Adulteration of Essential Oils: A Multitask Issue for Quality Control. Three Case Studies: Lavandula angustifolia Mill., Citrus limon (L.) Osbeck and Melaleuca alternifolia (Maiden & Betche) Cheel

The quality control of essential oils (EO) principally aims at revealing the presence of adulterations and at quantifying compounds that are limited by law by evaluating EO chemical compositions, usually in terms of the normalised relative abundance of selected markers, for comparison to reference values reported in pharmacopoeias and/or international norms. Common adulterations of EO consist of the addition of cheaper EO or synthetic materials. This adulteration can be detected by calculating the percent normalised areas of selected markers or the enantiomeric composition of chiral components. The dilution of the EO with vegetable oils is another type of adulteration. This adulteration is quite devious, as it modifies neither the qualitative composition of the resulting EO nor the marker’s normalised percentage abundance, which is no longer diagnostic, and an absolute quantitative analysis is required. This study aims at verifying the application of the two above approaches (i.e., normalised relative abundance and absolute quantitation) to detect EO adulterations, with examples involving selected commercial EO (lavender, bergamot and tea tree) adulterated with synthetic components, EO of different origin and lower economical values and heavy vegetable oils. The results show that absolute quantitation is necessary to highlight adulteration with heavy vegetable oils, providing that a reference quantitative profile is available.

Volatile Compounds, Odour and Flavour Attributes of Lamb Meat from the Navarra Breed as Affected by Ageing

This study aimed to assess the influence of ageing on the volatile compounds, as well as odour and flavour attributes of lamb meat from the Navarra breed. Twenty-one male lambs were fed a commercial concentrate diet after weaning and were harvested at 101 ± 6.5 days of age. From the Longissimus thoracis, 26 volatile compounds were identified, with hexanal, 2-propanone, and nonanal the most abundant (57.17% relative percentage abundance, RPA). The effect of ageing (1 vs. 4 d) was observed (p < 0.05) in six compounds: 1,4-dimethylbenzene decreased with ageing, while tridecane, 3-methylbutanal, 2-heptanone, 3-octanone, and 1-octen-3-ol increased. In general, ageing was linked to a decrease in livery and bloody flavour, bloody odour and ethanal, and an increase in pentane, hexanal, and heptanal, which are usually associated with fresh green grass and fat descriptors. Consequently, ageing lamb from the Navarra breed for four days might have a positive effect on meat sensory odour and flavour quality.

An assessment of composition and diversity of fin fish in the upper course of Otamiri river, Imo State, South-Eastern Nigeria

The composition and diversity of the fin fish of upper course of Otamiri River was study for the period of three months to evaluate the likely effects of the recent anthropogenic activities around the river on the fish species. Water sample for physcio-chemical parameter were collected and analyses using conventional field and standard laboratory techniques. Likewise, the fish samples were collected bi-weekly using active and passive fishing gear. All the physic-chemical parameters measured fall within the standard recommended limit for aquatic management except the pH, ammonia, total suspended solid, Nitrate and carbon (iv) oxides. Also, sixteen species of fish belong to 9 fish families were recorded with the families, Cichlidae recording the highest percentage abundance and also found to be most diverse. The anthropogenic activities around the river couple with over-exploitation of the fisheries resources were found accounted for the decline in the fishes composition and diversity of the river.

Phytoplankton Diversity and Abundance in Lake Ribadu, Adamawa State, Nigeria

This study was carried out to look at the phytoplankton diversity and abundance in Lake Ribadu, Fufore Local Government Area, Adamawa State, Nigeria. The study was carried out for a period of 6 months (July to December 2016). Phytoplanktons sampling was carried out by using the plankton net of mesh size 55µm by hauling horizontally for five meters. Frequency counts, percentages were used to analyzing the phytoplankton species composition and abundance while ComEcolPaC (a Microsoft Excel 2003 based program) was used to analyze the variation in the diversity indices. A total of Twenty one (21) species were observed in the study sites. Bacillariophyceae recorded the highest with the percentage abundance of 37.8% followed by Chlorophyceae with 35.12%, Myxophyceae with 25.82% while Chrysophyceae with 1.53% is the least abundant. The study recommends that Monitoring of the lake by the immediate community and regulation of all anthropogenic activities should be given topmost priority as part of the environmental management policy for the sustainability of aquatic resources of the lake.

