Arbutus unedo fruit syrup as a fortifying agent: effect on physicochemical, microbiological, rheological, sensory and antioxidant properties of yoghurt.

This study aims to assess the antioxidant and the antibacterial activities of Arbutus unedo fruits and to valorize its syrup by the incorporation in bi-layer yoghurt. The antioxidant activity of the ethanol 80% fruits and syrup extracts was evaluated by three methods namely DPPH·, ABTS·+ and FRAP. The antibacterial activity was tested against seven pathogenic bacteria using agar well diffusion method. The yoghurt was prepared using 10 and 20% layers of A. unedo syrup, physicochemical, rheological, microbiological and sensorial characteristics and the antioxidant activity were investigated during cold storage. The results revealed that the heat treatment decreased the phenolic compounds contents and the antioxidant activity in the syrup extract. Both fruits and syrup extracts demonstrated an antibacterial activity against the tested bacteria. The highest inhibition diameter (40 mm) was recorded for Aeromonas hydrophila at 100 mg/mL of fruit echtanolic extract. The prepared bi-layer yoghurts showed stability for the physicochemical and microbiological properties during storage. The rheological properties revealed that the A. unedo syrup increases the yoghurt consistency (k). The antioxidant activity of the yoghurt indicated that fermentation improved the radical scavenging power of the A. unedo syrup at the beginning and the activity decreased slowly during storage. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05801-4.

Microwave and Roasting Impact on Pumpkin Seed Oil and Its Application in Full-Fat Mayonnaise Formula.

In this study, 'Béjaoui' Cucurbita maxima seeds variety were exposed to both microwave and roasting prior to oil cold press extraction. In addition, full-fat mayonnaise formula from untreated and treated pumpkin seed oils was prepared and assessed for their physical stabilities and bioactive properties in 28-day storage at 25 ± 1 °C. A mayonnaise sample prepared with unrefined sunflower seed oil served as a control. The results showed that the microwave pretreatment of seeds greatly enhanced the oxidative stability of the pumpkin seed oil, which increased from 3 h 46 min ± 10 min in the untreated sample to 4 h 32 min ± 14 min in the microwave cold press pumpkin seed oil. The sterol content increased from 4735 ± 236.75 mg/kg oil in the untreated cold press pumpkin seed oil to 5989 ± 299.45 mg/kg oil and 7156 ± 357.8 mg/kg in the microwave cold press pumpkin seed oil and the roasted cold press pumpkin seed oil, respectively. The mayonnaise prepared with microwave cold press pumpkin seed oil exhibited the lowest creaming index and was more stable to droplet growth when compared to the other mayonnaise samples. All mayonnaise samples prepared with pumpkin seed oils exhibited higher total phenolic contents and antioxidant activities during storage when compared to the mayonnaise sample prepared with unrefined sunflower seed oil. Among pumpkin seed oil mayonnaise samples, the highest values were, however, observed in the one prepared with microwave cold press pumpkin seed oil. Thanks to its high nutraceuticals, the latter could be confidently regarded as a natural fat substitute for commercial stable vegetable oils mayonnaise type emulsions.

Cytoprotective activities of representative nutrients from the Mediterranean diet and of Mediterranean oils against 7-ketocholesterol- and 7ß-hydroxycholesterol-induced cytotoxicity: Application to age-related diseases and civilization diseases.

7-ketocholesterol and 7ß-hydroxycholesterol are two oxysterols mainly formed by the autoxidation of cholesterol. These two molecules are interconvertible via specific enzymes. These two oxysterols are often observed at increased amounts in biological fluids as well as tissues and organs affected during age-related diseases and in diseases of civilization such as cardiovascular, neurodegenerative, and ocular diseases as well as type 2 diabetes and metabolic syndrome. Noteworthy, 7-ketocholesterol and 7ß-hydroxycholesterol induce oxidative stress and inflammation, which are frequently observed in patients with age-related and civilization diseases. For this reason, the involvement of these two oxysterols in the pathophysiology of these diseases is widely suspected. In addition, the toxicity of these oxysterols can lead to death by oxiapoptophagy characterized by oxidative stress, apoptosis induction and autophagy criteria. To prevent, or even treat, certain age-related or civilization diseases associated with increased levels of 7-ketocholesterol and 7ß-hydroxycholesterol, the identification of molecules or mixtures of molecules attenuating or inhibiting the toxic effects of these oxysterols allows to consider new treatments. In this context, many nutrients present in significant amounts in the Mediterranean diet, especially tocopherols, fatty acids, and polyphenols, have shown cytoprotective activities as well as several Mediterranean oils (argan and olive oils, milk thistle seed oil, and pistacia lentiscus seed oil). Consequently, a nutraceutical approach, rich in nutrients present in the Mediterranean diet, could thus make it possible to counteract certain age-related and civilization diseases associated with increased levels of 7-ketocholesterol and 7ß-hydroxycholesterol.

Encapsulation of Tunisian thyme essential oil in O/W nanoemulsions: Application for meat preservation.

This study aims to optimize the preparation of thyme essential oil nanoemulsion using a ternary mixture design based on the following three components: chitosan, gum Arabic and median-chain triacyglycerols (MCT). The results showed that the formulation which contained 40% chitosan, 40% gum Arabicand 20% of MCT led to a stable nanoemulsion within 30 days of storage at 4 °C. Indeed, the observed mean diameter (d[4,3]) and the polydispersity index (PDI) are the lowest with a ζ-potential value greater than +30 mV. Moreover, the amount of thyme essential oil dissolved in MCT was optimized and the 2% (w/w) was selected to prepare O/W nanoemulsion for preserving meat products. Besides, the obtained data of the chemical characteristics of meat products demonstrated that the pH, TVNB, TBARS, shear strength increased slightly and insignificantly with storage time at 4 °C.However, there was a difference between control and sample treated with nanoemulsionsin terms of physicochemical characteristics.

