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-The aim of this study was to investigate the angiotensin I-converting-enzyme (ACE)-inhibitory activity of tryptic hydrolysates of ovine β-lactoglobulin, and of yoghurts made by using different starters. Ovine β-lactoglobulin (a mixture of variants A and B at a ratio of 50/50) was subjected to trypsin activity. The degree of hydrolysis of native whole β-lactoglobulin reached 56, 72, 93 and 95% after 1, 2, 8 and 24 h, respectively. ACE-inhibitory activity of tryptic hydrolysates increased with the time of hydrolysis, yielding 85, 88 and 92% after 2, 12 and 24 h, respectively. The determination of ACE-inhibitory activity of some tryptic peptides separated by RP-HPLC and identified by mass spectroscopy showed that the more hydrophilic peptides showed the higher activity. Yoghurts obtained by fermentation of ovine milk with four different sets of starters, and their fractions soluble or not at pH 4.6 also showed an ACE-inhibitory activity. The maximum activity was obtained in the case of insoluble fractions at pH 4.6 of yoghurts made with the set of starters YC-183. ovine milk / tryptic peptide / yoghurt / ACE-inhibitory activity Résumé -Activité inhibitrice de l'enzyme de conversion de l'angiotensine I (ECA) de peptides trypsiques de la β-lactoglobuline du lait de brebis et de yoghourts obtenus à partir de diffé-rents levains. Une activité inhibitrice de l'enzyme de conversion de l'angiotensine I (ECA) a été recherchée dans les peptides trypsiques de la β-lactoglobuline du lait de brebis et dans des fractions issues de yoghourts fabriqués à partir de différents ferments lactiques. La β-lactoglobuline ovine (un mélange des variants A et B) a été soumise à une hydrolyse trypsique. Les degrés d'hydrolyse de la β-lactoglobuline ont atteint 56, 72, 93 et 95 % respectivement après 1, 2, 8 et 24 h d'hydrolyse. L'activité inhibitrice de l'ECA des hydrolysats trypsiques augmentait avec la durée de l'hydrolyse, atteignant 85, 88 et 92 % respectivement après 2, 12 et 24 h. La détermination de l'activité inhibitrice de l'ECA de quelques peptides trypsiques séparés par CLHP en phase inversée et identifiés par spectrométrie de masse a montré que les peptides les plus hydrophiles présentaient l'activité la plus

Yoghurts are mostly produced from cow milk and to a very limited extent from ewe milk. The evolution of caseins and whey proteins in ovine milk submitted to different thermal treatments (63 degrees C/30 min; 73 degrees C/15 min; 85 degrees C/10 min or 96 degrees C/5 min) was followed during fermentation of yoghurts and during their storage up to 14 days, using two different sets of starters. One set of starter LAB was a "ropy" culture (YC-191), which is a well-defined mixed strain culture containing Streptococcus thermophilus ST-143 and Lactobacillus delbrueckii subsp. bulgaricus (LB-18 and LB-CH2). The other set of starter bacteria (YC-460) was a standard yoghurt culture("non-ropy") containing mixed strain culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Contents of free amino groups in produced yoghurts increased gradually during the fermentation, up to a maximal value obtained after 4 h fermentation, then they did not change significantly during storage of yoghurt produced with YC-191 starter. In contrary, a large drop in the amount of free amino groups was observed in the first 24 h of storage in the case of yoghurt made with YC-460 indicating that microorganisms continue still to grow in low temperatures. During fermentation and storage of both yoghurt types, alpha-lactalbumin was hydrolyzed to a slightly bigger extent than beta-lactoglobulin. During fermentation, beta-casein was slightly more degraded than alpha(s)-caseins; however, the opposite was observed during storage up to 14 days. Generally, a more intense heat pretreatment led to a higher degradation of whey proteins and caseins during fermentation and storage. Differences in proteolytic activity between the two starters used (whey proteins more degraded by YC-191; caseins more degraded by YC-460) may lead to improvement in production and formulation of yoghurts differing in their physicochemical and rheological properties.

The present study aimed to investigate synergistic health effects of camel milk and Bif. longum BB536 in rats with diet-induced obesity, impaired lipid profile, and hypercholesterolemia. Wistar rats received a high-fat (HF) diet plus 2 ml/day of either cow’s milk fermented with yogurt culture (CT), camel milk fermented with yogurt culture (CAT), camel milk fermented with Bif. longum BB536 (CAP), mixed cow’s and camel milk fermented with yogurt culture (CCAT), or cow’s milk and camel milk fermented with Bif. longum (CCAP). All fermented milk products significantly reduced HDL, albumin, and total protein. The percentage change in body weight gain was between −40% (CAP) and −24% (CT) and in serum triglycerides between −54% (CCAP) and −37% (CT); for the other parameters, changes caused by CCAP/CT were −40%/−22% (total cholesterol), +29%/+8% (HDL), −73%/−54% (LDL), −54%/−37% (VLDL), −52%/−14% (AST), −53%/−31% (ALT), +43%/+25% (albumin), +37%/+25% (total protein), −48%/−27% (urea), and −34%/−16% (creatinine). Camel or cow’s milk fermented with yogurt culture or Bif. longum significantly improved negative effects of the HF diet on body weight, blood lipid profile, serum proteins, liver and kidney markers, and severity of the metabolic syndrome. Milk and fermentation culture acted synergistically with camel milk and Bif. longum generally showed stronger positive effects./