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We report the evolution of phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylcholine (PC), phosphatidylserine (PS), and sphingomyelin (SM) contents during the production of quark cheese from buttermilk by successive ultrafiltration concentration, enrichment with cream, concurrent homogenization and pasteurization, fermentative coagulation, and separation of quark from whey by further ultrafiltration. Buttermilk is richer than milk itself in phospholipids that afford desirable functional and technological properties, and is widely used in dairy products. To investigate how phospholipid content is affected by end-product production processes such as ultrafiltration, homogenization, pasteurization or coagulation, we measured the phospholipids at several stages of each of 5 industrial-scale quark cheese production runs. In each run, 10,000L of buttermilk was concentrated to half volume by ultrafiltration, enriched with cream, homogenized, pasteurized, inoculated with lactic acid bacteria, incubated to coagulation, and once more concentrated to half volume by ultrafiltration. Phospholipid contents were determined by HPLC with evaporative light scattering detection in the starting buttermilk, concentrated buttermilk, ultrafiltrate, cream-enriched concentrated buttermilk (both before and after concurrent homogenization and pasteurization), coagulate, and quark, and also in the rinsings obtained when the ultrafiltration equipment was washed following initial concentration. The average phospholipid content of buttermilk was approximately 5 times that of milk, and the phospholipid content of buttermilk fat 26 to 29 times that of milk fat. Although phospholipids did not cross ultrafiltration membranes, significant losses occurred during ultrafiltration (due to retention on the membranes) and during the homogenization and pasteurization process. During coagulation, however, phospholipid content rose, presumably as a consequence of the proliferation of the inoculated lactic acid bacteria. In spite of these changes in total phospholipid content, the relative proportions of the phospholipids studied remain fairly stable throughout quark production (PE>PC>SM>PS>PI) and similar to those found in the milk of the region, except that SM content was lower than in milk., (Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Seven batches of Arzúa-Ulloa, a short-ripened soft cow's milk cheese produced in Galicia (NW Spain), were prepared from pasteurized milk. Two control batches of cheese (CB) were made with an acid-aromatic starter containing Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. lactis var. diacetylactis, isolated from raw-milk Arzúa-Ulloa cheeses. Five batches of cheese (LB) were made with the acid-aromatic starter plus one of five strains of mesophilic homofermentative Lactobacillus spp.: four of them isolated from raw-milk Arzúa-Ulloa cheese (characterized in previous works) and the remaining was a commercial Lactobacillus strain. Higher counts of mesophilic viable bacteria, lactic acid bacteria and citrate-fermenting bacteria were found on days 1 or 15 of ripening, while higher counts of lactobacilli were found on day 30 of ripening. On day 1 of ripening the highest diacetyl-acetoin content was noted in the CB, but after day 15 the diacetyl-acetoin content was similar or higher in three of the five LB. The mean degradation of beta-casein in CB was higher than in LB, while the degradation of alpha(s1)-casein was higher in LB. The mean contents of nitrogen-soluble fractions were slightly higher in the LB than in the CB. Volatile free fatty acid (VFFA) contents were, in general, greater in LB than in CB and maximum amounts were determined on day 15 of maturation. Sensorial analysis indicated a more acid taste was in LB, while bitter and astringent tastes were more intense in CB. A positive correlation was found between beta-casein degradation and bitter taste. Yogurt and butter aromas were more intense in CB and in two of the five LB. Firmness was lower in LB and a negative correlation was found between this parameter and alpha(s1)-casein degradation. Crumbliness showed a positive correlation with beta-casein degradation. The use of the Lactobacillus strains assessed in this study is recommended for Arzúa-Ulloa cheese manufacture, in order to enhance the desirable characteristics of this cheese variety, i.e., a soft texture due to alpha(s1)-casein proteolysis but without the bitter taste due to beta-casein degradation and a spicy and slightly rancid aroma and taste.

