34 research outputs found
Optimization of the Extraction Process by Response Surface Methodology of Protein Isolate from Defatted Jujube (Zizyphus lotus L.) Seeds
No full textIn this study, response surface methodology, based on Box-Behnken design, was used to optimize the extraction conditions of protein isolate from the defatted seeds of jujube (Zizyphus lotus L.). This research focused on the effect of extraction temperature (30–50 °C), mixing time (15–75 min), pH (6.0–10.0), and solvent to solid ratio (15:1–35:1 v/w) on the extraction yield of jujube seed (Z. lotus L.) protein. The pH, mixing time and extraction temperature were the most significant (p < 0.01) factors affecting the yield of Z. lotus protein isolate. The optimum conditions were as follows: extraction temperature 41.79 °C, mixing time 54.46 min, pH 8.65, and solvent to solid ratio of 25.90:1. Under these conditions, the experimental percentage value was 81.52%, which is well in close agreement with the value predicted by the model (80.91%). The results of physicochemical analysis showed that protein isolate of Z. lotus ZLPI had most of the essential amino acids and hence could be considered as a high quality protein. Protein isolate from Z. lotus had a single denaturation temperature (120.17 °C), while soy protein isolate had two denaturation temperatures (76.36 and 93.02 °C). This fact is of great economic interest due to several applications of Z. lotus protein in the food pharmaceutical and cosmetic industries
Classification of Southern Tunisian honeys based on their physicochemical and textural properties
No full textThis study investigated the physicochemical, rheological and textural properties of nine types of honey from different regions of southern Tunisia. Principal component and cluster analyses were used to classify the honeys into groups. The physicochemical results (water, proteins, total soluble solids, pH, free acidity, water activity, electrical conductivity, invertase activity, Hydroxymethylfurfural (HMF), vitamin C, lycopene and anthocyanins) were in accordance with those of the standards Established by the Codex Alimentarius. The invertase activity varied from 62.58 units/kg to 110.24 units/kg. The HMF values of the different types of honey ranged from 11.48 mg/kg in prickly pear honey to 25.56mg/kg in heather honey. Anthocyanin contents, lycopene and vitamin C contents ranged between 8.38 and 24.86 μg/L, 1.08 to 6.17 mg/kg and 30.71 to 129.38 mg/kg, respectively. The flow test confirmed the Newtonian behavior of all honeys, and their textural properties had very high extrusion forces varying from 113.50 g to 131.05 g. Cluster analysis (CA) and the biplot generated through PCA recognized four groups of honeys based on either the physicochemical parameters or textural attributes and only three groups based on color and sugar
Chemical characteristics and compositions of red pepper seed oils extracted by different methods
No full textThe present work was undertaken to study the physicochemical characteristics, fatty acid, phenolic and tocopherol compositions as well as the antioxidant activities of red pepper seed oils extracted using different methods (soxhlet, cold-pressing, supercritical-CO2 and microwave-assisted extraction process). The results showed that the red pepper seeds were (on a dry-weight basis): ash 3.05%, water 6.63%, oil 18.39%, protein 28.33%, and total carbohydrate 43.60%. In addition, the results revealed that the predominant fatty acids were linoleic, palmitic and oleic acids. The highest and lowest contents of linoleic acid (76.54%) were found in microwave-assisted (76.54%) and soxhlet (73.65%) extracted pepper seed oils, respectively. < Gamma>-tocopherol was the main tocopherol at 278.65 mg/100 g seed oil, followed by < alpha>-tocopherol and < delta>-tocopherol. Nevertheless, high content in total tocopherols was found in microwave extracted red pepper seed oils. The lowest and highest values of oxidative stability were 1.25 and 11.26 h for soxhlet and microwave-assisted extracted seed oils, respectively. Overall, the high antioxidant activities of microwave-assisted extracted seed oil suggest that it could be economically used as valuable natural products for industrial, cosmetic, and pharmaceutical utilizations
Physicochemical, rheological, and thermal properties of six types of honey from various floral origins in Tunisia
No full textExploring potential new galactomannan source of Retama reatam seeds for food, cosmetic and pharmaceuticals: Characterization and physical, emulsifying and antidiabetic properties
No full textIn this study, physicochemical, interfacial and emulsifying properties of Retama reatam and guar galactomannans were comparatively investigated. The results showed that Retama reatam galactomannan is mainly composed of total carbohydrates (95.52%) and lower protein contents (0.87%). The sugars identified were mannose (Man) and galactose (Gal), with a Man:Gal ratio of 1.85 compared to guar gum (1.83). The results of thermal properties indicated were transition temperature (T g ) and melting temperature (T m ) very similar to those of the guar gum. Moreover, results also revealed that there is no significant difference in terms of equilibrium interfacial tension of Retama reatam gum at 10 and 20 °C. Moreover, preliminary tests show that stable oil-in-water nanoemulsions may be formulated using Retama reatam gum. Therefore, measurement of mean oil droplet diameter d after heating at 80 °C, shows that stable nanoemulsions may be formulated using Retama reatam galactomannan. Further in vivo experiments confirmed that Retama reatam gum can reduce the glycemic index of starchy foods and inhibit the surge of postprandial blood glucose level
