Metin Guldas - Academia.edu (original) (raw)

Papers by Metin Guldas

Communications in computer and information science, 2023

Akademik Gıda, Aug 1, 2005

Greyfurt segment konservesi hem dogrudan tuketilebilmekte hem de pasta ve benzeri urunlerde kulla... more Greyfurt segment konservesi hem dogrudan tuketilebilmekte hem de pasta ve benzeri urunlerde kullanilmaktadir. Asitligi yuksek greyfurt konservesi gibi urunlerde bazi maya ve kufler ureyebilmekte, bazi bakterilerin sporlari canli kalabilmektedir. Greyfurt dilim segment zarlarinin kimyasal yolla soyulmasi icin kullanilan kimyasallar sure, sicaklik ve konsantrasyona bagli olarak meyve dokusuna kismen gecebilmektedir. HACCP Kritik Kontrol Noktalarinda Tehlike Analizi ' in greyfurt dilim konservesi uretiminde kullanilmasi, mevcut risklerin elemine edilmesi ve tehlikelerin ortadan kaldirilarak daha guvenli bir urun uretilmesini saglayacaktir.Calismada HACCP sisteminin yedi ilkesi uygulanmis ve bes kritik kontrol noktasi belirlenmistir.

Gida the Journal of Food, Oct 1, 1995

Uludağ arıcılık dergisi, May 19, 2023

In this research, heavy metal contents (Al, As, Pb and Cd) of 6 honey samples obtained from Marma... more In this research, heavy metal contents (Al, As, Pb and Cd) of 6 honey samples obtained from Marmara and Aegean regions of Turkiye (chaste berry, chestnut, jerusalem torn and sunflower kind of honeys) and 4 honey samples obtained from Bulgaria (lavender, acacia and sunflower kind of honeys) with micro and macro element contents including Ba, Cr, Co, Ni, Fe, Cu, Zn, Mn, Mg, P, B, Na, K, Sr, S and Ca were analyzed by ICP-OES (Inductively Coupled Optical Emission Spectrometer). It was found that the heavy metal contents (Al, As, Cd and Pb) in the investigated honey samples were below the toxic limit values specified by the World Health Organisation and the Turkish Food Codex. In general, the mineral contents of honey samples vary according to the regions where they were taken. Among the honey samples taken from different regions; the contents of Pb, Al, As, Cr, Cu, Ba, Sr, Zn, B, Ca, K, Na, P and S changed at 1% significance level, while Mn, Ni and Fe contents differ at 5% level of significance. It was determined that as the apiary locations from which honey samples were taken approached the urban areas, the Pb content increased statistically by 1%, while the As and Co content increased at the 5% level of significance.

Atatürk Üniversitesi İktisadi ve İdari Bilimler Dergisi, 2004

Journal of obesity and chronic diseases, 2020

Kombucha is a fermented beverage that is produced by fermenting tea and beet sugar solution under... more Kombucha is a fermented beverage that is produced by fermenting tea and beet sugar solution under aerobic conditions by adding symbiotic culture (yeasts and acetic acid bacteria) named as SCOBY. The health benefits of Kombucha are mainly associated with the phenolic content of substrate and the microbiota of Kombucha cultures. Olive leave and honey contain various antioxidant phytochemicals and have been used as folk medicine for long time in the form of infusion or can also be used directly. Phenolic compounds play role as antioxidant to reduce cardiovascular and neurodegenerative diseases. They also cause to weight loss, reduce the dimension of adipose tissue and blood triglyceride level, promote digestion, and lower the inflammation. The main objective of this research was to develop a beverage using dried olive leaf (0-5%) and honey (20 °Brix) as an alternative to beet sugar required for the Kombucha fermentation. Phenolic contents of extractable and hydrolysable extracts and the antioxidant activity of the fermented Kombucha beverages supplemented with beet sugar were higher following to the fermentation. The maximum phenolic contents were determined at the 12 th day. However, the bioavailability of phenols in the beverages supplemented with honey and olive leaves was much higher than the samples supplemented with beet sugar only.

