Lien entre le niveau de lipolyse du lait de chèvre et la qualité sensorielle des fromages au lait cru ou pasteurisé

Abstract

-Link between goat milk lipolysis and sensorial quality of lactic goat cheeses made from raw or pasteurised milk. There is an important variability of the lipolysis level in goat milk, due to various physiological and breeding factors. The aim of this study was to evaluate the impact of these natural variations on the sensorial quality of fresh and ripened lactic goat cheeses. The effect of milk pasteurisation was also studied. The results show that the variation of the lipolysis level of goat milk do not have any significant effect on the sensorial quality of ripened cheeses. On the contrary, the sensorial quality of fresh cheeses is linked to the lipolysis level of milk. These results allowed us to recommend some means of controlling the sensorial quality of goat cheeses. For ripened cheeses, a satisfying sensorial quality could be obtained via the control of the technological parameters, notably the moisture in non-fat cheese at the demoulding. For fresh cheeses, the lipolysis level of milk should be checked before cheesemaking, and milks with high lipolysis levels should not be used. Pasteurisation of milk induced a decrease in the lipolysis level of cheeses. The use of pasteurisation led to a limitation of the appearance of organoleptic defects in ripened cheeses, but the overall flavour and odour of ripened cheeses made from pasteurised milk was also reduced compared to cheeses made from raw milk.goat milk / lipolysis / goat cheese / sensorial quality / pasteurisation Résumé -Il existe une importante variabilité du niveau de lipolyse du lait de chèvre en raison de divers facteurs liés à la physiologie de l'animal et aux conditions de production. L'objectif de cette étude était d'évaluer l'impact de ces variations naturelles sur la qualité sensorielle de fromages de chèvre lactiques (type bûchette) frais et affinés. L'incidence de la pasteurisation a également été étudiée. Les résultats montrent que le niveau de lipolyse du lait n'a pas d'effet significatif sur la qualité sensorielle des fromages affinés. En revanche, la qualité sensorielle des fromages frais est directement liée au niveau de lipolyse des laits. Ces résultats permettent d'envisager des actions de maîtrise de la qualité sensorielle des fromages de chèvre. Pour les fromages affinés, l'obtention d'une qualité sensorielle satisfaisante nécessite une maîtrise des paramètres technologiques et notamment le contrôle de l'humidité du fromage dégraissé au démoulage. Pour les fromages frais, un contrôle du niveau de lipolyse des laits mis en fabrication doit être réalisé et l'utilisation de laits présentant des niveaux élevés de lipolyse doit être évitée. L'utilisation de laits pasteurisés permet de réduire le niveau de lipolyse des fromages et la fréquence d'apparition des défauts organoleptiques pour les fromages affinés. Toutefois, la pasteurisation des laits conduit aussi à des fromages affinés ayant une flaveur globale et une odeur globale moins prononcées.lait de chèvre / lipolyse / fromage de chèvre / qualité sensorielle / pasteurisation

Influence of autochthonous adjunct cultures on ripening parameters of Argentinean goat's milk cheeses

“…In particular, cheese‐making trials with E. faecium and their controls differed in degree of lipolysis in comparison with other cheese‐making trials. Some authors have pointed that differences in the initial level of lipolysis of fresh milk, changes in composition at the fat/protein interface and accessibility of the fat substrate to lipolytic enzymes can be among the sources of this variation.…”

“…The information reported in relation to the effect of inclusion of adjunct cultures on cheese lipolysis is variable, depending on strains used, cheese‐making technology and duration of ripening process, among other factors. In fact, inter‐species and strain differences in esterase activity have been detected in 15 species of LAB isolated from Cheddar cheese . Kondyli et al .…”

Effect of mid-line or low-line milking systems on lipolysis and milk composition in dairy goats

“…stronger, more acid or spicier) in the cheeses made with milk from ML milking. In any case, these values are far from those reported by other authors as causing off-flavours in goat's cheeses (3.5 meq/100 g milkfat, Morgan et al ., 2001). However, it seems prudent not to directly extrapolate these results to the environment of the current work, given the differences in milk composition and the cheese manufacturing process.…”

“…Further studies along these lines would be warranted to determine whether the use of ML or HL milking can negatively affect the quality of goat's milk; a crucial aspect when considering that goat's milk is mainly used to manufacture cheese, whose sensory characteristics might be affected by an increase in the FFA concentration as a result of excessive lipolysis in the milk. In this sense, Morgan et al (2001) noted a high risk of obtaining lactic coagulation cheeses with unacceptable sensory characteristics when the FFA concentration is ⩾1 g oleic acid/100 g milkfat (3.5 meq/100 g milkfat) in goat's milk. However, there is no information on the effect of lipolysis on the sensory quality of cheeses made by enzymatic coagulation, a processing technique widely used in traditional goat cheese-making of Mediterranean countries.…”

“…In this sense, Morgan et al . (2001) noted a high risk of obtaining lactic coagulation cheeses with unacceptable sensory characteristics when the FFA concentration is ⩾1 g oleic acid/100 g milkfat (3.5 meq/100 g milkfat) in goat's milk. However, there is no information on the effect of lipolysis on the sensory quality of cheeses made by enzymatic coagulation, a processing technique widely used in traditional goat cheese-making of Mediterranean countries.…”