Ten batches of Cebreiro, a fresh or short-ripened acid-curd cheese, produced in the Galician mountains (NW Spain) were prepared from pasteurized milk inoculated with microorganisms isolated from raw-milk cheese. Two control batches were made with a Lactococcus lactis subsp. lactis starter; 8 batches were made with the lactococcal starter plus one of eight Enterococcus faecalis cultures: 4 E. faecalis var. liquefaciens (EFLB) and 4 E. faecalis var. faecalis (EFFB). Whey dry matter in the EFLB was notably higher than in the control batches and this was related to lower cheese yields. After over 15 days storage the highest counts of both aerobic bacteria and lactic acid bacteria were observed for the EFLB. The lower content in protein on dry matter was found in the EFLB. The beta-casein broke down to a greater extent in the EFLB than in the EFFB, the lowest values being obtained for the control batches. The higher level of hydrolysis of alphax1-casein and maximum peptide alpha(s1) - I/alpha(s1)-casein ratio were obtained for EFFB at day 15 of storage. In all the batches made with enterococci soluble nitrogen was higher than in the control batches, with the highest values in the EFLB. In all the batches made with enterococci, volatile free fatty acid, long-chain free fatty acids and diacetyl and acetoin contents at days 10 and 15 of storage were higher than in the control batches, the highest values being obtained for EFLB. Acetic acid in all batches accounted for the main proportion of the volatile free fatty acids. Butyric and caproic acids were not detected in the volatile free fatty acids fractions of the control batches, but both acids were detected in most of the batches made with enterococci. The more intense acid taste was found in the EFFB and control batches, the most bitter taste being found in the EFLB. Buttery, rancid and spicy flavors were more evident in the EFLB. The rancid and spicy flavors were positively correlated with the contents of volatile free fatty acids and long-chain free fatty acids. The cheeses of EFLB proved to be more crumbly than the EFFB, whereas the stickiness and deformability were higher in the EFFB. The batches with similar organoleptic characteristics to those of traditional cheese were the batch IV made with the less proteolytic strain of E. faecalis var. liquefaciens, and the batch VI made with a moderate lipolytic activity strain of E. faecalis var. faecalis.

Thirty samples of Cebreiro, a fresh or short-time-ripened raw cow's-milk cheese produced in Northwest Spain, were analyzed for the presence of aerobic mesophilic bacteria, (AMC) lactic acid bacteria (LAB), enterococci and Micrococcaceae. Mean AMC and LAB counts exceeding 10(9)/g were higher than those reported for other fresh or short-time-ripened cheeses, although Micrococcaceae occurred in lower numbers (< 10(5)/g) than reported for other raw-milk cheeses. Out of a total of 126 LAB representation isolates, 59 were identified as enterococci (38 as Enterococcus faecalis) 30 as lactococci (24 as Lactococcus lactis subsp. lactis), 25 as leuconostocs (14 as Leuconostoc mesenteroides) and 6 were identified as mesophylic lactobacilli. The enterocci in general were more proteolytic and produced more diacetyl/acetoin than the other LAB groups lactic acid bacteria isolated. It seems that a starter for making Cebreiro cheese should contain these microorganisms so as to reproduce the typical characteristics of traditional raw milk Cebreiro cheeses.

Near-infrared reflectance (NIR) spectroscopy was used to analyze fat, protein, and total solids in cheese without any sample treatment. A set of 92 samples of cow's milk cheese was used for instrument calibration by principal components analysis and modified partial least-square regression. The following statistical values were obtained: standard error of calibration (SEC) = 0.388 and squared correlation coefficient (R2) = 0.99 for fat, SEC = 0.397 and R2 = 0.98 for protein, and SEC = 0.412 and R2 = 0.99 for total solids. To validate the calibration, an independent set of 25 cheese samples of the same type was used. Standard errors of validation were 0.47, 0.50, and 0.61 for fat, protein, and total solids, respectively, and R2 for the regression of measurements by reference methods versus measurements by NIR spectroscopy was 0.98 for the 3 components.

The fungal contamination in 10 farm-level cheesemaking units from Arzúa (A Coruña, Spain) throughout a year was studied. The greatest number of different genera were found in the air and, although in lesser amounts, in the cheese. The isolation frequency for the most representative genera in cheese were Rhizopus (26,8%), Cladosporium sp. (22,5%), Geotrichum sp. (17,7%), Penicillium sp. (17,1%) and Aspergillus sp. (8,1%). © 2002 Altaga. All rights reserved. Resumen Se ha estudiado el tipo de contaminantes fúngicos en 10 queserías artesanales de la zona de Arzúa (A Coruña, España) durante un año. Como medio de cultivo se utilizó agar extrato de malta suplementado o no con Rosa de Bengala. El mayor número de géneros diferentes se encontró en el aire y, aunque en menor medida, en los quesos. Las frecuencias de aislamiento de los géneros más representativos en los quesos fueron: Rhizopus (26,8%), Cladosporium sp. (22,5%), Geotrichum sp. (17,7%), Penicillium sp. (17,1%), Aspergillus sp. (8,13%). © 2002 Altaga. Todos los derechos reservados. Palabras clave: Hongos, Contaminación, Queso. Resumo Estudiouse o tipo de contaminantes fúnxicos en 10 queixerías artesanais da zona de Arzúa (A Coruña, España) durante un año. Como medio de cultivo utilizouse agar extrato de malta suplementado ou non con Rosa de Bengala. O maior número de xéneros diferentes encontrouse no aire e, anque en menor medida, nos queixos. As frecuencias de illamento dos xéneros máis representativos nos queixos foron: Rhizopus (26,8%), Cladosporium sp. (22,5%), Geotrichum sp. (17,7%), Penicillium sp. (17,1%) e Aspergillus sp. (8,13%). © 2002 Altaga. Tódolos dereitos reservados. Palabras chave: Fungos, Contaminación, Queixo. [ABSTRACT FROM PUBLISHER]