Browsing by Author "Partanen, Riitta"
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Item Butter oil process development for ideal cream(2018-12-11) Penttinen, Henna; Partanen, Riitta; Hokkanen, Sanna; Kemian tekniikan korkeakoulu; Bankar, SandipItem Changes in milk fat globules and membrane lipids under the shear fields of microfiltration and centrifugation(Elsevier Science B.V., 2019-03-01) Jukkola, Annamari; Hokkanen, Sanna; Kämäräinen, Tero; Partanen, Riitta; Heino, Antti; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Valio Ltd.This study compared the efficiency of centrifugal and microfiltration separation of milk fat globules (MFG) from bovine cream and the changes that take place in the corresponding lipid membranes (MFGM). Creams were washed with water (1:10) and subjected to either centrifugation or microfiltration to fractionate proteins and other non-fat milk components. Protein analyses of the obtained fractions were carried out by gel electrophoresis. Lipid extraction and thin layer chromatography were also employed to separate lipid types and the amount of polar lipids were determined by gas chromatography. The effect of flow conditions on MFG's colloidal properties and MFGM components was evaluated based on estimates of the average rate of energy dissipation in microfiltration and centrifugation processes. Both were equally effective in removing the protein fraction (93% yield) as well as non-fat dry matter (~100% removal). Microfiltration reduced the mean particle size by 0.3 µm, whereas the opposite was observed for centrifugal separation (average size increase by 0.8 µm). The latter process also induced a more significant reduction in the electrostatic charges (zeta potential) of the colloids in the cream, which relates to the changes in the milk fat globule surface composition and the release of MFGM components. The dissociated polar lipids amounted to 24% and 20% upon centrifugation and microfiltration, respectively. Overall, the results suggest that MFG and MFGM are partially damaged under the shear forces typical of centrifugal and microfiltration separation. A high separation efficiency, with minimal fat globule damage and high MFGM yield is possible by adopting microfiltration under carefully optimized conditions.Item Effects of conventional processing methods on whey proteins in production of native whey powder(Elsevier BV, 2021-05) Muuronen, Klaus; Partanen, Riitta; Heidebrecht, Hans-Jürgen; Kulozik, Ulrich; School services, CHEM; Department of Bioproducts and Biosystems; Valio Ltd.; Technische Universität MünchenNative whey, produced by microfiltration of skim milk, has great potential in infant nutrition and as a functional food ingredient; however, processes to produce whey powder using high temperatures can adversely affect protein quality. The individual effects of three critical processing steps were investigated: standard thermal pasteurisation, membrane concentration and spray drying on protein quality when performed under the mildest conditions considered feasible for industrial operation. HPLC-analysis was used to measure the degree of denaturation of the six most abundant whey proteins (β-lactoglobulin, α-lactalbumin, bovine serum albumin, immunoglobulins, lactoferrin and lactoperoxidase) before and after each processing step. Overall, denaturation was minimal throughout our tests, although the tendency to denature was unequal between the individual proteins and also varied between tested processing types and medium compositions. In the production of native whey with microfiltration, retentions varied greatly between the proteins but were not affected by pasteurisation of milk.Item Food emulsifiers based on milk fat globule membranes and their interactions with calcium and casein phosphoproteins(ELSEVIER SCI LTD, 2019-09) Jukkola, Annamari; Partanen, Riitta; Xiang, Wenchao; Heino, Antti; Rojas, Orlando J.; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Valio Ltd.Natural food surfactants were produced from membrane-derived fragments of milk fat globules (MFGM) obtained from cream and buttermilk by microfiltration with diafiltration followed by churning. The obtained MFGM fragments were demonstrated for their emulsifying and functional properties and as substitute of commercial phospholipids (lecithin). Fine emulsions (droplet size ∼1.2 μm) were obtained by stabilization of the oil/water interface after low energy sonication. Stable emulsions were obtained with lecithin in the pH range between 5.8 and 7.8, whereas MFGM components enabled better stability above pH 6. Coalescence took place in the presence of calcium, owing to electrostatic screening. The stability of the emulsions increased with the addition of casein, which formed droplet flocs. The calcium-binding ability of MFGM is proposed to inhibit protein (casein) flocculation, leading to a highly interacting network that prevents phase separation and stable MFGM-based food emulsions.Item Mobility and oxidative stability in plasticised food matrices the role of water(VTT, 2008) Partanen, Riitta; Kemian ja materiaalitieteiden tiedekuntaThe importance of water in food structure and stability is well known, and the role of water as a plasticiser for biopolymers has been extensively studied during the last 25 years. Recently, understanding of the mechanisms of water plasticisation of glassy carbohydrate matrices at the molecular level has increased and its relevance to the rate of mass transfer has been emphasized. There appears to be a lack of such studies with food proteins, although the water factor is similarly recognised for example in protein-based edible films. Furthermore, food stability is currently evaluated on the basis of water activity and the physical state of the matrix. Therefore, it would be important to consider whether the major food polymers, starch-based carbohydrates and proteins, really act