Contribution of Hydrolysis and Drying Conditions to Whey Protein Hydrolysate Characteristics and In Vitro Antioxidative Properties

Whey protein hydrolysates and infant formulas: Effects on physicochemical and biological properties

Whey protein hydrolysates are recognized for their substantial functional and biological properties. Their high digestibility and amino acid composition make them a valuable ingredient to hydrolyzed whey infant formulas, enhancing both product functionality and nutritional values for infant growth. It is important to understand the functional and biological properties of whey protein hydrolysates for their applications in infant formula systems. This review explored preparation methods of whey protein hydrolysates for infant formula-based applications. The effects of whey protein hydrolysate on the physicochemical and biological properties of hydrolyzed whey infant formulas were summarized. The influences of whey protein hydrolysates on the functional and nutritional properties of formulas from manufacturing to infant consumption were discussed. Whey protein hydrolysates are crucial components in the preparation of infant formula, tailored to meet the functional and nutritional demands of the product. The selection of enzyme types and hydrolysis parameters is decisive for obtaining "optimal" whey protein hydrolysates that match the intended characteristics. "Optimal" whey protein hydrolysates offer diverse functionalities, including solubility, emulsification and production stability to hydrolyzed whey infant formulas during manufacturing processes and formulations. They simultaneously promote protein digestibility, infant growth and other potential health benefits, including reduced allergenic potential, as supported by in vitro, in vivo and clinical trials. Overall, the precise selection of enzymes and hydrolysis parameters in the production of whey protein hydrolysates is crucial in achieving the desired characteristics and functional benefits for hydrolyzed whey infant formulas, making them critical in the development of infant nutrition products.

Antioxidant Activity of Sweet Whey Derived from Bovine, Ovine and Caprine Milk Obtained from Various Small-Scale Cheese Plants in Greece before and after In Vitro Simulated Gastrointestinal Digestion

Whey-derived peptides have been associated with different biological properties, but most peptides are usually further hydrolyzed during the digestive process. In the present study, the antioxidant capacity of 48 samples of sweet whey (SW) derived from cheeses obtained from small-scale cheese plants made with bovine, ovine, caprine or a mixture of ovine/caprine milk was assessed using both cell-free and cell-based assays. SW digestates (SW-Ds) and a fraction (<3 kDa; SW-D-P3) thereof were obtained after in vitro digestion and subsequent ultrafiltration. Antioxidant properties using four different assays were evaluated before and after digestion. Our data showed higher values (p < 0.05) for ORAC, ABTS, FRAP and P-FRAP after in vitro digestion (SW-Ds and SW-D-P3) when compared with the corresponding values before digestion. In the non-digested SW, ORAC values were higher (p < 0.05) for the bovine SW compared with all the other samples. In contrast, the ABTS assay indicated a higher antioxidant activity for the ovine SW both before digestion and for SW-D-P3 compared with the bovine SW. The fraction SW-D-P3 of the ovine SW, using HT29 cells and H2O2 as an oxidizing agent, increased (p < 0.05) the cellular antioxidant activity. Furthermore, the same fraction of the ovine/caprine mixed SW increased, through the NF-κB pathway, the expression of SOD1 and CAT, genes implicated in the oxidative response in macrophage-like THP-1 cells. These findings indicate that SW, and particularly bovine and ovine SW, could be a candidate source for physical antioxidants in human and animal nutrition.

Physicochemical characteristics and antioxidant stability of spray-dried soy peptide fractions

The direct addition of health-promoting peptides to food products is limited due to their physicochemical instability and bitter taste as well as their bio-functionality may be influenced by M_W. In this study, SPI hydrolysate (SPIH) was Alcalase-prepared, size-fractionated (<10, 10-30, and 30-100 kD), and the amino acid composition of peptide fractions determined. The physicochemical properties, morphology, and antioxidant stability of the fractions were also investigated after spray-drying encapsulation in maltodextrin-WPC carrier. The two low M_W peptide fractions (especially, PF < 10) were more active than intact SPI, SPIH, and high M_W peptide fraction in scavenging free radicals and chelating transition metal ions. As compared to the particles containing SPIH, those containing the smallest peptide fraction (PF < 10) had higher solubility and hygroscopicity, lower production yield and wettability, and more wrinkles, indentations and surface roughness. The highest antioxidant stability during spray-drying was observed for the two low M_W peptide fractions, which examined by scavenging of free radicals of DPPH (88%), ABTS (97%), OH (93%) and NO (80%), chelating of iron (88%) and copper (87-90%) ions, reducing power (93%), and total antioxidant activity (90%). This finding reflects more structural and biological stability of the low M_W fractions to shear stress and dehydration during spray-drying, as compared with SPIH. The spray-drying encapsulated soy peptide fractions may be used as nutraceuticals for the development of functional foods.

Effects of Spray Drying and Freeze Drying on Physicochemical Properties, Antioxidant and ACE Inhibitory Activities of Bighead Carp (Aristichthys nobilis) Skin Hydrolysates

The physicochemical, structural properties, antioxidant, and angiotensin I-converting enzyme (ACE) inhibitory activities of fish skin protein hydrolysate (SPH) that were freeze-dried (SPH-FD) and spray-dried (SPH-SD) were investigated. SPH-SD showed abundant volatile compounds, higher DPPH radical scavenging activity and ferrous iron chelating activity than SPH-FD, while the ABTS radical scavenging activity and ACE inhibitory activity were not influenced by the drying method. Amino acid compositions showed a higher proportion of proline and hydroxyproline residues in SPH-FD. The major molecular weights were both distributed below 1000 Da. SPH-SD had spherical structures, while SPH-FD had glass shard-like structures. The results indicated that the drying method could affect the physicochemical properties of hydrolysates, and SPH-SD showed potential prospects in developing functional fortified foods.