In this study, cholesterol assimilation ratios and some probiotic characteristics of yeasts were investigated. For this purpose, yeasts were isolated from milk and foods that were naturally fermented and not containing starter culture. In vitro cholesterol assimilation properties were determined in media. The Cholesterol assimilation by yeast strains ranged between 1.36 and 73.33%. Twenty-one yeast strains showing high assimilation percentage were selected, and their acid tolerance, bile tolerance, bile salt deconjugation activity and survival in simulated gastrointestinal conditions were investigated. Among the strains assessed, 12 of them showed probiotic characteristics.

Propolis is attracting great interest due to functional effects such as antibacterial, antioxidant and anticancer. Therefore, studies about the use of propolis in food products and increasing propolis consumption in human nutrition have increased in recent years. Propolis contains phenolic compounds, essential oils, aromatic acids and waxes which are responsible for biological effects. Many factors such as plant resources, geographical regions and environmental conditions affect the chemical composition of propolis. Propolis enrichment in food products to improve the nutritional value, quality and functionality of food have been investigated in many studies. Furthermore, it was reported that propolis can meet the demand of consumers about the use of natural food additive in food manufacturing. The aim of the present study was to introduce the physicochemical composition and biological activity of propolis and review the studies about its applications in food products.

Foodborne illness and deaths caused by pathogenic microorganisms have become important public health concerns in recent years.Dangerous pathogens can easily contaminate foods and cause foodborne diseases. Ready-to-eat products like salad and ice cream are especially vulnerable and can cause foodborne diseases because these foods are not exposed to any further treatments before consumption to eliminate dangerous microorganisms. The nutritional value of ice cream is high due to its milk content. Therefore, it is a good nutritious source for the development of pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, Salmonella, Listeria monocytogenes, Shigella, Campylobacter jejuni, and Bacillus cereus (Gundogan & Avci, 2014).Many foodborne diseases due to the contamination of L. monocytogenes in dairy products such as ice cream were reported all over the world (Callejón et al., 2015;Dean & Zottola, 1996;Silk et al., 2013). Furthermore, Crawford (2007) and Scallan et al. (2011) reported that every year, approximately 2,500 cases of listeriosis caused by L. monocytogenes occurs and it is one of the most important causes of death due to foodborne diseases in the United States.

Bu çalışma kapsamında nar (Punica granatum L.) çiçeğinden farklı parametreler altında elde edilen ekstraktların antioksidan aktiviteleri ve toplam fenolik içerikleri üzerine ekstraksiyon koşullarının etkisi incelenmiştir. Nar çiçeklerinden su ve etanol kullanılarak 40-60 °C sıcaklık ve 40-60 dk süre ile ekstraktlar elde edilmiş ve liyofilize edilerek kurutulmuştur. Liyofilize ekstraktların antioksidan aktiviteleri 2,2-difenil-1-pikrilhidrazil (DPPH) radikal giderme aktivitesi ve β-karoten ağartma yöntemleri kullanılarak tespit edilmiştir. Çalışma sonuçları, ekstraktların antioksidan aktivite ve fenolik madde içeriğine ekstraksiyon sırasında kullanılan çözücü, sıcaklık, süre ve bu faktörlerin bazı interaksiyonlarının önemli seviyede etkisi olduğunu göstermiştir. Etanol ile hazırlanan ekstraktların su ile hazırlanan ekstraktlara kıyasla daha yüksek antioksidan aktivite gösterdiği belirlenmiştir. Ayrıca etanol ile hazırlanan ekstraktların toplam fenolik madde içeriği de daha yüksek bulunmuştur. Etanol kullanılarak, 60 °C sıcaklık ve 40 dk sürede gerçekleştirilen ekstraksiyon işlemi ile elde edilen ekstraktların ortalama %85 DPPH radikali giderim aktivitesine ve %70 β-karoten ağartma aktivitesine sahip olduğu belirlenmiştir. Bu ekstraktların ortalama 70.36 mg GAE-g fenolik bileşen içerdiği tespit edilmiştir.

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