Browsing by Subject "galaktoglukomannaani"
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(2017)Elintarvike-emulsioiden lipidifaasin hapettuminen voi merkittävästi heikentää elintarvikkeen laatua. Stabilointiaineella on vaikutusta emulsion kemialliseen ja fysikaaliseen pysyvyyteen. Kuusesta eristetty hemiselluloosa, galaktoglukomannaanin (GGM), stabiloi hyvin öljy vedessä -emulsioita sekä fysikaalisesti että kemiallisesti. Tutkielman kirjallisuusosiossa tarkasteltiin hemiselluloosien eristysmenetelmien vaikutusta hemiselluloosan rakenteeseen ja fenolisten yhdisteiden pitoisuuteen sekä hemiselluloosien mahdollisia käyttösovelluksia elintarvikkeissa. Lisäksi tarkasteltiin fenolisten yhdisteiden vaikutusta o/w-emulsioiden kemialliseen pysyvyyteen. Työn kokeellisessa osassa selvitettiin eri menetelmillä kuusesta eristettyjen hemiselluloosien sisältämien fenolisten yhdisteiden vaikutusta emulsion lipidifaasin hapettumiseen ja emulsion fysikaaliseen pysyvyyteen. Emulsioiden stabilointiin käytetyt hemiselluloosat olivat kuusen termomekaanisesta massasta eristetyt GGM:t, jotka oli kuivattu joko sumutuskuivauksen (tTMP-GGM) tai etanolisaostuksen (eTMP-GGM) avulla, kuusen sahajauhosta paineistetulla kuumavesiuutolla eristetty GGM (PHWE-GGM) ja alipaineessa kuumalla vedellä eristetty BLN-GGM. Lisäksi tutkittiin, lisäsikö kuusen fenoliuute GGM:lla stabiloidun emulsion pysyvyyttä. Emulsioiden valmistuksessa käytettiin antioksidanteista puhdistettua rypsiöljyä ja emulsioita säilytettiin 40 C:ssa valolta suojattuna. Emulsioiden lipidifaasin hapettumista seurattiin kahden viikon ajan määrittämällä peroksidiluku spektrofotometrisesti, heksanaalipitoisuus head space -kaasukromatografisesti ja jatkoreaktiotuotteiden pitoisuus kokoekskluusiokromatografisesti. Emulsioiden rakennetta ja pisarakokojakaumaa tarkasteltiin optisella mikroskoopilla ja partikkelikokoanalysaattorilla. Fenolisten yhdisteiden pitoisuuksien muutokset kahden viikon aikana määritettiin emulsion jatkuvasta faasista ja rajapinnoilta erikseen erittäin suuren erotuskyvyn nestekromotografisella menetelmällä. Emulsioiden hapettumiskestävyys pysyvimmästä epäpysyvimpään oli seuraava: tTMP > PHWE > eTMPF > eTMP. tTMP-emulsion lipidifaasi ei hapettunut lainkaan. Kaikissa emulsioissa havaittiin fenolisten yhdisteiden pitoisuuden pienenemistä jatkuvassa faasissa tai rajapinnalla. Useammin fenolisten yhdisteiden pitoisuus pieneni rajapinnalla. Fenoliuutteen lisääminen vähensi eTMP-emulsion hapettumista. Kaikilla hemiselluloosilla stabiloidut emulsiot BLN-GGM:a lukuun ottamatta olivat fysikaalisesti pysyviä kahden viikon ajan. PHWE-emulsion keskimääräinen pisarakoko oli pienin. Emulsioiden kemialliseen ja fysikaaliseen pysyvyyteen arvioitiin vaikuttavan sekä pisarakokojakauma että fenolisten yhdisteiden antioksidatiivisuus. Tulevaisuudessa olisi mielenkiintoista selvittää, miksi pienimolekyylinen PHWE-GGM muodostaa pienempiä lipidipisaroita kuin suurimolekyyliset tTMP- ja eTMP-GGM:t.
