Bahar Gümüş

Prediction of the Weight of Aquacultured Rainbow Trout (Oncorhynchus mykiss) by Image Analysis

Prediction relationships between weight and image features were established with a high correlation for whole aquacultured rainbow trout. Three hundred fish from three different farms were used. The fish were temporarily removed from the raceway, anesthetized, and their picture was taken by a digital camera. A reference square of known surface area and color was placed beside the fish. The fish were then returned to the raceway alive. The image was analyzed, and the view area of the fish was calculated using the area of the reference square. The average color of the fish was also determined (L*, a*, and b* values). The following equations were used to fit the view area (X) vs. weight (Y) data: linear, power, and second order polynomial. The R2 values for the used equations were: linear = 0.98; power = 0.99; polynomial = 0.98. Image analysis can be used reliably to predict the weight of whole aquacultured rainbow trout. In addition, color and other visual attributes can be objectively determined by image analysis to sort by visual quality.

Effects of olive oil and olive oil-pomegranate juice sauces on chemical, oxidative and sensorial quality of marinated anchovy.

This study describes the potential use of olive oil and olive oil-pomegranate juice sauces as antioxidant, preservative and flavoring agent in fish marinades. The olive oil and sauces, produced from emulsifying of olive oil and pomegranate juice with gums, were blended with marinated anchovy (Engraulis encrasicholus) fillets. The aim of the present study was to produce a new polyphenol-rich marinade sauces by emulsifying pomegranate juice with olive oil in different proportions (25%, 35% and 50%v:v). In order to evaluate the effects of olive oil and olive oil-pomegranate juice sauces on quality of anchovy marinades, the chemical (TVB-N and TMA), oxidative (peroxides value, K230, thiobarbituric acid and K270) and sensory analyses were carried out during storage at 4°C. The present study showed that saucing of anchovy marinades with olive oil-pomegranate sauce can retard the undesirable quality changes, prolong the lipid oxidation and improve the sensory properties.

Quality Evaluation of Alaska Pollock (Theragra chalcogramma) Roe by Image Analysis. Part I: Weight Prediction

Roe is an important product of the Alaska pollock (Theragra chalcogramma) industry. About 31% of the value for all pollock products comes from roe, yet roe is 5% of the weight of the fish. Currently, the size (weight), color, and maturity of the roe are subjectively evaluated. The objective of this study was to develop methods to predict the weight of Alaska pollock roe based on its view area from a camera and to differentiate between single and double roes. One hundred and forty-two pollock roes were picked from a processing line in a Kodiak, AK plant. Each roe was weighed, placed in a light box equipped with a digital video camera, images were taken at two different angles from one side, then turned over and presented at two different angles again (four images for each roe). A reference square of known surface area was placed by the roe. The following equations were used to fit the view area (X) versus weight (Y) data: linear, power, and second-order polynomial. Error rates for the classification of roes by weight decreased significantly when weight prediction equations for single and double roes were developed separately. A “turn angle” method, a “box” method, and a “modified box” method were tested to differentiate single and double roes by image analysis. Machine vision can accurately determine the weight of pollock roe. Practical Application Abstract: An image analysis method to accurately determine if pollock roe is a single or a double was developed. Then view area versus weight correlations were found for single and double roes that reduced incorrect weight classification rates to half that of human graders.

Determination of Volume of Alaska Pollock (Theragra chalcogramma) by Image Analysis

The objective of this study was to develop two methods to predict the volume of whole Alaska pollock and to compare the results with the experimentally measured volumes. One hundred fifty-five whole pollock, obtained from a Kodiak processor, were individually immersed in a graduated cylinder equipped with an outflow tube to catch the displaced water as a result of immersion. The weight of the water was recorded. Then the fish were placed in a light box equipped with a digital video camera, and the side view and top view recorded (2 images for each fish). A reference square of known surface area was placed by the fish. A cubic spline method to predict volume by integration of cross-sectional area slices based on the top and side views and an empirical equation using dimensional (length L, width W, depth D) measurements at three locations of the fish image were developed. The R2 value for the correlation between the L × W × D versus measured volume was 0.987. The best R2 for the correlation of the predicted volume by the cubic spline method versus the measured volume was 0.99. Image analysis can be used reliably to predict the volume of whole Alaska pollock.

