Zehra Güler

The essential mineral concentration of torba yoghurts and their wheys compared with yoghurt made with cows', ewes' and goats' milks.

Comparative studies on yoghurts made from cows’, ewes’ and goats’ milks with respect to mineral concentrations are limited and warrant further investigation. The objective of this study was to analyse the gross chemical composition as well as the concentration of essential minerals in concentrated (torba) yoghurts made from cows’, ewes’ and goats’ milk compared with those in regular yoghurts and wheys. The elements were determined by simultaneous inductively coupled plasma optical emission spectrometry. Ewe torba yoghurt was significantly higher in calcium, sodium, phosphorus, magnesium, selenium, zinc, cobalt, copper and iron concentrations compared with goat and cow torba yoghurts. It is recommended that torba yoghurts made from different types of milk may be considered an important source of phosphorus, calcium, magnesium, selenium and zinc over the regular yoghurts and wheys. Whey samples are also an excellent source of lactose as well as sodium and potassium.

Volatile compounds in the peel and flesh of cucumber (Cucumis sativus L.) grafted onto bottle gourd (Lagenaria siceraria) rootstocks

Summary The objective of this study was to investigate the distribution of volatile organic compounds (VOCs) in the peel and flesh of the cucumber (Cucumis sativus L.) cultivar ‘Çengelköy’ grafted onto different bottle gourd rootstocks, as VOCs play an essential role in fruit quality. Three genotypes of bottle gourd (Lagenaria siceraria; ‘33-35’, ‘33-41’ and ‘46-03’) were chosen as being representative of Turkish bottle gourd germplasm. The VOCs in each rootstock-scion combination were analysed using carboxen-divinylbenzene-polydimethylsiloxane fibres for solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The VOCs (Z)-6-nonenol (21.4 – 28.6%), (E,Z)-2,6-nonadienol (3.2 – 13.0%), (E,Z)-3,6-nonadienol (1.9 – 7.1%), 1-nonanol (4.9 – 7.2%), (E)-2-nonenal (3.9 – 6.6%), (E,Z)-2,4-heptadienal (5.7 – 6.9%), (Z)-6-nonenal (3.6 – 5.4%), (E)-2-hexenal (0.9 – 4.4%), (E,E)-3,5-octadien-2-one (3.2 – 3.5%), and hexanal (1.9 – 3.6%) were the most abundant compounds found in cucumber peel. Grafting had a significant (P ≤ 0.05) effect on the percentage composition of the major VOCs in peel. (E,Z)-2,6-Nonadienal (34.3 – 41.5%), (E)-2-nonenal (15.5 – 19.9%), (Z)-6-nonenal (5.9 - 8.0%), (Z,Z)-3,6-nonadienol (2.6 – 8.4%), (Z)-6-nonenol (2.7 – 7.9%), 3-decyne (2.1 – 3.4%), and (E,Z)-2,6-nonadienol (1.9 – 5.7%) were the most significant volatiles in cucumber flesh. Of these compounds, (E,Z)-2,4-heptadienal, (E,E)-3,5-octadien-2-one, and 3-decyne were identified as cucumber VOCs for the first time. The results showed that the percentage composition of VOCs in the peel and flesh of cucumbers grafted onto bottle gourd ‘33-41’ were closest to those in ungrafted control cucumber, ‘Çengelköy’. Therefore, Turkish bottle gourd genotype ‘33-41’ has high potential as a rootstock for cucumer grafting.

Changes in Gross Chemical Compositions of Ewe and Goat Colostrum During Ten Days Postpartum

Abstract Keskin, M., Güler, Z., Gül, S. and Biçer, O. 2007. Changes in gross chemical compositions of ewe and goat colostrum during ten days postpartum. J. Appl. Anim. Res., 32: 25–28. This study was carried out to determine the exact ‘Colostrum producing period’ in Awassi ewes and Shami (Damascus) goats in Hatay province of Turkiye based on changes in gross composition of milk during 10 days post partum. Goats produced high crude protein and fat milk for 3–5 days post partum. Whereas, in ewes it was 3 days. Ewes colostrum was richer in respect to total solids (TS), crude protein (CP), fat, lactose and ash as compared to goats colostrum. It is recommended that first three days milk (colostrum) must be fed to kids/lambs for maximum benefits.

