Comparaison de la composition physicochimique du lait camelin et bovin du Sud tunisien; variation du pH et de l’acidité à différentes températures

Abstract

RésuméLa composition physicochimique du lait de chamelle est variable selon l'alimentation des animaux, les conditions environnementales ainsi que la période de lactation. Dans le but de déterminer la composition du lait de chamelle du sud tunisien, le lait camelin de la région a été comparé à celui bovin sur le plan de l'acidité et du pH du lait des deux espèces en fonction de la température du milieu. Le lait de chamelle est plus acide (17,25 ± 1,035°D) et moins dense (d= 1,027± 0,003) que le lait de vache. Le lait de vache est plus riche en matière protéique (34,15 ± 3,11 g/L), matière sèche (119,43 ± 15,34g/L) et azote non protéique NPN (1,04 ± 0,08g/L). Le suivi de la variation du pH et de l'acidité du lait camelin et bovin à trois températures différentes (température ambiante (25°C), à 4°C et à -4°C) a révélé une acidification plus lente du lait de chamelle dans les trois cas avec une conservation durant 30 heures à température ambiante, 7 jours dans le réfrigérateur (4°C) alors quelle est de 5 jours pour le lait de vache à la même température. La congélation du lait à -4°C peut ainsi constituer une méthode simple pour la conservation du lait camelin qui n'est accessible que dans les régions de sa production. Mots-clés :Lait, chamelle, vache, composition physicochimique, acidité, température Afrique SCIENCE 05(2) (2009) 293 -304Amel SBOUI et al. 294 Abstract Comparison of the gross composition of Tunisian camel and cow milk; Variations of pH and acidity at various temperaturesThe gross composition camel milk is variable according to the food of the animals, the environmental conditions as well as the period of lactation. This study is aiming to determine the composition of camel milk from south of Tunisia in comparison with cow milk and to follow the variations of theirs pH and acidity at various temperature. The physical analysis of milk showed that camel milk is more acid and less dense than the cow milk. Its viscosity (3.21 ± 0.41) is significantly higher than that of bovine milk (2.46 ± 0.53). The chemical composition showed that bovine milk is richer in protein (34.15 ± 3.114 g/L), dry matter (119.43 ± 15.34g/L) and Non Protein N (NPN) (1.04 ± 0.08g/L). The follow-up of pH and acidity variations of milk from the two at three different temperatures (ambient temperature (25°C, + 4°C and -4°C) revealed a slower acidification of camel milk ( 7 days at (4°C)). On the other hand frozen camel or cow milk can be conserved several weeks and thus constitute a simple method for storing up milk especially camel milk which is accessible only in arid lands.

Fatty acid profile comparison and hygienic quality of cow and camel (Camelus dromedarius) milk in Algeria

“…This acidity was closer to the one reported by Siboukeur (2007): 18.2 ± 2.93°D. Nevertheless, many authors, gave higher or equal to 15°D values such as Sboui et al (2009) and Kamoun (1995) in Tunisia with respectively 17.2°D and 15.6 ± 1.4°D and Abu-Lehia (1994) in Saudi Arabia (15 ± 4°D).…”

“…CamelcowThe result regarding acidity is confirmed by several authors who studied camel milk: 6.41 (Sboui et al, 2009); 6.31 ± 0.15 (Siboukeur, 2007) and 6.49 (Abu-tarbouch et al, 1998;Sawaya et al, 1984). Other works about camel milk provided higher pH values: 6.61 ± 0.02 in Egypt (Mehaia et al, 1995); 6.55 ± 0.04 in Saudi Arabia (Abu-Lehia, 1994) and 6.51 ± 0.12 in Tunisia (Kamoun, 1995).…”

Biochemical, Physico-Chemical and Microbiological Properties of Camel Raw Milk Marketed in Bechar city (South-West Algeria): Hygienic and Safe Consumers Approach

“…However, many authors report values less than 4.5 g/l, such as Alloui-lombarkia et al., (2007) in Algeria (1.512), Kamoun (1995) in Tunisia (1.56g/l), Sboui et al, (2009) (1.72g/l), Siboukeur (2007) (1.82g/l) and Chethouna (2011) (1.8g/l). The results obtained are comparable to the density values reported by FAO (1995) with 1.026 and appear to be slightly higher compared to data of Siboukeur (2007) (1.0230) and Chethouna (2011) (1.0220).…”

Monitoring Shelf Life of Pasteurized Whole Milk Under Refrigerated Storage Conditions: Predictive Models for Quality Loss

“…On average, the pH of fresh milk was 6.75, in the acceptable range for commercial milk. The normal pH for bovine milk ranges from 6.6 to 6.8, with an average of 6.7 (Klaenhammer ; Jensen ; Walstra and others ; Sboui and others ).…”