Andean indigenous food crops: nutritional value and bioactive compounds

The Andean area of South America is a very important center for the domestication of food crops. This area is the botanical origin of potato, peanut and tomato. Less well- known crops, such as quinoa (Chenopodium quinoa), kañiwa (Chenopodium pallidicaule) and kiwicha (Amaranthus caudatus), were also domesticated by ancient Andean farmers. These crops have a long history of safe use with the local populations and they have contributed to the nutrition and wellbeing of the people for centuries. Several studies have reported the nutritional value of Andean grains. They contain proteins with a balanced essential amino acid composition that are of high biological value, good quality oil and essential minerals, for example iron, calcium and zinc. They are potential sources of bioactive compounds such as polyphenols and dietary fiber. The main objective of the practical work was to assess the nutritional value of Andean native grains with a special emphasis on the bioactive components and the impact of processing. The compounds studied were phenolic acids, flavonoids, betalains and dietary fiber. The radical scavenging activity was measured as well. Iron, calcium and zinc content and their bioavailability were analyzed as well. The grains were processed by extrusion with the aim to study the effect of processing on the chemical composition. Quinoa, kañiwa and kiwicha are very good sources of dietary fiber, especially of insoluble dietary fiber. The phenolic acid content in Andean crops was low compared with common cereals like wheat and rye, but was similar to levels found in oat, barley, corn and rice. The flavonoid content of quinoa and kañiwa was exceptionally high. Kiwicha did not contain quantifiable amounts of these compounds. Only one variety of kiwicha contained low amounts of betalains. These compounds were not detected in kañiwa or quinoa. Quinoa, kañiwa and kiwicha are good sources of minerals. Their calcium, zinc and iron content are higher than the content of these minerals in common cereals. In general, roasting did not affect significantly mineral bioavailability. On the contrary, in cooked grains, there was an increase in bioavailability of zinc and, in the case of kañiwa, also in iron and calcium bioavailability. In all cases, the contents of total and insoluble dietary fiber decreased during the extrusion process. At the same time, the content of soluble dietary fiber increased. The content of total phenolics, phytic acid and the antioxidant activity decreased in kiwicha varieties during the extrusion process. In the case of quinoa, the content of total phenolic compounds and the radical scavenging activity increased during the extrusion process in all varieties. Taken together, the studies presented here demonstrate that the Andean indigenous crops have excellent potential as sources of minerals, flavonoids and dietary fiber. Further studies should be conducted to characterize the phenolic compound and antioxidant composition in processed grains and end products. Quinoa, kañiwa and kiwicha grains are consumed widely in Andean countries but they also have a significant, worldwide potential as a new cultivated crop species and as an imported commodity from South America. Their inclusion in the diet has the potential to improve the intake of minerals and health-promoting bioactive compounds. They may also be interesting raw materials for special dietary foods and functional foods offering natural sources of specific health-promoting components.

Cuticular and Suberin Polymers of Edible Plants. Analysis by Gas Chromatographic-Mass Spectrometric and Solid State Spectroscopic Methods

