Effect of stage of lactation on the physical and chemical composition of Drâa goat milk

Raw milk characterization constitutes a preliminary and an important step to take account in order to obtain an optimal technological valorization. Among other factors, breed, feed and stage of lactation are the most important factors that influenced cheese making and other dairy products valorization. Thus, this study proposes to analyze the physicochemical composition of Drâa goat milk and to study raw milk fluctuations throughout a complete lactation period. The study was carried out in the Experimental Station of Errachidia (Southern Morocco). In this context, sixteen goats were selected and sampled every week during a period of 160 days (average lactation length). A total of 128 samples of raw goat milk were analyzed according to international standards. Analyses were focused to determination of pH, acidity, density, Dry Matter (DM), Solids Non Fat (SNF), ash, fat and Total Nitrogenous Matter (TNM). Average values were about 17.8°D for acidity, 13.3% for Dry Matter, 0.73% for ash, 4.16% for fat and 3.60% for Total Nitrogenous Matter. In general, theses values are largely situated in the upper level of the range suggested by several Moroccan and foreign researchers for other goat species. On the other hand, the evolution of physical and chemical parameters throughout  lactation stages showed that dry matter, fat content and total nitrogenous matter increased significantly throughout the lactation period; the opposite was found for density (p<0.001). No significant (p>0.05) changes were shown for milk acidity and the average found was around 17°D. Content of milk ash increased significantly during the late lactation stage compared to the earliest and the opposite was observed for pH.The results of the  present investigation show that Drâa goat milk is rich with desirable  components like fat and protein for dairy product manufacturers, and that the late lactation stage seems to be the best period to ensure an optimum technological valorization.Key words: Goat, Morocco, milk, physicochemical, lactatio

Seasonal variation in yield and chemical composition of Moroccan Thymbra capitata (L.) Cav. essential oil and its corresponding hydrolat extracted essential oil

The aim of the present work was to study the variation in yield and chemical composition of the pure essential oil (EO) and essential oil dissolved in its corresponding hydrolat (HEO) of Thymbra capitata (L.) Cav. of Morocco according to its stage of growth. The results obtained revealed that the yield of essential oil increases with the growth of the plant to reach its maximum at post-flowering stage (2.90%). On the other hand, the yield of dissolved essential oil in the corresponding hydrolats peaked at the flowering stage (0.53%) and then dropped. The analysis of these oils was performed by the GC-MS and showed that carvacrol was the major compound of this plant during its growth stage. The highest carvacrol content was noted at the flowering stage for EO (84.26%) and at the pre-flowering stage for HEO (98.54%). However, the evolution of concentration of p-cymene (3.84-6.01%) and g-terpinene (3.45-5.68%) in EO seems to be the opposite of carvacrol. Moreover, these two monoterpene hydrocarbons are absent or almost absent in HEO

Evaluation des critères physiques, physicochimiques et biochimiques et des activités biologiques des graines et des huiles des graines du fenouil (Foeniculum vulgare Mill.)

The fennel is a typical plant of the Mediterranean region used in traditional pharmacopoeia and as an aromatic spice. This study was interested in an evaluation of the physical, physicochemical and biochemical criteria and the biological activities of the seeds and seeds oils of local (beldi) fennel produced at four stages of maturity in four terroirs of Essaouira province (Central West, Morocco), compared to those of a local fennel produced in a neighboring terroir and an imported fennel. Seeds of different maturity stages and geographic origins were clearly differentiated into homogeneous groups according to studied criteria. The water activity of these seeds is between 0.43 and 0.51 with an average ash content of 6.24 g/100 g of dry matter (DM) containing fairly high contents of potassium, calcium, sodium and baryum. Seed total polyphenols recorded interesting levels ranging between 623.64 and 959.24 mg gallic acid equivalent/100 g DM. The antioxidant activity is estimated between 23.53 and 43.83 mg ascorbic acid equivalent/g DM. Yields of vegetable and essential oils varied from 8.55 to 16.28 % and from 1.4 to 2.7 %, respectively. However, the high values recorded for free acidity, peroxide index and specific extinction of vegetable oil indicate that it cannot be considered as edible oil. Concerning the essential oil, significant increases in the aroma compounds s-limonene and fenchone were noted during maturity. Besides, the antibacterial activity tests have shown that Staphylococcus aureus is sensitive to the action of this essential oil. Moreover, the quality criteria of the studied fennel seeds and seed oils showed the influence of the geographical origin. These results would make it possible to propose ways of valorizing, quality control and labeling of beldi fennel under a distinctive sign of origin and quality.Le fenouil est une plante typique de la région méditerranéenne utilisée dans la pharmacopée traditionnelle et comme épice aromatique. Cette étude s’est intéressée à une évaluation des critères physiques, physicochimiques, biochimiques et des activités biologiques des graines et des huiles des graines du fenouil local (beldi) produit à quatre stades de maturité dans quatre terroirs de la province d’Essaouira (Centre-Ouest du Maroc), comparées à celles d’un fenouil local produit dans un terroir limitrophe et d’un fenouil importé. Les graines de stades de maturité et d’origines géographiques différents ont été nettement différenciées dans des groupes homogènes selon les critères étudiés. L’activité de l’eau de ces graines est comprise entre 0,43 et 0,51 avec une teneur moyenne en cendres de 6,24 g/100 g de la matière sèche (MS) renfermant des teneurs assez importantes en potassium, calcium, sodium et baryum. Les polyphénols totaux des graines ont enregistré des teneurs intéressantes variant entre 623,64 et 959,24 mg équivalent acide gallique/100 g MS et l’activité antioxydante de ces graines est estimée entre 23,53 et 43,83 mg équivalent acide ascorbique/g MS. Les rendements en huile végétale et huile essentielle ont varié de 8,55 à 16,28 % et de 1,4 à 2,7 %, respectivement. Toutefois, les valeurs élevées enregistrées pour l’acidité libre, l’indice de peroxyde et l’extinction spécifique de l’huile végétale renseignent qu’elle ne peut être considérée comme une huile alimentaire. Concernant l’huile essentielle, des augmentations significatives des composés d’arôme s-limonène et fenchone ont été notées au cours de la maturité. En outre, les tests de l’activité antibactérienne ont montré que Staphylococcus aureus est sensible à l’action de cette huile essentielle. Par ailleurs, les critères de qualité des graines et des huiles des graines de fenouil étudiés ont montré l’influence de l’origine géographique. Ces résultats permettraient de proposer des voies de valorisation, de contrôle de qualité et de labellisation du fenouil beldi sous un signe distinctif d’origine et de qualité