Exploring potential new galactomannan source of Retama reatam seeds for food, cosmetic and pharmaceuticals: Characterization and physical, emulsifying and antidiabetic properties.

In 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 (Tg) and melting temperature (Tm) 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.

Pelargonium graveolens Aqueous Decoction: A New Water-Soluble Polysaccharide and Antioxidant-Rich Extract.

BACKGROUND: The decoction of Pelargonium graveolens yields an antioxidant-rich extract and a water-soluble polysaccharide. This study aims (1) to investigate the effect of process parameters (extraction time and temperature) on the antioxidant activity of the decoction and the extraction yield of CPGP by response methodology and (2) to study the chemical properties of the optimized decoction and rheological properties of the corresponding extracted polysaccharide. RESULTS: The antioxidant-rich decoction contained about 19.76 ± 0.41 mg RE/g DM of flavonoids and 5.31 ± 0.56 mg CE/gDM of condensed tannins. The crude Pelargonium graveolens polysaccharide (CPGP) contained 87.27 % of sugar. Furthermore, the CPGP solutions (0.5%, 1%, and 2%) exhibited shear-thinning or pseudoplastic flow behavior. A central composite design (CDD) was applied to assess the effects of temperature and time on the antioxidant activity of the decoction, on the one hand, and on water-soluble polysaccharide yield, on the other. The decoction optimization of Pelargonium graveolens aimed to use less energy (93°C for 11 minutes) leading to the highest values of decoction phenolic content (33.01 ±0.49 mg GAE/gDM) and DPPH scavenging activity (136.10 ± 0.62 mg TXE/gDM) and the highest values of CPGP yield (6.97%). CONCLUSION: The obtained results suggest that the CPGP rheological characteristics are suitable for applications in many industries, especially food. The values of optimal conditions showed that Pelargonium graveolens decoction operation could have multiple uses, especially for consuming less energy.

Effectiveness of almond gum trees exudate as a novel edible coating for improving postharvest quality of tomato (Solanum lycopersicum L.) fruits.

The use of coatings is a technique used to increase postharvest life of the fruit. Almond gum exudate was used, in comparison with gum arabic, at concentrations of 10% as a novel edible coating, to preserve the quality parameters of tomato (Solanumlycopersicum). Fruits were harvested at the mature-green stage of ripening. Results showed that the coatings delayed significantly (p < 0.05) the changes in color, weight loss, firmness, titratable acidity, ascorbic acid content, soluble solids concentration, and decay percentage compared to uncoated control fruits. Sensory evaluation proved the efficacy of 10% almond gum and gum arabic coatings to maintain the overall quality of tomato fruits during storage period (20 days). In addition, the difference between gum arabic and almond gum coatings was not significant (p > 0.05) except for pulp color. Therefore, we can suggest the use of almond gum exudate as a novel edible coating extends the shelf-life of tomato fruits on postharvest.

Pumpkin (Cucurbita maxima) seed proteins: sequential extraction processing and fraction characterization.

Seed proteins extracted from Tunisian pumpkin seeds ( Cucurbita maxima ) were investigated for their solubility properties and sequentially extracted according to the Osborne procedure. The solubility of pumpkin proteins from seed flour was greatly influenced by pH changes and ionic strength, with higher values in the alkaline pH regions. It also depends on the seed defatting solvent. Protein solubility was decreased by using chloroform/methanol (CM) for lipid extraction instead of pentane (P). On the basis of differential solubility fractionation and depending on the defatting method, the alkali extract (AE) was the major fraction (42.1 (P), 22.3% (CM)) compared to the salt extract (8.6 (P), 7.5% (CM)). In salt, alkali, and isopropanol extracts, all essential amino acids with the exceptions of threonine and lysine met the minimum requirements for preschool children (FAO/WHO/UNU). The denaturation temperatures were 96.6 and 93.4 °C for salt and alkali extracts, respectively. Pumpkin protein extracts with unique protein profiles and higher denaturation temperatures could impart novel characteristics when used as food ingredients.

The influence of season on the gonad index and biochemical composition of the sea urchin Paracentrotus lividus from the Golf of Tunis.

Seasonal variation in the gonad weight and biochemical composition of the sea urchin Paracentrotus lividus from the Golf of Tunis (Tunisia) were studied between September 2003 and August 2004. The highest gonad indices occurred in March (16.71%). The spawning period occurred between April and July and resulted in a fall in gonad indices to low level (7.12 ± 0.12%). Protein constituted the main component of the gonad, and lipid and carbohydrate were found at appreciable amounts. Consistent with the gonad cycle, sea urchin biochemical components showed clear seasonal variation with a significant decrease during the spawning period. The polyunsaturated fatty acid (PUFA) group was found at high level (40% of the total fatty acids). Of the PUFA group, eicosapentaenoic (C20:5 n - 3) and eicosatetraenoic (C20:4 n - 3) were the most abundant gonadal lipids. The level of PUFA was significantly affected by temperature variation showing an increase during the cold months and a decrease in the hot months.

Nutritional composition of Zizyphus lotus L. seeds.

BACKGROUND: 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. ß-Tocopherol was the major tocopherol (130.47 mg 100 g(-1) ). This oil was rich in Δ7-campestrol and ß-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.