This work intended to compare dromedary yogurt’s characteristics obtained by a co-fermentation process with plant (carob powder) or autochthonous bacteria (
Enterococcus faecium
and
Streptococcus ...macedonicus
). For this reason, the ultrafiltration process (UF) is applied to increase the rate of total solids in dromedary milk within the margin needed to prepare a yogurt. Carob powder or autochthonous bacteria were incorporated at the level of 2% in UF milk. Then mixtures were fermented with the strains
Lactobacillus bulgaricus
and
Streptococcus thermophiles
, and the obtained products are named CFC (yogurt with carob), CFS (yogurt with autochthonous strains) and control (yogurt with only
L. bulgaricus
and
S. thermophilus)
respectively. All along of 3 weeks at cold, CFC and CFS maintained
Streptococcus
at appropriate levels (>8 log CFU/g). Moreover, CFC showed the lowest syneresis, highest cohesiveness and springiness values, and oleic acid (C18:1n9; 26.315%). However, CFS yogurt resulted in higher volatile compound formation than CFC and control, where isobornyl propionate was the major one.
Milk protein hydrolysates have received particular attention due to their health-promoting effects. Dromedary milk differs from the milk of other dairy animals in the composition and structure of its ...protein components, which give it unique properties. The bioactivity and functionality of whole dromedary milk proteins and their enzymatic hydrolysates have not received much attention, hence this study aims to investigate the effect of enzymatic hydrolysis of dromedary milk proteins on their antioxidant activities and functional properties.
Dromedary milk proteins were treated using four proteolytic enzymes (pepsin, trypsin, α-chymotrypsin and papain) and two mixtures of enzymes (pancreatin and pronase). The degree of hydrolysis was measured to verify the hydrolysis of the proteins. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration chromatography served to determine the molecular mass distribution of the hydrolysates while reversed phase-high performance liquid chromatography (RP-HPLC) was conducted to explore their hydrophobicity. The antioxidant activities were evaluated using various
tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid
ABTS) radical scavenging capacities, iron(III) reducing ability and chelating activity. Besides, functional properties such as solubility, foaming and emulsification were assessed.
Dromedary milk protein hydrolysates exhibited different degrees of hydrolysis ranging from 17.69 to 41.86%. Apart from that, the hydrolysates showed different electrophoretic patterns, molecular mass distribution and RP-HPLC profiles demonstrating the heterogeneity of the resulting peptides in terms of molecular mass and polarity. The hydrolysates displayed significantly higher antioxidant capacities than the undigested proteins at all the tested concentrations. Iron(II) chelating activity was the most improved assay after proteolysis and the hydrolysate generated with pancreatin had the highest chelating power. Dromedary milk protein hydrolysates possessed good solubility (>89%). Further, foaming and emulsifying properties of dromedary milk proteins were enhanced after their proteolysis. These interfacial properties were influenced by the enzymes employed during proteolysis.
Enzymatic hydrolysis of dromedary milk proteins is an effective tool to obtain protein hydrolysates with great antioxidant and functional properties. These results suggest that dromedary milk protein hydrolysates could be used as a natural source of antioxidant peptides to formulate functional foods and nutraceuticals.
Camel milk industrialization faces technological problems related to the presence of colostrum in milk. The determination of color parameters may serve to differentiate between colostrum and milk. ...This work aimed to study the relationship between the chemical composition of camel colostrum and milk and their colors. Samples of colostrum were collected at 2, 12, 24, 48, 72, 96, 120, 144, 168, and 360 h postpartum (
= 16), and their physicochemical properties (pH, acidity, viscosity, color, dry matter, ash, protein, and fat) were analyzed. The results show that all the components decreased during the first 3 days except fat. The content of this later increased from zero in the three sampling on the first day (2, 12, and 24 h) to 1.92 ± 0.61% at 48 h postpartum. The amount of total dry matter and protein decreased from 20.95 ± 3.63% and 17.43 ± 4.28% to 13.05 ± 0.81% and 3.71 ± 0.46%, respectively, during the first 7 days postpartum. There was a weak correlation between the brightness (
) of the camel milk and its contents of dry matter, protein, and fat; however, these parameters were strongly correlated with redness (
) and yellowness (
). Ash content was poorly correlated with the color parameters. Hence, the measurement of the color parameters of camel colostrum and milk can be a new tool to evaluate their quality.