PHYSICOCHEMICAL CHARACTERISTICS AND ANTIOXIDANT ACTIVITIES OF ZIZYPHUS LOTUS L. SEED OIL
No full textThis study was designed to examine both the chemical composition as well as the antioxidant activities of the seed oil extracted from Zizyphus lotus L. The results showed that the neutral lipids were mainly composed of triacylglycerols (92.75% of total lipids). Phosphatidylcholine and digalactosyldiacylglycerol were the main phospholipid and glycolipid subclasses, respectively. Oleic, linoleic and palmitic acids were the major fatty acids in the lipids of Z. lotus seeds. In addition, b-tocopherol was the predominant tocol at 122.13 mg/100 g seed oil, which was equivalent to 60.41% of the total tocols followed by d-tocopherol (13.30%) and d-tocotrienol (8.95%). The total phenol and flavonoid contents were 18.45 mg/100 g and 2.31 QE/g oil, respectively, with ferulic acid as the main phenolic acid (1.36 mg/100 g oil). Overall, the strong antioxidant activities suggest that it could be advantageously used as a functional or nutraceutical food in order to prevent or moderate oxidative stress-related diseases
Nutritional composition of Zizyphus lotus L. seeds
No full textBACKGROUND: Zizyphus lotus seeds are an unutilized source of vegetable oil and protein and nothing has been reported on their physicochemical characteristics which would indicate the potential uses of these seeds.
RESULTS: The percentage composition of the Zizyphus lotus seeds is (on a dry-weight basis): ash 1.05%, oil 32.92%, protein 19.11%, total carbohydrate 40.87% and moisture 6.05%. Calcium, potassium and magnesium constitute the major minerals of Zizyphus lotus seeds. The seed proteins are rich in threonine, glutamic acid, leucine, arginine and aspartic acid (26.73%, 17.28%, 13.11%, 9.47% and 7.76%, respectively). The main fatty acids of the oil are oleic (61.93%), linoleic (18.31%) and palmitic (9.14%) acids. Glycerol trioleate (OOO; O: oleic acid) was the most abundant triacylglycerol, representing 26.48% of the total triacyglycerols. beta-Tocopherolwas themajor tocopherol (130.47 mg100 g(-1)). This oilwas rich in Delta 7-campestrol and beta-sitosterol (147.82 and 82.10 mg 100 g(-1) oil), respectively.
CONCLUSION: Zizyphus lotus seeds are rich in fat and protein which are of potential industrial significance. In addition, Zizyphus lotus L. seed oil contained many bioactive compounds. This fact is of great economic interest owing to several applications of Zizyphus lotus L. seeds in the food, cosmetics and medicinal industries
Physicochemical and bioactive properties of six honey samples from various floral origins from Tunisia
No full textThe present study was undertaken to determine the physicochemical, biochemical, and antioxidant activities of Tunisian honey samples. All the extracted honey samples appeared to conform to the European Legislation (EC Directive 2001/110) for all parameters. Mint honey, for instance, possesses significant pH value (p < 0.05), invertase activity, water, and protein contents. In addition, this study demonstrates that the color of the Tunisian honeys is highly variable and ranges from pale yellow to dark brown. The total phenolic, flavonoid and carotenoid contents significantly vary (. p < 0.05). The highest values were found in mint honey, which has a very dark color. Correlations between the analyzed parameters are statistically significant (p < 0.05). The DPPH radical scavenging activity of rosemary honey was determined as lower (p < 0.05) than the other analyzed honey samples. Yet, the highest activity was detected in mint honey. The results suggest that Tunisian honeys could be beneficially used as a functional or nutraceutical substance as they prevent or moderate oxidative stress-related diseases
Comparative study of Acacia tortilis subsp. raddiana gum of Tunisian origin and commercial Acacia senegal gum
No full textInternational audienceThis study aimed to assess the physicochemical and functional properties of Tunisian Acacia tortilis subsp. raddiana gum (TAG) and commercial Acacia Senegal gum (CAG). Therefore, the results indicated that water and protein were 11.79 and 11.58%, 4.38 and 1.35%, respectively. Interestingly, the main sugar compositions of two Acacia gums were arabinose and galactose. In addition, the FT-MIR spectra of the gum samples demonstrated a typical trend of the tested exudate gums.Hence, Tunisian and commercial Acacia gums showed shear-thinning flow behavior at different pH and heating temperatures.In addition, the findings revealed that the Cross model was the best model to describe the rheological behavior of the two gums (TAG and CAG). Moreover, the 1H and 13C NMR spectra of two tested gums confirmed the presence of arabinogalactan structure. Besides, the microstructure of the two gums demonstrated a semi-crystalline with a more amorphous material.Therefore, the physicochemical, rheological, and functional characterization indicated that Tunisian Acacia gum (TAG)could be used in food industries as an emulsifier, gelling and thickeners agents
