Physicochemical and functional properties of goat milk whey protein and casein obtained during different lactation stages

Goat's Milk Powder Enriched with Red (Lycium barbarum L.) and Black (Lycium ruthenicum Murray) Goji Berry Extracts: Chemical Characterization, Antioxidant Properties, and Prebiotic Activity

The current trend in food innovations includes developing products containing plant ingredients or extracts rich in bioactive compounds. This study aimed to prepare and characterize skimmed thermally treated goat's milk powders enriched with lyophilized fruit extracts of Lycium ruthenicum Murray (GMLR) and Lycium barbarum L. (GMLB). Proximate analysis, ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), Fourier transform infrared spectroscopy using attenuated total reflection (FTIR-ATR), and electrophoretic analysis were assessed. Total phenolic content (TPC), total protein content, and antioxidant properties of enriched goat milk powders were determined spectrophotometrically, and prebiotic potential was evaluated by the broth microdilution method. A total of 25 phenolic compounds and 18 phenylamides were detected in the enriched goat milk powders. Electrophoretic analysis showed the absence of proteolysis in the prepared powders. The GMLR showed the highest TPC and displayed a ferric ion-reducing power, probably contributed by anthocyanins and some phenylamides. GMLR and GMLB had higher ABTS radical scavenging activity but lower ferrous ion-chelating capacity than control goat's milk powder. GMLB and GMLR in a dose-dependent manner (0.3-5 mg/mL) showed a growth-promoting effect on probiotic strains. In summary, prepared goji/goat milk powders, primarily GMLR, might be used as prebiotic supplements or functional food additives.

Therapeutic effect of goat milk and its value-addition: current status and way forward

Goats are important livestock mainly recognized for their low rearing costs and adaptability to harsh climate making them suitable for small farmers. Goat's milk has been tagged as highly consumed milk in many parts of the world and also carry essential substances as minerals, vitamins, enzymes, proteins, electrolytes and fatty acids which are easily metabolised by the body. The unique health benefits of goat milk make it a remedy for various disease conditions. Additionally, the low allergenicity and high digestibility of goat milk make it a popular dairy product for infants and immunocompromised individuals. This review summarizes the efforts and achievements made in analyzing goat milk's nutritional, therapeutic, and functional properties and its current applications in the food and nutraceuticals sector. Also, the article provides insights into the diverse range of food and cosmetics applications of goat milk-derived components. Besides the long history of the use of goat milk for human nutrition, the scientific literature concerning various bioactive components and their beneficial therapeutic effects with respect to modern science are also reviewed in detail.

Age-specific composition of milk microbiota in Tibetan sheep and goats

This study investigates the dynamic changes in milk nutritional composition and microbial communities in Tibetan sheep and goats during the first 56 days of lactation. Milk samples were systematically collected at five time points (D0, D7, D14, D28, D56) post-delivery. In Tibetan sheep, milk fat, protein, and casein contents were highest on D0, gradually decreased, and stabilized after D14, while lactose and galactose levels showed the opposite trend. Goat milk exhibited similar initial peaks, with significant changes particularly between D0, D7, D14, and D56. 16S rRNA gene sequencing revealed increasing microbial diversity in both species over the lactation period. Principal coordinates analysis identified distinct microbial clusters corresponding to early (D0-D7), transitional (D14-D28), and mature (D56) stages. Core phyla, including Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, dominated the milk microbiota, with significant temporal shifts. Core microbes like Lactobacillus, Leuconostoc, and Streptococcus were common in both species, with species-specific taxa observed (e.g., Pediococcus in sheep, Shewanella in goats). Furthermore, we observed a highly shared core microbiota in sheep and goat milk, including Lactobacillus, Leuconostoc, and Streptococcus. Spearman correlation analysis highlighted significant relationships between specific microbial genera and milk nutrients. For instance, Lactobacillus positively correlated with total solids, non-fat milk solids, protein, and casein, while Mannheimia negatively correlated with protein content. This study underscores the complex interplay between milk composition and microbial dynamics in Tibetan sheep and goats, informing strategies for livestock management and nutritional enhancement. KEY POINTS: • The milk can be classified into three types based on the microbiota composition • The changes of milk microbiota are closely related to the variations in nutrition • Filter out microbiota with species specificity and age specificity in the milk.

