Is contextual-potentiated eating dependent on caloric density of food?

One experiment tested whether a specific context could elicit eating in rats as a result of Pavlovian conditioning and whether this effect depended on the caloric density of food. Thirty two deprived rats experienced two contexts. They had access to food in context A, but no food was available in context B. During conditioning, half of the animals received high density caloric food (HD groups) whereas the other half, low density caloric food (LD groups). Then, half of the rats in each type of food group was tested in context A and the other half in context B. The results demonstrated an effect of context conditioning only in HD groups. These findings suggest the relevance of both contextual conditioning and caloric density of food in eating behaviour. Implications for the aetiology of binge eating will be discussed.

Determination of aluminum in food samples after preconcentration as aluminon complex on microcrystalline naphthalene by spectrophotometry

A sensitive preconcentration procedure for spectrophotometeric determination of aluminum was developed. Aluminum as aluminon complex is adsorbed on microcrystalline naphthalene. The naphthalene containing the complex is dissolved in 3 mL of acetone and its absorbance is measured at 544 nm. The effect of various factors on the preconcentration of aluminum was investigated. The calibration graph was linear in the range of 1-60 mg L-1. The limit of detection was 0.52 mg L-1 and relative standard deviation for the determination of 5 mg L-1 was 2.65%. The proposed solid phase extraction procedure was applied to determination of aluminum in food samples.

Sensory and Non-sensory Factors Behind the Liking and Choice of Healthy Food Products

A healthy and balanced diet can reduce health problems, such as overweight and metabolic syndrome. In general, people have a considerably good knowledge of what constitutes a healthy diet and how they could achieve it with their food choices. Besides, people argue that health is among their top five food choice motives. Nevertheless, the prevalence of overweight is increasing and other food choice motives, such as taste, seem to conflict with the health. Liking for food does not necessarily determine acceptance alone, thus several non-sensory factors, such as brand, country of origin and nutrition claim, can also influence. Moreover, consumers are individuals in how they prioritize sensory and nonsensory factors of foods, but e.g. increasing age, female gender and health concern have been connected to a more health-oriented dietary behaviour. To sum up, identifying different factors that can increase the liking and consumption of healthy food is essential in order to develop more attractive healthful food products. Adding vitamins, minerals, fibre or other ingredients to a food product can be used to enrich the nutritional quality of the products. However, this may be difficult in practice as regards the sensory quality and pleasantness of the foods. Generally, consumers are not willing to compromise on taste in food. On the other hand, consumers are very heterogeneous in their likings, and their personal values and attitudes may interact with preferences for specific sensory characteristics. The aims of this study were to investigate the effects of intrinsic product characteristics on sensory properties and hedonic responses; to determine the impact of few non-sensory factors; and to examine the interaction between sensory and non-sensory factors with consumers’ demographics, values and attitudes in liking of healthy model foods. The results showed that product composition influenced sensory quality and had an effect on hedonic responses. Adding flaxseed to bakery products showed a significant improvement in the nutritional quality without negative effects on sensory properties. On the other hand, the fortification of wellness beverages with vitamins and minerals may impart off-flavours. In general, sweetness of yoghurts, freshness of wellness beverages and low intensity of rye bread flavour appealed to consumers. Information about the domestic origin of yoghurts and claiming a specific function for wellness beverages enhanced liking. However, consumers who were more concerned about their health and considered natural content as an important food choice motive, rated sourer and less sweet yoghurts and wellness beverages as more pleasant. In addition, interest in health increased the consumption of rye breads and other whole grain breads among adolescents. The results showed that the optimal product quality in terms of intrinsic and extrinsic factors differs between individual consumers, and personal values and food choice motives can be connected to preferences for specific sensory characteristics of foods. This indicates that each food product needs to be considered in relation to its specific market niche, and to which segment of consumer will respond most positively to its characteristics.