Quality Evaluation of Alaska Pollock (Theragra chalcogramma) Roe by Image Analysis. Part II: Color Defects and Length Evaluation

In the second part of the study of the quality evaluation of pollock roe by image analysis, methods to quantify the color defects (green spots, dark strips, dark color, and uneven coloring due to “freezer burn”) were developed. Dark roes can be detected by their average L* value. Dark strips can be detected by quantifying the percentage of pixels that have an L* value below an L*threshold. Since there is wide variation among the average colors of the roes, this L*threshold value must be auto-adjusting to the color of the individual roe. Green spots can be detected by their darker color and by ignoring red blood vessels by setting an upper a*threshold. In this study, identifying pixels with L* values less than the L*threshold = 66% of the L*average of the roe, and a* values less than an a*threshold = 20 successfully detected dark strips and green spots. Detection and quantification of uneven color and “freezer burn” required a “smoothing” of the roe colors to reduce details. The “color primitives” method was used, with a setting of a color threshold (CT) = 75. The resulting images were analyzed by setting L*threshold values of 60, 65, 70, 75, 80, and 85% of L*average of individual roes. More surface area of the roe was judged as defective with increasing L*threshold. With proper selection of L*threshold, a*threshold, and CT value, image analysis can accurately quantify the color defects of pollock roe. Practical Application Abstract: Automation of pollock roe sorting by color would streamline the operation, reduce error rates, and help with standardization of quality. Combined with other capabilities of machine vision such as sorting by weight, this technology can be used for multiple purposes simultaneously.

Optimization of Antioxidant Activity and Phenolic Compound Extraction Conditions from Red Seaweed (Laurencia obtuse)

ABSTRACT Response surface methodology was used to investigate the effect of ultrasound-assisted extraction conditions including solvent:seaweed ratio (10:1–30:1), extraction temperature (30–50°C), and extraction time (30–60 min) on the total phenolic compounds and antioxidant activity of red seaweed (Laurencia obtuse) extracts. The optimum extraction parameters for maximum phenolic content were as follows: solvent:seaweed ratio, 30:1; extraction temperature, 50°C; and extraction time, 42.8 min. The experiment results showed that the solvent:seaweed ratio was the most significant parameter for the extraction. The optimum extraction conditions for maximum antioxidant activity were as follows: solvent:seaweed ratio, 24.3:1; extraction temperature, 45.3°C; and extraction time, 58 min. Under the above-mentioned conditions, the experimental total phenolic content and antioxidant activity value were 26.23 ± 0.75 mg GAE/g seaweed and 120.89 ± 0.81 TEAC, respectively, of seaweed tested, which are well compatible with the predicted contents.

A review on antimicrobial properties of marine macroalgae extracts

Bu derlemede, denizel makroalg ozutlerinin antimikrobiyal ozellikleri uzerine yapilan calismalar arastirilmistir. Bircok arastirmaci, makroalg ozutlerinin antimikrobiyal aktivitesini belirlemek icin calismalar yapmistir. Cesitli literaturlerde, yesil, kahverengi ve kirmizi makroalg ozutlerinin, maya, kuf ve bakterilere karsi antimikrobiyal aktiviteye sahip oldugu bildirilmektedir. Denizel makroalg ozutlerinin antimikrobiyal etkisinin iceriginde bulunan kimyasal bilesenlerden (aminoasitler, yag asitleri, terpenoidler, florotanninler, fenolik bilesenler, steroidler, halojenli ketonlar ve alkanlar gibi) kaynaklandigi rapor edilmektedir. Bu derlemenin amaci, denizel makroalg ozutlerinin antimikrobiyal ozelliklerini arastirmak ve mikroorganizmalara karsi antimikrobiyal aktivitelerini gostermektir.

