CHEMICAL AND SENSORY PROPERTIES OF VERJUICE, A TRADITIONAL TURKISH NON-FERMENTED BEVERAGE FROM KABARCIK AND YEDIVEREN GRAPES

Verjuice is an unfermented green grape juice obtained by pressing green grapes. It has a unique flavor and sour taste. In the present study, parameters on the quality properties of verjuice made from Kabarcık and Yediveren grape varieties were studied; turbidity of fresh verjuice samples were 57.3 and 59.57 (625 nm %T), respectively. Phenolic matter contents ranged between 626.27 and 753.80 (mg/100 mL). In the samples treated with heat, clarified with gelatin and stored at 4C, the turbidity values were 81.20 and 93.10 (625 %T), and the total phenolic matter contents were 270.21 and 227.48 mg/100 mL in Kabarcık and Yediveren varieties, respectively. In addition, according to sensory evaluation, verjuice samples clarified with gelatin were preferred most by the panelists.

PRACTICAL APPLICATIONS

Verjuice is an unfermented green grape juice obtained by pressing unripe grapes with a unique flavor and sour taste. It is traditionally produced by pressing grapes and sieving the juice obtained through a nonmetal. It is preserved in bottles, adding olive oil to prevent contact with air, at cool condition. It is consumed locally, especially in the Mediterranean and southeastern regions of Turkey, to enhance the flavor of traditional meals, salads and appetizers, and as an ingredient in the production of various drinks, and several sausages such as mustard sausage. The natural verjuice that is neither clarified nor heated was more flavored, but it is turbid and has rather short shelf life. The present study revealed that clarification with gelatin followed by heat treatment of bottled verjuice at 85C for 15 min result in a favorable product with respect to quality properties during shelf life at ambient temperature.     

A comparison of the physicochemical, microbiological and aromatic composition of Traditional and Industrial Leben in Tunisia

Traditional Tunisian Leben (TL) was produced according to the traditional method. Physicochemical and microbiological characteristics and major aromatic compounds were studied and compared to industrial Leben (IL) and experimental Leben (EL). The results show a decrease in lactose content and pH value and an increase in lactic acid during spontaneous fermentation. TL and EL were characterised by higher protein, lactose and ash contents but were less fatty and acidic than IL. Lactic acid bacteria (LAB) and yeasts present in TL were responsible for lactic acid fermentation and aroma development. The LAB and yeast counts in TL were higher than that in EL and IL. Dynamic headspace extraction procedure shows the existence of four major volatile compounds: acetaldehyde, ethanol, diacetyl and acetoin in TL, IL and EL. However, TL has the most important quantity of aroma.     

VARIATIONS IN ESSENTIAL OIL COMPOSITION DURING MATURATION OF CORIANDER (CORIANDRUM SATIVUM L.) FRUITS

The composition of volatile components of the essential oils extracted from fruits of coriander ( Coriandrum sativum L.) at four stages of maturity was studied by gas chromatography–flame ionization detector and gas chromatography-mass spectrometry. Essential oil yields showed marked increase during maturation process and 41 compounds were identified. Linalool was the main compound in all ripening stage amounting from 36.69 to 72.35%. Geranyl acetate (35.17%), β-caryophyllene (3.47%) and borneol (3.26%) were the main compounds at the first stage of maturity (immature fruits). At the second stage, geranyl acetate (8.21%), camphor (4.01%) and menthol (2.96%) were reported as the main constituents. In the third stage, geranyl acetate (20.66%), α-humulene (5.44%) and limonene (1.68%) were the main compounds. At the final stage of maturity (mature fruits), essential oil consist mainly on geranyl acetate (1.49%) and borneol (0.97%) in addition to linalool (72.35%). Additionally, accumulation of monoterpene alcohols was observed during maturation process of coriander fruit.

PRACTICAL APPLICATIONS

The chemical composition of the essential oil of coriander ( Coriandrum sativum L.) fruits is characterized by the occurrence of numerous components with great economical values. The oxygenated monoterpene and linalool were the most used ingredient in the cosmetic, perfume and food industries. On the other hand, the increasing market demands of the oxygenated components, widely present in this oil make it in the first rank of natural product. The formers were only obtained from the mature fruits. In this context, knowledge of their evolution during maturation process of the fruits seems to be a helpful tool for a better use of this economical potential.     

BIOCHEMICAL CHARACTERIZATION OF BORAGE (BORAGO OFFICINALIS L.) SEEDS

Gas chromatography–mass spectrometry analysis of seed Borago officinalis essential oil (EO) revealed the presence of 16 volatile components. β-Caryophyllene (26%) and p-cymene-8-ol (19.7%) represented the major components, while nonadecane (0.7%) and hexanol (0.7%) were the minor ones. The EO composition was characterized by higher abundance of oxygenated monoterpenes (27.7%), followed by sesquiterpenes (26%). Fatty acid composition showed the predominance of linoleic (35.4%), oleic (24.2%) and γ-linolenic (20.4%) acids. Polyphenols were analyzed by reversed-phase high-performance liquid chromatography after acid hydrolysis of phenolic acid esters. Six phenolic acids were identified in seed extract and rosmarinic acid was the predominant one with 1.65 mg/g dry matter weight equivalent to 33% of total phenolic acids.

PRACTICAL APPLICATIONS

Borage ( Borago officinalis L.) is of great interest because of its medicinal and nutritional properties. In fact, thanks to its characteristic composition in fatty acids, particularly high levels of gamma-linolenic acid in its seed oil, borage has gained importance. The potent consumers of this medicinal plant are hypertensive and hypercholesterolemic people. Borage consumption is also recommended for people suffering from rheumatism and eczema.
Unfortunately, the knowledge about antioxidative/antiradical properties of borage is very scanty. So, recently, an extensive investigation was focused on the antioxidant properties of borage extracts. These extracts showed excellent antioxidant properties and their effects were attributed to their phenolic constituents. These antioxidants can be concentrated, either as crude extracts or individual phenolic compounds, to be used in highly unsaturated oils such as marine oils. Furthermore, borage consumption has been reported as a possible gastric cancer protective factor.