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Öğe Angiotensin-converting enzyme inhibitory and starter culture activities in probiotic yoghurt: Effect of sodium-calcium caseinate and whey protein concentrate(Wiley, 2018) Akalin, Ayse Sibel; Unal, Gulfem; Dinkci, NayilThis study investigated the effect of fortification with sodium-calcium caseinate (SCaCN), whey protein concentrate (WPC) or a blend of those ingredients on some properties of probiotic yoghurt. At the beginning of the storage, the highest angiotensin-converting enzyme inhibitory activity (ACEI %) was obtained from yoghurts with SCaCN. However, the levels of proteolytic and ACEI activities were highest in WPC-supplemented yoghurt after 14 and 28days. The highest Bifidobacterium animalis subsp. lactis Bb12 viability was obtained in yoghurts with WPC or the SCaCN-WPC blend. A gradual increase in lactic acid was also obtained in the yoghurts supplemented with WPC or with the SCaCN-WPC blend; there was no increase in acetic acid.Öğe Antioxidant activity of commercial dairy products(Teknoscienze Publ, 2012) Unal, GulfemAntioxidant activity of foods is important both for shelf life of the product and also protection from oxidative damage in the human body. Select brands of milk, yoghurt, fresh cream cheese and kefir were screened for antioxidant activity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and iron chelating activity methods. Fermented dairy products containing types of berries (strawberry, blueberry, blackberry, raspberry) showed higher (p<0.05) antioxidant activity when compared to plain products or containing other fruits. For both methods, the highest antioxidant (p<0.05) activity was observed in fresh cream cheese group.Öğe Antioxidant activity of milk proteins(Teknoscienze Publ, 2006) Unal, Gulfem; Akalin, A. SibelFree radicals and active oxygen species are toxic as they can oxidize biomolecules leading to cell death and tissue injury. From another point of view; lipid oxidation is also a major cause of chemical spoilage in foods. It leads to many undesirable changes in flavour, texture and nutritional value in foods. Therefore, food processors must control lipid oxidation in their products as much as possible. Milk proteins, caseins and whey proteins, have important roles in preventing lipid oxidation and maintaining milk quality. Creating a market for the use of milk proteins as antioxidants would not only decrease spoilage of foods by lipid oxidation and improve human health but would also increase milk protein utilization and decrease whey disposal costs.Öğe Antioxidant and angiotensin-converting enzyme inhibitory activity of yoghurt fortified with sodium calcium caseinate or whey protein concentrate(Springer France, 2012) Unal, Gulfem; Akalin, A. SibelIn this study, the effect of fortification of yoghurt with sodium calcium caseinate (SCC) and whey protein concentrate (WPC) on the antioxidant and angiotensin-converting enzyme (ACE) inhibitory activity was assessed. Milk was fortified with skim milk powder (SMP) as control, SCC, and WPC at 2% and 4% ratios. The antioxidant activity was determined using 2,2,-diphenyl-1-picrylhydrazyl (DPPHaEuro cent) radical scavenging, hydrogen peroxide (H2O2) scavenging, and Fe2+ chelating activity methods. Yoghurt fortified with 4% WPC had the highest DPPHaEuro cent scavenging activity, whereas there were no significant differences between yoghurt samples containing SMP and SCC at both fortification levels. In the Fe2+ chelating activity method, increase in incubation time (from 0 to 60 min, at room temperature) significantly improved the chelating effect of all yoghurt types. Yoghurts supplemented with WPC and 4% SMP showed higher Fe2+ chelating activity than those fortified with SCC for all incubation times. Experimental yoghurts also possessed antioxidant activity towards H2O2 except yoghurts fortified with WPC at a concentration of 0.2 ga (TM) mL(-1). Yoghurt containing 4% WPC showed higher H2O2-scavenging activity than those supplemented with 4% SCC at 0.05 and 0.1 ga (TM) mL(-1) concentrations, at 0 and 40 min. Addition of SCC or WPC caused an increase in the ACE inhibitory activity of yoghurt when compared to supplementation with SMP. Fortification of yoghurt with WPC was more effective than that of with SCC in terms of ACE inhibitory activity.