Antioxidant Activities of Citrus Albedo and Flavedo Fragments Against Fish Lipid Oxidation

ABSTRACT This research aimed to inhibit the oxidation of fish lipid by adding the ethanol extracts of albedo and flavedo fragments of grapefruit, sour orange, and bergamot. The samples were stored at 25°C, and analyses were performed on weekly intervals. The albedo fragments of sour orange extract had the highest antioxidant activity (0.342 ± 0.002 µM Trolox) and total phenolic content (5.29 ± 0.00 g GAE/100 g dry matter). Lipid oxidation increased rapidly in control samples compared to the extract treatments. The lowest scores for thiobarbituric acid reactive substances (TBARS), para-anisidine value, peroxide value, and UV absorbance values were determined in sour orange albedo extracts as 5.21 mg MDA/kg, 17.81 and 4.78 meq O2/kg, 2.24, and 0.403, respectively, at the end of the storage. More successful results were obtained with the peels of grapefruit and bergamot in supressing the lipid oxidation. Bergamot extract was the most preferred citrus in terms of sensory analyses.

Tüketilebilir iki makroalg ekstraktının antimikrobiyal aktivitelerinin belirlenmesi

Bu calismada, Ulva rigida ve Gracilaria verrucosa makroalglerinden elde edilen etanol ozutlerinin antimikrobiyal aktivitesi incelenmistir. U. rigida ve G. verrucosa makroalgleri Inciralti (Izmir, Turkiye)sahilinden toplanmistir.Laboratuarda ornekler ilk once musluk suyu ile daha sonra saf su ile yikanarak temizlenmis ve 40 °C’de 24 saat sure ile kurutulmustur. Kurutulan ve toz haline getirilen ornekler (10 g) amber renkli erlene tartilmis ve uzerine 200 ml %95’lik etanol eklenmistir. Bu karisimlar calkalamali su banyosunda, farkli ekstraksiyon sicakliklarinda (30 °C, 45 °C ve 60 °C) 30 dakika sure ile ekstrakte edilmistir. Bu ozutler filtre edildikten sonra doner buharlastirici kullanilarak cozgen uzaklastirilmistir. Farkli sicakliklarda U. rigida ve G. verrucosa makroalglerinden saglanan etanol ozutlerinin kagit disk difuzyon agar metodu kullanilarak 6 bakteri ( Bacillus subtilis , Staphylococcus aureus , Enterococcus faecalis , Listeria monocytogenes , Escherichia coli ve Pseudomonas aeruginosa ) ve 2 mantar ( Aspergillus brasiliensis ve Candida albicans ) icin antibakteriyel ve antifungal aktiviteleri in-vitro olarak degerlendirilmistir. Test edilen tum ozutlerin A. brasiliensis haric tum bakteri ve mantarlara karsi antimikrobiyal etkiye sahip oldugu tespit edilmistir.In this study, antimicrobial activity of the possibility of using ethanol extracts obtained from seaweeds Ulva rigida and Gracilaria verrucosa were examined. U. rigida and G. verrucosa were collected from the Coast of Inciraltı (Izmir, Turkey). In the laboratory, the samples were cleaned by rinsing with tap and distilled water, and then dried at 40 °C for 24 hours. Dried and pulverized seaweed samples (10 g) were weighed into an amber Erlenmeyer flask, and 200 ml of 95% (v/v) ethanol was added. The mixture was shaken and extracted in a water bath shaker at temperatures of 30 °C, 45 °C and 60 °C for 30 min. The extracts were filtered, and ethanol was removed using a rotary evaporator to obtain extracts. Ethanolic extracts of U. rigida and G. verrucosa obtained at different temperatures were evaluated in vitro for antibacterial and antifungal activity on six bacteria (Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Listeria monocytogenes, Escherichia coli and Pseudomonas aeruginosa) and two fungi (Aspergillus brasiliensis and Candida albicans) using the paper disk agar diffusion method. All extract groups tested were found to have antimicrobial activity against all bacteria and fungi, except for Aspergillus brasiliensis.