No abstract

Camel milk produces watery texture when it is processed to yogurt. Despite the extensive studies on microbial transglutaminase (MTGase) in dairy research, the effect of this enzyme on the properties of yogurt made from camel milk has not been studied. This study aims to investigate the impact of MTGase with and without bovine skimmed milk powder (SMP), whey protein concentrate (WPC),or b-lactoglobulin (b-lg) on physico-chemical, rheological, microstructural, and sensory properties of camel-milk yogurt during 15 days of storage period. MTGase treatment markedly reduced the fermentation time of unfortified and SMP-fortified camel milk. The fortification of camel milk without MTGase failed to give settype yogurt. The treatment of unfortified milk with MTGase enormously improved the viscosity and the body of yogurt samples. Fortification of MTGase-treated milk impacted positively on the viscosity, the water holding capacity, and the density of the protein matrix in the gel microstructure, which were influenced by the type of dairy ingredients. All MTGase-treated yogurts differed from each other in hardness and adhesiveness values. Electrophoresis results showed that the susceptibility of the individual milk proteins to MTGase varied, and there were differences among the treatments toward the enzyme. SMP-fortified yogurt was the most accepted product. Generally, the addition of MTGase preparation at a concentration of 0.4%, simultaneously with starter culture, to fortified camel milk was considered an effective tool to solve the challenges of producing set-type yogurt from this milk.

This study investigated the impact of supplementing goats' milk with quinoa extracts, in the range of 5, 10 and 15 g/100 g on the milk fermentation. The properties of yoghurt produced from this milk, which include viscosity, microstructure and sensory acceptability, were assessed. The supplementation of goats' milk with quinoa extracts, particularly permeate extract, reduced the fermentation time and enhanced the viability of lactic acid bacteria. Supplementation of yoghurt with increased levels of quinoa extracts increased the apparent viscosity and changed the yoghurt protein matrix. Panellists highly accepted the yoghurt that contained quinoa permeate extract.

In this study, milk was hydrolyzed using protease (Asperigillus oryzae), trypsin, pepsin, or papain at concentrations of 0.001, 0.005, or 0.01 g/100 g milk for 30 or 60 min to produce angiotensin-converting enzyme inhibitory and antioxidant peptides. Results showed that the proteolysis, antioxidant, and ACE-I activity gradually increased with the increase in the enzyme concentration and hydrolysis time. The protease-treated milk had the highest proteolytic and ACE-I activity, while the papain-treated milk had the lowest. The papain-treated milk exhibited the greatest Fe 2+ chelating activity. The use of trypsin at concentration of 0.001 g/100 g milk for 60 min produced ACE-I and antioxidant activity without changes in the technological properties of milk.

Although goat milk and their processing products were recommended for human consumption as a medicinal food, their strong goaty flavor limits their acceptability among the majority of consumers especially in Egypt. In this respect, Βeta-Cyclodextrin (β-CD) was reported to be effective in reducing the intensity of this flavor and as a result the commercial value of goat milk products was enhanced. In this research, the effect of reducing goat milk flavor in soft goat cheese by β-CD and their effect on texture and microstructure were investigated. The obtained results showed that the addition of β-CD at different concentrations (0.25g, 0.5 or 1.0% of milk) effectively trapped the short chain fatty acids and made goaty flavor un-sensed. The increase in moisture% and decreased in total solids% as a result of β-CD addition was also noticed. The addition of β-CD (0.25%) to goat milk cheese lead to an increase in firmness, cohesiveness, gumminess and chewiness and a decrease in springiness and resilience when compared to control. Electron micrographs of different goat cheese samples showed obvious microstructural changes in the protein network as affected by β-CD and these changes were Compatible with the changes in moisture and firmness.