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(2018)The addition of new oat-based ingredients: beta-glucan, protein and oil was investigated in a beverage product to increase the protein and unsaturated fat content of vegetable drink produced from oatmeal or oat flour. Due the low natural water-solubility of proteins and large molar mass of beta-glucan, these biopolymers do not emulsify oil-in-water emulsion sufficiently and there is a need to add a primary emulsifier. Spruce galactoglucomannan (GGM) has both emulsification and stabilization capacity. The stabilizing effect of GGM has been previously studied on a model of oil-in-water emulsion system. In the present study, the stabilizing properties of GGM was studied in a beverage model where oat protein and beta-glucan were added in an oat oil emulsion system. Heat treatment is an essential part of manufacturing commercial beverages and therefore the effect of pasteurization on GGM-stabilized emulsion was also studied. The literary survey explores the ingredients used in commercial beverages and studies of beverage manufacturing. The literary survey also presents the properties of GGM and other ingredients used in experimental part and the factors affecting emulsion stability. The product model was prepared in a two-stage process in which the GGM emulsified oat oil-in-water emulsion (O) and protein (P) and beta-glucan suspensions (B) were prepared separately and mixed together into beverage product models, OP and OPB. The droplet size was measured from the oat oil emulsion (O). Morphology was examined with an optical microscope from both the emulsions and the product models. The effect of the time on the stability of the product models was determined by measuring the separation of phases. The factors affecting stability were determined also with rheological viscosity measurements and turbidity measurements. The oat oil emulsions’ (O) morphology was homogenous and the average droplet size was small. In product models OP and OPB the homogeneity of emulsions was lost and large undissolved particles or particle clusters were visualized. The oil droplets were seen between the particles and around the particle clusters as small droplets packed in to the spaces between and on the surface of the particle clusters. The viscosity was the highest in the composition OPB and the effect of the time on the viscosity was the most notable. The pasteurization increased the viscosity in the composition OPB compared with the unpasteurized samples. The pasteurization generally increased the stability. There was no oil layer at the top of the beverage models OP and OPB which indicates that the morphology of the oil droplets did not break down during the evaluated shelf-life. The color of produced beverage emulsion resembled that of café au lait. Water separated during storage was easily mixed back with the beverage product model after shaking.
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(2011)Emulsified films are prepared by drying an emulsion. Polysaccharide based emulsified films consist of film-forming polysaccharide, fat, emulsifier and plasticiser. In the literature review, the materials used in the preparation of polysaccharide based emulsified films were discussed. The review also included a discussion of which factors affect the water barrier and mechanical properties of the emulsified films. The aim of the experimental study was to find out the potential of konjac glucomannan (KGM) and galactoglucomannan (GGM) in emulsified films. The effect of fat type and fat content on the water barrier and mechanical properties of the films were studied. Emulsified films which contained 30% (wt-% of GGM) fat were prepared from beeswax, rapeseed oil and pine wood oil. Fat contents of 10 and 50% were also used for beeswax. Emulsified films were compared with control films that did not contain any fat. The ratio of KGM and GGM used was 1:1. The water vapour permeability (WVP), water vapour transmission rate (WVTR), Young’s modulus, tensile strength and elongation at break were measured. Films were also viewed with a scanning electron microscope (SEM). KGM and GGM were suitable materials for emulsified films. The surfaces of films dried at room temperature were more uniform than those dried at 60 °C. In the SEM images, wax droplets were smaller than oil droplets. The diameter of oil droplets was about 10 ?m and 2–6 ?m for wax droplets. Wax droplets were better entrapped in the film matrix probably due to their smaller size. As expected, best water barrier properties were obtained with films containing 50% beeswax (p < 0.05). WVP of the films decreased when the content of beeswax in the film increased. Films containing 30% oils and 10% beeswax did not differ significantly from the control film in water barrier and in mechanical properties. The lowest Young’s modulus was with 50% beeswax film. The control film was the stiffest and strongest. There were no statistically significant differences in elongation at break between the films. Emulsified films were successfully prepared from KGM and GGM. The water barrier properties of emulsified films were better than those of the control film and still the mechanical properties were rather well maintained.
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(2014)Aerogels are lightweight, porous and dry foams that are produced from gels by replacing the liquid phase by air. When produced from polysaccharide-based hydrogels, potential applications for aerogels could be found as bio-based packaging materials. The literature review focused on the production of polysaccharide-based hydrogels and their chemical crosslinking, as well as the production of aerogels and their properties. In the experimental study the possibilities for utilization of spruce galactoglucomannan (GGM), an abundant but largely unexploited raw material, as aerogel matrix was explored. Nanofibrillated cellulose (NFC) was used as reinforcement and the polysaccharides were crosslinked with ammonium zirconium carbonate (AZC). Hydrogels were prepared from GGM-NFC-suspensions and heat treatment was performed in order to induce crosslinking reaction. Prepared hydrogels were frozen in a bath of carbon dioxide ice and ethanol and subsequently freeze-dried into cubic aerogels. The aim was to investigate the effect of polysaccharide proportions and AZC content on the strength of hydrogels and on the mechanical properties and moisture sensitivity of aerogels. The formation of crosslinks was observed indirectly from the values of storage and loss moduli by dynamic rheological measurement. The strength of hydrogels was highly dependent on the AZC and NFC content. In contrast, the compressive modulus of aerogels instead was affected only by NFC content at relative humidity (RH) of 50% and 23 °C. Hydrogel strength could not be used for prediction of aerogel strength under these ambient conditions. AZC and NFC mainly decreased the sensitivity of aerogels towards moisture by decreasing the water absorption and its plasticizing effect on aerogels. The effect of crosslinking on mechanical and physical properties of aerogels appeared clearly at RH over 50%. GGM was shown to be a suitable aero-gel raw material when combined with NFC. The role of NFC in enhancing the aerogel’s me-chanical properties was significant. The mechanical properties of uncrosslinked aerogels, how-ever, weakened in a humid environment. In particular, AZC is needed to protect aerogels from the plastizicing effect of water. Properties of crosslinked aerogels in a humid environment would be an interesting subject of further studies.
Now showing items 1-4 of 4