Exploring the health benefits and functional properties of goat milk proteins

Goat milk proteins are unique in their nutritional and functional properties and have become increasingly popular in recent years. A variety of methods have been studied for extracting and isolating these proteins, with coprecipitation being a particularly effective approach. Compared to cow milk proteins, goat milk proteins contain higher levels of certain amino acids such as tryptophan and cysteine, while maintaining similar nutritional properties. Additionally, they have superior functional properties, including better emulsifying and foaming properties, which make them an attractive option for developing new food products. Research has shown that goat milk proteins have several health benefits, including immunomodulatory effects, allergy management, anti-inflammatory, and antioxidant effects, as well as antimicrobial and anticancer properties. They have the potential to be used as a treatment for autoimmune diseases, allergies, and other immune system disorders due to their ability to modulate the production of cytokines and other immune system components. Furthermore, their antimicrobial properties can help prevent the growth of harmful bacteria and reduce the risk of infection. Future research will focus on the potential of goat milk proteins as a functional food ingredient, their effects on gut health and microbiota, and their therapeutic potential for various health conditions. This research may lead to the development of new functional foods that promote health and prevent disease, and potentially pave the way for the use of goat milk proteins as a therapeutic agent for various health conditions.

Developmental changes in proteins of casein micelles in goat milk using data-independent acquisition-based proteomics methods during the lactation cycle

Casein micelles (CM) play an important role in milk secretion, stability, and processing. The composition and content of milk proteins are affected by physiological factors, which have been widely investigated. However, the variation in CM proteins in goat milk throughout the lactation cycle has yet to be fully clarified. In the current study, milk samples were collected at d 1, 3, 30, 90, 150, and 240 of lactation from 15 dairy goats. The size of CM was determined using laser light scattering, and CM proteins were separated, digested, and identified using data-independent acquisition (DIA) and data-dependent acquisition (DDA)-based proteomics approaches. According to clustering and principal component analysis, protein profiles identified using DIA were similar to those identified using the DDA approach. Significant differences in the abundance of 115 proteins during the lactation cycle were identified using the DIA approach. Developmental changes in the CM proteome corresponding to lactation stages were revealed: levels of lecithin cholesterol acyltransferase, folate receptor α, and prominin 2 increased from 1 to 240 d, whereas levels of growth/differentiation factor 8, peptidoglycan-recognition protein, and 45 kDa calcium-binding protein decreased in the same period. In addition, lipoprotein lipase, glycoprotein IIIb, and α-lactalbumin levels increased from 1 to 90 d and then decreased to 240 d, which is consistent with the change in CM size. Protein-protein interaction analysis showed that fibronectin, albumin, and apolipoprotein E interacted more with other proteins at the central node. These findings indicate that changes in the CM proteome during lactation could be related to requirements of newborn development, as well as mammary gland development, and may thus contribute to elucidating the physical and chemical properties of CM.

Multi-Objective Optimization of Beverage Based on Lactic Fermentation of Goat’s Milk Whey and Fruit Juice Mixes by Kefir Granules

Numerous fruits are produced in Ecuador, of which about 40% are never eaten. In addition, fresh goat cheeses are in high demand. However, goat cheese generates goat milk whey with high contamination loads, and, therefore, it must be adequately treated before being discharged into ecosystems. This research aims to use a mixture of tree tomato, common strawberry juices, and goat’s milk whey, to be statically fermented by milk and water kefir grains (WKG) for 48 h. For this, a dual mixture design of L-optimal response surface methodology was carried out to find the conditions that maximized all the responses evaluated (lactic-acid bacteria and yeasts concentrations and the overall acceptability assessed on a 7-point scale). Experiments were carried out in San Gabriel, Ecuador. Temperatures during the day and night were 20.2 ± 0.3 °C and 18.7 ± 0.3 °C, respectively. Three conditions were selected, where the highest response values were reached. Complementary experiments demonstrated the validity of the models. When comparing the results of the present study with similar ones carried out previously, higher values were observed in the concentration of yeasts, which seems related to the presence of the WKG. It is concluded that they could be suitable functional beverage candidates.