Browsing by Subject "Carotenoid"

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Eco-physiological studies on False Horn plantain
(2020) Dzomeku, Beloved Mensah; Wünsche, Jens Norbert
West Africa suffers from climate uncertainty, high levels of variability, lack of access to real-time and future climate information, and poor predictive capacity are common barriers to adaptation though the region is identified as climate-change hotspot. The regions vulnerability is heightened by its overdependence on rain-fed agriculture, with its sensitivity to climate change and variability. Rain-fed agriculture contributes 30% of GDP and employs about 70% of the population, and it is the main safety net of the rural poor. Drought affects plantain production in West Africa resulting in high level of food insecurity among the vulnerable. Under rain-fed production, achievable yield of plantain landraces are 11.0t/ha while the potential yield is 20t/ha. Plantain breeding is limited due to the complex nature of the breeding process. Plantain plant itself is a giant herbaceous plant occupying 6m2 of land hence only 1667 could occupy a hectare of land. The production system is faced with a myriad of challenges from inadequate healthy planting materials at the time of plantain through the production system to post-harvest. Unlike bananas which are mainly produce by multinational companies under irrigation, plantain production is mainly by smallholder farmers under rain-fed agriculture. Whereas banana production under irrigation is efficient, plantain production under rainfed production is haphazard and unsustainable. Farm sizes range between 0.4 to 5ha. Major limiting factors of the rainfed system is drought resulting in low yields and economic loses. Our study seeks to understand the effects of drought on the physiological responses of plantain crop under rainfed production. Different experiments were conducted to study the responses of various cultivars to on-farm rapid production of healthy planting materials. The results revealed that drought seriously affects natural regeneration of plantain planting materials as such new approaches need to be used for sufficient production. As each plantain plant produces averagely 42 leaves before flowering and each leaf has at least one axillary bud, it presupposes that 42 suckers should be produced at harvest. However, at harvest only 12 healthy suckers are produced around each plantain plant. The approach is able to exploit the full potential of every sucker to generate healthy planting materials. This technique therefore could be used to set up commercial propagation system for plantain planting material production. The study revealed Apantu and hybrid plantain FHIA-21 to show same responses. Plantain farmers can easily produce in large quantities healthy plantain planting materials using sawdust and building their own humidity chambers near water source. The study also showed that there is the potential for farmers to use this technique for establishing commercial propagation centres to generate healthy planting materials. We also studied the physiological responses of Apantu crop to water regimes and natural mycorrhization of plantains. Also, study was conducted on the fruit maturity index and the effect of climate variability on fruit micronutrient content. The natural mycorrhization of plantain roots was the first to be reported on plantain in Ghana. During the study it was observed that plantain roots were naturally colonised by mycorrhizae. However, this phenomenon was cultivar specific; with Apantu roots more colonised compared to Apem. Sustainable intensification of plantain production could be achieved through the use of beneficial soil microbes in production. Conventional production systems, however, do not promote the survival of these microbes. The study further revealed that plantains respond to water stress by reduction in stomatal density, movement and reduction in leaf area. In addition, early stages of water stress had little effect on the final yield of the crop. The anatomical and physiological studies were challenges faced in laticiferous plant like the plantain. However, drought stress at advance stage of growth of plantain adversely affect yields. Our study also showed that fruit maturity index could vary with seasons. The various maturity indices used in plantain production could not be used under rain-fed conditions; especially angularity. The angularity index used was observed not to be appropriate in the dry season. The study also revealed high α-carotene levels with seasonality and maturity in plantain. The high levels of provitamin A in plantain fruits during the dry season coincided with high incidence of sun’s UV index. This finding could play a significant role in the plantain industry as a food security crop the vulnerable who could not afford the high provitamin A foods especially for children under five years. However, the retention and bioavailability of the carotenoid after cooking need to be studied. In conclusion all the chapters showed clear understanding of the behaviour of plantain under severe adverse environmental conditions and conclusions drawn to guide future production of the crop. Under climate change with its complexities, further studies on plantain is needed to improve productivity to achieve food security in West Africa.
