Comparative study on emulsifying and physico-chemical properties of bovine and camel acid and sweet wheys

Effects of Spray Drying, Freeze Drying and Gamma Irradiation on the Antioxidant Activities of Camel and Cow Milk Fractions

This work aimed to establish an integrated approach to investigate the total phenolic content and antioxidant activities of dried skim camel and cow milk and their fractions. The milk fractions were obtained by acid or enzymatic coagulation followed by spray drying (inlet temperature/outlet temperature: 125 ± 2 °C/90 ± 2 °C) or freeze drying (−50 °C, 0.05 mbar) coupled or not to gamma irradiation (at 5, 11, 22 kGy). The results showed that the total phenolic content (measured in gallic acid equivalent, GAE) varied depending on the drying technique. The freeze-drying process corresponded to the highest values of total phenolic compounds, with 247.23 ± 2.08 mg GAE/100 g powder for the β-casein fraction of camel milk (βC CaM) and 621.13 ± 4.16 mg GAE/100 g powder for the β-casein fraction of cow milk (βC CoM). Compared to spray-dried fractions, freeze-dried fractions showed generally higher ferric reducing antioxidant power for both camel milk and cow milk. The highest values of free radical scavenging activity were seen in the spray-dried β-casein fractions of camel milk (βC CaM) and cow milk (βC CoM) and in the freeze-dried acid whey of cow and camel milk (AW CaM and AW CaM). Freeze-dried acid whey (AW CaM and AW CoM) appeared to be less sensitive to gamma irradiation at 5 and 11 kGy.

Impact of alkaline electro-activation treatment on physicochemical and functional properties of sweet whey

The impact of alkaline electro-activation (EA) on the protein solubility, foaming, and emulsifying characteristics of whey was investigated. EA caused protein aggregation and conjugation. At low electric current and holding time, proteins aggregation through disulfide bonds was observed, whereas increasing currents and holding times caused proteins to conjugate with sugars such as lactose, lactulose and galactose. The EA process improved the protein solubility at the pH range of 4.0-7.0. Compared to untreated whey, which produced micron-sized and unstable emulsions at pH 3, whey samples treated under 750 mA and 24-48 h holding time formed nano-sized and stable emulsions at this pH. Furthermore, although both untreated and EA-whey produced stable emulsions at pH 7, those emulsions prepared with EA-whey had smaller particle size and were more stable against droplet flocculation. EA-treated whey tended to generate foams with significantly higher overrun and stability. The present study demonstrated that EA can enhance the functionality of whey.

Comparison of Ethanol Stability and Chemical Composition of Camel Milk from Five Samples

This research was carried out to study the variation in ethanol stability and chemical composition of five camel milk samples, including two pasteurized samples (Alwatania and Darir alabaker) and three raw samples (Majaheim, Wadah, and Hamra). Ethanol stability was analyzed by dispersing camel milk samples with 0 to 100% ethanol (v/v). The findings indicate that camel milk samples precipitated after adding an equal volume of ethanol at concentrations between 50% and 64% ethanol, depending on the milk sample. The addition of sodium chloride at different concentrations (1−10%) to camel milk resulted in a significant increase in ethanol stability, and samples from Majaheim and Alwatania exhibited the highest ethanol stability values (88%). In contrast, the addition of EDTA to camel milk for pH ranging between 5.9 and 7.1 has increased ethanol stability with a sigmoidal shape in camel milk. The largest ethanol stability differences were observed in a camel milk sample from Alwatania. Thus, the level of Ca2+ in camel milk may contribute to ethanol stability by shifting the entire profile to higher ethanol stability values. The chemical composition of different camel samples was also determined. The lactose content of camel milk varied significantly (p < 0.05) across samples, ranging from 4.37% in Majaheim camel milk to 4.87% in Alwatania camel milk. The total solids of camel milk varied significantly between raw and pasteurized samples, ranging between 10.17% and 12.10%. Furthermore, protein concentration in camel milk obtained from different camel samples varied, from 2.43% to 3.23% for Hamra and Alwatania, respectively. In conclusion, ethanol stability in camel milk was dependent on the camel breed, pH level, ionic strength, and EDTA addition.

Conjoint application of ultrasonication and redox pair mediated free radical method enhances the functional and bioactive properties of camel whey-quercetin conjugates

Ultrasonication, redox-pair generated free radical method and their combination (Ultrasonication/redox-pair method) was used for production of camel whey-quercetin conjugates. FTIR and SDS-PAGE confirmed successful production of whey-quercetin conjugates using ultrasonication and ultrasonication/redox-pair method. FTIR suggested existence of covalent (appearance of new peak at 3399 cm-1) and non-covalent linkages (shifting of peak at 3271 cm-1, 1655 cm-1 (amide I), 1534 cm-1 and 1422 cm-1 (Amide II)) in the whey-quercetin conjugates. Moreover, SDS-PAGE of conjugates produced by ultrasonication as well redox-pair method indicated shifting of protein bands slightly towards high molecular weight due to increase in the mass of proteins due to the binding of polyphenols. All conjugates showed improved techno-functional and bioactive properties in comparison to whey proteins. Conjugates produced through ultrasonication showed smaller particle size, improved solubility, emulsifying and foaming properties while conjugates produced through ultrasonication/redox-pair method depicted superior antioxidant properties in comparison to whey. Furthermore, conjugated samples showed higher inhibition of enzymatic markers involved in diabetes and obesity with highest potential recorded in conjugates produced using ultrasonication. Therefore, ultrasonication can be successfully used individually as well as in combination with redox-pair for production of whey-quercetin conjugates with enhanced bioactive and techno-functional properties.