Foodstuffs and medicines as legal categories in the EU and China. Functional foods as a borderline case

The thesis discusses the regulation of foodstuffs and medicines, and particularly the regulation of functional foods. Legal systems investigated are the EU and China. Both are members of the WTO and Codex Alimentarius, which binds European and Chinese rules together. The study uses three Chinese berries as case examples of how product development faces regulation in practice. The berries have traditional uses as herbal medicines. Europe and China have similar nutrition problems to be resolved, such as obesity, cardiovascular disease, and diabetes. The three berries might be suitable raw materials for functional foods. Consumer products with health-enhancing functions, such as lowering blood pressure, might legally be classifi ed either as foodstuffs or medicines. The classifi cation will depend on functions and presentation of the product. In our opinion, food and medicine regulation should come closer together so the classifi cation issue would no longer be an issue. Safety of both foodstuffs and medicines is strictly regulated. With medicines, safety is a more relative concept, where benefi ts of the product are compared to side-effects in thorough scientifi c tests and trials. Foods, on the other hand, are not allowed to have side-effects. Hygiene rules and rules on the use of chemicals apply. In China, food safety is currently at focus as China has had several severe food scandals. Newly developed foods are called novel foods, and are specifi cally regulated. The current European novel food regulation from 1997 treats traditional third country products as novel. The Chinese regulation of 2007 also defi nes novel foods as something unfamiliar to a Chinese consumer. The concepts of novel food thus serve a protectionist purpose. As regards marketing, foods are allowed to bear health claims, whereas medicines bear medicinal claims. The separation is legally strict: foods are not to be presented as having medicinal functions. European nutrition and health claim regulation exists since 2006. China also has its regulation on health foods, listing the permitted claims and how to substantiate them. Health claims are allowed only on health foods. The European rules on medicines include separate categories for herbal medicines, traditional herbal medicines, and homeopathic medicines, where there are differing requirements for scientifi c substantiation. The scientifi c and political grounds for the separate categories provoke criticism. At surface, the Chinese legal system seems similar to the European one. To facilitate trade, China has enacted modern laws. Laws are needed as the country moves from planned economy to market economy: ‘rule of law’ needs to replace ‘rule of man’. Instead of being citizens, Chinese people long were subordinates to the Emperor. Confucius himself advised to avoid confl ict. Still, Chinese people do not and cannot always trust the legal system, as laws are enforced in an inconsistent manner, and courts are weak. In China, there have been problems with confl icting national and local laws. In Europe, the competence of the EU vs. the competence of the Member States is still not resolved, even though the European Commission often states that free trade requires harmonisation. Food and medicine regulation is created by international organisations, food and medicine control agencies, standards agencies, companies and their organisations. Regulation can be divided in ‘hard law’ and ‘soft law’. One might claim that hard law is in crisis, as soft law is gaining importance. If law is out of fashion, regulation certainly isn’t. In the future, ‘law’ might mean a process where rules and incentives are created by states, NGOs, companies, consumers, and other stakeholders. ‘Law’ might thus refer to a constant negotiation between public and private actors. Legal principles such as transparency, equal treatment, and the right to be heard would still be important.

BimTwin - Two component continuous process hygiene concept

The aim of this study was to examine suitability of BimTwin cleaning concept in card board machine to control microbiological activity and describe microbiological balance of the machine. In a review of literature is examined microbe and spore caused problems in paper industry. Biggest problems are deposits, which decrease runnability and cause quality errors. In this chapter is also introduced most common oxidizing biocides used in paper industry and described ATP assay as a microbiological monitoring method. In an experimental part are included BimTwin mill trial results, chemical condition monitoring methods and microbiological balance in a card board machine. In a second part are examined possibilities to effect hygiene of card board by chemical treatment of the surface size and coating. Result showed that BimTwin concept is suitable for card board machine as a cleaning concept, when chemical dosing is fitted right. For proper dosing and secure tolerable hygiene level, chemical and microbiological monitoring is significant. Determining of the microbiological balance would have need more sampling. According to acquired results, broke turned out to be the biggest microbe source. Sizing and coating experiments showed that it is possible to improve hygiene of card board by chemically treated surface size and coating color.