Cutin and suberin are structural and protective polymers of plant surfaces. The epidermal cells of the aerial parts of plants are covered with an extracellular cuticular layer, which consists of polyester cutin, highly resistant cutan, cuticular waxes and polysaccharides which link the layer to the epidermal cells. A similar protective layer is formed by a polyaromatic-polyaliphatic biopolymer suberin, which is present particularly in the cell walls of the phellem layer of periderm of the underground parts of plants (e.g. roots and tubers) and the bark of trees. In addition, suberization is also a major factor in wound healing and wound periderm formation regardless of the plants’ tissue. Knowledge of the composition and functions of cuticular and suberin polymers is important for understanding the physiological properties for the plants and for nutritional quality when these plants are consumed as foods. The aims of the practical work were to assess the chemical composition of cuticular polymers of several northern berries and seeds and suberin of two varieties of potatoes. Cutin and suberin were studied as isolated polymers and further after depolymerization as soluble monomers and solid residues. Chemical and enzymatic depolymerization techniques were compared and a new chemical depolymerization method was developed. Gas chromatographic analysis with mass spectrometric detection (GC-MS) was used to assess the monomer compositions. Polymer investigations were conducted with solid state carbon-13 cross polarization magic angle spinning nuclear magnetic resonance spectroscopy (13C CP-MAS NMR), Fourier transform infrared spectroscopy (FTIR) and microscopic analysis. Furthermore, the development of suberin over one year of post-harvest storage was investigated and the cuticular layers from berries grown in the North and South of Finland were compared. The results show that the amounts of isolated cuticular layers and cutin monomers, as well as monomeric compositions vary greatly between the berries. The monomer composition of seeds was found to differ from the corresponding berry peel monomers. The berry cutin monomers were composed mostly of long-chain aliphatic ω-hydroxy acids, with various mid-chain functionalities (double-bonds, epoxy, hydroxy and keto groups). Substituted α,ω-diacids predominated over ω-hydroxy acids in potato suberin monomers and slight differences were found between the varieties. The newly-developed closed tube chemical method was found to be suitable for cutin and suberin analysis and preferred over the solvent-consuming and laborious reflux method. Enzymatic hydrolysis with cutinase was less effective than chemical methanolysis and showed specificity towards α,ω-diacid bonds. According to ₁₃C CP-MAS NMR and FTIR, the depolymerization residues contained significant amounts of aromatic structures, polysaccharides and possible cutan-type aliphatic moieties. Cultivation location seems to have effect on cuticular composition. The materials studied contained significant amounts of different types of biopolymers that could be utilized for several purposes with or without further processing. The importance of the so-called waste material from industrial processes of berries and potatoes as a source of either dietary fiber or specialty chemicals should be further investigated in detail. The evident impact of cuticular and suberin polymers, among other fiber components, on human health should be investigated in clinical trials. These by-product materials may be used as value-added fiber fractions in the food industry and as raw materials for specialty chemicals such as lubricants and emulsifiers, or as building blocks for novel polymers.

Diet and Probiotics during Pregnancy - Endorsing developmental Programming

Maternal obesity has been shown to increase the risk for adverse reproductive health outcomes such as gestational diabetes, hypertension, and preeclampsia. Moreover, several studies have indicated that overnutrition and maternal obesity adversely program the development of offspring by predisposing them to obesity and other chronic diseases later in life. The exact molecular mechanisms leading to developmental programming are not known, but it has recently been suggested that obesity-related low-grade inflammation, gut microbiota and epigenetic gene regulation (in particularly DNA methylation) participate in the developmental programming phenomenon. The aim of this thesis was to evaluate the effect of diet, dietary counseling and probiotic intervention during pregnancy in endorsing favorable developmental programming. The study population consisted of 256 mother-child pairs participating in a prospective, double-blinded dietary counselling and probiotic intervention (Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12) NAMI (Nutrition, Allergy, Mucosal immunology and Intestinal microbiota) study. Further overweight women were recruited from maternal welfare clinics in the area of Southwest Finland and from the prenatal outpatient clinic at Turku University Hospital. Dietary counseling was aimed to modify women’s dietary intake to comply with the recommended intake for pregnant women. Specifically, counseling aimed to affect the type of fat consumed and to increase the amount of fiber in the women’s diets. Leptin concentration was used as a marker for obesity-related low-grade inflammation, antioxidant vitamin status as an efficiency marker for dietary counselling and epigenetic DNA methylation of obesity related genes as a marker for probiotics influence. Results revealed that dietary intake may modify obesity-associated low-grade inflammation as measured by serum leptin concentration. Specifically, dietary fiber intake may lower leptin concentration in women, whereas the intakes of saturated fatty acids and sucrose have an opposite effect. Neither dietary counselling nor probiotic intervention modified leptin concentration in women, but probiotics tended to increase children’s leptin concentration. Dietary counseling was an efficient tool for improving antioxidant vitamin intake in women, which was reflected in the breast milk vitamin concentration. Probiotic intervention affected DNA methylation of dozens of obesity and weight gain related genes both in women and their children. Altogether these results indicate that dietary components, dietary counseling and probiotic supplementation during pregnancy may modify the intrauterine environment towards favorable developmental programming.