similarly with respect to water. In the present work, the role of water in system stability and biopolymer interactions was studied in two different systems: cast films with and without plasticiser and spray-dried particles with a dispersed lipid phase. Plasticisation of amylose films by glycerol and water was studied by proton NMR relaxometry. In glassy amylose the proximity of Tg did not strongly affect the amylose mobility. The second moment M2, which is a measure of strong dipolar interactions and decreases with increasing distance between the protons contributing to it, decreased slightly with increasing water content. It was thus suggested that glassy state swelling occurred in amylose film. Swelling behaviour is probably important when mass transfer in the matrix is considered. In rubbery state, high concentration (30%) of glycerol increased the mobility of amylose despite the phase separation that occurs in these systems already at much lower plasticiser content. The data on mobility of plasticised amylose was combined with results presented earlier on oxygen permeability of these films. Although increasing mobility generally resulted in increased permeability, conditions were found in which the plasticiser induced segmental motions in amorphous amylose without appreciable loss in oxygen barrier properties. In powder particles, the stability of embedded lipid phase was studied in traditional carbohydrate carriers, i.e. hydrolysed (maltodextrin with gum Arabic as an emulsifier) and modified (octenyl succinate derivative) starches, and in whey protein isolate. Powders with oils rich in volatile flavour or in polyunsaturated fatty acids were prepared by spray-drying and characterised by laser diffraction and scanning electron microscopy for oil distribution and by differential scanning calorimetry for their glass transition temperatures (Tg). The powders were stored under controlled conditions, and the effect of relative humidity on the rate of oxidation was studied by following the increase in peroxide value during storage. Formation of hydroperoxides is linked with oxygen transfer in the system, as it is the oxygen consuming step of the reaction. In the case of powders with embedded oil rich in volatiles, the release of limonene and carvone was studied as a function of time and temperature. The starting hypothesis of this work was that a higher water vapour sorption at higher humidity would increase oxygen permeation in the matrices and lead to an increased rate of oxidation. This was in fact found to be the case in carbohydrate matrices during storage at 20°C, at which temperature the rate of oxidation in matrices was higher at RH 54% than at RH 11%. An opposite behaviour was found for bulk oil, suggesting that the effect of water in matrix-dispersed oil was due to matrix properties. At elevated temperatures, a difference was found between hydrolysed and modified starches. The stability of oil in modified starch still correlated with the proximity of Tg, whereas the hydrolysed starch completely lost its barrier properties at 50°C, which could not be explained by the Tg of the matrix. When volatiles release was studied at elevated temperature (70°C), little release from dry matrices was found. Intense release was found in the proximity of the glass transition temperature in all the systems. In whey protein isolate matrix, oxidation of matrix-embedded oil was retarded compared to that of bulk oil at all humidities, but followed almost the same pattern as bulk oil with respect to humidity. The rate of oxidation was high at low humidities (RH 0% and RH 11%), was retarded at intermediate humidities (RH 50% and RH 75%) and again increased at high humidity (RH 90%), at which caking of the powder was observed as an indication of physical instability. Thus, it appeared that water did not have a similar role in the matrix formed of globular proteins as it had in a glassy carbohydrate matrix. The importance of storage conditions and matrix properties for relating oxygen transfer to the rate of oxidation was demonstrated. Furthermore, it was proposed that the high solubility of the volatiles in non-volatile triglyceride phase was the reason for the retention of limonene and carvone in the matrices at elevated temperatures.Item Oxygen transport across interfaces in oil-water emulsions(2013) Lähteenmäki, Maija; Forssell, Pirkko; Partanen, Riitta; Biotekniikan ja kemian tekniikan laitos; Kemian tekniikan korkeakoulu; School of Chemical Engineering; Laakso, SimoItem Partitioning of the milk fat globule membrane between buttermilk and butter serum is determined by the thermal behaviour of the fat globules(Elsevier BV, 2021-01) Hokkanen, Sanna P.; Partanen, Riitta; Jukkola, Annamari; Frey, Alexander D.; Rojas Gaona, Orlando; Department of Bioproducts and Biosystems; Bio-based Colloids and Materials; Molecular biotechnology; Valio Ltd.Isolation of the industrially interesting milk fat globule membrane (MFGM) components from dairy streams is challenging, and a full exploitation of their benefits can be gained by better understanding of the behaviour of the fat globule membrane fraction during milk fat processing. In this study, microfiltration of the cream before churning and the comprehensive compositional analysis of the process streams revealed new insights on MFGM partitioning during the phase inversion in butter making. After removal of the smallest fat globules by microfiltration, a reduced phospholipid content was reflected in the buttermilk, but not in the butter serum. Regardless of the cream washing, buttermilk and butter serum lipids were different in PL-to-fat ratio, phospholipid composition, degree of unsaturation and melting behaviour. We suggest that partitioning of the MFGM fraction between butter and buttermilk is a direct result of the physico-chemical properties of the fat globules, partly related to the globule size.