Integration of the Food Waste Disposer Unit to the Existing Sewage System

Among the numerous approaches to food waste treatment, the food waste disposers method (FWDs), as a newcomer, has become slowly accepted by the general public owing to the worries about its impact on the existing sewage system. This paper aims to justify the role of FWDs in the process of urbanization in order to better prepare a city to take good care of the construction of its infrastructure and the solid waste treatment. Both the literatures and the case study help to confirm that FWDs has no negative effects on the wastewater treatment plant and it is also environmental friendly by reducing the greenhouse gas emissions. In the case study, the Lappeenranta waste water treatment plant has been selected in order to figure out the possible changes to a WWTP following the integration of FWDs: the observation shows only minor changes take place in a WWTP, in case of 25% application, like BOD up 7%, TSS up 6% and wastewater flowrate up 6%, an additional sludge production of 200 tons per year and the extra yield of methane up to 10000m3 per year; however, when the utilization rate of FWD is over 75%, BOD, TSS, and wastewater flowrate will experience more significant changes, thus exerting much pressure on the existing WWTP. FWDs can only be used in residential areas or cities equipped with consummate drainage network within the service sphere of WWTP, therefore, the relevant authority or government department should regulate the installation frequency of FWDs, while promoting the accessory application of FWDs. In the meanwhile, WWTP should improve their treatment process in order to expand their capacity for sludge treatment so as to stay in line with the future development of urban waste management.

Interactions between Polyunsaturated Fatty Acids and Probiotics

The prevalence of inflammatory based diseases has increased in industrialized countries over the last decades. For allergic diseases, two primary hypotheses have been proposed to explain this phenomenon, namely the hygiene and dietary evolution based hypothesis. Particularly, the reduced early exposure to microbes and an increase in the amount of polyunsaturated fatty acids (especially n-6 PUFA) in the diet have been discussed. Often, these two factors have been studied independently, even though both factors have been shown to possess potential health benefits and their mode of action to share similar mechanisms. The hypothesis of the present study was that demonstrate that PUFA and probiotics are not separate entities as such but do interact with each other. In the present study, we investigated whether maternal diet and atopic status influence the PUFA composition of breast milk and serum fatty acids of infants, and whether the fatty acid absorption and utilization of infant formula fatty acids is affected by supplementation of infant formula with probiotic bacteria (Lactobacillus GG and Bifidobacterium lactis Bb-12). Moreover, we investigated the mechanisms by which different PUFA influence the physicochemical and functional properties of probiotics as well as functionality of epithelial cells in vitro. We demonstrated a carry-over effect of dietary fatty acids from maternal diet via breast milk into infants’ serum lipid fatty acids. Our data confirmed the previously shown allergy –related PUFA level imbalances, though it did not fully support the impaired desaturation and elongation capacity hypothesis. We also showed that PUFA incorporation into phospholipids of infants was influenced by probiotics in infant formula in a strain dependent manner. Especially,Bifidobacterium lactis Bb-12 in infant formula promoted the utilization of n-3 PUFA. Mechanistically, we demonstrated that probiotics (Lactobacillus GG, Lactobacillus casei Shirota and Lactobacillus bulgaricus) did incorporate and interconvert exogenous free PUFA in the growth medium into bacterial fatty acids strain and PUFA dependently. In general, high concentrations of free PUFA inhibited the growth and mucus adhesion of probiotics, whereas low concentrations of specific long chain PUFA were found to promote the growth and mucus adhesion of Lactobacillus casei Shirota. These effects were paralleled with only minor alterations in hydrophobicity and electron donor – electron acceptor properties of lactobacilli. Furthermore, free PUFA were also demonstrated to alter the adhesion capacity of the intestinal epithelial cells; n-6 PUFA tended to inhibit the Caco-2 adhesion of probiotics, whereas n-3 PUFA had either no or minor effects or even promote the bacterial adhesion (especially Lactobacillus casei Shirota) to PUFA treated Caco-2 cells. The results of this study demonstrate the close and bilateral interactions between dietary PUFA and probiotics. Probiotics were shown to influence the absorption and utilization of dietary PUFA, whereas PUFA were shown to alter the functional properties of both probiotics and mucosal epithelia. These findings suggest that a more thorough understanding of interactions between PUFA and intestinal microbiota is a prerequisite, when the beneficial effects of new functional foods containing probiotics are designed and planned for human intervention studies.

