Person: Galarza Iriarte, Uxue
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Galarza Iriarte
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Uxue
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Tecnología de Alimentos
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0000-0002-0521-9242
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811555
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Publication Open Access Evolución de la calidad microbiológica y proteica de productos lácteos concentrados por filtración tangencial(2019) Galarza Iriarte, Uxue; Maté Caballero, Juan Ignacio; Iturmendi Vizcay, Nerea; Escuela Técnica Superior de Ingenieros Agrónomos; Nekazaritza Ingeniarien Goi Mailako Eskola TeknikoaLos concentrados en proteínas lácteas son productos de alto contenido en proteína y bajo en azúcares y grasa. La obtención de los mismos, es objeto de estudio para la utilización en nutrición infantil, deportiva o por sus propiedades funcionales. El objetivo de este trabajo fue estudiar la evolución de la calidad proteica y microbiológica de los concentrados proteicos lácteos respecto a la leche durante el almacenamiento a 4 ºC a 6, 13 y 21 días. El estudio se realizó por triplicado sobre leche obtenida tras microfiltración cerámica (leche MF) y en concentrados líquidos de caseínas (LMCC) y en proteínas séricas (WPC) obtenidas tras una segunda microfiltración con membranas. En el caso de LMCC, fueron productos con diferente concentración (8, 10 y 12 g/100 g producto). La leche MF, LMCC y WPC fueron caracterizados físico-químicamente (pH, extracto seco, proteína total y no caseínica, lactosa) y microbiológicamente (enterobacterias, bacterias mesófilas, lácticas y psicrótrofas). Los resultados principales indican que ambos concentrados proteicos no son estables microbiológicamente más de 6 días a 4ºC al igual que la leche MF, por lo que sería necesaria un tratamiento posterior de pasteurización o equivalente. La degradación de proteínas se observa tras 13 días a 4 ºC tanto en leche MF como en LMCC. La degradación enzimática se produce principalmente en las caseínas β-CN A2 (25-50%), αs1-CN (30%) y β-CN A1 (10-30%); mientras la κ-CN fue la más resistente a la acción de enzimas endógenas y bacterianas. Por otro lado, las proteínas séricas son más resistentes frente a esta hidrólisis, su cantidad se mantiene constante durante 21 días a 4 ºC.Publication Open Access Physical, chemical and microbiological changes in liquid micellar casein concentrates induced by high-pressure treatments(Elseiver, 2022) García Amezqueta, Arantza; Iturmendi Vizcay, Nerea; Galarza Iriarte, Uxue; Maté Caballero, Juan Ignacio; Fernández García, Teresa; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute on Innovation and Sustainable Development in Food Chain - ISFOODMicrofiltration and diafiltration were conducted to obtain 3 distinct levels of liquid micellar casein concentrates from raw skim milk: 8, 10 and 11.5 g casein/100 g. All the concentrates were subjected to 300, 450 and 600 MPa for 5 min. The physicochemical and microbiological changes in the matrix were studied and compared with their untreated counterparts on the day of production and after storing the samples for 7 d at 10 °C. Slight changes in pH were correlated with pressurization; the higher the pressure the greater the decrease in pH. For the least concentrated sample, changes were more noticeable. Furthermore, changes in particle size mainly occurred as a consequence of pressurization but also depended on casein concentration: aggregation and disruption phenomena were observed in the most concentrated samples. In terms of microbial quality, 600 MPa was the only treatment capable of achieving effective microbial control.Publication Open Access Evolution of microbial and protein qualities of fractions of milk protein processed by microfiltration(Elsevier, 2022) Galarza Iriarte, Uxue; Iturmendi Vizcay, Nerea; García Amezqueta, Arantza; Fernández García, Teresa; Maté Caballero, Juan Ignacio; Agronomia, Bioteknologia eta Elikadura; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Agronomía, Biotecnología y Alimentación; Gobierno de Navarra / Nafarroako GobernuaIn dairy industry there has always been great concern about the microbial and protein quality of liquid milk protein fractions obtained by microfiltration (MF). The objectives of research were to study the impact of MF on the evolution of protein and microbial quality of microfiltered milk (MFM), liquid micellar casein concentrates (LMCC) and serum permeates (SP) during storage at 4 °C. This study was carried out with three different batches of milk using diafiltration. Samples were characterized by physicochemical properties; evolution of microbial load and protein (RP-HPLC). Ceramic MF (pore size 1.4 μm) did not change the protein profile, but reduced microbial load by up to 2 log CFU/mL. Polymeric MF (pore size 0.1 μm) was not a sterilizing process since all samples from the permeate presented bacterial growth after 6 days. Protein degradation was observed after 13 days at 4 °C in all studied products. Caseins (CN) were much more affected than whey proteins. β-CN A2 content was reduced by 25–50%, αs1-CN by 30% and β-CN A1 by 10–30%.; κ-CN was the most stable casein. The contents of the whey proteins remained unaltered for 21 days. Protein degradation was likely due to the action of endogenous and bacterial enzymes.Publication Open Access Influence of high hydrostatic pressure treatments on the physicochemical, microbiological and rheological properties of reconstituted micellar casein concentrates(Elsevier, 2020) Iturmendi Vizcay, Nerea; García Amezqueta, Arantza; Galarza Iriarte, Uxue; Barba González-Albo, Carmen; Fernández García, Teresa; Maté Caballero, Juan Ignacio; Agronomia, Bioteknologia eta Elikadura; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Agronomía, Biotecnología y Alimentación