Filiz Altay

A review on traditional Turkish fermented non-alcoholic beverages: Microbiota, fermentation process and quality characteristics

Shalgam juice, hardaliye, boza, ayran (yoghurt drink) and kefir are the most known traditional Turkish fermented non-alcoholic beverages. The first three are obtained from vegetables, fruits and cereals, and the last two ones are made of milk. Shalgam juice, hardaliye and ayran are produced by lactic acid fermentation. Their microbiota is mainly composed of lactic acid bacteria (LAB). Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus paracasei subsp. paracasei in shalgam fermentation and L. paracasei subsp. paracasei and Lactobacillus casei subsp. pseudoplantarum in hardaliye fermentation are predominant. Ayran is traditionally prepared by mixing yoghurt with water and salt. Yoghurt starter cultures are used in industrial ayran production. On the other hand, both alcohol and lactic acid fermentation occur in boza and kefir. Boza is prepared by using a mixture of maize, wheat and rice or their flours and water. Generally previously produced boza or sourdough/yoghurt are used as starter culture which is rich in Lactobacillus spp. and yeasts. Kefir is prepared by inoculation of raw milk with kefir grains which consists of different species of yeasts, LAB, acetic acid bacteria in a protein and polysaccharide matrix. The microbiota of boza and kefir is affected from raw materials, the origin and the production methods. In this review, physicochemical properties, manufacturing technologies, microbiota and shelf life and spoilage of traditional fermented beverages were summarized along with how fermentation conditions could affect rheological properties of end product which are important during processing and storage.

The uniaxial and coaxial encapsulations of sour cherry (Prunus cerasus L.) concentrate by electrospinning and their in vitro bioaccessibility

Sour cherry (Prunus cerasus L.) is rich in polyphenols which are known to be protective agents against several diseases. Polyphenols are highly sensitive against temperature, pH, oxygen, and light conditions, leading to low bioaccessibility. In this study, polyphenols of sour cherry concentrate (SCC) were encapsulated by uniaxial or coaxial electrospinning with gelatin or gelatin-lactalbumin. Results showed that phenolic acids had higher encapsulation efficiencies than anthocyanins. Encapsulation efficiencies were found as 89.7 and 91.3% in terms of phenolic acids and 70.3 and 77.8% in terms of flavonoids for the uniaxially electrospun samples with gelatin and gelatin-lactalbumin, respectively. The content of polyphenols in SCC decreased after intestinal tract whereas all electrospun samples showed improved bioaccessibility. According to in vitro digestion results, electrospinning encapsulation provided 8 times better protection of cyanidin-3-glucoside compared to the non-encapsulated SCC. Results showed that especially coaxial electrospinning encapsulation is an effective method for sour cherry polyphenols.

Rheology and Functionality of Ayran—A Yogurt Drink

Milk is considered a miracle natural food in which fat exists as an emulsion. Yogurt is known for its health benefits, being a fermented milk product. It has a viscoelastic gel structure. Both are regarded as healthy foods and there have been many reports about their health functionality. These healthy foods have also received attention from consumers, researchers, and manufacturers. The concept of new product design starts from the consumer needs and demands, based on daily life requirements. This concept includes not only designing a new product but also making the product functional. These two characteristics of designing a new product can only be realized by understanding the structure–function relations of components in foods. It appears that this point is missing in the literature. Ayran, a yogurt drink, is a traditional fermented drink in Turkey and neighboring countries, with various reported benefits. Its rheological properties have continued to be studied to understand its stability and textural problems during manufacture, transportation, storage, and consumption. As functional foods have become a trend, its functional properties have also been studied with additions of “functional” ingredients such as probiotics or prebiotics. In this review, functional and rheological studies of ayran are discussed.