Early nutritional determinants in cardio-metabolic programming – A prospective randomized controlled dietary intervention study

Western societies have been faced with the fact that overweight, impaired glucose regulation and elevated blood pressure are already prevalent in pediatric populations. This will inevitably mean an increase in later manifestations of cardio-metabolic diseases. The dilemma has been suggested to stem from fetal life and it is surmised that the early nutritional environment plays an important role in the process called programming. The aim of the present study was to characterize early nutritional determinants associating with cardio-metabolic risk factors in fetuses, infants and children. Further, the study was designated to establish whether dietary counseling initiated in early pregnancy can modify this cascade. Healthy mother-child pairs (n=256) participating in a dietary intervention study were followed from early pregnancy to childhood. The intervention included detailed dietary counseling by a nutritionist targeting saturated fat intake in excess of recommendations and fiber consumption below recommendations. Cardio-metabolic programming was studied by characterizing the offspring’s cardio-metabolic risk factors such as over-activation of the autonomic nervous system, elevated blood pressure and adverse metabolic status (e.g. serum high split proinsulin concentration). Fetal cardiac sympathovagal activation was measured during labor. Postnatally, children’s blood pressure was measured at six-month and four-year follow-up visits. Further, infants’ metabolic status was assessed by means of growth and serum biomarkers (32-33 split proinsulin, leptin and adiponectin) at the age of six months. This study proved that fetal cardiac sympathovagal activity was positively associated with maternal pre-pregnancy body mass index indicating adverse cardio-metabolic programming in the offspring. Further, a reduced risk of high split proinsulin in infancy and lower blood pressure in childhood were found in those offspring whose mothers’ weight gain and amount and type of fats in the diet during pregnancy were as recommended. Of note, maternal dietary counseling from early pregnancy onwards could ameliorate the offspring’s metabolic status by reducing the risk of high split proinsulin concentration, although it had no effect on the other cardio-metabolic markers in the offspring. At postnatal period breastfeeding proved to entail benefits in cardio-metabolic programming. Finally, the recommended dietary protein and total fat content in the child’s diet were important nutritional determinants reducing blood pressure at the age of four years. The intrauterine and immediate postnatal period comprise a window of opportunity for interventions aiming to reduce the risk of cardio-metabolic disorders and brings the prospect of achieving health benefits over one generation.

Carbohydrate intake in children - associations with dietary intakes, growth, serum lipids,and dental health. The STRIP Project

This study is part of the STRIP study, which is a long-term, randomized controlled trial, designed to decrease the exposure of children in the intervention group (n=540) to known risk factors of atherosclerosis. The main focus of the intervention was the quality of dietary fat. The control group (n=522) did not receive any individualized counselling. Food consumption was evaluated with food records, and blood samples were drawn and growth was measured regularly for all participating children from 13 months to 9 years. A subsample of 66 children participated in a dental health survey. The number of studies on children’s carbohydrate intake, especially fibre intake, is insufficient. The current international recommendations for fibre intake in children are based on average assumptions and data extrapolated from intakes in adults and intake recommendations for adults. Finnish nutrition recommendations lack strict recommendations for dietary fibre in children. Due to fibre’s high bulk volume, excessive dietary fibre is considered to decrease energy density and hence it may have an adverse effect on growth. If fats are reduced from the diet, the low-fat diet may become high in sucrose. Therefore, especially in the STRIP study, it is important to determine the use of fibre and sucrose in children and possible associations with growth and nutrition as well as dental health. The results of the present study indicate that a high fibre intake does not displace energy or disturb growth in children and that children with high fibre intake have better quality of diet than those with low fibre intake. Additionally, dietary fibre intake associated inversely with serum cholesterol concentration. Other carbohydrates also affected serum lipid levels as well, since total carbohydrates, sucrose, and fructose increased serum triglyceride concentration. Total carbohydrate intake reduced HDL cholesterol concentration only in children with apoE3 or apoE4 phenotype. Over the period from the 1970s to the 1990s the dental health of children in Finland has substantially improved despite an increase in sucrose intake. The improvement was thought to be due to improved dental hygiene and the use of fluorine. However, during the past twenty years improvement in dental health has stopped. The present study showed that high long-term sugar intake increases risk of caries in children. High intake of sugar had also negative effects on the diet of children, because it worsens dietary quality by displacing essential nutrients. Furthermore, the quality of dietary fat was worse in children with high sucrose intake. In this study the children’s high sucrose intake was not associated with overweight, but interestingly, it associated inversely with growth.