Chemical constituents, antimicrobial and antioxidant properties of the aerial parts of Coccinia barteri

Phytochemical analysis of n-hexane, ethyl acetate and methanol extracts of the aerial parts of Coccinia barteri was carried out. These extracts exhibited satisfactory inhibitory activities against bacteria and fungi strains, which include; Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, Salmonella typhii, Klebsiella pneumoniae, Candida albicans, Aspergillus niger, Penicillium notatum and Rhizopus stolonifer. Methanol extract of C. barteri possesses antioxidant activity by scavenging DPPH free radical with IC50 of 187.56 μg/mL, using DPPH antioxidant assay. GC-MS analysis of n-hexane, ethyl acetate and methanol extracts of the plant principally revealed the presence of phytol, ethyl hexadecanoate and clionasterol with their corresponding percentage abundance of 57.75%, 18.33% and 9.79%, respectively.

Assessment of fishing gear and catch rate in Oguta Lake, south Eastern Nigeria

This study was carried out in Oguta Lake, Imo State, Nigeria, from January, 2012 to December, 2013 at five stations (Onu Utu, Okposha, Ogbe Hausa, Osemotor and Ede Ngwugwu) to ascertain the percentage abundance and catch rate of gear and craft. The average weight of fish caught per canoe per day ranged between 3.2 kg for Basket and Drum traps to 47.1 kg for boat seine net. The gill nets ranged between 6.0 to 13.0kg per canoe per day with mean weight of 8.60±2.91kg, the cast net had values ranging from 1.0 to 7.0 kg with a mean weight of 4.3±2.49 kg. Lift net yielded an average of 3.4 kg per canoe per day. Gill nets were the main gear used by fishers, followed by long lines and cast nets at the lake. It is important to locate all the fishers operating in the lake and daily record of catches be collected for a more accurate picture of the total catch and fish species. Mesh size regulation prevent over exploitation of young fish, before they attain sexual maturity. It is recommended that the cost of procuring fishing inputs such as fishing gear and crafts and safety kits should be monitored by government and be subsidized for the fishers.Key words: drum trap, crafts, catch, exploitation, Oguta, mesh size, trap

The melliferous potential of apiflora of southwestern Vojvodina (Serbia)

The individual and community-level melliferous potential of apiflora was evaluated in southwestern Vojvodina in order to assess its significance and contribution to the bee pasture. Seven plant communities belonging to ruderal, segetal and floodplain type of vegetation, with a total of 279 plant species were registered. Apifloristic and phytocoenological investigations included the determination and analysis of honey plants using the following parameters: total number, percentage, abundance and frequency of these species in the communities, as well as their intensity of pollen and nectar production. The coenotic coefficient of melliferousness (CCm) indicating the melliferous potential of each community, was calculated based on the above parameters. Although the greatest number of melliferous species was found in the ass. Chenopodio-Ambrosietum artemisiifoliae (132), the highest percentage (80%) of them was registered in the ass. Consolido-Polygonetum avicularis. Considering the coefficients of nectar and pollen production, the most valuable honey plants commonly present in the majority of communities were: Cirsium arvense, Rubus caesius, Lythrum salicaria, Daucus carota, Trifolium pratense, Dipsacus laciniatus, Medicago sativa, Asclepias syriaca, Cichorium intybus and Taraxacum officinale. The low abundance and frequency of melliferous species within the Consolido-Polygonetum avicularis, Polygonetum convolvulo-avicularis and Populetum nigrae-albae communities indicated their poor contribution to the bee pasture. Within ruderal vegetation, the highest CCm was registered in Amorpho-Typhaetum, providing, theoretically, the richest food resource for the honeybees in the investigated area.

