Influence of raw milk microflora on the characteristics of Swiss-type cheeses : II. Biochemical and sensory characteristics

Abstract

Summary -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 weeks (end of cold storage, 7 "C), At each ripening period, 'raw milk' cheeses were easily and significantly separated from the reference cheese. At 12 weeks, the three 'raw milk' cheeses were separated on the basis of propionic fermentation products, and to a lesser extent on proteolysis and levels of facultatively heterofermentative lactobacilli and starter lactic acid bacteria. At 24 weeks, differentiation was mainly based on proteolysis, since volatile fatty acids and lactate concentrations were nearly the same, irrespective of the cheeses. The same conclusions were drawn for win ter and autumn chee ses. Based on sensory evaluations made at the end of ripening, it was also possible to differentiate between the different 'raw milk' cheeses in winter and in autumn. Reference cheeses were always clearly separated from the other cheeses. The qualitative and quantitative importance of the indigenous microf1ora of milk on the biochemical and sensory characteristics of Swiss-type cheeses has been discussed.Swiss-type minicheese 1 microflora 1 proteolysis 1 volatile fatty acid 1 sensory analysis Résumé -Influence de la microflore du lait cru sur les caractéristiques des fromages à pâte pressée cuite: II. Caractéristiques biochimiques et sensorielles. Des minifromages à pâte pressée cuite ont été fabriqués à partir de lait cru microfi!tré, auquel étaient ajoutés des rétentats provenant de trois origines différentes. Chacun des trois rétentats issus de la microfiltration était réincorporé dans le lait microfiltré de mélange, pour obtenir trois fromages dits au «lait cru». Le lait microfiltré serOral communication at the IDF Symposium 'Ripening and Quality of Cheeses', Besançon, France, February 26-28, 1996. 152 y Demarigny el al vait de témoin. L'expérimentation a été répétée trois fois, en automne et en hiver. Une analyse factorielle discriminante a été effectuée, pour chaque saison, sur les données biochimiques, physico-chimiques et microbiologiques collectées à 12 semaines (sortie cave chaude, 18 "C) et à 24 semaines (sortie cave froide, 7 "C). À chaque stade, les fromages au «lait cru» se différenciaient significativement du témoin. De plus, à 12 semaines, il était déjà possible de caractériser les trois fromages au «lait cru», principalement à partir de leur profil fermentaire, et dans une moindre mesure sur les niveaux de protéolyse et de certaines populations microbiennes (lactobacilles hétérofermentaires facultatifs, bactéries lactiques du levain). À 24 semaines, la différenciation portait essentiellement sur les niveaux de certains paramètres de protéolyse, les concentrations en lactate, acétate et propion...

Relationships between ruminant management and sensory characteristics of cheeses: a review

“…A part of the differences in micro-organisms diversity in milk from different farms or plants [37,39,44,84] could be due to animal feeding. It has been recently suggested that terpenes, whose plant-specific origin has been documented, may have an indirect impact on cheese sensory properties by modifying the dynamics of the microbial ecosystem during cheese-making and ripening.…”

Characterisation of the non-starter lactic acid bacteria (NSLAB) of Gruyère PDO cheese

“…Comparison of cheeses made from raw milk with those made from microfiltered or pasteurised milk has shown that the raw milk flora plays an essential role in the development of the sensory characteristics of hard cheeses. In most cases it was found that elimination of the raw milk flora leads to a less intense cheese flavour [6,10,17]. Several studies further indicated that mesophilic adjuncts can exert a positive effect on flavour [5,8,19].…”

Relationships between flavour and chemical composition of Abondance cheese derived from different types of pastures

“…The above-mentioned authors observed differences in volatile compound composition in cheeses -whether these compounds were of microbial origin or originated from the feed -that may be linked to differences in flavour. On the one hand, there may be a specific type of microflora in each production zone, as has been demonstrated [18,21], which would lead to significant variations in the sensory quality of the cheese [7,12,20]. On the other hand, certain compounds present in forage, such as terpenes, may be found later in the dairy products [40] and thereby contribute to cheese aroma [8,9,22,24,39].…”