Development of porous glass-fiber reinforced composite for bone implants. Evaluation of antimicrobial effect and implant fixation

Cranial bone reconstructions are necessary for correcting large skull bone defects due to trauma, tumors, infections and craniotomies. Traditional synthetic implant materials include solid or mesh titanium, various plastics and ceramics. Recently, biostable glass-fiber reinforced composites (FRC), which are based on bifunctional methacrylate resin, were introduced as novel implant solution. FRCs were originally developed and clinically used in dental applications. As a result of further in vitro and in vivo testing, these composites were also approved for clinical use in cranial surgery. To date, reconstructions of large bone defects were performed in 35 patients. This thesis is dedicated to the development of a novel FRC-based implant for cranial reconstructions. The proposed multi-component implant consists of three main parts: (i) porous FRC structure; (ii) bioactive glass granules embedded between FRC layers and (iii) a silver-polysaccharide nanocomposite coating. The porosity of the FRC structure should allow bone ingrowth. Bioactive glass as an osteopromotive material is expected to stimulate the formation of new bone. The polysaccharide coating is expected to prevent bacterial colonization of the implant. The FRC implants developed in this study are based on the porous network of randomly-oriented E-glass fibers bound together by non-resorbable photopolymerizable methacrylate resin. These structures had a total porosity of 10–70 volume %, of which > 70% were open pores. The pore sizes > 100 μm were in the biologically-relevant range (50-400 μm), which is essential for vascularization and bone ingrowth. Bone ingrowth into these structures was simulated by imbedding of porous FRC specimens in gypsum. Results of push-out tests indicated the increase in the shear strength and fracture toughness of the interface with the increase in the total porosity of FRC specimens. The osteopromotive effect of bioactive glass is based on its dissolution in the physiological environment. Here, calcium and phosphate ions, released from the glass, precipitated on the glass surface and its proximity (the FRC) and formed bone-like apatite. The biomineralization of the FRC structure, due to the bioactive glass reactions, was studied in Simulated Body Fluid (SBF) in static and dynamic conditions. An antimicrobial, non-cytotoxic polysaccharide coating, containing silver nanoparticles, was obtained through strong electrostatic interactions with the surface of FRC. In in vitro conditions the lactose-modified chitosan (chitlac) coating showed no signs of degradation within seven days of exposure to lysozyme or one day to hydrogen peroxide (H2O2). The antimicrobial efficacy of the coating was tested against Staphylococcus aureus and Pseudomonas aeruginosa. The contact-active coating had an excellent short time antimicrobial effect. The coating neither affected the initial adhesion of microorganisms to the implant surface nor the biofilm formation after 24 h and 72 h of incubation. Silver ions released to the aqueous environment led to a reduction of bacterial growth in the culture medium.

Effect of ultrastructural features on mechanical properties of softwood fiber

The main objective of this study was to develop mathematical model capable to describe the effect of ultrastructural features on the longitudinal modulus of elasticity of softwood fiber. Another objective was to identify, based on ultrastructural features, a potential explanatory factor for the mechanical difference between Norway spruce and Scots pine fibers and to demonstrate its influence utilizing developed modelling tools. According to the literature, the main difference between the pine and spruce fibers is the pit structure, which is clearly different in these fibers. The spruce fiber contains a lot of tiny pits, whereas the pits of the pine fiber are larger and the total number of them is smaller. The effect of the pits on the longitudinal modulus of elasticity of fiber is studied with both the analytical and the numerical model. The results show that, although the spruce fiber seems to contain clearly more pits, larger pits appearing in the pine fiber turn out to have a stronger influence on the longitudinal modulus of elasticity of the fiber. The effect of local variation of microfibril angle which occurs near the pits seems to be minor. Moreover, the results suggest that spruce fibers may have higher ultimate strength due to the more uniform straining behavior.