Öğe Determination of some chemical and microbiological characteristics of Kaymak(Inst Grasa Sus Derivados, 2006) Akalin, Ayse Sibel; Gonc, Siddik; Unal, Gulfem; Okten, SevtapKaymak is a kind of concentrated cream, which is traditionally manufactured from buffalo or cow's milk in Turkey. It is generally consumed with honey at breakfast and some traditional Turkish desserts. The aim of this study was to determine some chemical and microbiological properties of kaymak. The samples were obtained from different dairy plants producing kaymak from cow's milk and local markets located in Izmir. They were examined for total solids and fat contents, acidity, pH and peroxide values, as well as counts of coliform bacteria, E. coli, yeast and moulds, and Staphylococci. Chemical characteristics of the samples were generally favorable for Turkish Food Codex. However, microbiological properties of some samples were very poor. Careful considerations should be given by the kaymak industry during manufacturing and storage of the product.Öğe Effect of Supplementation with Green and Black Tea on Microbiological Characteristics, Antimicrobial and Antioxidant Activities of Drinking Yoghurt(Ankara Univ, Fac Agr, 2018) Unal, Gulfem; Karagozlu, Cem; Kinik, Ozer; Akan, Ecem; Akalin, Ayse SibelThe influence of supplementation with green and black tea on microbiological properties, antimicrobial and antioxidant activities of drinking yoghurt were investigated during 21 days of storage. The samples supplemented with 2% either green or black tea had higher viable counts of both yoghurt starter bacteria than those of infused by the ratio of 4%. Both green and black tea extracts showed antimicrobial activity on E. coil, B. cereus, S. aureus and C. albicans however this effect was detected higher in samples containing green tea. The samples added green tea extract had the highest DPPH scavenging activity when compared to those supplemented with black tea extract throughout the storage. Green tea had a superior effect than black tea in terms of total phenolic content of drinking yoghurt samples.Öğe The effects of black and green tea on antioxidant activity and sensory characteristics of kefir(Teknoscienze Publ, 2017) Karagozlu, Cem; Unal, Gulfem; Akalin, A. Sibel; Akan, Ecem; Kinik, OzerThe effects of supplementation with green and black tea on chemical and sensory properties and antioxidant activities of kefir were investigated during 21 days of storage. pH and titrable acidity values were within acceptable levels during 21 days of storage. Total dry matter, fat and lactic acid contents of all samples were in accordance with Turkish Food Codex. The samples containing green tea extract had the highest DPPH center dot scavenging activity compared to those of supplemented with black tea extract throughout the storage. Green tea had a superior effect compared to black tea in terms of total phenolic content of kefir samples. Statistical differences change between parameters kefir samples. CK (control) group received higher scores compared to those in black and green tea groups and they were also appreciated by the panelists during storage. All kefir samples with added black or green tea showed acceptable sensory scores.Öğe Evaluation of the Functional and Sensory Properties of Probiotic Whey Cheese with Herbs in Vacuum or Modified Atmosphere Packaging(Faculty Food Technology Biotechnology, 2024) Unal, Gulfem; Akyil, Didem Ekin; Akalin, Ayse SibelResearch background. Some herbs provide functional properties to foods, especially their antibacterial and antioxidant properties. On the other hand, modified atmosphere packaging is being considered as an alternative to vacuum packaging to preserve the functional and sensory properties of foods. Since the shelf life of whey cheese is quite short, different packaging methods such as modified atmosphere packaging are favoured. Besides, the addition of herbs both gives flavour to the cheese and improves its functional properties. Experimental approach. In the present study, oregano ( Origanum onites) ) or rosemary ( Rosmarinus officinalis) ) was added to probiotic whey cheese (lor) containing Lactobacillus acidophilus La-5 and Bifidobacterium lactis Bb-12 under modified atmosphere packaging (MAP) (80 % CO2 2 and 20 % N2) 2 ) or vacuum packaging. The physicochemical, microbiological and sensory properties as well as antioxidant and proteolytic activities of the cheese samples were determined. Results and conclusions. The addition of herbs did not negatively affect the viable counts of B. lactis and L. acidophilus, , and the cheese samples contained at least 8 log CFU/g of both probiotic bacteria for 35 days. MAP improved the viability of B. lactis and L. acidophilus in cheese with rosemary during the first few weeks of storage compared to vacuum packaging. The addition of herbs significantly increased the total phenolic content and antioxidant activity under both MAP and vacuum. MAP improved the antioxidant activity of lor cheese with added herbs on days 14 and 28 more than vacuum packaging. Lor cheese with rosemary under MAP conditions showed the highest DPPH center dot (2,2,-diphenyl-1-picrylhydrazyl) scavenging activity and also the highest proteolytic activity throughout storage. The sample with rosemary under MAP had the highest taste and aroma scores throughout the entire storage period. Fortification with herb and MAP offers advantages in the production of whey cheese. The use of rosemary and modified atmosphere packaging makes it possible to achieve high viability of probiotic bacteria, total phenolic content, antioxidant activity and sensory acceptance in lor cheese. Novelty and scientific contribution. This is the first study in which both different herbs and different packaging methods were applied to probiotic whey cheese (lor). The study shows that the functional properties of whey cheese can be improved by using different herbs under different packaging conditions. Among the analysed properties of the product, the improvement of the viability of probiotic bacteria is particularly valuable for human health. Thus, it contributes to the science of functional food and enables the use of these parameters in some other foods.Öğe Importance of probiotics in oral health(Teknoscienze Publ, 2011) Unal, GulfemProbiotics are living microorganisms that are safe for human consumption and have beneficial effects on human health. The main field of researches on probiotics has been in the gastrointestinal tract. However, in recent years oral health has also been in the scope of research. In this review, the mechanisms of probiotic actions in oral cavity and researches that deal with oral health are evaluated. Consumption of probiotic dairy products and administration of medical device containing probiotics are assessed in perspective of oral therapy. Health benefits of probiotics have been demonstrated both in vitro and in vivo studies. It is concluded from this review that much more investigations should be held to make the effects of probiotics clear; so that probiotic therapy can be recommended for oral health purposes.Öğe Influence of fortification with inulin and Hi-maize on textural and sensory properties of set-type probiotic yoghurt(Croatian Dairy Union, 2018) Unal, Gulfem; Ozer, ElifThe aim of this research was to investigate the effect of fortification with inulin and resistant starch (Hi-maize) on textural and sensory properties of set-type probiotic yoghurt containing Lactobacillus acidophilus during 21 days of storage. Textural characteristics were evaluated by determining firmness, adhesiveness and apparent viscosity parameters. Milk was fortified with inulin or Hi-maize at 2 % or 4 % ratios, whereas the control group had no supplement. Probiotic yoghurt supplemented with 2 % Hi-maize was firmer than that supplemented with 2 % inulin, except at the beginning of storage. There were no significant differences among the firmness values of yoghurt samples fortified by inulin and Hi-maize when the ratio increased to 4 %. The addition ratio of inulin or Hi-maize did not significantly affect adhesiveness. Supplementation with 2 % inulin or Hi-maize did not alter viscosity of yoghurts at most of the storage days. Sensory attributes were evaluated as taste, appearance, aroma, texture and overall acceptability. In general, there were no significant differences in sensorial parameters between yoghurts added with inulin or Hi-maize. Neither the addition rate nor the storage period affected the sensory scores of the samples. Significant reductions (P<0.05) of taste, appearance, aroma and overall acceptability scores of the control probiotic yoghurt were determined at the end of storage when compared to the 1st day.Öğe Influence of fortification with sodium-calcium caseinate and whey protein concentrate on microbiological, textural and sensory properties of set-type yoghurt(Wiley-Blackwell, 2013) Unal, Gulfem; Akalin, A. SibelThe effect of fortification of yoghurt with sodiumcalcium caseinate (SCC) and whey protein concentrate (WPC) on some properties of set-type yoghurt were investigated. The addition of WPC enhanced the viability of Lactobacillus delbrueckii subsp. bulgaricus more than SCC. The highest firmness values were obtained from SCC-fortified yoghurts, whereas yoghurts fortified with WPC had the highest water-holding capacity during storage. The yoghurts fortified with 4% w/w SCC or 4% w/w WPC had the highest viscosity. Yoghurts fortified with 2% w/w SMP, SCC or WPC showed similar taste and overall acceptability scores; however, samples containing 4% w/w SCC or 4% w/w WPC had the lowest scores.