Catalytic transformations of fatty acid derivatives for food, oleochemicals and fuels over carbon supported platinum group metals

Växtoljor som utgör en förnybar naturresurs används som sådana eller i modifierade former i många industriella processer, som är av stor betydelse för vårt vardagliga liv. Växtoljor används i livsmedel, i kemiska och farmaceutiska produkter, i textilindustrin, för framställning av färgämnen och beläggningsmaterial samt som miljövänliga bränslekomponenter. Fetter och oljor hör till de äldsta kemiska komponenterna som utnyttjas av människan. De består huvudsakligen av glycerolestrar och fettsyror. Fetter och oljor har typiskt en kolkedja med kol-koldubbelbindningar samt karboxyl- och estergrupper, som kan genom hydrering eller dekarboxylering konverteras till nyttiga och miljövänliga produkter med hjälp av ädelmetallkatalysatorer. Aktivt kol (C) används som bärare på katalysatorerna. Väteaddition, d.v.s. hydrering av växtoljor har varit föremål för omfattande forskning i över hundra års tid. Hydreringen är en viktig process, för den tillämpas på produktion av fetter och margarin. Omättade fettsyror hydreras traditionellt på nickelbaserade heterogena katalysatorer. Samtidigt med en partiell hydrering av fettsyrorna och fettsyraestrarna som har två dubbelbindningar pågår också isomeringsreaktioner, vilka ger cis- och transisomerer av reaktantmolekylerna. Den största nackdelen med nickelkatalysatorerna är deras giftighet samt bildning av ohälsosamma transisomerer i reaktionsprodukterna. Dessutom deaktiveras nickelkatalysatorn snabbt p.g.a. att nickeltvålar bildas i reaktionsblandningen. Platinabaserade katalysatorer lider däremot inte av dessa begränsningar. Metaller i platinagruppen i det periodiska systemet studerades i detalj för att avslöja kinetiska effekter i hydreringen av cis-metyloleat. Palladium, rutenium, rhodium, platina och iridium användes som katalytiska metaller. Metallhalten på aktivkolbärare var 1 vikt-%. De olika platinametallerna undersöktes för att kartlägga konkurrerande hydrerings- och isomeringsrutter på metallerna. Det visade sig att metallerna i andra raden av det periodiska systemet (Ru, Rh, Pd) är aktivare i isomeringsprocesserna, medan metallerna i tredje raden (Ir, Pt) har en lägre aktivitet. Pd/C valdes bland platinametallerna, för att den är attraktiv ur ekonomisk synvinkel och den är mycket aktiv och selektiv, speciellt jämfört med nickel. Tyngdpunkten i arbetet var utvecklingen av en alternativ, palladiumbaserad hydreringsteknologi som skulle ersätta den traditionella teknologin som är baserad på användningen av nickelkatalysatorer. Palladiumbaserade katalysatorer kan återcirkuleras, de är aktivare och mera resistenta mot syror och de bildar mindre mängder av skadliga transisomerer. För att denna teknologi skall bli ekonomiskt hållbar och konkurrenskraftig, måste den basera sig på de bästa möjliga katalysatorerna, vilket innebär att en optimal kombination av hög aktivitet och selektivitet samt en lång livstid för katalysatorn krävs. Därför inkluderades teknologiska aspekter kraftigt i forskningen. Mycket arbete satsades på design av palladium på en mesoporös kolbärare och undersökning av korrelationerna mellan katalysatorns egenskaper och dess aktivitet i isomeriseringsreaktionerna och i hydreringen av kol-koldubbelbindningarna i reaktantmolekylen. Katalysatorerna karakteriserades med många fysikaliska och kemiska metoder (transmissionselektronmikroskopi (TEM), röntgendiffraktion (XRD), röntgenfotoelektronspektroskopi (XPS), temperaturprogrammerad reduktion (TPR), temperaturprogrammerad desorption (TPD) av kolmonoxid, kemisorption av kolmonoxid, fysisorption av kväve). Temperaturens, vätetryckets och katalysatorkoncentrationens inverkan på fettsyra- och isomersammansättningen hos de hydrerade oljorna bestämdes under kinetiska betingelser, i frånvaro av massöverföringseffekter. Syreavspjälkning genom fullständig dekarboxylering av karboxylgruppen i fettsyramolekylen är det hittills bästa sättet att framställa miljövänlig dieselolja, eftersom linjära paraffiner fås som reaktionsprodukter och en tillsats av dyr vätgas undviks. Deoxygeneringen undersöktes systematiskt på en Pd/C-katalysator (Sibunit) genom att använda mättade fettsyror C16-C20 och C22 som råvara. Produktmolekylen blev en dieselliknande kolvätemolekyl, med en kolatom färre än i utgångsmolekylen. Lika stora dekarboxyleringshastigheter observerades för rena, mättade fettsyror. En jämförelse av deoxygenereringshastigheterna för stearin-, olein- och linolsyra som råvara vid 300oC i närvaro av 1-volymprocent väte på mesoporös Pd/C (Sibunit) avslöjade att katalysatorns aktivitet och selektivitet ökade med en ökande mättningsgrad av reaktantmolekylen. Då stearinsyra användes som utgångsmolekyl, bestod huvudprodukterna av önskade C17-kolväten, medan mängden av aromatiska C17-komponenter ökade, då olein- och linolsyra användes som utgångsmolekyler. Katalysatordeaktiveringen var relativt påfallande vid deoxygeneringen av linolsyra så att endast 3% av fettsyrorna omsattes till produkter i 330 min. Deaktiveringen orsakades av aromatiska C17-komponenter samt av fettsyradimerer, som bildades via en Diels-Alderreaktion. Hydreringen av omättade fettsyror kan därför rekommenderas som ett primärt kemiskt steg i framställningen av miljövänliga dieselprodukter. Målet var också att öka förståelsen av palladiummetallernas roll i nanoskala, speciellt effekten av metallpartiklarna i katalytisk hydrering och deoxygenering. Pd/C-katalysatorer med lika stora halter av Pd syntetiserades och metallens dispersion på bärarmaterialet varierades systematiskt genom en kontrollerad uppväxt av palladiumnanopartiklar på aktiv kolbärare. Metalldispersionens effekt på hydrerings-hastigheten och cis-transförhållandet undersöktes i detalj. En optimal metalldispersion som gav den högsta dekarboxyleringshastigheten hittades. Massöverföringens inverkan på reaktionens hastighet studerades experimentellt och temperaturprogrammerad desorption av kolmonoxid från katalysatorytan undersöktes ingående. Hydrering av växtoljor genomfördes under satsvisa och kontinuerliga betingelser. Både finfördelat Pd/C och katalysatorgranulat användes i experimenten. Ett av målen med arbetet var uppskalningen av hydreringsprocesserna. Med tanke på stora produktionsvolymer var det logiskt att undersöka kontinuerliga hydrerings- och dekarboxyleringsteknologier. En kontinuerlig packad bäddreaktor studerades i laboratorieskala, vilket gav viktig information om katalysatorns långtidsstabilitet och deaktivering. Effekten av rena fettsyror och triglycerider som råvara samt metallpartikelstorleken och palladiumhalten studerades med hjälp av den kontinuerliga reaktorn. Produktionskapaciteten som erhölls med satsvis och kontinuerlig drift jämfördes. Dekarboxyleringen av stearinsyra undersöktes också i en kontinuerlig packad bädd. Omsättningsgraden blev 15% för en stabil katalysator.