Volatile Compounds and Sensory Properties in Various Melons, Which were Chosen from Different Species and Different Locations, Grown in Turkey

Gas chromatography coupled to mass spectrometry using a static head space technique was applied to analyze the volatile aromatic compounds of various melons collected from different locations in Turkey. Some physicochemical and sensory analyses were also made. A total of 33 volatile compounds were identified. Differences in the physicochemical and sensory properties of various Turkish melon samples were observed. The multivariate analyses by the volatile compounds separated the three varieties into groups successfully. The most abundant volatile compounds as mean value in all melon varieties were ethyl acetate (22.10%), acetaldehyde (13.65%), and ethanol (23.25%). The results showed that Cantaloupe melons were more preferred by panelists, which had relatively high levels of esters being responsible for strong fruit flavor, like melon, as well as high total soluble solid content and low titratable acidity compared with Inodorus and Simama.

Profiles of Organic Acid and Volatile Compounds in Acid-Type Cheeses Containing Herbs and Spices (Surk Cheese)

A study was conducted to evaluate the basic chemical composition, organic acids, volatile compound profiles, and overall acceptability of Surk cheese (acid cheese). The organic acids were determined by reverse phase high performance liqued chromatography method, and volatile compounds were analyzed by static headspace/gas chromatography/mass spectrometry technique. A total of 134 volatile compounds, including 42 esters, 40 terpenes, 15 alcohos, 11 free fatty acids, 6 ketones, 5 aldehydes, 4 alkenes, 4 phenyl propanoids, 3 phenolics, and 4 other compounds, were identified in the Surk cheeses. The main compounds were found to be carvacrol, γ-terpinene, p-cymene, hexanoic acid, octanoic acid, decanoic acid, butanoic acid, and eugenol. The mean total organic acid content of the Surk cheese was 1.71 g/100 g. The main organic acid in the Surk cheese was lactic acid (1067 mg/100 g), followed by acetic, propionic, oxalic, formic, citric, pyruvic, orotic, hippuric, and uric acids.

Volatile organic compounds in the aril juices and seeds from selected five pomegranate (Punica granatum L.) cultivars

ABSTRACT A study was conducted to investigate the distribution of volatile organic compounds in the juice and seed of the most popular five pomegranate cultivars (“Ekşi,” “Devedişi,” “Hicaz,” “Katırbaşı,” and “Keben”) in Turkey. The volatile organic compounds were analyzed using solid phase micro-extraction and gas chromatography–mass spectrometry. A total of 60 volatile organic compounds, belonging to six chemical groups including aldehydes, alcohols, esters, terpenes, ketones, acids, and phenol were identified. There were 11 volatile organic compounds (1-hexanol, [Z]-3-hexen-1-ol, 1-octanol, α-terpineol, β-myrcene, limonene, [E]-α-bergamotene, β-caryophyllene, hexanal, [E]-2-hexenal, and guaiacol) common to all five pomegranate juices and seeds. Hexalin, phenylacetaldehyde, 3-methyl butanal, and methyl-(1-methylethenyl) benzene were found in seeds only. According to discriminant analysis based on Eigenvalues, volatile organic compounds recovered in the juices could be used to discriminate and classify the pomegranate cultivars. “Devedişi” and “Hicaz” were the most promising cultivars with respect to the largest volatile organic compounds, high total soluble solid and deep red color.

Volatile organic compounds in watermelon (Citrullus lanatus) grafted onto 21 local and two commercial bottle gourd (Lagenaria siceraria) rootstocks