Öğe Milk proteins and hypertension(Teknoscienze Publ, 2006) Unal, Gulfem; Akalin, A. SibelHypertension has an important role in cardiovascular diseases, including coronary heart disease, peripheral arterial disease and stroke. Angiotensin converting enzyme (ACE) is effective in the regulation of blood pressure because it catalyzes the formation of the potent vasopressor angiotensin II from angiotensin I. Therefore, inhibition of this enzyme can generate an antihypertensive effect. Milk proteins are precursors of antihypertensive peptides which were also identified from fermented milks and cheeses. However it is necessary to study the mechanism of the antihypertensive effect in vivo. This paper has focussed on production of ACE inhibitory peptides and antihypertensive effects of milk protein hydrolysates and dairy products. Clinical trials in hypertensive animals and humans indicate that these hydrolysates and peptides derived from milk protein can cause a significant reduction in hypertension. So they can be named as functional food ingredients due to their reducing effects of risk of hypertension. Finally, there is the possibility of pharmaceutical and commercial use of the antihypertensive peptides because of their mild effect and safety within the human body.Öğe Quince Powder Increases Antioxidant Activity and Probiotic Survival in Yoghurt(Faculty Food Technology and Biotechnology, 2024) Cinar, Senay Burak; Unal, Gulfem; Koc, Gulsah Caliskan; Dirim, Safiye Nur; Akalin, Ayse SibelResearch background. In recent years, there has been a growing interest in incorporating fruit-based additives into yogurt formulations as a means to improve the functionality of the product. This study aims to produce a functional product by incorporating quince, which is rich in fibre, vitamins, minerals and antioxidant activity, into a yoghurt formulation. Experimental approach. The influence of the addition of quince powder (0 (control), 0.5, 1.0 and 1.5 %) on the antioxidant and proteolytic activities and culture viability of probiotic yoghurt was investigated for 28 days. Results and conclusions. The viable counts of yoghurt bacteria and Bifidobacterium lactis BB-12 (R) were above 8 log CFU/g. Higher viability of all bacteria was obtained in yoghurt fortified with 1.5 % quince powder than those of other samples after 14 days. Probiotic yoghurt with added 1.5 % quince powder had the highest proteolytic activity during the last two weeks of storage, while the highest total phenolic content and (2,2-diphenyl-1-picrylhydrazyl) radical (DPPH center dot) scavenging activity were obtained for the same sample throughout the storage period. Noveltyand scientificcontribution. Quince powder supports the health of the digestive system thanks to its high fibre content, while it is also rich in vitamins, minerals and antioxidant activity. These properties emphasise the importance of using quince powder in yoghurt production. This innovation has the potential to provide consumers with a tasty alternative, while at the same time increasing the intake of health-promoting ingredients. Furthermore, such products offer higher nutritional value than conventional yoghurt, offering consumers with a healthier option. Therefore, the production of yoghurt with quince powder can be considered as an important innovation in the field of nutrition and a practice that contributes to increasing health awareness.Öğe Textural and sensorial characteristics of set-type yogurt containingBifidobacterium animalissubsp.lactisBb-12 and quince powder(Springer, 2020) Cinar, Senay Burak; Koc, Gulsah Caliskan; Dirim, Safiye Nur; Unal, Gulfem; Akalin, Ayse SibelThe aim of this study was to investigate the effect of quince powder (QP) on the textural and sensory properties of set-type yogurt, containingBifidobacterium animalsssp.lactisBb12, as a function of concentration, during 28 days of refrigerated storage. For this purpose, the fresh quinces were peeled, the seeds removed, the quince cut into slices, then convectively dried, and then ground into a powder. the obtained QP was then analyzed and used in set-type yogurt formulation at different ratios (0, 0.5, 1.0, and 1.5%). the obtained QP with a particle size of d(0.5) = 78.46 +/- 6.21 mu m, a moisture content of 3.07 +/- 0.48%, water activity of 0.305 +/- 0.003, and a water-holding capacity of 3.05 +/- 0.18 g g(-1), possessed the acceptability regarding its flowability and cohesiveness values. the incorporation of QP to the milk base weakened the gel strength, while the apparent viscosity increased in yogurts fortified with 0.5% and 1.0% QP. the amount of whey loss also decreased when QP was added over the ratio of 0.5%. the color parameters of the experimental yogurts changed with the addition of QP, providing an increase in the L* values and a decrease in the a* and b* values. Similar values of texture, appearance, taste, and aroma were obtained between the control and experimental yogurts fortified with 0.5% or 1% QP.
