Bioactive peptides in hydrolysates of bovine and camel milk proteins: A review of studies on peptides that reduce blood pressure, improve glucose homeostasis, and inhibit pathogen adhesion.

The prevalence of diet-related chronic conditions including hypertension and cardiovascular disease, and diabetes mellitus has increased worldwide. Research regarding the use of food-derived bioactive peptides as an alternative strategy to mitigate chronic diseases is on the rise. Milk is recognized as one of the main dietary protein sources for health beneficial bioactive compounds. Hundreds of in vitro studies have suggested that milk-derived bioactive peptides offer multiple biological and physiological benefits, and some but not all were confirmed in vivo with animal models for hypertension, hyperglycemia, and pathogen adhesion. However, only a limited number of health benefits have been confirmed by randomized clinical trials. This review provides an overview of the current clinical studies that target hypertension, postprandial hyperglycemic, and adhesion of enteric pathogen with bioactive peptides derived from bovine and camel milk, with a focus on the factors affecting the efficacy of orally ingested products.

Characterization and biological properties of peptides isolated from dried fermented cow milk products by RP-HPLC: Amino acid composition, antioxidant, antihypertensive, and antidiabetic properties.

This study aimed to assess the biological properties of peptide fractions isolated from dried fermented dairy products (jameed) as influenced by processing. Peptide fractions were separated by reversed-phase high-performance liquid chromatography (RP-HPLC) from salted (Sa) and unsalted (Us) cow milk jameed after drying the fermented curd by sun drying (Sd) or freeze-drying (Fd) and were characterized for their antioxidant capacity and inhibitory activity toward angiotensin I-converting enzyme (ACE) and α-amylase. Sd samples showed more numerous peptide peaks in RP-HPLC chromatograms than Fd samples, regardless of the salt content. High antioxidant activity was evidenced in several peptide fractions from FdUs jameed (including fractions 1, 2, 4, 7, 8, 9, and 10), SdUs jameed (1, 2, 5, 7, and 9), and FdSa jameed (2, 5, 6, and 9). By contrast, peptide fractions from SdSa (1, 2, 3, 5, 8, and 9), SdUs (4, 5, and 10), and FdUs (5, 6, and 8) jameed displayed the highest ACE inhibitory activity. Similarly, the highest inhibition of α-amylase was obtained with fractions from SdSa (1, 2, 3, 4, 5, 6, 8, and 9), SdUs (2 and 6), and FdUs (1, 7 and 9) jameed. A significant negative correlation was evidenced between antioxidant activity and anti-α-amylase activity of peptide fractions from SdSa jameed. These findings demonstrate that cow milk jameed is a source of bioactive peptides with antioxidant, anti-ACE, and anti-α-amylase properties in vitro, which can be tailored by adjusting the salt content and the drying conditions. PRACTICAL APPLICATION: This study shows that cow milk jameed, a staple fermented food in several Mediterranean countries, can serve as a useful source of multifunctional bioactive peptides with potential antioxidant, hypotensive, and hypoglycemic effects, which may help prevent and manage chronic health conditions such as hypertension, type 2 diabetes, and the metabolic syndrome. The bioactivities of certain peptide fractions were enhanced by lowering the salt content of jameed or by the drying method. The relatively simple RP-HPLC method described in this study can be used to isolate the peptide fractions of interest for further characterization and use as functional ingredients.

Evaluation of different drying techniques on the nutritional and biofunctional properties of a traditional fermented sheep milk product.

The purpose of this study was to evaluate the effect of solar and freeze drying techniques on the physicochemical, nutritional and biofunctional properties of salted or unsalted Jameed from fermented sheep milk product. The highest yield of Jameed was obtained via the salted-solar drying process. As measured by colorimetry, salted freeze-dried Jameed showed improved consumer characteristics in terms of increased lightness and decreased red and yellow color components. When unsalted Jameed was prepared by solar or freeze drying, additional major peptide bands were detected by SDS-PAGE treatments as compared to the solar or freeze drying of the salted Jameed. Use of salt in the preparation of solar dried Jameed also led to the highest ACE inhibitory activities whereas antioxidant activity was lowest in unsalted solar dried Jameed. The study findings indicate that both greater yield and better overall nutritional and biofunctional properties were associated with solar dried salted Jameed.

Effects of sun and freeze-drying techniques on molecular, fatty acid and therapeutic properties of fermented goat milk product.

This study investigated the effect of sun drying (Sd) and freeze drying (Fd) on the chemical, nutritional and biological properties of either unsalted (Us) or salted (Sa) Jameed produced from goat milk. The products were characterized by measuring the chemical, physical and biological properties. SDS-PAGE was used to characterize the effect of processing conditions on protein subunits. Major new bands were found in SDS-PAGE of Jameed prepared by SdUs and FdUs from goat milk but not from that prepared by SdSa and FdSa. Preparation of Jameed by with or without salt treatments of Jameed by sun drying enhances the contents of short chain fatty acids. Result showed that the preparation of Jameed by SdUs decreased the content of caprylic acid. That prepared by sun drying and with or without salt increased the stability, shelf life and inhibitory activities of ACE and α-amylase. The optimum color values were found in Jameed prepared by FdSa. Different processing treatments influenced content of all fatty acids except for margaric and oleic acid.