Optimization and characterization of gelatin and chitosan extracted from fish and shrimp waste

Fish and seafood processing industries generate large quantities of waste which are at the origin of several environmental, economic and social problems. However fish waste could contain high value-added substances such as biopolymers. This work focuses on optimizing the gelatin and chitosan extraction from tilapia fish skins and shrimp shells respectively. The gelatin extraction process was optimized using alkali acid treatment prior to thermal hydrolysis. Three different acids were tested at different concentrations. Chitosan was obtained after acid demineralization followed by simultaneous hydrothermal deproteinization and deacetylation by an alkali treatment with different concentrations of HCl and NaOH. The extracted gelatin and chitosan with the highest yield were characterized by determining their main physicochemical properties (Degree of deacetylation, viscosity, pH, moisture and ash content). Results show a significant influence of the acid type and concentration on the extraction yield of gelatin and chitosan, with an average yield of 12.24% and 3.85% respectively. Furthermore, the obtained physicochemical properties of both extracted gelatin and chitosan were within the recommended standard values of the commercial ones used in the industry

Optimization and characterization of gelatin and chitosan extracted from fish and shrimp waste

Fish and seafood processing industries generate large quantities of waste which are at the origin of several environmental, economic and social problems. However fish waste could contain high value-added substances such as biopolymers. This work focuses on optimizing the gelatin and chitosan extraction from tilapia fish skins and shrimp shells respectively. The gelatin extraction process was optimized using alkali acid treatment prior to thermal hydrolysis. Three different acids were tested at different concentrations. Chitosan was obtained after acid demineralization followed by simultaneous hydrothermal deproteinization and deacetylation by an alkali treatment with different concentrations of HCl and NaOH. The extracted gelatin and chitosan with the highest yield were characterized by determining their main physicochemical properties (Degree of deacetylation, viscosity, pH, moisture and ash content). Results show a significant influence of the acid type and concentration on the extraction yield of gelatin and chitosan, with an average yield of 12.24% and 3.85% respectively. Furthermore, the obtained physicochemical properties of both extracted gelatin and chitosan were within the recommended standard values of the commercial ones used in the industry

Nanotechnology and Plant Extracts as a Future Control Strategy for Meat and Milk Products

Plant extracts, well known for their antibacterial and antioxidant activity, have potential to be widely used preservatives in the food industry as natural alternatives to numerous synthetic additives which have adverse impacts on health and the environment. Most plant compounds and extracts are generally recognized as safe (GRAS). The use of preservatives is of great importance for perishable foods such as meat and milk, which, along with their products, are commonly consumed food items globally. However, the bioavailability of plant compounds could be diminished by their interaction with food components, processing, and storage. Nanoencapsulation of plant extracts, especially essential oils, is an effective method for their application in food model systems. This technique increases the bioactivity of plant compounds by increasing their physical stability and reducing their size, without negative effects on organoleptic properties. Furthermore, a recent study showed that plant extracts act as good bioreductants for biosynthesis of nanoparticles. This so-called green synthesis method using plant extracts is a rapid, relatively inexpensive, safe, and efficient method for synthesis of nanoparticles including silver, gold, iron, lead, copper, cobalt, palladium, platinum, zinc, zinc oxide, titanium oxide, magnetite, and nickel. Some of these nanoparticles have antimicrobial potential which is why they are of great interest to the food industry. In this chapter, the nanoencapsulation of plant extracts and plant extract-mediated synthesis of nanoparticles and their potential application in order to improve the safety and quality and prolong the shelf life of meat and milk products are reviewed and discussed