Einfluss von Karotten- und Tomatensaft-Konsum auf Coloncarcinogenese-relevante Faecesmarker beim Menschen
(2006) Schnäbele, Kerstin; Briviba, Karlis
Colorectal cancer is one of the most common tumor diseases in the world. Most of the colorectal tumors are sporadic and develop somatically in epithelial cells. Nutritional factors can markedly affect tumor development. A high intake of fruits and vegetables is often associated with a reduced risk of colorectal cancer. Protective effects of fruits and vegetables are attributed to ingredients, such as fibers, vitamins, and secondary plant products (e.g. carotenoids), which have potential anticarcinogenic properties. The aim of this study was to investigate, by means of a human intervention trial with carrot and tomato juice consumption, whether a diet rich in carotenoids, especially high in beta-carotene and lycopene, can modify processes relevant to colon carcinogenesis in the gastrointestinal lumen. Therefore, several faecal markers had to be established and used in this study. In the randomized crossover trial, 22 healthy male subjects on a low-carotenoid diet consumed 330ml of carrot or tomato juice daily for a period of two weeks. The two juice intervention periods were preceded by two-week depletion phases. At the end of each study period the stool of twelve volunteers was collected over a 48-hour period. This stool was used to produce some preparations such as non-filtered and sterile-filtered faecal water, as well as faecal lipid extracts, in order to use them in cell culture systems. Spectral photometric and flow cytometric methods were used to determine the effects of the above-mentioned preparations on colon adenocarcinoma cells (HT-29), as well as to determine the activities of the bacterial enzymes beta- glucosidase and beta-glucuronidase in faecal water. HPLC methods were used to measure the concentrations of several bile acids in faecal water, as well as to determine the concentrations of carote-noids and malondialdehyde (MDA) in faecal samples. The concentrations of the major short chain fatty acids (SCFA) were measured via gas chromatography. Consumption of carrot juice led to a marked increase of beta-carotene and alpha-carotene in faeces and in non-filtered faecal water, as did lycopene after consumption of tomato juice. In the succeeding depletion phases, the contents of those carotenoids in faeces and faecal water returned to their initial values. Changes in faecal MDA concentrations by carrot and tomato juice interventions could not be observed. Faecal water showed high, dose-dependent cytotoxic effects on HT-29 cells. Those effects were, however, not markedly changed by carrot and tomato juice consumption. Neither bile acid concentrations nor the bile acid profile in faecal water changed after carrot and tomato juice consumption. Bacterial activities of beta-glucosidase and beta-glucuronidase also did not change. While tomato juice consumption did not significantly affect the pH value of faecal water, this value was, however, decreased by carrot juice consumption. Although faecal water concentrations of acetate and butyrate contributed to the decrease in faecal water pH values, SCFA were probably not responsible for the observed pH changes after carrot juice consumption. SCFA concentrations in faecal water and SCFA proportions did not change significantly. Neither bile and SCFA concentrations, nor the activities of tested bacterial enzymes, had any influence on the cytotoxic effects of sterile-filtered faecal water. These cytotoxic effects, however, decreased with increasing proportions of the primary bile acids cholic and chenodesoxycholic acid, independent of the study phases. As determined by multiple regression analysis, the most probable leading factors for the growth inhibitory effects of faecal water are the faecal MDA content and bacterial beta-glucosidase activity. Further studies should investigate whether the parameters mentioned directly influence cytotoxic and antiproliferative effects of faecal water or if those parameters are indirect markers for the activity of individual microflora. Carrot and tomato juice consumption strongly increased the cytotoxic effects of faecal lipid extracts in HT-29 cells, likely caused by the induction of apoptosis. Which mechanisms account for these effects and the consequences of these effects in the in vivo situation should be investigated in further studies. This work shows that two-week interventions with carotenoid-rich juices lead only to minor changes in luminal processes relevant to colon carcinogenesis in young healthy volunteers on an energy- and macronutrient-balanced diet. Lacking effects on 1) the toxic and antiproliferative properties of faecal water, 2) lipid peroxidation in faeces, 3) the bile and SCFA concentrations in faecal water, and 4) bacterial enzyme activities indicate that related physiological effects can not be influenced by a diet rich in carotenoids under the just described conditions. Other anticarcinogenic mechanisms seem to be of greater importance.
