphasizing the importance of interindividual variability and the critical role of gut microbiota, this authoritative volume features contributions from recognized experts in the field, exploring specific families of extractable and non-extractable phenolic compounds that exhibit potential health effects. Topics include structural diversity of polyphenols and distribution in foods, bioavailability and bioaccessibility of phenolics, metabolism, and gastrointestinal absorption of various metabolites and their health effects. This comprehensive volume: Discusses the bioavailability, bioaccessibility, pharmacokinetics studies, and microbial metabolism of different groups of phenolic compounds Examines the interaction between polyphenols and gut microbiota Describes analytical methods for identifying and quantifying polyphenols in foods and biological samples Reviews recent epidemiological and clinical intervention studies showing protective effects of polyphenols Dietary Polyphenols: Metabolism and Health Effects is an important resource for scientists working in the area of dietary polyphenols and health effects, microbiota, and their interaction with other nutritional compounds, and for health professionals, nutritionists, dieticians, and clinical researchers with interest in the role of polyphenols in the prevention and treatment of chronic diseases.
Author: Olusola Lamikanra
Publisher: CRC Press
ISBN: 1420031872
Category : Technology & Engineering
Languages : en
Pages : 482
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Book Description
A comprehensive reference for the emerging fresh-cut fruits and vegetable industry, Fresh-cut Fruits and Vegetables: Science, Technology and Market focuses on the unique biochemical, physiological, microbiological, and quality changes in fresh-cut processing and storage. It highlights the distinct equipment design, packaging requirements, production economics, and marketing considerations for fresh-cut products. Based on the extensive research in this area during the last 10 years, this reference is the first to cover the complete spectrum of science, technology, and marketing issues related to this field.
Author: Kevin Gould
Publisher: Springer Science & Business Media
ISBN: 0387773355
Category : Science
Languages : en
Pages : 345
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Book Description
In recent years there has been an unprecedented expansion of knowledge about anthocyanins pigments. Indeed, the molecular genetic control of anthocyanins biosynthesis is now one of the best understood of all secondary metabolic pathways. There have also been substantial improvements in analytical technology that have led to the discovery of novel anthocyanin compounds. Armed with this knowledge and the tools for genetic engineering, plant breeders are now introducing vibrant new colors into horticultural crops. The food industry has also benefited from the resurgence of interest in anthocyanins. A greater understanding of the chemistry of these pigments has led to improved methods for stabilizing the color of anthocyanins extracts, so that they are more useful as food colorings. Methods for the bulk production of anthocyanins from cell cultures have been optimized for this purpose. Possible benefits to human health from the ingestion of anthocyanin-rich foods have also been a major feature of the recent scientific literature. Anthocyanins are remarkably potent antioxidants, and their ingestion has been postulated to stave off the effects of oxidative stress. These pigments, especially in conjunction with other flavonoids, have been associated with reductions in the incidence and severity of many other non-infectious diseases, including diabetes, cardiovascular disease and certain cancers. An industry is developing around anthocyanins as nutritional supplements. Finally, there has been significant progress in our understanding of the benefits of anthocyanins to plants themselves. Originally considered an extravagance without a purpose, anthocyanins are now implicated in multifarious vital functions. These include the attraction of pollinators and frugivores, aposematic defense from herbivores, and protection from environmental stressors such as strong light, UVB, drought, and free radical attacks. Anthocyanins are evidently highly versatile, and enormously useful to plants. This book covers all aspects of the biosynthesis and function of anthocyanins (and related compounds such as proanthocyanidins) in plants, and their applications in agriculture, food products, and human health. Featured areas include their relevance to: * Plant stress * Flower and fruit color * Human health * Wine quality and health attributes * Food colorants and ingredients * Cell culture production systems * The pastoral sector
Author: José Justino
Publisher: BoD – Books on Demand
ISBN: 953513423X
Category : Science
Languages : en
Pages : 486
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Book Description
Flavonoids are abundant secondary metabolites found in plants and fungi that have various roles in these organisms, including pigmentation, cell signalling, plant defence and inter-organism communication. Due to their abundance in nature, flavonoids are also important components of the human diet, and the last four decades have seen an intense study focused on the structure characterization of flavonoids and on their roles in mammal metabolism. This book reviews most of the well-established activities of flavonoids, and we also present more recent research studies on the area of flavonoids, including the chemical aspects of structure characterization of flavonoids, the biosynthesis of flavonoids in model plants as well as their role in abiotic stress situations and in agriculture, the role of flavonoids in metabolism and health and their importance in foods, from consumption to their use as bioactive components.