Growth of off-flavours-caused phytoplankton in milkfish culture fertilized with different N:P

<p class="NoParagraphStyle" align="center"><strong>ABSTRACT</strong><strong></strong></p><p class="NoParagraphStyle" align="center"><strong> </strong></p><p class="NoParagraphStyle">Milkfish culture in ponds currently use inorganic fertilizers for growing phytoplankton. Giving of urea and SP (<em>superphosphate</em>) too much in the pond environment will cause eutrophication and often cause fish smell of mud (off-flavours). Off-flavours in fish is caused by two chemical compounds those are geosmin and 2-methylisoborneol (MIB). Research was performed to evaluate the growth of off-flavours-caused phytoplankton in milkfish culture fertilized by different N:P. This study used nine ponds. Ponds are used for fish rearing area of 600 m². Fish reared in ponds at the density of 1 fish/m² for 90 days. The study were showed that types of phytoplankton obtained were the phylum Chlorophyta, Cyanophyta, Bacillariophyta, Dinoflagellate, Glaocophyta, and Euglenophyta. Percentage abundance of phytoplankton that produced geosmin and MIB (Cyanophyta) in each treatment was less than 50% of the percentage of total phytoplankton. Organoleptic scores showed that the treatment pond G (N:P ratio 4) score of 7 (not fresh, no off-flavours). Organoleptic scores of treatments with N:P ratio 5, 15 and 30 in pond A (freshwater pond) and pond B (brackish water pond) were 8 (fresh, no off-flavours).</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords:<em> </em>extensive pond-culture, phytoplankton, N:P ratio, organoleptic</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle" align="center"><strong>ABSTRAK</strong></p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Budidaya bandeng di tambak saat ini menggunakan pupuk anorganik untuk menumbuhkan fitoplankton. Pemberian pupuk urea dan SP (<em>superphosphate</em>) yang berlebihan pada lingkungan budidaya akan menyebabkan kondisi perairan tersebut menjadi sangat subur dan sering menyebabkan ikan bau lumpur <em>off-flavours</em>. Bau lumpur di ikan disebabkan oleh dua senyawa kimia yaitu geosmin dan 2-methylisoborneol (MIB). Penelitian dilakukan untuk menguji pertumbuhan fitoplankton penyebab bau lumpur pada tambak ikan bandeng dipupuk dengan N:P berbeda. Penelitian ini menggunakan sembilan petak tambak. Tambak yang digunakan berukuran 600 m². Ikan ditebar di tambak dengan kepadatan 1 ikan/m² dan dipelihara selama 90 hari. Hasil penelitian menunjukkan fitoplankton yang didapatkan antara lain berasal dari filum Chlorophyta, Cyanophyta, Bacillariophyta, Dinoflagellata, Glaocophyta, dan Euglenophyta. Kelimpahan fitoplankton Cyanophyta lebih kecil dibandingkan dengan fitoplankton bukan Cyanophyta yaitu di bawah 50%. Skor organoleptik perlakuan tambak G (rasio N:P 4) yaitu 7 (kurang segar, tidak bau lumpur). Skor organoleptik perlakuan rasio N:P 5, 15, dan 30 di tambak A (tambak air tawar) dan tambak B (tambak air payau) adalah 8 (segar, tidak bau lumpur).</p><p class="NoParagraphStyle"> </p><p>Kata kunci: budidaya kolam ekstensif, fitoplankton, rasio N:P, organoleptik</p>

A chironomid-based reconstruction of summer temperatures in NW Iceland since AD 1650

Few studies currently exist that aim to validate a proxy chironomid-temperature reconstruction with instrumental temperature measurements. We used a reconstruction from a chironomid percentage abundance data set to produce quantitative summer temperature estimates since AD 1650 for NW Iceland through a transfer function approach, and validated the record against instrumental temperature measurements from Stykkishólmur in western Iceland. The core was dated through Pb-210, Cs-137 and tephra analyses (Hekla 1693) which produced a well-constrained dating model across the whole study period. Little catchment disturbance, as shown through geochemical (Itrax) and loss-on-ignition data, throughout the period further reinforce the premise that the chironomids were responding to temperature and not other catchment or within-lake variables. Particularly cold phases were identified between AD 1683–1710, AD 1765–1780 and AD 1890–1917, with relative drops in summer temperatures in the order of 1.5–2°C. The timing of these cold phases agree well with other evidence of cooler temperatures, notably increased extent of Little Ice Age (LIA) glaciers. Our evidence suggests that the magnitude of summer temperature cooling (1.5–2°C) was enough to force LIA Icelandic glaciers into their maximum Holocene extent, which is in accordance with previous modelling experiments for an Icelandic ice cap (Langjökull).