Summary Volatile organic compounds (VOCs) are responsible for flavour development in watermelon (Citrullus lanatus). The objective of this study was to investigate the rootstock effects of 21 local bottle gourd [Lagenaria siceraria (Molina) Standl.] accessions collected from the Mediterranean region (Turkey) on the concentrations of VOCs in watermelon over 2 years. The watermelon cultivar ‘Crimson Tide’ was used as the scion and two commercial bottle gourd rootstocks were also used for comparison. The VOCs in each rootstock-scion combination were analysed using static headspace (SHS) and gas chromatography-mass spectrometry (GC-MS). A total of 24 VOCs were identified in watermelon fruit, including 11 aldehydes, seven alcohols, four ketones, one heterocyclic compound, and one acid. Acetaldehyde (25.9 – 39.5% of the total peak areas), propanal (5.0 – 8.3%), 2-propanone (2.5 – 4.9%), pentanal (2.1 – 3.6%), hexenal (14.5 – 22.6%), (E)-2-hexenal (0.4 – 2.3%), 6-methyl-5-hepten-2-one (10.0 – 19.05%), nonanal (1.6 – 4.4%), (Z)-6-nonenal (4.0 – 9.8%), (E)-2-nonenal (0.6 – 2.0%), (E,Z)-2,6-nonadienal (2.1 – 3.7%), (Z)-6-nonenol (1.0 – 3.2%), and (E,Z)-3,6-nonadienol (1.0 – 3.7%) were the most abundant VOCs found in all watermelon scions. There was no significant effect (P ≥ 0.05) of rootstock on the concentrations of acetaldehyde, propanal, pentanal, heptanal, ethanol, 1-pentanol, 2-propanone, 2-pentyl furan, or acetic acid. Propanal, 2-propanone, and acetic acid were identified as VOCs in watermelon for the first time. Hexanal, (Z)-6-nonanal, and 6-methyl-5-hepten-2-one concentrations were strongly affected by rootstock. The results showed that the local bottle gourd accessions 07-06 and 31-09, in particular, were the most promising genotypes in terms of producing favourable VOCs. Except for the local bottle gourd accessions 33-35, 01-17, and 07-04, the other 18 gourds accessions had high potential as rootstocks for breeding programmes in watermelon with regard to desirable VOC concentrations. Rootstock 31-09 should be considered for commercial production in terms of improved disease resistance, fruit yield, and fruit quality.

Characterization of volatile compounds and organic acids in ultra-high-temperature milk packaged in tetra brik cartons

ABSTRACT A study was conducted to evaluate the basic chemical composition, organic acids and volatile compound profiles of ultra-high-temperature milk samples sold in Turkey. The organic acids were determined by reverse-phase high-performance liquid chromatography method, and volatile compounds were analyzed by headspace solid phase micro-extraction/gas chromatography/mass spectrometry technique. A total of 43 volatile compounds including 4 aldehydes, 5 alcohols, 10 ketones, 9 acids, 9 aromatic hydrocarbons, 3 nitrogenous, 2 sulfur containing compounds, and 1 alkane hydrocarbon, were identified in the ultra-high-temperature milk samples. The main compounds were found to be oxime methoxy phenyl, 2-heptanone, 2-mercapto-4-phenylthiazole, 2-amino-5-ethoxycarbonyl benzophenone, acetic acid, 2,6,10,14-tetramethyl pentadecane, and 2-nonanone. The main organic acid in the ultra-high-temperature milk was citric acid a mean value of 133 mg/100 mL, followed by formic, lactic, succinic, oxalic, acetic, orotic, propionic, pyruvic, hippuric, and uric acids.

Identification of volatile organic compounds (VOCs) in different colour carrot (Daucus carota L.) cultivars using static headspace/gas chromatography/mass spectrometry

Abstract Volatile organic compounds (VOCs) as well as sugar and acid contents affect carrot flavour. This study compared VOCs in 11 carrot cultivars. Gas chromatography/mass spectrometry using static headspace technique was applied to analyse the VOCs. The number of VOCs per sample ranged from 17 to 31. The primarily VOCs identified in raw carrots with the exception of “Yellow Stone” were terpenes, ranging from 65 to 95%. The monoterpenes with values ranging from 31 to 89% were higher than those (from 2 to 15%) of sesquiterpenes. Monoterpene α-terpinolene (with ranging from 23 to 63%) and (-)-α-pinene (26%), and alcohol ethanol (35%) was the main VOC in extracts from the nine carrot cultivars, “Purple” and “Yellow Stone”, respectively. As a result, among 16 identified monoterpenes, 7 monoterpenes (-)-α-pinene, (-)-β-pinene, β-myrcene, d-limonene, γ-terpinene, α-terpinolene and p-cymene constituted more than 60% of total VOCs identified in carrots including “Atomic Red”, “Nantes”, “Cosmic Purple”, “Red Samurai”, “Eregli Black”, “White Satin”, “Parmex” and “Baby Carrot”. Thus, these cultivars may advise to carrot breeders due to the beneficial effects of terpenes, especially monoterpenes on health.