Quality Assurance and Safety of Crops & Foods, Aug 17, 2015

This study was conducted to evaluate the effectiveness of a combination of specific organic acids... more This study was conducted to evaluate the effectiveness of a combination of specific organic acids for disinfecting fresh cut broccoli floret samples contaminated with Listeria monocytogenes serotype 1/2b and Salmonella enterica serovar Typhimurium. In addition, the effects of organic acids on the microbial load of broccoli samples during storage at +4 °C were determined for 7 days. The organic acids tested were acetic, benzoic, sorbic, fumaric, malic, tartaric, lactic and succinic acids and the concentrations used were 1 and 2% (w/v and v/v). L. monocytogenes and S. Typhimurium were grown on the selective media before the contamination. The broccoli samples were dipped first into the pathogen solutions containing L. monocytogenes and S. Typhimurium, then into the organic acids and subsequently counted on Oxford agar and bismuth sulphite agar, respectively. The broccoli samples dipped into the organic acids without pathogen culture were also investigated in terms of total mesophilic aerobic microorganisms, psychrotrophic microorganisms, Pseudomonas spp., total lactic acid bacteria, Enterobacteriaceae spp. and total yeast-moulds for 7 days stored at 4 °C. S. Typhimurium and L. monocytogenes log reductions were determined at between 3 to 3.28 and 2.63 to 2.84 log colony-forming units/g with 1 and 2% of malic acid and between 3.68 to 4.17 and 2.68 to 2.9 log with 1 and 2% of tartaric acid, respectively. The malic, tartaric, lactic, succinic acids and acetic acid in the tested concentrations could be used to inhibit S. Typhimurium and L. monocytogenes and prolong the shelf-life of fresh-cut broccoli.

Journal of Food Processing and Preservation, Oct 17, 2013

ABSTRACT

DergiPark (Istanbul University), Jun 1, 1996

Journal of Food Quality, Oct 1, 2003

The contents of ascorbic acid, chlorophyll andpectin in kiwifruits (Hayward cubivar) grown in Tur... more The contents of ascorbic acid, chlorophyll andpectin in kiwifruits (Hayward cubivar) grown in Turkey were investigated. While chlorophyll and pectin contents were similar to previous studies, the ascorbic acid content tended to be lower.

Journal of Food Process Engineering, Jun 1, 2008

It is essential that sterilization values be calculated through measurements of temperature from ... more It is essential that sterilization values be calculated through measurements of temperature from the coldest point of the can during thermal sterilization. However, in practice, the taking of such measurements in an operating food plant can be quite difficult because of time restrictions, and the number of thermocouples and measurements required. For this reason, it is necessary to develop a more convenient way of estimating F values that uses experimental methods through multiple regression models. The distribution of F values and the correlation between the retort temperature and the cold spot temperature of the can were taken into consideration using statistical methods. The estimated results were calculated with very low SD. It was found that there was a close relation between temperatures of retort and cold spot with a high correlation ratio, and thus it could be concluded that it is possible to use retort temperature in the estimation of F values, statistically. The experimental and estimated mean averages of F values were calculated as 13.59 and 13.59 for a 0.5-kg can, 14.15 and 14.16 for a 1-kg can, and 8.22 and 8.22 for a 5-kg can. A high correlation was found between the experimental and estimated F values (0.91 for a 0.5-kg can, 0.86 for a 1-kg can and 0.96 for a 5-kg can; P < 0.001). It was also noted that an inversely proportional relation exists between the size of the can and the F value.

Acta Agriculturae Slovenica, 2011

A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidop... more A number of health benefits have been claimed for probiotic bacteria such as Lactobacillus acidophilus, Bifidobacterium spp. and Lactobacillus casei. These benefits include antimutagenic effects, anti-carcinogenic properties, improvement in lactose metabolism, reduction in serum cholesterol and immune system stimulation. Because of the potential health benefits, these microorganisms are increasingly being incorporated into dairy foods. Several studies in recent years have shown the benefits deriving from the ingestion of probiotics and a large number of products containing lactobacilli and bifidobacteria formulated. The purpose of this study was to develop a pudding with cacao to which probiotic microorganisms were added and investigate the viability of probiotic microorganisms during the shelf-life along 25 days at 4 °C. Organoleptic properties of the puddings were also evaluated during the storage. Bifidobacterium animalis ssp. lactis LAFTI B94, Lactobacillus acidophilus LAFTI L10 and Lactobacillus casei LAFTI L26 cultures were activated and incorporated into the product. Pudding with cacao was shown to be a good vehicle for the delivery of Bifidobacterium animalis ssp. lactis, Lactobacillus acidophilus during 15 and 25 days respectively and these microorganisms did not interfere in the sensorial preferences of the product except Lactobacillus casei. The pH values and organoleptic scores of the pudding samples, except Lactobacillus casei LAFTI L26 containing ones, did not change for 20 days during the storage period, statistically (P<0.01). The pudding containing Lactobacillus casei LAFTI L26 was taken the lowest sensorial scores. The all samples were lost their organoleptic properties at the 25 days of storage period.