Traditional sun-dried merguez is an authentic Tunisian dried sausage made with a large number of spices and herbs, which was reformulated in this study with camel meat and hump fat and dried as in ...the artisanal process. This research studied the physicochemical, microbiological, and chemical compositional changes that occurred in fresh camel merguez (FCM) after 12 days of drying to achieve traditional dried camel merguez (DCM). The results showed significant weight loss (54.1%), as well as significant decreases in pH (5.20-4.97), moisture (60.5-12.3%), and water activity (0.986-0.673). These results and the acceptable microbiological quality of DCM can explain the safety of traditionally practiced long-term storage at room temperature. All chemical compositions increased upon drying. The composition of DCM included several organic acids, mainly lactate (2820 mg.kg
); diverse unsaturated fatty acids, in particular oleic acid (33.2%); and various minerals, specifically iron (8 mg per 100 g), in addition to volatile compounds impacted by herbs and spices rich in terpenes (56.3%). These results can be useful for investing in indigenous products and promoting the exploitation of camel meat.
This study aimed to determine the physicochemical properties and antioxidant activities of dromedary skim colostrum and milk powder produced by freeze-drying. Results of the study showed that skim ...colostrum powder possessed higher protein content compared to milk powder whereas this latter had greater lactose and ash content. The analysis of mineral content revealed that calcium and magnesium levels were higher in skim colostrum powder while the iron level did not differ significantly between skim colostrum and milk powder. The measurements of colour characteristics indicated that dromedary skim colostrum powder was redder, but less yellow and white than dromedary skim milk powder. Further, dromedary skim milk powder had higher bulk density and tapped bulk density. Protein solubility of skim colostrum powder exceeded that of skim milk powder over a wide range of pH (3-8). The antioxidant activities were evaluated using various in vitro tests, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activities, ferric reducing power assay and ferrous chelating activity. Both dromedary skim colostrum and milk powder exhibited antioxidant activities in a dose dependent manner. DPPH and ABTS radical scavenging activities were almost similar for skim colostrum and milk powder whereas ferric reducing power and ferrous chelating activity were more pronounced in dromedary skim colostrum powder whatever the concentration tested. Hence, freeze-drying process could be used as an effective tool for producing powder from dromedary skim colostrum and milk with nutritional and antioxidant properties.
Comparative study of functional properties, radical scavenging and antimicrobial activities of dromedary whey protein and casein hydrolysates was investigated. Dromedary protein hydrolysates were ...prepared by treatment with digestive proteases (pepsin and pancreatin) and by the proteolytic system of two lactic acid bacteria (
Streptococcus thermophilus
and
Lactobacillus bulgaricus
). Solubility and interfacial properties like emulsifying capacity are improved after enzymatic hydrolysis of both whey protein and casein. Whereas, foam capacity and stability are more important in whey protein hydrolysates than casein hydrolysates and are widely influenced by the method of hydrolysis. All hydrolysates showed radical scavenging activities. The highest antioxidant activity is exhibited by WPHE (whey protein hydrolysated by gastro-intestinal enzymes “pepsin and pancreatin”) for DPPH (2,2-diphenyl-1-picrylhydrazyl) test and CNHE (casein hydrolysated by pepsin and pancreatin) for ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay. Further, whey protein hydrolysates displayed antibacterial activity and WPHE was the most effective, particularly against
Escherichia coli
and
Staphylococcus epidermidis
. Based on the results, we conclude that WPHE has great technological applicability in food ingredients, as a promising source of functional hydrolysate with antioxidant and antimicrobial activities. For this reason, WPHE was added to the dromedary milk based beverage and chemical, microbiological and sensory properties of the resulting product were investigated. Formulated beverage flavored with strawberry or banana possessed a good microbiological quality. The sensory analysis demonstrated a good acceptance mainly in taste and consistency of the beverage samples. There is only significant difference in the color of the different formulated beverages.
Fermented goat milk is an artisanal beverage with excellent nutritional properties. There are limited data on its physicochemical properties, fatty acids, phenolic acids, and on any insight on ...microbiota. The aim of this research was to conduct a pilot study to compare these parameters in raw cow and goat milk before and after spontaneous fermentation in a clay pot and glass container at 37 °C for 24 h. Both types of milk and fermentation containers significantly affected the pH, acidity, proximate composition, viscosity, and whiteness index of fermented milks. A total of 17 fatty acids were identified in fermented milks, where palmitic, stearic, and myristic were the main saturated acids, and oleic and linoleic acids were the main unsaturated ones. These profiles were primarily influenced by the type of raw milk used. Three to five phenolic acids were identified in fermented milks, where quinic acid was the major phenolic compound, and salviolinic acid was identified only in raw goat milk. Preliminary metataxonomic sequencing analysis showed that the genera
spp. and
spp. were part of the microbiota of both fermented milks, with the first genus being the most abundant in fermented goat milk, and
in cow's milk. Moreover,
abundance was negatively correlated with the abundance of many genera, including
. Overall, the results of this pilot study showed significant variations between the physicochemical properties, the fatty and phenolic acids, and the microbial communities of goat and cow fermented milk, showing the opportunity to further investigate the tested parameters in fermented goat milk to promote its production.