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.

Astringent Food Compounds and Their Interactions with Taste Properties

Astringency is traditionally thought to be induced by plant tannins in foods. Because of this current research concerning the mechanism of astringency is focused on tannin‐protein interactions and thus on precipitation, which may be perceived by mechanoreceptors. However, astringency is elicited by a wide range of different phenolic compounds, as well as, some non‐phenolic compounds in various foods. Many ellagitannins or smaller compounds that contribute to astringent properties do not interact with salivary proteins and may be directly perceived through some receptors. Generally, the higher degree of polymerization of proanthocyanidins can be associated with more intense astringency. However, the astringent properties of smaller phenolic compounds may not be directly predicted from the structure of a compound, although glycosylation has a significant role. The astringency of organic acids may be directly linked to the perception of sourness, and this increases along with decreasing pH. Astringency can be divided into different sub‐qualities, including even other qualities than traditional mouth‐drying, puckering or roughing sensations. Astringency is often accompanied by bitter or sour or both taste properties. The different sub‐qualities can be influenced by different astringent compounds. In general, the glycolysation of the phenolic compound results in more velvety and smooth mouthdrying astringency. Flavonol glycosides and other flavonoid compounds and ellagitannins contribute to this velvety mouthdrying astringency. Additionally, they often lack the bitter properties. Proanthocyanidins and phenolic acids elicit more puckering and roughing astringency with some additional bitter properties. Quercetin 3‐O‐rutinoside, along with other quercetin glycosides, is among the key astringent compounds in black tea and red currants. In foods, there are always various other additional attributes that are perceived at the same with astringency. Astringent compounds themselves may have other sensory characteristics, such as bitter or sour properties, or they may enhance or suppress other sensory properties. Components contributing to these other properties, such as sugars, may also have similar effects on astringent sensations. Food components eliciting sweetness or fattiness or some polymeric polysaccharides can be used to mask astringent subqualities. Astringency can generally be referred to as a negative contributor to the liking of various foods. On the other hand, perceptions of astringent properties can vary among individuals. Many genetic factors that influence perceptions of taste properties, such as variations in perceiving a bitter taste or variations in saliva, may also effect the perception of astringency. Individuals who are more sensitive to different sensations may notice the differences between astringent properties more clearly. This may not have effects on the overall perception of astringency. However, in many cases, the liking of astringent foods may need to be learned by repetitive exposure. Astringency is often among the key sensory properties forming the unique overall flavour of certain foods, and therefore it also influences whether or not a food is liked. In many cases, astringency may be an important sub‐property suppressed by other more abundant sensory properties, but it may still have a significant contribution to the overall flavour and thus consumer preferences. The results of the practical work of this thesis show that the astringent phenolic compounds are mostly located in the skin fractions of black currants, crowberries and bilberries (publications I–III). The skin fractions themselves are rather tasteless. However, the astringent phenolic compounds can be efficiently removed from these skin fractions by consecutive ethanol extractions. Berries contain a wide range of different flavonol glycosides, hydroxycinnamic acid derivatives and anthocyanins and some of them strongly contribute to the different astringent and bitterness properties. Sweetness and sourness are located in the juice fractions along with the majority of sugars and fruit acids. The sweet and sour properties of the juice may be used to mask the astringent and bitterness properties of the extracts. Enzymatic treatments increase the astringent properties and fermented flavour of the black currant juice and decrease sweetness and freshness due to the effects on chemical compositions (IV). Sourness and sweetness are positive contributors to the liking of crowberry and bilberry fractions, whereas bitterness is more negative (V). Some astringent properties in berries are clearly negative factors, whereas some may be more positive. The liking of berries is strongly influenced by various consumer background factors, such as motives and health concerns. The liking of berries and berry fractions may also be affected by genetic factors, such as variations in the gene hTAS2R38, which codes bitter taste receptors (V).

Rural Food System Change in Tanzania during the Post-Ujamaa Era. A Case Study from Western Bagamoyo District

Food systems in Sub-Saharan Africa have been rapidly transforming during the recent decades with diverse outcomes on human development and environment. This study explores the food system change in rural villages in eastern Tanzania where subsistence agriculture has traditionally been the main source of livelihood. The focus is on the salient changes in the spatial dimensions and structural composition of the food system in the context of economic liberalization that has taken place after the end of the socialist ujamaa era in the mid-1980s. In addition, the linkages of the changes are examined in relation to food security, socio-economic situation, livelihoods, and local environment. The approach of the study is geographical, but also involves various multi-disciplinary elements, particularly from development studies. The research methods included thematic and questionnaire interviews, participatory tools, and the analysis of land use/ cover data and official documents. Several earlier studies that were made in the area during the late 1970s and 1980s provided an important reference base. The study shows that subsistence farming has lost its dominant role in food provisioning due to the declining productivity of land, livestock losses, and the increasing shift of labour to non-farm sectors. Also rapid population growth has added to the pressure on land and other natural resources. Despite the increasing need for money for buying marketed foods and other necessities, the nutritional situation shows improvement and severe malnutrition has diminished. However, the long-term sustainability of this transformation raises concerns. Firstly, the food security situation continues to be fragile and prone to shocks such as adverse climatic conditions, crop failures and price hikes. Secondly, the commodification of the food system and livelihoods in general is linked to rapid environmental degradation in the area, particularly the loss of soil fertility and deforestation. The situation calls for efforts that take more determined and holistic approaches towards sustainable development of the rural food system with particular focus on the role and viability of small-scale farming.