Food Science and Technology, Jun 1, 2021

Anthocyanins have a great potential for human health, as a subgroup of phenolic compounds. Intera... more Anthocyanins have a great potential for human health, as a subgroup of phenolic compounds. Interactions of anthocyanin involved in digestion and thus in obesity consist of inhibition of pancreatic lipase, regulation of lipolysis and lipogenesis, activation of an activated protein kinase enzyme, controlling of digestion hormones (leptin, insulin, ghrelin, cholecystokinin, GIP, GLP-1). Anthocyanins are the compounds that can control metabolic syndrome and obesity by ameliorating lipid metabolism, increasing energy expenditure, suppressing food intake and inhibiting lipid absorption. In addition, the interactions with other compounds during the processing and/or in the intestinal canal can change their absorption capability and bioavailability. Activation of mitogen-activated protein kinase and cyclooxygenase (COX) enzymes, inflammatory cytokines signaling, free-radical scavenging activity are among the primary functions of anthocyanins playing role in the basic metabolic pathways. Anthocyanins also interact with gut microbiota that plays a role in many metabolic pathways. In the review, the effects of anthocyanins on the obesity-associated mechanisms in the metabolism are considered and summarized under the light of recent researches.

Food Science and Biotechnology, Dec 1, 2011

The present investigation was to evaluate the antioxidant and antibacterial activities of hexane ... more The present investigation was to evaluate the antioxidant and antibacterial activities of hexane and methanol extracts from Origanum vulgare ssp. hirtum and Thymus vulgaris (Komotini, Greece). The methanol extracts of oregano and thyme against DPPH radical were more active than the hexane extracts (mean values 0.94 and 0.47, respectively) and oregano exhibited stronger activity than thyme (mean values 0.82 and 0.55, respectively). The results from the β-carotene/linoleic acid assay showed that all plant extracts inhibited linoleic acid oxidation up to 70.78±1.17%. The oregano extracts exhibited the strongest inhibition against Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus using the disc diffusion assay. The chemical composition of the hexane and methanol extracts, by using GC-MS, showed that carvacrol, thymol, and p-cymene were the most prominent compounds. The methanol extract of oregano was found the most potent antioxidant with the highest content of total phenolics (138.92 mg GA/g extract) and carvacrol (76.7%).

DergiPark (Istanbul University), Oct 1, 1995

DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2010

Acta Veterinaria Brno, 2012

Effects of seven different solutions prepared from various additives (carrageenan, konjac flour, ... more Effects of seven different solutions prepared from various additives (carrageenan, konjac flour, phosphate, yeast extract, xanthan gum and maltodextrin) were used to test for the first time in the marination of experimental seafood. The additives were added into the marination solutions and the samples were analyzed before and after marination. Statistically, the experimental solutions did not cause significant changes in pH, acidity and salt content of the samples (P < 0.05). The highest weight gains were obtained from the solution which contained 0.1% of konjac flour (E425 I) as 4.01, 5.21, 4.61 and 4.88 % in the mussels, big squids, diced squids and small squids, respectively. However, this solution was not preferred by the panellists because of its sticky texture. Inversely to red meat products, the solution containing phosphate caused weight loss during marination. The results indicate that the solution containing 0.2% carrageenan LM (low methoxyl) was the best solution in the marination process. Dipping into this solution caused weight gains of 4.69, 2.98, 4.04 and 2.78% in the big squids, the mussels, the small squids and the diced squids, respectively (P < 0.01). The organoleptic properties (mouth feel, flavour and softness) of mussels and squids were also improved by carrageenan LM addition.

Food Science and Technology, Mar 1, 2021

Black carrot, which is an economically important product, is produced extensively in Konya and Ha... more Black carrot, which is an economically important product, is produced extensively in Konya and Hatay regions in Turkey. Kombucha tea is a symbiotic system, comprises of bacteria and yeasts cultures called as SCOBY, and produced by fermentation of sugar and tea leaves. Kombucha samples contained black carrot juice in two concentrations (10 and 20%) and compared with the Kombucha contained green tea leaves. Black carrot varieties were used for enrichment of Kombucha production and investigated in terms of physico-chemical properties and antioxidant capacity. Black carrot samples belonging to the Hatay region, have higher anthocyanin content (660.26 mg C3G/100 g-dw), antioxidant capacity (TEAC ABTS and TEAC CUPRAC ; 15.33 ± 0.39 and 21.91 ± 0.28 µmole Trolox/g), total phenolic content (67.22 ± 0.24 mg/g GAE) and bioaccessibility (36.48 ± 0.78 mg/g GAE) comparing to Hatay black carrot variety. The highest anthocyanin content (71.05 mg C3G/100 mL), antioxidant capacity (TEAC ABTS and TEAC CUPRAC ; 3.67 ± 0.15 and 12.33 ± 0.11 µmole Trolox/g) were obtained from Kombucha tea containing black carrot juice (20%). According to the sensorial evaluation, panelists stated that the Kombucha samples with Hatay Black carrot juice had a fresh and pleasant taste and flavor due to green tea aroma.