Feasibility of microbial biodiesel and carotenoid production considering the potential of food processing wastewaters as low cost carbon sources using the example of red yeast Rhodotorula glutinis
(2013) Braunwald, Teresa; Claupein, Wilhelm
Due to the increasing demand for sustainable biofuels, microbial oils as feedstock for the transesterification into biodiesel have gained scientific and commercial interest. Also microbial carotenoids have a considerable market potential as natural colorants. Against this background this thesis assessed the feasibility of biodiesel produced by heterotrophic microorganisms, particularly yeasts, using the example of oleaginous red yeast Rhodotorula glutinis. To improve the economic efficiency of this process, several studies have been conducted in order to test (i) whether wastewaters from the agricultural processing industry can be utilized as low-cost carbon and nutrient source for growth and lipid production by R. glutinis and (ii) if they also facilitate the simultaneous production of beta-carotene and other carotenoids as high-value by-products. It has been shown at a small scale, that agricultural processing wastewaters can be used as feedstock for the microbial production of lipids and carotenoids. The general discussion continues to assess the approach of microbial biodiesel production in a broader context in terms of its economic, environmental and energetic performance. The calculated break-even price of microbial oil, excluding the cost of the carbon source for fermentation, is around double the price of conventional plant oils as competing products. To reduce the costs, cultivation in open raceway ponds was proposed, which led to a cost reduction of around 20 %. In order to assess the potential environmental benefits different life cycle assessments from algae biodiesel production, which share common features with the proposed process, have been analyzed. It was concluded, that microbial biodiesel cannot outperform common 1st generation biodiesel in terms of GHG emissions, whereas factors of eutrophication potential and land competition could be significantly improved. The high climate relevant emissions were mainly driven by the high energy requirements connected to the extraction of microbial oil, which also puts a heavy burden on the energetic efficiency of the process. Considering the potential of continued research and technical development along with the political commitment to promote 2nd and 3rd generation biofuels, it was concluded, that in the long term microbial biodiesel could become a commercial reality above laboratory and pilot scale. Due to the different restrictions this will probably not happen within the next 20-30 years. Contrary to biodiesel, carotenoids are high-value products, with beta-carotene yielding around US$ 600 per kg. Sustained by this high price and allowing for certain improvements regarding beta-carotene yields and extraction techniques, it can be possible to economically and sustainable produce beta-carotene from R. glutinis in the near future.
The influence of phosphate-availability and phytic acid on the profiles of fatty acids, (poly)phenols, carotenoids, and tocochromanols in maize (Zea mays L.) grains – from field experiments to human in vitro digestion studies
(2022) Lux, Peter Erwin; Frank, Jan
Phosphorus (P) is an essential element for living organisms and involved in phosphorylation reactions, including the biosynthesis of several organic micronutrients. Since P is taken up by plants from soil as phosphates, phosphate fertilizers are applied on fields to support the P-supply for crops. Today, shrinking global P-resources demand a reduction in the application of P-containing fertilizers, but knowledge about possible effects of a reduced phosphate-availability in soils on the quality of maize grains is lacking. Thus, it was hypothesized that a reduced phosphate-availability in soil influences the concentrations of dietary organic compounds (phenolics, fatty acids, carotenoids, and tocochromanols) in grains of maize during cultivation. Moreover, concentration differences in the P-storage form phytic acid in maize grains may impact the oxidative stability of these organic compounds during processing and digestion. Fertilizer experiments with maize hybrids were conducted at study sites with low to high phosphate concentrations in soil (1.6 to 20.6 mg CAL-P/100 g soil) in Germany. GC-MS or HPLC-(MS) analyses of the ground maize grains revealed the identity of fatty acids, insoluble (mostly diferulic and triferulic acids) and soluble (poly)phenols, carotenoids, and tocochromanols. The concentrations of these (poly)phenols, carotenoids, and tocochromanols as well as the fatty acid composition in the grains of the maize plants grown with or without phosphate fertilizer were not significantly (p < 0.05) different. Interaction effects between phosphate application and the locations on the fatty acid composition as well as on carotenoids and tocochromanols were considered as insignificant, concluding that a reduction in phosphate fertilization could be implemented on most fields in Germany when only considering these dietary compounds. Lastly, the influence of phytic acid on oxidation processes in maize during processing of porridge and in vitro digestion was examined. Porridges were prepared from maize flour containing either high phytic acid concentration or low phytic acid concentration supplemented with or without phytate. The porridges were digested using a human in vitro digestion model, resulting in a decrease in tocochromanols, carotenoids and unsaturated fatty acids. Oxidation products (alpha-tocopherylquinone, malondialdehyde) were formed in all samples, implying that phytic acid addition did not show the expected protective effect. The addition of phytate evoked a significant reduction in the micellarization efficiency of most carotenoids. Thus, the knowledge about phytic acid as antinutrient was extended.