The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Most of the classification methods so far published for cheese varieties which are based either on rheological or compositional properties appear to be inadequate. Still, a promising approach in this area of cheese research is the application to proteolytic patterns of multivariate statistics such as principal component analysis (PCA) and discriminant analysis (DA). Both techniques were therefore...
Using the same microfiltered milk, three raw milk Swiss-type minicheeses were made after addition of three different retentates; one, remaining bacteria-free, was used as reference. The experiment was repeated three times at two different seasons. Factorial discriminant analyses were made on biochemical, physico-chemical and microbiological data at 12 weeks (end of warm storage, 18 °C) and 24...
The main requirements for reliable sensory descriptive data are presented in this text. The importance of panellist selection is emphasised and some guidelines and examples are given. The steps identified for obtaining a sensory profile are detailed. Some vocabulary lists developed for cheese evaluation are presented. Advice is given on the conditions required for the collection of sensory descriptive...
Proteolysis is the principal and most complex biochemical event which occurs during the maturation of most cheese varieties. Proteolysis has been the subject of much study and a range of analytical techniques has been developed to assess its extent and nature. Methods for assessing proteolysis can be classified under two broad headings: non-specific and specific techniques, both of which are reviewed...
An efficient method for the simultaneous determination of free amino acids (FAA) and biogenic amines (BA) was applied to the analysis of presumed raw milk cheeses of the following types: Emmental (n = 18), Bergkase (n = 28), semi-hard cheeses (n = 18) and soft cheeses (n = 41). The absolute amounts of FAA and BA largely varied, but the relative amounts could be classified into four groups independently...
The growth conditions of S thermophilus and L delbrueckii subsp lactis in Swiss-type cheese have not been fully studied. Since these bacteria show a low proteinase activity, it was assumed that their growth in cheese could depend on the preliminary hydrolysis of caseins by coagulating enzymes and plasmin. The purpose of this work was to develop a simple method which would allow us to measure the...
The free amino acid development of Appenzeller, Emmentaler, Gruyere, Raclette, Sbrinz and Tilsiter cheese is described. During the first five months of cheese ripening, the total amount of the free amino acids increases by 140-290 mg kg -1 per day. Gruyere shows the highest increase for 15 amino acids, Appenzeller for valine, methionine, phenylalanine and ornithine, Raclette for α-...
The peptidases and esterases of thermophilic lactobacilli and dairy propionibacteria, which are known to participate in the ripening of Swiss-type cheeses, are mainly intracellular. Their release in cheeses requires a necessary autolytic event. The aim of this review is to summarize the current knowledge on autolysis of cheese-related thermophilic lactobacilli and dairy propionibacteria, focussing...
The present article reviews the most commonly used methods, techniques and equipments for instrumental analysis of volatile (flavour) compounds in milk and dairy products. After listing some previous important review articles, several methods commonly used for sample treatment are described, as well as the following techniques for extraction and concentration prior to gas chromatographic (GC) analysis:...
In cheese, flavour and taste are, in great part, generated by the starters during the ripening stage. Proteolysis and lipolysis are the first steps of the elaboration of a large number of taste and odour compounds directly involved in the sensory quality of cheeses. The pathways used by the microorganisms to produce flavour compounds are still unclear in many cases. It would be useful for the starter-producing...
An intracellular aminopeptidase from Brevibacterium linens ATCC 9174 was purified 4300-fold to homogeneity using ammonium sulphate fractionation, anion exchange chromatography, hydrophobic interaction chromatography and anion exchange chromatography. The pH and temperature optima were 8.5 and 35 °C, respectively. The purified aminopeptidase was stable over the range pH 8 to 10, and was thermally...
Trends in the fracture strain, modulus of deformability and chemical properties as a function of storage time were determined for Cheddar cheese made in the New Zealand Dairy Research Institute's pilot plant. The apparent fracture strain of Cheddar cheese increased during the first 14-28 days and thereafter decreased. α s1 -Casein levels decreased monotonically and non-protein nitrogen...
Different reconstituted skimmed milk powders, as well as defatted pasteurized and raw milk, were used to probe the effects of preheating conditions on rennetability and molecular availability of casein to coagulate and to form a curd. The experiments for following coagulation and gel formation were carried out using the tormagraph at pH 6.4, 35 °C, and 3.8% total protein. Two new approaches to estimate...
Eight strains of Lactococcus starter bacteria were tested under microbiologically controlled conditions for their ability to produce Cheddar cheese flavour. For this purpose, aseptic Cheddar cheese curds were prepared with each of the organisms, and the resulting curds slurried with sterile salt and water, and stored at 30 °C for accelerated flavour development. Distinct though weak Cheddar cheese...
Milk samples from 340 Merino and 234 Lacha sheep were analyzed by isoelectric focusing in thin gels with carrier ampholytes. Five different β-lactoglobulin (β-Lg) phenotypes (A, B, AB, AC and BC) were observed in milk from the Merino breed, but only three phenotypes were found in milk from the Lacha breed (A, B and AB). Differences in gene frequencies between flocks were observed. The gene frequencies...
In an attempt to obtain 15 N-labelling milk proteins for digestive studies in humans, labelled ammonium sulphate [( 15 NH 4 ) 2 SO 4 ] was incorporated in the diet of dairy cattle. Cows were fed a total mixed ration including 300 g (NH 4 ) 2 SO 4 . In trial 1, three cows received a single dose of 50, 150 or 300 g ( 1 ...
Milk containing ∼ 1.7% fat, but protein in the range ∼ 2.6-3.4% was prepared by mixing calculated quantities of whole milk, skim milk and an ultrafiltration (UF) permeate obtained from skim milk or quarg acid whey. The freezing point (FP) of each milk was measured before and after ultra-high temperature (UHT) heating. The concentration of lactuloselysine, determined indirectly as furosine value (FV),...
Casein fractions from milk and various cheeses as well as isolated casein standards were analysed by capillary electrophoresis under acidic conditions. Capillary electrophoresis was performed on a Waters Quanta 4000 apparatus with a hydrophilically coated or an untreated fused-silica capillary. The four major caseins in an acid precipitate from milk were well separated. In addition, the various...
A proteinaceous antimicrobial compound from Pseudomonas fluorescens ATCC 948 was purified to homogeneity by chromatography steps and characterized. The compound showed a large spectrum of activity. Inhibition of thermophilic Lactobacillus, Listeria monocytogenes, Enterobacteriaceae and P fluorescens strains was mainly detected. The antimicrobial compound produced in skim milk had an apparent molecular...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.