Date seeds (DS) are one of the major waste of date processing plants and have vital therapeutic properties. It represents an inexhaustible source of dietary fiber and bioactive compounds. Roasting ...could be an essential process in ensuring that this date by-product is used. Due to functional properties of roasted date seeds and the high consumption rate of yogurt, the fortification of these products is a novel track for the revalorization of date by-products and the development of a functional and bioactive yogurt, which is of practical industrial importance. The effects of roasted DS supplementation (1, 2 and 3%) in goat and cow yogurt formulation were assessed in order to develop a new functional yogurt. The analysis of the basic nutritional composition revealed that the roasted DS powder was rich in soluble fiber (42.29 ± 3.41 g.100 g
−1
) and characterized by excellent techno-functional properties (especially water-holding and swelling capacities). In terms of mineral content, roasted DS powder contained high levels Ca (354.0 ± 6.0 mg 100 g
−1
DW), Mg (63.1 ± 0.6 mg 100 g
−1
DW) and Fe (17.2 ± 1.4 mg 100 g
−1
DW). Phenolic compounds detected in roasted DS included epicatechin, catechin ( + ) and quinic acid as dominant ones among 19 types. Thanks to its good DPPH•-radical scavenging activity (IC
50
= 0.04 mg ml
−1
) and its dark color (L* = 53.29 ± 0.07), roasted DS powder served as natural and anti-oxidant agent in formulated yogurt. The 3% DS-fortified yogurts (goat and cow) presented the lowest moisture (81.23 ± 1.95 and 79.38 ± 1.02 g 100 g
−1
for goat and cow yogurt, respectively) and the highest in protein content (3.76 ± 0.16 and 2.92 ± 0.81 g 100 g
−1
for goat and cow yogurt, respectively). Interestingly, fortified goat and cow yogurts with 3% of roasted DS recovered 58.5%, and 96.11% of recommended dietary allowances in Mg and Fe, respectively. Rising levels of roasted DS powder into goat and cow yogurts increased viscosity, water holding capacity and antioxidant capacity, and decreased syneresis. LC-ESI-MS-analysis, revealed the presence of new phenolic compounds in fortified yogurts and the disappearance of some other despite their existence in roasted DS. Sensory evaluation showed that yogurts fortification with roasted DS powder weakened greatly the goaty flavor.
The antioxidant and the lipase and the angiotensin‐converting enzyme (ACE) inhibitory properties of camel lactoferrin and its hydrolysates elaborated with four proteolytic enzymes (trypsin, ...α‐chymotrypsin, pancreatin and papain) were assessed. Lactoferrin was purified from camel colostrum using cation exchange chromatography. Camel lactoferrin hydrolysates showed different degrees of hydrolysis, reverse phase‐HPLC profiles and molecular weight distributions, reflecting heterogeneity in terms of polarity and molecular weight of the generated peptides. Camel lactoferrin hydrolysates exhibited higher antioxidant, lipase and ACE inhibitory activities than native lactoferrin. Pancreatin‐generated hydrolysates showed the highest lipase inhibitory activity (48.1%), while papain‐generated hydrolysates presented the greatest ACE inhibitory activity (89.14%).
Biological activities of camel lactoferrin and its enzymatic hydrolysates.
The aim of this study was to explore the antibacterial peptides derived from dromedary lactoferrin (LFc). The LFc was purified from colostrum using a batch procedure with a cation exchange ...chromatography support and was hydrolyzed with pepsin to generate peptic digest. This peptic digest was fractionated by cation exchange chromatography, and the antilisterial activity of LFc, peptic digest, and obtained fractions was investigated using the bioscreen method. The growth of Listeria innocua ATCC 33090 and LRGIA 01 strains was not inhibited by LFc and its hydrolysates. Two fractions of dromedary lactoferrin peptic hydrolysate were active against both strains. A tandem mass spectroscopy analysis revealed that the 2 active fractions comprised at least 227 different peptides. Among these peptides, 9 found in the first fraction had at least 50% similarity with 10 known antimicrobial peptides (following sequence alignments with the antimicrobial peptide database from the University of Nebraska Medical Center, Omaha). Whereas 9 of these peptides presented homology with honeybee, frog, or amphibian peptides, the 10th peptide, F152SASCVPCVDGKEYPNLCQLCAGTGENKCACSSQEPYFGY192 (specifically found in 1 separated fraction), exibited 54% homology with a synthetic antibacterial peptide (AP00481) derived from human lactoferrin named kaliocin-1. Similarly, the second fraction contained 1 peptide similar to lactoferrampin B, an antibacterial peptide derived from bovine milk. This result suggests that peptic hydrolysis of LFc releases more active antimicrobial peptides than their protein source and thus provides an opportunity for their potential use to improve food safety by inhibiting undesirable and spoilage bacteria.