In this study, skim milk was fermented using 14 strains for 16 h at 42 °C or for 48 h at 25 °C. On conclusion of fermentation, the proteolytic, angiotensin converting enzyme-inhibitory (ACE-I), and antioxidant activities as well as the inhibition of thrombin and cholesterol micellar solubility were determined. The results revealed that B-4564 exhibited the highest ACE-I activity (68.11%) under the 42 °C for 16 h condition, while B-1445 demonstrated the highest ACE-I activity (92.23%) under the 25 °C for 48 h condition. B-4564 exhibited the highest inhibition rate of thrombin (42.43 and 48.10%) and cholesterol (68.60 and 87.01%) under the 42 °C for 16 h and 25 °C for 48 h conditions, receptively. B-442 exhibited the highest DPPH radical scavenging activity of 95.63 and 62.89% under the 42 °C for 16 h and 25 °C for 48 h conditions, receptively. B-1445 demonstrated the highest Fe chelating activity and reducing power under both the tested fermentation conditions.

In this study, skim milk fermented with 14 commercial dairy starters were evaluated for their proteolysis ability, angiotensin I-converting enzyme (ACE)-I, and antioxidant properties. The antioxidant activity was determined using DPPH radical scavenging, chelating of Fe ions, and reducing power assays. The results showed that the coagulation time, pH, and titratable acidity varied among the used starters and appeared to be starter dependent. Lh-B02 starter had the highest proteolytic and ACE-I activity.-01, Yo-Fast 1, YC-281, MYE 96, and YO-MIX 205 starters had the highest DPPH radical scavenging activity. Chelating of Fe ions of the -01 starter was the highest, whereas the O-114 starter was the greatest in reducing power. Regarding the yogurt starters, Yo-Fast 1 starter exhibited h igh values o f proteolytic, ACE-I, and DPPH radical scavenging activity. A positive correlation was observed between the proteolytic and ACE-I or antioxidant activities of all starters.

Antioxidative, antidiabetic, and hypolipidemic properties of probiotic-enriched fermented camel milk (FCM) combined with Salvia officinalis L. leaves hydroalcoholic extract (SOHE) in streptozotocin-induced diabetes in rats were investigated. Phytochemicals analysis and antioxidant capacity indicated that S. officinalis contained high phenolics with super antioxidant activity. Subsequently, HPLC analysis demonstrated 13 phenolic acids and 14 flavonoids in considerable amounts with ferulic acid and resveratrol as predominant, respectively. The antidiabetic and hypolipidemic properties of FCM and SOHE were examined in a designed animal model consisting of seven treated groups for four weeks. There was a negative group (G1); the positive group (G2) received a single dose (50 mg kg−1) of streptozotocin (STZ) by intraperitoneal injection (i.p.); in G3, diabetic rats (DRs) orally received 5 mL FCM kg−1 daily; in G4, DRs orally received 50 mg GAE SOHE kg−1 daily; in G5, DRs orally received 5 mL FCM contains 25 mg GAE SOHE kg−1 daily; in G6, DRs orally received 5 mL FCM contains 50 mg GAE SOHE kg−1 daily; in G7, DRs orally received 50 mg metformin kg−1 daily. Combining FCM with SOHE at 25 or 50 mg kg−1 exhibited a synergistic effect in significantly lowering random blood glucose (RBG), fasting blood glucose (FBG), and improved weight gain recovery %. The hypolipidemic effect of FCM + 50 mg GAE SOHE kg−1 was significantly higher than using FCM or SOHE individually, and attenuation in triglycerides (TG), total cholesterol (CHO), and high- and low-density lipoproteins (HDL and LDL), and very-low-density lipoproteins (VLDL) was remarked. Combining FCM with SOHE at 25 or 50 mg kg−1 ameliorated liver and kidney functions better than individual uses of FCM, SOHE, or metformin. Interestingly, FCM with 50 mg SOHE kg−1 presented significant improvement in the activity of antioxidant enzymes, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and a substantial reduction in malonaldehyde (MDA) levels with 53.75%, 89.93%, 63.06%, and 58.69% when compared to the STZ group (G2), respectively. Histopathologically, administrating FCM + 25, 50 mg SOHE kg−1 or 50 mg kg−1 metformin showed a normal histological structure of both islets of Langerhans cells and acini. In conclusion, combining FCM with SOHE presented synergistic and therapeutical efficacy. It could be beneficial and profitable for controlling diabetes mellitus complications and protecting against oxidative stress.